DOUBLE OVERCENTER VALVE FOR OPEN CENTER VBCD

The VBCD series valves are double descent and movement control valves (also known as overcenter). Their action blocks the load and controls its movement in both directions; and are therefore suitable for applications in which it is necessary to control the descent phase of a suspended load subjected to gravitational force and to guarantee stability in the actuator working position in the presence of bidirectional loads, as occurs for example in the reversible hydraulic motors. The pilot line manages the partial opening of the descent channel allowing control of the actuator movement and avoiding the phenomenon of cavitation. The valve also works as 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 VBCD is a not-compensated valve and its use is therefore recommended in systems with DCV with an open center spool. The hydraulic sealing 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. VBCD are parts-in-body valves, 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. VBCD valves are available in size BSPP ¼” to BSPP ¾” for recommended working flow rates up to 120 lpm (32 gpm). Different setting ranges and pilot ratios are available on request as an anti-tampering device. For optimal operation, it is recommended to set the overcenter valves to a value 30% higher than the maximum working load.