CRG Series Right Angle Check Valves

Overview

The CRG Series is a pilot-operated check valve family designed for high-performance load holding and controlled release in hydraulic systems. Available in three standard sizes—CRG-03, CRG-06 and CRG-10 —these valves provide reliable, leak-free blocking of reverse flow while allowing free flow in the forward direction. The CRG series combines robust construction with precise hydraulic pilot control, making it ideal for safety-critical applications requiring secure load retention and smooth, controlled release.

Key Features

Primary Functions

1. Secure Load Holding — Blocks reverse flow to maintain cylinder or motor position under load without drift

2. Controlled Release — Hydraulic pilot signal opens valve to permit controlled reverse flow for load lowering

3. System Isolation — Electrically isolates hydraulic circuits for maintenance or emergency stop functions

4. Safety Protection — Prevents uncontrolled load descent due to hose failure, pipe rupture, or power loss

5. Energy Efficiency — Allows pump unloading while maintaining load position, reducing heat generation

Detailed Application Scenarios

1. Hydraulic Presses & Stamping Equipment

• Function:

  • Holds press ram in elevated position during die changes and maintenance

  • Maintains clamping force during forming operations without continuous pump pressure

  • Prevents sudden ram drop in case of hydraulic system failure

• Operation: Pilot-operated release allows controlled ram descent via flow control valve

• Safety: Critical for personnel protection; CRG-10 recommended for large press rams, CRG-06 for auxiliary functions

• Configuration: Often paired with counterbalance valves for precise motion control

2. Mobile Elevating Work Platforms (MEWPs) & Aerial Lifts

• Applications:

  • Scissor Lifts: Platform elevation holding and controlled descent

  • Boom Lifts: Telescopic boom extension and articulation holding

  • Cherry Pickers: Basket leveling and rotation control

• Safety Compliance: Meets ANSI/SIA A92 and EN 280 standards for load holding devices

• Advantage: Pilot-operated lowering provides smooth, controlled descent independent of engine speed

• Typical Setup: CRG-06 for mid-size platforms; CRG-10 for heavy-duty construction lifts

3. Injection Molding Machines

• Function:

  • Mold clamping force maintenance during injection and cooling cycles

  • Core pull and slide retention during molding

  • Ejector plate position holding

• Precision: Near-zero leakage ensures consistent clamping force for part quality

• Efficiency: Allows pump de-pressurization during holding periods, reducing energy consumption by 20-30%

• Selection: CRG-03 for small machines (50-150 ton); CRG-06 for medium machines (150-500 ton); CRG-10 for large machines (500+ ton)

4. Construction & Heavy Machinery

• Applications:

  • Excavators: Boom, arm, and bucket position holding during engine-off operation

  • Wheel Loaders: Lift arm and bucket tilt control

  • Dump Trucks: Body hold during transport; controlled tipping via pilot release

  • Concrete Boom Pumps: Boom section holding and controlled positioning

• Durability: Robust construction withstands shock loads and contaminated hydraulic fluid

• Emergency Operation: Manual pilot release option available for lowering loads without power

5. Material Handling & Lifting Equipment

• Applications:

  • Forklifts: Mast tilt and fork positioning hold

  • Overhead Cranes: Hoist load holding and controlled lowering

  • Stackers & Palletizers: Lift carriage position maintenance

  • Dock Levelers: Platform height retention during loading

• Advantage: Prevents load drift during transport; pilot release enables smooth, controlled lowering

6. Machine Tool Hydraulics

• Function:

  • Workpiece clamping force maintenance during machining

  • Counterbalance for vertical axis slides and spindles

  • Tailstock and quill position holding

• Precision: Maintains clamping force without continuous pump operation

• Configuration: CRG-03 for small CNC machines; CRG-06 for machining centers

7. Marine & Offshore Equipment

• Applications:

  • Deck Cranes: Load holding during vessel motion

  • Hatch Covers: Secured closure during sea transit

  • Anchor Windlasses: Chain and anchor holding

  • Steering Gear: Rudder position lock

• Corrosion Resistance: Optional marine-grade coatings and stainless steel components

• Classification: Meets DNV, ABS, and LR marine classification requirements

8. Renewable Energy Systems

• Wind Turbines:

  • Rotor brake holding during maintenance

  • Pitch cylinder position lock for emergency feathering

  • Yaw brake release control

• Solar Tracking: Hydraulic actuator holding for panel positioning

Technical Advantages

• Hardened Steel Poppet & Seat: Precision-lapped metal-to-metal sealing provides near-zero leakage and extended service life

• High Pilot Ratio Options: 4:1 or 8:1 ratios minimize pilot pressure requirements for opening under high loads

• Fast Response: Pilot pressure opens valve within 20-30 ms for immediate load release when required

• Low Pressure Drop: Streamlined flow path minimizes energy loss in forward direction (< 0.3 bar at rated flow)

• Pre-Opening Design: Optional pre-opening feature reduces pressure shock and allows smooth load lowering

• Compact Construction: Threaded body design allows direct installation in hydraulic lines without additional manifold

Installation & Maintenance Notes

• Mounting Orientation: Can be installed in any position; vertical mounting with poppet closing against gravity preferred for maximum holding security

• Pilot Line Filtration: Maintain ISO 4406 18/16/13 cleanliness to prevent pilot orifice blockage

• Back Pressure Consideration: Tank line back pressure affects pilot operation; use external drain option if tank pressure exceeds 20 bar

• Dual Valve Configuration: For double-acting cylinders, install one CRG valve in each line (A and B ports) for holding in both directions

• Pressure Spikes: Install accumulators or dampening orifices in systems with severe pressure spikes to protect seat and poppet

Conclusion

The CRG Series pilot-operated check valves provide the essential combination of secure load holding and controlled hydraulic release required by modern industrial and mobile hydraulic systems. Whether ensuring operator safety in aerial work platforms, maintaining precision in injection molding, securing heavy loads in construction equipment, or providing reliable backup in marine systems, the CRG-03, CRG-06, and CRG-10 deliver consistent performance across a wide range of flow capacities and application requirements. Their robust construction, near-zero leakage, and flexible mounting options make them the preferred choice for hydraulic system designers prioritizing both safety and operational efficiency.