IMPROVEMENTS IN AND IN APPARATUS FOR UTILISING COMPRESSED AIR FOR OPERATING MACHINERY, AND IN PUMPING APPARATUS TO BE OPERATED THEREBY
Year: 1881

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for an Invention of "IMPROVEMENTS
IN AND IN APPARATUS FOR UTILISING COMPRESSED AIR FOR OPERATING
MACHINERY, AND IN PUMPING APPARATUS TO BE OPERATED THEREBY."
A communication from abroad by Charles William Cooper, of Brooklyn, in
the County of King's and State of New York, United States of America.
•
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 8th October 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN AND IN APPARATUS FOR
UTILISING COMPRESSED AIR FOR OPERATING MACHINERY, AND IN PUMPING
APPARATUS TO BE OPERATED THEREBY.' [A cominunication from abroad by
Charles William Cooper, of Brooklyn, in the County of King's and State of New
York, United States of America.]
This Invention relates, first, to a new arrangement of mechanism for using
compressed air in the transmission of power.
Heretoforo such mechanism was usually so arranged that the compressed air,
after it had done its duty, was exhausted and allowed to escape into the
atmosphere.
This Invention consists in confining the compressed air, after it has performed
its work, causing it to exhaust into a closed chamber, and holding the exhausted
air under a pressure greater than that of the atmosphere. But a difference of
pressure is maintained between the incoming and outgoing air sufficient for the
work that is to be done.
I will describe the principal Invention in connection with a certain new pumping
apparatus, but I desire it to be distinctly understood that the principal feature of
the Invention, namely, the employment of apparatus using compressed air so that
it will exhaust into closed chambers or pipes where it is held under reduced
D

page_text: pressure, is applicable to other machinery, and not limited to the particular
pumping apparatus described.
The Invention also consists in the detail arrangement of parts connected with
the pumping apparatus.
To carry the principal Invention into effect, a suitable steam engine operates the
plunger of an air compresser, and also the plunger of an auxiliary compresser if the
fatter is desired. Two reservoirs to contain air at high pressure communicato with
the main air compresser which is supplied with air from the one reservoir, and
discharges into the other reservoir. From both reservoirs pipes extend to the
places where the compressed air is to perform its work. Whatever the nature of
the work to be done, will cause corresponding difference in that part of the
apparatus to which these pipes extend. The compressed air may be used for
pumping purposes in connection with such apparatus as I shall hereafter describe,
or for driving a pump similar to an ordinary steam pump, or it may be used for
any other purpose, in which case the apparatus attached to the said pipes may be
correspondingly varied, but the main Invention which I wish bere to explain
consists in operating compressed air with the use of the said two pipes, in one of
which the air is under greater pressure than in the other.
In the operation of this apparatus, the reservoir into which the compresser
discharges is the supply reservoir, and the other the exhaust reservoir, and the
pipes leading from them are respectively the operating pipe and the exhaust pipe.
Now, as before stated, I hold the air after it has performed its work in compressed
condition in the exhaust reservoir and compress it still further by the compressor
into the supply reservoir, so that the same air is used over and over again and no
new air required, except to supply waste by leakage or the like.
There are several important advantages to be gained by this arrangement over
the old plan of exhausting into the open air, which advantages are principally the
following-First, the air to be compressed during the operation of the machine,
being already under high pressure, much less heat will be evolved in compressing
it to any greater additional degree, less heat taken up, and consequently less cold
produced in its expansion. Secondly, a much sinaller capacity of the compressing
engine running at a given speed will be required to compress air which is already
compressed still further than it would to take atmospheric air and compress it to
a certain definite point. Thirdly, in cases where it is inconvenient to work the
air expansively, much less power will be consumed in compressing the air to do a
given amount of work. Thus, for example, supposing compressed air to be used in
the ordinary way, if it is desired to work a direct acting pump which is placed in
a deep mine, and that a pressure of 100 pounds is required for the work, it follows
that, leaving out the question of increase of temperaturo, atmosphoric air at
15 pounds would have to be compressed to 115 pounds, and that the piston of the
compresser would work against an average pressure of 50 pounds. The volume of
air compressed would be 10 or 6%, the volume obtained for use in the engine.
