SL30PA1-4X/

The SL30PA1-4X/ check valve belongs to the Hy-Check Valves series from Bosch Rexroth and serves hydraulic automation loops by permitting free flow in one direction and blocking reverse flow until a pilot signal opens the poppet. Subplate mounting simplifies installation on manifold bases and supports rapid maintenance. A nominal size of NG32 provides a flow path large enough for medium-to-high capacity systems. The valve tolerates operating pressures up to 315 bar so it can be used in high-pressure lines of presses or injection machines. A cracking pressure of 2.5 bar ensures the poppet seats firmly yet opens with minimal upstream loss. When a pilot line reaches at least 5 bar, the internal actuator shifts, overriding the check function for bidirectional flow. A maximum flow rating of 550 L/min keeps velocity within acceptable limits, and the ISO 5781-09-13-0-16 porting pattern aligns the body with standard manifold cavities. The pre-opening feature reduces switching shock by bleeding oil before full opening.

The external pilot oil return designated as port Y discharges control oil to tank, avoiding backpressure that could delay closure. Pilot volumes of 19.27 cm³ at port X and 17.5 cm³ at port Y specify the oil required to shift the poppet, so pilot lines can be sized for consistent response times. NBR sealing material maintains leak-tight operation with common mineral fluids and supports temperatures from −20 °C to +80 °C. Exposure within those temperature limits prevents seal hardening or swelling that would disturb seating performance. The design accepts viscosities up to 500 mm²/s, allowing cold-start operation without sticking. If fluid viscosity rises beyond the specified limit, pilot flow can become sluggish and extend actuation time. A weight of 7.8 kg provides sufficient mass to resist line vibration and hold the valve firmly on the manifold. The mass also dampens hydraulic shocks transferred through the mounting screws.