SUN HYDRAULICS
RPKSKBN

***Disclaimer: The following summary contains information gathered from various sources such as product descriptions, technical specifications and catalogs. While efforts have been made to provide accurate details, inaccuracies may occur. It is advised to verify all information by contacting Sun Hydraulics directly.***
The Sun Hydraulics RPKSKBN (RPKSKBN) is a pilot-operated, balanced-poppet relief cartridge designed for pressure regulation in hydraulic systems. These normally closed valves open to tank port 2 when the inlet port 1 pressure reaches the valve setting, effectively throttling flow to maintain consistent pressure. Notably, these valves are recognized for their accuracy, smooth operation, quiet performance, rapid response, and minimal pressure rise relative to flow. The internal modulating mechanism ensures immunity to cavitation-related issues such as noise and manifold erosion. Capable of handling maximum pressure at port 2, this valve is suitable for cross-port relief circuits and remains relatively unaffected by fluctuating oil temperatures or contamination. It features a main stage orifice protected by a 150-micron stainless steel screen and exhibits back pressure on tank port 2 that directly adds to the valve setting at a 1:1 ratio. The RPKSKBN model offers adjustable settings throughout its range using W or Y controls unless specified otherwise. Corrosion-resistant options are available with external stainless steel components (suffix AP) or zinc-nickel plating (suffix LH). Constructed with Sun's floating style design, this cartridge minimizes risks of internal binding from excessive installation torque or machining variations. The valve fits into Cavity T-18A Series 4 with a capacity of up to 200 gpm (760 L/min) and operates under maximum pressures of 5000 psi (350 bar). Typical response time is about 7 ms with maximum leakage at reseat limited to 10 drops/min (0.7 cc/min). Installation specifications include a hex size of 1-5/8 inches (41.3 mm), installation torque between 350-375 lbf ft (474-508 Nm), and an adjustment screw internal hex size of 5/32 inches (4 mm). The model weighs approximately 2.50 lb (1.15 kg) and uses Viton seal kit number 990318006 for maintenance purposes.