An Improvement in Starting and Stopping Apparatus for Compound Engines.
Year: 1889

page_text: Date of Application, 19th Dec., 1889
Complete Specification Left, 25th July, 1890-Accepted, 30th Aug., 1890
PROVISIONAL SPECIFICATION.
An Improvement in Starting and Stopping Apparatus for Compound
Engines.
I, ARTHUR HERBERT WALLIS of North Hants Iron Works, Basingstoke, Hampshire
do hereby declare the nature of this invention to be as follows:-
As compound engines are usually arranged, steam after performing work in one
cylinder exhausts therefrom into a reservoir whence it supplies another cylinder at
lower pressure, and this may be repeated three or more times. It is difficult to effect
the stopping and starting of an engine of this kind because in the case of stoppage
although the supply to the high pressure engine may be cut off, the reservoir or
reservoirs go on supplying the low pressure cylinders keeping the engine in motion,
and in the case of starting, although the high pressure cylinder may be supplied, there
is no supply to the low pressure cylinders. My invention relates to means of over-
coming these difficulties which I effect in the following manner. I provide shut off
valves for the several cylinders so arranged that they are simultaneously opened or
closed by one action, and I furnish the reservoir or each reservoir if there are several
of them with a supply pipe governed by a reducing valve so adjusted that the reservoir
is supplied with live steam only when the pressure in. the reservoir is below a certain
minimum sufficient for acting in the low pressure cylinder connected to the
reservoir.
Thus, by the one action I can shut off steam from all the cylinders, so causing
immediate stoppage of the engine, and as the reservoirs are always charged up to the
minimum pressure required, by the one action I admit steam to all the cylinders,
causing the engine to start.
Dated this 10th day of December 1889.
COMPLETE SPECIFICATION.
An Improvement in Starting and Stopping Apparatus for Compound
Engines.
I, ARTHUR HERBERT WALLIS of North Hants Iron Works, Basingstoke, Hampshire
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:—
As compound engines are usually arranged, steam after performing work in one
cylinder, exhausts therefrom into a reservoir whence it supplies another cylinder at
lower pressure, and this may be repeated three or more times. It is difficult to effect
the stopping and starting of an engine of this kind because in the case of stoppage
although the supply to the high pressure cylinder may be cut off, the reservoir or
reservoirs go on supplying the low pressure cylinder or cylinders keeping the engine
in motion, and in the case of starting, although the high pressure cylinder may be
supplied, there is no supply to the low pressure cylinder or cylinders.
My invention relates to means of overcoming these difficulties which I effect in the
following manner :-
I provide shut off valves for the slide jackets of the several gylinders so arranged
that they are simultaneously opened or closed by one action, and 1 furnish the reservoir
or each reservoir if there are several of them with a supply pipe governed by a reducing
valve so adjusted that the reservoir is supplied with live steam only when the pressure
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in the reservoir is below a certain minimum sufficient for acting in the low pressure
cylinder connected to the reservoir.
Thus by the one action of closing the valvesI can shut offsteam from all the cylinders,
so causing immediate stoppage of the engine; and, as the reservoirs are always
during working charged up to the minimum pressure required by the one action of
opening the valves, I admit steam to all the cylinders, causing the engine
to start.
Figure 1 of the accompanying drawings is a part side view, aud
Figure 2 is an end view of the cylinders of a compound two cylinder engine to
which my invention is applied.
Figure 3 is a transverse section of the cylinders through the high pressure slide
valve, aud
Figure 4 is a similar section through the low pressure slide valve.
Figures 5 and 6 are vertical sections on planes at right angles to one another
and
Figure 7 is a sectional plan, shewing on an enlarged scale a convenient form of
reducing valve which I employ.
I provide sluice valves A and B or other suitable stop valves by which I can
simultaneously cut off the steam supply to the high and the low pressure cylinders
respectively, the stems of these valves being both connected to arms of one rocking
shaft C, so that on moving this rocking shaft by a lever D, both valves A and B are
simultaneously closed or opened for the purpose of stopping or starting the engine.
I provide a reducing valve E (Figure 3) which may be of the construction shewn
in Figures 5 6 and 7. It has two valves on the stem of a pistou Q which is pressed
down by a loaded lever so that when these valves are unseated there is communication
between two branches F and G. The branch F communicates with the space H of
the high pressure slide jacket which space when the valve A is open is supplied with
steam direct from the boiler by the pipe P. The branch G communicates with the
reservoir space R which receives the exhaust from the high pressure cylinder and
which, when the valve B is open, supplies the space L of the low pressure slide
jacket.
The apparatus operates as follows:-
By moving in one direction the lever D, both the valves A and B are closed cutting
off steam from the slide jackets of both cylinders, and the engine is stopped.
When it is desired to start again, both the valves A and B are simultaneously
opened by moving the lever D in the opposite direction, and if the reservoir R should
at that time contain steam at pressure sufficient for the low pressure cylinder, the engine
is started. But should the pressure in R have become too low or tended to become too
low, then the reducing valve E operates admitting steam from the slide jacket H to
the reservoir R thus maintaining in R the pressure determined by the adjustment of
the reducing valve E. This pressure is adjusted by proportioning the load on the
lever to the area of the piston Q, so that the valves attached to that piston open only
when the pressure upwards on the piston Q, which is the pressure in R is less than
the load on the piston downwards. Obviously instead of a weight the piston Q
might be loaded by a spring or by the pressure on another piston connected
to it.
I prefer to provide in addition to the reducing valve E a check valve M
closing a passage from F to G so that when, although steam is shut off, the momentum
of the fly wheel continues the movement of the engine causing a pumping action in
the cylinders, steam can pass from the reservoir R to the high pressure slide jacket thus
maintaining the high pressure slide valve in equilibrium and so preventing it from
being forced away from the facing. Although I have shewn my invention applied to
a compound engine having only two cylinders, obviously when there is a greater
number of cylinders, the apparatus may be repeated for each successive pair. For
example, when there are three cylinders with a reservoir between the first and second,
and a reservoir between the second and third, I provide three shut off valves, one for
pach cylinder, connected to one lever, and two reducing valves, one between the slidę

page_text: jacket of the first cylinder and the reservoir which its exhaust supplies, and one
between the slide jacket of the second cylinder and the reservoir supplied by its
exhaust. The reducing valve in each case operates automatically supplying the reservoir
with steam when steam is required.
When such automatic action is not desired, each reservoir may be connected by a
branch pipe to the boiler or maiu steam pipe, with a cock or valve in the branch,
by opening which the reservoir can be supplied with steam to the pressure
required.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
In combination with the cylinders and intermediate reservoirs of a compound engine,
shut off valves, one for each cylinder, connected to one lever or motor by which they
are simultaneously opened or closed, and an adjustable reducing valve in a communi-
cation from the supply of each cylinder to the reservoir supplied by its exhaust,
substantially as and for the purpose herein set forth.
DELL 1. T.... 1900
ABEL & IMRAY,
Agents for the Applicunt.