10e - PTFE-lined centric butterfly valve
The Pfeiffer BR10e PTFE-lined centric control butterfly valve is designed for general service applications up to the limits of the PN16 pressure class rating. These general service applications focus on extremely corrosive media found in chemical processes. The Pfeiffer BR10e design increases flow capacity but also reduces the pressure recovery factor, making the design more susceptible to cavitation, flashing, and flow noise generation. The centric design of this butterfly valve will require greater breakaway torques from the actuator.
The Pfeiffer BR10e can be assembled with a pneumatic, electric or hydraulic actuator also offered by the SAMSON Group to complete the construction of the control valve. These control valves are designed according to the modular assembly principle and can be equipped with SAMSON Group actuators and valve accessories such as positioners, limit switches, and solenoid valves.


Northwest River Water Treatment Plant Construction / Chesapeake, VA
How do you renovate a water treatment facility?
The Northwest River Water Treatment Plant improves the quality of water for the City of Chesapeake, Virginia through the use of Reverse Osmosis Membrane Treatment. This project included the construction of the new chemical and membrane treatment facilities and renovations to the existing filtration treatment facilities. Utilizing four each 2 MGD Surface Water Membrane Trains and two each 2 MGD Groundwater Membrane Trains, the plant improvement removes objectionable sale from the Chesapeake's sole water supply.
Facts And Figures
Projects Delivery Method Child Item


The QXM series pumps are designed to provide efficient and reliable hydraulic power transmission.
They are known for their compact size, high performance, and robust construction. These pumps are suitable for use in a wide range of industries, including manufacturing, construction, agriculture, and material handling.
Let's start with the QXM51 model. It is a hydraulic gear pump with a maximum displacement of 4.92 cubic centimeters per revolution (cc/rev). The QXM51 pump operates at a maximum pressure of 250 bar and delivers a maximum speed of 4000 revolutions per minute (RPM). With its compact design and lightweight construction, this pump offers excellent versatility and ease of installation.
Moving on to the QXM52 model, it offers a slightly higher displacement of 9.84 cc/rev. This increased displacement allows for higher flow rates, making the QXM52 pump suitable for applications that require more hydraulic power. The maximum pressure and speed ratings for the QXM52 pump are the same as the QXM51 model, at 250 bar and 4000 RPM, respectively.
Finally, let's discuss the QXM53 model. This pump offers the largest displacement among the QXM series, with a capacity of 19.68 cc/rev. With its higher displacement, the QXM53 pump can deliver even greater flow rates and hydraulic power. The maximum pressure rating for the QXM53 pump is 250 bar, while the maximum speed remains at 4000 RPM.
All models in the QXM series feature high-quality construction materials, including cast iron bodies and hardened steel gears.
These materials ensure durability and resistance to wear, allowing the pumps to withstand demanding operating conditions. The pumps also incorporate advanced sealing technology, which minimizes internal leakage and ensures optimal efficiency.
In terms of mounting options, the QXM series pumps offer flexibility. They can be mounted in various orientations, including horizontal and vertical positions, to suit different installation requirements. Additionally, the pumps are designed for easy maintenance, with accessible components and convenient servicing procedures.
The QXM series pumps from REXROTH are known for their reliable performance, compact design, and durability. Whether used in mobile or industrial applications, these hydraulic gear pumps deliver efficient power transmission and contribute to the smooth operation of hydraulic systems. With their wide range of displacement options and versatile mounting capabilities, the QXM series pumps provide solutions for diverse hydraulic power requirements.


TianyuMfg High-pressure flow irons for a wide variety of well service applications In stock and ready to ship!
Your factory partner for high pressure flow irons
TianyuMfg manufactures and supplies high pressure flow irons in various types of end connections, Our high pressure flow control products are capable to be operated in wide temperature range and meet your specific working pressure requests. 100% interchangeable with original Weir SPM made flow irons.
High pressure flow iron fittings with the most used end connection types in various sizes and pressure ratings:
2″ 1502 hammer union
3″ 1502 hammer union
4″ 1002 hammer union
4″ 1502 hammer union
Each integral union connection is clearly stamped with an identification code (e.g. “1502”), and this code should be referenced when mating unions.
Operating temperature range classification:
Standard temp: 0ºC/32℉~ 110ºC/230℉
Low temp: -30ºC/-22℉~ 110ºC/230℉
TianyuMfg flow control service types:
H2S (Sour Gas) Service
TianyuMfg full range flow control products
TianyuMfg manufactures and supplies flow control products including:


2011/05, CPR/Napinka Sub. mile 21.1 on bridge E. of Clearwater, MB. View – looking S.W. down on Long River and provincial road No. 342. Notice water spilling over government dam due to significant rain. Water above the dam was the water source for early steam engines. Water would be pumped from here to the pump house and up the west escarpment into the water tower as previously pictured. (Click on photo for detail) © Text and Photos exclusive copyright of N. Froese.
352 The Napinka Subdivision, Mile 0 to Mile 49.
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The Features of Cement Mixer And Pump
Posted On: 19/10/2021 | Posted by: Haomei Concrete PumpsHaomei cement mixer and pump integrates mixing and high-pressure pumping. Electric motor or diesel generator set can be used as the power system. The construction operation system is fully automated. It can be easily moved on the construction site.
The concrete mixer and pump can be used for mixing and pumping dry and wet materials such as cement, mortar, fine stone concrete, etc. Having two functions in one, it has high cost performance. can be used for mixing and pumping dry and wet materials such as cement, mortar, fine stone concrete, etc.
The concrete mixing pump can not only improve the working efficiency, but also more convenient for construction in narrow areas, sloping roofs, and high-rise buildings.
It is of PLC programmable computer control and equipped with a wireless remote control.
Double-cylinder full hydraulic pumping is adopted, which improves work efficiency and reduces failure rate.
S-pipe distribution valve
The concrete mixer machine and pump is equipped with a floating wear ring, which automatically compensates for wear and has good sealing performance. It has two working modes: low pressure with large displacement, and high pressure with small displacement.
The concrete mixer pump adopts electric and hydraulic control reversing, with sensitive response and good stability.
High outlet pressure
Its horizontal transportation can reach 400 meters to 500 meters, and vertical transportation reach 150 meters to 180 meters, which can meet the transportation requirements of high-rise buildings and long-distance construction.
The hydraulic oil cooling adopts an oil-air cooler heat dissipation system, which can greatly reduce the heat generated by the hydraulic system, and ensure that the working oil temperature of the hydraulic system is controlled below 60°C, eliminating water cooling and heat dissipation.
The sealing is reliable and it is not easy to leak; the mixing blade has a reasonable structure and can be applied to a variety of concrete ratios.
Original source: https://www.concrete-pump-cn.com/a/cement-mixer-pump.html
Tags: concrete mixer pump,


2018 9 30 brief introduction to xbs and dxbs series fine stone concrete pumps 1. xbs and dxbs fine stone concrete pumps are a kind of mortar conveying equipment specially developed according to the characteristics of floor heating projects.
xbs dxbs series products are a kind of mortar conveying equipments, specially designed for the floor heating projects according to its characteristics .. they are extensively applied in the large area and highly effective construction of fine stone concrete or mortar stuffing in floor heating projects .. environmental friendly diesel
2013 8 26 large concrete pump small concrete pump fine stone concrete pump mortar delivery pump high speed railway girder concrete pump mobile concrete placing boom stationary concrete placing boom product name xbs series small concrete pumps product type product description details. picture. scope. xbs series small concrete pump for
2019 3 21 hbt/dhbt series concrete pump plant mounted concrete boom pump plant mounted concrete pump elevator shaft self climbing concrete placing boom mobile hydraulic concrete placing boom floor climbing hydraulic concrete placing boom concrete transit mixers xbs/dxbs fine stone concrete pump manual concrete placing boom skid steer loaders
2017 6 14 xbs/dxbs fine stone concrete pump concrete mixer pump plant mounted concrete pump [email protected] introduction. small and medium concrete pump, using advanced technology of concrete pump in the world, it is the first advanced floor heating construction equipment in domestic and suitable for construction of large area, high efficiency in pea
self climbing concrete placing stationary hydraulic concrete mobile hydraulic concrete plac ship mounted hydraulic concret manual type concrete placing b fine stone concrete pump xbs series of products is the mortar transportatio
plant mounted concrete mixer pump, trailer concrete mixer pump, diesel trailer concrete pump, concrete pumps, spraying machines , concrete auto self loading 22kw small fine stone concrete conveying pump/cement grouting pump.
2017 6 7 js series concrete mixer is a kind of double shafts forced type mixer, it can be used separately and can be used together with a concrete batching machine to be a simple type concrete batching plant .. hbt/dhbt series concrete pump small and medium concrete pump xbs/dxbs fine stone concrete pump plant mounted concrete pump plant mounted
2018 11 21 concrete pumps can be divided into boom concrete pump,trailer concrete pump .. jh50 series concrete pump plant are popular small model researched and developed by our company after our hbt series trailer mounted concrete pumps, hbc series plant mounted concrete pumps and hgy series hydraulic concrete placing booms .. xbs and dxbs fine
alibaba offers 1,285 small mortar pump products. about 54 of these are concrete pumps, 15 are mortar spray machines, and 10 are pumps .. small stone concrete placing pumps fine stone mortar concrete pump manufacturer . us $13400.0 13700.0 / set . 1 set (min. order) trailer mounted small concrete pump electric 30 kw powerful cement


Victsing 80 GPH Submersible Pump Hydroponics Aquaponics Statuary Aquarium Fish W
Suction cup mounting feet for either vertical or horizontal mounting.Contains no seals or messy oils.
This submersible water pump is great for aquarium, fountains, spout and hydroponic systems.
The small profile size makes the pump easy to hide or disguise. Has adjustable flow and is easy to clean.
This submersible pump is designed for reliability and ultra-quiet operation to provide years of service.
Adjustable water flow rate.


