Disc/Plug: Set Pressure Range 0.1-100 bar, Diameter 10-200 mm

Component Specifications

Definition

The Disc/Plug is a precision-engineered component in pressure relief valves that serves as the primary sealing and pressure-release mechanism. It consists of a disc-shaped or plug-shaped element that seats against a valve seat under normal operating conditions. When system pressure exceeds the predetermined set pressure, the disc/plug lifts off the seat, allowing fluid or gas to escape and relieve pressure. The component must maintain tight sealing during normal operation while responding precisely to pressure changes to prevent system damage or failure.

Working Principle

The Disc/Plug operates on the principle of force balance. Under normal conditions, spring force and system pressure keep the disc/plug seated against the valve seat, creating a seal. When pressure exceeds the set point, the upward force from the pressure overcomes the downward spring force, causing the disc/plug to lift. This creates an opening for pressure relief. Once pressure drops below the reseat pressure, the spring force pushes the disc/plug back onto the seat, resealing the valve.

Materials

Typically manufactured from corrosion-resistant materials such as stainless steel (304, 316), brass, or specialized alloys. Sealing surfaces may include elastomers like Viton, EPDM, or PTFE for enhanced sealing. High-temperature applications may use Inconel or other nickel-based alloys.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Diameter	10-200 mm
Lift Height	5-25% of seat diameter
Leakage Class	ANSI/FCI 70-2 Class IV-VI
Pressure Class	ANSI 150-2500, PN10-PN400
Set Pressure Range	0.1-100 bar
Operating Temperature	-40°C to 400°C

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 4126, ASME BPVC Section VIII, API 526, DIN 3320

Parent Products

This component is used in the following industrial products

Pressure Relief Valves

Safety devices that automatically release excess pressure from sterile air distribution systems to prevent overpressure damage.

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Vent/Exhaust Valve

A valve designed to release gases or vapors from a purge system to maintain pressure balance and prevent overpressure.

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Engineering Analysis

Risks & Mitigation

Seal failure leading to leakage
Sticking due to corrosion or contamination
Inaccurate pressure setting
Fatigue failure from cyclic operation
Thermal expansion mismatch

FMEA Triads

Trigger: Corrosion or erosion of sealing surfaces
Failure: Leakage during normal operation
Mitigation: Use corrosion-resistant materials, regular inspection, protective coatings

Trigger: Contamination or fouling
Failure: Disc/plug sticking, failure to open at set pressure
Mitigation: Install filters/strainers, regular maintenance, proper system flushing

Trigger: Spring fatigue or set point drift
Failure: Inaccurate relief pressure
Mitigation: Regular calibration, use of certified springs, temperature compensation

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Seating surface flatness within 0.0005 inches per inch, surface finish 16-32 microinches Ra

Test Method

Hydrostatic/pneumatic seat leakage test per API 527, set pressure verification per ASME PTC 25

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

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Manufacturers of Disc/Plug

Manufacturer profiles associated with Disc/Plug.

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What is the difference between a disc and a plug in pressure relief valves?

A disc is typically flat and seats against a flat or angled seat, while a plug is conical and fits into a matching seat. Discs are common in conventional relief valves, while plugs are often used in pilot-operated valves. Both serve the same function but have different geometric designs.

How often should disc/plug components be inspected or replaced?

Inspection frequency depends on service conditions. Generally, inspect annually or after every relief event. Replace if there is visible wear, corrosion, or damage to sealing surfaces. Follow manufacturer recommendations and regulatory requirements for specific applications.

Can disc/plug components be repaired or must they be replaced?

Minor surface imperfections can sometimes be repaired by lapping or machining, but this requires specialized equipment and expertise. Significant damage, corrosion, or wear typically requires replacement to ensure proper sealing and safety performance.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Disc/Plug