Actuator Torque for Butterfly Damper

[Paco80]

I am trying to determine the actuator torque required for my metal seated, concentric butterfly damper for smoke service in a fire heater.

Butterfly Damper Specifications
- 58" diameter
- 0.04 PSI dP
- 630 degrees F
- intended for SMOKE service
- sealing system is 316SST on 316SST.

I intend to use a pneumatic actuator.

Does anyone knows any design standard for sizing damper actuators?

Thanks in advance,

Paco.

 

[gerhardl]

1. The torque will not be easily determined theoretically, as this will(as usual - for all valves/flaps) be determined on seat closing and release torque, resistance from bearings, weight, etc. Vertically or horizontally mounted? Geometry torque? Temperature variation/expansion or crimping, wearing over time? Residue and sticking properties?

One idea is to presume the same as a'standard' valve of same size.

2. On the other hand I would personally prefer an electrical actuator for this purpose. Among other things you could easily add an exra gear- box if short regulating time is not an issue. This will also give less volume and cost for the actuator. (Note not necessarily lower tha pneumatic) An electrical actuator of high quality would in addition include up til a full recording and regulating 'cabinet' included in standard or additional standard equipment. The total cost could be well under complete pneumatic regulating equipment with instrumentation.

 

[DRWeig]

For a butterfly, I'd consult the damper manufacturer. They'll have an answer.

There are some rules-o-thumb for opposed blade / parallel blade rectangular dampers, but I've never run across one for butterfly style.

Best to you,

Goober Dave

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[Paco80]

Thanks all for your input.

I will contact the manufacturer to assess an actuator.