IMPROVEMENTS IN STEAM ENGINES
Year: 1873

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn
Fields, in the County of Middlesex, Gentleman, for the Invention
of "IMPROVEMENTS IN STEAM ENGINES."-A communication from
abroad by George Granville Lobdell, of the City of Wilmington,
County of New Castle, State of Delaware, United States of
Amering
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 20th August 1873.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the
5 County of Middlesex, Gentleman, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN STEAM ENGINES," a communication
to me from abroad by George Granville Lobdell, of the City of
Wilmington, County of New Castle, State of Delaware, United States of
Amanian to ho so follows.

page_text: importance in connection with condensing engines, as they tend to the
production of a more perfect vacuum than has hitherto been attained in
engines of that class.
The steam cylinder when of the oscillating kind has tubular trunnions
common to other vibrating or oscillating cylinders, and two exhaust
steam chests with two live steam chests.
This cylinder is encased throughout its whole length by a jacket, the
space between which and the said cylinder is separated by a partition
into two passages, one for the conveyance of live steam from onc
trunnion to the steam chests, and the other for directing the exhaust
steam to the other trunnion.
It will be evident that this plan of devoting the space within the
jacket surrounding a cylinder partly to a steam passage, and partly to
a passage for exhaust steam is applicable to fixed cylinders, and that the
plan serves to maintain the interior of the cylinders at the desired high
temperature.
Through each chest passes a spindle, the outer end of which is-adapted
to a socket fitted to a bracket attached to the cover of the chest, a spiral
spring contained in the socket. being caused to bear..against the end of
the spindle by a set screw, and the opposite end of the spindle fitting
into a socket in the rear cover of the chest which has a set screw for
causing a spring to bear against this end of the spindle.
The valve seat consists of a tapering circular sleeve fitted tightly into
annular ribs within, and forming part of the chest, the seat having a
number of oblong slots in two sets separated from each other by an
annular rib, there being in the present instance six slots in each set.
To the seat is fitted a tapering valve having a central hub for attach-
ment to the spindle, the valve having slots corresponding with those of
the sleeve..
It is preferred to place the valve and its seat eccentrically in the chest,
so that the passage around the seat for the steam will be commensurate
with its volume:
:
It is essential to the proper working of these valves that they should
have considerable taper, and that provision should be made for accurate
cilinatmont This is soonved by not sonore noting on the annouits and

page_text: the valve spindle through elastic mediums, which will prevent the valve
from becoming either too tight or too loose in its seat, and will insure
freedom of movement. In condensing engines the imperfection of the
vacuum which detracts so seriously from the power of the engine is
attributable mainly to the leakage of the valves. This is especially the
case when double beat valves are used as they are most difficult to keep
tight. The same defect is also observable in slide valves, but a tapering
circular valve of the character described can be maintained so tightly in
its seat under all circumstances that it becomes especially valuable in
condensing engines.
An important feature of this part of the Invention is the making of
the valve scat separate from the cylinder, for when it is worn it can be
readily removed to make way for a new one without any necessity for
reboring the chest.
I shall now describe the manner of operating the valves which forms
the second part of this Invention. The spindle of the steam valve in
cach chest is furnished with an arm which is connected by a rod to
another arm, the two latter arms being hung by pins to a bracket
secured to one of the trunnions, a spring tending to force each arm
against a stop on the said bracket. To guides on the framework of the
engine is adapted a horizontal slide which is under the control of the
governor of the engine, the governor rod being connected to the long
arm of a bell-crank lever hung to a projection on the guide, and the
short arm of the lever having a pin entering the slide. To this slide are
hung two steel pointed dogs, each dog being acted on by a spring which
tends to maintain it in contact with a shoulder or stop on the slide.
Supposing the upper part of the cylinder to be moving from left to right,
the upper arm will be retained by the upper dog for a length of time
depending upon the distance of the end of the dog from the outer end
of the arm, and as this distance depends upon the governor, the valve for
admitting steam to the upper portion of the cylinder will remain open
for a length of time commensurate with the speed and requirements of
the engine.
The moment the arm is released from the dog it will be elevated by
the spring, and the valve will be closed. When the cylinder moves in a
contrary direction the same operation of the lower arm and lower valve
will take place, while the rounded end of the upper arm acting on the
bevelled end of the upper dog will depress and finally pass the latter pre-

