Double Pilot Check Valve
YUNLINK double pilot check valves use two cross-piloted check elements to block reverse flow in both actuator lines until pilot pressure opens the opposite side. The range includes threaded, flange-mounted and plate-type configurations, with model-specific flow capacity, working pressure, pilot ratio and port options.
Description:
YUNLINK double pilot check valves are used in hydraulic cylinder circuits where load holding is required in both directions. Two cross-piloted check elements allow flow toward the cylinder ports while blocking reverse flow until pilot pressure from the opposite line opens the corresponding check valve.
The range includes VRDE threaded models, VRDE F FF-G and VBPDE A configurations, VRDL-FL flange-mounted models, and the SO-K8L-41B plate-type model. Depending on the model, maximum flow ranges from 20 to 120 L/min, maximum pressure is up to 350 bar, and pilot ratio, port size and mounting dimensions vary by series. Select the valve according to required flow, pressure, pilot ratio, port size and mounting type.
Key Specifications
- Product Type: Double pilot-operated check valve
- Available Configurations: Threaded, flange-mounted and plate-type
- Maximum Working Pressure: Up to 350 bar, depending on model and body material
- Maximum Flow: 20 to 120 L/min, depending on model
- Pilot Ratio: 4:1 to 7.1:1, depending on series
- Cracking Pressure: 3.5 bar on specified VRDE and VRDL-FL models
- Port Options: BSPP G1/4 to G3/4; M14×1.5 on SO-K8L-41B
- Selection Parameters: Flow, pressure, pilot ratio, port size and mounting type
Series & Mounting Configurations
VRDE Threaded Series
BSPP threaded models are available from G1/4 to G3/4, with maximum flow from 20 to 80 L/min and maximum working pressure up to 350 bar.
VRDE F FF-G Series
Models range from VRDE 01 F FF to VRDE 04 F FF, with G1/4 to G3/4 port options and maximum flow from 30 to 120 L/min.
VRDL-FL Flange-Mounted Series
Flange-mounted models are available from G1/4 to G3/4. Maximum flow ranges from 20 to 100 L/min. Steel versions are rated up to 350 bar and aluminium versions up to 210 bar.
VBPDE A & Plate-Type Models
VBPDE A models are available in G3/8 and G1/2 sizes. The SO-K8L-41B provides a plate-type configuration with M14×1.5 ports and maximum flow of 40 L/min.
Connection Standards & Port Options
VRDE BSPP Ports
Standard VRDE threaded models use BSPP connections from G1/4 to G3/4. Available sizes include G1/4, G3/8, G1/2 and G3/4.
VRDE F FF-G Ports
VRDE F FF-G models are available with G1/4, G3/8, G1/2 and G3/4 ports. Port size changes according to the selected model code.
VRDL-FL & VBPDE A Ports
VRDL-FL flange-mounted models are available from G1/4 to G3/4. VBPDE A block models are available with G3/8 or G1/2 ports.
SO-K8L-41B Plate Ports
The SO-K8L-41B plate-type model uses M14×1.5 connections at the V1 and V2 ports. Confirm the mounting dimensions before replacement or installation.
Flow, Pressure & Pilot Ratio Selection
VRDE Flow & Pressure
Standard VRDE models are available with maximum flow ratings of 20, 50 or 80 L/min. VRDE F FF-G models extend the available range from 30 to 120 L/min. Maximum working pressure is 350 bar.
VRDL-FL Material Ratings
VRDL-FL models cover maximum flow ratings from 20 to 100 L/min. Steel versions are rated up to 350 bar, while aluminium versions are rated up to 210 bar.
VBPDE A & Plate-Type Ratings
VBPDE A models are rated at 30 or 55 L/min with maximum pressure of 350 bar. SO-K8L-41B is rated at 40 L/min and 350 bar.
Model-Specific Pilot Ratios
Pilot ratios range from 4:1 to 7.1:1 depending on the series and model size. Confirm the required pilot ratio together with flow, working pressure and actuator conditions.
Cracking Pressure & Operating Conditions
Specified Cracking Pressure
Standard VRDE and VRDL-FL models listed in the datasheet have a cracking pressure of 3.5 bar. Confirm this value against the selected model before ordering.
VRDE Temperature Range
For the standard VRDE series, the recommended operating temperature is +40°C to +70°C, with a maximum operating temperature of +90°C. The stated ambient range is -20°C to +60°C.
VRDE Materials & Seals
The standard VRDE series is specified with a steel body, hardened-steel valve components and NBR seals.
Model-Specific Verification
Cracking pressure, material and temperature data are not listed uniformly for every series. Confirm these conditions for the exact model, body material and application.
Hydraulic Function & Circuit Operation
Free flow: Flow from V1 to C1 and from V2 to C2 passes through the check elements toward the actuator.
Load holding: Reverse flow from C1 or C2 remains blocked when pilot pressure is not applied.
Cross-pilot release: Pressure in one valve line pilots open the check element on the opposite side, allowing return flow from the corresponding actuator port.
How to Specify a Double Pilot Check Valve
1. Required Flow
Specify the maximum flow required by the hydraulic circuit.
2. Working Pressure
Confirm the maximum system and load pressure for the application.
3. Pilot Ratio
Select the pilot ratio according to circuit pressure, load conditions and required release pressure.
4. Port Size & Thread
Confirm the required BSPP port size or M14×1.5 plate connection.
5. Mounting Configuration
Choose a threaded, flange-mounted, block or plate-type configuration.
6. Model & Application Details
Provide the existing valve model, mounting dimensions, hydraulic schematic or equipment application when requesting a replacement.
Applications
Mobile Machinery Hydraulic Systems
Industrial Hydraulic Systems
Bidirectional Cylinder Locking Circuits
Need Help Selecting a Double Pilot Check Valve?
Send us the existing valve model, hydraulic schematic, required flow, working pressure, pilot ratio, port size, mounting type or key dimensions. Our team can review the information and help match a suitable double pilot check valve configuration for quotation.
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