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High Pressure Pumps for Desalination DHP4.5-8.2

High pressure pumps for desalination DHP4.5-8.2 are designed to transport high-pressure, low-viscosity corrosive fluids, such as high-pressure brine (seawater) in seawater reverse osmosis systems.

Based on the principle of swash plate axial piston pump, the DHP4.5, DHP5.3, DHP6.3, DHP7.2, DHP8.2 series high pressure pumps for SWRO work by using the volume change produced by the reciprocating movement of the piston parallel to the drive shaft in the piston hole, and use the fluid itself to lubricate the moving parts of the pump. This series of ro high pressure pumps is integrated with a check valve, which allows fluid to flow from the inlet to the outlet via the check valve when the electric high pressure water pump stops.

The high pressure desalinations pumps DHP4.5, DHP5.3, DHP6.3, DHP7.2, DHP8.2 series are fixed displacement pumps, and the flow rate is proportional to the speed of the input shaft and the displacement of the pump.
  • ro high pressure pump
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Overview


The reverse osmosis desalination pump DHP4.5, DHP5.3, DHP6.3, DHP7.2, DHP8.2 series are positive displacement pumps with 9-pistons that move a fixed amount of water in each cycle. The best high pressure water pumps are based on the axial piston principle enabling a very light and compact design. Flow is proportional to the number of input shaft revolutions(rpm). Unlike centrifugal pumps, they produce the same flow at a given speed no matter what the discharge pressure.


The DHP4.5, DHP5.3, DHP6.3, DHP7.2, DHP8.2 range of best high pressure water pumps is designed for use in RO applications with low viscosity and corrosive fluids such as: Sea water (in seawater reverse osmosis filtration applications), Brackish water (high-pressure saltwater pumping), Waste water.


The DHP4.5, DHP5.3, DHP6.3, DHP7.2, DHP8.2 series best high pressure water pumps are supplied with an integrated flushing valve that allows the salt water to flow from inlet to the outlet, when the pump is not running.


Advantages (Hot Sale High Pressure Water Pumps)


√ Simple structure, small size, light weight, one of the smallest and lightest pumps on the market

√ Low pressure fluctuation, high working pressure

√ If a special coupling is used, it can be driven by an internal combustion engine

√ No need for lubricating oil, long maintenance period, no preventive maintenance during the warranty period

√ The pressure pulse generated in the pressure pipe is extremely small

√ Integrated flushing check valve, no need for additional installation

√ All parts of the pump are made of corrosion-resistant materials such as duplex (SAF 2205 / EN 1.4462 / UNS 31803) and super duplex (SAF 2507 / EN 1.4410 / UNS 32507) stainless steel, and carbon fiber reinforced polyether ether ketone (PEEK)) production

√ Efficient


Technical Specification Sheet


Desalination Pump Specification DHP4.5 DHP5.3 DHP6.3 DHP7.2 DHP8.2
Geometric displacement cm3/rpm 50 63 70 80 100
Rated flow at 1500rpm, m3/h 4.5 5.3 6.3 7.2 8.2
Minimum outlet pressure, Bar 10 10 10 10 10
Maximum continuous outlet pressure, Bar 80 80 80 80 80
Maximum gap outlet pressure, Bar 100 100 100 100 100
Minimum inlet pressure, Bar 1 1 1 1 1
Maximum continuous inlet pressure, Bar 5 5 5 5 5
Maximum continuous speed, rpm 1800 1800 1800 1800 1800
Minimum continuous speed, rpm 700 700 700 700 700
Noise dB(A) ≤78 ≤78 ≤78 ≤78 ≤78
Power when rated speed 1500rpm and outlet   pressure 80Bar, kW 15 15 18.5 22 22
Weight, kg 34.5 34.5 34.5 34.5 34.5
Integrated flushing check valve YES YES YES YES YES


Flow rate at different speeds


If the required flow rate and speed (rpm) are known, it will be easy to select the most suitable pump by using the diagram below:


speed-&-flow-for-DHP4.5-8.2-high-pressure-pump


Not only that, the graph also shows that the flow rate can vary with the speed of the best high volume high pressure water pumps. The flow/speed ratio is fixed, and the required flow can be obtained by changing the speed to the corresponding value.


