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Drawing for a miniature quarter turn valve

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Brian Abbott23/06/2019 20:53:12
456 forum posts
88 photos


Does anyone know where i can find a drawings for a miniature quarter turn isolation valve ?


Edited By Brian Abbott on 23/06/2019 20:55:51

Brian Sweeting23/06/2019 21:28:53
437 forum posts
1 photos

Are you looking for construction drawings or layout drawings, also what size miniature?

Basic valve layout/data .... **LINK**

Edited By Brian Sweeting on 23/06/2019 21:29:20

Brian Abbott23/06/2019 21:41:37
456 forum posts
88 photos


I need to make a replacement injector isolation valve, many of the comercial places make them but i need one with a flane mount, what i am after is a design i can adapt.




Edited By Brian Abbott on 23/06/2019 21:42:36

Nigel Graham 223/06/2019 21:56:53
720 forum posts
16 photos

Note that the link opens the details for the sort of valve common on plumbing systems, and these are very simple but highly restrictive to flow.

I sectioned one recovered from 15mm plumbing, to see if it's possible to make a miniature version, and found the port through the ball is half the pipe bore, so one-quarter cross-sectional area!

The operating spindle has a screwdriver-like tip that engages a shallow slot cut across the ball (verify the orientation before slotting).

The spindle is captive by a shoulder, so the valve is assembled by inserting the spindle from inside, then putting in the far O-ring seating, the ball itself turned to the slot engages, the near O-ring then a special circlip that locks into a groove in the valve wall.

A friend in the plumbing-trade vouched for the restriction they offer, but said full-flow versions are available.

It ought be possible to make full-flow versions for much smaller pipe sizes; though rather fiddly to machine. I'd use a manufactured bronze or stainless-steel ball, but I don't have a ball-turning attachment. Besides, it is likely to be of greater accuracy and sphericity than I'd hope to achieve!

To replace the circlip with something easier I'd be tempted to use a thin push-fitted sleeve trapped by the end-fitting or union, but beware the risk of losing the internal components when disconnecting the fitting.

Alternatively look on the boiler-fittings drawings for almost any miniature steam locomotive or traction-engine. The quarter-turn valves on these are usually plug-cocks, but you should find a design you can adapt to your needs.

duncan webster23/06/2019 23:12:18
2737 forum posts
40 photos
Posted by Brian Abbott on 23/06/2019 20:53:12:


Does anyone know where i can find a drawings for a miniature quarter turn isolation valve ?


Edited By Brian Abbott on 23/06/2019 20:55:51

I'll send you one tomorrow when I can prise SWMBO off the other computer. you'll have to pm me your email address

Paul Lousick24/06/2019 07:39:04
1501 forum posts
572 photos

Globe valves and ball valves can also be used for controlling steam supply to injectors. If you need a flanged type valve, a commercially available valve could be modified by screwing or silver soldering onto a flange.


Brian Abbott24/06/2019 08:18:28
456 forum posts
88 photos

Thanks guys,

Duncan, will drop you my email address.


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