In- PROVEMENTS IN STEAM ENGINES
Year: 1875

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
in the County of Middlesex, Gentleman, for the Invention of "In-
PROVEMENTS IN STEAM ENGINES.”—A communication from abroad by
Farrelly Alden and Abram Alexander, both of Pittsburg, in the
State of Pennsylvania, United States of America.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition,
on the 26th May 1875.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
5 of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN STEAM ENGINES," a communication to
me from abroad by Farrelly Alden and Abram Alexander, both of
Pittsburg, in the State of Pennsylvania, United States of America, to
be as follows:-

page_text: stationary, locomotive, portable, and marine purposes, and consists in
the employment of two steam cylinders in combination with one or more
auxiliary cylinders, by preference arranged in a line therewith, into
which the steam from the steam cylinders exhausts alternately.
The whole of the cylinders are provided with the necessary ports and t
valves for the admission and exit of the steam, and the pistons of the
steam cylinders, as well as that of the auxiliary cylinder, are carried
upon one and the same piston rod, and so arranged as that the two
steam pistons operate alternately.
The steam cylinders receive steam at each stroke of their pistons, and 1
exhaust alternately into another or auxiliary cylinder, which exhaust
steam serves to balance the pistons of the steam cylinders as they begin
to exhaust into the auxiliary cylinder, thereby preventing back pressure
and producing comparatively regular strokes, whilst at the same time
the whole of the exhaust steam is utilized.
1
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 26th November 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middle- !
sex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of May, in the year
of our Lord One thousand eight hundred and seventy-five, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Henry Johnson, Her special license,
that I, the said John Henry Johnson, my executors, administrators, and
assigns, or such others as I, the said John Henry Johnson, my executors,
administrators, or 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

page_text: STEAM ENGINES," a communication to me from abroad by Farrelly
Alden and Abram Alexander, both of Pittsburg, in the State of Penn-
sylvania, United States of America, upon the condition (amongst others)
that I, the said John Henry Johnson, my executors or administrators,
by an instrument in writing under my hand and seal, 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 I, the said John Henry Johnson, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the accom-
panying Drawings and to the letters and figures marked thereon, that is
to say :-
The said Invention relates to compound steam engines employed for
stationary, locomotive, portable, and marine purposes, and has for its
object equalizing the steam pressure on both sides of a piston when its
cylinder is exhausting, and thus balancing the piston, so that on its
return stroke the resistance to its motion, due to the back pressure of
the exhaust steam, will be obviated, whilst at the same time the exhaust
steam is utilized for aiding in the return stroke of such piston.
The Invention consists essentially in the employment of two steam
cylinders in combination with an auxiliary cylinder (or with two of such
cylinders), the steam cylinders being arranged either one at each end
of the auxiliary cylinder in the same axial line therewith, so that the
three pistons are carried upon one and the same piston rod, or one steam
cylinder at each side of the auxiliary cylinder, in which latter case three
piston rods are employed, either connected with one crank common to
the whole or with three cranks, as desired; or the relative positions of
the cylinders may be otherwise arranged, providing that the required
object be attained.
The two steam cylinders alternately are supplied with live steam on
one sido of their respective pistons, and they alternately exhaust to the
opposite side of their respective pistons, and simultaneously to one side
or the other of the piston of the auxiliary cylinder. By means of this

page_text: Invention a uniform motion is obtained, and the whole of the advan-
tages of a low pressure engine are secured without the expense of a
condenser. If found desirable however a condenser may be employed
in combination with the arrangement of cylinders herein-before
mentioned.
And in order that the said Invention may be fully understood I shall
now proceed more particularly to describe the same, and for that purposo
shall refer to the soveral Figures on the annexed Sheet of Drawings, the
same letters of reference indicating corresponding parts in all the
Figures.
Figure 1 of the accompanying Drawings ropresents a longitudinal
section of a steam engine constructed with two steam cylinders and an
auxiliary cylinder, herein-after termed the vacuum or exhaust cylinder,
all arranged in the same axial line according to this Invention; Figure 2
represents a similar view to Figure 1 of a portion of a steam engine,
illustrating a modification in the arrangement of the valves.
Figures 3, 4, 5, and 6, illustrate one mode of carrying out the Inven-
tion when the three cylinders are arranged side by side, Figure 3 being
a transverse section taken along the line 1-2 (Figure 4); Figure 4, a
sectional plan; and Figures 5 and 6 longitudinal sections taken through
the valve boxes along the lines 3-4, and 5-6, respectively (Figure 3).
Referring to Figure 1 of the accompanying Drawings 6 is a large
vacuum or exhaust cylinder, and a, c, are two steam cylinders, all
arranged in the same axial line and provided with pistons b', a', and c',
respectively, having a rod or stem d common to the whole; fand g are
valve boxes, in which are fitted the valves for the supply of live steam
and for the distribution of the exhaust steam. The piston rod d
operates the wheel by means of a connecting rod ¹ and crank, and
the eccentric is connected with and operates the pivoted arm k by
means of the yoke 7 and rod 1. Attached to one end of the arm k is a
rod m, which operates the valves in the boxes fand 7; and to the other
end is connected a rod a, which operates the escape valves n³, n³, n³,
and n. In the valve box fis a slido valve », which operates across the
steam port. In this valve is a steam port 1 and an exhaust port 2. The
port 1 opens directly into the passage 3, and the port 2 opens into the
passage 4 at one end, and at the other end into the passages 3 and 5,
which latter leads to the exhaust cylinder b. In the valve box there

