The sealing principle of spiral wound gaskets is revealed: How does the V-shaped metal belt achieve the spring effect?

1. V-shaped metal belt: a precisely designed elastic engine

Structural features

Geometric parameters: The typical V-shaped angle is 90°±5°, and the belt thickness is 0.15-0.25mm

Wave design: The peak-to-valley height difference is 0.3-0.5mm, and each centimeter contains 8-12 wave units

Material selection: 304/316 stainless steel accounts for 65%, and nickel-based alloys account for 30% of the high-end market

Spring action mechanism

When the flange bolt applies axial pressure:

Initial compression stage (pressure 5-15MPa):

The V-shaped wave crest first undergoes elastic deformation

The height of the metal belt is reduced by 30-40%, storing elastic potential energy

Working state:

Continuous pressure allows the filling material (graphite/PTFE) to fully fill the microscopic gaps

The metal belt maintains about 60% deformation, forming a continuous rebound force

Compensation stage:

When the flange surface produces a displacement of 0.1-0.3mm due to thermal expansion and contraction

The stored elastic potential energy is released to maintain the sealing pressure ≥50MPa

Laboratory data: After 1000 thermal cycles (-50~400℃), high-quality spiral wound gaskets can still maintain more than 85% of the initial sealing force.

2. Collaborative operations of multi-stage sealing systems

The golden combination of metal belts and fillers

Three lines of defense for dynamic sealing

• Metal belt contact seal: blocking macro leakage channels
• Seal between packing layers: nano-scale pores prevent molecular penetration
• Flange-gasket interface seal: surface roughness matching to achieve micron-level sealing

3.Analysis of the six core advantages and characteristics of spiral wound gaskets

Dynamic sealing adaptability

V-shaped metal belt spring effect: continuous rebound force is generated when under pressure (elastic recovery rate ≥ 85%)

Multi-layer sealing barrier: metal belt and filler form 3 layers of synergistic sealing (macro/meso/micro) Advantages: Automatic compensation of flange thermal deformation (0.1-0.5mm displacement), maintaining sealing stability under pressure fluctuation conditions (such as pump valve start-stop impact)

Measured data: After 100 temperature cycles (-50~400℃), it can still maintain 90% of the initial sealing force.

Tolerance to extreme working conditions

Metal belt temperature resistance limit: 316L stainless steel up to 800℃, nickel-based alloy up to 1100℃

Packing medium resistance design: graphite resistant to strong acid, PTFE resistant to strong alkali, mica resistant to radiation Advantages: Covering the full temperature range from -196℃ to 1100℃ (covering LNG to oil refining scenarios), resistant to chemical corrosion with pH value of 0-14 (such as 98% sulfuric acid pipeline)

Customizable structure

Parameterized adjustment: Adjust the elastic modulus by changing the number of metal belt layers (4-16 layers)

Reinforcement ring selection: The inner ring enhances the anti-blowout ability, and the outer ring is precisely positioned Advantages: Adapt to various flange standards such as ASME/EN/DIN, optimized for low bolt load conditions (specific pressure can be as low as 30MPa)

Safety and reliability

Metal skeleton anti-creep: cold-rolled stainless steel belt yield strength ≥205MPa

Failure warning mechanism: Leakage passes through the packing layer first to avoid sudden failure Advantages: Pass API 6A/ASME B16.20 and other stringent certifications, 10 years of maintenance-free high-pressure pipelines in refineries

Economic advantages

Long-life design: typical service life 8-10 years (asbestos gaskets only 1-2 years)

Low maintenance cost: replacement frequency reduced by 80% Advantages: comprehensive cost is 40% lower than metal ring gaskets, and downtime maintenance time is shortened by 70%

Environmental compliance

Asbestos-free design: compliant with EU REACH regulations

Recyclable materials: metal belt recycling rate ＞95% Advantages: Passed ISO 14001 environmental management system certification, meets the requirements of zero release of radioactive substances in nuclear power plants