Know about Project Swajal:
- The Ministry of Drinking Water & Sanitation has launched second project of Swajal Yojana at village Bhikampura, Karauli, Rajasthan.
- Under this project, four reservoirs will be constructed in village and common tap connection will be given to almost 300 households.
- Swajal is a community owned drinking water programme for sustained drinking water supply.
- Under the scheme, 90% of the project cost will be taken care by the Government and the remaining 10% of the project cost will be contributed by the community.
- The Operations and management of the project will be taken care by the local villagers.
- Besides ensuring the availability of clean drinking water to every household round the year, the project would also generate employment


What are the common mistakes in installing Horizontal Multistage Pump
1. There are many elbows on the water inlet pipe of Horizontal Multistage Pump
If there are many elbows used on the water inlet pipe, some water flow resistance will be added. Moreover, the elbow should be turned in a straight direction, and it is not allowed to turn in a horizontal direction to avoid gathering air.
2. When installing the water inlet pipeline, the horizontal section should be horizontal or upward
Doing so will gather air in the water inlet pipe, reduce the vacuum degree of the water pipe and the water pump, reduce the water suction head of the water pump, and reduce the water output. The correct way is: its horizontal section should be slightly skewed towards the water source, it should not be horizontal, let alone tilt upward.
3. The water inlet of Horizontal Multistage Pump is directly connected with the elbow
This will cause the water to spread unevenly as it enters the impeller through the elbow. When the diameter of the water inlet pipe is larger than the water inlet of the water pump, an eccentric reducer should be installed. The plane part of the eccentric reducer should be installed on the top, and the inclined plane should be installed on the bottom. Otherwise, the air will be collected, the water output will be reduced or the water will not be pumped, and there will be knocking noises. If the diameter of the water inlet pipe is the same as that of the water inlet of the water pump, a straight pipe should be added between the water inlet of the water pump and the elbow, and the length of the straight pipe should not be less than 2 to 3 times the diameter of the water pipe.
4. The outlet pipe of Horizontal Multistage Pump is above the normal water level of the outlet pool
If the water outlet is above the normal water level of the outlet pool, although the head of the pump is increased, the flow rate is reduced. If the water outlet must be higher than the water level of the water outlet due to the limited terrain conditions, an elbow and a short pipe should be installed at the mouth of the pipe to make the water pipe into a siphon type and reduce the height of the water outlet.
5. The position of the water inlet of the water inlet pipe is wrong
① The distance between the water inlet of the water inlet pipe and the bottom of the water inlet pool and the wall is smaller than the diameter of the water inlet. If there is dirt such as mud and sand on the bottom of the pool, if the distance between the water inlet and the bottom of the pool is less than 1.5 times the diameter, it will cause poor water intake or suction of mud and sand debris during pumping, which will block the water inlet.
②When the water inlet of the water inlet pipe is not deep enough, it will cause vortices on the water surface around the water inlet pipe, which will affect the water inlet and reduce the water output. The correct installation method is: the water depth of small and medium-sized water pumps shall not be less than 300-600mm, and the depth of large-scale water pumps shall not be less than 600-1000mm.
6. When setting the bottom valve, the bottom section of the water inlet pipe is not straight
If installed in this way, the valve cannot be closed by itself, resulting in water leakage. The correct installation method is: the bottom section of the water inlet pipe equipped with a bottom valve is preferably straight. If it cannot be installed vertically due to terrain conditions, the angle between the axis of the water pipe and the horizontal plane should be more than 60°.
The above is the detailed description of the six misunderstandings of Horizontal Multistage Pump. Horizontal Multistage Pump is a centrifugal pump with compact structure, small size, light weight, low noise, remarkable energy saving effect and convenient maintenance. It adopts standard vertical motor and quick-install mechanical seal, which is very convenient to replace.


Four Ram Fork type Single Rudder Electro-Hydraulic Steering Gear
Hydraulic Steering Gear consists of Steering mechanism, power system and control system.
Marin type of Steering mechanism:
1. Four-ram cross head hydraulic steering gear
2. Fork type（two-ram/four-ram) hydraulic steering gear）
3. Swing/tilt cylinder type
4.Rotary Vane Steering Gear
Options of pilot type for control system:
1. Follow-up pilot
2. Auto pilot
3. Emergency manual pilot
4. Engine drive pilot
Steering time and power: comply to SOLAS rules, or better as per customer’s requirements
In this case here, the steering gear system consists of four ram fork type steering mechanism, two motor pump sets, reserve oil tank, control panel and start&alarm boxes.
Single Rudder Hydraulic Shifting Yoke Steering Gear
|Type||Nominal Torque||Max. Steering Angle||Steering Time||Required Ele'c Power|
More single rudder hydraulic shifting yoke steering gear can be offered,pls contact us for more details.


RO booster pump 200 GPD is a pressure-adding device for a RO water system or water purifier. Working flow ≧1900ml/min, work current ≧1.9 A, 70 PSI pressure feeding, low noise.
Are you in search of a pressure booster pump supplier? LEFOO is always dedicated to manufacturing pressure booster pumps for RO systems and water purifiers. The LEFOO RO Booster Pump increases the water flow and adds the inlet pressure, maximizing the water production of their water purifier. prolonging the life of the components and reducing operating costs.
The pump also can be used in Drinking water chillers; Drinking water coolers; Carbonated Drink Machine; Beverage machine; Reverse osmosis system; medical water purifier; Laboratory water purifier
|LEFOO 24VDC 200GPD RO Booster Pump|
|The pumps are capable for water purifiers with a clean water production of 200 gallons per day|
3/8" Male Quick Connector3/8"Side Female Quick Connector
|Certifications||NSF, CE, ROHS, REACH, EU Food Grade|
*High water preventing level.
*Compliant with CE, Rohs, CQC certifications.
*Large flux water outlets with stable pressure and long working life.
*Compact structure consists of robust plastic and metal components.
*DC Powered strong impetus motor with low noise, low vibration level.
*Whole process quality controls in processes of electrical, sealing, and pressure boosting.
Water Vending, Dispensing
HVAC Coil Cleaning
Medical Lab Water
Endoscope Reprocessing/Chemical Boost
Dialysis Chemical Injection
Methanol & Water Injection
Sparkling Water Machine
Commercial Sparkling Water Machine
Commercial Carbonated Water Machine
Commercial Water Dispenser
RO Water Dispenser
Teeth Cleaning Industry
24 Sep 2023Harnessing Innovation: The Future of Water Treatment with Water Purifier Pumps
16 Sep 2023Unveiling Water Clarity: Exploring the Technology behind Water Purifier Pumps
08 Sep 2023Elevating Water Purification: The Essential Role of Water Purifier Pumps
18 Aug 2023Engineering Excellence: The Dynamics and Applications of Diaphragm Booster Pumps


This sub section presents the annual flow patterns together with the long term mean annual flow for selected stations within the Nile. Again this has been presented per Sub-basin and it follows the Sub-basin presentation sequence similar to the previous section.
The long-term annual flows are shown in the charts. The part of the Main Nile downstream of the High Aswan Dam is fully regulated and, therefore, the flows there are controlled releases for various uses in Egypt. The part of the Nile upstream of the High Aswan Dam is partially regulated by the dams in Sudan. The Nile in this sub-basin is highly altered in its flows due to the abstractions of water for various uses and the flow records no longer represent natural flow conditions. The long-term flow at the Dongola station is about 72 BCM. The average discharge of the Nile into the Mediterranean Sea through its two branches in Egypt is estimated as 10 – 12 BCM per year.


