IMPROVEMENTS IN AND CONNECTED WITH SLIDE VALVES
Year: 1869

page_text: LETTERS PATENT to Walter Brock, of Glasgow, in the County of
Lanark, North Britain, Engineer, for the Invention of "IMPROVEMENTS
IN AND CONNECTED WITH SLIDE VALVES."
Sealed the 2nd October 1869, and dated the 13th April 1869.
PROVISIONAL SPECIFICATION left by the said Walter Brock at the
Office of the Commissioners of Patents, with his Petition, on the
13th April 1869.
I, WALTER BROCK, of Glasgow, in the County of Lanark, North
Britain, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN AND CONNECTED WITH SLIDE VALVES," to be as follows,
that is to say :-
This Invention is an improvement in the slide valves of steam engines,
and is applicable to the valves of any engine, but is more particularly
intended to be applied to engines where the maximum admission of
steam to the cylinders is to be comparatively short, say, when the steam
is cut off at half stroke or earlier; and the especial object of the arrange-
ment is the obtaining with any required lead of the eccentric a sufficient

page_text: area of admission for the steam of the cylinders with the shortest possible
travel of valve, combined with the means of admitting steam to the
cylinders by hand after the point of the stroke has been reached at which
the valve in ordinary working closes the admission, so as to enable the
engines to be started with certainty in either direction from any position
of rest.
It is well known that in a pair of engines arranged in the ordinary
way, where the valve gearing, such as the common link motion, is
arranged to cut off the steam at half stroke or earlier, it is necessary not
only to have a comparatively long travel of valve in order to obtain the
required area for steam admission, but also that it is necessary to have
auxiliary or starting valves or cocks workable by hand, or that the
nature of the valve gearing should be such as to admit of the main
valves being worked by hand, so as to be able to admit steam to either
end of the cylinders in order that the engines may be started from any
position with certainty.
Now this Invention consists in a peculiar form of slide valve in
combination with another valve or plate so arranged that a very large
area for steam admission can be obtained with a very short travel of
valve, and which plate is also by means of hand gearing made to answer
the purpose of a supplementary or starting valve with the additional
advantage that the attendant cannot through carelessness blow steam
through into the exhaust pipe, as with the ordinary arrangement of
starting valves.
In carrying out this Invention the admission of steam to the cylinders
is wholly or partly through passages cast in the body of the valve, and
the admission of steam to these passages and thence into the cylinder
is controlled by means of a plate or valve of any convenient form, flat,
circular, or otherwise curved, having passages or openings cast in it for
this purpose. These openings and those in the main valve are in number
more or fewer accordingly as it is desired to have less or more travel of
the main valve. This plate or valve is stationary during the ordinary
working of the engine, but is connected to hand gear by which it can
be moved in any convenient direction whilst in contact with the main
valve, or so as to admit steam to the end of the cylinder where it is
required for starting the engine at a point of the stroke later than that
at which the steam is cut off when the plate is in its normal or working
position. In the case of very large engines it is not intended to move the

page_text: entire valve or plate, but in such cases it would be constructed in two or
more pieces, one of which would be connected to hand gear and used
as a starting valve as aforesaid.
This Invention is very applicable to that class of compound engines
having one high-pressure and one low-pressure cylinder working on
cranks at or nearly at right angles to each other, in which it is generally
desirable that the steam should be cut off in both cylinders earlier than
at half stroke.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Walter Brock in the Great Seal Patent Office on
the 12th October 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WALTER
BROCK, of Glasgow, in the County of Lanark, North Britain, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirteenth day of April, in the year of
our Lord One thousand eight hundred and sixty-nine, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Walter Brock, Her special licence that
I, the said Walter Brock, my executors, administrators, and assigns, or
such others as I, the said Walter Brock, my executors, administrators,
and 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 AND CONNECTED WITH
SLIDE VALVES," upon the condition (amongst others) that 1, the said
Walter Brock, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, 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 Scal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Walter Brock, do hereby declars
the nature of my said Invention, and in what manner the same is to

