IMPROVEMENTS IN BALANCED SLIDE VALVES
Year: 1897

page_text: PETER MACLEOD BAXTER, Copland Works, Govan, Glasgow, do hereby declare
the nature of this invention to be as follows:-
IMPROVEMENTS IN BALANCED SLIDE VALVES.
My invention relates to balanced slide valves having relief frames fitted on the
back of same to reduce the pressure, or friction, of the valve upon its seat, and also
includes the reduction of the length of the steam ports to the smallest amount
practicable. The valve is a "double" one, having two sets of relieving frames, one
at each end of valve; it can also be made with a single frame. The steam openings
to cylinder ports are directly; or nearly so; at the ends of the cylinders, thus
making the cylinder ports only the thickness of the cylinder metal in length. The
exhaust steam is carried directly through openings in the slide valve, and out at
the back. The openings in relieving frames may be made circular, rectangular or
any other convenient shape. The front face of the slide valve is in contact with the
cylinder valve face & the the relieving frames are in contact with the casing cover or
chest. The valve may be subdivided into two parts each contained in a separate
casing and connected by a spindle. The valve, or valves, may also be made double
faced, with relieving frames between, for acting in conjunction with two cylinders,
one of which supplies steam to the other. The live steam may also go through
the centre of the relieving frames & be discharged at the outer ends of valve or
valves, when necessary. A passage may be made directly between the two halves
of valve, when it is made double, so as to allow of a single steam or exhaust con-
nection as the case may be.
Dated this 3rd day of March 1807
P. MACLEOD BAXTER,
Copland Works, Govan.
Improvements in Balanced Slide Valves.
PETER MACLEOD BAXTER, Engineer, Copland Works, Govan, Glasgow, 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 improvement consists in the combination of two slide valves with relief frames
fitted on the back of each, one valve for each end of the cylinder and also in an
improved manner of packing frames so as to make them steam tight.

page_text: One face of each slide valve works against the cylinder face, the other against
the casing cover or sheet. The cavity of each valve is carried through from face
to face so that live steam may be brought to, or exhaust steam conveyed from the
cylinder through the valves to connections leading through the casing cover or
chest or the cavity of each valve may be connected by a port.
The relief frames are formed by inserting two solid rings, a working fit into the
recess at the back of each valve. These solid rings may have two split rings
bevelled inserted between them, with springs at the back of the inner solid ring.
These springs are arranged to force the solid rings against the casing cover or
chest, and to force the split rings open sideways and prevent the escape of steam
in that direction. Or the split bevel rings may be dispensed with, and asbestos
or other suitable packing inserted between the two solid rings and held out by
springs. The asbestos performing the function of the split rings and making the
arrangement tight sideways.
I may make the slide valve for each end of the cylinder separate castings, con-
nected by a spindle or I may combine the two in one casting. I do not confine myself
to the shape or number, of the relief frames. They may be circular or rectangular
and two or three sets may be fitted depending upon the form of the valve. The
frames may also be fitted to what are known as double or treble ported valves.
Two sets of valves substantially as described may be worked back to back in
conjunction with two cylinders, one set of valves being fitted with the relief frames
as above described, the other set of valves having plain faces against which the
relief frames fitted in the back of the other set of valves work.
In the accompanying drawings Figure 1 shows the longitudinal section of a
cylinder fitted with one form of the balanced slide valve; Figure 2 is a view look-
ing on back of above slide valve; Figure 3 is a sectional view of cylinder and slide
valve showing inlet and outlet passages: Figure 4 is a view looking on cylinder
face showing ports and passages. A & A¹ are the slide valves. B is the
face on which the fronts of the valves work and C the face on which the back of
valves work D & E are the solid rings, F & G the split beveled rings. H are the
springs behind the ring E and thus keep the rings D up to face C. Steam is
supplied through inlet I to the centres of valves A and A¹ and exhaust takes place
at ends of valves leaving the cylinder through outlet K. L and L¹ are the cylinder
ports giving a straight run to cylinder.
Steam can also be admitted at ends and exhaust from centre as in ordinary
slide valves.
On sheet No. 4 is shown various applications of the improvement arranged for
high pressure and for compound engines. Figure 5 for compound double cylinder
engines. Figure No. 6 for either compound or high pressure double
cylinder engines-having division plate between.--Figure 7 and Figure 7
for high pressure engines-and in
the case of both cylinders can
have four ports, i.e. the upper cylinder face can
ports same as the bottom one-and communication
can be either maintained or closed between the valves.
seperate valves and valve casings and double relief frames.
rectangular form of relief frames.
have two additional
for steam or exhaust
Figures 8 and 9 show
Figure 10 shows the
I do not confine myself to the arrangements as shewn on the different drawings.
The arrangements can be variously modified without departing from the essential
features of the invention.
Having now particularly described and ascertained the nature of my said
invention and in what manner the said is to be permormed I declare that what I
claim is:-
(1) Two slide valves fitted to a cylinder one for each end thereof each fitted with
relief frames, made to keep steam tight, substantially as described and shown in
Thi
9 2 0 0 and 10

page_text: (2) Two sets of slide valves working back to back and arranged for two cylinders
fitted with the relief frames and rings substantially as described and shown in
drawings Figures 5, 6, 7 and 7*.
D
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1 1
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1000