IMPROVEMENTS IN MOTORS WORKED BY COMBUSTIBLE GAS OR VAPOR."
Year: 1881

page_text: ·LETTERS PATENT to Dugald Clerk, of Glasgow, in the County of Lanark,
North Britain, Analytical Chemist, for an Invention of "IMPROVEMENTS IN
MOTORS WORKED BY COMBUSTIBLE GAS OR VAPOR."
PROVISIONAL SPECIFICATION left by the said Dugald Clerk at the Office
of the Commissioners of Patents on the 14th March 1881.
DUGALD CLERK, of Glasgow, in the Oounty of Lanark, North Britain, Analytical
Chemist, "IMPROVEMENTS IN MOTORS WORKED BY COMBUSTIBLE GAS OR
VAPOR."
This Invention has for its object to improve and simplify the construction and
increase the efficiency of gas motors, or motors operating with combustible gas or
vapor.
In one modification of the improved motor there are two single-acting cylinders
provided with pistons connected in the ordinary way to cranks on one shaft. In
one cylinder a mixture of gas or vapor and air is ignited, and power developed,
but the other cylinder is employed to effect displacement only, and the two
cylinders are hereinafter distinguished as the power cylinder and the displacement
cylinder. The air and gas or vapor enter at one end of the power cylinder, and the
exhaust takes place by ports so situated as to be passed by the piston when
approaching the end of its stroke in its movement from the entering end. The
capacity of the displacement cylinder is considerably larger than the product of the
area and stroke of the power piston, and when the displacement piston is moving
in one direction, it draws in air and gas or vapor through a check valve, but the
gas or vapor is cut off as soon as the quantity of mixed air and gas or vapor is
about equal to the product of the area and stroke of the power piston, and only air
is drawn in during the remainder of the stroke of the displacement piston. On the
return stroke the displacement piston forces the contents of its cylinder through a
check valve into the power cylinder, the unmixed air last drawn in first entering
the power cylinder. The cranks of the two cylinders are so placed relatively to
each other, that whilst the contents of the displacement cylinder are being forced

page_text: into the power cylinder the exhaust ports of that cylinder are still open, and not
only do the burnt or used gases of the previous stroke pass out, but also the
unmixed air, which enters in advance of the fresh charge. This portion of unmixed
air insures the clearing out of the power cylinder, and prevents any ignited matter
from remaining in the cylinder to prematurely ignite the fresh charge. On the
return stroke of the power piston, and after it has passed and closed the exhaust
ports, it compresses the mixture of air and gas or vapor into a clearance space at
the end of the cylinder, and the compressed charge is ignited at about the com-
mencement of the succeeding stroke. The ignition is effected by means of a slide
worked by an eccentric on the crank shaft, and moving between a port face on the
side of the power' cylinder and a covering plate, the latter being pressed against the
slide by springs. The covering plate is formed with a small open chamber, in
which a small ignited gas jet is kept constantly burning, and this chamber has a
port past which the slide moves. The slide has a main passage or space formed in
it and extending partly along it, and this main passage has a port on each side.
A very small passage having a port on the inner side of the slide communicates
through a grating with the main passage, and into this small passage there finds its
way some of the combustible mixture from the interior of the power cylinder
through a small passage, and an elongated port or groove in the cylinder port face.
When the slide is in one position, the outer port of its main passage is in com-
munication with the port of the chamber in the covering plate, and then the gas
entering through the grating becomes ignited, but the ignition is not communicated
through the grating nor through the inner port of the slide. The immediately
subsequent movement of the slide cuts off the communication of its outer port, and
brings its inner port into communication with a port leading into the cylinder, and
the flame in the main passage of the slide is thereupon communicated to the
combustible mixture in the cylinder, all communication with the exterior being
completely cut off.
The slide besides having the passages and ports that have been mentioned, is
made with a cavity or port which works in connection with ports and passages
through which the combustible gas or vapor passes on its way from the supply
pipe to the valve through which it is drawn into the displacement cylinder, the
slide causing the gas to be cut off at such period of the indrawing stroke as to
render the later portion of air drawn in unmixed with gas or vapor. The gas or
vapor supply passage is also fitted with a valve controlled by a speed governor.
