[modeleng] Re: Flat valves
- From: "Jesse Livingston" <fernj1@xxxxxxxxxxxxx>
- To: <modeleng@xxxxxxxxxxxxx>
- Date: Tue, 30 Oct 2007 05:36:30 -0500
Peter,
I expect that increased heat and pressure against the valve ports, even with
"balanced valves" made lubrication difficult which then caused excessive
wear to the valve faces and increased wear on the linkage components. In
the case of Mallet type locomotives, at least over in the USA, piston valves
were used on the HP cylinders and flat "D" valves on the LP cylinders.
Jesse, in cooler, but not cold W. Tennessee
When the 12 inch to the foot scale started using superheated steam, the
books tell us that lubrication problems meant flat valves were
unsatisfactory, and piston valves were needed. Why? I can see that it's
easier to get a given port openeing with a piston valve than a flat valve
in a given size, but I don't understand why lubrication makes the piston
valave more desirable.
Peter Chadwick
Swindon
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