Product category:
Seals
News Release from: Freudenberg Simrit LP | Subject: KTW-approved composite seals
Edited by the Engineeringtalk Editorial
Team on 17 April 2008
Composite seals are approved for
drinking water
Approval for coated O-ring rules out the possibility of drinking water contamination caused by cleavage products that may occur during the coating process.
For the first time ever a composite seal comprising an O-ring and a coating has received KTW approval for use with drinking water The approval rules out the possibility of drinking water contamination caused by cleavage products that may occur during the coating process
This article was originally published on Engineeringtalk on 18 Feb 2003 at 8.00am (UK)
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Simrit is the very first O-ring manufacturer to have two of its ISC materials (70 EPDM 281 and 70 NBR 150) and the coating SCB 009.01 in the form of a composite O-ring plus coating tested and approved for hot water applications (up to 85C) in accordance with KTW by the TZW testing institute in Karlsruhe, Germany.
Both these materials and the coating already had the appropriate respective KTW approvals as independent components.
Applying special coatings to O-rings makes them easier to install.
Coatings also help bring about a targeted reduction in insertion forces, which is particularly important for quick-fitting pipe unions and press fit systems.
However, it is not enough for these coatings to reduce friction; they must also prove their compatibility for use with drinking water by meeting statutory requirements.
Even though both the O-ring material and the coating have to comply with separate drinking water approval requirements, this alone is not enough to make them suitable for use in drinking water applications.
The only way to ensure that an O-ring and coating meet the tough requirements of drinking water approvals and to exclude any possible contamination of the drinking water by cleavage products that may occur during the coating process is to subject the composite part to a test.
Moreover, it is important that the approval tests are conducted in hot water (up to 85C) because it is only under extreme conditions such as these that the suitability of the coating for a drinking water system can effectively be tested.
The advantage for users is that they can use this composite system of O-ring and coating immediately: there is no need to worry about compatibility, and no lengthy and costly testing formalities.
The KTW approval completely excludes the possibility of any unwanted interaction between the O-ring/coating and the drinking water.
Naturally, these advantages also apply to hot water applications.
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