The inlet check valve through which the air and gas or vapor are drawn into the
displacement cylinder is by preference a conical-seated valve, the seat being of
sufficient breadth to have in it a number of holes, through which a suitable pro-
portion of combustible gas or vapor can enter from an annular passage connected
with the supply passage. In order to prevent as much as possible the air entering
the displacement cylinder during the latter part of the indrawing stroke from
mixing with the combustible mixture previously drawn in, there is placed in the
end of the cylinder a plate which causes the entering air to spread from the centre
to the circumference, and thence enter the interior of the cylinder between the
plate and a ring, and in directions directed more or less towards the centre. Or a
number of inlet ports may be formed round the cylinder itself close to the end for
the same purpose.
In other modifications two or more sets. of the single-acting cylinders may be
connected to one crank shaft, or the cylinders may be made double-acting by
duplicating such parts as may be necessary.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Dugald Clerk in the Great Seal Patent Office on the 13th September
1881.
DUGALD CLERK, of Glasgow, in the County of Lanark, North Britain, Analytical
Chemist. "IMPROVEMENTS IN MOTORS WORKED BY COMBUSTIBLE GAS OR
VAPOR."
My said Invention has for its object to improve and simplify the construction
and increase the efficiency of gas motors or motors operating with combustible gas
or vapor.
In one modification of my improved motor there are two single-acting cylinders
provided with pistons connected in the ordinary way to cranks on one shaft. In
one cylinder a mixture of gas or vapor and air is ignited and power developed, but
the other cylinder is employed to effect displacement only, and the two cylinders
are hereinafter distinguished as the power and the displacement cylinder. The
air and gas or vapor enter at one end of the power cylinder, and the exhaust
takes place by ports so situated as to be passed by the piston when approaching
the end of its stroke in its movement from the entering end. The capacity of the
displacement cylinder is considerably larger than the product of the area and
stroke of the power piston, and when the displacement piston is moving in one
direction it draws in air and gas or vapor through a check valve, but the gas or
vapor is cut off as soon as the quantity of mixed air and gas or vapor is about
equal to the product of the area and stroke of the power piston, and only air is
drawn in during the remainder of the stroke of the displacement piston. On the
return stroke the displacement piston forces the contents of its cylinder through a
check valve into the power cylinder, the unmixed air last drawn in first entering the
power cylinder. The cranks of the two cylinders are so placed relatively to each
other that whilst the contents of the displacement cylinder are being forced into the
power cylinder the exhaust ports of that cylinder are still open, and not only do
the burnt or used gases of the previous stroke pass out but also the unmixed air,
which enters in advance of the fresh charge. This portion of unmixed air insures
the clearing out of the power cylinder, and prevents any ignited matter from
remaining in the cylinder to prematurely ignite the fresh charge. On the return
stroke of the power piston, and after it has passed and closed the exhaust ports, it
compresses the mixture of air and gas or vapor into a clearance space at the end of
the cylinder, and the compressed charge is ignited at about the commencement of
the succeeding stroke. The ignition is effected by means of a slide worked by an
eccentric on the crank shaft, the details of and connected with this slide being
hereinafter particularly described. Besides having passages and ports which have
to do with the power cylinder, the slide is made with a cavity or port operating in
connection with ports and passages through which the combustible gas or vapor
passes on its way from the supply pipe to the valve, through which it is drawn
into the displacement cylinder, the slide causing the gas or vapor to be cut off at
such period of the indrawing stroke so as to render the later portion of air drawn
in unmixed with gas or vapor. The gas or vapor supply passage is also fitted with
a valve controlled by a speed governor.
In other modifications of my improved motor two or more sets of the single-
acting cylinders may be connected to one crank shaft, or the cylinders may be
made double-acting by duplicating such parts as may be necessary.
And in order that my said Invention, and the manner of performing the same,
may be properly understood, I hereunto append three Sheets of explanatory
Drawings, to be hereinafter referred to, and representing a modification of my

page_text: improved motor as arranged with a single-acting power cylinder and a single-
acting displacement cylinder for operating with ordinary illuminating gas.
