Pneumatic Diaphragm Valves
Pneumatic diaphragm valves let a gas panel, valve manifold box or tool controller open and close a high purity line remotely. Valonix air-actuated valves are normally closed, spring-return units driven by 60-90 PSI clean dry instrument air or nitrogen.
Because the actuator is completely isolated by a metal diaphragm, automation adds no contamination path. The same wetted construction used on manual UHP valves is retained, so an automated panel keeps the same purity level as a manually operated one.
Normally closed versus normally open
Specialty gas panels overwhelmingly use normally closed valves: loss of instrument air or power closes the gas line automatically. State the fail position clearly on the datasheet, especially for toxic or pyrophoric gases where safe state is part of the system design.
- Spring-return normally closed is the standard
- Fail-safe closure on loss of air or power
- Position indication available for panel feedback
Actuator supply and response
A 60-90 PSI supply is typical; three-way switching valves may require 70-125 PSI. Keep the supply clean and dry, because moisture in the actuator line can freeze or corrode the piston. Solenoid valves should be mounted on the panel, not on the valve body, to simplify maintenance.
- 60-90 PSI standard actuator supply
- 70-125 PSI for three-port switching versions
- Clean dry air or nitrogen only
Integration into VMB and VMP panels
In a valve manifold box, pneumatic diaphragm valves isolate the process line, the purge line and the vent line. Interlocks sequence them so purge always precedes process gas introduction. Valonix supplies the same body in 1/4 in through 1 in sizes so a panel can be built with one valve family.
- Process, purge and vent isolation from one family
- Consistent face-seal envelope across sizes
- Compatible with standard gas panel layouts
Valves in this category
VX4-LPVX4 Low Pressure UHP Diaphragm Valve
- Port size1/4, 3/8
- Max. pressure300 PSI
- Cv0.27
VX8-LPVX8 Low Pressure UHP Diaphragm Valve
- Port size1/2
- Max. pressure300 PSI
- Cv0.70
VX12-LPVX12 High Flow UHP Diaphragm Valve
- Port size3/4
- Max. pressure300 PSI
- Cv2.8
VX16-LPVX16 High Flow UHP Diaphragm Valve
- Port size1 in
- Max. pressure300 PSI
- Cv3.5
Typical specifications
| Actuation | Pneumatic, spring return, normally closed |
|---|---|
| Supply pressure | 60-90 PSI (70-125 PSI three-way) |
| Working pressure | 150-3000 PSI depending on model |
| Port sizes | 1/4" to 1" |
| End connections | VCR, butt weld, compression |
| Options | Position indicator, solenoid interface |
Frequently Asked Questions
What air pressure is needed to actuate the valve?
Most models need 60-90 PSI of clean dry instrument air; three-way switching versions need 70-125 PSI.
Are pneumatic valves rated for the same pressure as manual ones?
Usually lower. Check the pneumatic rating separately, because actuator thrust limits the maximum seat pressure.
Can I get a position feedback signal?
Yes, position indication can be specified for panel interlocks and tool control systems.