DHP 15 Axial Piston Pumps(High Pressure Pump For Industrial Reverse Osmosis)

The DHP 15 Axial Piston Pump is a High Pressure Pump For Industrial Reverse Osmosis developed by Wuxi Fenigal Science and Technology Co., Ltd. in collaboration with its OEM partner, Shenzhen CW Environment Technology. Specifically designed for conveying high-pressure, low-viscosity corrosive fluids in industrial reverse osmosis systems, it serves as a core piece of equipment to meet the high-pressure fluid transfer needs in scenarios such as seawater desalination and industrial wastewater zero-liquid discharge.

As one of the technological achievements of Fenigal after over 30 years of dedication to high-pressure plunger pumps, the DHP 15 is developed based on the axial piston pump principle. It realizes fluid transfer through the reciprocating motion of plungers parallel to the drive shaft within plunger bores, which creates volume changes. Its core advantage lies in the adoption of "fluid self-lubrication" technology—using the conveyed liquid as the lubricating medium, it completely eliminates the lubricating oil tank of traditional plunger pumps, fundamentally preventing oil leakage from contaminating reverse osmosis media. This makes it particularly suitable for scenarios with strict requirements on medium purity, such as seawater desalination and pharmaceutical raw material liquid concentration. Meanwhile, the pump is integrated with a check valve structure, which ensures one-way fluid flow from the inlet to the outlet when the pump is stopped, preventing medium backflow from damaging pump body seals and reverse osmosis membrane elements, thus guaranteeing system safety and stability.

In terms of materials and performance, the DHP 15 inherits the core characteristics of the DHP series: "corrosion resistance, high efficiency, and low noise". Key components are made of 2205 duplex stainless steel (SAF 2205 / EN 1.4462 / UNS 31803), providing excellent corrosion resistance against high-salt media and enabling long-term resistance to corrosive fluids such as seawater and high-concentration industrial wastewater. During operation, its pulsation amplitude is much smaller than that of centrifugal pumps, and the optimized design of multiple plungers further reduces vibration and noise (≤85 dB(A)), making it suitable for food and pharmaceutical workshops with high requirements for the operating environment. Its compact structure allows direct installation on motors or internal combustion engines without occupying additional large space, making it applicable to space-constrained scenarios such as islands and coastal factories.

In terms of application scenarios, as a High Pressure Pump For Industrial Reverse Osmosis, the DHP 15 is widely used in three core fields: (1) Seawater and brackish water desalination systems in islands and coastal areas, providing support for domestic water supply for residents and industrial production water supply; (2) Industrial wastewater zero-liquid discharge treatment, such as desalination and salt concentration of desulfurization wastewater from coal-fired power plants and coking wastewater from coal mines, realizing the recycling of water resources; (3) Membrane concentration processes for raw material liquids in the food and pharmaceutical industries, such as juice concentration and purification of traditional Chinese medicine extracts, meeting high hygiene standards. This is highly consistent with Fenigal's positioning since it became the first domestic enterprise to develop axial high-pressure plunger pumps in 1990: "promoting localization and breaking technical bottlenecks". Its technical level and product quality have reached the world's advanced level, enabling stable adaptation to various industrial reverse osmosis systems.

Core Technical Parameters

The technical parameters of the DHP 15 high-pressure plunger pump cover key indicators such as geometric displacement, flow rate, pressure, rotation speed, power, and temperature adaptability, which are the core basis for system selection and equipment matching. The specific parameters are shown in the table below:

Flow Characteristics at Different Rotation Speeds

As a fixed-displacement axial piston pump, the flow rate of the DHP 15 has a strictly proportional relationship with the input shaft rotation speed (the flow rate/rotation speed ratio is fixed). The flow rate required by the system can be flexibly matched by adjusting the motor rotation speed. If the actual flow rate required by the system is known, the corresponding motor rotation speed can be calculated using the following formula:
Selected Motor Rotation Speed (r/min) = (Required Flow Rate (m³/h) × Rated Rotation Speed (1500 r/min)) / Rated Flow Rate (15 m³/h)

The figure below shows the flow rate-rotation speed curve of the DHP 15 at 80 Bar pressure, which allows for an intuitive view of the actual flow rate corresponding to different rotation speeds (e.g., approximately 7 m³/h at 700 rpm and the rated 15 m³/h at 1500 rpm), providing a visual reference for system rotation speed matching and flow rate adjustment:

Installation and Operation Specifications

As a High Pressure Pump For Industrial Reverse Osmosis, the DHP 15 must be installed and operated in strict accordance with specifications to ensure stable system operation and extend the pump's service life. The core points are as follows:

1. Filtration Requirements: Since reverse osmosis media (such as seawater and high-salt wastewater) may contain tiny particles, a depth filter with an accuracy of 10 μm (absolute accuracy) must be installed at the inlet of the DHP 15. It is required to have a filtration efficiency of 99.98% for particles larger than 10 μm (β10>5000). This is because the precision clearance between the plunger and plunger sleeve inside the pump is designed to be extremely small (to control internal leakage and improve efficiency); if particles enter, they will cause rapid wear of components and even lead to pump body failure. The use of bag filters with only 90% efficiency is prohibited; spiral-wound filter elements are recommended.

