INDUSTRY COMPONENT

Cover Plate

A cover plate is a removable sealing component in pressure vessel manway assemblies that provides access while maintaining structural integrity and pressure containment.

Component Specifications

Definition
The cover plate is a critical safety component in pressure vessel manway assemblies, designed to seal the access opening under internal pressure conditions. It typically consists of a circular or elliptical plate with bolt holes that align with the manway flange, using a gasket to create a pressure-tight seal. The plate must withstand design pressure, temperature, and mechanical loads while allowing for periodic inspection, maintenance, and cleaning of the vessel interior.
Working Principle
The cover plate operates on the principle of bolted flange connection with gasket compression. When bolts are tightened, the gasket between the cover plate and manway flange deforms to fill surface imperfections, creating a leak-tight seal. Under internal pressure, the pressure force acts against the cover plate, which transfers the load through the bolts to the vessel structure. The design ensures uniform gasket compression and proper stress distribution to prevent leakage and structural failure.
Materials
ASTM A516 Grade 70 carbon steel for general service, ASTM A240 Type 316 stainless steel for corrosive environments, or other materials per ASME Section II specifications. Gasket materials include spiral-wound (stainless steel with graphite filler), rubber, or PTFE based on temperature and media compatibility.
Technical Parameters
ParameterTypical rangeNotes & selection driver
Diameter400-600 mm (typical)
Thickness25-50 mm
Surface FinishRa 3.2 μm minimum for gasket seating
Number Of Bolts8-16 (depending on size)
Pressure Rating10-50 bar (design)
Temperature Range-20°C to 300°C
Bolt Circle DiameterAs per flange standard

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

Standards
ASME BPVC Section VIII, ISO 16528, DIN 28011

Parent Products

This component is used in the following industrial products

Engineering Analysis

Risks & Mitigation
  • Gasket failure leading to pressure leakage
  • Improper bolt torque causing uneven sealing
  • Corrosion reducing structural integrity
  • Fatigue cracking from cyclic loading
FMEA Triads
Trigger: Insufficient bolt preload
Failure: Gasket compression loss and leakage
Mitigation: Implement torque control procedures and use calibrated torque wrenches
Trigger: Corrosion from process media
Failure: Reduced plate thickness and structural failure
Mitigation: Select corrosion-resistant materials and implement regular thickness testing

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance
Flatness tolerance within 0.5 mm across sealing surface, bolt hole positional tolerance ±0.8 mm
Test Method
Hydrostatic pressure test at 1.5x design pressure, helium leak test for critical applications, visual inspection per ASME Section V

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.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Cover Plate

4 companies list this product among what they make. Company figures are quoted from each company's own website; every card states where the relationship came from.

Xiamen Apollo Stamping Welding Technology Co., Ltd
Xiamen, Fujian, CN
Founded 2010200 staff
IATF16949:2016 ISO9000 oHS/Reach
Listed on the company's own website · profile compiled by CNFX from public sources
Aier Ventilation
Shanghai, CN
Also makes: Access Doors, HVAC Systems, Gate Assembly and 2 more
Listed on the company's own website · profile compiled by CNFX from public sources
Cixi Wanjie Electronic Co., Ltd.
Zhejiang, CN
Also makes: Terminal Block
Listed on the company's own website · profile compiled by CNFX from public sources
DGCRANE
Henan, CN
Listed on the company's own website · profile compiled by CNFX from public sources

Manufacturer listings support early research and capability understanding. They are not certification, ranking, or transaction guarantees.

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Frequently Asked Questions

What is the difference between a cover plate and a blind flange in pressure vessels?

A cover plate is specifically designed for manway access with features like lifting lugs and hinge points for easy removal, while a blind flange is a permanent closure without access functionality. Cover plates have reinforced construction for frequent opening/closing cycles.

How often should cover plate gaskets be replaced?

Gaskets should be replaced every time the cover plate is opened, or according to manufacturer specifications. Visual inspection for compression set, cracks, or chemical degradation should be performed during maintenance intervals.

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.

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