IMPROVE- MENTS IN SLIDE VALVES
Year: 1860

page_text: LETTERS PATENT to James Bowyer D'Arcey Boulton, of Usk, in tho
County of Monmouth, Civil Engineer, for the Invention of "IMPROVE-
MENTS IN SLIDE VALVES."
Sealed the 24th April 1860, and dated the 7th January 1860.
PROVISIONAL SPECIFICATION left by the said James Bowyer D'Arcey
Boulton at the Office of the Commissioners of Patents, with his Petition,
on the 7th January 1860.
I, JAMES BOWYER D'ARCEY BOULTON, of Usk, in the County of Monmouth,
Civil Engineer, do hereby declare the nature of the said Invention for "IM-
PROVEMENTS IN SLIDE VALVES," to be as follows:-
My improvements in slide valves relate to those valves principally suited for
working in high-pressure steam or other fluids in which there is considerable
pressure bearing on the valve, and consist in so fitting & applying these valves,
that they shall always work in equilibrium or nearly so, and this without any
variation throughout their stroke or movement. By equilibrium I mean there
shall be little or no pressure on the valve face, the pressure of steam thereon
being counteracted by its pressure in an opposite direction. This has been
before attempted in various ways, but in all cases heretofore, there has been
considerable variation in the pressure on the valve face, according to the posi-
tion of the valve by partially enclosing the induction ports.

page_text: I form in the back of the slide case an opening, the area of which is about
equal to the area of the valve face, which opening is closed by a plate on the
back of the valve. This opening is furnished with packing suitably pressed up
by a gland to keep the contact with the plate steamtight. An arm projecting
from the plate above-mentioned serves as a connection whereby to actuate the
valve, which requires no other rod and stuffing box for that purpose. Thus far
the valve will be somewhat relieved of pressure on its face, but which would vary
according to its position. To perfect this, I extend the valve face considerably
in the direction of its length, and cut openings through it to suit the positions
of the induction ports; I lower the general level of the surface on the cylinder
around the face comprising the ports, which area is traversed by the extensions
of the valve face; in this sunk area of the surface at each end I raise a rib
circumscribing an area equal to, and of same form as the induction port.
These areas the extensions of the slide cover, but have steam admitted to them
at certain times in each stroke. When steam is therein contained, the pressure
on such areas above. & below is equal. At a certain point of the stroke, that is,
just when the valve is about to open an induction port, a small passage opens
from one of these circumscribed areas, and unites it with the waste port, thus
liberating the steam contained therein, and causing an increase. of pressure on
the back of the valve equal to the pressure removed at the moment of opening
the induction port. At the moment of covering an induction port, the steam
is again admitted to the circumscribed area to compensate for the increase of
pressure thereby added to the valve face.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Bowyer D'Arcey Boulton in the Great Seal Patent
Office on the 6th July 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
BOWYER D'ARCEY BOULTON, of Usk, in the County of Monmouth, Civil
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of January, in the year of our Lord Oue
thousand eight hundred and sixty, in the twenty-third year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said James
Bowyer D'Arcey Boulton, Her special licence that I, the said James Bowyer
D'Arcey Boulton, my executors, administrators, and assigns, or such others as
I, the said James Bowyer D'Arcey Boulton, my-executors, administrators,

page_text: 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 Inven-
tion for "IMPROVEMENTS IN SLIDE VALVES," upon the condition (amongst others)
that I, the said James Bowyer D'Arcey Boulton, my executors or adminis
trators, 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 Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
I
NOW KNOW YE, that I, the said James Bowyer D'Arcey Boulton, do
hereby declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement, reference being bad to the Sheet of Drawings hereunto
annexed, and to the letters and figures marked thereon (that is to say):
My improvements in slide valves relate to those valves principally suited for
working in high-pressure steam, or other fluids in which there is considerable
pressure bearing on the valve, and consist in fitting and applying these valves
that they shall always work in equilibrium, or nearly so, and this without any
variation throughout their stroke or movement. By equilibrium I mean, there
shall be little or no pressure on the valve face, the pressure of steam thereon
being counteracted by its pressure in an opposite direction. This has been
before attempted in various ways, but in all cases heretofore there has been
considerable variation in the pressure on the valve face according to the posi-
tion of the valve from its alternately closing and uncovering the induction ports.
I form in the back of the slide case an opening, the area of which is about
equal to the area of the valve face, which opening is closed by a plate on the
back of the valve. This opening is furnished with packing suitably pressed up
by a gland to keep the contact with the plate steam-tight; an arm projecting
from the plate above-mentioned serves as a connection, whereby to actuate the
valve which requires no other rod and stuffing box as usual for the purpose.
Thus far the valve will be somewhat relieved of pressure on its face; but which
would vary according to its position. To perfect this, I extend the valve con-
siderably in the direction of its length, and cut openings through it to suit the
positions of the induction ports. 1 lower the general level of the surface on
the cylinder around the face comprising the ports (the valve seat) which area
is traversed by the extensions of the valve face. In this sunk area of the
surface towards each end of valve seating, I raise a rib circumscribing an area