page_text: paratory to a repetition of the above described movements. It will be
seen without further description that as the cylinder vibrates the steam
valves are opened alternately, the time of opening being always the same,
but the time of closing in accordance with the speed and requirements
of the engine.
The arms of the exhaust valves within the exhaust steam chests are
connected by rods to a fixed pin on the frame of the engine, so that the
opening and closing of these valves will be uniform and in accordance
with the demand for a free and uninterrupted disposal of the exhaust
steam.
Substantially the same valve gear may be applied to an engine with
a fixed cylinder, an eccentric being fitted on the crank shaft of the
engine, and the rod of the eccentric being connected to a bar which may
be guided or suspended by arms so as to receive a longitudinal recipro-
cating movement from the said eccentric. This bar has projections for
bearing against arms connected to levers hung to fixed pins, and con-
trolled by the governor rod, each arm having a spring dog similar to
those on the slide before mentioned.
A spring arm is secured to each spindle of the steam valve, and these
arms are operated by dogs precisely as the arms previously described are
operated, the points in the stroke of the engine where the arms are
released so as to be operated by the springs depending upon the action of
the governor.
The exhaust valves have an uniform vibrating motion imparted to
them from a reninmonating has theuch
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Scal Patent
Office on the 13th February 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, send greeting.
•
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Tatton Datamat

page_text: .
•
of our Lord One thousand eight hundred and seventy-three, in the 37th
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, adminis-
trators, 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
STEAM ENGINES," a communication to me from abroad by George Gran-
ville Lobdell, of the City of Wilmington, County of New Castle, State of
Delaware, United States of America, upon the condition (amongst
others) that I, the said John Henry Johnson, my executors or adminis-
trators, 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 licreby
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 tho letters and figures marked thereon, that
is to say:-
The first part of this Invention relates to the construction of valves
applicable to steam engines generally, but especially to condensing
engines in which they tend to produce a more perfect vacuum than as
hitherto been attained.
And in order that the said Invention may be fully understood, I shall
now proceed more particularly to describe the same, and for that
purpose shall refer to the several Figures on the annexed Sheet of.
Drawings, the same letters of reference indicating corresponding parts
in all the Figures.
5 Figure 1 of the Drawings represents a vertical section of a vibratory
cylinder fitted with the improved valves. Figure 2, a transverse
sectional plan of same on the line 1-2, in Figure 1.

page_text: Figure 3, a longitudinal section of one of the valves and its seat
drawn to an enlarged scale, and Figure 4 a transverse section of
same.
A represents a steam cylinder having tubular trunnions a, a, similar
to those of other vibrating cylinders, also two exhaust steam valve
chests b, b, and two steam valve chests d, d.
The cylinder A is encased throughout its whole length by a jacket,
the space between which and the said cylinder is separated by a partition
into two passages (see Figure 2), one marked d for the conveyance of
live steam from trunnion a to the steam valve chests d, d, and the other
marked for directing the exhaust steam from the valve chests b, b, to
the other trunnion a¹.
It will be evident that this plan of using the space within the jacket
surrounding a cylinder partly as a steam passage, and partly as a
passage for exhaust steam is also applicable to fixed cylinders, and
serves to maintain the interior of the cylinders at the desired high tem-
perature.
Through each valve chest passes a spindle e, the outer end of which
is adapted to a socket fitted to a bracket D attached to the cover E of
the chest, a spiral spring contained in the socket being caused to bear
against the end of the spindle by a set screw h, and the opposite end of
the spindle fitting into a socket in the rear cover E¹ of the chest, which
has a set screw ' for causing a spring to bear against this end of the
spindle.
The valve seat F. (see Figures 3 and 4) consists of a circular tapering
sleeve fitted tightly into annular ribs i (sec Figure 2) within and
forming part of the chest, the seat having a number of oblong slots j,j,
in two sets separated from each other by an annular rib %, there being in
the present instance six slots in each set, as shewn in Figure 4. To the
scat is fitted the tapering valve G having a central hub m for attachment
to the spindle e, the valve having slots corresponding with those of the
sleeve. This description applies to all the valves shewn on the Drawing.
The manner in which these valves by their vibratory movement admit
the steam from one trunnion to the cylinder and exhaust it from the
latter through the other trunnion to the condenser will be readily
understood.

