Gaskets for leak Proof Flanged joints

A gasket is a soft sealing material closed between two flanges in order to make a leak-free sealing application. For proper functioning and cost-effectiveness of flanged joints:-

  • Flanges must be enormous stiff and massive.
  • Flange faces should be super smooth.
  • Flanges should be closed without tension on the pipes
  • Flanges should be 100% parallel.

But the above is economically not feasible.

Functions of a Gasket

Hence the solution is to use relatively light and cheap flanges in combination with the correct finish in combination with compressible soft GASKET. So the main functions of a GASKET are:

  • The gasket material has to fill the uneven surface of the flange in order to prevent leakage between the gasket and the flange surface.
  • The gasket material has to overcome the misalignment of the flanges in order to prevent leakage between the gasket and the flange surface.
  • Leakage through the gasket has to be reduced to the minimum against internal pressure-Emission
How Gasket Works?
How Gasket Works?

Characteristics of a Gasket

  • The gasket material has to be soft in order to compress this in the irregularities of flanges.
  • The gasket should be Gas-Liquid tight so that it does not leak or cause emission.
  • The gaskets should not creep under influence from stress and temperature. This could result in lower bolt stresses and possible leakage.
  • The resilience of the gasket should take static and dynamic effects due to stress, temperature, and pressure.
  • The gasket has to withstand internal pressure without being blown out.
  • The gasket should be capable to achieve sealing at elevated temperatures.
  • It has to be resistant to the chemical attack of the medium without polluting the media.
  • It should possess anti-stick properties such that when opening the flange, the gasket has to loose easily from the flange.
  • It has to be stiff enough to make installation as easy as possible.

Gasket Selection

  • Flange Construction- The thickness of the flange has an effect on the bolt load and therefore seating stress. Thin and deformed flanges need softer gaskets.
  • Standardization-
  • Quality Studbolts-
  • Emission Parameters- Each selected gasket has different emission parameters.
  • Flange Misalignment- Maximum misalignment of flanges will be 0.4 mm.

Why do Gaskets Leak?

  • Damage during assembly
  • Poor Gasket selection
  • Excessive flange rotation
  • Gasket damage or relaxation due to flange rotation
  • Gasket damage due to differential thermal expansion
  • Incorrect assembly bolt load
  • Load loss due to thermal fluctuation
  • Gasket load loss due to pressure and or piping loads
  • excessive gasket relaxation
  • Excessive gasket load

What costs are involved with a Gasket failure?

  • Low profit due to leakage
  • Cost of online sealing with clamps
  • Cost of re-matching
  • Cost of replacement equipment
  • Cost of Engineering and maintenance hours spent addressing leakage
  • Report of incidents and additional paperwork
  • Pollution of environment
  • Cleaning costs
  • Possible personal injuries
  • Cost of disassembly, repair and machining

What could engineering do to prevent leakage through Gaskets?

  • Proper selection of the correct assembly bolt stress
  • Correct location, constraint and width of the sealing
  • Consideration of bending loads, misalignment.
  • Quantify effects of gasket creep/relaxation
  • Quantify effects of temperature and pressure
  • Maximum permissible assembly load
  • Correct gasket selection
  • Root cause analysis

Basic calculations for Gasket Selection

Gasket Materials

  • Rubber gasket
  • Fibre Sheet Gaskets (Asbestos, Aramide, Acrylic, Carbon, Ceramic, Rockwool, Glass fibers, Carbon fibers, Graphite)
  • PTFE Gaskets
  • Graphite Gaskets
  • Spiral Wound Gaskets
  • Cam profile Gaskets
  • Flat Metal Reinforced Gaskets
  • Ring Type Joints
  • Insulating Kits
  • Metallic Gaskets
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Anup Kumar Dey

I am a Mechanical Engineer turned into a Piping Engineer. Currently, I work in a reputed MNC as a Senior Piping Stress Engineer. I am very much passionate about blogging and always tried to do unique things. This website is my first venture into the world of blogging with the aim of connecting with other piping engineers around the world.

One thought on “Gaskets for leak Proof Flanged joints

  1. I want to know more about different types of flexible pipe and how to get their measurements,also their fittings

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