Year: 1887

page_text: JOHN SANDERS STEVENS and CHARLES GEORGE MAJOR, Engineers of Janus
Works, Queen's Road Battersea in the County of Surrey do hereby declare the nature
of this invention to be as follows:-
Our Invention is a developement of our previous invention, described in Letters
Patent No. 9069 of the year 1886 granted to us, and particularly of that part which
relates to air expulsion apparatus. In that invention we assumed that in all cases
there would be a certain portion of the weight of the empty cage left unbalanced, for
the purpose of bringing the cage to the bottom when the water in the driving
cylinder was allowed to escape to the drains. Under such conditions, the suspended
cage would always exert a certain amount of pressure upon the water in the cylinder,
and this to a sufficient extent to effectually expel any air upwards through the air
expulsion trap described.
But we have found in practice, that in some cases greater economy may be secured
by completely balancing the weight of the empty cage, or even by slightly over-
balancing it. The cage can then be made to descend by producing a vacuum, partial
or complete, in the exhaust pipe. Any air in the cylinder, or in the pipe connecting
the cylinder with the controlling valve, would interfere with the requisite vacuum, &
prevent descent. The empty cage, being fully counterbalanced, would then exert no
pressure on the mixture of water and air in the cylinder, and no force would be
available for the expulsion of the air.
It is the object of our present invention to provide against this difficulty, and we
do so by constructing an air expulsion trap, which also acts as an automatic water
charging apparatus. We provide at some point above the highest water level of the
cylinder, a closed vessel having three separate pipe inlets or exits. The first pipe runs
from the bottom of the closed vessel, hereinafter called the "trap," to the top of the
cylinder, or the connecting pipe from controlling valve, in such a manner that all air
may rise freely from the cylinder and connecting pipe into the trap, or any water pass
downwards from the trap to the cylinder. The second pipe admits water, from any
convenient source, into the trap. The third pipe, is for the exit of air, and is
connected to one side of the trap as near the top as possible.

page_text: A float, preferably of wood, is provided within the trap, and has connected with it
suitable valves, or stoppers. for controlling the three pipe connexions described. That
for the first pipe at the bottom of the trap, is merely a taper stopper attached to the
lower side of the float, and which enters the pipe, nearly but not absolutely closing it
when the float descends, and is drawn out leaving a comparatively free passage when
the float rises. The valve for the second or feed pipe, is arranged to shut absolutely
tight in a direction towards the trap, by the pressure of the feed water behind it; it
is forced open against this pressure by the action of the falling float, and is allowed
to reclose when the float rises. The valve for the third or air exit pipe, is also made
to close absolutely tight, but in an outward direction, and is held in position by the
buoyancy of the float, assisted by any pressure which may exist within the trap; it is
opened against such pressure by the weight of the falling float.
The action of the apparatus is as follows:-
Assume that the lift cylinder has not been charged with water, and that it, together
with the connecting pipe to controlling valve, is filled with air. The trap will also
be filled with air, the float being at the bottom, the first pipe from the trap practically
closed by its stopper, and the valves of feed pipe and air exit pipe both held wide
open by the lowered float. Now if water is turned on to the trap through its second
or feed pipe, the displaced air will escape through the third pipe, and the float will
gradually rise, as it does so, withdrawing the stopper from the first pipe, allowing the
water to pass down into the cylinder, and the displaced air to escape upwards into the
trap and thence by the exit pipe into the atmosphere. The float will continue to rise,
opening the discharge stopper and closing the feed valve, till the flow through each is
equalised; it will then stand in that position till the cylinder is full of water, after
which the rising level of the water in the trap carrying up the float, will allow the feed
valve to close by the feed pressure; the air exit valve should still be partially open,
though if the feed valve should allow any more water to leak past it, the float would
rise still farther, and close the air exit valve; and this would not interfere with the
proper working of the apparatus.
The Lift is now charged with water and ready for use, and the controlling valve
may be opened to admit pressure to lift the cage. Should any air be admitted with
the water, it will find its way upwards, and into the trap; but having no power of
supporting the float, the latter will descend opening the air and feed valves, thereby
allowing the air to be blown out, and feed water to enter through the trap, till all air
is expelled, or caught in the upper portion of the trap.
If now the controlling valve be reversed for the empty cage to descend, and
the cylinder be put in communication with the exhaust, the water in the
connecting pipe from controlling valve to cylinder will tend to fall away, creating
a vacuum more or less perfect at the head of the cylinder. To make this
clearer, it should be remembered that the cylinder together with the connecting
pipe to valve form a syphon, of which the pipe is the longer leg, the
controlling valve being placed at the foot of the longer leg, and the air trap mounted
on the head of the syphon, and feeding into it. Opening the controlling valve to
exhaust, will then obviously produce a vacuum at the head of the syphon, and the
water from the trap will at once rush into it, bringing down the float, virtually closing
the communication between trap & syphon by the insertion of the stopper, and
simultaneously opening the feed valve which will supply water faster than will be
required to make good the slight leakage past the nearly closed stopper, thereby
keeping the vacuum sealed, till the controlling valve is again closed, and the float rises
to its normal position.
We partially close the bottom exit pipe from the trap by an imperfect stopper, in
preference to a water tight valve, for this reason. As soon as the lift begins to
descend, the float drops and the stopper closes. The air valve at the top of trap is
open, and if the stopper were a perfect valve it would be held down by the difference
between atmospheric pressure above it, and the vacuum beneath it. But during the
descent of the cage, the movement of the ram, which is entering the cylinder, may
lead to the introduction of a small quantity of air, sufficient to impair the vacuum so