Therefore the power used for the operation would be 6%, x 50=333_units, to
which would have to be added 100 units of power used in the engine, the result
being power expended 433, for power gained 100. In other words to gain 1 unit
of power, 4%, would have to be expended under the ordinary plan. In accordance
with this Invention, however, supposing the air should be already at a pressure
of 200 pounds in the exhaust chamber, to compress it to 300 pounds, or 100, higher,
as in the former case, the compresser would have to work against the same average
difference of pressure (50 lbs.), but the volume compressed would be only 100/200 or 1/
of the volume obtained for use in the engine. The operation would therefore
cost x 50 = 25, to which add the 100 used in the engine and the result will
be, power expended, 125, and power gained 100. Thus it will be seen that by
taking compressed air and further compressing it, the difference in volume alone
amounts, as compared with the duty of compressing ordinary air, to such a figure as
to demonstrate the great practical utility of the Invention.
Now, whether the operating and exhaust pipes lead into a cylinder so that the

page_text: air brought by the operating pipe will move the piston and then be exhausted into
the other pipe, or whether any other work is done by this compressed air, so long
as the pipes are connected with the apparatus to be operated in such a way that
the one pipe will be the supply pipe and the other pipe the exhaust pipe leading
back to the compresser and allowing the difference of pressure to operate the
machinery, this Invention will be employed. The degree of difference in pressure
contained in the two reservoirs may be varied according to the length of pipes
and the work to be done.
In the illustration or exemplification here described of a pump for raising
water from great depths by successive lifts, the supply and exhaust pipes lead to
a pump and to two chambers dividing the whole elevation into equal lifts, and
are alternately thrown into and out of communication therewith through the
medium of piston valves and branch pipes, there being a piston valve near each
of the chambers, and another near the pump proper. Each of these piston valves
consists of an outer shell connected with the supply and exhaust pipes, and with
a branch pipe that leads to the respective chamber. Within the shell is a plunger
rod having two separated pistons, which can be made to establish communication
between either the supply or the exhaust pipe and the chambers.
For this purpose of moving the valve plunger so as to establish alternate com-
munication with the supply and exhaust pipes, I prefer to employ a small force
pump, or a ram that is moved by the engine, and that cominunicates hydraulic
pressure to the several piston valves. When the hydraulic pressure moves the valve
plunger in one direction a spring is compressed which moves the valve plunger in
the opposite direction, when the hydraulic pressure is released so as to change the
communication with the supply and exhaust pipes.
The arrangement is such that whenever the piston valves are moved by the
hydraulic pressure or by the spring, the first chamber next above the pump
is thrown into communication with that one of the two pipes (supply and exhaust)
with which the second or next higher chamber and the pump aro out of communi-
cation, and vice versa.
Instead of employing a spring to reverse the piston valves, hydraulic pressure
may be applied at the opposite end of each valve shell to obtain the reciprocating
action of the valve plunger by first forcing the water against one end and then
against the other end of each of said plungers.
The pump is a vessel larger at the upper than at the lower part, and contains
two connected hollow plungers, which are of different sizes, the upper plunger
being the largest. The lower plunger has a hole in the bottom and a valve that
opens inwards, so that any water entering the pump from below through the
suction pipe may pass freely into and through both plungers. The lower plunger
is closely embraced by a packing ring secured in the upper end of the smaller part
of the pump chamber, and the upper plunger is packed by a ring attached to its
upper end or to the wall of the pump chamber. When these plungers are elevated
the upper packing ring is raised by its plunger, or if the ring is fastened to the
wall of the chamber the plunger slides through it, but the lower packing ring
remains to prevent communication between the upper and lower parts of the pump
chamber that surrounds the said plungers.
A branch of the high pressure or supply pipe enters an auxiliary chamber near
the pump, and from there a pipe extends into the space around the upper plunger
and between these two packing rings, so that in the said space the influence of
the high pressure air is always felt. Another pipe leads into the upper part of the
said chamber from the discharge pipe just above the pump, and is provided with a
check valve, which allows water to enter said chamber to make up for any leakage
that may occur, but not to return.
The pipe leads up from the pump chamber to the first chamber next above.