Figure 1 on Sheet of the Drawings is a plan, and Figures 2 and 3 are end and
side elevations; Figure 4 on Sheet 2 is an enlarged horizontal, section; and
Figures 5 and 6 on Sheet 3 are an enlarged end elevation and an enlarged longi- 5
tudinal vertical section; whilst Figure 7 is an enlarged horizontal section of the
valve slide. In these Drawings the same reference numerals are used to mark the
same or like parts wherever they are repeated.
"
In the modification shown in the Drawings a single-acting power cylinder 11 is
fixed horizontally in a jacket casing 12 formed at one end of a bed frame 13, which 1
is at its other end provided with bearings for the crank shaft 14. The piston 15
of the power cylinder is in the form of a hollow plunger or ram, but is fitted with
a number of metallic packing rings, and no stuffing box is required at the front
end of the cylinder. The connecting rod 16 of the power piston is jointed on a
double cheeked crank on the shaft 14 between the bearings, and outside of the
bearings there are at one side of the machine an eccentric 17 for working the valve
slide, and a pulley 18 for the belt, which transmits the power from the machine,
whilst at the other side the shaft 14 has on it a flywheel 19 and a pulley 20, a
strap from which last drives the speed governor. The flywheel 19 has on it a crank
pin 21, on which is jointed the connecting rod 22 for working the piston 23 of the
displacement cylinder 24. The displacement cylinder 24 is placed horizontally at
one side of the power-cylinder jacket 12, being formed in a casting 25, which is
bolted to the jacket 12, and which is formed with and carries various parts herein-
after described. At the inner end of the power cylinder 11 there is a conical
clearance space 26 formed in the casting 25, as is also a jacket space 27, which
communicates with the space in the jacket 12 surrounding the power cylinder 11.
Water entering by a pipe 28, and passing off by a pipe 29, is supplied to the
jacket spaces 12, 27, to prevent the power cylinder 12 and clearance space 26 from
becoming overheated.
The air and gas enter to the power cylinder 11 by an inlet 30 at the outer end
of the conical clearance space 26, and the exhaust takes place through ports 31
communicating with a passage 32 formed round the cylinder, and leading to the
exhaust pipe 33, these exhaust ports 31 being uncovered by the piston 15 as it
approaches the outer end of its stroke. A pipe 34 fitted with a stopcock 35 forms
a communication between the exhaust pipe 33 and a part of the cylinder 11 nearer
the inner end, and is provided to facilitate the starting of the motor, the opening
of the stopcock 35 having the effect of reducing the compression and the force
developed at each stroke.
Below the inlet 30 to the power cylinder there is a valve box 36, having in it
two check valves 37, 38, whilst the space between them communicates by a pipe 39
with the displacement cylinder 24, and the action of the displacement piston 23 is
to draw in air and gas through the lower valve 38, and subsequently force them
through the upper valve 37 into the power cylinder 11. With the view of
diminishing or preventing the production of noise by the drawing in of the air a
chamber or box 40 is fixed below the lower check valve 38, and the air enters this
chamber 40 through a number of holes 41 formed round the bottom of it, and
having above them a light rubber disc 42. The opening of the lower check valve 38
admits gas as well as air (unless the gas happens to be shut off), there being in the
conical seat of the valve a number of small holes, which communicate with an
annular passage 43, to which the gas has access by a vertical passage 44 indicated
by dotted lines in Figure 5.
