What’s the Difference Between a Gasket and a Seal?
What Is a Gasket?
A gasket is a ring or sheet composed of a supple material used in static applications to seal joints, flanges, and other mating surfaces to prevent leakage.
Depending on the material and application, gaskets can be produced using a broad range of manufacturing techniques, including:
Rubber extrusion
Hot vulcanized and cold bond splicing
Compression, injection and transfer molding
Precision slitting
Custom die cutting
Waterjet cutting
Both gaskets and seals can be found in nearly every application and industry, including oil and gas, manufacturing and industrial applications, pulp and paper production, and agricultural equipment.
Worn or broken gaskets are easy to replace. It is typically recommended to change gaskets any time the equipment is disassembled and reassembled.
What Is a Seal?
Seals are a broader category that includes o-rings, valve stem seals, rotary seals, and mechanical seals. Unlike gaskets, which are typically used for static applications, seals are found in more active environments in motors, engines, pumps, and rotary shafts. Seals tend to be flat and round, with a tilted inner ring of rubber surrounded by a metal outer ring. The tilted angle of the seal’s inner layer helps to prevent leakage in dynamic applications. Seals are typically used to prevent leaks between two moving parts, and to prevent the intrusion of particles and contaminants into the system.
The process for replacing a broken or damaged seal can be very involved. Not only the seal, but the entire assembly may need to be dis-assembled to get access to the seal and allow for replacement.
Gasket and Seal Materials
Seals and gaskets can be made of a broad range of materials, depending on the applications for which they will be used. Common materials used to make both gaskets and seals include:
Buna ‘N’ (Nitrile)
CSR (Hypalon®)
EPDM
Flourosilicone
Fluoroelastomer (FKM)
Natural Rubber (polyisoprene)
Neoprene
Polyurethane
Silicone
Synthetic Polyisoprene
Thermoplastic Rubber (TPR)
Viton®