Power system transmission and distribution technology to the development of high voltage, large capacity, long distance, but also to promote the continuous development of high voltage switches. With a different period of development of power system, manufacturing enterprises will produce different off performance of high voltage switch to meet the needs of the power system, at the same time, the match of the operating mechanism of the development and application will have a significant impact. Due to the increase of operating power, the large capacity high voltage switch will be used to match the hydraulic operating mechanism. Therefore, how to do a good job and design a new type of hydraulic mechanism has become a major issue.
Discussions and we should pay attention to several cases of the hydraulic operating mechanism design as many designers generally focus on whether the system to meet the mechanical movement characteristic and disconnect, energy comprehensive utilization, and some minor aspects is easy to be neglected, many problems easily ignored in the initial design personnel, now according to the hydraulic mechanism of years design experience and actual discovery problem is presented.
1. Problems Should Be Paid Attention To In Design Of Hydraulic System
Selection of motor power
The formula of motor power is usually chosen:
N = P1 Q/η
P1: Pressure required to operate the system load;
Q: Flow rate of oil pump plunger;
η: Volumetric efficiency
Design and calculation of the maximum working pressure of hydraulic system:
P1 = F/ A
F: Maximum load force;
A: Hydraulic cylinder action area.
The pressure as a safety valve set pressure, thus ignoring the pipeline along the way loss and control valve system of local loss. Especially when the pipeline is longer or system memory in the greater resistance of the control valve or the synchronous valve, pressure loss is can not be ignored. Otherwise, actual pressure cylinder of a simply not up to the actual required, and the motor as power calculation is not accurate and not work reliably, thereby leading cause fever, resulting in the decrease of insulation capability and burn out, so the choice of the motor power should be according to the formula
N = (P1 + △P) Q/η
P: The pressure loss in system
P = P1 + P
When we were designing a product in our company, due to the neglect of the hydraulic system pressure loss, just according to the normal pressure consider the load of the working cylinder, calculate the motor power is relatively small, and simply with smaller power of the motor is working pressure, the motor running time is too long, lead to the oil pressure cannot establish suitable condition, near the heating of the motor, the consequences are from about 30% of the motor burned out, there is no damage to the motor insulation
Ability also drops. After the re calculation, select the appropriate motor replacement, after several twists and turns to ensure the reliable use of users.
2. Filter Flow Selection
The working capacity of the filter is determined by the effective filtration area, the performance of the filter, the viscosity of the oil, the pressure difference before and after filtration, and the content of solid particles in oil.
Whether the normal work flow filter selection in relation to the hydraulic system, individual designers to choose the filter flow, because the choice is not suitable, just choose the is about 2 times the normal work flow, work as the filter is satisfied that the sewage capacity is small, easily blocked, resulting in the work flow is reduced. Therefore, the design should choose the filter flow of 3 to 5 times the normal flow of work, so that the filter pollution capacity increased, and the service life of the filter is extended.
3. Selection Of Air Filter Flow
Due to the high voltage switch used in hydraulic mechanism in debugging the prototype stage and began construction of pressure, hydraulic pump and shrill noise, also heat pump, check the pump suction port does not leak, no clogging of the suction strainer, at first thought is the pump itself quality doesn’t pass, connecting damage 2 oil pumps, after careful analysis, accident found the root cause of is air filter is chosen too small, the air cleaner to fuel tank ventilation flow rate is less than the pump suction flow. So in the choice of air filter, should pay attention to the ventilation flow should be at least greater than the pump oil absorption. Especially the multi pump system should pay attention to this problem.
4. Valve Before And After The Pressure Difference
When using the throttle valve or pressure reducing valve in the system, when the valve before and after the pressure P2 P1/ > 315, easy to produce cavitation phenomenon, the performance of the valve noise, the system vibration and seriously shorten the service life of the valve
5. The Smooth Flow Of The Oil Drain Pipeline Of The Pressure Relay
Pressure relay is switch hydraulic mechanism often speak of the pressure switch, structure, mechanical and electrical equipment is composed of two parts, in the mechanical part is mainly composed of a piston, a spring, a safety valve, electrical parts is mainly micro switch component. Pressure relay need to discharge oil pipeline, the pipeline should not have any resistance, also should not and large flow valve components of the oil return common line, otherwise due to pressure fluctuations and other reasons, the pressure relay easily mistaking signal and does not move. Pressure relay adjustment of a product range is 25 ~ 27 MPa, less than 25 MPa when the pump starts to run, higher than 30 MPa when the safety valve leakage, the pump stops running. But because of the pressure relay drainage pipeline design is not appropriate, the pressure relay often false signal. Low-voltage sometimes 26 MPa, high pressure sometimes 2615 MPa, signal and lower, sometimes greater than 27 MPa signal, cause misunderstanding to run, so the pressure relay leakage oil pipeline must be smooth, in order to make the normal work
6. Oil Pump Oil Drain Pipe Routing
CY pump output shaft end sealing bearing compressive stress only 0.2 MPa, once the leaks oil pipeline processing is undeserved, the choice is too thin, there will be damaged seal, from the end of the output shaft appear the phenomenon of large-scale hydraulic oil splash, design for oil pipeline relief, first choosing the diameter to the right. Secondly, line as far as possible the use of less pressure loss of the valve.
7. Properly Designed Sealing Device
Hydraulic transmission is to rely on the volume of the seal to establish the pressure, transmission efficiency. Seal failure, in the zone pressure leakage and pressure loss, lower volumetric efficiency of heat to the system, sometimes oil leakage also soiled equipment (high voltage switch hydraulic system does not allow leakage), in the negative pressure area caused by vacuum suction; sealing over, although can prevent oil leakage, but increased friction intensified seal wear and shorten the life span. Therefore must be properly designed sealing device.
Sealing performance is good or bad is related to many factors, groove size is not correct; contact surface roughness is too low; sealing the gap value had great; improper use and maintenance; assembly rough and seals use unreasonable etc. will be causing leakage, the leakage problem from many aspects to analyze. In the selection of a seal, in addition to ensure good performance, must also have a longer life span period, in order to correctly select the required seal must familiar with the form and characteristics of various sealing, the sealing properties of the material and the use conditions (such as: work pressure, working environment temperature is high or low, part of the motor speed, lubrication, etc.) after comprehensive consideration.
Sealing device quality directly affects the work quality of hydraulic system:
(sealing device that is including: sealing, groove, a retainer ring and a supporting ring relevant parts are combined to form the sealing mechanism).
Therefore, the sealing device should have a basic requirement:
1) working pressure has good sealing performance, and with the increase of pressure can automatically improve the sealing performance, that is, there is no significant increase in the leakage under high pressure.
2) sealing device for the friction of the moving parts to be small, friction coefficient
To be stable, so as to avoid the movement of the phenomenon of stagnation or uneven movement of the card.
3) the wear is small, the working life is long.
4) manufacturing is simple, low cost, easy to install and maintenance.
8. Avoid Hydraulic Shock
In the hydraulic system, the hydraulic oil pressure caused by some kind of reason suddenly rises abruptly at a certain instant, which forms a very big pressure peak. The instantaneous pressure peak of the hydraulic shock is several times higher than that of the normal pressure, which is easy to cause the malfunction of the hydraulic equipment and affect the normal operation. My company in a hydraulic mechanism is a new and improved, due to the oil pressure of the high-pressure oil leads directly to the pressure relay without damping measures, to suppress the end of, causing the pressure relay micro switch repeatedly moves up and down, originally thought is a problem of pressure relay, after the careful analysis, instead of the pressure relay leading to the middle of the high-pressure oil pipeline increased buffer device. Finally, the problem was solved.
The above points are the author’s experience in the design of hydraulic system, for the peer discussion, in order to attract attention in the design. Of course, there will still be a lot of problems in the actual design, which requires high voltage electrical manufacturing industry counterparts to jointly solve the progress, to ensure that the design of the high voltage switch hydraulic system to further improve.


1080-Y03-C Jay R. Smith 3" Roof Drain - Water Dam Type
Used in flat roofs of any construction where a constant height of water is desired on the roof. It may also be used as an emergency overflow for conventional roofs, draining rain water when the depth of the water on the roof reaches the water dam height.
- Underdeck Clamp
- Overflow Drain - Water Dam Type


There is great potential for hydropower in Georgia, and this natural resource is likely to be increasingly utilised for power generation in the future. With the escalating demand for energy, government authorities are keen to harness renewable energy from the country’s main rivers. Often these projects aim at remote communities for which connecting to the national power grid is expensive. Hence, local hydropower production is an attractive and sometimes viable option. Critical is to conduct accurate feasibility assessments for hydropower generation at the different potential sites of interest considering climate change impacts. This work is a glacio-hydrological assessment of the expected river discharge at the planned hydropower sites in the Mestiachala river, Georgia.
Based on the requirements of the project, the Spatial Processes in Hydrology (SPHY) cryospheric-hydrological model was selected for the assignment. SPHY is a hydrological model that simulates the runoff at any location within the basin at a daily timescale. SHPY is ideal to assess glacier and snow influence in the river discharge and evaluate the impact of climate change. SPHY was used to predict the river discharge for the extended period of record and provide enhanced flow duration curves for hydropower assessment. In addition, total runoff components were quantified such as snow and glacier runoff.
This glacio-hydrological assessment delivered river discharge estimates for intake locations of two planned runoff river hydropower plants near Mestia, Georgia. The assessment included the calibration of a hydrological model, daily river discharge simulation for an extended period of record (1980-2015), climate change scenarios, and the derived flow duration curves to evaluate the flow operation of hydropower turbines. In addition, total runoff components were quantified such as snow and glacier runoff.
The daily river discharge was simulated at the two intake locations for two future periods (for the end of the concession period and for the end of century period) considering two climate change scenarios (RCP4.5 and RCP8.5). Hydrological model simulations were developed using future precipitation and temperature predictions and future glacier extent predictions. The climate change scenarios provide an evaluation of flow operation uncertainty. The daily flow calculations for the two sites can be used in the hydropower calculations, and to assess the overall profitability of the planned investment, taking into account energy prices, demand, etc.


Hydraulic cylinders are essential pieces of hydraulic engineering equipment. They are considered as common as pumps and motors combined, so if a hydraulic cylinder fails it can impact your entire operation. Minimising cylinder failure within hydraulic systems is important to avoid unnecessary lengthy equipment down time.
It is often stated that up to 25% of mechanical equipment failures are failures of design. If we apply this to hydraulic cylinders, as many as one in four hydraulic cylinders are not adequately designed for the given application they operate in. This does not mean that the cylinder is not capable of doing the job asked of it, it will usually, but not with an acceptable service life. If you are experiencing a particular hydraulic cylinder requiring frequent repair, you may need to address one or more design-related issues.
Bent rods are a common cause of rod seal failure. Bending of hydraulic cylinder rods can be caused by insufficient rod diameter or material strength, improper cylinder mounting arrangement or a combination of all three. Once a rod bends, excessive load is placed on the rod seal resulting in premature failure of the seal. we have the engineering expertise to calculate the permissible rod loading for cylinders in existing and new applications.
Ballooned Barrel Tubes
Ballooning of cylinder barrel tubes is usually caused by insufficient wall thickness and/or material strength for the cylinder’s operating pressure. Once the tube balloons, the correct tolerance between the piston seal and tube wall is lost and high-pressure fluid bypasses the seal. This high fluid velocity can result in erosion of the seal including localized heating caused by the pressure drop across the piston thus resulting in reduced seal life.
Insufficient Bearing Area
The internal bearing areas in the gland and at the piston are critical in carrying the thrust transferred to the cylinder. Insufficient internal bearing areas will result in excessive load being placed on the rod and piston seals. This results in deformation and ultimately premature failure of the seals.
The surface finish of the cylinder rod can have a dramatic effect on the life of the rod seal. If the surface roughness is too high, contaminant ingression is increased and an unacceptable level of leakage can result.
In the context of extending hydraulic cylinder service life, consider the surface of the cylinder rod as a lubricated wear surface and treat it accordingly. The installation of a boot to protect the rod surface and seals from impact damage and contaminants can also aid in extending cylinder life.
Regular Service & Maintenance
Regular service and maintenance of hydraulic systems is essential for removing contamination that will aid in the smooth running and longevity of major hydraulic equipment especially hydraulic cylinders.Datong Hydraulic has a dedicated team of service technicians that can aid in servicing and maintaining hydraulic systems to ensure cylinders continue to work to perfection.


