How do urinal cisterns work?

The simplest ones have an inverted U shaped tube attached to the flush outlet and an inlet valve which allows the cistern to fill at a trickle. WHen the cistern is full enough, water flows through the tube and creates a siphon. This then quickly empties the cistern.

One addon is a solenoid valve on the inlet operated by a timer or by detecting moving people. This means that the cistern only gets filled when the urinal is likely to be used.

Hopefully somebody here is planning to check it out in the pub tonite. Can't wait to get their theories - especially after a few pints !!

Pete (fellow saddie)

I vaguely recall this being a requirement now.

Thats how the one at my place of work, works !!( is that correct ?). And if you live in a hard water area they get furred up constantly.

Dave

Quoting you Andy : -

This means that the cistern only gets

First wrong reply IMHO . How many pints consumed ?

More theories awaited !!

Pete

Sorry - mis- read your post Andy I am wrong. You are correct Apologies Pete

I'd like MUCH more information, please.

Mary

Is this penis envy again, Mary?

So why doesn't the water just trickle out when it reaches the lower edge of the top of the inverted U? I would expect that it needs a push to get enough water over the top of the U to start the syphon.

Everybody should envy what I have.

Mary

Some cisterns are filled through a valve that allows a small amount of water into cistern each time a normal toilet is flushed or a tap is opened.

The valve has a little chamber that fills with a small quantity of water. When the supply pressure to the valve drops when someone flushes a normal toilet or opens a tap, the water in the chamber is discharged into the cistern. The chamber then refills. The advantage is that the cistern only gradually fills when patrons are turning the taps on and off or flushing the toilet.

Graham

The very first cisterns worked on a tilt mechanism.

As the tank filled it would tip. Eventually it would tip so far that the water would start to syphon.

Found this on the net:

Why would they do that? Men don't wash their hands, do they???

Mary

Mary

The shape of the siphon means that as water trickles over at the start of the flush, air is prevented from re-entering up the flush pipe. The water then running from there down the flush pipe pulls the bubble of air over and down the flush pipe followed by the contents. Remember that these are also mounted high up to assist with the process.

I can't really follow that one :-)

You're not going to have the chance :-)

Mary

"Mary Fisher" wrote in news:41991720$0$2657$ snipped-for-privacy@master.news.zetnet.net:

I wouldn't go there; after a lot of casual bar work, including cleaning bogs for each gender, if your theory is correct the men were not washing their hands, but chucking paper towels in the waste bin thill they overflowed, while the hygeienic females were magically getting washed hands dry magically using hardly any.

mike

Of course they do....

Mind, they wash them FIRST so they don't get their bits dirty!