Improvements in Steam Engines.
Year: 1899

page_text: lication 7th Dec., 1899-Accepted,
lication 7th Dec., 1899-Accepted,
5
COMPLETE SPECIFICATION.
Improvements in Steam Engines.
, JAMES HARRY KEIGHLY MCCOLLUM, of 75, Howland Avenue, in the City of
ronto, in the County of York, in the Province of Ontario, Canada, Electrician,
hereby declare the nature of my invention and in what manner the same is to
performed to be particularly described and ascertained in and by the following
atement:
My invention relates to improvements in steam engines and the object of the
vention is to provide a simple, cheap, efficient and advantageous arrangement
f valves whereby boiler pressure steam may be used full stroke or cut-off, so
s to obtain expansion to any degree yet having wide open large ports for
entrance and exit from the cylinder and also to have the opening and closing of
all ports take up as little time during the stroke as possible and all ports to
remain wide open during as much of the stroke as possible, thereby entirely
doing away with the squeeze-off action and yet providing at all times the necessary
cushion for the piston and it consists essentially of a steam chest provided with a
valve casing or cylinder and a series of valves connected to a rod and designed
to be operated in the valve casing by an eccentric or crank and in conjunction
with the inlet and exhaust ports leading from the valve casing to the cylinder
and the divided ports leading from the valve casing to the steam chest, the size
of the latter openings being regulated by two recessed slide valves operated
preferably by the right and left hand threaded rod in the manner hereinafter
more particularly explained.
Fig. 1, is a longitudinal section through the cylinder and valve chest.
Fig. 2, is a longitudinal section showing an alternative arrangement of valves
suitable for an engine when the steam and exhaust ports and valves are separate.
In the drawings like letters of reference indicate corresponding parts in each
figure
A is the cylinder and B the piston and C the piston rod. D is the steam
chest. E is a valve casing located in the steam chest adjacent to the cylinder
and e and 2 are the inlet and exhaust ports and e' the exhaust. The casing
30 is preferably cylindrical as shown.
FF are two ports extending through the casing E and provided with
G is a spindle or rod, which extends through the steam chest I
divisions f
with suitable packing at the ends thereof and is provided with a grooved collar
into which a fork g extends, so as to hold the rod in place longitudinally whe
35 it is turned as will hereinafter appear.
The rod G is provided with a hand wheel G', and also provided with a rig
and left hand thread inside the steam chest on which are placed the valves
and H having the recesses h adjacent to the valve casing. I is a valve rod
stem, which is provided at one end with the cylindrical valves J and J¹ and
40 the opposite end with the cylindrical valves J³ and J³.
:
It will be noticed that in the position shown in the drawing t
valve is shown at the right hand, end of the casing, the valve
to the left of the part F1, the valve Je half on to the exha

page_text: port el and the valve J³ mostly covering the port F. The valve rod I is of course
worked from an eccentric on the main shaft of the engine (not necessary here to
describe) and the various positions, which I describe are those which the valves
assume in the operation of my engine. The valves H and H¹ are set, so as to
cover most of the ports F and F leaving the outer ends of the ports in each
instance uncovered."
The rod I is first thrust by the eccentric in the direction indicated by arrow.
When the eccentric has thrown the rod, so as to bring the valves J J1 J2 J3 into
the position shown by full lines in Fig. 1, the steam is entering through the
reduced port F1 into the valve casing but is entirely shut out from entering
the port by the valve J3 at the opposite end. When the rod I is moved along a
little farther by its eccentric into the position shown by light dotted lines, that is
to say with the inner end of the valve J opposite the outer end of the valve H¹,
it will be seen that the steam is entirely shut off from the steam chest and
cylinder, but passes through the divided port F into the recess h, such steam
being located between the valves J J and H¹ As the valve rod I pushes the
valves a little farther along the valve J passes the port e and opens the same in
time to allow steam to cushion the piston no matter whether boiler pressure steam
is used full stroke or used expansively to any degree. At the opposite end the
valve J2 would be passing the port e in order to allow of the exhaust to pass up
between the valves J and J and into the exhaust port el, the space between
the valves J and J serving the same purpose as the cavity in the common flat
slide valve. The rod I would still be carried in the direction indicated by
arrow by the eccentric until the valve J reaches the position shown by heavy
dotted lines, when the reverse motion of the eccentric would start to carry it
back into the position shown in light dotted lines. It will thus be seen that
the expansion of the steam would be permitted through a maximum space of
time. During this movement of the valve J the valve J keeps the port F' closed.
Simultaneously with the movement of the valve J, the valves J and J³ move
and present a space in the valve casing to receive the steam from the chest
through the port F. It is not necessary here to describe anything further in
reference to the valves J2 and J³ as they act exactly the same as the valves J.
and J.
It will thus be seen that when the auxiliary and main valves are controlling
the steam, so as to obtain the best advantage by expansion, the steam is admitted
through a wide open port from the steam chest into the valve casing, then as
the main valve moves along communication is cut off between the valve casing
and steam chest before communication is opened between the valve casing and
cylinder, and when communication is opened between the valve casing and
cylinder the only steam that passes into the cylinder is that which was contained
between the auxiliary and two end main valves. This space is of such a size in
comparison with the cylinder that the steam at boiler pressure in this space
when let into the cylinder drops to as low a pressure as it is practical to work
it when the piston reaches the end of the stroke. It will also be understood
that no steam can be locked in any of the passages of the port F1 by the valve J¹
near beginning of the piston stroke and liberated so as to enter the cylinder
near end of the same as any steam kept from escaping from the port F¹ passages
by valve J can escape through the recess h and other port F passages into
cylinder. The stroke of the valve rod I is such in conjunction with the stroke of
the piston that the steam is allowed to give cushion and to perform its other
functions to the best advantage at all times.
When the valve J reaches the position to cover the port e of course the exhaust
is closed and the operation of the valve is repeated.
It is well known in steam engines of the slide valve type that when same are
running as efficiently as it is possible to run them, that the inlet and outlet &
passages or ports for the steam have to be cramped to a great degree to keep
from using boiler pressure full stroke. By my arrangement of valves and ports

page_text: is cramping of the steam is entirely done away with anu
d much greater efficiency obtained.
Of course in my engine by manipulating the rod G I can so adjust the valves H
ad H' so that the engine may be started and run under a full head of steam or
all boiler pressure for full stroke and then brought into the ordinary running
osition shown in the drawing using steam by expansion to best advantage or if
esired boiler pressure steam can be used any part of the stroke and expansion
he remainer.
In Fig. 2, in which I show a type of engine with separate exhaust and inlet
alves and ports, it will be noticed that it is necessary only to provide one large
livided port F2 from the steam chest into the valve casing. I also adjust the
alves H and H' as indicated and provide a rod I with two valves J and J³ to
control the steam entering into the cylinder and a valve J6 to control the entrance
of the steam from the steam chest into the valve casing. The operation is
equivalent to that which has been before described.
I also provide preferably at the opposite side of the cylinder a valve casing E
and separate exhaust ports e³ and et connected to the casing from which an
exhaust pipe e leads. I provide within the casing 2 the valves J and Js, which
are connected to the rod 12. This rod 12 is connected to another eccentric from.
that to which the rod I is connected. The two eccentrics are used in this type
of engine, one to work the steam or inlet valves and the other to work the exhaust
or outlet valves, the space between the valves J and J8 serving the same purpose
as the cavity in the ordinary slide valves. The difference of position of the
eccentrics operating the inlet and exhaust valves is such as is found best for the
proper entrance and exit of steam from the cylinder.
It will be noticed that in the form described in Fig. 2, that I have to use
separate steam and exhaust valves and two valves for the inlet ports in the
cylinder but only one for controlling the steam passing from the steam chest
into the valve casing but the principle of action is exactly the same.
Although in this specification I describe the valves as cylindrical or piston,
it will be understood that flat or other slidable valves can be used and operated.
Of course any of the valves shown may be made of any suitable form adaptable
for the purpose designed without departing from the spirit of my invention.
Having now particularly described and ascertained the nature of my said
5 invention; and in what manner the same is to be performed, I declare that what
I claim is
1. In a steam engine, the combination with the cylinder and piston and inlet
ports and exhaust ports, of the steam chest, the valve and openings connecting
with the cylinder inlet and exhaust ports and openings communicating with
10 the steam chest, said valve deriving a reciprocating movement and controlling
the admission of steam from the steam chest into the cylinder ports and the
auxiliary controlling valves located outside of the main valve and designed to
control the size of the openings communicating with the steam chest as and for
the purpose specified.
45
2. In a steam engine, the combination with the cylinder and piston and inle
ports and exhaust ports, of the steam chest, the valve casing having opening
connecting with the inlet and exhaust ports and openings in the casing communi
cating with the steam chest, the valves and valve rod deriving a reciprocatin
movement in the casing and controlling the admission of steam from the stea
50 chest into the casing and from the casing into the cylinder ports and from th
cylinder ports into the exhaust ports and the valves located outside the casin
in the steam chest and designed to control the size of the openings leading in
the valve casing and means for manipulating such valves as and for the purpo
specified.
55
3. In a steam engine, the combination with the cylinder and piston and in
norts and exhaust ports, of the steam chest, the valve casing having openin

page_text: connecting with the inlet and exhaust ports and openings in the casing com-
municating with the steam chest, the balanced valves and valve rod deriving a
reciprocating movement in the casing and controlling the admission of steam
from the steam chest into the casing and from the casing into the cylinder ports
and from the cylinder ports into the exhaust ports and the valves located outside
the casing in the steam chest and designed to control the size of the openings
leading into the valve casing, a rod extending through the steam chest provided
with a right and left hand thread extending through a corresponding threaded
opening in the valves, a collar on the rod and a fork extending into the collar,
EO as to permit of the rotation of the rod without longitudinal displacement as
and for the purpose specified.
4. In a steam engine, the combination with the cylinder and piston and inlet
ports and exhaust ports, of the steam chest, the cylindrical casing having
openings connecting with the inlet and exhaust ports and divided openings in
the casing communicating with the steam chest, the balanced cylindrical or
piston valves and valve rod deriving a reciprocating movement in the casing
and controlling the admission of steam from the steam chest into the casing
and from the casing into the cylinder ports and from the cylinder ports into
the exhaust ports and the valves located outside the casing in the steam. chest
and recessed as shown and designed to control the size of the openings leading
into the valve casing and means for manipulating such valves as and for the
purpose specified.
Dated the th 1
1000
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.