1996 Volume 36 Issue Suppl Pages S190-S193
The control of molten steel flow in continuous casting molds is essential to increase the casting speed and produce clean steel. This requires accurate calculation of the velocity of the molten steel flow. Since there is no reliable velocimeter, water model experiments and numerical simulations have been carried out to predict this velocity, however, no experimental confirmation of such predictions has been made in a practical situation. In this study we developed a probe capable of measuring the velocity of a molten steel flow. The measurement principle is based on the linear relation between the shedding frequency of Kármán's vortex streets generated behind a circular cylinder and the velocity of fluid flow approaching the cylinder. The fluid flow velocity can be determined by measuring the oscillation frequency of the cylinder because the cylinder oscillates at the same frequency as the shedding frequency of Kármán's vortex streets.


Beijing: The Three Gorges Dam, China`s main reservoir built on Yangtze river last year, Tuesday passed its biggest flood control test by sustaining a massive water flow, greater than the 1998 floodings which claimed over 4,000 lives.
According to Xinhua, the flow on the river`s upper reaches topped 70,000 cubic metres a second Tuesday -- 20,000 cubic metres more than the flow during the 1998 floods that killed 4,150 people and the highest level since the dam was completed last year.
The flow peaked at 70,000 cubic metres per second at 8 a.m., still below the record high of 70,800 cubic metres per second in 1981, a senior official of the Three Gorges corporation said.
"The peak flow is high, but it has not exceeded the designed capacity of 100,000 cubic metres of water per second," said Cao Guangjing, the corporation`s chairman.
"The dam can withstand the challenge easily," Cao said.
At least 146 people have been killed and 40 were missing in 10 provinces till last week due to continuous rainstorms and floods since July 1, the ministry of civil affairs said Monday.
All ferry services were halted at the dam Monday and the 30-km exclusive road along the river had been opened to vehicles carrying shipping cargoes, said an official of the Three Gorges Navigation Administration.
Services would be resumed after the influx decreased from 70,000 to 45,000 cubic metres per second, the official said.
Ferries near the Gezhouba Dam, on the lower reaches of the Three Gorges, were still operating as the flow there was 40,000 cubic metres a second, below its designed capacity of 60,000 cubic metres per second, the official said.


An Experimental Investigation and Modeling of the Flow Rate of Refrigerant 22 Through the Short Tube Restrictor (NISTIR 89-4120)
D. A. Aaron, Piotr A. Domanski
Refrigerant 22 flow through short tube restrictors was investigated. The analysis pertained to initially subcooled refrigerant flowing through short tubes with 5 < L/D < 20. The flow conditions studied were those typically found in heat pumps. Flow dependencies upon upstream subcooling, upstream pressure, downstream pressure, tube length, tube diameter, entrance chamfering and exit chamfering were examined. A correlation and flow charts for mass flow rate prediction were developed from a large experimental data base. For a given inlet pressure and subcooling, the flow behaved differently depending upon the downstream pressure level. For downstream pressures greater than the approximate liquid saturation pressure of the entering refrigerant, the flow was strongly dependent upon the downstream pressure, as is found for single-phase fluid flowing through a duct. However, for downstream pressures below the saturation pressure, as is typically found during heat pump operation, the flow demonstrated a very weak dependence upon the downstream pressure and could be termed as non-ideal choked flow. For the case when the downstream pressure was below the saturation pressure, the mass flow rate was directly proportional to upstream subcooling, upstream pressure and cross sectional area, and was inversely proportional to short tube length. The mass flow rate was highly sensitive to inlet chamfering and insensitive to exit chamfering.
and Domanski, P.
An Experimental Investigation and Modeling of the Flow Rate of Refrigerant 22 Through the Short Tube Restrictor (NISTIR 89-4120), NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NIST.IR.89-4120, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=910660
(Accessed December 2, 2023)


120 million gallon water reservoir opens in Dubai
The Dubai Electricity and Water Authority (DEWA) completed the water reservoir at Al Lusaily, which will increase the emirate’s total water reserves to 790 million gallons.
“The project includes building two reservoirs with a storage capacity of 120 million gallons of desalinated water. This will strengthen the water network and increase water storage capacity in different parts of Dubai,” said Saeed Mohammed Al Tayer, managing director and chief executive of DEWA.
“The first reservoir is expected to be completed in December 2014, at a capacity of 60 million gallons, and the second in January 2015 at the same capacity.
“The completion of this project will increase the total storage capacity of DEWA to 790 million gallons compared to the current capacity of 670 million gallons.”
Published: December 7, 2014 04:00 AM


Water well pressure tank hook upUri 15/10/2018 2:56:49
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Laira Rail Depot – Water Penetration within Bunded area
Tidal water penetration through construction jointing within bunded area.
Resin injected TamPur 150 single component hydrophilic polyurethane through fixed packers where the water ingress
Was present during high tides, on completion of seal install a marine-based cementitious fillet over the injected perimeter areas, Reinstate arbokol polysulphide expansion join
Resolved water penetration providing a dry bunded area.
TamPur 150 , Flexcrete Marine Mortar S, Arbokol AG2 Polysulphide sealant.
Date completed: July 2020


How to disassemble a hydraulic cylinder?
An in-depth guide on how to disassemble hydraulic cylinder hydraulic cylinder, safety measures to be taken while conducting the process Hydraulic cylinder which are used in hydraulic systems plays a vital role in any hydraulic system. Since hydraulic cylinders does most of the task which could not be done manually or which is impossible that […]
Application Of Hydraulic Power Pack
There are a variety of uses for hydraulic power packs, including the following: if you are looking for hydraulic power pack manufacturers in india get in touch with canara hydraulics Application of hydraulic power pack machines Manufacturing: Used in the pressing, punching, and stamping processes that are part of the manufacturing process. Used in the […]
What is hydraulic power ?
What is Hydraulic Power Pack ? A hydraulic power pack is a device that can generate and store hydraulic energy for use in hydraulic systems. This energy can then be utilized by those systems. A pump, a motor, a reservoir, and a control valve are the typical components that make up this system. Are You […]
What Is Telescopic hydraulic cylinder
In this blog, we are going to talk about telescopic hydraulic cylinders. Let’s begin with what a hydraulic telescopic cylinder is and how it works. It is a special kind of acting cylinder or pneumatic cylinder which provides a longer output channel with a very less compacted retracted length. If you are looking for hydraulic cylinder […]
Top 5 Advantages of using A Single Acting Cylinder
In this blog, we are going talk about the advantages of using a single acting cylinder since hydraulic cylinder comes in various types single act cylinders, Double act cylinders, Tandem hydraulic cylinders, and telescopic hydraulic cylinders; different cylinders as different applications and different sizes. We are going to speak about one of the most important […]
Top-10 Benefits of hydraulic cylinders
What is an hydraulic cylinder? In this blog we are going to learn the benefits of hydraulic cylinder, It is used to gain linear force which comprises hydraulic fluid these hydraulic cylinders are used in various applications such as to Steel Mill, Material Handling, Machine Tools, Automation, Hydraulics Process, etc. Most of industrial machines worked […]
working of hydraulic cylinders
On What Principle? In this Blog we will be understanding the working of hydraulic cylinders and it’s principles working of hydraulic cyinder is based on Pascal’s principle is the foundation for how a hydraulic cylinder is supposed to work. Pascal’s principle states that the amount of pressure exerted is proportional to the force exerted divided […]
common hydraulic cylinder piston rod problems
Nature of issue Before we start talking about Hydraulic Cylinder Piston Rod Problems The most important thing is to be aware of the most frequent issues and how to fix them because no piece of equipment lasts forever and hydraulic cylinders are no exception. Some issues can be resolved quickly, while others may require extensive […]
How does hydraulic cylinder help in repairing work?
This Blog Is on How hydraulic cylinder helps in repair work ? And When To Repair ? And common methods for repairing a hydraulic cylinder When well cared for, hydraulic cylinders should last decades. So long as they were designed for their application — meaning they perform within the bounds of their environment — there […]
Common Causes of Hydraulic System Heat Contamination
In this Blog we are going to tell about common causes of hydraulic system heat contamination and tips to prevent overheating in hydraulic systems. Let’s Get Started Problems with heat contamination in hydraulic systems can be brought on by a variety of different factors. Due to the fact that heat loading problems can be caused […]


The driving device is used to drive the concrete storage tank to rotate. It is composed of power takeoff, universal shaft, hydraulic pump, hydraulic motor, control valve, hydraulic oil tank and cooling device.
If this part stops working due to failure, the concrete storage tank will not rotate, which will lead to the scrapping of the concrete in the vehicle, and even the whole tank of concrete will condense in the tank, resulting in the scrapping of the concrete mixing truck.
Therefore, whether the driving device is reliable or not is a problem that must be paid great attention to in use. In order to ensure the integrity and reliability of the driving device, the following maintenance work shall be done:
a. The universal rotating part is a fault prone part, so the lubricating grease shall be filled on time, the wear shall be checked frequently, and the parts shall be repaired and replaced in time. The fleet shall have spare cardan shaft assembly to ensure that it can resume operation within tens of minutes in case of failure.
b. Ensure that the hydraulic oil is clean. The working environment of concrete mixer truck is bad, so it is necessary to prevent dirty cement sand from entering the hydraulic system. The hydraulic oil shall be replaced regularly according to the requirements of the operation manual. Once water or sediment is found in the hydraulic oil during inspection, stop the machine immediately to clean the hydraulic system and replace the hydraulic oil.
c. Ensure that the hydraulic oil cooling device is effective. Clean the hydraulic oil radiator regularly to prevent the radiator from being blocked by cement. Check whether the electric fan of the radiator operates normally to prevent the hydraulic oil temperature from exceeding the standard. As long as the hydraulic part keeps the hydraulic oil clean, there are few general faults; However, different manufacturers have different service life.


