"Dave Osborne" wrote in message
...
wrote:
There seem to a number of different sink traps - 'P' trap, bottle
trap, antivac bottle, antisyphon etc

Can some kind soul point me to a source of information about the
relative differences, and uses please. TIA

Well, as I'm sure you're aware, a trap is basically a U bend which holds
(i.e. "traps") some of the water you flush down the sink. This is is so
that bad smells from the sewage system can not get back into the room.

The different types simply have the outgoing waste pipe presenting at
different angles.

So, with a P trap, the waste pipe exits horizontally. A bottle trap also
has horizontal exit, but takes up less space.

With an S trap, the waste pipe exits vertically. A slimline pedestal trap
also has vertical exit, but takes up less space.

Anti-syphon and anti-vacuum are (as far as I know), different terms for
the same thing.

Normally, the pressure in the sewage system is the same as atmoshpheric
pressure. This means that if you had (say) a conventional P trap made out
of clear plastic, you would notice that the water levels either side of
the U bend are equal.

However, under certain circumstances, the pressure in the sewage system
can become reduced which means that the residual water in the U bend gets
sucked down the drain and the smell-sealing effect stops, leading to a
nasty niff in the room.

AIUI, Anti-syphon bottle traps have clever bits inside that allow the
pressure to equalise without losing the residual water in the U bend
(which isn't actually a U bend in a bottle trap, but does the same job).

http://www.marleyplumbinganddrainage...496/traps.html

Thanks for that Dave, very interesting.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk