The LDJ-M hydraulic diaphragm metering pump is a precision chemical dosing solution developed for high-pressure, large-flow and demanding industrial processes. The pump uses a hydraulically actuated diaphragm to isolate the process liquid from the transmission components, providing reliable sealing and reducing the risk of chemical leakage.



With a maximum single-head capacity of up to 40,000 L/h, discharge pressure up to 50 MPa and steady-state metering accuracy of ±1%, the LDJ-M series can meet a wide range of chemical injection and liquid delivery requirements. It is suitable for handling corrosive, hazardous, toxic, high-temperature and valuable process fluids.



An automatic hydraulic oil compensation system helps maintain stable diaphragm movement and consistent dosing performance. The built-in combined safety valve protects the pump against excessive pressure while automatically releasing trapped gas from the hydraulic chamber. Optional double-diaphragm leakage detection can provide local or remote alarms for safety-critical applications.



The LDJ-M series is available with stainless steel, PVC and other customized liquid-end materials. Different pump-head structures, check valves, diaphragm materials, connection standards and control methods can be selected according to the pumped medium and operating conditions.



LDJ-M hydraulic diaphragm metering pump advantages:
1. Accurate Chemical Metering
The hydraulic diaphragm transmission provides repeatable displacement during every operating cycle, helping maintain stable chemical concentration and process control.
2. Completely Sealed Pump Head
The process liquid is isolated from the plunger, gearbox and hydraulic transmission components. This structure minimizes leakage and is especially useful for toxic, corrosive or valuable chemicals.
3. Reliable High-Pressure Performance
The LDJ-M series is designed for chemical injection systems requiring both high discharge pressure and dependable continuous operation.
4. Automatic Hydraulic Oil Control
The automatic oil compensation system maintains the proper hydraulic oil volume and reduces the possibility of diaphragm deformation or unstable delivery.
5. Integrated Overpressure Protection
A built-in combined safety valve helps protect the diaphragm, hydraulic chamber and associated piping when the discharge pressure exceeds the permitted operating range.
6. Flexible Liquid-End Configurations
Pump heads, diaphragms, plungers, check valves, packing materials and pipe connections can be selected according to chemical compatibility and process conditions.
7. Enhanced Safety Options
For hazardous applications, an optional double-diaphragm system can detect diaphragm damage and activate a local or remote alarm before the process liquid reaches the hydraulic end.

The LDJ-M hydraulic diaphragm metering pump is suitable for the following industries and processes:
1. Petroleum and Petrochemical Industry
Used for injecting corrosion inhibitors, scale inhibitors, demulsifiers, catalysts, additives and other chemicals into pipelines and processing systems.
2. Oil and Gas Chemical Injection Skids
Suitable for land-based and offshore oil and gas skid-mounted chemical injection packages requiring accurate and dependable dosing.
3. Chemical Processing
Applied in the metering and delivery of acids, alkalis, solvents, additives, catalysts and other corrosive or hazardous liquids.
4. Industrial Water Treatment
Used for dosing coagulants, flocculants, disinfectants, pH-regulating chemicals, corrosion inhibitors and scale-control chemicals.



5. Power and Nuclear Power Plants
Suitable for boiler-water treatment, cooling-water treatment, condensate treatment and other critical chemical dosing processes.
6. Offshore Engineering
The sealed diaphragm construction and optional leakage alarm make the pump suitable for offshore platforms and marine chemical injection systems.
7. Pharmaceutical Processing
Used for controlled dosing of chemical ingredients and process liquids where accurate delivery and leakage prevention are important.



8. Pulp and Paper Industry
Suitable for injecting bleaching agents, dyes, process additives, retention chemicals and water-treatment chemicals.
9. Food Processing
Can be configured for controlled delivery of food-processing additives and cleaning chemicals when suitable liquid-end materials are selected.
10. Environmental Protection
Used in wastewater treatment, chemical neutralization, sludge conditioning and industrial pollution-control systems.
11. Military and Special Industrial Processes
Suitable for specialized processes requiring accurate metering, high pressure, reliable sealing and customized materials.

1. Hydraulically actuated diaphragm for stable and accurate dosing
2. Maximum single-head flow rate up to 40,000 L/h
3. Maximum discharge pressure up to 50 MPa
4. Steady-state metering accuracy of ±1%
5. Suitable for liquids with viscosity from 0 to 800 mm²/s
6. Fully sealed pump head for leak-free operation
7. PTFE diaphragm provides chemical resistance and reliable sealing
8. Automatic hydraulic oil compensation system
9. Hydraulic oil degassing design maintains oil rigidity
10. Built-in combined safety valve prevents excessive pressure
11. Automatic venting of trapped gas in the hydraulic chamber
12. Full rear-position diaphragm control system
13. Stainless steel, PVC and customized liquid ends available
14. Single-head and multi-head configurations available
15. Optional metal diaphragm pump head
16. Optional insulation or heating jacket
17. Optional double-diaphragm leakage detection
18. Local or remote diaphragm rupture alarm available
19. Pressure-type or electrolyte-type detection options
20. Single-ball, double-ball and cone-type check valves available
21. Customized pump-head, valve, plunger and sealing materials
22. Suitable for continuous industrial chemical injection
23. Designed and manufactured according to GB/T 7782-2008