Extended stem motor operated valve

  • Thread starter Mohammad Reza Haghighat
  • Start date

Thread Starter

Mohammad Reza Haghighat

As the process area is not accisable during the plant operasion (because of toxic gas)for maintenance objectives the actuators of motor operayted valves should be located inthe safe area, and its rotation should be tramnsfered to the valves by the long stem,first of all have you ever seen such a solution?are there any special manufacturer for such MOV's?

My experience of extension pieces are in high temperature installations (protecting the actuator components) and Operator accessible location requirements (eg. Sumps where Toxic gas may settle and in sluices above liquid level).

But as for a consideration for maintenance, that's a new one on me. Of course we should consider the maintenance aspects during design, but then we'd also prefer the vendor with less breakdowns.

Perhaps the question can be posed to the valve experts on http://www.valveexperts.com

Hope this helps

Richard Evans

In the nuclear industry it is quite common to see a 'remote' actuator. The electric drive is sometimes located on a pedestal in a room on a floor above.
The stem itself is not commonly 'extended'. The upper portion of the yoke will include a rotating threaded bushing (the stem nut) that is driven by a actuator driven shaft, or torque tube.
Sometimes it is necessary that the driven shaft 'go around corners'. The driven shaft will then have to be fitted with gearboxes, universal or even 'CV' joints.

Tomy Zacharia

Dear all,

In the petroleum pipeline Industry, valve stems of 2.5m or longer are available to locate valves under ground and the actutaors above ground. This could be one of your soln.s.

Tomy Zacharia