What are the applications of Spring Return handles (Deadman handle) for ball valves? 4

[Bharti__]

Hello!

I was refering to some companies who are manufacturing ball valves, On their sites they are providing an option of spring return handles (they also call it Deadman handle). This kind of handles are something new that i found during surffing so, I am wondering what can be the aplications of this kind of handles?

on some sites, i found that these handles are used for refueling, Sampling, drains etc. but it is not giving clear picture to me for this handle applications!If this handles are used widely then what kind of design considerations to be taken care for this handles.

In short, my questions are:

1) What are the applications of deadman handles in ball valve?

2) What are the design considerations taken in care for this kind of handle?

Thank you in advance!

 

[Danlap]

Hi,

Not really my specialties, but sometimes I face this condition every now and then.
Application?
-Ball valve that only requires from fully open to fully close or vice versa by means of a swift quarter turn (read: not using gearbox or handwheel). Therefore it is limited to normatively small sizes and or ‘medium to small’ pressure e.g. 2” – 600# or smaller
-Once opened or closed, a swift action to close or open is required to attain non-excessive product’s volume from the outlet. Since the frequent of operation is quite often, shall valve’s reverse action (close or open) is done manually by hand there are some concern that the direct & frequent rapid closing/opening may damage the spindle or ball vs seat sealing area. Therefore a relatively uniform Break Torque Close/Open (BTC/BTO) should be assured, by means of constant spring’s torque
For example: sampling valve, filling line, etc.
-Some environmental leaking incident happened due to operators’ forgot to open/close the valve. Especially in remote places (location relatively far from the control room), or some arrangement that is prone for operator forgotten to open/close some valves
-Valves are part of sequential procedure. For example line consist of valve A-B-C-D and most of the time this is a single operator task to open/close it. Before opening valve C, valve A should be close first. Then valve A can be equipped with spring return

Part of consideration:
Let say valve to be normally close by spring. Then not to be simplified:
Break Torque Open or Cracking force > spring return force + Delta P (maximum differential pressure in close position between upstream and downstream) + friction between Ball & Seat(s)
Since cracking force (valve about to be open/close) is usually bigger than sustained force (once the valve has been “cracked”) then sustained forced can be neglected
Ideally the spring force should be > break torque close. This to ensure that valve will be properly close once handle is released
And of course all the value above should be smaller than MAST

However, the cracking force should be within ergonomic range for example less than 440 N for 120 mm lever (ISO 6385). The idea is that common operator may use his/her own ergonomic strength is sufficient to “crack” the valve, without any prejudice that valve is stuck or cheater bar is required.
By that respect, normally spring return application is more common for soft seated (less friction between Ball&Seat) rather than metal seated.

Maybe others have better experience or can tweak my narrative above.

Kind regards,
MR

https://nosuchvalve.com

All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected

http://www.eng-tips.com/faqs.cfm?&rat1=2&fid=376

 

[LittleInch]

Danlaps answer is comprehensive.

Applications? : Anywhere you need flow which is undertaken by manual means (handle) and where you need an automatic closure. Can't say I've ever seen one on any facility I've been involved in but danlap has identified a few possibilities.

Design considerations:
Surge / water hammer if the valve closes very rapidly
Reliance by the operator that the spring will close the valve every time he or she lets go
Something being hit by the handle as it returns to closed position
Additional force required by the operator to open valve against valve force plus spring pressure
Something getting in the way of the handle preventing full closure
Operators finding ways to hold the valve open and letting go of the handle



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Danlap]

Thanks LittleInch,

for addressing the additional process and risk or operational consideration.

Kind regards,

https://nosuchvalve.com

All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected

http://www.eng-tips.com/faqs.cfm?&rat1=2&fid=376

 

[Bharti__]

@littleinch

Same as you! I have not seen this kind of facility on any valve, too. thats why it sounds new for me but most of the well known companies like bray, apollo etc are providing this option so, wondering that in what kind of industries it can be used and what can be the comparative share in the industries compare to manual handles and spring return actuators!

 

[Danlap]

Bharti,

Most refineries have hundreds of spring loaded ball valve, dozens of spring loaded globe valve (usually for blow-down purpose) and some numbers of sampling valves (usually for specific volume purpose).
It is not a standard feature for most manufacturer, but indeed Flowserve and other brand provide this option. Why they don't brag about it simply to avoid dispute since there is a possibility shall valve not fully closed after handle is released

Kind regards,
MR

https://nosuchvalve.com

All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected

http://www.eng-tips.com/faqs.cfm?&rat1=2&fid=376

 

[bcd]

I frequently see them in buildings where they are used in water pipes on fire suppression systems. Have also seen them on gas lines in buildings. Some have links that melt at specific temperature and cause the valve to open or close. Depends upon the spring direction. If there is a fire, I expect the spring handles on water lines to open, and the valves on the gas lines to close.

 

[Ehzin]

An example I've seen is for automatic closure for a sample location. A sample bomb (Unsure of technical term) will be hooked up with SS hose on each end and all other valves lined up to begin a sweep to draw a sample and lastly the spring loaded ball valve will be opened. In the event that the hoses disconnected the operator doesn't need to remain right at that location to close it. Can move out of the immediate area depending on the release. The valve closing should limit flow to the point where it can be shutdown or upstream valves closed in a safe manner.

Thanks,
Ehzin

 

[SceneryDriver]

We have spring loaded ball valves on the 55gal drums of carpenter's glue in the carp shop. Apparently, years ago, some muppet carp forgot to close the valve after filling their glue bottle. 55gal of carpenter's glue is tough to clean up.


SceneryDriver