1. Product Basic Overview
The SO-H10L-2 is a double pilot-operated check hydraulic lock, commonly known as a hydraulic counterbalance valve. It is specially designed to pair with ZS-L10 series multi-way directional valves. Installed at the execution end of the entire hydraulic system and plumbed into the inlet and outlet lines of hydraulic cylinders and winch hydraulic motor, it delivers long-term load holding and pressure retention via zero-leakage poppet sealing. It eliminates safety hazards such as load free sliding, hook dropping and outrigger retraction, serving as a standard safety valve for cranes, aerial work platforms and drilling rig outrigger circuits. The suffix number 2 stands for the standard tubular version with external threads on both ends.
Model Breakdown
- SO: Series code for double hydraulic lock (balance lock)
- H10: Nominal diameter DN10 (matching G1/2 threaded ports)
- L: Universal structure for plate and tubular mounting
- 2: Standard factory configuration without pressure regulation, purely for locking purposes
2. Core Technical Parameters
Item Specification
Product Type Dual pilot-operated check valve (hydraulic lock type hydraulic counterbalance valve)
Nominal Diameter DN10
Port Connection G1/2 British pipe thread
Rated Working Pressure 32MPa, peak withstand pressure 35MPa
Maximum Rated Flow 50L/min
Valve Body Material Hard anodized aluminum alloy
Sealing Structure Hardened steel poppet with NBR oil-resistant rubber seals
Applicable Fluid ISO VG46 / VG68 anti-wear hydraulic oil
Operating Temperature -20℃ ~ +80℃
Structural Feature Linked push rod for synchronous unlocking of two check valves
Warranty Period 1 year
3. Structure & Working Principle
The valve body integrates two independent one-way poppets and one linked control push rod, connected to the A and B bidirectional oil lines alongside the driving hydraulic motor or double-acting cylinder:
1. Neutral shutdown of main directional valve: Springs compress both poppets to tightly seal the oil passages. Hydraulic oil in the circuit cannot recirculate, locking the hydraulic motor from rotation and fixing the hydraulic cylinder rigidly. No load pressure loss or dropping will occur even if pipelines rupture.
2. Forward oil supply operation: Hydraulic oil enters from port A, forcing open the left poppet for free flow, and simultaneously pushes the internal push rod rightward to pre-unlock the right poppet for smooth oil return from port B, driving the hydraulic motor to rotate forward or the cylinder to extend.
3. Reverse oil supply operation: Repeats the above logic with oil fed from port B; the push rod shifts left to unlock the left poppet to enable reverse movement.
4. Upon oil supply cut-off, the push rod resets immediately, and the two poppets rebound to lock the oil circuit for instant load positioning.
4. Key Product Advantages
1. Hard poppet sealing design delivers extremely low static leakage, maintaining stable pressure holding without load sinking during long stationary parking, ideal for crane outrigger idle placement;
2. Linked push rod ensures high synchronism in bidirectional unlocking, enabling jerk-free and smooth forward/reverse running of the hydraulic motor;
3. Can be mounted at the outlet of multi-way valves or close to the hydraulic motor/cylinders, requiring no pipeline reworking to refit existing hydraulic system;
4. Self-cleaning poppet structure resists hydraulic oil contaminants to prevent jamming, offering outstanding durability on dusty construction and outdoor job sites;
5. Fully mechanical hydraulic construction with no electric components delivers intrinsic explosion-proof performance, suitable for explosion-proof hydraulic system in oilfields and mines.
5. Typical Application Scenarios
1. Locking circuits for four supporting outriggers of truck cranes and mobile cranes to secure support cylinders during parking;
2. Winch hydraulic motor circuits to prevent free falling of hooks under no-load or heavy-load conditions;
3. Anti-fall safety control for hydraulic cylinders of aerial work platforms and lifting equipment;
4. Position-locking circuits for propulsion cylinders and orbital hydraulic motor of drilling rigs and roadheaders;
5. Safety load holding protection for heavy-duty actuators across all engineering machinery hydraulic system.
6. Fault Replacement Instructions
Replace the complete SO-H10L-2 counterbalance valve assembly if loads slide spontaneously, the hydraulic motor coasts freely, pressure dissipates rapidly after locking, or oil seeps from threaded ports. These malfunctions are mainly caused by worn internal poppets and aged failed seals.
