IMPROVEMENTS IN MOTIVE- POWER ENGINES
Year: 1878

page_text: LETTERS PATENT to Andrew Barclay, of Kilmarnock, in the County of Ayr,
North Britain, Engineer, for the Invention of "IMPROVEMENTS IN MOTIVE-
POWER ENGINES."
Sealed the 29th October 1878, and dated the 1st May 1878.
PROVISIONAL SPECIFICATION left by the said Andrew Barclay at the Office"
of the Commissioners of Patents on the 1st May 1878.
ANDREW BARCLAY, of Kilmarnock, in the County of Ayr, North Britain, Engineer.
"IMPROVEMENTS IN MOTIVE-POWER ENGINES."
The improvements constituting this Invention relate to that class of motive-power
engines which are driven by steam, gas, air, or equivalent motive agent.
The first part of the improvements relate to the slide valves of such engines, and
this part consists in the adaptation of a packing ring to the back of such valves for
the purpose of displacing the pressure of the motive agent from the back of such
valves.
The packing ring has two working surfaces at right angles to each other, viz. :-
the vertical or cylindrical surface which fits and works in a cylindrical receptacle,
either on the back of the valve or in a similar receptacle on the inner side of the
steam chest cover or equivalent plate, and a horizontal surface which bears either
against the under side of the steam chest cover or the back of the valve or
equivalent surface.
The packing ring herein-before mentioned is kept in its place when the steam is
off by one or more springs, and any pressure of the motive agent which may accu-
mulate inside the packing ring is allowed to escape through a hole either in the
steam chest cover or in the back of the slide valve.
The second part of the improvements relate to the working of the slide valve
in engines which are not provided with a rotating crank or equivalent shaft.
This part of the improvements consists of a tappet rod driven from the piston
rod of the engine. The tappets on this rod are for the purpose of actuating the

page_text: levers by means of which the slide valve is moved into some of its several
positions, and for freeing the cataracts by which the valve is moved into certain of
its other positions. The outer portion of the valve spindle has formed on it, or is
fitted with a frame with slots and cross pieces, in and upon which the wipers,
by which the valve is driven, act. The valve gearing is also provided with
interlocking quadrants for the purpose of holding the valve gear and its con-
nections in a locked or free condition.
In place of using the ordinary water cataract as applied to Cornish pumping and
other engines, by preference I employ a steam cylinder fitted with a piston in
direct connection with the steam pipe or other conduit for the conveyance of
the motive agent, the pressure of the steam or other motive agent acting in place
of the ordinary weights in operating the cataract.
In place of the foregoing arrangements for operating the valve, what is known as
a weighted tumbling lever in combination with tappets and levers with the cataract
may be used.
The third part of this Invention relates to apparatus for controlling the action of
the motive agent admission valve of engines. This consists of a small cylinder pro-
vided with a pair of valves opening outwards to the atmosphere, and with another
pair of valves, one between each end of the cylinder, and another smaller cylinder
connected thereto. Both cylinders are fitted with a piston and piston rod. The
piston of the cylinder first referred to is connected by levers to the piston rod of
the engine, and by these the piston of the one cylinder is operated. The effect of
BO operating the piston is to form a partial vacuum under the piston of the
smaller cylinder and in opposition to the tension of a spring tending to draw
that piston outwards. The extent of vacuum is regulated by a. variable orifice
by which the admission of air is controlled. The piston rod of the small cylinder
last referred to is connected with the lever which opens and closes the admission or
throttle valve, and a lock is provided for keeping the valve entirely closed when
necessary.
The fourth part of these improvements relate to the expansion and slide valve
gear of motive-power engines, and the object of this part of the improvements is to
enable the engineman to govern the speed of the engine by the expansion gear alone,
and for preventing the wire drawing of the steain or other motive agent. In this
improved gear the expansion valve handle and the main slide valve or reversing
handle are mounted, preferably, on the same centre, and they are preferably provided
with interlocking gear, so that they can be united and work as one when the engines
are not working expansively, or when stopping and starting. Or the handles may
work separately.
Under one modification the levers herein-before referred to are connected to two
separate link motions, and the arrangement is such as to admit of the engineman
varying the expansion as the load on the engine requires.
Under a second modification the link motion of the expansion valve is dispensed
with, and the expansion valve is operated by tappet rods actuated by a handle or
by a governor.
