Definition and Types of Flange Sealing Gaskets
Flange Sealing Gaskets
1. What is a flange sealing gasket?
The rubber pads used between industrial bearings for shock absorption and wear resistance are called flanges. The flange sealing gasket used in industry is a key part of preventing leakage. Commonly used gaskets are PTFE gaskets, metal gaskets, inner and outer ring metal gaskets, graphene gaskets, rubber sealing gaskets, etc.
2. Types of flange sealing gaskets
1) PTFE gaskets
It is made of PTFE material. PTFE gaskets are mainly suitable for FF (full face) and RF (raised face) steel flange connections.
2) Metal wound gaskets
It is a semi-metallic flat gasket made by combining a metal outer ring with graphene. The characteristic of metal wound gaskets is good compression and rebound performance, with multiple sealing and certain self-tightening functions. They can maintain their excellent sealing performance under various harsh conditions such as high temperature, low pressure, high vacuum, impact vibration, and other cyclic changes. There are four types of metal wound gaskets: basic type, inner ring type, locating ring type, inner ring type, and locating ring type.
3) Metal-wrapped shoe gaskets
It is a composite gasket made of non-metallic materials as the core material, cut into the desired shape, and surrounded by a metal sheet with a thickness of 0.25 to 0.5mm. According to the status of the shoes, they are generally divided into two types: flat and corrugated. It can be divided into two types according to structural type: flat type (F-type) and corrugated type (C-type). The structural type of metal-clad gasket used for pressure vessel flanges is flat.
4) Graphite composite gaskets
Known as a flexible graphite composite gasket, it is usually cut from a graphite composite reinforcement plate. The main characteristics of graphite composite gaskets are good resistance to high temperature, low temperature, corrosion, radiation, and other properties. They have high strength and can be used under high-pressure conditions. The types of flexible graphite composite gaskets are divided into RF type, MFM type, and TG type, which are respectively suitable for raised face, concave-convex face, and tenon groove face flanges.
5) Metal wave tooth composite gaskets
This type of gasket has both the strength of metal and the characteristic of corrugated elasticity, with a maximum temperature of 650 degrees and a maximum pressure of up to 26MPa. Flexible graphite metal wave tooth composite gaskets can be divided into three types according to their different structures.
6) Metal ring sealing gaskets
It is a solid metal gasket made of stainless steel or alloy material with an octagonal or elliptical cross-section, which has a radial self-tightening sealing effect. The metal ring sealing gasket is matched with the flange groove, which has good sealing performance, but it requires high machining accuracy. Therefore, the manufacturing is relatively high.
7) Octagonal and elliptical pads
The octagonal gasket and elliptical gasket (commonly known as "earth steel ring" in the refining industry) used for trapezoidal groove flanges have good sealing performance. On the conical surface of the groove, the octagonal pad is in surface contact while the elliptical pad is in line contact. Therefore, the elliptical pad has good adhesion under low tightening force but requires secondary tightening. However, octagonal gaskets are generally less prone to leakage after being tightened at once.
1. What is a flange sealing gasket?
The rubber pads used between industrial bearings for shock absorption and wear resistance are called flanges. The flange sealing gasket used in industry is a key part of preventing leakage. Commonly used gaskets are PTFE gaskets, metal gaskets, inner and outer ring metal gaskets, graphene gaskets, rubber sealing gaskets, etc.
2. Types of flange sealing gaskets
1) PTFE gaskets
It is made of PTFE material. PTFE gaskets are mainly suitable for FF (full face) and RF (raised face) steel flange connections.
2) Metal wound gaskets
It is a semi-metallic flat gasket made by combining a metal outer ring with graphene. The characteristic of metal wound gaskets is good compression and rebound performance, with multiple sealing and certain self-tightening functions. They can maintain their excellent sealing performance under various harsh conditions such as high temperature, low pressure, high vacuum, impact vibration, and other cyclic changes. There are four types of metal wound gaskets: basic type, inner ring type, locating ring type, inner ring type, and locating ring type.
3) Metal-wrapped shoe gaskets
It is a composite gasket made of non-metallic materials as the core material, cut into the desired shape, and surrounded by a metal sheet with a thickness of 0.25 to 0.5mm. According to the status of the shoes, they are generally divided into two types: flat and corrugated. It can be divided into two types according to structural type: flat type (F-type) and corrugated type (C-type). The structural type of metal-clad gasket used for pressure vessel flanges is flat.
4) Graphite composite gaskets
Known as a flexible graphite composite gasket, it is usually cut from a graphite composite reinforcement plate. The main characteristics of graphite composite gaskets are good resistance to high temperature, low temperature, corrosion, radiation, and other properties. They have high strength and can be used under high-pressure conditions. The types of flexible graphite composite gaskets are divided into RF type, MFM type, and TG type, which are respectively suitable for raised face, concave-convex face, and tenon groove face flanges.
5) Metal wave tooth composite gaskets
This type of gasket has both the strength of metal and the characteristic of corrugated elasticity, with a maximum temperature of 650 degrees and a maximum pressure of up to 26MPa. Flexible graphite metal wave tooth composite gaskets can be divided into three types according to their different structures.
6) Metal ring sealing gaskets
It is a solid metal gasket made of stainless steel or alloy material with an octagonal or elliptical cross-section, which has a radial self-tightening sealing effect. The metal ring sealing gasket is matched with the flange groove, which has good sealing performance, but it requires high machining accuracy. Therefore, the manufacturing is relatively high.
7) Octagonal and elliptical pads
The octagonal gasket and elliptical gasket (commonly known as "earth steel ring" in the refining industry) used for trapezoidal groove flanges have good sealing performance. On the conical surface of the groove, the octagonal pad is in surface contact while the elliptical pad is in line contact. Therefore, the elliptical pad has good adhesion under low tightening force but requires secondary tightening. However, octagonal gaskets are generally less prone to leakage after being tightened at once.
