Partially Balanced Slide Valve.
Year: 1896

page_text: Date of Application, 14th Sept., 1896 -
Complete Specification Left, 12th Jan., 1897-Accepted, 17th Apr., 1897
PROVISIONAL SPECIFICATION.
Partially Balanced Slide Valve.
I HARRY PERCIVAL ANDERSON Engineer 25 Wilmount Street Woolwich do
hereby declare the nature of this invention to be as follows:-
The herein mentioned partially balanced slide valve; is a square or rectangular
hollow inetal box; having two of its adjacent sides, sloping and paralell towards
each other; like the sides of a wedge; and sloping at the least possible angle found
practical so that there will be as little difference as possible, between the areas of
the top and the bottom of the valve.
To make my explanation more clear I will take numbers. Suppose, the valve to
measure 4" x 4" at the top and 6" in depth, and having a taper say of 1" in 6".
Then the bottom of the valve will measure 4" x 3". The difference of the area's
between the top and the bottom of the valve, will be 1 square inch.
The two sloping sides of the valve are smoothe plain surfaces: with a square or
rectangular hole or port, through the centre of both sides for the exhaust..
The valve chest or casing is an exact counterpart of the valve itsself. That is to
say a box having two of its sides paralell and sloping at the same angle as the sides
of the valve having the interior of the sloping sides smoothe plain surfaces, so that
when the valve is placed in its chest or casing, the two wedged shaped sides come
in contact with the corresponding sides of the casing and so forming two steam
tight working surfaces. The valve is supported intirely by its sloping sides and
free to slide backwards and forwards. Ou one side of the casing, the admission
ports are made; and on the other, there is a square or rectangular hole in the
center which answers for the exhaust to pass through so that when the exhaust
port in the valve is brought over one of the admission ports in the valve casing the
exhaust steam (or whatever is used) passes through the center of the valve and out
through the port in the casing.
The working of the valve is as follows.
The valve is placed in its casing. It bears intirely on its wedged shaped sides.
There is an open space between the bottom of the valve and the bottom of the
casing of about one inch; also a corrisponding space between the top of the valve
and the valve casing cover. (We will take steam for convenience.)
The steam passes freely above and below the valve. As no preasure can get
between the wedged shaped working surfaces of the valve and its casing all the
preasure that we have against the working surfaces, is the weight of metal + the
preasure per square inch on the difference between. the area's of the top and
the bottom of the valve which in this case is one square inch. Therefore if the
preasure that the valve is supposed to be working under is 60 lbs. to the square
inch-then 60 lbs. + the wt. of valve is all the preasure we have against the
working surfaces. The valve casing of course is longer than the valve, so as to
allow it the amount of travel necessary, like the ordinary slide valve. Provision is
also made, for connecting the valve to a spindle.
If found necessary a strip of metal resting on set. screws may be placed at the
bottom of the valve casing and running parallel with its sloping sides so that this
strip may be elevated, so as to toutch the bottom of the valve. This strip is to
prevent the valve from being forced down and jammed, by a sudden rush of steam
or whatever medium through which the preasure is applied.

page_text: This valve may be used for hydraulic, steam or any other fluid preasure engine.
Its object is to reduce friction on the working surfaces.
Dated this 11th day of September 1896.
Partially Balanced Slide Valve.
HARRY PERCIVAL ANDERSON 25 Wilmount Street Woolwich Mechanical
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 relates to a slide valve partially balanced, by allowing the fluid
pressure used to pass freely above and below the valve, in the same manner as
already discrived in my Provisional Spicification and illustrated by the drawings
accompanying this Complete Specification.
In all the views, the same letters are used for the same parts.
In the drawings herewith;
Figure 1 is a section through a cylinder to which the valve is applied.
Figure 2. is a section through M. N.
Figures 3 and 4 shows a modification of the valve as may be used for distributing
steam or other pressure; without exhaustion.
The slide valve is a square or rectangular hollow metal box, having two of its
opposite sides sloping towards each other and parallel, like the sides of a wedge,
and the said sides of the valve may incline towards each other at any angle
required.
Two opposite sides of the valve casing must also incline towards each other at
the same angle as the sides of the valve, so that when the valve is placed into its
casing the corresponding inclined sides of the said valve and casing are in perfect
contact and so form steamtight working surfaces.
There is a space between the top of the valve and casing, also a similar space
between the bottom of the valve and casing so that the pressure employed passes
freely above and below the valve and is at the same time excluded from the
working surfaces in contact. If required, a strip of metal (running parallel with
the sloping sides of the said valve and casing,) may be placed at the bottom of the
valve casing. This strip may rest on set screws or otherwise so that it may be
elevated or depressed so as to toutch the bottom of the valve and so prevent any
sudden shock from jamming the said valve.
The strip is shown in the 4 figures but is best seen in Figures 1 & 3.
In Figure 3, the valve (a) is shown in elevation only.
In Figures 1. & 2. the valve (a) is placed into its casing (6) resting on its opposite
parallel and sloping sides (c. c) which are plane surfaces, and the said sides of the
casing and the corresponding sides of the valve are in perfect contact. Steam (in
this instance) is admitted through the pipe (d) filling the casing, and the spaces
above and below the valve (e e) so that the top and the bottom of the valve, are
exposed to the pressure employed as the valve is moved backwards and forwards
by the spindle (f).
Steam is alternately distributed through the ports (g. g) to the cylinder, and
exhausted from the said cylinder through the port in the valve (h) and the pipe to
correspond (i).
It will be seen, that if so desired, steam may be admitted through the pipe (1) to
the enterior of the valve (h) to be distributed therefrom, the exhaust taking place
in the casing (b) and out through the pipe (d).

page_text: In Figures 3. & 4. steam is admitted through the pipe (d) into the casing (b)
from which it is distributed through, or shut off from the ports (g. g) by moving
the valve (a) one way or the other by the spindle (f) to which suitable
mechanism may be applied so as to be operated by the hand or otherwise as
desired.
In Figures 1 & 3 the bearing strip (k) is shown in section.
Having now particularly discribed and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is-
1. A slide valve, partially balanced by allowing such fluid pressure as used to
pass freely above and below the said valve, when admitted to the exterior of same,
to be distributed therefrom, and at the same time, to exclude such pressure as used
from the inclined working surfaces of the said valve and casing in contact,
substancially; as hereintofore discribed and shown in Figures 1 & 2.
2. A slide valve, partially balanced, by admitting such fluid pressure as used, to
the enterior of the valve, to be distributed therefrom, substancially as hereintofore
discribed and shown in Figures 1 & 2.
3. A partially balanced slide valve that may be used in combination with any
fluid pressure engine, or separately, to distribute alone, or to distribute and exhaust
any such fluid pressure desired, substancially.
Dated this 11th day of January 1897.
HARRY PERCIVAL ANDERSON,
Applicant.