The valve gear last herein-before described may also be used for actuating the
expansion valves of Cornish engines, by using the handle to adjust the position of
a wedge or its equivalent. This is also applicable to winding and other engines
with Cornish or double-beat valves, and for reversing the eccentric.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Andrew Barclay in the Great Seal Patent Office on the 1st November
1878.
ANDREW BARCLAY, of Kilmarnock, in the County of Ayr, North Britain, Engineer.
"IMPROVEMENTS IN MOTIVE-POWER ENGINES."
The improvements constituting my said Invention relate to that class of motive-
power engines which are driven by steam, gas, air, or equivalent motive power.
I will describe the improvements as applied to engines whose motive power is steam,
from which description their application to engines driven by other motive power
'will be readily understood.
The first part of the said improvements relates to the slide valves of such engines,
and this part consists in the adaptation of a packing ring to the back of such valves
for the purpose of displacing the pressure of the motive agent from the back of such
-valves.
In Figure 1 of the accompanying Drawings is illustrated, in longitudinal section,
a slide valve A, with my improvements applied thereto. The said valve has cast
or formed on its back a cylindrical receptacle a, extending to near the steam chest
cover, so as to leave a small clearance between itself and the said cover.
In the receptacle A is contained the packing ring b, having two working surfaces
at right angles to each other, viz., the surface which fits and works in the cylindrical
receptacle a, and the surface which bears against the under side of the steam chest
cover. The said packing ring is kept in steam-tight contact with the steam chest cover
by means of a spring or springs, as at c; a hole e is formed in a steam chest
cover to allow of the escape of any steam which may leak between the ring band
the said cover, and thus such leakage is readily detected.
In Figure 2 is shewn a plan of the packing ring b. It consists of two eccentric
spring rings b', 62, one encircling the other, and whose open parts bs and b₁ are
preferably diametrically opposite, and of a ring 6 pressing upon the rings 61, 62, as
indicated by dotted lines in Figure 2, the said ring being of such breadth at the
part be, that it completely covers the opening b in the outer ring, which opening is
presented towards the steam passing to the cylinder. Where more outward pressure
is required than is obtainable from the springs shewn, other springs may be placed
inside the rings b', 62. The area of the exhaust side of the slide valve and the area
above presented to the atmosphere are so proportioned that the valve is as far as
possible in equilibrium.
Figure 3 is a longitudinal section of a modification of the before-described
improvement, in which the receptacle a is cast or fixed on the steam chest cover.
The top of the said receptacle is open, as shewn, and the packing ring b, similar to
that before described, is pressed into steam-tight contact with the back of the slide
valve by the spring c. The ring can then be removed or adjusted without removing
the steam chest cover.
The second part of the improvements relates to the working of the slide valve
in engines which are not provided with a rotating crank or equivalent shaft.
Figure 4 illustrates in side elevation, partly in section, an engine provided with
these improvements. A tappet rod f is connected to the piston rod F by the arm f¹
so as to partake of its motion, the said rod f sliding in a guide f2 upon the cylinder.
Upon the said tappet rod fare two tappets f³, fs, which actuate arms or levers g³, g*,
the arm lying in the path of the tappet f³, and the arm g lying in the path of the
tappet The arm g³ is keyed or fixed on a shaft G¹, upon which are also keyed
wipers, h, a locking quadrant i, and the arm j, to which the cataract J is connected.
The arm g is similarly keyed or fixed on a shaft G³, on which are also keyed the
wipers ³, h, locking quadrant ¹ and arm j, to which the cataract J' is connected.
The outer portion of the valve spindle has formed on it or is fitted with a frame k,

page_text: with slots and cross pieces k³, k², k, k, upon which the wipers h¹, h², h³, k, act.
The sliding of the valve into position for shutting off the steam from the cylinder is
effectedby the engine itself, and the further movement of the said valve to open the
steam passages to the cylinder is effected by the cataracts, as herein-after described.
The Drawing represents the piston rod at near the termination of its forward
stroke. In this position the cataract J' is prevented from turning the shaft G³ by
reason of the quadrant i¹ bearing against the quadrant i, which quadrant i is
maintained in the position represented by its cataract J. As the piston completes
its forward stroke, the tappet fs bearing against the arm g³ turns the said arm into
a raised position (similar to that represented with regard to the arm g'), and the
shaft G! being turned with it, the wiper 2 by bearing against the cross piece ³
.shifts the slide valve into position in which it cuts off steain to the cylinder. The
cataract J is at the same time raised, and the quadrant i is also turned down clear
of the quadrant i, and the cataract J' is free to act its descent, turning the shaft G³,
and bringing the arm g down into position to be acted upon by the tappet f*, and
causing the wiper h³ to bear against the cross piece k, and move the slide valve into
position to admit steam to the cylinder for the back stroke. Near the termination
of the said back stroke the tappet f* will come in contact with the arm g³, raising
the said arm, and causing the wiper h to act upon the cross piece k³, and shift the
slide valve into the position in which steam is cut off from the cylinder; the
cataract J is raised, and the quadrant i¹ brought clear of the quadrant i, which
leaves the cataract J free to descend, its descent turning the shaft G¹, and causing
the wiper h' to act against the cross piece ³, and bring the slide valve into position
for admitting steam to the, cylinder for the forward stroke.
