High temperature operator for valve

[lloydbrown]

I need to install a small valve inside an oven operating at 150C. The oven wall is also a contamination control boundary so the valve operator will have to be inside the oven. Can anyone recommend a source of commercial valve operators which would operate in this service? I have sketched out a spring-to-close, air-to-open metal bellows actuator which could be designed, but I would rather purchase a commercial product. Any suggestions?

 

[ihg]

On-off or proportional control?
At 150C, you are within the reasonable range for Viton or Kalrez seals, at least for an on-off actuator. Proportional control is touchier as you cant afford any stiction or hysteresis, and even an old-fashioned pneumatic positioner is likely to worry at 150C. But I would suggest go talk to your most cooperative control valve salesman; you may be surprised.

 

[lloydbrown]

The actuation is on-off. I didn't mention the size of the valve. The maximum size will be 1/4" tube. I would prefer metal bellows sealed valves, but would live with Kalrez if necessary. The valve and seal bellows will be Hastelloy C-276. A Kalrez seat would be fine. Viton won't handle the chemical service.