IMPROVEMENTS IN LOCOMOTIVE AND TRACTION ENGINES WORKED BY COMPRESSED AIR OR OTHER ELASTIC FLUID UNDER HIGH PRESSURE
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by George Daniel Bishopp at the Office
of the Commissioners of Patents on the 26th October 1880.
GEORGE DANIEL BISHOPP, of No. 3, St. Charles Square, North Kensington, in
the County of Middlesex, Civil Engineer. "IMPROVEMENTS IN LOCOMOTIVE AND
TRACTION ENGINES WORKED BY COMPRESSED AIR OR OTHER ELASTIC FLUID
UNDER HIGH PRESSURE,"
My Invention relates to that part of a locomotive or traction engine which in
locomotives worked by steam is called the "boiler," but which in engines worked
by compressed air is called the "reservoir," and I construct that part in such a
manner that it furnishes a mode or method of economising and using to great
advantage the pressure of the compressed air or elastic fluid.
In describing my Invention it is to be understood that when I use the word
"air" I mean that word-to include "other elastic fluids," and when I use the word
"locomotive "I mean that word to include "traction engines" and other road
locomotives,
I construct each locomotive engine with two or more reservoirs, and I connect
each reservoir by a pipe or otherwise to a feed pipe leading to the regulator, and I
fit to each reservoir a valve or cock, so that all or any of the reservoirs can be
opened to or shut off from the said feed pipe and to or from each other. Each
reservoir has a pressure gauge fitted to it.
When more reservoirs are required than can be fixed on the same frame as the
cylinders and other parts of the engine, I fix the rest of the reservoirs on a separate
frame and wheels forming a tender, and I connect those reservoirs to the feed pipe
by a jointed pipe or pipes.
I will now describe the method of using the above described reservoirs and valves
both on the engine and tender, first stating that the greater the number of reservoirs
used the greater the advantage and economy will be, and I will therefore describe
the method of using several reservoirs, as follows :—
When first starting the locomotive on its journey, the reservoirs are to be charged
with air compressed to the highest pressure intended to be used, and one reservoir
only is to be opened to the feed pipe. When the pressure in that reservoir (which
I will call reservoir No. 1) has become so far reduced that it is no longer sufficiently
effective, the valve of that reservoir is to be closed, and the valve of another
reservoir (which I will call No. 2) is to be opened to the feed pipe. When the

page_text: pressure in No. 2 reservoir becomes so far reduced that it is no longer sufficiently
effective, then its valve is to be closed, and the valve of No. 3 reservoir is to be
opened to the feed' pipe; and so of the rest of the reservoirs. Whenever in passing
over a less gradient, or a level, or a down gradient, the reservoir then in use has
more pressure in it than is necessary, the valve of that reservoir is to be shut, and
the valve of a reservoir which has been used previously is to be opened, provided
there be a reservoir having less pressure in it, and that that pressure is sufficient to
keep up the required speed. In this way the compressed air will be economised,
not having to expand so much before entering the cylinders, as it does when the
pressure in a reservoir is much greater than the pressure required in the cylinders.
When a locomotive or traction engine is fitted with several of these reservoirs,
one reservoir should always be kept unused as long as possible, so as always to
have some air at high pressure kept in reserve for emergencies.