Counterbalance valves

Single counterbalance valve for closed center VCLH

In stock

Overcenter valve simple effect semi-compensated with single flanging (load)


Through the Oleoweb VCLH balancing valves it is possible to support suspended loads and control their movement during the descent, eliminating vibrations or lowering too fast and which could generate dangerous situations. The VCLH valve is equipped with BSPP-GAS threaded ports for the connection of the hydraulic pipes, while a flanging surface allows the connection of the load line directly on the cylinder.

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The single overcenter valves of the VCLH series are designed to ensure the stability in the working position of a hydraulic actuator with suspended load, and to control its movement in only one direction (usually the descent phase), leaving the opposite side powered by free flow; thanks to the BSPP-GAS threaded ports, it can be installed in-line into the hydraulic system. The flanged surface allows to install the valve directly on the cylinder, on the load line. By feeding the line opposite the load, the pilot line manages the partial opening of the descent channel allowing control of the actuator movement and avoiding the phenomenon of cavitation thanks to the action of contrasting the gravitational force. A calibrated hole dampens the pilot signal so that the valve opens and closes proportionally, avoiding load oscillations. The VCLH single overcenter valve also works as an antishock valve in the presence of pressure peaks caused by impacts or excessive loads. For this to be possible, the return line on the distributor must be connected to the drain. The VCLH is a semi-compensated valve: any residual pressures on the return line doesn’t affect the setting of the valve while increases the piloting values. The use of this type of valve is therefore possible in systems with DCV with a closed center spool. The hydraulic leakproof is a fundamental feature for the overcenter valves. To ensure the best performance, Oleoweb manufactures the internal components of its valves in high-strength steel, hardened and grinded, and, during the production process, carefully checks the dimensions and geometric tolerances of the sealing elements, as well as the seal itself on the assembled valve. VCLH are parts-in-body valves: all components are housed inside a hydraulic manifold, a solution that allows to manage high flow rates while limiting overall dimensions. The manifold is made of steel for operating pressures up to 350 bar (5075 PSI) and high wear resistance; it is protected from corrosion by zinc plating treatment and it is machined on the six faces for a more effective execution of the surface treatment. For applications exposed to particularly aggressive corrosive agents (e.g. marine applications) Zinc-Nickel treatment is available on request. VCLH valves are available in size BSPP 3/8" for recommended working flow rates up to 40 lpm (10,6 gpm). Different calibration fields and pilot ratios. For optimal operation, it is recommended to set the overcenter valves to a value 30% higher than the maximum working load.

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