Figure 5 is a longitudinal section, and Figure 6 a plan of a modification of the
foregoing arrangement, in which, in place of the ordinary liquid cataract, I employ
the pressure of the steam to complete the shifting of the slide valve. The spindle
of the slide valve is furnished with a piston working in a cylinder m fitted with
a valve n. Upon the short shaft p turns the lever p¹, formed with two arms p², p³,
which respectively lie in the paths of the tappets q2 and q³ upon the rod Qattached
to the piston rod of the main cylinder. The upper arm of the lever p¹ is formed
with two wipers p, p, which respectively engage with the slotted heads of the slide
valve spindle and of the spindle of the valve n.
In the Drawing the parts are represented in the positions which they occupy
when the piston rod is near or at the end of its backward stroke, the tappet q³
having by bearing upon the arm p³ turned the lever p¹, and caused the part p¹ to
act upon the slide valve spindle l, and shift the slide valve into the position in which
no steam passes to the cylinder, and when the said valve has been brought to this
position the part 2 of the lever p', acting upon the spindle of the small valve n,
shifts it into a position in which steam is admitted to the back of the small piston l'
(through the branch n¹ from the main steam pipe), and the said steam thereby
forces forward the valve spindle 1, and further moves the slide valve into the position in
which steam is admitted to the main cylinder for the forward stroke of its piston.
When the said piston is near the end of its forward stroke the tappet q³ comes into
contact with the arm p³, and causes the part pt of the lever p¹ to shift the slide valve
spindle into position in which steam is not admitted to the main cylinder, and the
part ps to shift the small valve n so that steam is admitted to the front of the
piston, whereby the slide valve is further shifted into position to admit steam to
the main cylinder for the back stroke.
In order to control and prevent the too rapid action of the slide valve its spindle
is continued beyond the steam chest at back, and terminates in a piston 12 working
in a small cylinder 13, provided at either end with valves * opening inwards, and
with exit passages 1 furnished with cocks, by which the capacity of the said
passages may be regulated. As the piston moves in one direction it draws air into
the cylinder at one end, the air at the other end acting as a cushion to regulate
by its resistance the motion of the spindle of the slide valve, the degree of resistance
which this cushion offers being regulated by contracting or enlarging (by means of

page_text: its cock) the outlet orifice 1 through which the air escapes. A like action takes
place on the reverse stroke of the slide valve spindle l.
In place of air a liquid may be substituted. Other motive power than the steam.
from the main steam pipe may be used to actuate the piston U.
Figure 7 represents in longitudinal section, and Figure 8 in plan, a modification
of the last-described arrangement, in which the lever p' is acted upon by tappets
92, 93, in the same line so as both to act upon the tail po of the said lever.
Figure 9 represents in longitudinal section, and Figure 10 in plan, another modi-
fication, in which the lever p¹, in place of being acted upon by tappets, is actuated
by the lever r jointed to an arm keyed to the piston rod of the main cylinder,
the said rod r turning upon the centre r¹ on the end of the links turning upon
pins on the standards. The other parts, as also the action of both the modified
arrangements, Figures 7, and 8, and 9, and 10 are the same as those of the arrange-
ment, Figures 5 and 6, and require no further description.
In place of the foregoing arrangements for operating the valve, what is known as
a weighted tumbling lever in combination with tappets and levers with the cataract
may be used.
Figure 10a illustrates the application of the foregoing improvements to a compound
engine.
