IMPROVEMENTS IN COMPOUND STEAM ENGINES
Year: 1885

page_text: I, HENRY JAMES HOGG KING of Newmarket near Stroud, Gloucestershire'
Engineer do hereby declare the nature of my invention for IMPROVEMENTS IN
COMPOUND STEAM ENGINES to be as follows:-
This Invention relates to Improvements in Compound Steam Engines, and its
objects are to economize room reduce friction, and avoid a dead centre, with a
single crank This allows the Engine to start in any position, and gives a continuous
acting power on the crank pin during the whole of the stroke To effect these
objects I make the connecting rod at the cylinder end of the Engine like an Lor T
and place the centres of the cylinders on the same aproximate plane as that
described by the crank. I also prefer to place the centre of the crank shaft between
the centre lines of the 2 cylinders by which arrangement I reduce the friction on
the slide bars to a minimum, and in working out the details of the Engine it also
gives advantages-In adapting these Improvements to an Horizontal Engine
prefer to place the Low pressure cylinder, at the bottom and the High pressure
cylinder above it, with the centre lines of the cylinders parallel to each other.
I then couple the piston rod of the low pressure cylinder to the connecting rod at
the knee of the L thus its power is transmitted to the crank in the ordinary way,
but the High Pressure piston rod is connected to the short arm of the L near the
end, either with or without a short coupling rod or link Thus, the connecting rod
forms a bell crank; and when the Low pressure cylinder is on its dead centre the
High Pressure is acting to turn the crank round.
A modification of these Improvements consists in making the connecting rod
with T ends and coupling each of the pistons to each end of the T. In condensing
Engines the air pump and condensor can be placed in any convenient position, but
I prefer to drive it direct from the crosshead and place it between the slide bars
and crank.
}

page_text: •
I HENRY JAMES HOGG KING of Newmarket near Stroud, Gloucestershire
Engineer do hereby declare the nature of my invention for IMPROVEMENTS IN
COMPOUND STEAM ENGINES and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement:-
This Invention relates to Improvements in Compound Steam Engines, and its
objects are to Economise Room, Reduce Friction and avoid a Dead Centre, with a
Single Crank, it also effects a considerable saving of steam over ordinary Compound
Engines and is very accessable for Lubrication, & cleaning, and is very readily
taken to pieces for repairs-Having no dead centre the Engine can be started by
Steam in any position of the crank, and as there is a continuous acting.power.on
the crank pin the motion is much steadier than in the ordinary single crank
compound Engine.
:
To effect these objects, I make the connecting Rod at the cylinder end of the
Engine, like an L or Bell crank, or like a T, and place the centres of the cylinders
on the same aproximate plane, as that described by the crank.-I also prefer to
place the centre of the crank shaft on a line between the centre line of the
2 cylinders as by so doing I reduce the friction of the slide bars to a minimum-
And in working out the details of the Engine, I also gain some other advantages-
and in order that my Invention may be properly understood-I have annexed here-
unto, 2 Sheets of Explanatory Drawings. These drawings show the application of
my Improvements to Horizontal Engines, but they are equally applicable to all
other types of Engines with but slight modifications-Figs. 2, 3 & 4 show my
Improvements applied to a Compound Condensing Engine--1. is the High Pressure
Cylinder & 2 the Low Pressure Cylinder. The piston rod 3 of the High Pressure
Cyl is connected to the air pump rod 4 by the steel or mall. casting 5, shown in
plan at Fig. 4. In this casting the pin 6 is fixed, and on it works the link or
connecting Rod 7, which couples it up to the pin 8 on the upper part of the Bell
crank connecting Rod 9. The link 7 moves but slightly on the pin 6, and the
power is transmitted to the upper part of the Bell crank connecting rod in almost
a straight line as the movement of the pin 8 to which the other end of the link is
attached very nearly corresponds with that of the cross head pin 10, which is the
centre on which the connecting Rod turns. 11 is the Low pressure piston rod
which is keyed into the crosshead 12 in the usual way.
It will now be readily understood that when the crank is on its dead centre
at A to the low pressure piston; the high pressure piston, with the Steam admitted
to the cover end of the cylinder, will be exerting a great power, through the
medium of the connecting Rod to drive the crank round in the direction of
the
→ and as the 2 pistons can never be on their dead centre together, they
always-exert a power to continuously turn the crank, and in whatever position the
Engine stops it can always be started again, by steam or the motive power being
applied to the pistons. This can be done by moving the slide valves by hand
or by separate valves or taps, by which Steam can be readily admitted to either
end of the cylinders, the latter arrangement I prefer to use and with these simple

