Identify this type of non-return valve?

[Richard Sterry]

Can anyone identify the type of non-return valve shown in this photo please?

only looked inside briefly, but it appeared to consist of something rather like a semi-rigid plastic duck's bill - or perhaps more like the flattened neck of those balloons that are designed to make a very loud (and rather rude) noise when released!

You will appreciate that searching for "non-return valve" is a bit too general, so a more specific generic or manufacturer's name would be a great help to me.

Many thanks

[Set Square]

Not totally sure - but it could possibly be a double check valve designed to be put in a cold water supply to outside taps etc., to stop any dirty water from syphoning back into the mains if the mains supply fails.

[BigWallop]

Where is this fitted, and to which type of appliance? Is it on the drainage from a condenser boiler? I only ask because it looks like an anti-syphon waste trap rather than any non-return valve I've ever seen. Saying that, new technology seems to be overtaking me at the moment on plumbing parts. :)

[IMM]

My God, and this one is telling me how pumps work. I despair. It is a HepVo trap. Go to the hepworthplumbing web site. I can't be bothered educating fools.

[Set Square]

Then it's a good job that some of us have greater generosity of spirit! I did admit that I wasn't sure about that one, never having seen anything quite like it.

Despite your attitude, I have spent a considerable amount of time this evening trying to educate *you* (and I will leave others to judge whether or not that is "educating fools") in some very elementary principles of physics - which should be second nature to any "professional" engaged in anything involving water circulation.

[IMM]

On what? Not heating water and associated controls me boy. Never in a million years. You are deluded.

[Richard Sterry]

Excellent, a positive I/D on the valves - thanks for all replies. I did not explain the application. They have been used in the waste outlets of a large clinical analyser, and the copper fittings are to permit braided (reinforced) hose to be connected conveniently. I do not have access to the contractors who sourced the bits, so was unable to ask them what they had used.

The valves help prevent wastes (which are very frothy) from one (active) machine being pumped back up the waste outlets of another (idle) machine, in the case where there is a slight pressure build-up in the drain piping. The drain system cannot be vented in the vicinity of the machines, otherwise everyone in the lab would soon be knee deep in froth, so a small positive pressure in the drain system local to the machines is inevitable.

Many thanks again for an excellent result. Unfortunately, the Hepworth UK site is 'down' at the time of writing (typing?), but the Hepworth New Zealand site, and some suppliers' web sites, had the necessary info.

Rick