page_text: equal to and of same form as the induction port. These areas the exten-
sions of the slide valve cover, but have steam admitted to them at certain times
in each stroke the steam when therein contained; the pressure on such areas
is above and below, and therefore equal. At a certain point of the stroke, that
is, just when the valve is about to open an induction port, a small passage
opens from one of these circumscribed areas, and unites it with the waste port,
thus liberating the steam contained therein, and causing an increase of pressure
on the back of the valve equal to the pressure removed at the moment of
opening the induction port. At the moment of covering an induction port,
the steam is again admitted to the circumscribed area to compensate for the
increase of pressure to which the valve face would otherwise be subjected.
DESCRIPTION OF DRAWINGS.
Fig. 1 of the annexed Drawings represents a longitudinal section of a slide
valve complete constructed according to my Invention, with the valve in a
position closing the ports; Fig. 2 is a similar view of the valve A in position
with one port full open; while Fig. 3 represents a similar section to Fig. 2, but
with the valve A in position with the port only partially open; Fig. 4 represents
a plan of valve box; Fig. 5 a plan of the sent; and Fig. 6 a plan of the
interior of the valve box; Figs. 7, 8, and 9, being detached views of parts to
be herein-after referred to.
On back of valve A, a plate a, a, is formed, which closes an opening in the
valve box B, which is of such area that the pressure of steam pressing the plate
a, a, by reason of such opening (which plate a, a, covers) will be just equal to
the pressure to which the back of valve A, A, is subject when the ports are all
closed, the valve being then in equilibrium, as well understood. The opening
in the valve box is furnished with a packing gland C, separately represented
at Figs. 7 & 9, Fig. 7 being an isometrical view of the gland by which
the stuffing is packed & held; while Fig. 9 is an isometrical view of the inner
ring forming the stuffing box, the effect and object of which will be readily
understood. This ring may have an external flange to pass under the
entire stuffing to prevent it bearing on the plate a. The valve is actuated by
a bent arm D fixed to the plate, and carried to point d, in a direct line with
the line of resistance of the valve, at which point the connecting rod d' to work
the valve is attached.
In Fig. 8, which is an isometrical view of the valve A, with its back
plate a, a, it will be observed that the face or plate is extended lengthways
at m, m, in excess of what such valves usually are for ports situated as are the
induction ports e, e, of the steam cylinder E'; the port f being the eduction

page_text: as usual. The extensions m, m, of the valve face cover certain circumscribed
areas g, g, on the valve seat seen in Figs. 1, 2, 3, & 5; these areas are so
enclosed & acted on by the valve A, A, that they sometimes exposed to the
pressure of the steam, and at others open to the atmosphere or other eduction.
The other surface sunk below the face E, E, is freely exposed to the action of
the steam in the valve box, while the raised ribs or surfaces are level with the
face of the ports forming the face or bearing on which the valve slides. h, h',
are eduction passages by which the steam escapes from spaces 9, 9', the com-
munication being effected between g & h by passages i, i, formed in the thick-
ness of the plate m, and best seen in Fig. 2; 1, 1', are openings cut through
plate m, m, to pass the steam from valve box to the ports e, e¹, the valve A
acting in the opening and closing of those ports precisely as in ordinary valves,
which is also the case with the eduction of such valves. The action of the
improvements in this valve is as follow:-When the valve A moves to establish
communication between the port e & the eduction f, the opening I will admit
the steam under pressure to the area g, which becomes enclosed by plate m,
when the valve moves towards the opposite end of its course; at this time the
plate m will be subject on both sides to the pressure of the steam in the valve
box throughout the area 9; this continues till the valve commences to open the
induction of steam through port e, when simultaneously with such opening of
the induction through e, the little eduction passage i opens a passage for the
steam contained in space g, which escapes by h to the atmosphere or other
eduction. Thus the pressure removed from the back of the valve by the sudden
opening for the induction of steam through port e is immediately compensated
by the increase of pressure exerted by the steam in valve box on plate m, by
reason of the escape from area g, which is of the same area as port e; precisely
the same effect takes place in the other area g', to which steam is admitted
through e', when the eduction is established between e³ & f. The steain ad-
mitted and enclosed by the plate m, as before explained, is allowed to escape
at the moment the induction through e' is established, & while the valve is in
the position shown at Fig. 3, thereby establishing a pressure of steam on m to
compensate for its removal by the opening of e¹ to the valve box. Thus the
equilibrium of the valve is at all times maintained, which results in much less
wear & tear in the valve and its face, besides permitting of a smoother and more
equable motion & amount of power required to work the valve, the eduction
passages h, h, are simply placed in connection with the eduction passage f.
This valve, although described only with reference to steam, is also applicable
for regulating the transmission of other fluids under pressure.
Having described the nature of my Invention, & the manner of performing

page_text: the same, I declare that what I claim as my Invention to be protected by the
herein-before in part recited Letters Patent, is, the arrangement and com-
bination of parts herein-before described, by which the variable pressure on
slide valves is compensated, and their equilibrium established throughout their
movement, as herein-before described.
In witness whereof, I, the said James Bowyer D'Arcey Boulton, have
hereunto set my hand and seal, this Second day of July, in the year
of our Lord One thousand eight hundred & sixty.
JAS. BOWYER D'ARCEY BOULTON. (L.S.)