Improvements in or connected with Valves for Steam Engines.
Year: 1891

page_text: Date of Application, 26th June, 1891
Complete Specification Left, 26th Mar., 1892-Accepted, 30th Apr. 1892
PROVISIONAL SPECIFICATION.
Improvements in or connected with Valves for Steam Engines.
I, JOHN THOM, of Inverkip, in the County of Renfrew, Engineer, do hereby
declare the nature of this invention to be as follows:-
The improvements in valves for steam engines, the subject of the present
invention, concern more particularly valves working in the manner such as
described in the 'Specification of foriner Letters Patent granted 'to me No. 4087,
A.D. 1883. In the invention, the subject of my said former Patent, I conveyed
the 'steain from one side of the piston of the cylinder at the end of each stroke
for re-use at the other side of the piston, by leading the steam through a passage
in the valve and arranging the ports so 'that a communication is opened between
the ends of the cylinder at the end of the stroke.
According to my present invention, I construct the valve with a connecting
passage or passages and ports in the side or sides and ends, or in the centre of
the valve, instead of 'making the whole back of the valve double. The valve is
thus lighter and stiffer, not so liable to hog, and a much simpler casting to make.
The valve can be arranged for single, double, treble, or more ported cylinders.
The communicating passages can be arranged down the centre, and also round
the sides of the valve, and the steam can be let in from the back of the valve
through a passage to an inside port or ports.
Dated this 25th day of June 1891.
CHEESBROUGH & ROYSTON,
15, Water Street, Liverpool, Applicant's Patent Agents.
'COMPLETE SPECIFICATION.
Improvements in or connected with Valves for Steam Engines.
I, JOHN THOM, of Inverkip, in the County of Renfrew, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:—
The improvements in valves for steam engines, the subject of the present
invention, concern more particularly valves by which steam from one side of the
piston of the cylinder conveyed to the other side of the piston at the end of each
stroke, and compressed, and re-used upon the piston, the conveyance of steam, as
heretofore effected, being carried through a passage in the back of the valve, and
by so arranging the ports thereof that a communication is thereby made at the
required time.
According to my present invention, I construct the valve with a connecting
passage or passages and ports in the side or sides and end, or in the centre of
the valve, instead of making the whole back of the valve double. The valve is
thus lighter and stiffer, not so liable to hog, and a much simpler casting to make.
The valve can be arranged for single, double, treble, or more ported cylinders.
The communicating passages can be arranged down the centre, and also round
the sides of the valve, and the steam can be let in from the back of the valve
through a passage to an inside port or ports.
In the various drawings which serve to illustrate my invention, I shew some
Fexamples of constructions of valves with my present improvements applied thereto.
Pill