Another pipe leads from the first chamber to second chamber, and another pipo
leads away from the second chamber. Each of these pipes projects down-
wards into the respective chamber from which it leads, and each is provided with.

page_text: & varvo opening upwards. The suction pipe or the pump should have a foot
valve.
The branch pipes by which the chambers communicate with the supply and
exhaust pipes dip each into a small cup contained within the upper part of the
respective chamber and capable of sliding on guide rods, and which, when reached
by the water in the chamber, will float and close the lower end of the pipe. The
cup has small holes in the bottom, covered by flexible strips, acting as valves to
prevent water entering the cups from below, and to let out any water that may
get into them.
In the second or upper chamber the dischargo pipe dips into a cup that is large
and heavy enough to prevent it being drawn up by the outflowing water when
the said chamber contains a proper supply. But when the chamber is nearly
emptied, and while the discharge pipe still dips into water, the pressure of water
on top of the cup is reduced, and the cup will then float, rise, and close the lower
end of the discharge pipe to prevent the escape of compressed air.
The two chambers are so placed as to divide the whole elevation of water into
equal lifts, and each alternately receives water from the chamber next below it and
discharges it into the one next above, the uppermost one discharging it to its final
roceptacle.
I have only mentioned two chambers or vessels, but their number may be
increased or reduced if desired. The pressure of air on the pump and the two
chambers alternate, that is to say, when the high pressure enters the pump lower
pressure is in the chamber first above, and high pressure in the second chamber, and
afterwards the pressures are reversed simultaneously in all the chambers, and so on
continuously.
The operation of the apparatus is as follows:-When high pressure enters the
upper part of the pump chamber, the pump plunger will be forced down, and the
water contained in the pump chamber forced out through the discharge pipe into
the first chamber above, which at that time has low pressure on it, and this will
continue until the position of the plunger valves is reversed, or until the cup valve
closes the air pipe that leads into the vessel first above the pump. At the same
time the water is discharged under high pressure from the second vessel until tho
cup within it floats and closes the discharge pipe. All the piston valves are then
reversed, taking the high pressure away from the second chamber and from the
upper part of the pump chamber, and transferring it to the first chamber. But
high pressure still remains in the space which surrounds the upper plunger of the
pump, and is sufficient there to overbalance the lower pressure on the whole area
and on the upper plunger, and cause that plunger to lift into the pump chamber
and thereby to raise the lower plunger, draw up water through the suction pipe
into the lower part of the pump chamber, and thus replace the water in the pump
chamber that had previously been discharged. The pressure of atmospheric air
forces the water up through the suction pipe into the pump. At the same time
the water is discharged from the first vessel into the second vessel to fill the gap
made by the previous discharge from the second vessel. But the first vessel is
never empty to such an extent as to permit the air to escape through the discharge
pipe. The lower or suction plunger should have a capacity slightly in excess of
the discharge from the second chamber to insure the filling of the chambers with
water up to the air pipes, for, if thero should be a deficiency in the supply, it
would be cumulative, and finally lead to waste of air through the discharge
pipe.
Any deficiency of air caused by leakage in the supply and exhaust reservoirs is
supplied by the small auxiliary compressor, which receives atmospheric air by the
action of a weighted lever whenever any pressure in the supply reservoir gets below
the point for which the said regulator is set, and when the auxiliary compressor is
thus supplied with air, it forces the requisite supply into the supply reservoir.
The pumping apparatus can be worked with compressed air at any degree of
pressure, provided the proper difference of pressure in the reservoirs, according to

page_text: the height of water columns, is continually produced. The higher the pressures
at which the air is used, the greater the economy of power. After fixing upon the
pressures and calculating the quantity of water thereby discharged at each full
stroke of the pump, the volume of the higher compressed air to be forced into the
supply reservoir by each stroke of the compresser must be approximately calculated,
and the number of strokes of the ram or force pump, as compared with those of
the compresser, will then have to be adjusted accordingly by proper mechanism.
