IMPROVEMENTS IN EQUILIBRIUM SLIDE VALVES FOR STEAM ENGINES AND ENGINES WORKED. BY COMPRESSED AIR, GAS, OB WATER
Year: 1874

page_text: LETTERS PATENT to Henry Willis, of the City of Worcester, Manu-
facturer, and James Blick, of the City of Worcester, Engineer, for
the Invention of "IMPROVEMENTS IN EQUILIBRIUM SLIDE VALVES FOR
STEAM ENGINES AND ENGINES WORKED. BY COMPRESSED AIR, GAS, OB
WATER."
Sealed the 8th June 1875, and dated the 23rd December 1874.
PROVISIONAL SPECIFICATION left by the said Henry Willis and
James Blick at the Office of the Commissioners of Patents, with
their Petition, on the 23rd December 1874.
WO, HENRY WILLIS, of the City of Worcester, Manufacturer, and
JAMES BLICK, of the City of Worcester, Engineer, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN EQUILIBRIUM SLIDE
VALVES FOR STEAM ENGINES AND ENGINES WORKED BY COMPRESSED AIR, Gas, or
WATER," to be as follows:-
Our Invention consists of the improvements in equilibrium slide
valves, herein-after described, by which improvements the balancing or

page_text: removal of the greater part of the pressure from the valve is effected
very simply and by means of arrangements of parts or additions, which
can be readily applied to the ordinary ports of steam cylinders.
We will describe our Invention as applied to a steam engine. We
dispenso with the ordinary steam chest, and in place thereof we fix at the
back of the slide of the valve a plate having two port holes of the size,
shape, and position of the two outer or induction ports of the valve seat
and slide. The said plate is parallel to the valve scat, and the slido
works steam tight between the said plate and the valve seat. Tho suid
plate and the seat of the valve aro connected both at top and bottom, 1
the connecting pieces forming with the said plate and valve seat a flat
rectangular channel, in which the slide works and fits steam tight. The
two ports in the fixed plate described are covered by a cap or the end of
the pipe by which the steam is delivered, which cap or end of the steam
pipe is secured to the said fixed plate. When the slide is in such a 1
position that the two induction ports are closed the steam presses only
on those portions of the slide covering the said ports, and when the slide
is in such a position that only one of the induction ports is covered the
steam presses only on that part of the slido covering the port.
By means of oil, fat, or other lubricant, applied in the manner herein- 2
after described, the working surfaces are kept steam tight and the slide
made to work smoothly. A transverse groove or depression is made across
the top edge of the slide, which groove opens into vertical grooves on the
front and back faces respectively of the slide. In the top of the channel
in which the slide works is a hole by which the lubricant is supplied to 2
the cross groove in the slide, and from it is distributed by the working
of the slide over the whole of the working surface of the slide.
The limited pressure on the slido referred to may be removed or
diminished by the use of an oscillating plate, which when the steam, is
entering one port closes the whole in the fixed plate opposite the other 3
port, and thus prevents more or less the pressure of the steam on the
portion of the slide covering the port.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Willis and James Blick in the Great Seal
Patent Office on the 17th June 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, HENRY
WILLIS, of the City of Worcester, Manufacturer, and JAMES BLICK, of
the City of Worcester, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of December, in the
year of our Lord One thousand eight hundred and seventy-four, in tho
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto us, the said Henry Willis and James Blick,
Her special license that we, the said Henry Willis and James Blick, our
exccutors, administrators, and assigns, or such others as we, the said
Henry Willis and James Blick, our 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, usc, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN EQUILIBRIUM SLIDE
VALVES FOR STEAM ENGINES AND ENGINES WORKED BY COMPRESSED AIR, GAS, OR
WATER," upon the condition (amongst others) that we, the said Henry
Willis and James Blick, our executors or administrators, by an instru-
ment in writing under our or their hands and seals, or under the hand
and seal of one of us or them, 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 we, the said Henry Willis and James Blick
do hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement thereof, that is to say :—
Our Invention consists of the improvements in equilibrium slido
valves, herein-after described, by which improvements the balancing or
removal of the greater part of the pressure from the valve is effected.
very simply and by means of arrangements of parts or additions which
can be readily applied to the ordinary ports of steam cylinders.
.

page_text: We will describe our Invention as applied to a steam engine. We
dispense with the ordinary steam chest, and in place thereof we fix at the
back of the slide of the valve a plate having two port holes of the size,
shape, and position of the two outer or induction ports of the valve seat.
The said plate is parallel to the valve seat, and the slide works steam
Light between the said plate and valve seat. The said plate and the scat
of the valve are connected both at top and bottom, the connecting pieces
forming with the said plate and valve seat a flat rectangular channel, in
which the slido works and fits steam tight. The two ports in the fixed
plate described are covered by a cap or the end of the pipe by which the
steam is delivered; which cap or end of the steam pipe is secured to the
said fixed plate. When the slide is in such a position that the two
induction ports are closed the steam presses only on those portions of the
slide covering the said ports, and when the slide is in such a position
that only one of the induction ports is covered the steam presses only
on that part of the slide covering the port.
By means of oil, fat, or other lubricant, applied in the manner herein-
after described, the working surfaces are kept steam tight and the slide
made to work smoothly. A transverse groove or depression is made
across the top edge of the slide, which groove opens into vertical grooves
on the front and back faces respectively of the slide. In the top of the
channel in which the slide works is a hole by which the lubricant is
supplied to the cross groove in the slide, and from it is distributed by
the working of the slide over the whole of the working surface of the
slide.
Having explained the nature of our Invention we will proceed to
describe, with reference to the accompanying Drawing, the manner in
which the same is to be performed.
Figure 1 represents in horizontal section the steam cylinder of a steam
engine to which an equilibrium slide valve constructed according to our
Invention is applied; Figure 2 is a side clovation of the same; and
Figure 3 is a cross section of the same taken on the line A, A,
Figure 2.
Figure 4 represents in front elevation, end elevation, edge view,
longitudinal vertical section, and cross section, the back plate of the case
or channel in which the slide works detached.
Figure 5 represents in clevation and longitudinal and cross sections

