Float valves which are OK if submerged

I'm after a float valve of some sort which will not get damaged if it is completely submerged. I want to have a tank which is mostly filled from local sources of water but, if the local sources dry up, then the float valve will maintain a foot or so of water in the bottom of the tank from the mains. (I guess there will have to be strict non-return precautions to conform to water byelaws too)

So, I need a float valve that won't mind being underwater, I suspect that the 'standard' sort of cold water tank valve with a big spherical float won't survive being under water.

Would a Torbeck valve be OK, or do they include the flushing mechanism which I don't need?

Reply to
tinnews
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filled

non-return

spherical

mechanism

You could used the low pressure diaphragm switches (*) used to set the levels in washing machines, and have them controlling solenoid valves - again from washing machines - so not only is the switch not submerged, but the two sources of water can be totally isolated.

AWEM

(*)They use a column of air trapped in a tube, as the level rises so does the pressure in the tube and the switch triggers - usually have two independant set points that are tweakable with a little screw

Reply to
Andrew Mawson

As Andrew said, I would be inclined to use an electrical solution.

A float switch like this:

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a solenoid valve from a washing machine.

Oh, just found this: - perfect

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to use a washing machine solenoid valve and a tundish for non-return isolation.

Reply to
Dave Osborne

Doh, just noticed page 2 of the pdf where there is a non-electrical solution as well. Mechanical float valve on a piece of string. Clever!

Reply to
Dave Osborne

I'd rather not have a power (electrical) operated valve if I can avoid it. I could do something similar to what you have described with a float switch which is definitely OK submerged.

Reply to
tinnews

I had a set-up which did *exactly* this, my design was amazingly like what's described in the above link to a PDF, down to using a similar plastic box to put it in.

However they don't survive all that long in an outdoor environment, even in a shed (which is where mine was). The combination of occasional freezing and our very high mains water pressure soon breaks something.

(I guess I may have the same freezing problem with any sort of float valve but at least they're cheaper)

The

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site is a bit worrying, no indication of prices anywhere that I can see.

Reply to
tinnews

That's exactly what I want, maybe I can simply add a bit of string to a 'conventional' float valve of some sort. It does look as if the valve they're using is quite like some of those available from BES.

I just get this nasty feeling that Halsted Rain charge a silly amount for the device.

Reply to
tinnews

When I've seen this requirement the float has been on a long arm, with a bend at about 10" from the pivot, allowing the valve to be above the water level and the float below. If the height of the tank is too much for this arrangement then the float could be attached by a cable to the arm, and couterbalanced by the cable extending over a pulley to a weight. This arrangement of float and weight is often used for operating electrical level switches, but should be just as good with a mechanical "water" switch.

Reply to
<me9

Alternative simple idea: Brass cistern valve and extend the arm downwards? Could be done with the vertical extension being a bit of

a) 15mm copper pipe, hole drilled in one side near the end;

b) Cut off float and 2" of brass arm;

c) Insert remaining arm from valve into side of copper tube and solder;

d) flatten other end of copper tube round the bit of arm that takes the float and solder there.

Then you have:

==== =====-------------||- ==== || || || || || || || || || || || || || || || || || | O O O O O O

If the valve and arm are brass, I don't see why this shouldn't work. The turning moment on the valve will only be a little worse than a normal mode ball valve where the float becomes fully submersed (as could happen in a CH expansion+fill tank)

And brass valves are highly maintainable. If the vetical drop is long, it might be necessary to put a side baffle in to constrain the float to vertical movemnet to reduce twist stress on the valve arm hinge.

Reply to
Tim Watts

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