Torque Data on motorised valve

[shabbirvora]

Hello to all;
We are evaluating data for High Bore Gate / Globe Valves for Hydro carbon service.
The valves in question are 30 to 42" Gate / Globe valve, #300 with 13%Cr trim; some of which are to be automised.

Can any body share torque data(for evaluation) for the above valves or suggest some link where we can find the data.(I have tried many vendor portals but could not find it)
And also share some usefull facts in selection when it comes to electric actuation.
Thanks

 

[JimCasey]

Primarily you don't use torque to actuate a gate or globe valve, you use THRUST.

Thrust is a function of the size of the valve, the internal construcion of the valve(Balanced or not, etc.) the type of packing, the differential pressure, process fluid density and lubricity. This information should come from your valve vendor after you define your process data to him.

Once you know the thrust required, you can look at the speed you need for the valve to stroke, and the length of the stroke. Torque at this point would imply an electric actuator. Select the thread for the actuator shaft if it is not integral to the valve stem, then you can calculate the torque required based on the thread form, thrust required, efficiency of the thrust nut. This information is most likely available from the actuator manufacturer you choose; Limitorque, Biffi/Tyco, Rotork, Auma.

 

[BigInch]

It would be a very good idea to place in the procurement specification a clause stating that the actuators and valves shall be assembled and tested in the fabricator's shop before shipment.

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[Ashereng]

With a motorised actuator, if you need more "torque", you can also use a gear box, if you can live with slower closing/opening speeds.

In my market, the common manufacturers that are used are:
- Rotork
- EIM
- Jordan (Rotork) for high starts/hr

A globe valve is usually used for control. As such, we do not usually use an electric actuator - we use air. The reason is cost - air actuator is usually cheaper for control functions when compared to an electric one. Also, with a pneumatic actuator, you can easily "fail" the valve to either open or close. With an electric actuator, in order to "fail" the valve open or close, you are looking at a UPS.



"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[BigInch]

Absolutely, just don't oversize the gear box so that it can shear the valve stem.

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[JLSeagull]

Torque switches should be set in the actuator to stop the motor at the end of the stem travel. The actuator supplier can advise the data required. You need to obtain the valve and actuator data from the actual suppliers. A common requirement for motor operated valves is 12-inches travel per minute. This would take a while to close a 42-inch valve.