page_text: Figure 6 represents in side elevation, edge view, and end elevation,
and cross section, the slide of the valve detached, and Figure 7 represents
in clevations and section one of the glands or stuffing boxes of the slide.
Figures 4, 5, 6 and 7, are drawn double the scale of Figures 1, 2, and 3.
The same letters of reference indicate the same parts in the several
Figures of the Drawing.
a is the slide of the valve worked by an excentric driven from the
principal shaft of the engine in the usual way. The said slide a works
steam tight in a rectangular channel or case consisting of a back plate b
and valve scat c. The said back plate band seat c are connected
together by the longitudinal uprights c², c³, on the said valve seat to
which the back plate b is bolted (sec Figure 3), V ribs or feathers 6ª on
the said back plate b taking into V grooves c³ in the said uprights of the
valvo scat. In the back plate bare two steam ports d, e, and in the
valve seat c are three ports f, g, h, the two outer or induction ports ƒ, h,
opening into the passages i, k, passing to cach end of the steam cylinder
1, and the middle port g opening into the exhaust passage t. The said
steam ports d, e, in the back plate 6 have the size, shape, and position
of the outer ports f, h, of the valve seat c as represented in Figure 1.
In the slide a of the valve are two steam ports m, n, and an exhaust
port p. The slide a works through the stuffing boxes q, q, in the ends
of the rectangular chamber or case b, c. Over the steam ports d, e, in
the back plate is a cap or cover r, to the outer face of which the pipe &
delivering the steam is bolted as represented. By means of a stop-cock
u condensed water may be removed from the cap r.
The arrangement by which the working surfaces of the slide a arc.
lubricated and kept steam tight is best scen in Figure 6. In the top
edge of the slide a is a longitudinal groove which opens into the trans-
verse grooves w, w, made in the top edge and front and back faces.
respectively of the said slide. Oil, fat, or other lubricant is applied to
the longitudinal channel from the oil cup z provided with a stop-cock.
The passage from the oil cup & opens immediately opposite the longi-
tudinal channel v, and the oil delivered into the said channel v passes to
the transverse grooves or channels w, w.
By the reciprocating motion of the slide a the oil or lubricant is
delivered over the whole working surface of the said slide and the said

page_text: In Figure 1 the slido a is represented in the position in which tho
steam is just cut off from the steam cylinder 7, the steam ports d and e
in the back plate and the steam ports m, n, in the slide a being closed,
the exhaust port p in the said slide being by the same motion brought
opposite the port f and the passage i in the valve scat and cylinder,
and also opposite the exhaust port g and exhaust passage t, and the
exhaust from the cover end of the cylinder escapes to the said passage t.
The slido a is so arranged with respect to the excentric that it cuts off
steam to the cylinder when the steam piston is at about the middle of its
stroke, but the slide a may be so arranged that the cut-off is effected at
any required position of the piston's stroke.
When the slide a makes its return stroke in the direction of the
arrow y, Figure 1, the position of the ports is reversed, that is, tho
port m in the slide is brought opposite the ports & and f, and steam is
delivered by the passage i to the cover end of the steam cylinder /, tho
exhaust port p at the same time opening communication between the
opposite end of the cylinder and the exhaust passage (. When the
slide a makes its advance stroke in a direction contrary to that indicated
by the arrow y the steam port n is brought opposite the ports / and e
and steam is delivered through the port and passage k to the opposite
side of the piston, and so on. When steam is being delivered to either
end of the cylinder through the port mor n in the slide a the port d or e
in the back plate is covered by the slide, and steam in the steam cap »
presses only on that part of the slide covering the said port d or e; and
when the slido is in the position Figure 1 both the ports d, e, aro
closed, and steam presses on those parts of the slide covering the said
ports.
By our Invention the pressure of the steam on the slide a is limited to
such portions of its area as are equivalent to the areas of the ports a
and e, or of one of them, instead of pressing upon the whole area of tho
slide as in slide valves of the ordinary construction, and the valvo is
practically in a state of equilibrium as the resistance produced by tho
small residual pressure is by the lubrication of the valve reduced to an
almost insensible quantity.

page_text: Although we have described and represented our improved valvo as
applied to a steam engine yet it is equally applicable to engines worked
by compressed air, gas, or water.
Having now described the nature of our Invention and the manner
in which the same is to be performed, we wish it to be understood that
we do not limit ourselves to the precise details herein described and
illustrated as the same may be varied without departing from the naturo
of our Invention, but we claim as our Invention,-
The improvements in equilibrium slide valves for steam engines and
engines worked by compressed air, gas, or water, herein-before described
and illustrated in the accompanying Drawing, that is to say, the con-
struction of the slide a working steam-tight in a channel or case
composed of the back plate 6 and valve seat c, the said parts a, b, and c,
being provided with ports, and being combined together and working
substantially as and for the purposes described and illustrated.
Also the arrangement of parts for lubricating the slide of the valve,
as described and illustrated.
In witness whereof, wc, tho said Henry; Willis and James Blick,
have hereunto set our hands and scals, this Eleventh day of
June, in the year of our Lord One thousand eight hundred and
seventy-five.
Witness,
W. H. WaldrON,
High Street,
Worcester.
HENRY WILLIS.
(L.S.)
JAMES BLICK.
(L.S.)