Year: 1897

page_text: I, PETER THORNLEY, of Alton Villa, Shobnall Street, Burton-on-Trent, in the
County of Stafford, Engineer, do hereby declare the nature of this Invention to be
Bs follows:-
This invention consists of the herein described improvements in those slide valves
for steam engines in which a cut off or expansion slide valve is arranged to work
on the back face of the main slide valve, the stroke of the cut off or expansion
valve being controlled by the governor which automatically varies the point of cut
off. By my Invention the pressure of the steam on the cut off valve is reduced to a
minimum and the steam port is opened quickly for the inlet of the steam and cut
off sharply at various points of the stroke as controlled by the governor. The
indicator diagrams obtained from a cylinder working with my Invention are equal
to or almost equal to the diagrams obtained from an engine cylinder fitted with
Corliss valve pear.
In carrying out this Invention the main slide valve has two steam inlet ports o:
passages as usual, but instead of the space in the back of the main slide valve
between the two steam inlet ports therein being a solid facing as is usual, I
provide in this central part of the main slide valve, a central steam inlet passage
which opens out at and receives steam from the top and bottom of the main slide
valve. I make the expansion valve or cut off valve with two interior chambers
divided by a vertical cross rib, one of these chambers corresponding with one of the
steam inlet ports in the main valve and the other chamber corresponding with the
other steam inlet port in the main valve. When one outside edge of the cut off
or expansion valve opens the steam inlet port in the main slide valve in the usual
way, the central internal rib of the expansion valve uncovers the said central
steam inlet passage so that the port in the main slide valve will then receive steam
from the central steam passage within the expansion valve as well as from the
outside edge of the expansion valve. Thus the area of the opening of the steam
port of the main slide valve will be twice as great as when the expansion valve is
made solid in the usual way, and there is no central steam inlet in the main valve.
I thus effectually avoid any wire drawing of the steam and get the full pressure of
the steam on the piston immediately the valve opens.
In the same way when the valves are working in the opposite direction to cut off
the steam I obtain a very sharp cut-off as the expansion valve cuts off with its
outside edge against the edge of the steam port in the usual way and at the same
time the internal rib of the expansion valve cuts off the steam at the edge of the
central steam passage.
Deted this 30th day of January 1897
CHARLES BOSWORTH KETLEY,
Agent for the Applicant.

page_text: Certain improvements in Sude Valves 1or Steam Login.
I, PETER THORNLEY, of Alton Villa, Shobnall Street, Burton-on-Trent, in the
County of Stafford, 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:-
This invention consists of the herein described improvements in those slide 5
valves for steam engines in which a cut off or expansion valve is arranged to work
on the back face of the main alide valve, the stroke of the cut off or expansion
valve being controlled by the governor which automatically varies the point of cut
off. By my Invention the pressure of the steam on the cut off valve is reduced to a
minimum and the steam port is opened quickly for the inlet of the steam and cut 1
off sharply at various points of the stroke as controlled by the governor. The
indicator diagrams obtained from a cylinder working with my Invention are equal
to or almost equal to the diagrams obtained from an engine fitted with Corliss
valve gear.
I will describe my invention by referring to the accompanying drawings on 1
which Fig. I is a sectional plan of part of a steam engine cylinder with the slide
valves constructed according to my Invention; Fig. 2 is a part sectional elevation
of the same with the expansion valve or cut off valve removed; Fig. 3 shews a
cross section of the same; Fig. 4 is a back view, Fig. 6 is a sectional plan and
Figs. 6 and 7 are cross sections of the main slide valves; Fig. 8 is a back elevation, 2
Fig. 9 is a sectional plan and Fig. 10 is a cross section of the expansion valve.
The same letters of reference indicate the same or corresponding parts in all the
Figures of the drawings.
In carrying out this Invention the main slide valve A has two steam inlet ports
or passages a¹ a³ as usual, but instead of the space at the back of this main slide 2
valve A between the two steam inlet ports a' therein being a solid facing as is
usual, I provide in this central part of the main slide valve A a central steam
passage which opens at its ends and there receives steam from the top and
bottom of the main slide valve A, that is to say, the steam from the steam chest B
enters the top end of the central passage as as indicated by the arrows in Figs. 2 3
and 3, through the open ends of the passage which is formed between the
facing and the facing on the upper wall of the steam chest B, and in the same
way the lower open end of the central passage a³ receives steam through the open
ends of the passage b' which is formed between the facings on the bottom wall
of the steam chest B as indicated by the arrows in Figs. 2 and 3. I make the 3
expansion valve or cut off valve with two interior chambers marked divided
by a vertical cross rib one of these chambers namely el corresponding with the
steam inlet port in the main valve A and the other chamber corresponding
with the other steam inlet port a in the main valve A.
When one outside edge say the left hand edge marked of the expansion 4
valve Copens the steam inlet port of the main slide valve A in the usual way
to admit steam to the back of the piston the central internal rib of the expan-
sion valve (uncovers the central steam inlet passage a so that the port a' in the
main slide valve A will then receive steam from the central steam passage within
the expansion valve C as well as from the outside edge of the expansion valve C.
Thus the area of the opening, of the steam port a' of the main slide valve will be
twice as great for a certain movement of the expansion valve C as when the expan-
sion valve is made solid in the usual way and there is no central steam inlet in the
main valve. I thus effectually avoid any wire drawing of the steam and get the
4

page_text: full pressure of the steam on the piston immediately the valve opens, and I am
enabled to arrange for the expansion valve to have a short travel.
In the same way when the valves are working in the opposite direction to cut off
the steam I obtain a very sharp out off as the expansion valve C cuts off with its
outside edge say against the edge of the steam port a' in the usual way and at
the same time the internal rib 3 of the expansion valve C cuts off the steam at the
edge of the central steam passage a³.
I have described the operation of the valves as acting to admit and cut off steam
at the back of the piston but it will of course be evident that the valves operate in
the same way to admit and cut off steam at the front of the piston.
Having now particularly described and ascertained the nature of my said In-
vention, and in what manner the same is to be performed, I declare that what I
claim is:
1. In a steam engine cylinder, the employment of the main slide valve A made
with the additional steam inlet passage a between the ordinary steam passage ³ ³
in combination with the expansion valve C made with a cross rib c and two
chambers said valves being arranged for joint operation in the manner sub-
stantially as hereinbefore described with reference to the accompanying drawings.
2. A steam engine main slide valve of the kind herein referred to made with a
central steam inlet passage a between the two ordinary steam passages a¹ a³ said
central passage being adapted and arranged to receive steam from the top and
bottom of the slide valve to flow through the expansion valve to one or other of
the said two passages of the main slide valve, substantially as set forth.
Dated this 27th day of May 1897.
CHARLES BOSWORTH KETLEY,
Agent for the Applicant.