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DHP11-15 High Pressure Pump

The DHP11, DHP13.5, DHP15 series high-pressure pumps are designed to transport high-pressure, low-viscosity corrosive fluids, such as high-pressure brine (seawater) in seawater reverse osmosis.

Based on the principle of axial piston pumps, the DHP11, DHP13.5, DHP15 series pumps 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 pumps is integrated with a check valve, which allows fluid to flow from the inlet to the outlet via the check valve when the pump stops.

The DHP11, DHP13.5, DHP15 series pumps are fixed displacement pumps, and the flow rate is proportional to the speed of the input shaft and the displacement of the pump.
 

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Overview


The DHP11, DHP13.5, DHP15 series high-pressure pumps are positive displacement pumps with nine axial pistons that move a fixed amount of water in each cycle. The 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 DHP11, DHP13.5, DHP15 range of high-pressure 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 DHP11, DHP13.5, DHP15 series high-pressure 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


√ 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


Specification DHP11 DHP13.5 DHP15
Geometric displacement cm3/rpm 133 163 181
Rated flow at 1500rpm, m3/h 11 13.5 15
Minimum outlet pressure, Bar 10 10 10
Maximum continuous outlet pressure, Bar 80 80 80
Maximum gap outlet pressure, Bar 100 100 100
Minimum inlet pressure, Bar 2 2 2
Maximum continuous inlet pressure, Bar 5 5 5
Maximum continuous speed, rpm 1500 1500 1500
Minimum continuous speed, rpm 700 700 700
Noise dB(A) ≤85 ≤85 ≤85
Power when rated speed 1500rpm and outlet   pressure 80Bar, kW 30 37 45
Weight, kg 52 52 52
Integrated flushing check valve 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-DHP11-15-HP-PUMP


Not only that, the graph also shows that the flow rate can vary with the speed of the pump. 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
DHP11 183 11 22kW 30kW 30kW 1500
DHP13.5 224 13.5 30kW 37kW 37kW 1500
DHP15 250 15 37kW 37kW 45kW 1500


Inlet pressure


The DHP series high-pressure pump can directly supply water from the feed water pump, and the pressure of the water inlet of the 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


High-pressure pump 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 pumps are made of 2507.


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


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


High-pressure pump storage


Storage temperature: -40°C to +70°C (the 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 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 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-pump-11-15


PUMP MODEL DHP11~DHP15
Flat key (mm) 12×8×40
Exhaust Plug 8mm inner hexagon
Inlet Interface M52×1.5,Depth 17mm
Outlet Interface M52×1.5,Depth 17mm


Outline and Installation Dimensions of Complete Equipment Including Motor


complete-install-for-DHP11-17.5-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
DHP11-15 459 368 279 15 455 180 1104 279 M52 275 204 625 22KW, 4P
518 415 318 19 510 200 1179 305 M52 275 204 700 30KW, 4P
542 443 356 19 545 225 1189 286 M52 275 234 680 37KW, 4P
542 443 356 19 545 225 1244 311 M52 275 234 735 45KW, 4P
603 485 406 24 610 250 1320 349 M52 275 275 770 55KW, 4P


Complete Equipment with Independent Fan Motor


Unit: mm

Model A B C D E F G H I J K L IEC Motor
DHP11-17.5 459 368 279 15 455 180 1194 279 M50 275 204 715 22KW,   4P
518 415 318 19 510 200 1249 305 M50 275 204 770 30KW,   4P
542 443 356 19 545 225 1249 286 M50 275 234 740 37KW,   4P
542 443 356 19 545 225 1304 311 M50 275 234 795 45KW,   4P
603 485 406 24 610 250 1430 349 M50 275 275 880 55KW,   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 High Pressure Pump


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

② Install the inlet filter (1) before the 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 plunger 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 pumps have a long running time, low maintenance requirements, and reduce life cycle costs.

If the DHP series 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 are made of duplex/super duplex stainless steel with excellent corrosion resistance, it is always recommended to flush the pump with fresh water when the system is shut down.


Maintenance


DHP series high pressure pump uses water as lubricant, so there is no oil in the pump.

If the 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.






1. Why do you need to install a filter device before the high pressure water pump?


In order to extend the service life of the high-pressure water pump 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 high-pressure water pump, it is recommended to install an appropriate filter before it.


2. What kind of filter is suitable before the high-pressure water pump?


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


3. How to avoid cavitation and dry running of high-pressure water pump?


It is recommended that you install a low-pressure protection switch before the high-pressure pump inlet. Please refer to the parameter table in the technical specifications of the 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 high-pressure water pump.


4. What are the requirements for the frequency converter?


If the 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 high pressure water 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 high-pressure water 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 water pumps. For details, please refer to the parameter table in the high-pressure pump technical specification. Ensure that the pressure when the 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 high-pressure water pump?


Before starting the 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 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 high-pressure water pump.


7. How to maintain the high-pressure water pump?


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

If the 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 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 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 pump, please stop the HP 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 HP 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 pump outlet adopt a flexible connection method of high-pressure hose.


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