IMPROVEMENTS IN THE CONSTRUCTION OF RECIPROCATING STEAM ENGINES
Year: 1872

page_text: LETTERS PATENT to Thomas Williamson, of Stalybridge, in the
County of Lancaster, and William Walker, of Newton Moor, in
the County of Chester, for the Invention of "IMPROVEMENTS IN THE
CONSTRUCTION OF RECIPROCATING STEAM ENGINES."
PROVISIONAL SPECIFICATION left by the said Thomas Williamson
and William Walker at the Office of the Commissioners of Patents,
with their Petition, on the 24th December 1872.
We, THOMAS WILLIAMSON, of Stalybridge, in the County of Lancaster,
and WILLIAM WALKER, of Newton Moor, in the County of Chester, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
CONSTRUCTION OF RECIPROCATING STEAM ENGINES," to be as follows:-
This Invention relates to that class of steam engine used for pumping,
blowing, compressing air, and other similar purposes where a recipro-
Ocating motion only is required.
The steam cylinder is constructed on the ordinary three ported
principle, having a circular valve chamber, and fitted with piston valve
to correspond. The main piston being slightly longer than the stroke,

page_text: is simply made to perform the functions of an eduction valve, and to
operate in reversing the said piston at or near each end of the stroke
alternately.
The piston valve is made by preference in one piece, having closed
ends, whereby steam is made to expand or act upon either end when-
ever the opposite end is placed in direct communication with the main
exhaust passage.
An extra steam passage is formed near each end and at opposite
sides of the valve chamber, each passage leading to the centre of
the steam cylinder, but on opposite sides of its centre line or axis.
The steam piston proper has a pocket or recess formed near each end
and at opposite sides, these pockets communicating with opposite ends
of the steam cylinder by means of longitudinal thoroughfares in the
interior of the main piston.
The piston valve in one modification of the arrangement is not fitted
with any metallic or other packing, and naturally allows a slight
leakage of steam to pass its ends, the steam thus passing being
imprisoned or shut in whenever either end closes its own exhaust port,.
forms a cushion to check the motion of said valve.
The thoroughfares before named are so constructed that immediately
after the piston valve has closed its own exhaust port, afterwards that
exhaust port is charged with "live steam" from the main cylinder,
and upon the liberation of steam at the other end of valve box this
"live steam" along with that which has been previously shut in
expands and serves to force the valve over.
In another modification the piston valve may be fitted perfectly
steam-tight by the application of metallic rings or other equivalent
means; and when this is the case an additional miniature steam
passage is formed at each end of the valve box on its lower side.
These miniature ports are so arranged that either of them (as the case
may be) is opened simultaneously with the closing of the exhaust port
at the same end of the valve box leading to the interior of the main
piston as before named; the steam thus passing through the miniature
ports from the inside to the outer end of the piston valve serves to act as
a cushion, and produce precisely similar results to the method previously
described.

page_text: The principle upon which the piston valve is reversed in these two
instances absolutely depends upon the motion of the main piston;
whenever either of the pockets formed on its sides as before stated shall
pass over or uncover to the main exhaust one of the central thorough-
fares arranged on the corresponding side of the steam cylinder.
Each end of the valve chamber is fitted with starting spindles in order
to move the piston valve in either direction; these spindles when not
required are pressed outwards against conical seatings by the pressure of
the steam within the valve box, and are at rest when the mechanism is
in operation.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Williamson and William Walker in the
Great Seal Patent Office on the 17th June 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, We, THOMAS
WILLIAMSON, of Stalybridge, in the County of Lancaster, and WILLIAM
WALKER, of Newton Moor, in the County of Chester, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Lotters Patent, bearing date the Twenty-fourth day of December, in
the year of our Lord One thousand eight hundred and seventy-two, in
the thirty-sixth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto us, the said Thomas Williamson and William
Walker, Her special license that we, the said Thomas Williamson
and William Walker, our executors, administrators, and assigns, or
such others as we, the said Thomas Williamson and William Walker,
our executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE CONSTRUCTION OF RECIPROCATING STEAM ENGINES," upon
the condition (amongst others) that we, the said Thomas Williamson
and William Walker, by an instrument in writing under our hands