2. Pressure Control: A low-pressure control switch (set to 1 Bar) must be installed at the inlet to automatically shut down the pump when the pressure is lower than 1 Bar, preventing cavitation from damaging the plunger. A high-pressure control switch (set to 70 Bar) must be installed between the outlet and the reverse osmosis membrane to shut down the pump when the pressure exceeds the limit. At the same time, a safety valve (refer to the specifications in Chapter 10 of the document) must be installed to avoid damage to the membrane element due to instantaneous pressure after the pump starts.

3. Pre-Startup Preparation: Before startup, thoroughly flush the pipelines and system to remove welding slag and debris; discharge the air from the pump and system through the pump body exhaust valve to prevent cavitation; confirm that the pump rotation direction is consistent with the arrow on the pump body. Starting the pump with the outlet valve closed is prohibited (as it may cause frequent operation of the safety valve or pipeline burst).

The figure below shows the standard connection method between the DHP series high-pressure pump and the motor. When installing the DHP 15, ensure that the coupling clearance is at least 3-5 mm and that there is no axial/radial load on the pump shaft to avoid bearing wear or seal leakage caused by misalignment:

Detailed Power Parameters

The power consumption of the DHP 15 changes with the operating pressure. The power values at different typical pressures are shown in the table below, which can be directly used for system motor selection (e.g., matching a 45 kW motor can meet the rated operation requirements at 80 Bar and avoid motor overload):

Outline and Installation Dimensions

The outline dimensions of the DHP 15 (especially the inlet and outlet interface dimensions) and the installation dimensions of the complete equipment (including the frequency conversion motor) are the key basis for pipeline connection, on-site layout, and foundation design. The details are as follows:

1. Interface Dimensions: Both the inlet and outlet of the DHP 15 feature M52×1.5 threads with a depth of 17 mm. High-pressure pipe fittings of the corresponding specifications (refer to the "High-Pressure Hose Connector" specifications in Chapter 11 of the document) must be matched to ensure the sealing performance of the interface and prevent high-pressure fluid leakage.

2. Complete Equipment Dimensions: When the DHP 15 is equipped with an independent fan motor (frequency conversion motor), the installation dimensions corresponding to motors of different powers are shown in the table below (Unit: mm), which can be used for on-site space planning and equipment fixing design:

The figure below is the outline structure diagram of the DHP 15, marking the positions of key components such as the inlet, outlet, installation interface, and exhaust valve, which facilitates on-site installation positioning and pipeline connection:

High-Pressure Piston Pump Maintenance and Warranty Services

Maintenance Recommendations

Although the DHP 15 adopts a self-lubricating design (no lubricating oil required), proper maintenance can significantly extend its service life (designed for over 8000 hours of operation). The core maintenance points are as follows:

• Daily Maintenance: During operation, real-time monitoring of noise and vibration is required. If abnormalities occur (such as a sudden increase in noise or intensified vibration), the pump must be shut down immediately for inspection to check for plunger wear, seal aging, or insufficient inlet pressure. In high-salt environments (such as seawater desalination), the pump cavity must be flushed with fresh water after each shutdown to discharge concentrated brine and prevent salt crystallization from damaging the plunger and seals—during flushing, the pump can be started briefly to ensure complete discharge of residual brine in the pump cavity.

• Shutdown Maintenance: For short-term shutdowns (≤3 days), no flushing is required; the pump only needs to be kept filled with the medium. For medium-term shutdowns (3～15 days), thorough flushing with fresh water is necessary. For long-term shutdowns (>15 days), flushing with fresh water containing a bactericide is required to prevent microbial growth from causing component corrosion. After flushing, the pump inlet and outlet must be sealed to prevent impurities from entering.

• Regular Inspection: A comprehensive disassembly and inspection is recommended after 8000 hours of operation. Worn parts (such as seal plates, plunger sleeves, and springs) should be replaced, and the tightness of the check valve should be checked to ensure no internal leakage. The wear of the inlet and outlet interface threads should also be inspected, and the sealing gasket should be replaced in a timely manner to avoid high-pressure leakage.

Warranty Service Details

Fenigal provides comprehensive warranty and maintenance services for the DHP 15, covering the full-life-cycle usage needs of the equipment. The specific details are shown in the table below:

For maintenance or warranty inquiries, please contact Wuxi Fenigal Science and Technology:

• Address: Chuangyi Chanye Park, No. 100 Dicui Road, Binhu District, Wuxi City, Jiangsu Province, China

• Tel: +86-510-85163211

• Email: [email protected]

• Official Website: https://www.fgwater.com

• PDF manual download address:DHP type plunger pump selection manual.pdf