http://s377.photobucket.com/albums/o...%20Jan%202011/

or where I might obtain something similar?

It is fitted to an old Permutit water softener that was installed in about
1980. This valve is not OE and was retrofitted under warranty some while
later.
Basically it is a clear sealed plastic cylinder with a floating ball within.
It was filled with gunge and I have cleaned it as best I can with
detergents, agitation, mild bleach solution, more agitation and fresh water.
Quite a few times. I can find no way of dismantling without busting it.

I think the floating ball, or housing, may be worn as the valve is allowing
fluid to bleed through, this is allowing the brine reservoir to fill with
water.

In use the valve is mounted vertically. The short white hose connects to the
machine and the longer black hose connects to a gauze strainer within the
brine reservoir. The floating ball seals at the bottom and does not seal at
the top.This baffles me a little but I'll get my head round it.

Any old Permutit engineers around?

Many thanks,

Nick.