BI-MATERIAL SEAL FOR ROTATING SHAFT
Gas compressors manufacturers need to prevent the leaks of gases, especially the ones with a simpler atomic structure that are difficult to contain, due to their ability. to penetrate through seals and roughness. Moreover compressors manufacturers have the increasingly need to work at high speeds.
One of our customers, an Italian manufacturer that supplies all over the world, asked us to develop a rotary seal capable of working at high speeds even in “dry” conditions.
Analyzing the operating conditions ATP technicians detected just one constraint: a shaft diameter of 23 mm on which they could have developed speeds up to 2m /s.
Contact product: oxygen
Operating temperature: estimated 100/110 ° c
Handling: rotary (horizontal position).
Pressure: 10 bar
Lubrication: specific grease
Shaft material: hardened steel 53-55 HRC with roughness 0.2 RA.
The customer’s system was located in a horizontal position and had two seals at the edges and between which the bearings and the gas to be compressed were placed. Therefore seal’s assembly could take place in an open cavity by tightening the seal by a system of flange and counterflange. After a careful study, ATP technicians decided to opt for a bi-material seal able to withstand both loads and speeds at the same time.
The first part was realized with Sintek FPM, an elastomer capable of activating itself proportionally to the pressure. The second part, (the support/sliding element) was realized with Sintek FC, a special PTFE loaded with particular carbon fibers, capable of supporting the seal lip reducing the effect of pressure on wear and – at the same time – greatly reduces the friction coefficient, making the sealing system efficient even at high speeds. Both materials are very resistant to high temperatures that can be generated at high speeds.
Thanks to this outline and the use of such high-performance materials, we were able to retain even very thin gases despite the operating conditions involving very high sliding temperatures. – Customer Technician