The valve slide 45, which is of a rectangular form in cross section, is fitted to
work horizontally across the back end of the power cylinder, or rather, of the back
casting 25, a recess being formed for it in that casting, and having a vertical port-
face piece fixed at its innermost part. The valve slide 45 is kept in position by an
adjustable covering plate 46, which is pressed against the slide by a bar 47 acted
on by adjustable helical springs 48 on spindles or studs passing through the

page_text: covering plate 46, and fixed in the casting 25. The valve slide 45 is directly
acted on by a bellcrank lever 49, itself moved by a bar 50 working in guides, and
having jointed to it the connecting rod 51 of the eccentric 17. The covering
plate 46 is formed with a small open-topped chamber 52, in which a jet from a
small gas pipe 53 (by preference arranged like a Bunsen burner) is kept constantly
burning. Air enters this chamber 52 by holes in its bottom, and it has at its
inner side a port, past which the valve slide 45 moves. The slide 45 has a main
passage or space 54 formed in it, and extending partly along it; and this main
passage 54 has a port on each side. A very small passage shown in section in
Figures 6 and 7, and indicated by dotted lines in Figure 4, which passage bas an
elongated port 8 on the inner side of the slide 45, communicates through a
grating 55 with the main passage 54 near its port on the outer side of the slide,
and through this small passage there finds its way some of the combustible mixture
through a small bore indicated by horizontal dotted lines just above the port 57 in
Figure 6. As it is desirable to regulate the quantity passing to the grating 55 a
slightly enlarged bore is formed from the further end of the slide 45, into which
bore there is screwed a spindle 9 made with a point, which closes the small gas
passage more or less, accordingly as the spindle 9 is adjusted, a jam nut serving
to fix the spindle when adjusted. When the slide 45 is in one position, which is
that it is shown in, in Figure 4 the outer port of its main passage 54 is-in com-
munication with the port of the chamber 52 in the covering plate 46, and then the
gas which has entered the passage 54 through the grating 55 becomes ignited.
At this time the inner port of the main passage 54 of the slide communicates with
a passage 56 leading to the outside, which insures the filling of the passage 54
with flame, and affords visible indication of this part of the ignition being properly
effected. The immediately subsequent movement of the slide 45 cuts off the
communication of the outer port of its passage 54, and brings its inner port into
communication with a port 57 leading into the end of the clearance space 26 of
the power cylinder 11, and the flame in the main passage 54 of the slide 45
is thereupon communicated to the combustible mixture in the space 26, all
communication with the exterior being completely cut off.
The valve slide 45, besides effecting the ignition of the combustible gaseous
mixture in the power cylinder, also controls the admission of the combustible gas into
the displacement cylinder. The vertical passage 44, which as hereinbefore mentioned
leads the gas to the lower check valve 38 through which the air is drawn in, has
at its upper end a port in the port face upon which the valve slide 45 works, and a
cavity 58 in the slide puts that port at the proper times in communication with
the port of a passage. 59, which leads the gas from the supply pipe 60, the latter
being provided with a stop valve 61 for completely shutting off the gas when the
motor is not working. The valve slide 45 allows the gas to enter mixed with air
during the early part of the indrawing stroke of the displacement piston 23, but
cuts it off at a suitable part of the stroke, so that only air enters during the
remainder of the stroke; and in order to prevent as much as possible the air last
drawn in from mixing with the combustible mixture previously drawn in, there is
placed in the end of the displacement cylinder 24 a plate 62, which causes the
entering air to spread from the centre to the circumference, and thence enter the
interior of the cylinder between the plate 62 and a ring 63, and in directions
directed more or less towards the centre. Or a number of inlet ports may be
formed round the cylinder itself close to the end for the same purpose.
Any suitable kind of speed governor may be used, the one shown in the Drawings
having a horizontal spindle 64 carried in a long bearing in a bracket 65. On one
overhanging end of the spindle 64 there is a pulley 66 to receive the driving belt
from the pulley 20 on the crank shaft 14; and within this pulley 66 there are
jointed the arms of a pair of centrifugal balls 67. A helical spring placed inside of
the spindle 64, which is hollow, is applied to resist the centrifugal tendency of the
balls 67, but this tendency in proportion as it increases from increased speed moves
a central spindle 68 outwards at the other end of the bearing. The spindle 68 bas.

