Ring Gasket

What is a ring gasket?

Ring gaskets do not have screw holes. These gaskets are placed inside the flange bolts and around the pipe opening. Ring seals are typically used on flanges with a raised sealing surface. When used on a flange with a raised sealing surface, the o-ring seal will sit on the raised surface of the flange. An advantage of ring joints is that they can be assembled without having to completely disassemble the joint. Ring seals use less material and, since they have no bolt holes, require fewer cuts to manufacture.

When ordering ring gaskets, suppliers require these measurements:

• the ID (inside diameter), which is the inside diameter of the pipe
• the OD (outside diameter), which is the outside diameter of the raised flange face and the thickness of the plate.
• The desired pressure tolerance of the connection must also be specified.

What is a full face seal?

A full face gasket covers the entire face of the flange. Full face gaskets are typically used on flat flanges. Full-face gaskets are cut with bolt holes that allow the flange bolts to be inserted through the gasket. When installing full-face seals, the seal must be completely dismantled. When ordering full face gaskets, ID and OD must be specified along with bolt circle diameter and number and spacing of bolt holes. The thickness of the gasket and the desired
pressure tolerance of the gasket must also be specified.

Non-metallic Gasket

The most common materials used for this type of gasket are graphite, rubber, Teflon, PTFE and Compressed Non-Asbestos Fibers (CNAF). These joints are also known as soft joints. Can be full face or inner circle type

• Non-metallic gaskets can be easily compressed with low voltage bolts
• These types of gaskets are used with low-pressure class flanges, such as class 150 and 300, and also at low temperatures. However, the graphite seal can be used up to 500 degrees Celsius.
• Rubber and elastomeric gaskets are not used in hydrocarbon lines but are used in utility lines.
• Non-metallic gaskets are the cheapest and most readily available

Important properties that any gasket must possess

• Stress relaxation (yield strength): The gasket must not exhibit significant creep (creep) under load and temperature. Such flow allows the bolts to relax, reducing stress on the joint surface and causing leakage.
• Impermeability - The joint must not be porous to the liquid to be sealed.
• Elasticity: Although normally stable, the flanges move slightly relative to each other under the influence of temperature and pressure cycles. The board must be able to compensate for such movements.
• Compressibility - The gasket must be compressed into the asperities of the flange facings to create the initial seal.
• Temperature Resistance: The seal must be able to withstand the effects of maximum and minimum temperatures within the process and external atmospheric temperatures.