page_text: far as to prevent the farther descent of the cage, and yet not to such a degree as to
release the valve at the foot of the trap, which would be still held down anchoring
the float to the bottom, even though the latter were completely immersed in water.
This defective action is avoided by allowing a small leakage of water past an im-
perfect valve. It could also be avoided by making the float more powerful
relatively to the stopper, but this course would often lead to inconvenient increase in
bulk.
The foregoing is a description of our invention in its simplest form, but we some-
times modify the details; as for instance ;--each or either of the three individual
valves of the trap may be replaced by two or more ;-the second or feed valve may be
made to close by the buoyancy of the float, and against the feed pressure ;—the air
valve may be made to close simultaneously with, instead of later than, the feed
valve-the bottom valve, or stopper, may be acted upon more powerfully by lever
action, instead of being attached directly to the float;-the imperfect valve or stopper
may be replaced by a perfect valve, combined with more powerful float action;-
toggle links, cams, levers, or other mechanism, may be introduced to give the float
more power over either or all of the valves.
·ו...
1 1

page_text: COMPLETE SPECIFICATION.
Improvements in and Connected with Hydraulic Lifts.
JOHN SANDERS STEVENS and CHARLES GEORGE MAJOR, Engineers of Janus
Works, Queen's Road Battersea in the County of Surrey, 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 :—
Our Invention is a developement of our previous invention, described in Letters
Patent No. 9069 of the year 1886 granted to us, and particularly of that part which
relates to air expulsion apparatus. In that invention we assumed that in all cases
there would be a certain portion of the weight of the empty cage left unbalanced,
for the purpose of bringing the cage to the bottom when the water in the driving
cylinder was allowed to escape to the drains. Under such conditions, the suspended
cage would always exert a certain amount of pressure upon the water in the cylinder,
and this to a sufficient extent to effectually expel any air upwards through the air
expulsion trap described.
But we have found in practice, that in some cases greater economy may be secured by
completely balancing the weight of the empty cage, or even by slightly overbalancing
it. The cage can then be made to descend by producing a vacuum, partial or complete,
in the exhaust pipe. Any air in the cylinder, or in the pipe connecting the cylinder
with the controlling valve, would interfere with the requisite vacuum, and prevent
descent. The empty cage, being fully counterbalanced, would then exert no pressure on
the mixture of water and air in the cylinder, and no force would be available for the
expulsion of the air.
It is the object of our present invention to provide against this difficulty, and we do
so by constructing an air expulsion trap, which also acts as an automatic water
charging apparatus. We provide at some point above the highest water level of the
cylinder A Fig. 1., a closed vessel B having three separate pipe inlets or exits C, D & E.
The first pipe C runs from the bottom of the closed vessel B, hereinafter called the
"trap" to the top of the cylinder A, or the connecting pipe F from controlling valve,
in such a manner that all air may rise freely from the cylinder A, and connecting
pipe F into the trap B or any water pass downwards from the trap to the cylinder.
The second pipe D admits water, from any convenient source, into the trap B.
The third pipe E, is for the exit of air, and is connected to one side of the trap as
near the top as possible. A float G Fig. 2 constructed of any suitable material
as for instance wood, a hollow metal case, or a skeleton frame filled with
cork, is provided within the trap B, and has connected with it suitable valves
or stoppers H, I, & J, for controlling the three pipe connexions described.
That for the first pipe at the bottom of the trap H, is merely a taper stopper
attached to the lower side of the float G, and which enters the pipe C, nearly but
not absolutely closing it when the float G descends, and is drawn out leaving_a
comparatively free passage when the float rises. The valve I for the second or feed pipe D,
is arranged to shut absolutely tight in a direction toward the trap, by the pressure of

