A solenoid valve can be made of many different materials and in many different designs and configurations. The term solenoid is used to distinguish the operation of the valve through an electromechanical process.
The solenoid responds to changes in an electrical current. This change in current and the response of the solenoid moves the valve into an open or closed position or allows for the valve to shut off and open specific ports. With a two-port valve the action is open or close, and with three or more ports the solenoid controls the flow of the liquid, gas or steam through the valve to different outlets.
The Use of Plastic
While many types of applications use solenoid valves made of different metals and alloys, high purity systems require special materials. A plastic solenoid valve for these applications can be made of PEEK and Polypropylene, with PTFE bodies and wetted surfaces.
The use of PTFE or Polytetrafluoroethylene is ideal for high purity types of applications. This is the material commercially known as Teflon, and it offers a non-stick, highly chemical and corrosion resistant surface.
The addition of PTFE to the plastic solenoid valve wetted surfaces prevents media from building up in the valve and causing corrosion damage to the surface. With the extremely low friction caused in passing through the valve, it has minimal impact on system pressure or flow rate.
What to Consider
With a well-designed, quality plastic solenoid valve, the coil itself will be completely isolated from any possible contact with the media. This not only extends the life of the valve but also dramatically reduces valve failure.
In applications with extremely elevated temperatures or large temperature variations, or when specific types of seals and o-ring configurations are required, look for a manufacturer specializing in plastic high purity valves