Product category:
Seals
News Release from: Freudenberg Simrit LP | Subject: 70 EPDM 291 O-rings
Edited by the Engineeringtalk Editorial
Team on 18 October 2004
Elastomer seals solar water panels
safely
Simrit has developed a new elastomer compound specifically for simple connections and permanent sealing of thermal solar collectors and complete solar systems.
To date the core problem of solarthermy has been the permanent sealing of liquid cycles On the one hand, solar collectors, solar heating, energy roof elements, heat pumps and also valves must remain tight for years
This article was originally published on Engineeringtalk on 7 Jul 2003 at 8.00am (UK)
Related stories
Elastomer reduces high-temperature permeability
With the recently developed elastomer compound 70 EPDM 291, Freudenberg has once again succeeded in improving the long-term permeability of O-rings, especially at high temperatures.
Seal performs under pressure
Simrit's special PPS premium pressure seal Simmerring was developed for sealing shafts in aggregates that are characterised by high system pressure.
On the other hand, fitting, in particular of the collectors, must be as simple and inexpensive as possible.
Simrit has developed the elastomer compound 70 EPDM 291 specifically for simple connections and permanent sealing of thermal solar collectors and complete solar systems.
The outstanding characteristic offered by ISC O-rings made of this elastomer is the major improvement in long-term stability.
Further reading
High-pressure seal replaces O-ring and backup
Cover Seal is a one-piece double-acting polyurethane compact seal designed to provide static sealing for rods and pistons in hydraulic or pneumatic systems at operating pressure levels abovve 5MPa.
Complete piston cuts down on parts
According to Freudenberg, the pneumatic complete piston Pneuko M sets new standards in terms of durability and frictional behaviour.
ISC O-rings and special designs made of 70 EPDM 291 are resistant in water up to 180C without difficulty.
High air temperatures (up to 150C) do not harm this material either.
One of the key parameters for the long-term stability of elastomer materials is the compression set.
The compression set is the measure of the permanent deformation of an elastomer material after the application of operating pressure over a certain period of time.
It should be as low as possible.
ISC O-rings made of the elastomer material 70 EPDM 291 have an extremely low compression set, eg 20% after 1kh of continuous load at 150C in water.
With a 1kh test at 200C in water the compression set of 70 EPDM 291 is only 50% so that the continuous use temperature limit of 180C represents a conservative recommendation.
The elastomer EPDM 281 on the other hand, which was widely used in the past, only achieves 95% under the same conditions.
In addition, these test results are based on trials involving O-rings and not the sheeting often used for this purpose, which results in much less meaningful values as they are generally more favourable.
ISC O-rings made of the Simrit compound 70 EPDM 291 also have universal approval for drinking water according to OVGW, DVGM W 270, WRC as well as the French drinking water standard AFNOR, NSF in the USA and KTW in Germany.
This sealing material also meets FDA requirements.
These seals offer an economical solution to the core problem of solarthermy - reliable hot water sealing over extremely lengthy periods.
At the same time O-rings from this elastomer compound are ideal for the plug fitting technique widely used in the solarthermy sector.
The fitting of roof or facade collector modules, valves and solar accumulators in solar technology is simplified by the low levels of friction.
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