page_text: be performed, to be particularly described and ascertained in and by the
following statement in writing, reference being had to the accompanying
Drawings, that is to say :-
My said Invention relates to the slide valves of steam engines, and is
applicable to the valves of any engine, but it is more particularly
intended to be applied to engines where the maximum admission of
steam to the cylinders is to be comparatively short, say, when the steam
is cut off at half stroke or earlier; and the especial object of the main
part of my improved arrangements is the obtaining, with any desired
lead of the eccentric, a sufficient area of admission for the steam to the
cylinders with a very short travel of valve, combined with provision for
admitting steam to the cylinders by hand after the point of the stroke
has been reached at which the valve in ordinary working closes the
admission, so as to enable the engines to be started with certainty and
convenience in either direction from any position of rest.
It is well known that in a pair of engines arranged in the ordinary
way, where the valve gearing, such as the common link motion, is
arranged to cut off the steam at half stroke or earlier, it is necessary not
only to have a comparatively long travel of valve in order to obtain the
requisite area for steam admission, but also to have auxiliary or starting
valves or cocks, workable by hand, or that the valve gearing should be
arranged so that the main valves can be worked by hand.
Now my Invention consists mainly in a peculiar form of slide valve in
combination with another valve or plate, and so arranged that a very
large area for steam admission is obtained with a very short travel of
valve, whilst the plate is also made to answer the purpose, amongst
others, of a supplementary or starting valve, with the additional advan-
tage that the attendant cannot through carelessness blow steam through
into the exhaust pipe, as with the ordinary arrangement of starting
valves.
And in order that my said Invention and the manner of performing
the same may be properly understood I have hereunto appended two
Sheets of explanatory Drawings, to be herein-after referred to, and
representing some of the various modifications of which my improved
arangements are susceptible. In these Drawings the same reference
numerals are used to mark the same or like parts in all the Figures in
which they occur.

page_text: Figures 1, 2, and 3, on Sheet 1 of the Drawings, are different views of
a slide valve arranged according to my Invention, Figure 1 being a
vertical section as through the port face; Figure 2, a cross section at
right angles to Figure 1; and Figure 3 a face view, 1, 2, 3, being the
usual steam and exhaust passages of a cylinder. The valve 4 is con-
structed as usual, excepting that two passages 5, 6, are formed through
it. The admission of steam to these passages is controlled by the valve
or plate 7, which when the engine is at work is stationary. This plate
overlaps the passages 5, 6, towards the centre of the valve 4 by
distances 8, which correspond and are equal in length to the "cover"
or "lap" 9 of the main valve 4. When the main valve is at either
extremity of its travel the corresponding passage 5 or 6 will be opened
to receive steam to the same extent that the cylinder passage 1 or 2 is
uncovered by the outside lap of the main valve, and therefore an admis-
sion for steam to the cylinder passage is obtained twice as great as is
obtained from an ordinary valve with the same stroke and cover. It is
therefore obvious that for any required area for and duration of steam
admission a very much shorter travel of valve will suffice with this
arrangement than could be used with an ordinary slide valve. If the
cover 9 of the main valve 4 is made long enough, so that all the steam
must pass to the cylinder by the passages 5, 6, only, these passages being
enlarged for this purpose, and made to communicate each with two or
more openings in the back of the main valve, all being controlled by
ย plate or plates 7, as described, it will follow that accordingly as these
openings are made more or fewer so the required length of travel for any
opening and period of admission will be less or greater.
Figure 4 shows an example of this modification, wherein each
passage 5, 6, has three openings or ports in the back of the main valve 4.
The valve or plate 7 (Figures 1 to 4) is connected to a spindle 10, com-
municating by means of a link 11 with a hand lever 12, by moving
which steam can be admitted by means of the passages 5, 6, to the end
of the cylinder, where it is required for starting the engine at any point
of the piston's stroke later than that at which the main valve closes the
passages 1, 2, up to nearly the very end of the stroke, the part of the
valve at a, where it overlaps the cylinder passages 1, 2, being made very
small in order that that may be done. The plate 7 is made so as to be
free to move off its face, being merely held thereto by a light spring 13,
so that this plate will answer all the purposes of an escape valve. It is

