The Aster C&S Mogul has two. One on the boiler and one in the cab. Both set
to 4 kg/cm2. They are stainless steel ball and spring assemblies designed to
prevent boiler pressures from rising above this point, but the boiler itself
is tested to 7 kg/cm2 at the factory. For modelers, one is good, two is
better.
Normal operating pressure for the boiler is between 2-4 kg/cm2 depending on
the load of your consist.
This figures out to about 2/3 - 3/4 of the actual operating pressure of the
prototype.
One thing that doesn't seem to change AS DRASTICALLY, in scale steam
modeling, is steam pressure itself. Your aren't even going to move the Loco
with 3lbs of steam pressure against a piston that is only 12mm in diameter.
But when you consider the boiler volume of the prototype with the model,
that's close to what the pressure would scale to if it worked that way. But
it doesn't.
Alas, boilers are boilers. Regardless of scale. And require rigorous
attestation to detail for safety reasons.
Otherwise, one is just "blowing smoke". (Or "hot air" and water from a leaky
one.)
(Smile)
Lee
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On
Behalf Of Gary Broeder
Sent: Friday, July 10, 2893 1:44 PM
To: Multiple recipients of sslivesteam
Subject: RE: Aster Safety Valves
>
>Does anyone know why Aster always uses two safety valves on their engines?
>
>Don Plasterer
Don,
Aster does not always use two safety valves. The Pannier tank and the early
0-6-0 tank and the Grasshopper
have only one. PErhaps there were others but these were close at hand.
GaryB
