FUKUI SL431 Spring-Loaded Safety Relief Valve - 1985

The FUKUI SL431 is a precision-engineered spring-loaded safety relief valve manufactured by FUKUI SEISAKUSHO CO., LTD. in Japan, designed to protect pressurized systems from overpressure conditions. Based on API 526 and API 520 standards, the SL431 model is typically available in angle or straight pattern configurations, with flanged connections conforming to ANSI or JIS standards, ensuring compatibility across global piping systems.

This relief valve operates via direct spring actuation, opening once system pressure exceeds the preset limit. It features a metal-to-metal seat or optional soft seat (PTFE/elastomer) for tight shutoff, and can be configured with either an open or closed bonnet depending on service type (gas, steam, or liquid). The body is typically carbon steel or stainless steel, while the trim is made from hardened stainless steel, ensuring durability and high-temperature resistance.

The set pressure is customizable per client requirements (commonly from 1 bar to 100+ bar), with the design pressure rated up to 150 bar and temperature tolerance up to 400°C, depending on construction materials. Designed for low back pressure tolerance, the SL431 valve ensures reliable blowdown control (typically 7%–10%) and safety performance under extreme process conditions. All units undergo factory hydrostatic and set pressure testing in compliance with ASME Section VIII, JIS, or ISO codes and are CE/PED certified.

Specifications:
– Manufacturer: FUKUI SEISAKUSHO CO., LTD.
– Country of Origin: Japan
– Model / Type: SL431
– Serial Number: 31A2051
– Valve Type: Spring-loaded Safety Relief Valve
– Operation: Direct spring-actuated overpressure relief
– Design Pattern: Angle or Straight (based on order)
– Valve Body Material: Carbon Steel / Stainless Steel / Alloy Steel
– Trim Material: Hardened Stainless Steel or equivalent
– Seat Type: Metal-to-metal or optional soft seat (PTFE/elastomer)
– Connection Type: Flanged (ANSI or JIS standards)
– Size Range (Est.): 1" to 4" (exact bore per nameplate)
– Discharge Configuration: Open or Closed Bonnet
– Set Pressure Range: Typically 1 bar to 100+ bar (custom-set)
– Design Pressure: Up to 150 bar
– Temperature Rating: Up to 400°C (material-dependent)
– Blowdown Adjustment: Typically 7%–10%
– Back Pressure Tolerance: Atmospheric or low backpressure
– Design Standards: API 526 / API 520
– Design Codes: ASME Section VIII / JIS / ISO (as specified)
– Certifications: CE / PED (Pressure Equipment Directive)
– Testing: Hydrostatic and Set Pressure Factory Tested

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