Counterbalance valves

Single counterbalance valve for closed center VCCB

In stock

Overcenter valve simple effect semi-compensated with banjo bolt


Thanks to the Oleoweb VCCB counterbalance valves it is possible to manage suspended loads and control their movement by eliminating vibrations or sudden and dangerous lowerings. The banjo bolt on the body valve simplifies the installation and makes the action of the valve more effective.

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Details

The single overcenter valves of the VCCB 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 housing for a banjo bolt on the valve body, they can be installed directly on the cylinder head, simplifying the circuit in favor of assembly times, and optimizing performance thanks to the containment of the hysteresis phenomenon. The fitting bolt must be installed on the cylinder return 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 VCCB 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 VCCB is a semi-compensated valve: residual pressures on the return line don’t affect the setting of the valve while they increase 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. VCCB 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) 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. VCCB 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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