HIGH TEMPERATURE O-RINGS

 

While considering efficient sealing in O-Rings, the range of temperate experienced during the operation is an important factor. The exposure of O-Ring elastomers to excessive high temperature can cause physical or chemical deterioration. Due to high temperature, O-Rings will initially soften and swell within the gland, causing increased friction in dynamic applications. Resistance of elastomers to chemical attack is greatly reduced by elevated temperature.

Various special compounds have been developed to provide dependable performance in high temperature. They are as follows:

Silicone O-Rings

  • Silicone O-Rings are known for excellent compression set and permeation resistance.
  • They have a temperature range of -59°C to 232°C.
  • They are mostly used in products which require dry heat, are odourless and non-toxic, and have a wide temperature range.
  • Silicone is a semi-organic elastomer with outstanding resistance to extremes of temperature with corresponding resistance to compression set and retention of flexibility.
  • Silicone elastomers provide excellent resistance to ozone, oxygen, and moisture. They, however, have poor wear resistance and short term resilience, and are not convenient for products such as acids and brake fluids, thus making more manufacturers go for rubber.
  • Silicone utilizes a flexible siloxane backbone rather than a carbon backbone like many other elastomers and has very low glass transition temperatures. Low physical strength and abrasion resistance combined with high friction properties limit silicone to static seal applications.

 

PERFLUOROELASTOMER O Ring (KALREZ/ SIMRIZ/CHEMRAZ)

Temperature ranges -10°C to 615°C

1. Kalrez

  • Kalrez possess enhanced physical properties including very low compression set and improved seal force retention.
  • It has excellent chemical resistance
  • Offers high temperature stability up to 320°C

2. Simriz

  • Typical application environment are aggressive acid, bases and solvent
  • It is used in dry, high heat below 310°C.

3. Chemraz

  • It can handle continuous operating temperature up to 310°C with outstanding resistance to fatal thermal related compression set.
  • It excels in handling dynamic applications.
  • It exhibits unparalleled performance in high temperature (steam and water)

 

FLUOROELASTOMERS O-Ring (Viton)

  • Endure thermal excursion up to 240°C.
  • It operates efficiently under high temperature.
  • Fluorocarbons are highly resistant to swelling when exposed to gasoline as well as resistant to degradation due to expose to UV light and ozone.
  • FKM materials are not generally recommended for exposure to hot water, steam, polar solvents, low molecular weight esters and ethers, glycol based brake fluids, or hot hydrofluoric or chlorosulfonic acids.
  • It well suited in resisting hardening and embrittlement
  • Viton O-Rings are commonly used by many O-Ring manufacturers, especially in acids, chemicals, silicone oils, halogenated hydrocarbons and petroleum products amongst others.

These high temperature O-Rings can prevent physical or chemical damage and retain their properties that otherwise cannot be prevented with compounds with low resistance to extreme temperatures.

 

At Ismat , we manufacture O-Rings for extreme conditions. Using our decadeds of experience we satisfy customer requirements for their varying needs.