Power Requirement


MODEL FLOW PRESSURE SPEED
L/min m³/h 60Bar 70Bar 80Bar rpm
DHP4.5 75 4.5 11kW 11kW 15kW 1500
DHP5.3 88 5.3 11kW 15kW 15kW 1500
DHP6.3 105 6.3 15kW 15kW 18.5kW 1500
DHP7.2 120 7.2 15kW 18.5kW 22kW 1500
DHP8.2 136 8.2 18.5kW 22kW 22kW 1500


Inlet pressure


The desalination pump DHP series can directly supply water from the feed water pump, and the pressure of the water inlet of the ro high pressure pump must be within the range of 2-5Bar (0.2-0.5Mpa or 29-72.5psi).

Unit conversion relationship: 1.0Mpa=10Bar, 1.0Mpa=145psi


Temperature and corrosion


Best High Pressure Water Pumps Operation


Fluid temperature: +2°C ~ +50°C-depends on the concentration of NaCl

Ambient temperature: +2°C ~ +50°C


The following figure shows the relationship between the corrosion resistance of different types of stainless steel and the concentration of NaCl and temperature.


All key components of DHP series high pressure pump for seawater reverse osmosis are made of 2507.


If the desalination pump is running under conditions of high salt content, fresh water should be used to flush the ro high pressure pump during shutdown to reduce the risk of corrosion.


DHP0.6-1.0-High-pressure-pump-operation


Best High Pressure Water Pumps storage


Storage temperature: -40°C to +70°C (the ro high pressure pump has been emptied and sealed for storage).

Antifreeze is required when the temperature is lower than 2°C; It is recommended to use Dow Cal-N from DuPont Chemical Company or Chill safe Propylene Glycol from Ark man Chemical Company.


Noise


Under normal circumstances, the noise will be reduced when the speed is reduced, and vice versa. Flexible hoses can be used to minimize vibration and noise.

As the ro high pressure pump (group) is usually installed on a bell-shaped cover or base, the noise level can only be determined by the entire system. Therefore, the correct use of shock absorbers to install the pump set on the base is extremely important to reduce vibration and noise.

The noise level is affected by the following factors:

The speed of the pump, high speed produces more noise than low speed

The rigid installation of the pump generates more noise than the flexible installation

Compared with the connection through a hose, the direct connection of the pipe to the pump will increase the noise


Filtration


Because the viscosity of water is very low, in order to control the internal leakage rate and improve the performance of the components, the gap of the DHP series ro high pressure pump is designed to be very small. Therefore, proper filtration of inlet water is essential to minimize pump wear.

The main filter must have a filtration efficiency of 99.98% for particles above 10 µm. It is recommended to use a precision depth filter element with a rated accuracy of 10 µm (absolute accuracy) and ß10>5000 (equivalent to a filtration efficiency of 99.98%). Filter bags and wound filter elements usually only have a filtration efficiency of 90%, which means that for every 100,000 particles that reach the filter, 10,000 pass through. Relatively speaking, only 20 pass through a filter with an efficiency of 99.98%.