page_text: on it a pair of collars by which it acts on a lever 69. centered on a small
bracket, and when the proper speed is exceeded this lever 69 is moved so as to
bring its bottom end over a horizontal part of a curved or bell-crank lever 70. A
rod 71 passing through a hole in the lever 70 and resting thereon by a nut screwed
on its end passes down through a stuffing box to a valve 72 (indicated by dotted
lines in Figures 5 and 6) in the gas passage 44, and this valve 72 has a spring
applied to it which tends to keep it shut; it is however periodically opened by the
action of the lever 70, one arm of which extends down beside the covering plate 46
and is acted on by a small block 73 fitted to slide in a slot in the plate 46. A
spiral spring 74 makes the lever 70 tend to open the valve 72, and at the same
time to press the block 73 inwards, but the valve slide 45 keeps the parts in the
positions for having the valve 72 shut, except when a curved recess formed for the
purpose in the slide comes opposite the block 73. At such times the block 73 can
move inwards, and then the spring 74 makes the lever 70 open the valve 72 and
allow the gas to pass; but if the speed is at any time excessive the governor moves
the lever 69 over the lever 70, which for the time prevents the lever 70 from
opening the valve 72, and the supply of gas is in consequence shut off for one or
more strokes.
Lubricators 75 are fitted for lubricating the piston or ram 15 and the valve
slide 45. In each case the lubricator 75 is fitted with a central valve spindle 76,
the valve on which closes a communication from the bottom of the reservoir into
an annular passage from which there is an open spout 77, and the lubricant drops
from this spout down a passage 78 leading to the rubbing surfaces. The valve
spindle 76 extends down into a chamber below the lubricator, in which chamber
there is applied to it a spring tending to close the valve. The chamber has an
opening through into the interior in which the piston or ram 15 works, and in this
opening there is fitted a small movable block, which when the valve is shut
projects down into a recess formed in the surface of the piston or ram 15 (but
which recess is too small to be shown in the Drawing). As the piston or ram
moves the unrecessed part comes under and raises the movable block and through
it the valve spindle 76, and allows a little lubricant to pass out by the spout 77.
The upper end of the spindle 76 is squared and enters a square hole in the cover 79,
by turning which the spindle can be screwed more or less into the nut which is
at its bottom end and which compresses the spring. By these means the extent
of opening of the valve can be adjusted and the rate of flow of the lubricant
thereby regulated; and it can be seen at any time how the lubricator is working
by watching the lubricant dropping from the spout 77 into the passage 78. A
clamping ring 80 screwed on the rim of the lubricator cup serves for fixing the
cover 79 when adjusted.
The displacement cylinder 24 is represented as having a capacity about equal
to double the product of the area and stroke of the power piston, and the crank 21
for working the displacement piston 23 is placed a little more than a quarter of
a circle in advance of the crank of the power piston 15; these relative proportions
and arrangement may however be varied in different cases.
Having thus particularly described ny said Invention and the manner of
performing the same, I have to state that I do not restrict myself to the precise
details herein described or delineated, but that what I believe to be novel and
original, and claim as the Invention secured to me by and in terms of the herein-
before in part recited Letters Patent is,―
1. The combination of the power cylinder. with the displacement cylinder, the
said cylinders and their accessories being constructed, arranged, and operating
substantially in the manner herein before described.
2. The expelling of the used gases by air which enters behind them from the
displacement cylinder in advance of the next succeeding charge of combustible
gaseous mixture, and a portion of which air is also itself expelled, the operation
being effected by apparatus arranged or combined substantially as hereinbefore
described.

page_text: 3. The arrangement of the displacement cylinder and valves working in
connection therewith, so that a mixture of air and combustible gas or vapor enters
during the earlier part of the indrawing stroke and air alone during the remainder
of the stroke, substantially as and for the purposes hereinbofore described.
4. The combination of the parts of the valve slide (45) covering plate (46)
grating (55) and the port (57) for effecting ignition in the power cylinder,
substantially as hereinbefore described.
5. The application of the grating (55) at which is ignited the combustible
mixture used for conveying flame into the power cylinder, and by means of which
in combination with the passage (54) the flame is rendered certain and steady,
substantially as herein before described.
6. The device for drawing in together and mixing the combustible gas or vapor
and air, and consisting of the valve (38) and the seating through perforations in
which seating the combustible gas or vapor enters whilst the air enters by the
central opening, substantially as herein before described.
7. The herein before described combination of parts through which the movement
of the central governor spindle (68) affects the action of the valve (72).
In witness whereof, I, the said Dugald Clerk, have hereunto set my hand
and seal, this Twelfth day of September, in the year of our Lord One
thousand eight hundred and eighty-one.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
DUGALD CLERK: (L.S.)