On Sun, 07 Dec 2008 11:44:49 +0000, John Stumbles wrote:

On Sat, 06 Dec 2008 23:40:14 +0000, Ron Lowe wrote:

All the hydraulic and compressed air pipework I deal with at work seals
at both ends of the coupling when disconnected. Why the heck is it not
fail-safe in this error condition?

Hydraulic obviously they don't want oil escaping from either side of the
coupling when it's disconnected.

The compressed air fittings I've seen are like gas cooker points in that
they isolate the /supply/ when disconnected, but there's no point in
isolating the load end: just more gubbins to make and install for
absolutely no purpose (unless one is trying to design fittings to allow
any half-arsed cowboy to fit them any way they like). You might equally
ask why domestic 13A plug & socket connectors aren't made so that they
shield the connectors at both ends, so if some dickhead decides to wire
the supply up to a 13A *plug* it doesn't kill anyone.

Like they do for high power loudspeaker stacks with "Speakon" connectors.



--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html