Working principle of hydraulic shear fork lift platform
The working principle of the hydraulic shear fork lifting platform is that the motor directly drives the hydraulic pump, and the output pressure oil directly drives the hydraulic cylinder through the control valve, and drives the scissors mechanism to make the lifting platform move up or down. The hydraulic fork lift platform has the advantages of compact structure, smooth operation, small noise, fast frequency, high transmission power and easy operation. The hydraulic station, such as motor, hydraulic pump, oil tank and so on, has large noise when used, but it can be far away from the mainframe installation, and the noise and noise reduction treatment can be carried out separately. Because there are many kinds of hydraulic control valves, hydraulic system complex, difficult installation and cleaning pipe, high requirements for hydraulic oil quality of medium, and the hydraulic system is easy to spill (due to the use of hydraulic components of quality and cheap and lack of maintenance, the common hydraulic station around is oil) effect and high manufacturing cost factors.
Add：InTime Center,No.1600, Kejiguan Road,Binjiang District,Hangzhou， Zhejiang province, China.


Installation of a huge water tank and a gantry crane at the Amuza Itoman factory
It is being assembled to complete a huge water tank and a gantry crane to test new submersible in the factory.
Small-type high pressure test tank arrived at Amuza Itoman factory
A small-type high pressure test tank for water pressure testing of small parts has arrived. In addition to lar […]


Nilgiri I and II Hydropower Project will add 109 MW of electricity to national grid from coming October.
The work of 38 MW Nilgiri-1 and 71 MW Nilgiri-2 hydroelectric projects under construction on Nilgiri River has reached its final stage. Nilgiri Khola Hydro Power Limited has been working on both projects since 2076.
About 80 per cent work of the Nilgiri hydropower project, under construction in Annapurna Rural municipality-4, Narchyang of Myagdi district, has been completed.
Project Engineer Keshav Wagle said that the construction of both the projects is being completed within the next 6 months. "Constructing the project at the foot of the Himal was a big challenge for us", he said, "We managed to complete the project by dealing with all the challenges and problems.”
Promoted by the Nilgiri Khola Hydropower Company Ltd., Nilgiri Khola-I & the -II Hydroelectric Project have capacity of 40.7MW & 71MW respectively.
The electricity generated from the Nilgiri River will be connected to the Dana substation at a distance of 8.5 km through a 220 kV transmission line. The necessary transmission line work up to the substation is also being done. Out of the 24 towers of the line, 23 towers have been constructed and wire pulling work has been completed.
This is a big project in the district being constructed with private sector investment. The project took two years to build the access road in Akkare hill. The structures of the project have been built in the gorge of mountains.
According to the project, the dam site, tunnel digging and power house construction of both projects have been completed.
He informed that the work of penstock tunnel digging has been completed and the penstock pipe connection work of 800 meters of the Nilgiri-I and 1,500 meters of the Nilgiri-II has been started.
He informed that the civil structure work of the power plant to be built for both the projects has been completed and the electromechanical work has started.
A structure has been built in such a way that the water coming out of the Nilgiri-I power plant can be stored as a dam and put into the tunnel of the Nilgiri cascade.
A dam has been constructed at Humkhola and a power house at Chotepa on the Nilgiri-I. A 14-km access road has been constructed from cascade's power station to Humkhola.
Wagle said, "Constructing the project at the foot of the mountains was a big challenge for us, but we have been able to deal with all the challenges and problems, bringing the project construction to the final stage."
Both projects, estimated to cost around Rs. 16 billion, are of 'run-of-the-river' nature. Chairperson of Nilgiri Khola Hydropower Company Pvt. Ltd. Prithvi Bahadur Pande attended the headrace tunnel breakthrough of the Nilgiri Hydropower Project in July 2022.


In applications where a high flow rate is required, the pumps HenaLine series can be combined with the OktaLine series Roots pumps in modular design with numerous options.
- Designed for reliability, performance and ease of maintenance
- High pumping speed for fast evacuation times from 230 up to 1900 m3/h
- Higher pumping speeds on request
- CombiLine WU 232 with single-stage rotary vane pump Hena 60 and Roots pump Okta 250 (PPS22100)
- CombiLine WU 412 with single-stage rotary vane pump Hena 100 and Roots pump Okta 500 (PPS22101)
- CombiLine WU 942 with single-stage rotary vane pump Hena 300 and Roots pump Okta 1000 (PPS22103)
- CombiLine WU 1902 with single-stage rotary vane pump Hena 400 and Roots pump Okta 2000 (PPS22104)


As one of the most important inland rivers in China, the shortage of water resources and ecological deterioration of the Heihe River has increasingly attracted attention, and it is very significant to undertake the water resources sustainable utilization for its vulnerability assessment in the river basin. Using the pressure-state-response (PSR) model, a vulnerability index of the water resources system was developed and used to carry out a vulnerability assessment on the Heihe River in the current year (2010) and the comparison year (2003). The PSR of water resource vulnerability included 11 indexes, which are domestic water quota of urban residents, rural water quota of urban residents, million yuan GDP water consumption, per capita water consumption, ecological water proportion, drought index, per capita water resources, water modulus, water quality grade, water saving irrigation rate, per capita GDP, respectively. The vulnerability of water resources was evaluated by the attribute recognition model. The results show that water resources in the Heihe River Basin were in a quite vulnerable state in both 2003 and 2010 according to the values of scenario A1 (not vulnerable) and scenario B1 (severely vulnerable). It is urgent to protect and restore the water resources system in the Heihe River Basin.


Solar Water Pumps(JAL SHAKTI)
Solar water pumping systems are practical and affordable solution used to provide reliable and cost effective water supplies where there is no grid power or where power supply is unreliable.
“Solar Pumps operate anywhere the sun shines”
- System productivity increases in summer when water requirement is usually greater
- Require minimal service and maintenance
- Powered by clean, renewable energy
- Virtually free to operate, compared to the cost of diesel-powered generators and grid electricity which is constantly increasing
- Easily relocated to meet seasonal or variable location needs.
#Possible applications include:
- Livestock – cattle watering and fish farming
- Agriculture – irrigation or crop watering
- Recreational – swimming pool circulation pumps; spa
- Residential – water supply for drinking or pressure boosting
- Industrial – water supply for businesses
Water Pumping can be by submersible pumps, commonly used for deeper wells, where surface pumps cannot be used because the water level is too deep below ground level (below approximately 6 meters depth). These borehole pumps are specially designed to have a small outside diameter so they can be suspended below the water level in the well and connected to an output pipe that extends up to the surface.
The right pump for each application will depend on the required pumping rates and pumping height and distance.
Getting the most benefit from solar water pumping systems requires research and design before the first PV module and a pump is purchased and installed.
KLK Ventures Pvt Ltd. © 2019


Power at the Nozzle
Regardless of the size or type of pump or the size of its drive motor, the real measure of power output is the power at the waterjet nozzle. This is a direct function of the nozzle pressure and the volume flow rate through the nozzle, which can be expressed by the following formula:
HP = 0.58PQ
HP equals the hydraulic power actually delivered through the nozzle in units of horsepower
- P is the water pressure at the nozzle in units of thousands of pounds per square inch (for example, use 55 for 55,000 psi). This can usually be closely approximated by the pump output pressure, but watch out for systems that try to operate relatively large nozzle orifices (say greater that 0.014”) using relatively long runs of ¼” ultra-high pressure tubing with many fittings. The pressure drop between the pump and the nozzle for such systems can be several thousand psi.
- Q is the volume flow rate through the nozzle, in units of gallons per minute
- The constant of 0.58 accounts for the units of measure being used in the equation.
This simple equation makes two things very clear:
- The size of pump motor and the exact design and brand of pump are not in the equation. All that really matters in determining true nozzle power are the nozzle pressure and the volume flow rate
- Both pressure and volume flow rate are in the equation and have equal effect. Power at the nozzle can be increased by increasing pressure or increasing volume flow rate or a combination of both.
So the next time you are trying to compare ultra-high pressure pumps, ignore the size of the drive motor shown on the manufacturer’s spec sheet. Go further down the spec sheet and find the values of the recommended continuous operating pressure and the corresponding output volume flow rate. Then grab your calculator and determine for yourself the actual effective output power.