page_text: especially intended to make use of it in this capacity when applied to
the low-pressure cylinder of a compound engine. In these cylinders,
when the steam is cut off at or before half stroke by the ordinary or this
arrangement of slide valve, there is a considerable amount of "com-
pression," which as regards the smooth working of the engine is a
benefit, but on starting before a vacuum is formed in the condenser, and
when there is consequently air or steam of at least atmospheric pressure
to compress, the pressure caused by the compression may become greater
than the ordinary maximum working pressure in the cylinder, and
acting on the large area of the low-pressure cylinder impede the starting
of the engine, unless the compressed air or steam is allowed to escape
through the ordinary escape valves. Now the plates 7 will yield to the
compression as soon as it becomes greater than the pressure in the valve
casing, and the compression will be thereby relieved without the steam
blowing into the engine room.
Figures 5, 6, and 7 show the same parts as in Figures 1, 2, and 3, but
with the supplementary valve or plate 7 arranged differently. In this
example the valve 7 is attached at one side to a spindle 14, and at the
other side it is held between shoulders formed on a spindle 10, the part
of which where it is embraced by the valve or plate being formed
eccentrically, as shown at 15. This spindle 10 passes through a stuffing
box at one end, and has a hand lever 12 attached to it. By this arrange-
ment it will be seen that by turning the spindle 10 by means of the
hand lever the valve or plate 7 will be turned on the spindle 14 as a
centre, and lifted off the back of the main valve 4 in the manner of a
door, thereby admitting steam to the passages 5, 6. This arrangement
will also act as an escape valve, the plate rising whenever the pressure
below it becomes great enough to overcome the pressure in the casing
and the light springs 13.
Figures 8 and 9 show another arrangement of the supplementary
valve or plate 7 especially intended for large-sized engines. In this
example it is made in two pieces, one, 16, being considerably smaller
than the other, and connected as before to the lever 12 by means of the
spindle 10 and a link.
Figures 10, 11, and 12 show another arrangement in which a part of
the plate 7 is fitted with a small curved valve 16 attached to the
spindle 10 and hand lever 12, by which it can be turned round to admit
steam to the passages 5, 6.

page_text: In Figures 13, 14, and 15 the valve or plate 7 is represented as
attached to the fixed spindle 17, by which it is held in place, and it
has formed in it two recesses 18 in communication with each other by
the passage 19. These recesses and the passage 19 form an internal
cavity, which is closed by a valve 20, attached to a spindle 10, link 11,
and hand lever 12, as before. The valve 20 is kept closed by a light
spring 13. By opening the valve 20 steam is admitted to the interior
of valve 7, and thence by the passages 5, 6, to the end of the cylinder,
where it is required for starting, as already described. It will be seen
also that the valve 20 will act as an escape valve for the cylinder, as
also already described.
Figures 16, 17, and 18, on Sheet 2 of the Drawings, show an
arrangement similar to that last described, but having the cut-off plate
or valve 7 in the form of a piston valve.
Figures 19 and 20 show my Invention as applied to a valve having a
double-ported valve face of a common kind. In this example each
passage 5 or 6 has three steam ports or openings in the back of the main
valve 4, with a suitably formed valve or plate 7. This plate is attached
to two spindles or bars 21, which are in effect springs made so as to
have a tendency to lift the plate 7 off the main valve 4. On the back of
the plate 7 there is applied a spring 13, acted on by the screw 22 and
hand wheel 23. When the engine is at work this valve 7 is kept in
contact with the main valve 4 by means of the screw 22, but when it is
required to start the engine, or when it is necessary to frequently start
or stop, the hand screw 22 is unscrewed, allowing the plate 7 to rise off
its face by the action of the spindles 21, thereby allowing the main valve
to give steam until very nearly the end of the piston's stroke, and also
preventing the compression becoming greater than the pressure in the
valve box.
My Invention is very suitable for the class of compound engines in
which one high-pressure cylinder and one low-pressure cylinder are
connected to cranks at or nearly at right angles to each other, and in
which it is generally desirable that the steam should be cut off in both
cylinders earlier than at half stroke.
In the various examples herein-before described my Invention is
shown as applied to unbalanced slide valves, but it is also obviously
applicable to various forms of equilibrium or balanced valves.

page_text: Having thus particularly described my said Invention, and the manner
in which the same is to be performed, 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 the herein-before in part recited Letters Patent is,―
1. The constructing of slide valves with passages for the entering
steam or part of it, and controlling the admission of steam to these
passages by plates or valves on the main valve, these plates or valves
being stationary during the ordinary working of the engine, but movable
by hand, so as to admit steam when otherwise cut off, substantially as
herein-before described.
And, 2. The using of non-reciprocating plates or valves on the main
valve, or a valve in such plates as a relief valve, substantially as herein-
before described.
In witness whereof, I, the said Walter Brock, have hereunto set
my hand and seal, this Eleventh day of October, in the year of
our Lord One thousand eight hundred and sixty-nine.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
WALTER BROCK. (L.S.)