SV20GB1-4X/V/12

The SV20GB1-4X/V/12 check valve is manufactured by Bosch Rexroth within the Hy-Check Valves series. It serves as a line-mounted blocking element that permits free flow in one direction and shuts off reverse flow in hydraulic automation circuits. The unit is built with a nominal size 20 passage to accommodate medium-to-high flow volumes without excessive pressure drop. A threaded connection format simplifies installation in manifolds or pipe runs, and the main A and B ports use a 1 5/16-12 UN thread that matches common SAE fittings. An opening pressure of 2.5 bar keeps the poppet seated until the upstream pressure exceeds this level, while the design includes no pre-opening feature, so the valve remains fully closed until that threshold is reached. Continuous operating service is allowed up to 315 bar, aligning the valve with typical system pressures in presses and mobile machinery. Minimum fluid temperature of −15 °C and maximum of +80 °C, when used with FKM seals, define the thermal window for mineral or synthetic oils. The FKM sealing elements resist swelling and provide low compression set under these temperatures.

Auxiliary functions are handled through pilot ports, where the X and Y connections are threaded 7/16-20 UNF to accept small diameter control lines that can open the poppet from the downstream side. The pilot circuit requires at least 5 bar to override the check element and may be loaded to a maximum of 315 bar without damaging internal parts; a pilot volume of 10.8 cm³ must be filled to achieve full actuation, which influences response time in fast cycling loops. Acceptable oil viscosity extends up to 500 mm²/s, allowing the valve to function with cold start fluids or high-viscosity specialized media. System cleanliness should not exceed ISO 4406 20/18/15 to prevent contaminant related wear on the seating surfaces. The threaded housing weighs 5.4 kg, making it manageable for single-person installation yet robust enough to absorb hydraulic shocks common in industrial presses and steering circuits.