Piston seals
Piston seals or piston rings are used in pneumatic cylinders for fluid sealing and are designed to ensure that pressurized fluid does not leak across the cylinder head as the system pressure pushes the piston down the cylinder bore.
The best sealing capacity of a double-acting cylinder, capable of sealing dynamic pressure from both sides (bidirectional), is achieved by choosing a double-acting seal.
A piston design where two single-acting seals on the piston for a double-acting cylinder are used can easily give rise to a breakdown. The reason is that a very high pressure can be trapped between the seals.
Piston seals, both single and double-acting, can be designed for and used with integrated or separate back-up rings and guide rings.
What are the key design considerations for selecting a pneumatic piston seal?
When selecting a pneumatic piston seal, it is essential to consider factors such as the operating pressure, temperature range, and the type of fluid involved. The seal material must be compatible with the media it will encounter. For instance, Piston seals type GUM are designed to be oil resistant, making them suitable for pneumatic pistons. Additionally, the seal's design, whether it is a single acting or double acting type, also impacts its performance.
How can the performance of a piston seal be improved in high-temperature applications?
To improve the performance of a piston seal in high-temperature applications, it is crucial to select seals made from high-temperature resistant materials such as NBR or FKM. For example, the Piston seals GDEM are specifically designed for single acting seals and can withstand higher temperature ranges while maintaining effective sealing. Proper lubrication and installation techniques also play a vital role in enhancing seal longevity.
What are the advantages of using U-ring piston seals over other types?
U-ring piston seals, such as the U-ring TMP 21, offer several advantages including ease of installation, low friction characteristics, and efficient sealing performance. They are particularly effective in dynamic applications where they can provide reliable sealing under varying pressures and conditions. The design of U-rings allows for self-adjustment during operation, which helps to maintain effective sealing over time.