Put a plastic seat inside a steel valve, and there's no question about which part is most likely to wear out first. With some models, a bad seat means tossing out the entire valve. With many models that have replaceable seats, the design requires a seat big enough to manipulate by hand, making the seat more susceptible to swelling from chemical interaction or high temperature.
Swagelok engineers have come up with a new alternative, the new lines of DP and DF Series Valves: DPX and DFX replaceable seat diaphragm valves. They are designed with a tight-fitting seat that offers minimal entrapment areas and a short height to limit chemical and thermal expansion. With the use of an installation tool, customers can put in new seats right at the job site.
These two new lines were designed with advanced semiconductor precursor delivery in mind. They come in manual or pneumatically actuated models.
The installation tools make it easy to install a new valve seat without risking damage to the sealing surface, because the seat never touches your hands. The new seat comes in a protective holder that ensures that the seat is installed in the correct direction. It also compresses the seat diameter to enable a pressed fit into the pre-staked valve body. You get a tight seal with minimum entrapment areas for high purity systems.
To remove the old seat, use the seat removal tool that comes with the replacement kit. You simply disassemble the valve, screw on the removal tool nut, and rotate the removal arbor. The tool never touches the body, and the seat lifts right out.
To put in the new seat, just place the carrier in the valve — it's designed in such a way that you can't put the seat in upside down —screw on the installation nut and screw down the installation arbor. That's all there is to it.
The kit also comes with a diaphragm and a support diaphragm for rebuilding the valve.
Kits are available in quantities of 25, 50, 100, and 200. You can get detailed specifications and download the valve catalog, seat replacement instructions, and presentation here.
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