Improvements in Compound and Multiple-expansion Steam Engines.
Year: 1899

page_text: Improvements in Compound and Multiple-expansion Steam Engines.
I, WILFRED ADAM ASHWORTH, of Ashmeadows, Bury, in the County of
Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows:-
:-
My object is to form a compound or multiple expansion engine, which shall
be more compact, economical and simple than those at present in use.
I accomplish this by coupling together two compound cylinders, (each con-
taining two pistons, one high and the other low pressure, preferably coupled
and having the same length of stroke,) by means of a suitable valve chamber,
with a double valve action, (one for low and the other for high pressure,) prefer-
ably keyed to the same valve rod and working together for the same length of
stroke from the same eccentric,) placed between them.
By placing one of the compound cylinders at a lower level than the other,
I am able to make all the ports straight and with very small clearance and all
selfdraining, and owing to the larger size of the valve chambers and other
details of the construction I obtain both a better balance of the working parts,
thus counterbalancing their weight, and I am able to regulate the graduated
pressure of the steam on both low pressure and high pressure pistons on the
upstroke.
Al 5
Improvements in Compound and Multiple-expansion Steam Engines.
I, WILFRED ADAM ASHWORTH, of Ashmeadows, Bury, in the County of
Lancaster, 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 object is to form a compound or multiple expansion engine, which shall
be more compact, economical and simple than those at present in use.
I accomplish this by coupling together two compound cylinders, by means of
a suitable valve chamber placed between them, in such a manner, that one of
the compound cylinders is at a lower level than the other. Each compound
[Price 8d.]

page_text: cylinder contains two pistons, one for high, and one for low, pressure, preferably
coupled and having the same length of stroke.
The connecting valve chamber, has a double valve action, one for low, and
one for high pressure, preferably keyed to the same valve rod, and working
together, for the same length of stroke, from the same eccentric.
By placing one of the compound cylinders at a lower level than the other, I
am able to make all the valve ports straight, and with very small clearance,
and all self-draining, and owing to the large size of the valve chambers and
other details of my improved construction, I obtain, not only a better balance
of working parts, but also a graduated resisting pressure of steam on the combined
pistons during the upstroke. It will be understood that in the case of a
triple expansion, three pistons and three valve actions are required.
In order that the foregoing may be better understood I send herewith a
sheet of drawings in which is shown a cross section of a part of a compound
expansion engine constructed with my improvements.
Referring to this, a and b indicate two compound cylinders constructed as
described, coupled together, and enclosed, by large valve, chamber and receiver c.
Each compound cylinder contains two pistons, one in each case, (d and e.)
being for high pressure steam, and one in each case, (f and g,) being for low
pressure steam each pair, d and f, and e and g, being coupled by the same
piston rod h and i respectively and so working the same length of stroke, both
low pressure cylinders being open at the top to the large connecting valve
chamber c, which contains two valves, one for high pressure and one. for
low pressure steam coupled together by one valve rod m and working with the
same length of stroke.
When the engine is in work the central valve chamber and receiver c is
filled with low pressure steam which is admitted by valve being the exhaust
of high pressure cylinders d and e. This low pressure steam is used in the
downstroke of the low pressure pistons f and g, and is also admitted by low
pressure valve 7 below them in turn for half (or other desired portion) of their
upstroke, thus balancing the back pressure of the low pressure steam, in
chamber c, on the upper side of the low pressure pistons for half the upstroke
and then allowing it (the back pressure) to become a gradually increasing
pressure as the low pressure steam below the pistons expands and 1: force.
Among other minor advantages of my construction may also be mentioned,
that the cylinders are practically steamjacketed by the receiver e and that the
stuffing-boxes are never subjected to the action of the high pressure steam.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1st. The combined apparatus, substantially as described and shown herein-
before and in the accompanying drawings, for the purpose set forth.
2nd. In compound and multiple expansion steam engines coupling together
two or more compound or multiple cylinders by means of a large central valve
chamber, substantially as described and shown hereinbefore and in the accom-
panying drawings, for the purpose set forth.
3rd. In compound and multiple expansion steam engines, coupling together two
compound or multiple cylinders by means of a large central valve chamber in
such a manner that one compound or multiple cylinder is at a lower level than
the other, substantially as described and shown hereinbefore and in the accom-
panying drawings for the purposes set forth.
Dated this 23rd day of November 1899
JOHN HENRY TOPHAM,
7, South Corridor, Royal Exchange, Manchester, Agent to Applicant.