The sealing gasket is the essential element for any pressurized system. It has many benefits for operating an industrial plant, safely and efficiently. The sealing gasket provides a cushion element between two metallic mating surfaces in the pressure system. This cushion element between the two metallic surfaces prevents leakage and loss of fluid through the joint. In industries and household set-ups, there are various equipment flange joints. Equipment joints must be sealed with gaskets, to prevent the leakage of fluids through them. Gasket sealing is mainly two types.
(1) STATIC SEALING
Static gasket sealing is used to prevent the loss of fluids through pressure vessels and pressure piping. Apart from pressure vessels and pressure piping, it is used in almost every piece of industrial equipment. A domestic appliance like a pressure cooker and mixer grinder also will not be able to function without gasket sealing.
(2) DYNAMIC SEALING
Dynamic sealing is used to prevent the loss of fluids in the sliding or rotating motion of the equipment shaft. They are used in pumps, compressors, and all other rotary and reciprocating equipment.
LIST OF GASKET MATERIALS
(1) Gum rubber sheet.
(2) Hard rubber sheet.
(3) Cloth inserted soft rubber.
(4) Cloth inserted vulcanite.
(5) Vegetable fiber sheet (Hemp or Jute).
(6) Rubberized woven wire inserted asbestos (1 ply,2ply,3ply).
(7) Compressed asbestos.
(8) Spiral wound asbestos-filled.
(9) Corrugated metal asbestos inserted.
(10) Corrugated metal jacket asbestos-filled.
(11) Corrugated Metal.
(12) Flat metal jacket asbestos-filled.
(13) Grooved iron or soft steel core metal jacketed.
(14) Solid metal thinner gasket.
SELECTION OF GASKET
The following parameters to be taken into account for roper selection of material and type of gasket
(1) The internal pressure of the piping system.
(2) The temperature of the process fluid.
(3) Properties of the process fluid.
(4) Compressive load of bolts or studs.
(5) The ring-type gasket is suitable for raised face flanges.
(6) The full gasket is suitable for flat flanges.
Gasket material to be suitable for:
(1) Gasket material to be able to sustain pressure and temperature.
(2) Gasket dimensions to be suitable to accommodate the flanges.
(3) Gasket material should withstand the compressive load of bolts without tearing or distortion.
ADVANTAGES OF PROPER GASKET SEALING
(1) Prevent the loss of precious fluid through the flange joint.
(2) Prevent pollution in the atmosphere due to leakage of toxic fluid through the flange joint.
(3) Prevent fire hazards due to the leakage of flammable liquids through the flange joint.
(4) Prevent shut down of equipment due to leakage through flange joint.
(5) Prevent Downtime and production loss in the plant due to leakage.
PROPER INSTALLATION OF GASKET
The following things to be ensured, before starting the installation of the gasket.
(1) Cleanliness and condition of the tools being used for gasket installation.
(2) Torque wrench must be calibrated, which’s being used for bolt tightening.
(3) Appropriate bolt tensioner to be used.
(4) Hardened washer to be used.
(5) Brass wire brush to be used for cleaning of flange surfaces and cleaning of bolts or studs.
(6) Clean the flange faces and gasket sealing area of the flange to make sure that it’s free from any foreign matter and freed from scratches on seating.
(7) Make sure that the flanges are parallel to each other and there’s no misalignment either offset or angular. Ensure that the bolts or studs can pass easily through flange holes.
(8) Before entering the gasket between the flanges, make sure that the gasket is of correct dimensions, material, and type. This is often essential to verify to get the optimum life of the gasket.
(9) Before tightening the flanges make sure that the gasket isn’t being pinched between the flanges.