Improvements in Compound Locomotive and Tramway Engines.
Year: 1886

page_text: Date of Application, 3rd Aug., 1886
Complete Left, 2nd-May, 1887.
Complete Accepted, 3rd June, 1887.
Improvements in Compound Locomotive and Tramway Engines.
I RICHARD CLERE PARSONS of Airedale Foundry, Leeds, in the County of York,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to means of effecting better distribution of the working fluid
in relation to the high and the low pressure cylinders of compound locomotive and
tramway engines, and of facilitating the starting of such engines.
For this purpose I connect the sliding blocks of the link motions to arms of
different lengths projecting from one weigh shaft, the longer arm being connected to
the block for the low pressure cylinder so that a movement of the weigh shaft gives
a longer shift to the low pressure than to the high pressure block, and consequently
the low pressure slide valve is made to give a longer admission of the working fluid to
the low than to the high pressure cylinder. In the exhaust passage of the high
pressure cylinder I provide an escape valve connected to a piston. On admitting
steam to act on this piston the valve is opened allowing free escape for the exhaust,
without subjecting it to the back pressure in the low pressure cylinder, and I thus
obtain for the time the full effect of the high pressure fluid on the piston of the high
pressure cylinder.

page_text: Improvements in Compound Locomotive and Tramway Engines...
I, RICHARD CLERE PARSONS of Airedale Foundry, Leeds in the County of York,
Engineer, do hereby declare the nature of this invention, and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement :—
My invention has for its object to render the starting of compound locomotive and
tramway engines more certain and rapid, and it consists in the employment of an
improved valve apparatus for causing the exhaust steam from the high pressure
cylinder to pass directly into the atmosphere on starting the engine, instead of into
the low pressure cylinder, so as to relieve the high pressure piston from the back
pressure due to the latter.
For this purpose I provide in the exhaust passage from the high pressure to the low
pressure cylinder an escape valve connected to a piston in a cylinder so arranged that
on admitting steam behind the piston, the latter moves the valve so as to cause it to
close the communication between the high and low pressure cylinders and establish a
communication between the former and the atmosphere.
The arrangement of apparatus which I prefer to employ for this purpose is shown in
longitudinal and cross sections at figs. 1 and 2 of the accompanying drawings. C is
the exhaust passage from the high pressure cylinder, and B is the supply passage
leading to the low pressure cylinder, between these is arranged a cylindrical chamber E
in which is a passage J leading to the atmosphere and a slide valve H connected to a
piston G, which valve when in the position shewn, in which it is ordinarily maintained
by a helical spring K acting on an external extension of the piston's rod, leave the
communication between high and low pressure cylinders free for ordinary compound
working.
When it is desired to put the high pressure exhaust in communication with the
atmosphere, steam is admitted behind the piston G, through a pipe F leading from the
engine boiler and provided with a suitable cock, valve or slide accessible to the driver,
whereby the piston will be forced forward against the action of the spring causing the
valve H to close the communication between C and B and establish the communication
between Cand J, so that the exhaust steam from C will escape into the atmosphere.
After the engine is started the cock, valve, or slide, on the steampipe F is
moved by the driver so as to put the space behind the piston G in communication
with a passage leading to the atmosphere whereupon the spring K will move the slide
valve H back into the position shewn, and the engine will then work with the
ordinary compound action.
In combination with the above described arrangement may be used a device shewn
in longitudinal and cross sections at figs. 3 and 4, whereby full pressure steam is also
admitted to the low pressure cylinder when its communication with the high pressure
cylinder is cut off as above described. A is a chamber communicating at I with the

page_text: steam boiler, and D with the chamber E in front of the piston-G, at F with the spac
behind the piston and at L with the atmosphere.
These passages are governed by a slide valve M in such manner that for ordinary
compound working the slide remains in the position shewn, in which passage D ís
closed and passage F communicates with the atmosphere through L.
For starting the engine the slide M is moved by the driver so as to uncover both
the passages D and F whereupon steam from I will pass simultaneously through D
into the low pressure cylinder and through F behind piston G, moving the slide valve H
so as to put the high pressure exhaust in communication with the atmosphere.
Having now particularly described and ascertained the nature of this invention and
in what manner the same is to be performed I declare that what I claim is :-
In a compound locomotive or tramway engine the use in connection with the
exhaust passage leading from the high pressure to the low pressure cylinder, of a valve
so arranged in combination with a piston, that on admitting fluid pressure behind the
piston the valve is moved so as to cut off the communication between the high and low
pressure cylinders and establish a communication between the high pressure cylinder
and a passage leading to the atmosphere substantially as and for the purposes herein
described.
ABEL & IMRAY,
Agents for the Applicant.