On Tue, 6 Jan 2004 10:21:33 -0500, Ned Simmons wrote:
In article ,
says...

This is a clear case where the *absence* of a
regulator wastes energy. It is in fact the *usual* case.

This is like saying there is no loss in a shunt regulator
because it can be used to supply the proper voltage to a
device that may self destruct or draw excessive current in
the absence of the regulator. (Just had to work in an
electrical analogy.)

No! It is not even remotely similar. A shunt regulator accepts
*every bit of energy the source is capable of supplying* at any
given moment, passes part of it to the load, and converts the
rest of it to heat in the shunt resistance.


All right. Yet another bad electrical analogy. I oughta
know better by now.

An air regulator valves *just enough* energy from the tank to
satisfy the load at any given moment. No more. The rest
*remains in the tank*.

Then please respond to my previous post and explain how
you're going to determine whether the water removed from a
reservoir, or the air released from a pressurized tank, was
used to do mechanical work, or simply released to the
environment. If you're correct it will be possible to tell
without looking beyond the boundaries of the reservoir or
tank.

If I'm correct, and I am, you have to *look* downstream to
see whether the water or air released was usefully employed.
There's no way to determine that from inside the tank.

Fortunately, a regulator is a feedback device, it does "look"
downstream to see what the load demand is, and adjusts
itself to just supply that demand. In other words, it looks
at the downstream pressure and adjusts the flow just enough
to maintain the pressure at the set value. It lets no more air
through than is required to supply the energy the load
demands.

Gary