SV20GA1-4X/12

The SV20GA1-4X/12 check valve belongs to the Hy-Check Valves series from Bosch Rexroth and manages directional flow in hydraulic circuits. It uses a threaded connection, allowing direct installation into manifolds without welding. The threads follow the UNF/UN standard defined by ANSI/ASME B1.1, so they mate with commonly available fittings. A nominal size of 20 aligns the internal passage area with medium-capacity lines in industrial equipment. The valve withstands a maximum operating pressure of 315 bar, letting it function alongside high-pressure pumps and actuators. A cracking pressure of 2.5 bar defines the point at which flow begins, protecting downstream components from unintended reverse flow. The design includes a pre-opening feature, so flow is initiated smoothly and pressure spikes during start-up are reduced. In threaded form the unit weighs 5.4 kg, a mass suitable for direct mounting without additional supports.

Control area A1 of 3.46 cm² determines the pilot force required to shift the internal poppet when pressure is applied to port A1. A larger control area A3 of 10.17 cm² allows lower pilot pressure to hold the valve fully open during continuous flow. The smaller control area A4 of 1.13 cm² provides rapid closure when pilot pressure is released, restoring check function quickly. Pilot oil is returned internally, eliminating the need for an external drain line and simplifying piping. Pilot pressure can be as high as 315 bar, enabling remote actuation under full system pressure, while a minimum of 5 bar is required to initiate pilot opening. Port X encloses a pilot volume of 10.8 cm³, giving sufficient oil capacity for stable control without noticeable lag. The valve should receive fluid with cleanliness level 20/18/15 per ISO 4406, preventing contamination-related wear on sealing surfaces.