Graphite Products

Meaning about CHETRATHERM-graphite seals:

  • Core Quality NQ for use in nuclear power plants with CI <10 F557 and the carbon content> 99.8%.
  • Meaning BAM for use in oxygen systems up to 200 ? C and 250 bar.
  • Licence for use in the food industry.

Pure graphite seal has expanded due to the high compressibility of the graphite layer - up to 50% and that for the ongoing re-suspension of 10 to 15%. Properties of the sealants are therefore an alternating stress and excellent dynamic deployment on it almost not demonstrate fatigue. The starting material for these seals is natural graphite from which the insertion of HSO 4 groups formed graphite salts. By operating the thermal shocks graphite salts decompose back into graphite having a purity of carbon from 98 to 99.9%, making possible the expansion of the hexagonal graphite layers.


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Types of pure graphite seals:

  • Gland seals and rings for pumps and valves
  • Shaped Rings - replace O-ring
  • Flat gasket without/with stainless sheet steel
  • Sealing systems for ball valves
  • CHETRAFLEX spiral flat gasket
  • Sealing sheet and strip

Gland seals and rings are highly valuable alternative to braided packings for valves from PN10 to PN400. Rings are for specific operating pressure pre-pressed in a certain density and ensure long life (often life fittings). It is advisable to use at the pumps for hot water, heat transfer oils, acids, alkalis and solvents. They can be used also for the fans and for the safety seal.

Limit data:

Temperature: -200C to +550C
Chemical durability of pH: 0 to 14
Pressure: max. 1000 bar

Technical data:

Nominal pressure Type of seal Density (g/cm3)
Jt < 16 bar type 30V2 1,2
Jt < 40 bar type 30V3 1,3
Jt < 160 bar type 30V4 1,4
Jt < 250 bar type 30V5 1,5
Jt < 320 bar type 30V6 1,6
Jt < 400 bar type 30V7 1,7

This type of seal is preferably deployed in steam valves, fittings at high temperature and high pressure, in conventional and nuclear power plants, petrochemical and other demanding operations.

Shaped rings are their characteristics (excellent density gauge, small contact force, resistance to high temperatures and pressures) predetermined for static sealant - replace O-rings.

Flat gaskets are asbestos-free alternative to the so-called It-seal for universal use. They are mainly used for flanges to DIN / ANSI / API and searches for similar flange connections in fittings, in tanks, in heat exchangers, with a stirrer, in mixers and etc. Compared to It-seal is characterized by high compressibility - up to 50%, small deformation forces and particularly good conformability, even in rough machined surfaces.
One of the most common causes of failure It-seal is "Dismounting" under load, press and at temperature load. Small Dismounting is a condition for sealing joints, which is not additionally tighten.

Types of flat gaskets CHETRATHERM:

  • 10F0 - without the support plate
  • 10F1 - with surface impregration
  • 10F2 - with smooth support plates 0,05mm (CrNiMo 1.4401)
  • 10F3 - the needle speckled sheet 0,1mm (CrNiMo 1.4401)
  • 10F4 - with smooth support plates 1mm (1.4541 alebo 1.4571) with double-sided 0.5 mm graphite coating

Seals with impregnationor support plates are used in cases where the growing danger bruised - handling is then considerably easier.
Type 10F4 is recommended for high density gas, or when it is needed more graphite coating for corrugated flange surfaces (eg. Enamelled flanges).

Sealing systems CHETRA used to deal with problems which occur mainly in the ball valve in the high temperature and heat-resistant versions.

CHETRAFLEX spiral gasket is intended for pipe flanges under high temperature and pressure and for other flange connections according to DIN / ANSI / API as well as other special dimensions. They are robust seal of pure graphite spiral wound metal tape. Profiled metal tape enhances flexibility and sustained suspension of pure graphite CHETRATHERM. Excellent elastic properties even when constantly changing temperature and pressure loads provide many years of trouble-free operation. Void tightening screws with flanges, valves and other age flange connections - even after prolonged equipment downtime.

Technical data:

Temperature: -200C a +550C
+700C for vapor
Chemical durability of pH: 0 a 14
Fire resistance: +1000C (fire safe)

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Chetra SK, Ltd. January 2015  

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