Dimensions


installation-dimensions-for-DHP-HP-Pump4.5-8.2


PUMP MODEL DHP4.5~DHP8.2
Flat key (mm) 10×8×40
Exhaust Plug 8mm inner hexagon
Inlet Interface M42×1.5,Depth 25mm
Outlet Interface M42×1.5,Depth 25mm


Outline and Installation Dimensions of Complete Equipment Including Motor


complete-install-for-DHP4.5-8.2-high-pressure-pump


Complete Equipment without Independent Fan Motor


Unit: mm

Model A B C D E F G H I J K L IEC Motor
DHP4.5-8.2 417 324 254 15 415 160 969 210 M42 260 204 505 11KW, 4P
417 324 254 15 415 160 1014 254 M42 260 204 550 15KW, 4P
459 368 279 15 455 180 1059 241 M42 260 204 595 18.5KW, 4P
459 368 279 15 455 180 1089 279 M42 260 204 625 22KW, 4P
518
415
318 19
510
200
1165 305
M42 260
204 700
30KW, 4P


Complete Equipment with Independent Fan Motor


Unit: mm

Model A B C D E F G H I J K L IEC Motor
DHP4.5-8.2 417 324 254 15 415 160 969 210 M42 260 204 505 11KW, 4P
417 324 254 15 415 160 1074 254 M42 260 204 610 15KW, 4P
459 368 279 15 455 180 1139 241 M42 260 204 675 18.5KW, 4P
459 368 279 15 455 180 1179 279 M42 260 204 715 22KW, 4P


Installation


Assembly


The figure below shows how the pump is connected to the motor

A: Pump spindle

B: Flexible coupling

C: Bell cover


Note: There should be no axial or radial load on the pump shaft.


Install Note for High Pressure Pump


Reverse Osmosis System Using DHP Series RO High Pressure Pump


① in order to facilitate system flushing and discharge, the ro high pressure pump has integrated a bypass check valve (5) inside the pump.

② Install the inlet filter (1) before the ro high pressure pump (2). Please refer to section 2.8-"Filtering" for instructions on how to select the appropriate filter. Thoroughly clean the pipeline and flush the system before starting.

③ Install a low pressure control switch (3) between the filter and the pump inlet and set 1 Bar (14.5 psi) as the control point. When the pressure is lower than 1 Bar (14.5 psi), the low-pressure switch must be able to shut down the pump.

④ Install a high pressure control switch (7) between the pump outlet and the reverse osmosis membrane inlet, and set 70 Bar (1015 psi) as the control point. When the pressure is higher than 70 Bar (1015 psi), the high-pressure switch must be able to shut down the pump.

⑤ Determine the size of the inlet pipe to minimize the pressure loss (large flow area, short pipe length, as few elbows/joints as possible, and accessories with small pressure loss).

⑥ To eliminate the risk of damage and cavitation, the inlet should always be at positive pressure: minimum 0.5 Bar (7.3psi), maximum 5 Bar (72.5 psi)

⑦ Use elastic hose (4) to minimize vibration and noise.

⑧ Install the safety valve (6) to avoid damage to the system, because the high pressure piston pump will generate pressure and flow immediately after starting without being affected by any reverse pressure.


RO-system-install


Service


The meticulous design makes the DHP series high pressure pump for seawater reverse osmosis have a long running time, low maintenance requirements, and reduce life cycle costs.

If the DHP series ro high pressure pump runs under the specified pre-filtration, pressure and speed conditions, an 8000-hour maintenance-free warranty is provided, but the maximum period from the date of production does not exceed 18 months.


In order to prevent the pump from being completely damaged, it is recommended that you inspect the pump at most 8000 hours, at which time any worn parts must be replaced.


Although the DHP series high pressure pumps for reverse osmosis are made of duplex/super duplex stainless steel with excellent corrosion resistance, it is always recommended to flush the ro high pressure pump with fresh water when the system is shut down.


Maintenance


DHP series ro high pressure pump for seawater reverse osmosis uses water as lubricant, so there is no oil in the pump.

If the ro high pressure pump runs under the curve of SAF 2507 shown in section 2.6, it is not expected that parts need to be replaced during the initial 8000 hours of operation.