page_text: is a similar slide valve ³ having a series of similar ports and passages,
the steam supply port being marked 6, the exhaust port 7, the passage
from the port 6 to the cylinder c, 8, the passage from the port 7 to the
cylinder c, 9, and the passage from the port 7 to the cylinder 6, 10. The
cylinder a is provided with an escape port 11, the cylinder 6 with two
escape ports 12 and 13, and the cylinder o with an escape port 14.
The engine operates in the following manner :-Commencing with the
cylinder a and assuming the valve r to be in the position shewn in the
Drawing, steam is admitted through the port 1 and passes through the
passage 3 into the cylinder a, where operating between the cylinder
head a' and the piston a³ it forces the piston a¹ back to the opposite
cylinder head a³. At this point the valve operating by means of the
arm k and rod m closes the port 1 while it brings the port 2 across and
in connection with the passages 3, 4, and 5. A portion of the exhaust
steam from the cylinder a then rushes through the port 2 into the
passage 4, and thence into the cylinder a behind the piston a'. This
brings the pressure of the exhaust steam on both sides of the piston and
balances it, so that on its reverse movement it will encounter no
resistance from an unequal pressure on its front side. The remainder of
the exhaust steam passes through the port 2 into the passage 5, and
thence into the cylinder 6 at the rear side of the piston 6¹. At this
instant the reverse stroke of the piston takes place, being caused by the
operation of the piston c³ in the cylinder c. The operation in this
cylinder is the same as that just described. While the piston stem is
moving in a direction the reverse of that just described the exhaust
steam from the cylinder a entering the cylinder 6 in the manner just
described operates against the piston 6', so as to force it onward to the
other end of the cylinder b. When the exhaust steam enters the
cylinder 6 the pressure is very much greater than the pressure of the
atmosphere, but as the piston advances the pressure is gradually reduced
by the dilation of the steam until the piston reaches the farthest limit
of its stroke, at which point, the size of the cylinder being regulated in
reference to the amount of exhaust steam admitted therein, the
has been reduced until it about equals the pressure of the external atmos-
3 phere. Taking now the cylinder c, which is situated at the opposite
end of the cylinder b, the steam is admitted through the port 6 and the
passage 8 into the cylinder c and operates against the piston c', forcing
pressure

page_text: it onward to the cylinder head c³ at the opposite end of the cylinder.
Then by the movement of the valve r¹ the steam supply is cut off and
the port 7 is brought in connection with the passages 8, 9, and 10, that
being the position shewn in the Drawing. A portion of the exhaust
steam from the cylinder c then passes through the port 7 and the
passage 9 to the rear side of the piston c¹ and balances it in the manner
herein-before described in reference to the piston a³, the remainder of
the exhaust steam from the cylinder c passing through the port 7 and
passage 10 enters the cylinders b, where it operates against the piston 6¹
to aid in the reverse movement of the piston in the manner herein-before ]
described. While the piston stem d, which carries all the pistons, is
being moved forward in either of the cylinders a or c the discharge port
in connection with such cylinder is opened to permit the cscape of the
exhaust steam which had been admitted to the rear side of the piston,
while the discharge port of the opposite cylinder is closed to prevent the 1
escape of the exhaust steam as it enters at the back of the piston. Also
the discharge ports on the opposite sides of the piston b¹ in the cylinder b
are alternately opened and closed for the purpose of permitting or
preventing the escape of the exhaust steam from the cylinder b.
It will thus be seen that a portion of the exhaust steam from the 2
cylinders is utilized for the purpose of balancing the pistons in the end
cylinders a and c, while the remainder of the exhaust steam is admitted
to the cylinder 6 and utilized therein for the purpose of aiding in the
reverse stroke of the piston. This gain is constant, because when the
live steam is operating against the piston in one of the cylinders a or c 2
the exhaust steam from the other cylinder is operating in the same
direction against the piston 6', while at the same time there is no
resistance of the exhaust steam in the opposite cylinder a or c.
The size of the cylinder 6 should be regulated by the amount of the
exhaust steam admitted from the cylinder a or c, so that when the 8
piston 6 has reached the end of its stroke the steam which is admitted
therein shall have been dilated or expanded until its pressure has been
reduced to about that of the atmosphere. If the size of the cylinder 6
is less than this, and does not afford sufficient space for the expansion
of the steam to this extent there is a loss of power equal to the 3
difference between the pressure in the cylinder b and the pressure of the
atmosphere.

page_text: In the modification shown in Figure 2 the escape valves n', nº, n³, and nº
are dispensed with, the final escape of the steam, after having done its
duty in the manner herein-before described, being regulated by the
valves r,r. The waste steam from the cylinder a, and the end adjacent
to it of the cylinder b, is allowed to escape at the required periods by
a common outlet passage 11, whereas the waste steam from the cylinder c,
and the end adjacent to the latter cylinder of the cylinder b, is dis-
charged through a common outlet passage 14; 15, 16, are the discharge
pipes for the waste steam, 17, 18, being the inlet pipes for the live
steam. The valves r, r, in Figure 2 are respectively shewn in positions
the reverse of those indicated in Figure 1. The operation of the engine
constructed according to this modification is generally similar to that
herein-before described with reference to the latter Figure.
In the modification illustrated in Figures 3, 4, 5, and 6, the cylinders
a, b, and c are arranged side by side, and are each provided with a
separate piston rod or stem d, the whole being attached to a cross head 19
working along guides 20, and to which is attached the connecting rod h³.
The piston stems d, d, d, may however be coupled to separate connecting
rods and cranks if found desirable. The relative positions of the valves
shewn in these Figures are similar to those indicated in Figure 1, and
the operation of the engine will be readily understood from the descrip-
tion herein-before given without further explanation.

page_text: whilst their own pistons are balanced by the free circulation of the
exhaust steam around them, substantially as herein-before described.
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and seal, the Twenty-sixth day of
November, One thousand eight hundred and soventy-five.