Manway Cover: Temperature Range -50°C to 300°C, Weight 15-50 kg

Q: How often should manway covers be inspected?

Visual inspection every 6 months for corrosion or deformation; non-destructive testing (ultrasonic thickness) annually; full pressure testing during major maintenance every 3-5 years or as per RBI programs.

Q: Can manway covers be customized for high-pressure applications?

Yes, designs include reinforced elliptical shapes, increased thickness, specialized alloys (Inconel, duplex steels), and advanced sealing (metal O-rings) for pressures exceeding 1000 psi.

Component Specifications

Definition

A manway cover is a critical safety and access component installed on manways (access openings) of pressure vessels, storage tanks, reactors, boilers, and similar industrial equipment. It functions as a sealed, pressure-retaining barrier that can be removed to allow personnel entry, equipment insertion, or visual inspection of the interior. Designs vary from simple bolted flat plates to complex hinged or quick-opening mechanisms with integrated safety interlocks. The cover must maintain structural integrity under operating pressures, temperatures, and environmental conditions while ensuring leak-tight sealing.

Working Principle

The manway cover operates by creating a mechanical seal against a mating flange on the vessel opening. When closed and secured (typically with bolts, clamps, or locking mechanisms), it distributes pressure loads evenly across the sealing gasket and vessel structure. The cover's geometry (flat, dished, or elliptical) and reinforcement (ribs or increased thickness) counteract internal pressure forces. Safety features may include pressure relief devices, locking pins to prevent accidental opening under pressure, and alignment guides for proper installation. The working principle ensures the cover remains securely closed during operation while allowing safe, controlled access during maintenance shutdowns.

Materials

Carbon steel (ASTM A516 Gr. 70), stainless steel (304/316L), alloy steel (SA-387 Gr. 11), aluminum alloys, or composite materials. Selection depends on service conditions: pressure rating (ASME Section VIII Div. 1), temperature range (-20°C to 400°C typical), corrosion resistance (NACE MR0175 for sour service), and mechanical properties (yield strength ≥ 240 MPa for standard applications). Gaskets: spiral-wound (stainless steel/graphite), rubber (EPDM, Viton), or PTFE-based.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Weight	15-50 kg
Coating	Epoxy paint, galvanized, or passivation
Diameter	400-600 mm (standard)
Bolt Pattern	8-16 bolts (ASME B16.5)
Sealing Type	Raised face (RF) or ring-type joint (RTJ)
Surface Finish	125-250 Ra μm
Pressure Rating	10-150 psi (0.7-10.3 bar)
Temperature Range	-50°C to 300°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 14122-4, ASME BPVC Section VIII, DIN 28011, PED 2014/68/EU

Parent Products

This component is used in the following industrial products

Manway

A sealed access opening in a pressure vessel for inspection, maintenance, and cleaning.

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Engineering Analysis

Risks & Mitigation

Catastrophic failure if opened under pressure
Gasket leakage leading to product loss or toxicity exposure
Corrosion-induced thinning reducing pressure rating
Misalignment causing seal failure
Bolt fatigue or over-torquing

FMEA Triads

Trigger: Incorrect bolt torque during installation
Failure: Uneven gasket compression and leakage
Mitigation: Use calibrated torque wrenches and follow cross-tightening patterns per ASME PCC-1

Trigger: Corrosion in aggressive chemical environments
Failure: Reduced wall thickness and potential rupture
Mitigation: Material upgrade to stainless steel/alloys, protective coatings, and regular thickness monitoring

Trigger: Human error attempting to open under pressure
Failure: Violent ejection causing injury
Mitigation: Install pressure indicators and mechanical interlocks (ASME/ANSI B15.1)

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Flatness tolerance ≤0.5 mm per 300 mm, bolt hole alignment ±1 mm, surface roughness 125-250 μm Ra for gasket seating

Test Method

Hydrostatic/pneumatic pressure test per ASME Section VIII, helium leak test for high-integrity applications, dye penetrant inspection for weld seams

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 Manway Cover

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

Wenzhou Deyi Machinery

Wenzhou, Zhejiang, CN

Also makes: Sanitary Centrifugal Pump, Dairy Flow Control Diaphragm Valve, Safety Relief Valve and 9 more

Listed on the company's own website · profile compiled by CNFX from public sources

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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 manway cover and a handhole cover?

Manway covers are larger (typically ≥400 mm) to allow personnel entry, while handhole covers are smaller (<150 mm) for inspection or tool access only. Manways require structural design for pressure retention and safety interlocks.

How often should manway covers be inspected?