With a given difference of pressure, the higher both pressures are, the less pro-
portionate difference there will be between them, and consequently the greater
will be the volume of the higher compressed air furnished by cach stroke of the
compresser. This fact renders the furnishing of the proper quantity of air by the
compresser regular, for if there should be a deficiency of air from leakage or
otherwise, the pressure in the supply reservoir would fall below the point for
which the regulator is set, and cause the valve to open, admitting air to the
auxiliary compresser, which air will then be pumped into the supply reservoir.
On the other hand, should there be more air in the reservoirs than the necessary
quantity, so that a greater volume should be pumped than could be used by the
vessels discharging water, the effect would be an increase of pressure in the supply
reservoir, and a reduction of pressure in the exhaust reservoir, causing a greater
difference of pressure between them. This increase of difference would cause less
volume to be pumped into the supply reservoir, which would continue to decrease
until the volume so pumped should be exactly balanced by the amount used in the
discharge of the water. Care must however be taken not to make the difference
of pressure unnecessarily great, as this would throw unnecessary labor upon the
compressing apparatus.
The exhaust pipe may in many cases take the place of the exhaust reservoir,
which may be dispensed with. In fact both reservoirs are but enlargements of the
supply and exhaust pipes respectively.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alexander Melville Clark in the Great Soal Patent Office on
the 6th April 1882.
51
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. IMPROVEMENTS IN AND IN APPARATUS FOR UTILISING
COMPRESSED AIR FOR OPERATING MACHINERY, AND IN PUMPING APPARATUS TO
BE OPERATED THEREBY." A communication from abroad by Charles William
Cooper, of Brooklyn, in the County of Kings and State of New York, United
States of America.
This Invention relates, first, to a new arrangement of mechanism for using
compressed air in the transmission of power.
Heretofore such mechanism was usually so arranged that the compressed air
after it had done its duty was exhausted and allowed to escape into the
atmosphere.
This Invention consists in confining the compressed air, after it has performed
its work, causing it to exhaust into a closed chamber, and holding the exhausted
air under a pressure greater than that of the atmosphere. But a difference of
pressure is maintained between the incoming and outgoing air sufficient for the
work that is to be done.
I have in the accompanying Drawing illustrated the principal Invention in
connection with a certain pumping apparatus, which also forms part of the present
Invention, but I desire it to be distinctly understood that the principal feature of
the Invention, namely, the employinent of apparatus using compressed air, so that
it will exhaust into closed chambers or pipes, where it is held under reduced
pressure, is applicable to other machinery, and not limited to the particular pumping
apparatus on which it has been illustrated.
The Invention also consists in the detail arrangement of parts connected with
the pumping apparatus, all as hereinafter more fully described.
In the accompanying Drawings, Figure 1 is a side view partly in section of the
improved apparatus; Figures 2 and 3 are detail longitudinal central sections of
the piston valves for reversing the action of the pump; Figure 4 is a detail vertical
central section of the plunger and its containing chamber; Figuro 5 is a detail
vertical central section of one of the cup valves placed beneath the air pipes;
Figure 6 is a bottom view of said cup valve.
A represents a suitable steam engine which operates the plunger of an air
compressor B, and also the plunger of an auxiliary compresser C, if the latter is
desired; D and E are two reservoirs of proper strength arranged to contain air at high
pressure. Both these reservoirs communicate by pipes with the air compressor B,
the pipe a which extends from the reservoir E to the compressor B being the air
supply pipe for the compressor, and the pipe b, which extends from the compressor B
to the vessel D, being the air discharge pipe of said compressor. Both reservoirs D
and E also have pipes that extend to the places where the compressed air is to
perform its work, the pipe F extending from the reservoir D, and the pipe G from
the reservoir E. That part of the apparatus to which the pipes F and G extend
will be varied according to the nature of the work to be done. The compressed
air may be used for pumping purposes in connection with such apparatus as I shall
hereafter describe, or for driving à pump similar to an ordinary steam pump; or it
may be used for any other purpose, in which case the apparatus attached to the
pipes F and G may be correspondingly varied, but the main Invention which I wish
here to explain consists in operating compressed air with the use of the two pipes F
and G, in one of which (F) the air is under greater pressure than in the other.

