1. The basic metal winding gasket: 

It is made of the overlapped spiral wound high -quality SUS304, SUS316 (" V "or" W "shape) stainless steel wrapping belt coil and soft materials of graphite, asbestos, PTFE, and non-asbestos etc.. At the start and the end, the metal belt is fixed in spot welding way. The basic metal winding gasket has no inner and outer ring.  It is generally used in middle and low pressure flange with tongue groove face and plan or concave and convex. 

2. Metal winding gasket with inner ring: 

The inner ring commonly shall be the same material with the winding belt, it shall comply with corrosion-resistance requirement of pipeline medium, it is usually better than that of pipeline or flange. According to the standard requirements , the metal winding belt is fixed on the inner ring and the metal winding belt is wound with none-metal winding belt of graphite, asbestos, PTFE, non- asbestos etc. continuously, mutually overlapping and spirally winding, at the end of the metal belt  is fixed in spot welding way. The inner ring is also called reinforcement ring to avoid loosening of winding gasket ring. 

Performance characteristics: Controlled by the inner ring, the metal winding gasket with inner ring makes the gasket get maximum compaction degree, the accuracy of the flange sealing surface contacting the winding gasket is not highly required. The metal winding gasket is especially suitable for the occasion where load is not even, the jointing force is easy to lose, the  temperature and pressure  periodically changes and has impact or vibration.  It is generally used in middle and low pressure flange with tongue groove face and plan or concave and convex. 

Application equipment: It is used for the sealing of flange connections of  pipelines, valves, pressure vessels, condenser, heat exchanger, tower, manhole, hand hole in petroleum, chemical industry, metallurgy, electric power, shipbuilding and machinery industries such as pipelines, valves, pressure vessels, condenser, heat exchanger, tower, manhole and hand hole.        

3. Metal winding gasket with external ring: In the outside of the basic metal winding gasket, cover a metal outer ring, which is used for aligning of flange and gasket and controlling the gasket compression force. The outer ring is also called aligning ring, in foreign country, the outer ring generally is galvanized or coated carbon steel or is the same material with pipe or flange. 

Performance characteristics: The existing of winding outer ring facilitates aligning, therefore the flange is easily dismounted. The outer ring is used to control the maximum compaction degree, the gasket with outer ring has better compression performance and elasticity; it has multichannel sealing and a certain self-tightening function. The gasket with outer ring is not sensitive to the surface defects of the compacting surface of the flange, it can eliminate the impact from part of pressure, temperature changing and mechanical vibration. It can keep its good sealing performances at all kinds of harsh conditions of circulation and alternating changing of high temperature, low temperature, high vacuum, impact and vibration. The metal graphite winding gasket with outer ring is generally used in middle and low pressure flange with plane and  convex flange.

4. Metal winding gasket with inner and outer ring: 

It is a kind of sealing gasket that has been widely used at present, it is the gasket with best resilience in semi-metal sealing gasket, it is formed by alternately winding of V or W -type thin steel and various of filling- materials such as: graphite and PTFE. By the changing to the gasket material combination, the problem of chemical corrosion of all kinds of medium to gasket can be solved. In order to strengthen the main body and accurate positioning, the metal internal reinforcement ring and outside positioning ring form are used. The internal and outside ring is used to control the maximum compaction degree and play a part of strengthening and avoiding the loosening of main body. The existing of outside ring makes the installation more convenient. 

Performance characteristics: It can resist the high temperature, high pressure and can adapt the super low temperature or vacuum conditions, the surface of the flange sealing surface contacting with the gasket is not highly required and can be dismantled conveniently.