Product Overview

The Kobelco Minimum Pressure Valve Assembly (Drawing Numbers: S-FC12-503, S-FC12-504, and SC-FC12-505) is an essential pressure control component designed for Kobelco rotary screw air compressors. Installed at the outlet of the oil-gas separator, it ensures that minimum lubrication pressure is rapidly established upon startup and maintained throughout continuous operation.

This valve also incorporates an integrated non-return (check valve) function to prevent compressed air from flowing backward into the compressor air end during unloading or shutdown, protecting internal air-oil separator elements and ensuring system reliability.

Key Features & Benefits

• Fast Pressure Building: Maintains minimum system pressure (approx. 4–4.5 bar) during startup to ensure proper lubricant circulation.

• Integrated Non-Return Protection: Prevents compressed air backflow from the air receiver tank when the compressor unloads or stops.

• 100% Direct-Fit Specification: Precision-machined valve body and flange dimensions designed for seamless plug-and-play installation on Kobelco units.

• Heavy-Duty Corrosion & Wear Resistance: Crafted with high-grade alloy valve bodies, fatigue-resistant springs, and fluororubber seals to endure thermal shock and high flow velocity.

Technical Specifications

Common Failure Symptoms (When to Replace or Overhaul?)

• Slow Pressure Buildup on Startup: Internal spring fatigue or valve piston sticking open, causing delayed lubrication.

• Air Tank Discharge Backflow Upon Shutdown: Check valve disc/O-ring wear allowing system air pressure to vent back into the machine.

• Continuous Air Venting / Internal Leakage: Degraded internal seal rings causing pressure fluctuations during loading cycles.