What is multi-turn ball valve?

[onrush]

Dear members,

What is the multi-turn ball valve?

Is it orbit ball valve?

If so, what is the purpose to use that kind of ball valve?

Thanks in advance....

 

[insult2injury]

Orbit makes a multi-turn ball valve.

It's a ball valve where the stem/indicator rises as the valve is opened to indicate position. I've seen quite a few used in safety services because the valve position can be identified from a distance away and the valve can be full-ported.

I2I

 

[gerhardl]

This was a new one for me.

Checking Camerons homepage I find that the designation Cameron uses is 'Ballvalve with rising stem'.

Multiturn is normally used for valves with a construction where the closing element does not move 90 degrees, eg. normally for globe or gate valves with threaded stems, requiring several turns to close and open. Multiturn is not a 'normal' for BFL or ball valves.

As an example a double eccentric ballvalve with a gear requiring several turns to close, but where the ball moves 90 degrees, is not called a multiturn ball valve.

Multiturn is often used to describe the actuator movement for an actuator if the actuator (or gear) has to be turned several turns to close, even if this is mounted on a 90 degre closing valve.

Finally the 'academic' point:

Even if the special Orbit ballvalve has a stem requiring several turns to close or open, and are 'nicknamed' multiturn, I would like to reserve the 'multiturn' designation for actuators and globe and check valves, and in this case use, as the factory does, 'rising stem ball valve'.

(OK, I admit this is perhaps going too far into details and argumentation, but anyway.... ! ;-) )

 

[Joesteam]

Here in NYC, we use ball valves for tight shut-off on district steam at max 200 psig. 1/4 turn valves are not allowed in this service for fear of opening quickly and causing water hammer or thermal shock. So, we use a multi-turn gear operator on the steam rated ball valves. So, like the Orbit, it is still a 1/4 turn valve on the inside, but has a multi-turn gear operator on the outside.

Joe Lambert

http://www.control-associates.com/