Gasketing

HOW TO:
GASKETING


Gaskets are used to prevent leakage of fluids or gases by forming impervious barriers. For successful gasketing, it is necessary for the seal to remain intact, and leak-free over a long period of time. The gasket must be resistant to fluids and/or gases, and withstand the operating temperatures and pressures to which it is subjected.

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Gasketing Methods

Possible reasons of failure Part 1

Possible reasons of failure Part 2

Liquid gaskets and their curing methods

Gasketing: Additional Knowledge

Learn everything you need to know about the subject of gasketing.

Liquid gaskets are "formed-in-place" (FIP) gaskets = Formed by application of a liquid sealant.

Advantages of liquid gasketing products:

LOCTITE gasketing products are self-forming seals that:

• fill all voids e.g. surface roughness & imperfections

• provide total contact

• cure to a durable seal with adhesion to both flange surfaces

• eliminate flange face corrosion

• offer an excellent instant seal

 

Gasketing to prevent leakages - LOCTITE anaerobic sealants are self-forming seals.

Anaerobic sealant

Elastomeric sealant (silicone)

Over time, compression gaskets relax under dynamic loads and decrease in thickness, with subsequent loss of bolt tension in the flange joint resulting in leakage.

Uneven and localised stresses can also occure as a result of assembly with conventional gaskets.

Gasketing to prevent leakages - Gasket relaxation and creep.

Compression gaskets have only limited potential to accommodate irregularities. For example: machining marks, scored surfaces, flatness tolerances, etc.

Over time, the compression load on the gasket can cause a decrease in the thickness of the gasket and/or loss of resilience.

Gasketing to prevent leakages - Compression gaskets have limited potential to accommodate irregularities.

A squeezing-out out of the compression gasket can be caused by a combination of low compression load and vibration or high internal pressure (p1>p0).

Gasketing to prevent leakages - Squeezing-out of compression gasket.

Bolt tension in combination with a compression gasket tends to create flange bowing, albeit to varying degrees, depending on the bolt intervals. Bowing is mainly observed in flexible flanges (metal sheet covers).

Bowing results in low compression or even a gap opening mid-way between two bolts.

Gasketing to prevent leakages - Bolt tension tends to create flange bowing.

Differential thermal expansion of flanges made from different materials increases flange bowing.

Deformation results in gap formation and leakage.

Gasketing to prevent leakages - Deformation results in gap formation and leakage.

a) Stays liquid in contact with oxygen


b) Cures to a solid thermoset plastic in the absence of air whilst in contact with a metal surface

Gasketing to prevent leakages - How a LOCTITE anaerobic gasket cures.

LOCTITE silicones cure with atmospheric moisture releaseing by-products while forming a flexible elastomer.

Gasketing to prevent leakages - How a LOCTITE silicone gasket cures.