page_text: and seals, or under the hand and seal of one of us, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that we, the said Thomas Williamson and William
Walker, do hereby declare the nature of our said Invention, and in what
manner the same is to be performed, to be particularly described and
ascertained in and by the following statement and the accompanying
Drawings (that is to say) :-
Our Invention is illustrated by the accompanying Drawings, Figure 1
being a longitudinal section; Figure 2 a cross section at A-B, Figure 1;
and Figure 3 a cross section at C-D, Figure 1; these three Figures.
illustrating one modification of our Invention.
Figure 4 is a longitudinal section, and Figure 5 a cross section at
A-B, Figure 4, illustrating the other modification of our Invention.
The Invention relates to that class of steam engine used for pumping,
blowing, compressing, and other similar purposes where a reciprocating
motion only is required.
The steam cylinder (a) is constructed upon the ordinary three ported :
principle, having a circular valve chamber or chest (6) fitted with a
piston valve (c) to correspond, the steam entering the cavity (c¹) in the
valve, and by a slight leakage arranged in the fitting of the valve the
steam can also pass to the spaces 6¹ at each end of the valve in the valve
chest.
The main or piston proper (d) is in one modification (Figure 1) formed
by two pistons connected by three bars (d), in the other modification
(Figure 4) it is a cylinder. The piston (d) is made slightly longer than
the stroke, and so as to perform the functions of an eduction valve, and
thus operate in reversing the circular or piston valve (c) and consequently
its own movement at or near the end of its stroke alternately.
The piston valve (c) is made, by preference, in one piece having
closed ends, whereby steam is made to expand or act upon either end
whenever the space (6¹) at the opposite end of the valve is placed in
direct communication with the main exhaust passage (a*).
An extra exhaust steam port and passage (e) is formed near each end
of the valve chest, each passage (e) leading to the centre of the steam

page_text: cylinder, one passing on one side, the other on the other side of the centre
line of the cylinder.
The steam piston (d) has a pocket or recess (d²) formed near each end
to correspond with the passages (e) above mentioned. These pockets (d²)
communicate with the opposite ends of the steam cylinder (a) by means
of longitudinal passages (d³) formed in the interior, or in the parts
connecting the two ends forming the piston (d).
The piston valve in one modification (Figure 1) is not fitted with any
metallic or other packing, and consequently allows, as before stated, a
slight leakage of steam to pass to the spaces (6¹) in the valve chest at
its ends, and when one of these spaces is open to the exhaust side of the
piston (d) the valve (c) in moving will close the exhaust port (e) on that
side, and the residue of the steam will thus be imprisoned or shut in,
and will form a cushion to check the movement of the valve and prevent
it from striking against the end of the valve chest.
The passages (e) before named are so arranged that immediately after
the piston valve (c) has closed its own exhaust port (e) on the side to
which it has been moved, the said passage (e) leading to that port will
be filled with "live" steam from the main cylinder (a) through the
passage (³) in the piston, and such "live" steam will be left shut up in
the said passage (e) by the piston when it begins to reverse, and the
steam thus left shut up and the residue left in the space (6¹) at the end
of the valve, and the leakage will expand and reverse the piston valve (c)
when the steam is exhaused from the space (6¹) in the valve chest at the
opposite end of the valve, as before explained.
In another modification (see Figure 4) the piston part of the valve (c) is
fitted perfectly steam tight by the application of metallic rings or other
equivalent means, and when this is the case an additional miniature
steam passage (f) is formed at each end of its valve box at its lower
side. These miniature ports are so arranged that either of them (as the
case may be) is opened simultaneously with the closing of the main
port (a) to the exhaust at the same end of the valve box. The steam
admitted through the miniature ports (f) serves as a cushion, and to
reverse the valve by expansion, as explained in reference to Figure 1.
The principle upon which the piston valve (c) is reversed in both
modifications above described, depends absolutely upon the motion of
the piston (d), as at the moment either of the pockets (d) formed on

page_text: its sides (as before explained) comes over or uncovers the opening of
the passage (e,) a communication is formed with the exhaust which will
cause the piston valve (c) to reverse accordingly. 9 is a set screw, the
end of which passes through the cylinder and fits a groove formed in the
piston, which is thus prevented from rotating, and the pockets in it are
thus kept in a line with the passages c. Set screws i are employed in
like manner to keep the valves from turning. A tap may be fixed in
the mid-length of the cylinder (a), so that the cavity or space between
the two ends of the piston and the cylinder may be opened to the
atmosphere, when required.
At each end of the valve chest a valve spindle h is fitted to slide (see
Figure 4), so that the valve (c) can be pushed to the proper position
when the engine is to be started. The inner ends of these spindles
are formed with cones to fit scatings on the ends of the valve chest,
so that when not required the spindles will be forced outwards by the 1
steam, and the cones being pressed against the seatings keep the spindles
steam tight.
From the previous description it will be seen that our improved
engine has practically only two moving parts, and from the entire
absence of metallic percussion a silent action is obtained.
We have now particularly described the nature of our Invention, and
the mode of carrying it into effect, and claim as our Invention the
arrangement and combination of the piston (d) and piston valve (c) and
their mode of action, substantially as herein-before described and illus.
trated by the accompanying Drawings.
In witness whereof, we, the said Thomas Williamson and William
Walker, have hercunto set our hands and seals, this Eleventh day
of June, in the year of our Lord One thousand eight hundred
and seventy-three.
2
2
THOMAS WILLIAMSON. (L.S.)
WILLIAM WALKER.
(L.S.)