page_text: provisions, the Engine can always be started by the motive power, which is a
great advantage as it saves barring the Engine round by hand or power. Fig. 3
shows the valve gear side of the Engine, with the Air Pump and condensor shown
nearer the cylinders than in Fig. 2. By this arrangement very little more room is
required than with an ordinary. High Pressure Engine. The centre of the. Air
Pump. Barrel is directly over the centre line of the connecting Rod, while the
condensor is at the side to clear the.crank pin..
Passing now to the valve gear it should be noted, that the steam passage 13
.connecting the 2 valve chests together is very short so that almost the full pressure
of Steam from the Exhaust of the High pressure cylinder is found on the low
pressure piston at the beginning of its stroke thus a considerable advantage.is
gained over Engines where the passage or pipe 13 is a long one as must necessarily
be the case in the ordinary Tandem Engine.
It should also be noted that in comparison with the Tandem Engine there is one
gland less in the cylinders and one less in the steam chests, while the pistons are
much more readily withdrawn from the cylinders. It also provides a very simple
& practical way of working the Air pump and reduces the space occupied & the
cost of foundations to a minimum. The pistons being also independant of one
another-in case of a break down in one-the other can be worked independantly.
The valves shown in Fig. 3 are driven by one Eccentric 14-the main valve
being worked by the Eccentric rod 15, & the High Pressure Valve by the rod 16.
The rocking arm 17, working on the pin 18 acts as a guide to the valve
spindle 19.
Fig. 5 Sheet 2 shows the application of my Improvements to a compound non-
condensing Engine In this case the High pressure piston rod is steadied by the
guide 25 which is part of the slide block 26. The piston rods run out into blind
guide tubes fixed to the back of the cylinder covers-The crank shaft it will be
noticed is placed above the centre line of the Low pressure piston rod to reduce the
friction on the slide bars to a minimum, which in any case is less in this class of
Engine than in a Tandem driving the same power as the high pressure cylinder
practically produces no friction on the slide bars, as that which is added by the
H.P. piston to that produced by the L.P. piston on the forward stroke is neutralized
by the deduction to be made on the backward stroke or vice versa.
When it is advantageous to have the crank shaft as high as possible, the
connecting rod can be reversed, and the crank placed as high as the high pressure
piston rod.
Fig. 6 shows the substitution of a T shaped connecting rod for a Bell crank
one In this case the slide blocks 26 are fixed rigidly to the cross head 27; the
cross head also forming a guide to the piston rods and the links 28 & 29 connect
the piston rods with the tails of the connecting rod 30 & 31.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed-I declare what
I claim is :-
1st The use in a compound Engine of a connecting rod substantially as shown
in Fige 2, 3 & 5 or in Fig. 6 which so transmits the power of the 2 pistons to the
crank, that the Engine has no Dead Centre, and can be started in any position of
the crank by the proper admission of the motive power to the cylinders.
2nd Placing the Air Pump (in a compound condensing Engine working on the
principle described in claim 1) on the crank shaft side of the cylinders.
3rd Placing the Air pump in relation to the crank in the positions shown in
Fig 2 & 3 (in a compound condensing Engine working on the principle described
in claim 1) by which arrangement the Air Pump is worked in a direct line from
the piston rod as shown but if the connecting rod is inverted the Low pressure
piston rod would drive the Air pump.
.
4th The arrangement shown in Fig 1 & 2 with the use of the link 7 for
connecting the Air pump; piston rod, and connecting rod together.

page_text: 5th The arrangement of working the Slide Valves substantially as shown in
Fig. 3 (in an Engine working on the principle described in claim 1) by which
means the proper lead is given to both the valves and one Eccentric may be used
for working both valves.
5th Placing the centre of the crank shaft between the centre lines of the 2 piston 5
rods so as to reduce the friction on the slide bars to a minimum, (in an Engine
working on the principle described in claim 1).
+
6th. The use of taps or valves for admitting Steam to the cylinders for starting.
the Engine (in an Engine working on the principle described in claim 1).
7th Making the cross head of the Low pressure cylinder a guide for the High 1
Pressure piston rod as shown in Fig. 5, (in a compound Engine working on the
principle described in claim 1) & in Fig. 6 for both rods.
Dated this third day of Au00e