page_text: It is preferred to place the valve and its seat eccentrically in the chest,
as shewn in Figure 5, so that the passage around the seat for the steam
will be commensurate with its volume.
It is essential to the proper working of these valves that they should
have considerable taper, as shewn in Figure 3, and that provision should
be made for accurate adjustment. This is secured by the set screws h
and acting on the opposite ends of the valve spindle through elastic
mediums, which will prevent the valve from becoming either too tight
or too loose in its seat, and will insure freedom of movement as I have
found by practical tests. In condensing engines the imperfection of the
vacuum which detracts so seriously from the power of the engine is
attributable mainly to the leakage of the valves. This is especially the
case when double beat valves are used, as they are most difficult to keep
tight. The same defect is also observable in slide valves, but it is found
by practical tests extending over many months that a tapering circular
valve of the character described can be maintained as tightly in its seat
under all circumstances that it becomes especially valuable in condensing
engines, in proof of which it is found that in an engine now in operation
and fitted with this description of valves, a vacuum of twenty-nine inches
has been constantly maintained, this being a much more perfect vacuum
than can be attained in an ordinary condensing engine.
An important feature of this part of the Invention is the making of
the valve seat separate from the cylinder, for when it is worn it can be
readily removed and a new one substituted without any necessity for
reboring the chest.
The second part of the Invention relates to the manner of operating
the valves, and is illustrated by Figure 6 on the Drawings in connection
with a vibrating engine.
The spindle e of the steam valve in each chest d is furnished with an
arm H which is connected by a rod I to an arm J, the two arms J, J,
being hung by pins n, n, to a bracket K secured to one of the trunnions a,
a spring p tending to force each arm J against a stop q on the, said
bracket. To guides L, L, on the framework of the engine is adapted a
horizontal slide M which is under the control of the governor of the
engine, the governor rod being connected to the long arm of a bell-
crank lover hung to a projection on the guide L, and the short arm of
the lever having a pin entering the slide M. To this slide are hung two

page_text: steel pointed dogs v, v, each dog being acted on by a spring which tends
to maintain it in contact with a shoulder or stop on the slide. If we
suppose the cylinder to be moving in the direction of the arrow Figure 6,
the upper arm J will be retained by the upper dog v for a length of time
depending upon the distance of the end of the dog from the outer end of
the arm, and as this distance depends upon the governor the valve for
admitting steam to the upper portion of the cylinder will remain open
for a length of time commensurate with the speed and requirements of
the engine.
The moment the arm J is released from the upper dog v, it will be
elevated by the spring p, and the valve will be closed. When the
cylinder moves in a direction contrary to that pointed out by the arrow,
the same operation of the lower arm J and lower valve will take place
while the rounded end of the upper arm acting on the bevelled end of
the upper dog will depress and finally pass the latter preparatory to a
repetition of the above described movements. It will be seen without
further description that as the cylinder vibrates, the steam valves are
opened alternately, the time of opening being always the same, but the
time of closing in accordance with the speed and requirements of the
engine.
The arms H¹ of the exhaust valves within the chests b, b, are con-
nected by rods I' to a fixed pin w on the frame of the engine, so that the
opening and closing of these valves will be uniform and in accordance
with the demand for a free and uninterrupted disposal of the exhaust
steam.
Substantially the same valve gear may be applied to an engine with
a fixed cylinder in the manner illustrated in Figure 7, where m represents
an eccentric on the crank shaft of the engine, the rod of the eccentric
being connected to a bar n which may be guided or suspended by arms
so as to receive a longitudinal reciprocating movement from the eccentric.
The bar n has projections n², n³, for bearing against arms z, z, connected
to levers a¹, x¹, hung to fixed pins y, y, and controlled by the governor
rod y¹, each arm having a spring dog - similar to those on the slide m, in
· Figure 6.
A spring arm J¹ is secured to cach spindle c of the steam valve, and
those arms are operated by the dogs v, v, on the arms a; a, precisely as
the arms J, J, in Figure 6 are operated, the points in the stroke of the

page_text: engine where the arms J, J, are released so as to be operated by the
springs p³, p¹, depending upon the action of the governor, the exhaust
valves of which, f¹, f¹, are the spindles, have an uniform vibrating motion
imparted to them from the reciprocating bar n through a system of levers
1, 2, and 3, as shewn on the Drawings..
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion that what I consider to
be novel and original and therefore claim as the Invention secured to me
by the herein-before in part recited Letters Patent is,―
First. The combination with a condensing steam engine of vibratory
circular and slotted valves of a tapering form working in slotted sleeves
of a corresponding taper, substantially as and for the purposes herein-
before set forth.
Second. The combination of the tapering slotted valve G with the.
detachable slotted scat or sleeve F, fitted to the steam chest in the
manner described for the purpose specified.
Third. A steam engine cylinder provided with a jacket, the space
between which and the said cylinder is separated by a partition into two
passages, one for the live steam, and the other for the exhaust steam,
substantially as set forth.
Fourth. The combination of the circular tapering steam valves with
arms operated partly by or through the medium of spring dogs con-
trolled by a governor, and partly by springs, as shewn in Figures 6 and 7,
substantially as and for the purpose herein-before described.
In witness whereof, I, the said John Henry Johnson, have to
this my Specification set my hand and seal, the Thirteenth
day of February One thousand cight hundred and seventy-
four.