The table below provides details of some of the more common materials and approvals for our extensive range of O –rings. The list is not comprehensive so please contact us to discuss your requirements or for technical data sheets pertinent to your application.
(FOOD & DRUG APPROVED)
|PEROXIDE CURED||STANDARD LOW TEMP
|SPECIAL LOW TEMP||TALC FINISH||SILICONE OR MOLY OIL FINISH||WRAS
(APPROVED PORTABLE WATER USE)
PEROXIDE CURE: NOT NORMALLY SUPPLIED IN THIS FORM BUT THOSE MARKED CAN BE
A MINIMUM WORKING LOW TEMPERATURE IS SHOWN ABOVE FOR OUR STANDARD COMPOUNDS WHERE INDICATED A SPECIAL FORMULATION IS AVAILABLE TO WORK AT LOWER TEMPERATURES.
Back-up rings are plastic or rubber rings used to prevent the O-ring from entering the clearance gap. When high pressures are exerted on the O-ring, its soft rubber material can be forced into the clearance gap causing the O-ring to extrude. The hard back-up ring material will keep the O-ring material from flowing into the gap, which will prevent premature failure.
Please download our back-up rings .pdf for further information
BS STANDARD O RING DIMENSIONS
Also available to download is a list of the British Standard sizes
A chemical compatibility reference for both dynamic and static sealing applications is also available for reference.
Failure to select the correct materials or products can result in damage to plant and equipment and personal injury. In specific applications, particularly where critical conditions exist, we suggest you contact us and we will consider with you the most suitable material or product. However, information supplied by William Johnston & Company Limited is intended only as technical co-operation and as a guide to the various uses of different products. No warranty is given in respect of information or recommendations by William Johnston & Company Limited which are only given for guidance and without any guarantee. The customer must satisfy themselves on the suitability of the material or product for the intended purpose. The correct fitting of products is the responsibility of the customer.