Cleghorn Water System Improvements
Cleghorn, IA | Water
Putting ingenuity to work for the City of Cleghorn (the City), ISG’s multi-disciplinary team provided cost-effective analysis and design for critical water solutions, while collaborating with the community on branding for the new water tower.
The City had been battling low water pressures and flows for years, affecting water quantity, quality and efficiency.
Through careful analysis and planning, the City approved the design and construction of a new 50,000 water tower to improve water quantity and efficiency. ISG modeled the water system and provided improvement recommendations to provide optimum system pressure, water quality, and flow. With the understanding that the City intended to install a water salesman to provide increased revenue for the project, ISG’s plan met design standards to avoid contamination.
ISG oversaw the construction bidding and administration process and assisted the City in securing funding through a Community Development Block Grant. Additionally, the City also took advantage of ISG’s robust toolbox of added value services, utilizing the firm’s in-house branding resources to design a new logo for the highly visible water tank.


Hydraulic oil can for V32 engine (20L)
20L can for HP circuit on compatible for Husmann slow shredders any type of 22 L.
V32 hydraulic oil drum for HL (208L drum)
Vercom Parts 208 L hydraulic oil drum for HP circuit on Husmann mill all types (HL2, HFG5 etc ...).
Reducer oil and angle return for slow mills (20L can)
Reducer oil and angle return for Husmann HF type grinders (20L can)
5 L hopper reducer oil can for screens
Reducing oil (5L can) for Terra Select brand screeners.
Zinc-free hydraulic oil (20L can)
Hydraulic oil for diesel engines Zinc free


A pump is hardware that feeds energy to a fluid (e.g. Water) to flow through channels. Pumps are used, for example, to direct water out of the ground, to transport drinking or sewerage water over large distances in combined pipe networks or to discard water from polders. In any practical application, the pump needs to work with its best performance. It is also important to check that the flow rate and head of the pump are within the required specifications, which are normally presented as the Pump Characteristic curves. These plots play an important role in understanding the region in which the pump needs to be operated thus ensuring the life of the pump.
Pump Characteristic Curves
The performance of any type of pump can be shown graphically, which can be based on either the tests conducted by the manufacturer or the simulations done by the designer. These plots are presented as Pump Characteristic Curves. The hydraulic properties of any pump (e.g. Centrifugal Pump) can be described by the following characteristics.
- Q-H Curve
- Efficiency Curve
- Net Positive Suction Head (NPSH) Curve
The Q-H curve gives the relation between the volume flow rate and the pressure head, i.e. the lower the pump head, the higher the flow rate. Q-H curves are provided by the manufacturer of the pump and can normally be considered as simple quadratic curves.
This gives the relation between pump efficiency against the volumetric flow rate. The efficiency of the pump is directly associated with the running cost. Lower efficiency of a pump results in higher power consumption and, in turn, an increase in operating cost to run it. While selecting the pump, it has to be selected based on the Best Efficiency Point known as BEP. However, the pump needs to operate at various off-design conditions and it is preferable to choose the pump with a flatter efficiency curve if the pump is to operate at off-design conditions for a longer duration.
Net Positive Suction Head Curve
The Net Positive Suction Head (NPSH) curve provides information about the suction characteristics of the pump at different flows. At the suction side of a pump, negative pressures can occur due to drop in absolute pressure of the liquid below vapour pressure. This results in formation of bubbles which are carried along with the fluid. As the pressure increases in the pump, these bubbles collapse, resulting in an implosion causing a pitting action on the impeller and casing. This phenomenon is known as cavitation. Even though the cavitation inside a pump cannot be completely avoided, it should be limited as much as possible. A pump should operate in such a way that the available NPSH is always higher than the required NPSH so the excessive cavitation in the pump can be prevented.
To maintain a strategic distance from cavitation, the available NPSH should be larger or equal to the required NPSH. The available NPSH is defined as:
NPSH available = Ha + ho – hv Here, Ha = Suction head at the impeller
ho = Atmospheric pressure
hv = Vapour pressure
Ha = h + V2 / 2g Here, h- pressure at the impeller entrance
V- Velocity of the water at the impeller entrance
How to Generate Pump Curves
Pump curves can be generated by reading measurements of pressure, NPSH, power, efficiency and others, while the pump is operating at different flow conditions. These results are then plotted against the flow rate to generate the pump characteristic curves. This method is useful for pumps in operation, but not entirely helpful for design purposes. Luckily, there is a way to generate these pump curves and more during the design process, to make sure the pump you need is the pump you get. AxSTREAM is the pump design and analysis tool that helps generate the pump characteristic curves. Using AxSTREAM, the pump can be designed from the known specifications as well as analyzed for different off-design characteristics. The performance curves can be generated during such analysis (see Figure 4). The calculations of AxSTREAM have been extensively validated with various experimental data helping the designers to produce these curves with very good accuracy.
One must be wondering how can these curves be utilized in a system design, for example, in designing a pumping station. AxSTREAM NET™ is the one-dimensional thermal fluid analysis tool of SoftInWay, which can be used for designing the pumping station. It consists of various other components apart from the pumps. The entire pumping station can be modeled inside AxSTREAM NET™ including several components such as valves, pipes, accumulators/reservoirs etc. The layout can be analyzed to simulate various situations. The performance characteristics generated in AxSTREAM, and incorporated in AxSTREAM NET™, helps to accurately predict the performance of the pumping station and to optimize it at the system level. A simple example of a pumping station, designed and calculated in AxSTREAM NET™, is shown in Figure 2.


Dam Erosion Protection
For over 70 years asphalt has been used to waterproof dams either as a core or as a lining. When placed as a lining the asphalt also provides protection against wave impacts.
On older UK dams a clay core or blanket within the dam embankment was often used to provide the waterproofing and the dam embankment required additional protection from wave attack. This was often provided by stone pitching, loose rock, or concrete blocks.
Hesselberg Hydro has worked with dam owners since 1991 to create innovative, cost-effective solutions to upgrade existing erosion protection systems and to provide new erosion protection for dam-raising projects.
Why is maintenance and development of existing dam structures important?
- Deterioration with age – many dams in the UK are over 150 years old
- Construction of new dams in Europe is a very lengthy and controversial process
- Increasingly strict statutory controls for flood tolerance
- Climate change may impose greater pressure on water supply
- Erosion of reservoir banks
- Settlement of existing linings and barriers
- Weakening of upstream faces by wave attack and weathering
- Undermining of pitching/blockwork following wash-out of bedding material
- Spillways need to withstand greater discharge volumes
Please click on the links below to review recent projects:
- OSA to strengthen Stone Pitching
- Grout to strengthen Rock


Control of the mixer during the operation depends on the type of hydraulic drive system used. If the regulator on hydraulic pump used for mixer drive is a mechanical type, then the simplest and most durable solution used by IMER is to control the operation of the mixer through a control cable driven by a lever mechanism.
The lever control itself is located in the back of the machine on the left hand side near the ladder.
The operation of the mechanism can be carried out by setting the mixer rotation speed and changing the direction: mixing – unloading.
In case of electro-hydraulic control for the hydraulic system the operation is performed via electric panel. It has the functions of changing the speed of concrete mixer rotation and changing the rotation direction.


SHILLONG, July 12 - North Eastern Electrical Power Corporation (NEEPCO) in a press statement issued today has claimed that had Ranganadi Dam not been there, the downstream situation could have been worse.
It further said that the same situation occurred in 2008 when various Committees had visited the site and agreed that this is a natural phenomenon and not connected to NEEPCO.
The release clarified that the 405 MW Ranganadi Hydro Electric Project developed by NEEPCO on river Ranganadi in Arunachal Pradesh is a run-of-river scheme with a very small pondage. The full reservoir level of the Project is El 567.0 metre and it can store water upto this level.
The maximum discharge of 160 cumec of water from Ranganadi reservoir is utilised for hydro power generation which is eventually diverted to Dikrong river through tail race channel which helps in mitigating the downstream discharges. The excess water beyond the capacity of the reservoir flows in the downstream area. The reservoir provides cushioning effect in controlling the downstream discharges, the release said.
Due to the incessant torrential rainfall in the catchment areas of river Ranganadi since June 30, the inflow of water in the river increased substantially and achieved the maximum at 3 pm on July 9. After ultilising the water required for power generation, excess water, was spilled over through the gates of the dam in a controlled manner. It is important to mention that 200 cumec was utilised as power draft and retained within the reservoir, thus controlling the downstream discharges. The natural flood occurring in the upstream of the Project cannot be absorbed by the reservoir only, according to the release.


It is rock fill dam with mud core, high 113m its length with the spillway is 3650m, top width 10m as shown in photograph.
The surface area of its reservoir is 380km2 with a storage capacity of 11.11 billion m3 at operation level 330m above sea level. The dead and live storages are 8.16 2.95 billion m3 respectively.
Sediment load of the River Tigris are deposited within the reservoir. Coarse particles are deposited once the river enters the reservoir while fine sediments are deposited within the vicinity of the dam. In all cases the deposition of the sediment reduces the capacity of water storage within the reservoir.
The goal of this research project is to estimate the quantity of sediments deposited within the reservoir since its operation to find out the reduction of storage within the reservoir. Furthermore the distribution of the sediments will be investigated. In addition data will be also compared with a physical model of the upper part of the reservoir that exists at Mosul University. Suggestions are to be given to minimize the Siltation of the reservoir.
PhD student: Issa Elias Issa
Supervisors: Sven Knutsson, Nadhir Al-Ansari


Hugh Keenleyside Dam
History and hydroelectric operation
Hugh Keenleyside Dam, 8 km (5 miles) upstream from Castlegar, was the second of three Columbia River Treaty dams to be built by BC Hydro. The Columbia River Treaty allowed construction of dams to regulate the flow of the Columbia River and end the annual threat of flood damage in B.C., Washington and Oregon.
Additional benefits were increased power generation at existing power plants and the development of large power plants at several locations along the Columbia and its tributaries.
The earth fill and concrete structure was declared operational on October 10, 1968, nearly six months ahead of schedule. The dam is about 52 m (171 feet) high, with a crest length of 853.4 m (2,800 ft.). 366 m (1,200 ft.) of the crest length is concrete dam and the rest is earth fill dam.
Keenleyside Dam controls a drainage area of 3,650,000 ha (14,100 square miles). It holds back a storage reservoir (the Arrow Lakes) extending 232 km (145 miles) north to Revelstoke. Release of the 8.8 billion cubic m (7.1 million acre-ft.) of live storage is controlled by four sluice ways and eight low-level ports.
In 2002 the provincially owned Columbia Power Corporation completed construction of a 185 MW powerplant adjacent to the dam.
Keenleyside navigational lock
The Hugh Keenleyside Dam navigational lock is available for all properly equipped watercraft. There is no charge for use of the lock; however, weekday passage may be delayed because of the need to pass commercial traffic and logs downstream of the dam. Commercial traffic will have priority in all cases over pleasure craft.


