Introduction to Spiral Wound Gaskets
Spiral wound gaskets are sealing elements formed by alternately winding metal strips and non-metallic filler materials. They combine the strength of metal with the sealing properties of non-metallic materials, making them widely used sealing components in industrial pipelines and equipment.
Core Characteristics
| Characteristic |
Description |
Advantages |
| Excellent Sealing Performance |
The combination of metal and non-metallic materials provides multiple sealing barriers. |
Suitable for high-pressure and high-temperature conditions. |
| Good Elastic Compensation |
The unique wound structure allows for certain compression and rebound. |
Adapts to uneven flange surfaces. |
| High Temperature and Pressure Resistance |
Can withstand temperatures up to 800°C and pressures up to 25 MPa. |
Can withstand temperatures up to 800°C and pressures up to 25 MPa. |
| Resistance to Creep and Relaxation |
Metal strips provide mechanical strength and resist sustained loads. |
Maintains long-term sealing stability. |
| Multiple Material Combinations |
Different metals and filler materials can be selected based on the medium. |
Adapts to various corrosive environments. |
Basic Structure
| Component |
Material Options |
Function |
| Metal Strip |
304/316 stainless steel, Inconel, titanium alloy, etc. |
Provides mechanical strength and elasticity. |
| Filler Material Graphite, |
Graphite, PTFE, ceramic fiber, etc. |
Provides primary sealing function. |
| Inner and Outer Rings |
Usually made of the same material as the metal strip. |
Positioning and reinforcement. |
Type Classification
| Type |
Structural Features |
Applicable Standards |
Applications |
| Basic Type |
No inner or outer rings |
ASME B16.20 |
Tongue-and-groove flange faces. |
| Inner Ring Type |
With inner ring |
EN 1092-1 |
Raised face flanges. |
| Outer Ring Type |
With outer ring |
DIN 2696 |
Flat face flanges. |
| Inner and Outer Ring Type |
With both inner and outer rings |
JB/T 90 |
High-pressure applications. |
Performance Parameters Table
| Performance Indicator |
Graphite Filler |
PTFE Filler |
Ceramic Fiber |
Filler Test Standard |
| Operating Temperature (°C) |
-200~800 |
-200~260 |
-200~1100 |
ASTM F38 |
| Operating Pressure (MPa) |
≤25 |
≤10 |
≤20 |
ASME B16.20 |
| Compression Rate (%) |
18~30 |
15~25 |
20~35 |
ASTM F36 |
| Recovery Rate (%) |
≥17 |
≥15 |
≥20 |
ASTM F36 |
| Stress Relaxation Rate (%) |
≤15 |
≤20 |
≤18 |
ASTM F38 |
Selection Guide
1. Material Selection Principles:
· The metal strip material should be equal to or better than the flange material.
· The filler material must be compatible with the process medium.
· Consider temperature and pressure fluctuations.
2. Size Determination:
· Determine gasket size based on flange standards.
· Consider bolt load and flange stiffness.
· Reserve appropriate compression space.
3. Special Condition Considerations:
· Use more elastic materials for thermal cycling conditions.
· Use advanced alloy materials for corrosive environments.
· Special treatment is required for ultra-high vacuum environments.
Installation and Usage Requirements
1. Pre-Installation Inspection:
· Flange sealing surfaces should be clean and undamaged.
· Confirm the correct gasket model and material.
· Check if the gasket is intact and undamaged.
2. Installation Specifications:
· Use positioning tools to ensure alignment.
· Tighten bolts gradually in a diagonal sequence.
· Achieve the specified bolt preload.
3. Maintenance Recommendations:
· Regularly check bolt tightness.
· Re-tighten after thermal cycling.
· Inspect gasket compression status during shutdown.
Application Fields
1. Petrochemical Industry: Reactors, heat exchangers, pipeline flanges.
2. Power Industry: Steam turbines, boiler systems.
3. Refining Units: Hydrocracking, catalytic cracking units.
4. Nuclear Power Industry: Nuclear-grade equipment sealing.
5. Aerospace: Engine pipeline systems.
Spiral wound gaskets, with their unique structure and excellent sealing performance, are the preferred sealing elements for high-temperature and high-pressure conditions. Through reasonable material selection and correct installation, they can provide reliable long-term sealing for various industrial equipment. Their flexibility in multi-material combinations allows them to adapt to extreme conditions, from low-temperature cryogenic to high-temperature and high-pressure environments.