page_text: the feed water behind it; it is forced open against this pressure by the action of the
falling float, and is allowed to reclose when the float rises. The valve J for the third
or air exit pipe E, is also made to close absolutely tight, but in an outward direction,
and is held in position by the buoyancy of the float &, assisted by any pressure which
may exist within the trap; it is opened against such pressure by the weight of the
falling float. Motion is communicated from the float G to the valves I & by means
of the links K and the three-armed lever L.
The action of the apparatus is as follows-
Assume that the Lift cylinder A has not been charged with water, and that it,
together with the connecting pipe F to controlling valve, is filled with air. The
trap B will also be filled with air, the float G being at the bottom, the first pipe C
from the trap practically closed by its stopper H, and the valves of feed pipe D, and
air exit pipe E, both held wide open by the lowered float and lever L. Now if water
is turned on to the trap B, through its second or feed pipe D, the displaced air will
escape through the third pipe E, and the float G will gradually rise, as it does so,
withdrawing the stopper H from the first pipe C, allowing the water to pass down
into the cylinder A, and the displaced air to escape upwards into the trap B and
thence by the exit pipe E into the atmosphere. The float G will continue to rise,
opening the discharge stopper H and closing the feed valve I, till the flow through
each is equalised; it will then stand in that position till the cylinder A is full of
water, after which the rising level of the water in the trap B, carrying up the float G,
will allow the feed valve I to be closed by the feed pressure; the air exit valve J
should still be partially open, though if the feed valve I should allow any more water
to leak past it, the float would rise still farther, and close the air exit valve J ; and
this would not interfere with the proper working of the apparatus.
The lift is now charged with water and ready for use, and the controlling valve
may be opened to admit pressure to lift the cage. Should any air be admitted into
the cylinder A with the water, it will find its way upwards, and into the trap B; but
having no power of supporting the float, the latter will descend, opening the air and
feed valves J and I, thereby allowing the air to be blown out, and feed water to enter
through the trap B, till all air is expelled, or caught in the upper portion of the trap.
If now the controlling valve be reversed for the empty cage to descend, and the
cylinder A be put in communication with the exhaust, the water in the connecting
pipe F from controlling valve to cylinder will tend to fall away, creating a vacuum
more or less perfect at the head of the cylinder A. To make this clearer,
it should be remembered that the cylinder A together with the connecting
pipe to valve form a syphon, of which the pipe F is the longer leg, the
controlling valve being placed at the foot of the longer leg, and the air
trap B mounted on the head of the syphon, and feeding into it. Opening
the controlling valve to exhaust, will then obviously produce a vacuum at the
head of the syphon, and the water from the trap B will at once rush into it,
bringing down the float G, virtually closing the communication between trap and
syphon by the insertion of the stopper H, and simultaneously opening the feed valve I.
which will supply water faster than will be required to make good the slight leakage
past the nearly closed stopper H, thereby keeping the vacuum sealed, till the con-
trolling valve is again closed, and the float G rises to its normal position.
As
We partially close the bottom exit pipe C from the trap B by an imperfect
stopper H, in preference to a water tight or perfect valve, for this reason.
soon as the lift begins to descend, the float drops and the stopper closes. The
air valve J at the top of trap is open, and if the stopper H were a perfect valve
it would be held down by the difference between atmospheric pressure above it,
and the vacuum beneath it. But during the descent of the cage, the movement of the
ram, which is entering the cylinder, may lead to the introduction of a small
quantity of air in the form of minute globules adhering to the surface of the
ram and carried past the packing, sufficient to impair the vacuum so far as to
prevent the farther descent of the cage, and yet not to such a degree as to release

page_text: the valve H at the foot of the trap, which would be still held down, anchoring
the float G to the bottom, even though the latter were completely immersed in water.
This defective action is avoided by allowing a small leakage of water past an
imperfect valve. It could also be avoided by making the float G more powerful
relatively to the stopper H, but this course would often lead to inconvenient
increase in bulk.
The foregoing is a description of our invention in its simplest form, but we
sometimes modify the details; as for instance; each or either of the three
individual valves of the trap may be replaced by two or more; the second or
feed valve I may be made to close by the buoyancy of the float, and against
the feed pressure-the air valve J may be made to close simultaneously with,
instead of later than, the feed valve I;-the bottom valve, or stopper H, may be
acted on more powerfully by lever action, instead of being attached directly to the
float; the imperfect valve or stopper may be replaced by a perfect valve,
combined with more powerful float action;-toggle links, cams, levers, or other
mechanism, may be introduced to give the float more power over either or all
of the valves.
Having now particularly described and ascertained the nature of our said invention,
and in what manner the same is to be performed, we declare that what we claim is ;
(1). A combined air expulsion and water charging trap, consisting of a case, a
float, water feed, air exit & bottom discharge valves or stoppers, and suitable
mechanism for actuating same as described.
(2). The combination of such an air expulsion and water charging apparatus, with
any hydraulic lift.
Dated this 10th day of August 1888