Automatic Selfcleaning Water Filters
|Min. Order (Sets)||FOB Price|
|1+||US $3,000 / Set|
Self-cleaning filtersbackwash filters
Automatic pressure filters
Industrial Waste filters
High purity filters
Circulating water filters
Emulsion regeneration filters
Treatment of waste oil filters
Blast furnace water systems with high pressure water rolling
Metallurgy casting water system
1\The filter-type gear reducer with NRV, adopt high quality aluminum alloy die casting shell structure, good heat dissipation, noise, light weight, large carrying capacity.
2\seal enhanced with CV62.1-85 standard PTFE double seal structure, reliable sealing performance, long life and tight.
3\top with exhaust valve, compact, open and close sensitive.
4\Pressure control system D520/7DD adjustable differential pressure controller switching differential, the signal feedback is correct, sensitive.
5\ Multiple filter structure, the effective filter area, pressure drop, high efficiency backwash.
6\ flower plate of stainless steel filter, and anti-work interface mirror suction flushing handle.
7\use of PTFE suction backwash backwash from the whole structure and organization, to ensure that sucker with a long-term filter tubesheet seal, enhanced anti-wash effect.
8\ Electrical control system PLC programmable controller, cleaning mode with differential pressure control, timing control and manual control in parallel mode, cleaning mode with time positioning mode, backwashing flow is small, anti-wash thoroughly.
9\Backwash flow continuously when
2\circulating water filter
4\Treatment of waste oil filter
5\metallurgy casting water system
6\blast furnace water systems with high pressure water rolling
The filter from the housing, multi-filter, backwashing agencies, electric control system, power plant, electric discharge valve and differential pressure control system. Spent within the filter housing cavity plate will be divided into upper and lower chamber, the chamber is equipped with multiple filters, so make full use of space, significantly reduces the filter size, installed under the anti-cavity; In the wash sucker. Work, turbid liquid filters through the entrance, but also by the flower into the filter cavity plate hole, the impurity is greater than the filter pore closure, the net fluid through the filter pores to reach the chamber from the exit out.
When the filter impurities accumulate in the filter pressure drop caused by increased surface to the desired value, or timer to preset time, the electrical control system to signal, driving anti; In the body wash. When the filter backwash suction Handicap and imports are on, the drain valve open, then the system pressure relief discharge, suction and filter inside the emergence of a relative pressure lower than the pressure of negative pressure outside the filter area, forcing part of the circulating fluid lateral flow from the filter cartridge inside. Adsorption of impurities in the filter inner walls of the particles with the sewage flow into the suction valve inside and discharged from the sewage. Specially designed filter to produce jet filter effect, any impurities will be washed away. When the pressure drop back to normal or timer setting time has elapsed, the motor stops running, the electric discharge valve closed. Throughout the process, continue to stream flow, less anti-wash liquid consumption to achieve a continuous and automated production.
|Maximum flow||3000m 3||According to process requirements and design|
|Minimum working pressure||0.4Mpa|
|Maximum working pressure||1.6Mpa|
|Maximum working temperature||80|
|Backwash flow||Less than 1~2% of the total|
|Backwash Pressure||0.5Kg/cm 2|
|Filter Type||Drilling filter||Wedge filter||Woven filter|


In the graphic, at the top of the drawing, is a 5-ported, 2 position valve schematic. It depicts each one of its two cylinder port lines plumbed into the top of separate oil tanks, marked as A & B on the drawing.
More information on 5-ported, 2 position air valves is here in case you seek more information about this type of air valve.
Each oil tank has a line plumbed to supply oil from the tank to one of the ports on the cylinder at the bottom of the drawing. Each of those oil lines has a flow control in it.
The air over oil system uses compressed air introduced into the air tanks via the 5/2 air valve. The air from the valve is used to pressurize and drive the oil from each tank into the cylinder.
The flow controls in the lines to the cylinder will meter the oil as it exits each cylinder port. Since the oil is incompressible (as far as we are concerned) even though the air that is pushing on the oil may vary in strength and flow, the oil, being metered through the flow control, moves through the flow control consistently. This ensures a smooth, regular, same-speed stroke of the rod and the tooling every cycle, regardless of the fluctuations that occur normally in the compressed air supply.
The compressed air fills the top of the air / oil pressure tank, and then exerts force on the oil in that tank.
That oil then flows through the line to the cylinder port, causing the cylinder rod or carriage to extend or retract depending on which port it flows to.
The flow controls, one installed on each of the cylinder lines, will operate by restricting the flow of oil out of the cylinder, thereby dampening the flow of the oil resulting in a smooth, consistent stroking of the cylinder rod.
When the air valve is shifted in the other direction, the air flows down the other valve line to the other air / oil tank, and the cycle repeats.
Each time the valve shifts, the oil being driven into the cylinder from one tank pushes the cylinder piston towards the other end of the cylinder, and that piston drives the oil on the other side back up the line to the other air / oil tank.
A properly installed air over oil system as described will provide the cylinder stroke speed and consistency that you desire for your application.
Depending on the cylinder cycle speed, each time the valve shifts, a minute amount of oil may exhaust with the air. A re-classifier should be plumbed to the valve's exhaust port(s). This device will strip the exhaust air of oil for re-use or disposal.
Trying to drive an air - oil system at too high a speed could cause the oil to boil in the tank generating a significant amount of air bubbles in the oil, which will affect the systems control of cylinder speed and stroke time. It's best to run the circuit at the slowest effective and acceptable speed for the application.
Check with the air cylinder vendor to ensure that their cylinder can be used in an air-oil application. Most can. The pressures generated in an air/oil system are usually well within the safety factors for typical pneumatic cylinders.
You can use a hydraulic cylinder of course, but if the pneumatic cylinder works, it will be less costly than an equivalent hydraulic cylinder.
Each of the oil tanks must contain enough oil to fill the cylinder during a complete stroke (an extension or retraction) without completely emptying the tank.
The air valve is connected to the air/oil tanks, one working port to each tank.
The air lines are connected from the valve port to the fitting on the top of each air / oil tank.


Impingement split flow liquid-cooled microchannel cold plates are one of several flow configurations used for single-phase liquid cooling. Split flow or top-in/side-exit (TISE) cold plates divide the flow into two branches thus resulting in halved or reduced flow rates and flow lengths, compared to traditional side-in /side-exit (SISE) or parallel flow cold plates. This has the effect of reducing the pressure drop because of the shorter flow length and lower flow rate and increasing the heat transfer coefficient due to thermally developing as opposed to fully developed flow. It is also claimed that the impinging flow increases the heat transfer coefficient on the base plate in the region of impingement. Because of the downward impinging and turning flow, there are no exact analytical models for this flow configuration. Computational and experimental studies have been performed, but there are no useful compact analytical models in the literature that can be used to predict the performance of these impingement cold plates. Results are presented for novel physics-based laminar flow models for a TISE microchannel cold plate based on an equivalent parallel channel flow approach. We show that the new models accurately predict the thermal-hydraulic performance over a wide range of parameters.


Reinforced concrete core dams can be an alternative solution to conventional dam designs either for permanent impounded reservoirs or flood protection and flood-retaining dams. Dams of this type have been constructed in Austria for various reasons and have shown good behavior during operation. For a better understanding of the load-deformation behavior of this type of dams during construction and impounding, numerical simulations were carried out. The interaction between the thin reinforced concrete core and the dam fill material as well as the influence of fill material properties and other main parameters, such as the roughness of the concrete surface and bedding conditions of the concrete core, on the deformation behavior of dams were examined. The results show that high compressive stress is mainly induced by arching effects in the dam body during construction. During the reservoir impounding, the compressive stresses in the core are reduced significantly while the bending moment in the core footing increases. The results also show that the maximum bending moments occur at the core footing and can be significantly reduced by design improvements. The findings in this study can provide general design recommendations for small dams with a central concrete core as a sealing blanket.
Tschernutter, P., & Kainrath, A. (2016). Design considerations and behavior of reinforced concrete core dams during construction and impounding. Water Science and Engineering, 9(3), 212–218. https://doi.org/10.1016/j.wse.2016.11.006


