Metal gasket of ammonia valve - graphite gasket of liquid ammonia valve - spiral wound gasket
Introduction to Spiral Wound Gaskets:
The metal gasket of ammonia valve is formed by alternating winding of V-shaped or W-shaped thin steel strip and flexible graphite, which can withstand high temperature and high pressure and adapt to use under ultra-low temperature or vacuum conditions. The spiral wound gasket is equipped with metal inner reinforcing ring and outer locating ring, and its greater compression degree is controlled by using inner and outer steel rings. The spiral wound gasket is especially suitable for occasions where the load is uneven, the connection force is easy to relax, the temperature and pressure change periodically, and there is impact or vibration. Spiral wound gaskets are ideal static sealing components for flange connections of valves, pumps, heat exchangers, towers, manholes, handholes, etc.
Type of spiral wound gasket:
1. Basic metal wound gasket
2. Metal wound gasket with outer ring
3. Metal wound gasket with inner ring
4. Metal wound gasket with inner and outer rings
Graphite gasket gasket of liquid ammonia valve:
1. Confirm that the gasket conforms to the specified size and material;
2. Check the gasket to ensure there is no defect;
3. Carefully insert sealing gasket between two flanges;
4. Confirm that the gasket is in the central position between flanges;
5. Unless the gasket installation instructions require the use of adhesive or anti adhesive, it shall not be used privately;
6. Align the flange face to ensure that the gasket is not punctured or scratched.
The metal spiral wound gasket (basic type) is made of high quality SUS304, SUS316 ("V" or "W" shape) metal belt and other alloy materials and soft materials such as chrysotile asbestos, flexible graphite, polytetrafluoroethylene, non asbestos fiber [1] by overlapping and spiral winding, and the metal belt is fixed by spot welding at the beginning and end.
Precautions for use of graphite gasket of liquid ammonia valve:
1. The winding part of the gasket must be between the flange sealing surfaces, and the width of the winding part cannot be widened at will, which will inevitably affect the compression force of the bolt, thus affecting the sealing performance of the gasket.
2. It is better not to use the basic type gasket on the concave and convex face flange, because under the axial compression force of the flange, the welding point of the inner ring of the gasket is easy to open, leading to gasket failure.
3. Under severe working conditions such as high temperature, cold or frequent alternation of cold and hot, large vibration, strong corrosive media, gaskets used for flat flanges and raised flanges should be equipped with inner rings of reasonable materials.
