SF Prefill Valves

The Bosch Rexroth SF Prefill Valves are large-sized, pilot-operated check valves designed for flange or threaded connection directly onto the cylinder. They work by allowing a large volume of low-pressure fluid from the tank to quickly fill and prefill a hydraulic cylinder during the retraction or "no-load" stroke, typically for a forming press. The key functions are to quickly fill and empty the cylinder's main chamber and to provide leakage-free blocking of the fluid under high pressure. This is essential for minimizing cycle times and energy consumption in press applications. Optional versions are available with a pre-decompression feature to dampen pressure release and reduce switching noise and shocks.