Improvements in Steam Engines and like Motors.
Year: 1889

page_text: Dat: of Application, 20th Aug., 1889
Complete Specification Left, 19th May, 1890-Accepted, 21st June, 1890
PROVISIONAL SPECIFICATION.
Improvements in Steam Engines and like Motors.
We, PETER WILLIAM WILLANS and MARK HEATON ROBINSON of Ferry Works,
Thames Ditton, in the County of Surrey, Engineers, do hereby declare the nature
of this Invention to be as follows:-
This invention has for its object improvements in steam engines and like motors.
We mount a high pressure piston and a low pressure piston on the same piston rod
which by a connecting rod drives a crank.
Preferably the high pressure piston is above and the crank below and the low
pressure piston is between the two. The high pressure steam works more or less
expansively in the cylinder space above the high pressure piston; it is then exhausted
into a chamber between the pistons where it exerts a continuous pressure subject to
the fluctuation in the receiver on the upper surface of the low pressure piston so that
the connecting rod constantly thrusts upon the crank, the engine being single acting.
Finally the steam is drawn out from this chamber and again worked more or less
expansively in the cylinder space beneath the low pressure piston. The steam is then
allowed to escape either to a condenser or into the atmosphere.
The passage of the steam may be directed by a single valve or line of valves, which
may be either external or contained within a hollow piston rod. The piston rod may
carry a small piston serving as a valve to cut off steam from the high pressure piston;
the said piston valve working in a cylinder above the high pressure cylinder and
travelling over ports in its side.
The arrangements described in the Specification of Scott's Patent No. 15858 in the
year 1886 are applicable to control the cut off of the steam passing from the inter-
mediate chamber to the under side of the low pressure piston.
The exhaust from the high pressure cylinder we obtain partly by causing the piston
to travel over ports in the side of the cylinder; towards the end of its stroke these
ports also will give free passage to water in case it is present.
To provide against damage from water beneath the low pressure piston we do not
connect this piston rigidly with the crank but so that the crank can complete its
rotation even if the piston fails to reach the end of the stroke. This provision may
be made in various ways but the most simple is to connect the lower brass to the head
of the connecting rod by the aid of springs.
Dated this 20th day of A 100A
CARPMAEL & Co.,
A genta
COMPLETE SPECIFICATION.
Improvements in Steam Engines and like Motors.
We, PETER WILLIAM WILLANS and MARK HEATON ROBINSON of Ferry Works,
Thames Ditton, in the County of Surrey, Engineers, 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:—
This Invention has for its object improvements in steam engines and like motors
and applies more especially to steam or vapour engines in which there is a high
pressure piston and a low pressure piston on the same rod arranged vertically
over the crank and in which the piston rod acting thro the connecting rod
should thrust constantly (although with varying force) upon the
In such engines water or liquid resulting from condens...
.
rank.
is liable to lodge

page_text: in the low pressure cylinder beneath the piston and injury to the machine may
result.
To provide against damage from water beneath the low pressure piston we do
not connect this piston rigidly with the crank.but so that the crank can complete
its rotation even if the piston fails to reach the end of the stroke. This provision
may be made in various ways but the most simple is to connect the lower brass
to the head of the connecting rod by the aid of springs.
In order that our Invention may be fully understood and readily carried into
effect we will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is an elevation for the most part in section of an engine in which our
Invention is applied.
Figure 2 is a section on the line 2-2 in Figure 1.
a is the high pressure cylinder and is the low pressure cylinder, their pistons are
on the same rod c, the head of the rod works in a guide at d and by a connecting rod e
is coupled with a crank on a shaft f. 9 is the valve or series of valves receiving
motion from an eccentric on the crank shaft.
The valve admits steam first on to the top of the high pressure piston then allows it
to pass from the high pressure cylinder into a receiver h between the two cylinders
and open to the upper side of the low pressure piston, afterwards the valve allows the
steam to pass from the receiver to the under side of the low pressure piston and finally
to pass from the low pressure cylinder and out of the engine by the exhaust passage i.
There is always a preponderating pressure downwards upon the pistons. This arrange-
ment of cylinders, pistons and valves is described in our Provisional Specification but
we make no claim for it, as we find that in this part of our Invention we have been
anticipated by a Patent granted on an application of earlier date.
To prevent damage from the accumulation of water beneath the low pressure piston
the lower brass e¹ is not rigidly fixed in the connecting rod head but is supported by
a spring hence if the piston rod should fail to make the full stroke the crank
is nevertheless able to rotate without serious check the spring yielding to permit it to
do so.
The spring e² surrounds a stem formed on the lower brass and this stem passes
through a cross bar e which is supported by the bolts e*. These bolts connect the
cross bar with the head of the connecting rod and also serve as guides on which the
brass or brasses are able to slide.
Having now particularly described and ascertained the nature of our said Inven-
tion and in what manner the same is to be performed we declare that what we
claim is:―
Providing against damage from water or Iquid beneath the low pressure piston of
a compound engine in which the connecting.od should constantly thrust upon the
crank, by means of an elastic connection between the pistons and the crank substan-
tially as described.
Dated this 17th day of May 1890.
P. W. WILLANS.
MARK H. ROBINSON.