page_text: Figure 1 is a sectional elevation; Figure 2 a sectional plan, and Figure 3 a
cross section of a valve according to this invention.
Figure 4 is a longitudinal section of a double ported inlet and double ported
exhaust valve according to this invention.
Figure 5 is a cross section of same through the centre of the valve.
Figure 6 is a longitudinal section, and
Figure 7 is a cross section of a valve according to this invention, adapted to
exhaust through the back thereof.
Figure S is a sectional elevation of a double ported cylinder and valve according
to this invention adapted to admit steam through four inlets; and Figure 9 is a
cross section of the valve taken half at the line A B and half at the line C D
Figure 8.
Figure 10 is a longitudinal section of valve according to this invention and
double ported cylinder face, the valve being adapted to admit steam from the
back and Figure 11 is a cross section half at the line A B and half at the
line C D Figure 10.
Figure 12 is a longitudinal section of valve and cylinder port face according to
this invention adapted to admit steam to the cylinder through three inlets, and to
exhaust through two outlets; and Figure 13 is a cross section of the valve half at
the line A B and half at the line C. D. Figure 12.
Figure 14 is a longitudinal section, and Figure 15 is a cross section of a valve
according to this invention and cylinder port face adapted to admit steam at three
points to the cylinder and to exhaust at two points of the communicating passage.
Figure 16 is a longitudinal section of a valve and cylinder port face according to
this invention wherein the communicating passage in the valve forms communi-
cation between the two inner ports of the cylinder port face; Figure 17 is a
sectional plan of same; and Figure 18 is a cross section of the valve taken half at
the line A B and half at the line C D Figure 16.
Figure 19 is a longitudinal section of my improved valve arranged as in
Figures 16, 17 and 18, in a modified manner.
Figure 20 is a longitudinal section of the valve and cylinder port face adapted to
admit steam at two points or inlets and to exhaust at two, the communicating
passage being provided at each side; and Figure 21 is an end view partly in
section, of same.
Figure 22 is a longitudinal section of my valve with a cylinder port face adapted
to admit steam through two passages and exhaust at one; and Figure 23 is a cross
section of same.
In the drawings, the same letters and figures of reference are used throughout to
denote the same or equivalent parts wherever they occur.
In the drawings. V designates generally the valve, a is the cylinder face having
ports, b, c, and d, d being the exhaust port: e is the passage through the valve by
which steam is carried from one end thereof to the other, and e¹, e² are the walls
forming or enclosing the said passage; are pockets in the valve forming steam
passages and ports therein.
In the drawings of valves illustrating this invention,.negative lap of the inner
edge of the passage e, and a small amount of positive lap of the bars according to
my former Patent No. 14957 of 1889, are provided and shewn in most cases, that
is to say, the bars f of the valve are of such a width relatively to the width of the
ports and so arranged in relation thereto, that at the time communication between
the opposite ends of the cylinder, by way of the passage e, is first made, steam from
the cylinder will thereby be free to How momentarily to the exhaust port d;
but the invention is not in any way confined to valves of this particular con-
struction as it has reference to all valves whereby steam is transported from one end
of the cylinder to the other.
In the valve shewn in Figures 1, 2, and 3, the passage e runs through the centre
portion of the valve, and at each end spreads out into the full width of the valve.at
right angles to the through passage.

page_text: In Figures 4 and 5 the passage e is divided in two, and rums also through the
valve longitudinally, and opens out into a transverse passage at each end across the
whole width of the valve.
In Figures 6 and 7 the passage e is also divided and is carried through the valve
on either side thereof as shewn, but spreading out the full width of the valve at
each end on the face so as to correspond with the cylinder port face. The exhaust
in this case takes place through the back of the valve, through the passage d.
From
these two examples it will be plain the passage e may be disposed anywhere within
the valve longitudinally, so long as it does not interfere with the steam exhaust
ports of the valve. A valve therefore, provided with this improvement with respect
of the passage e may be made practically of the same size and weight as an ordinary
slide valve, and given the same amount of port opening, whereas in valves heretofore
constructed with "trick"passage for the purpose of conveying steam from one
end of the cylinder to the other, as well as for supplying steam from the valve box,
the size and weight of such valve is greater than the ordinary valve, and the
expansion of the double back frequently causes hogging of the valve, and in itself
is difficult to make, and is costly.
In Figures 1, 2; and 3 steam is admitted to the cylinder ports by three inlets, one,
over the end of the valve, one through the passage e, and the third through the
pocket and port h.
In the arrangement shewn in Figures 4, 5, 6 and 7, the second ports as in
Figures 1 to 3 are not provided, a bar being adapted to cover and uncover the
exhaust port, ce, at the proper times.
With reference to Figures 8 and 9, the passage e is carried through the centre of
the valve, and the arrangement shewn provides for four inlets for steam, namely,
one inlet to the cylinder ports is by way of the passage e, another is past the edge.
of the valve, another is by way of the steam pockets and ports, and the fourth is,
by way of an inner passage e which passes round the throat of the exhaust outlet"
of the valve, at the side, as shewn in Figure 9. Steam is admitted to these ports
or passages from the passage m which opens into the steam space in the valve chest at.
one or both sides thereof.
In the modification shewn in Figures 10 and 11, the communicating passage e'
lies within the central portion of the valve and communicates with the inner ports c
of the cylinder port face a so that steam is transported from one port e to the other,
by way of the passage.
In this construction also steam is admitted to the cylinder
over the ends of the valve and also by way of the spaces and ports from the back
of the valve, in lieu of two inner pockets or ports as set forth with reference to
Figures 1 to 3 and 8 and 9.
In Figures 12 and 13, the communicating passage e runs from end to end of the
valve at the sides as shewn spreading out at the ends in a transverse port, as already
described with reference to Figures 1 to 7 and others, whilst steam is admitted to
the cylinder through the pockets and ports from the back of the valve as in
Figures 10 and 11, as well as through the passage e and over the ends of the valve.
In the modification shewn in Figures 14 and 15, the passage e for communicating
between the opposite ends of the cylinder is divided as shewn and carried partly,
over the back of the valve at each side and the nut and collar of the valve'
spindle n lie within the space between the divided passage e at each end (as also.
in Figures 12 and 13). The length of said spindle is thereby reduced. Steam
enters the cylinder ports in this case in three ways, namely, over the end of the
valve, through the port or passage e, and through the pockets and ports h.
+
With reference to Figures 16, 17 and 18, the communicating passage e is disposed.
within the central part of the valve and communicates between the two inside"
ports c c of the cylinder face a as shewn, as in Figures 10 and 11, in lieu of the
outside ports bb. The advantages of this modification are that the capacity of
the passage e forming the communication is less than when said passage runs from
end to end of the valve, and less travel of the piston is necessary to compress steam