Wood River Valley Groundwater Flow Model
The Wood River Valley Groundwater Flow Model Project was initiated to help provide a scientific foundation for the management of aquifers underlying the Wood River Valley. In 2008, the Idaho legislature approved House Bill 428 and House Bill 644 establishing the Statewide Comprehensive Aquifer Planning and Management Program (42-1779) and the Aquifer Planning and Management Fund (42-1780). This legislation authorized the Idaho Water Resource Board to begin comprehensive aquifer management planning (CAMP).
The Aquifer Planning and Management Program is designed to provide the Idaho Water Resource Board and the Idaho Department of Water Resources with the necessary information to develop plans for managing ground and surface water resources into the future. This phase of the program for the Wood River Valley will begin with the technical component of developing a groundwater flow model.
The Idaho Department of Water Resources and the United States Geological Survey (USGS) are partnering to develop a groundwater-flow model of Idaho’s Wood River Valley aquifer system. The project is anticipated to be completed in late 2015.
Purpose and Objectives
The model will be constructed to simulate the effects of climate and human activities on the aquifer system with an emphasis on the interaction of the surface and groundwater system. This work will incorporate the increased knowledge about the aquifer system which has been developed in the past several years. USGS reports can be found at the References tab. USGS staff has been working with local communities and organizations to gather information and analyze the aquifer system. This increased understanding of the groundwater system, described in several technical papers published by USGS, will be the base for the model development.
Groundwater-flow models are developed to represent our understanding of the aquifer system and can be used to manage and plan for the water needs and uses of the region. The Wood River Valley groundwater-flow model will be designed to further the basic understanding of the aquifer system and ultimately to examine effects on the groundwater system and its interaction with the Big Wood River due to changes in water use, recharge, or discharge.
A technical advisory committee will be established to provide the modeling team with input during the model construction.
Contact InformationSean Vincent
Idaho Department of Water Resources
Wood River Valley Aquifer Model:


Moreover, several studies [11, 12, 13] noticed that both water and sediment discharge
of several world' rivers have shown progressive decrease during the last 50 years, which is more primarily due to reservoir construction, water abstraction, and soil conservation.
However, these methods determine only an average flow velocity and the sediment discharge
in the floodplain as a whole.
The recent sediment cover on the Lisbon shelf is largely determined by sediment discharge
from the Tagus (Tejo) River, a major river draining an area of more than 80 000 [km.
The maximum sediment discharge
for BT usually occurred ~12 min after the start of the experiment, during which 16 mm of rain was applied to the plots, whereas the sediment discharge
in the ST and GT plots peaked 18-20min later (Fig.
Internal and external experts pronounced the water and sediment discharge
as nontoxic and biodegradable.
Related to the liquid debit, maximal value of sediment discharge
Similarly the exponential curve line have been developed on the water flow and sediment discharge
data, because the exponential curve lines are used when the data rise or fall.
Usually sediment discharge
into Sefidrud River starts in October causing reduction of DO in all stations.
Six appendices are included, containing descriptions of rock scour, riprap design, sediment transport scaling for physical models, methods for estimating sediment discharge
, a glossary, and conversion of units.
Consequently, this is also the peak sediment discharge
To place the estimate of total sediment trapped in context, the sediment discharge
record from the watershed was summarized.
Infrequent large storms can produce large quantities of stream flow and sediment discharge
, but some of the flow occurs on the floodplain adjacent to the channel.


Cold water feed surrounds the hot water to ensure the valve is safe to touch by all the family.
Fast fit connectors for easy retro-fit installation.
Pre-set to 38° C with push button override to 46° C.
Eco feature on flow control which can be overridden.
Suitable for all plumbing systems, preferably balanced.
15mm compression inlet connections.
Inlet centres at 150mm.
0.1 to 5.0 bar working pressure range.
19.4 l/min flow rate at 3.0 bar.
See the complete range of Bristan Frenzy
products, including complementary bathroom taps.


This article needs additional citations for verification. (September 2012)
A metering pump moves a precise volume of liquid in a specified time period providing an accurate volumetric flow rate. Delivery of fluids in precise adjustable flow rates is sometimes called metering. The term "metering pump" is based on the application or use rather than the exact kind of pump used, although a couple types of pumps are far more suitable than most other types of pumps.
Although metering pumps can pump water, they are often used to pump chemicals, solutions, or other liquids. Many metering pumps are rated to be able to pump into a high discharge pressure. They are typically made to meter at flow rates which are practically constant (when averaged over time) within a wide range of discharge (outlet) pressure. Manufacturers provide each of their models of metering pumps with a maximum discharge pressure rating against which each model is guaranteed to be able to pump against. An engineer, designer, or user should ensure that the pressure and temperature ratings and wetted pump materials are compatible for the application and the type of liquid being pumped.
Most metering pumps have a pump head and a motor. The liquid being pumped goes through the pump head, entering through an inlet line and leaving through an outlet line. The motor is commonly an electric motor which drives the pump head.
Some metering pumps can be used for dispensing. A metering pump is designed to deliver a continuous rate of flow, however, a dispensing pump is designed to deliver a precise total amount.
Many metering pumps are piston-driven. Piston pumps are positive displacement pumps which can be designed to pump at practically constant flow rates (averaged over time) against a wide range of discharge pressure, including high discharge pressures of thousands of psi.
Piston-driven metering pumps commonly work as follows: There is a piston (sometimes called plunger), typically cylindrical, which can go in and out of a correspondingly shaped chamber in the pump head. The inlet and outlet lines are joined to the piston chamber. There are two check valves, often ball check valves, attached to the pump head, one at the inlet line and the other at the outlet line. The inlet valve allows flow from the inlet line to the piston chamber, but not in the reverse direction. The outlet valve allows flow from the chamber to the outlet line, but not in reverse. The motor repeatedly moves the piston into and out of the piston chamber, causing the volume of the chamber to repeatedly become smaller and larger. When the piston moves out, a vacuum is created. Low pressure in the chamber causes liquid to enter and fill the chamber through the inlet check valve, but higher pressure at the outlet causes the outlet valve to shut. Then when the piston moves in, it pressurizes the liquid in the chamber. High pressure in the chamber causes the inlet valve to shut and forces the outlet valve to open, forcing liquid out at the outlet. These alternating suction and discharge strokes are repeated over and over to meter the liquid. In the back of the chamber, there is packing around the piston or a doughnut-shaped seal with a toroid-shaped sphincter-like spring inside compressing the seal around the piston. This holds the fluid pressure when the piston slides in and out and makes the pump leak-tight. The packing or seals can wear out after prolonged use and can be replaced. The metering rate can be adjusted by varying the strokelength by which the piston moves back and forth or varying the speed of the piston motion.
A single-piston pump delivers liquid to the outlet only during the discharge stroke. If the piston's suction and discharge strokes occur at the same speed and liquid is metered out half the time the pump is working, then the overall metering rate averaged over time equals half the average flow rate during the discharge stroke. Some single-piston pumps may have a constant slow piston motion for discharge and a quick retract motion for refilling the pump head. In such cases, the overall metering rate is practically equal to the pumping rate during the discharge stroke.
Pumps used in high-pressure chromatography
Pumps used in high-pressure chromatography such as HPLC and ion chromatography are much like small piston metering pumps. For wear resistance and chemical resistance to solvents, etc., typically the pistons are made of artificial sapphire and the ball check valves have ruby balls and sapphire seats. To produce good chromatograms, it is desirable to have a pumping flow rate as constant as possible. Either a single piston pump with a quick refill is used or a double pump head with coordinated piston strokes is used to provide as constant a pumping rate as possible.
Diaphragm and peristaltic pumps
In order to avoid leakage at the packing or seal particularly when a liquid is dangerous, toxic, or noxious, diaphragm pumps are used for metering. Diaphragm pumps have a diaphragm through which repeated compression/decompression motion is transmitted. The liquid does not penetrate through the diaphragm, so the liquid inside the pump is sealed off from the outside. Such motion changes the volume of a chamber in the pump head so that liquid enters through an inlet check valve during decompression and exits through an outlet check valve during compression, in a manner similar to piston pumps. Diaphragm pumps can also be made which discharge at fairly high pressure. Diaphragm metering pumps are commonly hydraulically driven.
Peristaltic pumps use motor-driven rollers to roll along flexible tubing, compressing it to push forward a liquid inside. Although peristaltic pumps can be used to meter at lower pressures, the flexible tubing is limited in the level of pressure it can withstand.
The maximum pressure rating of a metering pump is actually the top of the discharge pressure range the pump is guaranteed to pump against at a reasonably controllable flow rate. The pump itself is a pressurizing device often capable of exceeding its pressure rating, although not guaranteed to. For this reason, if there is any stop valve downstream of the pump, a pressure relief valve should be placed in between to prevent overpressuring of the tubing or piping line in case the stop valve is inadvertently shut while the pump is running. The relief valve setting should be below the maximum pressure rating that the piping, tubing, or any other components there could withstand.
Liquids are only very slightly compressible. This property of liquids lets metering pumps discharge liquids at high pressure. Since a liquid can be only slightly compressed during a discharge stroke, it is forced out of the pump head. Gases are much more compressible. Metering pumps are not good at pumping gases. Sometimes, a metering or similar pump has to be primed before operation, i. e. the pump head filled with the liquid to be pumped. When gas bubbles enter a pump head, the compression motion compresses the gas but has a hard time forcing it out of the pump head. The pump may stop pumping liquid with gas bubbles in the pump head even though mechanically the pump is going through the motions, repeatedly compressing and decompressing the bubbles. To prevent this type of "vapor lock", chromatography solvents are often degassed before pumping.
If the pressure at the outlet is lower than the pressure at the inlet and remains that way in spite of the pumping, then this pressure difference opens both check valves simultaneously and the liquid flows through the pump head uncontrollably from inlet to outlet. This can happen whether the pump is working or not. This situation can be avoided by placing a correctly rated positive pressure differential check valve downstream of the pump. Such a valve will only open if a minimum rated pressure differential across the valve is exceeded, something which most high-pressure metering pumps can easily exceed.
- The Ins and Outs of Metering Pumps Metering pumps offer a high degree of accuracy and are suited for water treatment, chemical processing and laboratory dispensing