AN ATMOSPHERIC COUNTERBALANCE SLIDE VALVE FOR THE STEAM ENGINE, HYDRAULIC AND ALL OTHER MACHINES, IN WHICH THE SLIDE VALVE 13 USED OF REQUIRED
Year: 1853

page_text: LETTERS PATENT to Duncan Christie, of No. 1, Bromley Iligh
Street, in the Parish of Bromley, in the County of Middlesex,
Engineer, and John Cullen, of No. 1, Bromley High Street, in
the Parish of Bromley, in the County of Middlesex, Engineer, for
the Invention of "AN ATMOSPHERIC COUNTERBALANCE SLIDE VALVE
FOR THE STEAM ENGINE, HYDRAULIC AND ALL OTHER MACHINES, IN
WHICH THE SLIDE VALVE 13 USED OF REQUIRED."
Sealed the 9th June 1854, and dated the 9th December 1858.
PROVISIONAL SPECIFICATION left by the said Duncan Christie
and John Cullen at the Office of the Commissioners of Patents,
with their Petition, on the 9th December 1853.
We, DUNCAN CHRISTIE, of No. 1, Bromley High Street, in the
Parish of Bromley, in the County of Middlesex, Engineer, and Joun
CULLEN, of No. 1, Bromley High Street, in the Parish of Bromley, in
the County of Middlesex, Engineer, do hereby declare the nature of the
said Invention for "AN ATMOSPHERIC COUNTEL BALANCE SLIDE VALVE FOR
THE STEAM ENGINE, HYDRAULIC AND ALL OTHER MACHINES,
SLIDE VALVE IS USED OR REQUIRED," to be as follows:→
WHICH THE

page_text: An atmospheric counterbalance slide valve, where, by admitting the
atmospheric air on the face of the valve opposite to the steam ports,
the pressure of steam is taken off the valve; and this we accomplish
in the following manner:-
First, a vessel containing air being in contact with the face of the
valve.
Secondly, a spring or bar is placed on the air vessel for keeping it in
contact with the face of valve.
Thirdly, by using the spring or bar it is a preventative against
breaking of the valve, which often happens in sudden reversing of the
engine with the slide valve at present in use.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Duncan Christie and John Cullen in the Great
Seal Patent Office on the 9th June 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME,
DUNCAN CHRISTIE, of No. 1, Bromley High Street, in the Parish of
Bromley, in the County of Middlesex, Engineer, and JOHN CULLEN, of
No. 1, Bromley High Street, in the Parish of Bromley, in the County
of Middlesex, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Ninth day of December, in the year
of our Lord One thousand eight hundred and fifty-three, in the seven-
teenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said Duncan Christie and John Cullen,
Her special licence that they, the said Duncan Christie and John
Cullen, their executors, administrators, and assigns, or such others as
they, the said Duncan Christic and John Cullen, their 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 "AN ATMOSPHERIC

page_text: COUNTERBALANCE SLIDE VALVE FOR THE STEAM ENGINE, HYDRAULIC AND ALL
OTHER MACHINES, IN WHICH THE SLIDE VALVE IS USED OR REQUIRED," upon
the condition (amongst others) that they, the said Duncan Christie and
John Cullen, by an instrument in writing under their hands and seals,
should particularly describe and ascertain the nature of the said Inven-
tion, 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.
NOW KNOW YE, that we, the said Duncan Christic and John
Cullen, do hereby declare the nature of our said Invention, and in
what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
We call our Invention an atmospheric counterbalance slide valve,
for the use of the steam engine, hydraulic and all other machines, in
which the slide valve is used or required; and what we claim as our
Invention is the construction of the valve and the principle thereof,
the valve being a slide valve with two faces and two backs, whereby
steam or any other fluid have no effective pressure, they being let in at
any position between the two backs, the valve being within the chest
(A). We also claim as our Invention the construction of the cup (C),
and the principle thereof; it having an upward and downward motion,
and kept steam-tight by the packing (O), the cup being held to the
face of valve by the spring or bar (J), and the area of the cup exposed
to the atmosphere being as large as to counterbalance the effects on
the bottom face of the valve caused by its being open to the atmo-
sphere, and the cup (C), being open to the atmosphere through the
aperture (S), through which it is also lubricated, the cup (C), having a
small flange to prevent it passing through the cover (D), the flange
being at a distance from cover (D), so as to allow the valve to lift in
cases such as will occur in locomotives when the steam condenses
in the cylinder, the hole in the valve through which the spindle passes
being oblong to allow the valve to lift, the spring or bar (J) forcing the
cup (C), and the valve, to their proper places when the water has
escaped. The packing (N) is to prevent the steam from passing along

page_text: the face of cup (C). The space (Z), on the face of valve (B). is to
prevent any shoulder rising by the working of the valve. The Drawings
herewith being more fully described as follows:-(A) is a section of a
steam chest and equilibrium slide valve cut through the middle shewing
its parts B, represents the valve which has two faces and two backs;
C, is a cup or vessel moveable, admitting air by the aperture S, the
same aperture being also used for lubricating the valve B, there being
a space in the sides to hold packing N; M, is an iron ring forced on
the packing N by the screws L; D, is a lid or cover of steam chest,
having a hole through it large enough to admit the cup (C), also space
for packing (O), to prevent the steam from passing up the side of
cup (C); E, is a gland to force down the packing (O); F, is the
spindle whereby the valve is moved, and which is kept in position by
the nuts G, G; J, is a spring or bar bolted on the cover D, and acted
upon by the screw K, to hold the cup C, steam tight on the face of
valve B; B 1, represents the top face of valve B; B 2, represents
the bottom face of valve B; C 1, represents the face of cup C; C2
the back of cup C; B 3, shewing the valve B longitudinally; M 1,
shewing the face of ring M, which presses on the packing N; M 2, is
an edge view; J 1, is showing face of spring J; E 1, represents the
bottom side of gland E.
In witness whereof, we, the said Duncan Christie and John
Cullen, have heretofore set our hands and seals, this Ninth day
of June, in the year of our Lord One thousand eight hundred
and fifty-four.