Safety Valves

Pressure Safety Relief Valve WCB 3 x 4 Class 150 — Slop Oil Service

Supreme Valves conventional spring-loaded pressure safety relief valve for slop oil and crude hydrocarbon service. Full-nozzle, full-lift design with WCB body, CF8 nozzle and trim, Type 304 disc, set at 16.5 bar(g), orifice K, 3 inch Class 150 RF inlet and 4 inch Class 150 RF outlet. Sized per API 520 for liquid relief; manufactured and tested to API 526 and API 527.

Key Applications

Slop Oil ProcessingCrude Oil Pump DischargeRefinery Storage TanksPetrochemical Overpressure Protection
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Industrial Applications & Engineering Problem Solving

The Engineering Challenge

Slop oil and crude pump discharge lines operate between 8 and 15 bar with intermittent pressure spikes from batch transfers, thermal expansion, and downstream valve closures. Without a correctly sized pressure safety relief valve, piping and vessels are exposed to overpressure that can damage seals, instruments, and downstream equipment.

The Supreme Valves India Engineering Solution

Supreme Valves supplies a conventional full-nozzle pressure safety relief valve in ASTM A216 WCB with CF8 nozzle and Type 304 disc, set at 16.5 bar(g) and sized to orifice K for 149,530 kg/hr liquid relief capacity on slop oil service. The valve is manufactured, set, and tested at our works to API 526 and API 527.

Operational Use Cases & Scenarios

Slop Oil / Crude Processing

Outlet Pump Line Thermal and Blocked-Discharge Protection

Operational Challenge: Protecting pump discharge piping and vessels when downstream isolation or batch transfer causes pressure to rise above normal operating range on slop oil service.

Engineering Benefit: Spring-loaded full-lift relief at 16.5 bar(g) limits overpressure before equipment design limits are exceeded.

Refinery Tank Farm

Storage Tank and Transfer Header Overpressure Relief

Operational Challenge: Providing a flanged Class 150 relief path on existing 3 inch headers handling crude and slop oil mixtures at ambient to 80 deg C.

Engineering Benefit: 3 inch x 4 inch Class 150 RF configuration fits standard ANSI piping with API 526 interchangeability.

Technical Specifications

Valve Type Conventional spring-loaded pressure safety relief valve, full nozzle, full lift, closed bonnet
Design Standard API 526
Sizing Standard API 520 Part I (liquid service)
Testing Standard API 527 seat tightness
Inlet Size / Rating 3 inch (DN80), ASME Class 150, raised face
Outlet Size / Rating 4 inch (DN100), ASME Class 150, raised face
End Connection Flanged to ASME B16.5
Set Pressure 16.5 bar(g)
Relieving Pressure 18.15 bar(g) at 10% overpressure
Operating Pressure 8.0 to 15.0 bar(g)
Operating Temperature 50 to 80 deg C
Service Fluid Slop oil (crude oil), liquid phase
Orifice Designation K
Orifice Diameter 38.8 mm (1.838 sq in selected area)
Rated Discharge Capacity 149,530 kg/hr at relieving conditions
Accessories Packed lifting lever, screwed cap
Manufacturer Supreme Valves India

Material of Construction (MOC)

Component / Part Available Materials
Body ASTM A216 Gr. WCB
Bonnet / Cap ASTM A216 Gr. WCB
Nozzle / Nozzle Ring ASTM A351 Gr. CF8
Disc Type 304 stainless steel
Disc Holder / Guide ASTM A351 Gr. CF8
Stem / Adjusting Screw Type 410 stainless steel
Setting Spring Carbon steel
Studs / Nuts ASTM A193 Gr. B7 / ASTM A194 Gr. 2H
Gasket Aramid fibre, non-asbestos
Lifting Lever Carbon steel, packed type

Dimensions & Weights

Inlet x OutletSet Pressure (bar g)OrificeApprox. Width A (mm)Approx. Height B (mm)Approx. Face-to-Face C (mm)
3" x 4" Class 150 RF16.5K / 38.8 mm156162674

Service Media

Slop Oil (Crude Oil)Liquid Hydrocarbon

Purchase Options

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Features & Benefits

API 526 Conventional Full-Nozzle Design

Full-nozzle, full-lift spring-loaded construction provides rated relieving capacity on liquid hydrocarbon service with metal-to-metal seat per API 527.

WCB Body with Stainless Trim

Cast carbon steel ASTM A216 WCB body and bonnet for hydrocarbon duty, with CF8 nozzle and Type 304 disc for corrosion resistance at the seat interface.

Sized for Slop Oil Liquid Relief

Orifice K selected for 149,530 kg/hr rated capacity at 18.15 bar(g) relieving pressure and 80 deg C on slop oil liquid service per API 520.

Set and Tested at Works

Each valve set at 16.5 bar(g), seat-tested per API 527, and supplied with EN 10204 3.1 material test certificates and set pressure test certificate.

Frequently Asked Questions

Q What set pressure is this valve supplied at?

This configuration is set at 16.5 bar(g), which is more than 10% above the maximum stated operating pressure of 15 bar(g), as required for liquid relief service on slop oil lines.

Q Is this valve suitable for crude oil and slop oil service?

Yes. The WCB body with CF8 nozzle and Type 304 disc is suited to slop oil and crude hydrocarbon liquid service at 50 to 80 deg C and 8 to 15 bar operating pressure.

Q What certifications are supplied?

EN 10204 3.1 material test certificates for pressure-retaining parts, set pressure test certificate, seat tightness report per API 527, hydrostatic test certificate, and certificate of conformance from Supreme Valves India.

Q Can the set pressure or orifice be changed?

Other set pressures and orifice designations can be offered against confirmed process data including relieving rate, fluid density, viscosity, and back pressure. Contact our sales team with complete API 520 sizing inputs.

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Submit a detailed RFQ with size, class, material, and quantity. Our engineering team responds within 24 hours.

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