China sea water desalination pump


DHP4.5~8.2 vs. APP5.1~10.2 high pressure pump


Product Name DHP Model  Weight [kg] Typical Flow [m3/h] Typical Speed [rpm] Speed Range [rpm] Power Requirement @80 bar Integrated flushing check valve Types of pumps
DHP4.5  AWS180B3005 34.5 4.5 1500 700~1800 15 kW Yes ro high pressure pump
DHP5.3  AWS180B3006 34.5 5.3 1500 700~1800 15 kW Yes ro high pressure pump
DHP6.3  AWS180B3007 34.5 6.3 1500 700~1800 18.5 kW Yes ro high pressure pump
DHP7.2  AWS180B3008 34.5 7.2 1500 700~1800 22 kW Yes ro high pressure pump
DHP8.2 AWS180B3010 34.5 8.2 1500 700~1800 22 kW Yes ro high pressure pump









1. Why do you need to install a filter device before the desalination pump?


In order to extend the service life of the best high pressure water pumps and maintain its pumping stability, please make sure that the medium working condition is consistent with the required working condition. In order to avoid particle wear on the best high pressure water pumps, it is recommended to install an appropriate filter before it.


2. What kind of filter is suitable before the desalination pump?


The main filter must filter 99.98% of particles above 10μm


3. How to avoid cavitation and dry running of the desalination pump?


It is recommended that you install a low-pressure protection switch before the ro high pressure pump inlet. Please refer to the parameter table in the technical specifications of the industrial high pressure water pump for the minimum inlet pressure of different types of pumps; Ensure that the inlet pipe is not smaller than the inlet diameter of the good high pressure water pump.


4. What are the requirements for the frequency converter?


If the good high pressure water pump is used with a frequency converter, the frequency converter is required to be heavy-load constant torque, and the starting mode is constant torque starting. If the special frequency converter for water pump fan is not constant torque, it may not be able to drive the positive displacement water pump; For example, ABB's ACS510 series inverter may not be able to drive the DHP ro high pressure pump. The same is true for other brands of water pump and fan-specific inverters, please pay attention to communicate with the inverter manufacturers for selection.


5. What do we need to pay attention to with this desalination pump?


Please pay attention to the continuous inlet pressure, maximum peak inlet pressure, maximum continuous outlet pressure, and minimum outlet pressure operating ranges of different types of high pressure pumps. For details, please refer to the parameter table in the ro high pressure pump technical specification. Ensure that the pressure when the industrial high pressure water pump is running does not exceed the range required by the specification.


6. What are the precautions for startup commissioning of the desalination pump?


Before starting the ro high pressure pump, it is recommended that you thoroughly flush the pipeline and system to remove any residues or foreign objects that may be present. It is strongly recommended that you drain the air from the pump and system.


Test whether the direction of the ro high pressure pump is consistent with the arrow mark on the pump. “I” represent the inlet of the high-pressure water pump, and “O” represents the outlet of the industrial high pressure water pump.


7. How to maintain the desalination pump?


For a short shutdown of the small high pressure water pump within 3 days, there is no need to flush while keeping the pump full of overflow medium.

If the small high pressure water pump has been shut down for more than 3 days, it is recommended that you flush the pump with fresh water. When the small high pressure water pump has been shut down for more than 15 days, it is recommended that you flush the pump with fresh water containing fungicides.

If the small high pressure water pump is running under conditions of high salt content, it is recommended that you flush the pump with fresh water every time you stop.


8. How should the pump run under conditions of high salt content?


If the pump is running under conditions of high salt content, it is recommended that you flush the pump with fresh water every time you stop it.


9. What to do if the pump has abnormal noise and vibration during operation?


If abnormal noise and vibration occur during the operation of the ro high pressure pump, please stop the high pressure piston pump immediately and perform maintenance on it.


10. What to pay attention to when the back-end valve is closed?


It is forbidden to start the high pressure piston pump when the rear valve is closed, otherwise it will cause the safety valve to work, or even the pipeline burst.


11. How to connect high pressure hose


It is recommended that the ro high pressure pump outlet adopt a flexible connection method of high-pressure hose.


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