Product Overview
The CPOM Series sandwich pilot-operated check valves — covering models CPOM2DDV50, CPOM2DDV56, CPOM2DDV57, CPOM2DDV60, and CPOM3DDV50 — are core products within the Parker Hannifin Manapak family. These pilot-operated check valves feature a sandwich (modular) mounting design, allowing direct stacking beneath directional valves with standardized mounting interfaces, greatly simplifying the configuration of hydraulic stack systems.
The series offers 1-way bi-directional check valve functionality, with poppet-type check elements at both ports “A” and “B”. The core function is: when the directional valve is in the center position, the valve locks the actuator ports to ensure leak-free positioning of the actuator; when the directional valve shifts, pilot pressure simultaneously opens the opposite check valve to enable return flow.
As a high-performance alternative to genuine Parker CPOM series products, this valve delivers full performance parity with Parker original specifications, featuring 100% form-fit-function interchangeability — mounting interfaces and dimensions are identical to the original, enabling direct replacement without manifold modifications. Every unit undergoes 100% simulated in-service testing prior to shipment, ensuring proven reliability under real-world operating conditions.
Technical Specifications
Brand: Parker Hannifin
Series: CPOM Series Pilot-Operated Check Valve
Models: CPOM2DDV50 / CPOM2DDV56 / CPOM2DDV57 / CPOM2DDV60 / CPOM3DDV50
Size Equivalents: CPOM2 – NG6 (CETOP 3 / NFPA D03); CPOM3 – NG10 (CETOP 5 / NFPA D05)
Mounting Interface Standard: ISO 4401 / NFPA / CETOP
Maximum Operating Pressure: 350 bar (5000 PSI)
Cracking Pressure: CPOM2 – 1.0 bar; CPOM3 – 0.8 bar
Pilot Ratio: 3:1 (standard); Optional 7:1 / 6.5:1
Nominal Flow: CPOM2 – up to 114 L/min (30 GPM); CPOM3 – up to 114 L/min (30 GPM)
Maximum Flow: CPOM3DDV – up to 100 L/min
Rated Flow (CPOM3DDV): 74 L/min
Body Material: Steel
Seal Material: FKM (Fluorocarbon); Optional NBR (Buna-N)
Hydraulic Fluid: Mineral oil (per DIN 51524)
Fluid Temperature Range: -20℃ to +80℃
Ambient Temperature Range: -20℃ to +50℃
Recommended Fluid Cleanliness: ISO 4406 Class 18/16/13 (equivalent to NAS 1638 Class 7)
Weight: CPOM2 – 1.8 kg; CPOM3 – 4.0 kg
Mounting Orientation: Unrestricted
Key Technical Advantages
1. Sandwich (Modular) Design for Efficient System Integration
The CPOM series features a sandwich mounting design, allowing the valve body to be stacked directly beneath standard directional valves. This eliminates the need for additional piping, greatly simplifying hydraulic manifold layout and assembly, saving installation space, and reducing system leakage risk. The modular design enables extremely flexible configuration of stack systems based on functional requirements.
2. Steel Body with Precision-Guided Poppet for Superior Sealing
The valve body is manufactured from steel for high strength and excellent pressure resistance. The poppet is precisely guided within a steel sleeve, ensuring proper alignment and sealing against the seat. The metal-to-metal poppet sealing configuration delivers zero-leakage locking even under high pressure, ensuring reliable actuator positioning at any position.
3. Large Cross-Section Flow Path for High Flow at Low Differential Pressure
When the poppet is open, the large cross-section flow path allows high flow rates with minimal pressure drop. This characteristic is particularly critical in high-speed actuator circuits — delivering locking functionality without sacrificing system speed and response performance.
4. Independent Bi-Directional Control with Flexible A/B Port Configuration
The CPOM series features independent poppet-type check elements at both ports A and B. Based on functional requirements, options are available for controlling only port A, only port B, or both A and B simultaneously. When the directional valve shifts, pilot pressure simultaneously opens the opposite check valve, enabling smooth bi-directional flow switching.
5. Multiple Pilot Ratio Options for Diverse System Pressures
Standard configuration offers a 3:1 pilot ratio. The CPOM2 and CPOM3 series also offer optional high-ratio versions at 7:1 or 6.5:1 to accommodate different system pressure requirements and opening reliability needs, providing engineers with greater selection flexibility.
Application Areas
Leak-Free Actuator Positioning: Stacked with directional control valves to lock hydraulic cylinders or motors in any position when the directional valve is in neutral
Hydraulic Stack System Integration: As a core component of modular valve stacks, combined with other sandwich valves (pressure reducing, throttle, relief valves) on integrated manifolds
Injection Molding & Die-Casting Hydraulic Systems: Position holding and speed control for clamping cylinders and ejector cylinders
Construction Equipment Hydraulic Systems: Circuit locking and safety protection for working attachments on excavators, loaders, and similar equipment
Machine Tool Hydraulic Systems: Position holding and fall prevention for feed cylinders and clamping cylinders
Industrial Hydraulic Power Units (HPU): Standard functional modules in hydraulic circuits
Expert Maintenance Tips
Mounting Surface Cleaning & Inspection: Thoroughly clean the manifold and sandwich mounting surfaces prior to installation to remove oil residue, chips, and contaminants. Inspect all O-ring seal grooves on the mounting surface for damage or burrs, and repair as necessary.
O-Ring Replacement: Replace all O-ring seals on the sandwich mounting surfaces after every disassembly. The CPOM series is standard-equipped with FKM (Fluorocarbon) seals, suitable for mineral oils and a wide temperature range. For special media compatibility (e.g., phosphate ester fluids), select appropriately formulated seal materials.
Torque Control: Tighten mounting bolts in a diagonal sequence using a torque wrench in gradual increments. Avoid over-tightening on one side, which may cause valve body distortion or seal failure. Refer to the Parker CPOM series product installation manual for specific torque values.
Fluid Cleanliness Management: The CPOM series is sensitive to fluid cleanliness. Maintain system fluid cleanliness at ISO 4406 Class 18/16/13 or higher (equivalent to NAS 1638 Class 7 or better). Install a filter with ≤10μm rating in the return line where feasible.
Pilot Pressure Verification: Ensure that pilot control pressure is sufficient to reliably open the check valve. Based on the 3:1 pilot ratio, pilot pressure should be at least 1/3 of the locked port pressure (theoretical minimum). In practice, a safety margin of no less than 20% above the theoretical minimum is recommended.
Periodic Functional Testing: Test the check valve locking and release functions every 2,000 operating hours or annually. If the actuator fails to hold position reliably (creeping, drifting) or exhibits abnormal shifting behavior, disassemble and inspect the poppet and seat for wear — replace the valve cartridge assembly if necessary.
