Bonnet / Door: Temperature Range -20°C to 120°C

Component Specifications

Definition

The bonnet/door is a critical structural component of a ram preventer in blowout prevention (BOP) systems, designed to seal the ram cavity and provide access for ram replacement or maintenance. It withstands high-pressure drilling fluids and wellbore pressures while ensuring operational safety through robust sealing mechanisms and locking systems.

Working Principle

The bonnet/door operates as a pressure-retaining closure that seals against the ram preventer body using metal-to-metal seals or elastomeric gaskets. It is secured with bolts or hydraulic locking mechanisms to maintain integrity under extreme pressures, allowing safe isolation of the ram assembly during maintenance without depressurizing the entire BOP stack.

Materials

Forged or cast low-alloy steel (e.g., AISI 4130, 4140) or stainless steel (e.g., 316L), heat-treated for high strength and corrosion resistance, with hardness typically 22-32 HRC. Sealing surfaces may include nickel or chrome plating for wear resistance.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Bore Size	7-1/16" to 18-3/4"
Seal Type	Metal ring gasket or elastomeric
Connection	API flange or clamp hub
Pressure Rating	5000-15000 psi
Temperature Range	-20°C to 120°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

API 16A, ISO 13533, ASME BPVC Section VIII

Parent Products

This component is used in the following industrial products

Ram Preventer

A critical safety component within a Blowout Preventer (BOP) stack that uses hydraulically actuated rams to seal around drill pipe or completely close the wellbore to prevent uncontrolled release of formation fluids.

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Engineering Analysis

Risks & Mitigation

Seal failure leading to pressure leaks
Structural fatigue from cyclic loading
Corrosion in harsh environments
Improper bolting causing uneven stress

FMEA Triads

Trigger: Seal degradation due to temperature extremes
Failure: Pressure leakage during operation
Mitigation: Use temperature-resistant seals and regular inspection

Trigger: Bolt torque loss from vibration
Failure: Bonnet displacement under pressure
Mitigation: Implement torque monitoring and locking devices

Industrial Ecosystem

Compatible With

Hydril, Shaffer, Cameron ram preventers

Typical Suppliers & Equivalents

Manufacturer-specific bonnets with matching pressure ratings and bore sizes

Compliance & Inspection

Tolerance

Flatness within 0.05 mm per 300 mm, surface finish Ra ≤ 3.2 μm for sealing areas

Test Method

Hydrostatic pressure testing per API 16A at 1.5x working pressure for 30 minutes

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 Bonnet / Door

Manufacturer profiles associated with Bonnet / Door.

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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 primary function of a ram preventer bonnet?

To provide a pressure-tight seal for the ram cavity, allowing safe access for maintenance while containing wellbore pressures during drilling operations.

How often should bonnet seals be inspected?

Seals should be inspected during every BOP maintenance cycle (typically every 3-5 years) or after any pressure test failure, following API RP 53 guidelines.

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.

Bonnet / Door