The third part of my improvements relates to apparatus for controlling the action
of the motive agent admission valve. This arrangement is shewn in Figure 4. It
consists of a small cylinder s provided with a pair of valves s', 81, opening outwards
to the atmosphere, and with another pair of valves 82, 82, one between each end of
the cylinder 8, and another small cylinder t. Both cylinders are furnished with a
piston and piston rod. The piston 8 of the cylinders is connected through its rod
by a rod and lever 85, to the tappet rod f (or it may be to the piston rod of the
main cylinder or other convenient moving part), the lever turning upon a centre
86, on a bracket 87, and being slotted at its lower end to allow of its following the
motion of the rod f. The cylinder t is provided with a piston t', whose rod is
furnished with a spring t² whose tendency is to urge the said piston rod upward,
and raise the lever attached thereto, and open the steam admission valve u. A
regulated quantity of air is admitted to the cylinder t by the cock t*.
When the engine is at work, the piston 8 is operated, and by its action a partial
vacuum is created under the piston of the cylinder t, the extent of such vacuum
being regulated by opening or closing the cocks t so that the action of the spring
2 tending to urge the piston t upward, and the action of the vacuum tending to
draw it downward, balance each other and keep the admission valve at its proper
degree of opening.
When the engine is going at too low a speed, a less vacuum is created under
the piston t, and the spring to raises the rod of the piston t¹ and increases the
opening of the admission valve.
When the engine works at too high a speed, the vacuum created beneath the
piston t¹ is increased, and draws down the said piston and contracts the steam
inlet.
When from any accident the engine races, a vacuum is created to such an extent
that the piston t is drawn so low that a notch v in its rod comes opposite a spring
catch v', which enters the said notch and retains the said rod in this position in
which the steam is entirely cut off and the engine stops.
The fourth part of the improvements relates to the expansion and slide valve
gear of motive-power engines, and the object of this part of the improvements is to
enable the engineman to govern the speed of the engine by the expansion gear
alone, and thereby prevent the wire drawing of the motive agent.
Figure 11 is a diagram illustrating this part of the improvements. The expansion
valve handle A is mounted upon a hollow shaft B, through which passes the shaft C,
upon which the handle D of the main valve is mounted; an opening being formed
in the shaft B at b to admit of the shaft C being operated independently of the.

page_text: shaft B. This will be understood from the elevation and section of these parts,
Figures 12 and 13.
The handle A operates the expansion valve through the link motion E, and the
handle D operates the main valve through the link motion F. This arrangement
admits of the handles A and D being united by locking gear G (as illustrated in
Figure 14) and worked as one, when the engines are not working expansively or
when they are being reversed, and it also admits of the handles being worked
separately for the purpose of cutting off steam at any part of the stroke.
Figure 15 illustrates in side elevation the application of the improvement to
Cornish or crown valve hand gear for reversing or winding engines. In this gear
as ordinarily constructed, the position of the tails of the cranked levers B, upon
which the wipers C act, are adjusted (so as to be released from the action of the
wipers at the proper times) by means of screws which have to be separately adjusted
by hand.
According to my present improvement, the said levers B are adjusted by wedges
D operated through the lever d, which is actuated by the handle A through the
rod a, the said handle being carried by a socket or sleeve mounted upon or in the
shaft upon which the main valve handle is fixed. The crank levers B can thus be
simultaneously adjusted by working the handle A, so as to let the valves drop and
cut off steam at any desired position of the stroke.
Having now described and particularly ascertained the nature of my said Inven-
tion, and the system, mode, or manner in or under which the same is or may be
used or practically 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 construction and arrangement of parts for displacing the pressure of
the motive agent from the back of the slide valve of motive-power engines, essentially
as herein-before described with reference to Figures 1, 2, and 3 of the accompanying
Drawings.
Second. The arrangement for working the slide valves of motive-power engines
essentially as herein-before described with reference to Figure 4 of the accompanying
Drawings.
Third. The arrangements for working the slide valves of motive-power engines,
essentially as described with reference to Figures 5, 6, 7, 8, 9, 10, and 10ª of the
accompanying Drawings.
Fourth. The arrangement for controlling the action of the motive agent admission
valve of motive-power engines, essentially as herein-before described with reference
to Figure 4 of the accompanying Drawings.
Fifth. The arrangement of double handle and double link motion for the ex-
pansion and main valve gear of motive-power engines, essentially as described with
reference to Figures 11, 12, 13, and 14 of the accompanying Drawings.
Sixth. The arrangement of wedges for adjusting the expansion of crown or Cornish
valve gear, essentially as herein-before described, and illustrated in Figure 15 of the
accompanying Drawings.
In witness whereof, I, the said Andrew Barclay, have hereunto set my hand and
seal, this Thirty-first day of October, in the year of our Lord One thousand
night hundred and coventy night
ANDREW BARCLAY. (L.S.)