Improvements in Three-way Valves.
Year: 1897

page_text: Date of Application, 13th Apr., 1897
Complete Specification Left, 5th Feb., 1898-Accepted, 5th Mar., 1898
Improvements in Three-way Valves.
I, THOMAS LEDWARD, of 35, Queen Victoria Street, London, in the County of
Middlesex, Engineer, do hereby declare the nature of this invention to be as
follows:
-
This invention relates to a combined three-way valve which at the same time
forms an automatic check and relief valve, to be used more particularly with
condensing steam engines, but may be used for many other purposes.
With steam engines it is often desirable (1st) to turn the exhaust steam to the
condenser or to the atmosphere at will, (2nd) to preyent the reflux of water
from the condenser into the engine; and (3rd) if by any accident the vacuum in
condenser is lost, to provide immediately and automatically a free escape for the
exhaust steam in another direction.
These three objects I attain in the following way. I will assume that the com-
bined valve which forms the subject of this invention stands vertically, though
this is not essential. The exhaust steam will then enter at the side and will have
above it a valve opening to the atmosphere and below it another valve (preferably
of piston form to enable it to be withdrawn from above) opening to condenser.
These two valves are fitted loosely to a central screwed spindle and may rise and
fall upon this spindle to an extent limited by stops upon the said spindle. If the
spindle is screwed upwards to its full extent the stops upon it raise the upper valve
to atmosphere, and close the one to condenser. If screwed downwards the opening
to atmosphere is closed and that to the condenser opened. This forms the three-
way valve.
If now the spindle is screwed upwards again to the extent of only half its full
traverse the stops upon it do not touch the valves therefore they remain as last
placed, namely, closed to atmosphere & open to condenser, but are free to slide
upon the spindle. If the vacuum in the condenser is lost the lower valve will be
pulled up sharply by the vacuum still in the exhaust pipe and so prevent the back
rush of water to the engine. At the same time the upper valve will be opened by
the pressure of exhaust steam as soon as it collects and will give a free exit to
atmosphere, without interfering with the running of the engine.
This forms the automatic check and relief valve.

page_text: Improvements in Three-way Valves.
I, THOMAS LEDWARD, of No. 35, Queen Victoria Street, London, in the County
of Middlesex, 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:
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This invention relates to a combined three way-valve which at the same time
forms an automatic check and relief valve; 'to be used more particularly with
condensing steam engines, but may be used for many other purposes.
With steam engines it is often desirable (1st) to turn the exhaust steam to the
condenser or to the atmosphere at will, (2nd) to prevent the reflux of water
from the condenser into the engine; and (3rd) if by any accident the vacuum in
condenser is lost to provide immediately and automatically a free escape for the
exhaust steam in another direction.
4
These three objects I attain in the following way. I will assume that the com-
bined valve which forms the subject of this invention stands vertically, though
this is not essential. The exhaust steam will then enter at the side and will have
above it a valve opening to the atmosphere and below it another valve (preferably
of piston form to enable it to be withdrawn from above) opening to condenser.
These two valves are fitted loosely to a central screwed spindle and may rise and
fall upon this spindle to an extent limited by stops upon the said spindle. If the
spindle is screwed upwards to its full extent the stops upon it raise the upper valve
to atmosphere, and close the one to condenser. If screwed downwards the opening
to atmosphere is closed, and that to the condenser opened. This forms the three-
way valve.
If now the spindle is screwed upwards again to the extent of only half its full
traverse the stops upon it do not touch the valves therefore they remain as last
placed, namely, closed to atmosphere and open to condenser, but are free to slide
upon the spindle. If the vacuum in the condenser is lost the lower valve will be
pulled up sharply by the vacuum still in the exhaust pipe and so prevent the back
rush of water to the engine. At the same time the upper valve will be opened by
the pressure of exhaust steam as soon as it collects and will give a free exit to
atmosphere, without interfering with the running of the engine. This forms the
automatic check and relief valve.
In order to explain my invention more clearly I append a drawing showing the
valve in section:-
a is the inlet branch for exhaust steam.
b is the outlet to atmosphere regulated by the valve disc e, which in the position
shown has been opened by the hand wheel 7 m.
c is the discharge branch to condenser controlled by the piston valve d, which
as shown in the drawing has been closed by the upward movement of the spindle h
on which its slides.
f is a stop upon the said spindle for raising the valve e.
g is a brass nut screwed to carry the central spindle h.
kis a gland.in the upper cover through which the spindle passes.
n is a pointer on the hand wheel which indicates by the positions, 1, 2, 3
whether the valve is set open to atmosphere, to automatic safety, or to condenser.
o is the outer casing or shell of the combined valve.
It should be noted that disc or "mushroom" valves, or piston valves, may be
used as desired for either or both of the valves d and e.
T

page_text: said
Having now particularly described and ascertained the nature of
my
invention and in what manner the same is to be performed, I declare that what I
claim is:-
1st. The combination of a three-way valve with an automatic relief valve as
herein described and illustrated in the annexed drawing.
2nd. For the purpose of an automatic relief and check valve the employment
of two mushroom or piston valves, or one mushroom and one piston valve sliding
upon a central spindle as herein described and illustrated in the accompanving
drawing.