INDUSTRY COMPONENT

Disc/Seat

Disc/Seat is the sealing interface in pressure relief valves that controls fluid flow and prevents overpressure.

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Component Specifications

Definition
The Disc/Seat assembly in a pressure relief valve consists of two precisely engineered components: the disc (or poppet) that moves to open or close the flow path, and the seat—a stationary ring or surface that provides a sealing surface for the disc. This critical interface maintains system pressure within safe limits by allowing controlled release of excess pressure when predetermined setpoints are exceeded. The sealing quality directly determines valve leakage rates, reseat pressure, and overall system safety.
Working Principle
When system pressure exceeds the valve's set pressure, the disc lifts from the seat, creating a flow path for fluid release. As pressure drops below reseat pressure, spring force returns the disc to contact the seat, re-establishing the seal. The disc-seat geometry (flat, conical, or nozzle-type) determines flow characteristics, blowdown, and stability.
Materials
Typically hardened stainless steel (AISI 410, 316), stellite alloys, or ceramic coatings for wear resistance. Seats may incorporate elastomeric inserts (Viton, EPDM) for bubble-tight seals in low-pressure applications.
Technical Parameters
  • Leakage Class ANSI/FCI 70-2 Class IV or better
  • Seat Diameter DN15-DN200
  • Surface Finish Ra ≤ 0.4 μm
  • Temperature Range -50°C to 400°C
  • Set Pressure Range 0.5-300 bar
Standards
ISO 4126, ASME BPVC Section VIII, API 526, DIN 3320

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Disc/Seat.

pressure relief valve disc valve seat safety valve components industrial sealing surfaces ASME valve parts FMEA valve failure Disc/Seat Disc/Seat in Machinery and Equipment Manufacturing

Parent Products

This component is used in the following industrial products

Pressure Relief Valve

A safety device that automatically releases excess pressure from a system to prevent equipment damage or failure.

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Engineering Analysis

Risks & Mitigation
  • Catastrophic overpressure if sealing fails
  • Process contamination from leakage
  • Unplanned downtime during replacement
FMEA Triads
Trigger: Abrasive particles in fluid stream
Failure: Erosion of sealing surfaces causing increased leakage
Mitigation: Install upstream filters; specify hardened materials (stellite); implement regular fluid analysis
Trigger: Thermal cycling beyond design limits
Failure: Distortion/misalignment preventing proper resealing
Mitigation: Select materials with matched thermal expansion; install thermal shields; monitor temperature gradients

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
Seat flatness ≤ 0.025mm; concentricity ≤ 0.05mm TIR
Test Method
Hydrostatic seat test per API 527; bubble-tight test with inert gas at 90% set pressure

Procurement Evaluation Criteria

Not customer reviews or live demand data. These dimensions support RFQ preparation and supplier evaluation.

Technical documentation
4/5
Manufacturing capability
4/5
Inspection readiness
5/5
Supplier transparency
3/5

These scores are example evaluation dimensions, not real customer ratings, country-specific buyer feedback, or live inquiry activity.

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Frequently Asked Questions

What causes disc/seat leakage in pressure relief valves?

Common causes include: wear from particulate erosion, corrosion damage, thermal distortion, improper installation alignment, and seal degradation from chemical attack or extreme temperatures.

How often should disc/seat assemblies be inspected?

Inspect during annual valve testing per ASME requirements. High-cycle or corrosive service may require quarterly inspections. Replace if leakage exceeds manufacturer specifications or visible damage exceeds 0.1mm depth.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

Data Basis

CNFX manufacturer profiles, technical classification, publicly available product information, and ongoing plausibility checks.

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.

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