page_text: in this arrangement. A further advantage is that the steam has a shorter distance
to travel when being transported; also the valve does not require to be any larger
than an ordinary valve and suits the ports of the cylinder as arranged for ordinary
slide valves, there being generally an excessive space in the exhaust port of a slide
valve in which the communicating passage in this case is disposed.
The passage arranged as in these figures can be adapted to serve for an inlet of
steam also, if desired, provided a passage or recess be inade in the cylinder face to
admit steam, as is done in Figure 8 and designated m. In cases where this is done,
this arrangement provides for double amount of steam opening as compared with
the ordinary double ported steam valve.
In the modification of the arrangement described with reference to Figures 16, 17
and 18 shewn in Figure 19, the inside edge of the metal forming the inner wall of
the passage does not necessarily touch the cylinder port face a as it is not
necessary that the edge of this part should be a close fit with the cylinder port face,
although the communication between ends is more perfect when it is a close fit,
but the exhaust is freer when it is not a close fit.
Figures 20 and 21 shew a valve according to this invention with the passage e
running through the valve on each side, and steam enters the cylinder by way of the
passage e and past the end of the valve. The difference between this valve and
that shewn in Figures 4 and 5 is that the transportation of steam takes place through
the passages e at the side of the valve instead of through the centre of the valve as
set forth with reference to those figures.
Figures 22 and 23 shew a valve whereby steam enters by the passage e and past
the end of the valve, and exhausts by a single exhaust port, the communicating
passage e running through the valve at the side as shewn. This arrangement of
valve could also be used instead of the ordinary valve without forming a communi-
cation between the ends of the cylinder, as it is easier made.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed declare that what I
claim is
1. In valves for steam engines providing a passage or passages therein for
conveying steam from one end of the cylinder to the other, through said valve at the
side or inner part thereof, substantially in the manner and for the purposes herein
set forth.
2. The valve arranged and constructed and adapted to operate substantially as
set forth with reference to Figures 1 to 3 of the drawings.
3. The valve constructed and adapted to operate as set forth with reference to
Figures 4 and 5 and 20 and 21 of the drawings.
4. The valve constructed and adapted to operate as set forth with reference to
Figures 6 and 7 of the drawings.
5. A valve having a communicating passage e adapted to communicate with the
inner ports of a cylinder port face wherein two or more sets of ports are employed,
substantially as and for the purposes set forth.
6. The valve constructed and adapted to operate substantially as set forth with
reference to Figures 8 and 9 of the drawings.
7. The valve constructed and adapted to operate substantially as set forth with
reference to Figures 10 and 11 of the drawings.
8. The valve constructed and adapted to operate as set forth with reference to
Figures 12 and 13 of the drawings.
9. The valve constructed and adapted to operate as set forth with reference to
Figures 14 and 15 of the drawings.
10. The valve constructed and adapted to operate as set forth with reference to
Figures 16, 17 and 18 of the drawings.
11. A valve having within it a passage e with the inner walls of its ports

page_text: constructed so as not to touch the cylinder port face; substantially as set forth with
reference to Figure 19 of the drawings.
12. The valve constructed and adapted to operate as set forth with reference to
Figures 22 and 23 of the drawings.
Dated this 25th day of March 1892.
CHEESBROUGH & ROYSTON, Fellows Chart. Inst. P.A.,
15, Water Street, Liverpool, Applicant's Patent Agents.