DHP 13.5 Axial Piston Pumps(High Pressure Pump For Industrial Reverse Osmosis)

The DHP 13.5 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. It is specifically designed for conveying high-pressure, low-viscosity corrosive fluids in industrial reverse osmosis systems, such as seawater/brackish water desalination, industrial wastewater zero-liquid discharge salt concentration, and landfill leachate treatment.

Based on the axial piston pump principle, this pump operates by the reciprocating motion of plungers parallel to the drive shaft within plunger bores, which creates volume changes to achieve fluid transfer. 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 avoiding oil leakage pollution. This makes it particularly suitable for reverse osmosis systems with high requirements for medium purity. Meanwhile, the DHP 13.5 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 the pump body and reverse osmosis membrane, thus ensuring system safety.

As an important model in the DHP series, the DHP 13.5 inherits the core characteristics of the series: "corrosion resistance, high efficiency, and low noise". Its key components are made of 2205 duplex stainless steel (SAF 2205 / EN 1.4462 / UNS 31803), providing excellent corrosion resistance against high-salt media. During operation, its pulsation is much smaller than that of centrifugal pumps and other pump types, and the optimized design of the number of plungers further reduces the pulsation amplitude, achieving low vibration and low noise (≤85 dB(A)). Its compact structure allows it to be directly installed on motors or internal combustion engines, making it suitable for industrial sites sensitive to installation space.

In terms of application scenarios, as a High Pressure Pump For Industrial Reverse Osmosis, the DHP 13.5 is widely used in three core fields: 

(1) Seawater and brackish water desalination systems in islands and coastal areas; 

(2) Desalination and resource recovery of industrial wastewater such as desulfurization wastewater from coal-fired power plants and coking wastewater from coal mines; 

(3) Membrane concentration processes for raw material liquids in the food and pharmaceutical industries (meeting the demand for low-viscosity medium conveyance).

 This is highly consistent with Fenigal's positioning since it started developing high-pressure plunger pumps in 1990: "promoting the localization of axial high-pressure plunger pumps and breaking foreign technological monopolies". Its technical level and product quality have reached the world's advanced level, which can meet the stable demand for high-pressure fluid conveyance in industrial reverse osmosis systems.

Core Technical Parameters

The technical parameters of the DHP 13.5 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 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 13.5 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 (13.5 m³/h)

The figure below shows the flow rate-rotation speed curve of the DHP 13.5 at 80 Bar pressure, which allows for an intuitive view of the actual flow rate corresponding to different rotation speeds (e.g., the flow rate is approximately 6 m³/h at 700 rpm, and reaches the rated 13.5 m³/h at 1500 rpm), providing a visual reference for system rotation speed matching:

Installation and Operation Specifications

As a High Pressure Pump For Industrial Reverse Osmosis, the DHP 13.5 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 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 13.5. It is required to have a filtration efficiency of 99.98% for particles larger than 10 μm (β10>5000)—this is because the precision clearances (such as between the plunger and plunger sleeve) inside the pump are designed to be extremely small, and the entry of particles will cause severe wear. 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. 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 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 13.5, 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 damage caused by misalignment:

Detailed Power Parameters

The power consumption of the DHP 13.5 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 37 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 13.5 (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 and on-site layout. The details are as follows:

1. Interface Dimensions: Both the inlet and outlet of the DHP 13.5 are M52×1.5 threads with a depth of 17 mm, and 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 avoid interface leakage.

2. Complete Equipment Dimensions: When the DHP 13.5 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 foundation design and space planning:

The figure below is the outline structure diagram of the DHP 13.5, marking the positions of key components such as the inlet, outlet, installation interface, and exhaust valve, which facilitates on-site installation and positioning:

High-Pressure Piston Pump Maintenance and Warranty Services

Maintenance Recommendations

Although the DHP 13.5 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, and other issues. 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 plungers and seals.

• Shutdown Maintenance: For short-term shutdowns (≤3 days), no flushing is required, and 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.

• Regular Inspection: A comprehensive disassembly and inspection is recommended after 8000 hours of operation, and worn parts (such as seal plates, plunger sleeves, and springs) should be replaced to avoid overall failures caused by local wear.

Warranty Service Details

Fenigal provides comprehensive warranty and maintenance services for the DHP 13.5, as shown in the table below, to meet the customer's full-life-cycle usage needs:

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

• Address: Chuangyi Industry 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