Seal/Weld: Leak Rate <1×10⁻⁹ mbar·L/s (helium)

Q: What is the difference between seals and welds in pressure sensing elements?

Seals are removable interfaces using compression of materials like elastomers or metals to prevent leakage, allowing for maintenance and component replacement. Welds are permanent fusion joints that provide superior strength and hermeticity but require cutting for disassembly. Selection depends on application requirements for pressure, temperature, maintenance frequency, and cost.

Q: How do I select the right material for seal/weld components?

Material selection depends on the operating environment: consider media compatibility (chemical resistance), temperature range, pressure requirements, and regulatory standards. Common choices include stainless steel for welds in corrosive environments, FKM elastomers for high-temperature seals, and PTFE for chemical resistance. Always verify compatibility with industry standards like ISO or ASTM.

Component Specifications

Definition

A specialized component within pressure sensing elements that provides either a permanent welded joint or a removable seal to isolate the sensing medium from the external environment. This component maintains the integrity of the pressure chamber, prevents leakage, and protects sensitive internal elements from contamination, corrosion, or mechanical damage while ensuring accurate pressure transmission to the sensing diaphragm.

Working Principle

The seal/weld component functions by creating a barrier between the pressure medium and the sensor's internal components. Welded joints provide permanent, high-strength connections through fusion of materials, while seals use elastomeric or metallic gaskets with compression to prevent fluid or gas leakage. Both methods maintain the pressure boundary, ensuring the sensing diaphragm receives undistorted pressure signals without external interference.

Materials

Welds: Typically matching base metals (stainless steel 316L, Hastelloy, titanium) with compatible filler materials. Seals: Elastomers (FKM/Viton, EPDM, silicone), PTFE, or metallic (Inconel, copper) depending on temperature, pressure, and chemical compatibility requirements.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Leak Rate	<1×10⁻⁹ mbar·L/s (helium)
Seal Type	Static or dynamic
Weld Type	TIG, laser, or electron beam
Surface Finish	Ra ≤ 0.8 μm for sealing surfaces
Pressure Rating	Up to 10,000 psi (690 bar)
Temperature Range	-40°C to 200°C (-40°F to 392°F)

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 9001, ASME BPVC, DIN EN 1092, ASTM A240

Parent Products

This component is used in the following industrial products

Pressure Sensing Element

The core component within a pressure sensor/transmitter that directly converts applied pressure into a measurable physical change.

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Engineering Analysis

Risks & Mitigation

Leakage due to improper installation
Material degradation from chemical exposure
Thermal stress cracking
Fatigue failure from pressure cycling
Contamination ingress

FMEA Triads

Trigger: Incorrect torque application during seal installation
Failure: Seal deformation or uneven compression leading to leakage
Mitigation: Implement calibrated torque tools and training; use compression limiters; follow manufacturer specifications

Trigger: Thermal expansion mismatch between welded materials
Failure: Crack formation at weld joints under temperature cycling
Mitigation: Select materials with compatible thermal coefficients; use stress-relieving heat treatments; design with expansion joints

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Dimensional tolerances per ISO 2768-m; pressure testing to 1.5× rated pressure without leakage

Test Method

Helium leak testing per ASTM E493, pressure cycling per ISO 19879, material certification per ASTM/EN standards

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

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

Manufacturers of Seal/Weld

Manufacturer profiles associated with Seal/Weld.

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Frequently Asked Questions

What is the difference between seals and welds in pressure sensing elements?