NEWS
terial combinations, a result of the r e c e n t d e v e l o p m e n t s by John Crane Polymer Engineering. A new grade of silicon carbide provides excellent wear r e s i s t a n c e a n d f a c i l i t a t e s a wider spectrum of operation, i m p r o v i n g b o t h p e r f o r m a n c e and reliability.
The bellows itself is protected by an innovative band design, which m a i n t a i n s a low stress environment. The drive bands have intermeshing tags which create a positive metalto-metal drive through the seal, and also promotes high grip to the shaft and greater torque c a p a c i t y . W i t h o u t r e q u i r i n g costly set screw drives, this d e s i g n r e d u c e s failure from slippage on the shaft, while increasing the operating envelope. The positive drive b a n d s also enable bi-directional operation, eliminating the necessity to stock both clockwise and anti-clockwise seals.
Other design e n h a n c e m e n t s contribute to increased seal life. A balanced face design facilitates low r u n n i n g torque -and thus, low heat generation and wear. The new open coil design of the spring reduces the change of clogging, thus improving the seal's operating parameters. The optimized design also evens the load distribution, thereby reducing uneven wear.
The seals have been tested for more t h a n 100 000 hours inhouse and with customers in the field.