Metal Bellows: Stroke Length 8-20mm, Operating Voltage 12-40kV

Component Specifications

Definition

A precision-engineered flexible metal bellows component designed specifically for medium voltage vacuum interrupter modules. It provides hermetic sealing between moving and stationary parts while maintaining electrical insulation and allowing controlled axial movement during circuit breaker operation. The bellows accommodates thermal expansion, mechanical stress, and maintains vacuum integrity throughout the operational lifecycle.

Working Principle

The metal bellows operates on the principle of controlled elastic deformation through its convoluted structure. During circuit breaker operation, it compresses and extends axially while maintaining a hermetic seal. The convolutions provide flexibility for movement while the metal construction ensures vacuum integrity and electrical isolation between contacts. It allows the moving contact to travel while preventing atmospheric gases from entering the vacuum chamber.

Materials

Stainless Steel 316L (UNS S31603) or Inconel 625 (UNS N06625) with thickness 0.1-0.3mm. Material must have high fatigue strength, excellent corrosion resistance, and low outgassing properties for vacuum applications. Electropolished finish with Ra ≤ 0.4μm to minimize particle generation.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Leak Rate	≤ 1×10⁻¹¹ Pa·m³/s
Life Cycles	≥ 30,000 operations
Spring Rate	10-50 N/mm
Vacuum Level	≤ 1×10⁻⁴ Pa
Stroke Length	8-20mm
Operating Voltage	12-40kV
Maximum Compression	30% of free length
Operating Temperature	-40°C to +105°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 8573-1, DIN 28400, IEC 62271-100, ASTM F316

Parent Products

This component is used in the following industrial products

Medium Voltage Vacuum Interrupter Module

Core vacuum switching component for medium voltage circuit breakers and contactors.

View Product Details

Engineering Analysis

Risks & Mitigation

Fatigue failure from repeated flexing
Weld joint leakage
Material contamination affecting vacuum
Over-compression leading to permanent deformation
Electrical breakdown due to insufficient clearance

FMEA Triads

Trigger: Material fatigue from excessive cycling
Failure: Bellows rupture leading to vacuum loss
Mitigation: Implement stroke limiters, use high-cycle fatigue materials, conduct regular maintenance inspections

Trigger: Improper welding during manufacturing
Failure: Leak paths developing at weld joints
Mitigation: Use automated orbital welding with helium leak testing, implement weld procedure qualifications

Trigger: Contamination during assembly
Failure: Increased outgassing and reduced vacuum quality
Mitigation: Clean room assembly, proper handling procedures, vacuum baking before sealing

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

±0.1mm on critical dimensions, ±5% on spring rate, zero visible defects on electropolished surfaces

Test Method

Helium mass spectrometry leak testing per ISO 15848, high-potential testing at 2× rated voltage, stroke cycle testing with position monitoring, thermal cycling from -40°C to +105°C

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 Metal Bellows

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.

Hebei Xinqi Pipeline Equipment Co., Ltd.

Hebei, CN

Also makes: Branch Outlet

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

View profile Send enquiry

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

Related Components

Terminal Base

A terminal base is an insulating support structure that holds and organizes electrical terminals in motor terminal blocks, providing secure connections and circuit management.

Contact Plate

A conductive plate in motor terminal blocks that establishes electrical contact between conductors.

Marking Strip

A durable marking strip used for terminal identification in motor terminal blocks to ensure proper electrical connections and safety compliance.

Gland Body

A gland body is the main housing component of an aluminum cable gland that provides mechanical protection and environmental sealing for electrical cables entering enclosures.

Frequently Asked Questions

What is the primary function of metal bellows in vacuum interrupters?

The metal bellows provides hermetic sealing between moving and stationary parts while allowing controlled axial movement of contacts, maintaining vacuum integrity and electrical insulation throughout circuit breaker operations.

Why are specific materials like stainless steel 316L used for bellows?

Stainless steel 316L offers excellent corrosion resistance, high fatigue strength for repeated flexing, low outgassing properties crucial for maintaining vacuum, and compatibility with electropolishing for clean surface finish.

How does bellows design affect vacuum interrupter performance?

Proper bellows design ensures reliable sealing throughout the operational stroke, minimizes mechanical stress on welds, provides consistent spring characteristics for contact movement, and maintains electrical clearance under all operating conditions.

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.

Metal Bellows