High Pressure Solenoid Valve.
High pressure solenoid valves are typically defined as ON/OFF control valves for fluids and gases from 20 to 500 Bar and beyond.
Body materials:
Typically, Stainless Steel AISI 304 or 316 stainless and sometimes Brass but not Aluminium or plastics as these do not have the strength required to hold high pressure fluids or gases.
Design:
Typically, with an internal piston for strength however for lower pressure ranges under 25 Bar nylon reinforced rubber diaphragms can be used, smaller high pressure miniature valves such as 1/8 and 1/4 ported valves sealing is direct via the armature, so no piston is required but in these instances the orifice or flow path through the valve will be quite small restricting flow.
Function:
The function of a valve is defined in two ways:
1. The number of ports and the number of positions. For instance, a 2/2 way solenoid valve will have 2 ports inlet and outlets with 2 positions open or closed.
2. The failsafe position with electrical power removed, typically normally closed with power to open, however some manufacturers produce normally open valves that require power to close. Typically, in high pressure applications it is recommended for safety reasons to use failsafe closed, so upon electrical power failure the valve returns to the closed position preventing flow.
Example: 2/2 way normally closed = 2 ports 2 positions (open or closed) with failsafe closed position.
There are instances of 3 way high pressure valves, used for diverting flow, these are referred to as 3/2 way 3 ports 2 positions. These are not very common for high pressure applications but again some manufacturers do produce these, but pricing can be inhibitive, and it may prove beneficial to use two 2/2 way valves on a "T" adaptor, so flow can be controlled On/Off to both outlet ports rather than simply a choice.
Sealing:
High pressure solenoid valves are by definition designed to withstand extreme forces, in these instances typically PTFE is the seal material of choice, PTFE has excellent resistance to wear and chemical attack but if not manufactured correctly will give sealing problems as PTFE is a hard non elastomer seal.
Examples of high pressure solenoid valves.
