|
Solenoids get tougher seals
|
13/04/2003
|
| |
Problem: Solenoid valves from a simple but staple part of many types of industrial equipment, they also see significant airplay in the world of fluid handling for precision applications such as medical dosing, fluid analysis and laboratory measurement.
A problem can exist with the fact that the majority of inert solenoid valves use a solid PTFE diaphragm for sealing – separating the fluids from the operating parts of the solenoid. PTFE, although very flexible and inert, is not all that resistant to abrasions.
If fluids containing particulate matter are being controlled by a solenoid valve then constant abrasion of the PTFE diaphragm can eventually lead to leak paths across the valve seat which, in turn, may allow fluid to flow even when the valve is in the closed position. In high accuracy applications this can lead to spurious or inaccurate results.
Solution: Asco Joucomatic has developed an inert isolation valve which significantly reduces the possibility of seat leakage.
The inert isolation valve (series 462) uses a resilient seal against the valve seat while still maintaining the PTFE seal as the rigid structure of the diaphragm. The resilient part of the seal is made from Kalrez, a DuPont Dow elastomer, which, as well as offering excellent sealing characteristics, is also inert enough to be used with the majority of solvents and reagents used in analytical instruments.
If any articulates do find their way onto the valve seat, the Kalrez seal will tend to conform around them providing a better seal than PTFE on its own.
Applications: Initially developed to solve a problem in the medical and analytical market. The functionality this type of seal hybrid offers will not be lost on other applications, where precision flow and accuracy of results are high on the agenda.
Since laboratory real estate is also at a premium, the series 462 is only 25.4 x 37.65mm in size. The standard body is also made out of Peek, a strong, inert material, to prevent cross threading of the valve body – another common problem according to Asco.MF
Asco Joucomatic
|
| |
Author
Tom Shelley
|
| |
| |
|
| Email this article |
|
|