page_text: In the operation of this apparatus the pipe F is the operating pipe and the
pipe G the exhaust pipe; the reservoir D the supply reservoir, and the reservoir Ę
the exhaust reservoir. Now as before stated, the air is held after it has performed
its work in compressed condition in the reservoir E, and compressed still further
by the apparatus B into the reservoir D, so that the same air is used over and
over again, and no new air required except to supply waste by leakage or the
like.
There are several important advantages to be gained by this arrangement over
the old plan of exhausting into the open air, which advantages are principally the
following: First, the air to be compressed by the apparatus B during the operation
of the machine, being already under a high pressure, much less heat will be evolved
in compressing it to any greater additional degree, less heat taken up, and con-
sequently less cold produced in its fexpansion; secondly, a much smaller capacity
of the compressing engine running at a given speed will be required to compress
air which is already compressed, still further than it would to take atmospheric air
and compress it to a certain definite point; thirdly, in cases where it is incon-
venient to work the air expansively much less power will be consumed in
compressing the air to do a given amount of work. Thus, for example, supposing
compressed air to be used in the ordinary way if it is desired to work a direct
acting pump which is placed in a deep mine, and that a pressure of 100 pounds is
required for the work, it follows that, leaving out the question of increase of
temperature, atmospheric air at 15 pounds would have to be compressed to
115 pounds, and that the piston of the compressor would work against an average
pressure of 50 pounds. The volume of air compressed would be 10 or 6%, the
volume obtained for use in the engine. Therefore the power used for the operation
would be 6%, x 50 = 333 units, to which would have to be added 100 units of
power used in the engine, the result being power expended 433 for power
gained 100. In other words, to gain 1 unit of power, 4%, would have to be
expended under the ordinary plan. In accordance with this Invention, however,
supposing the air should be already at a pressure of 200 pounds in the exhaust
chamber E, to compress it to 300 pounds or 100 higher, as in the former case, the
compressor would have to work against the same average difference of pressure
(50 lbs.), but the volume compressed would be only 188 or half of the volume
obtained for use in the engine. The operation would therefore cost 1/2 × 50 = 25,
to which add the 100 used in the engine, and the result will be, power expended
125, and power gained 100. Thus it will be seen that by taking compressed air
and further compressing it, the difference in volume alone amounts, as compared
with the duty of compressing ordinary air, to such a figure as to demonstrate the
great practical utility of the Invention.
Now whether the two pipes Fand G lead into a cylinder so that the air brought
by the pipe F will move the piston and then be exhausted into the pipe G, or
whether any other work is done by this compressed air, so long as the pipes F
and are connected with the apparatus to be operated in such a way that the
pipe F will be the supply pipe and the pipe G the exhaust pipe, leading back to
the compresser and allowing the difference of pressure to operate the machinery,
the Invention will be employed. The degree of difference in pressure contained in
the reservoirs D and E may be varied according to the length of pipes and the
work to be done.
In the illustration or exemplification here described of a pump for raising water
from great depths by successive lifts, the pipes F and G lead to the pump H and
to the chambers I and K, and are alternately thrown into and out of communi-
cation therewith through the medium of piston valves L and branch pipes U, there
being a piston valve L near the chamber K, another near the chamber I, and
another near the pump proper H. Each of these piston valves consists of an outer
shell d into which enters a branch of the pipe F and a branch of the pipe G, as
shown in Figure 2, and from which projects the pipo U that leads to the proper
chamber H, I, ar K. Within the shell D is contained a plunger rod e having two

page_text: separated pistons, which can be moved by proper apparatus so as to establish
communication between the pipes G and U, as in Figure 2, or between the pipes F
and U, as in Figure 3. For this purpose of moving the plunger e so as to throw
the pipe U into alternate communication with the supply and exhaust pipes F, G,
I prefer to employ a small plunger pump N of suitable construction, or a ram that 5
is moved by suitable connection with the engine A, and that communicates
hydraulic pressure through a pipe P to the valves e in the several shells d.
A spring (see Figure 2) tends to counteract the hydraulic pressure in the pipe P.
Whenever the piston of plunger pump N advances, it forces the water in the
pipe P against the plunger e and compresses the spring f, as indicated in Figure 2. 1
Whenever the piston in the plunger pump N recedes to take off the pressure from
the contents of the pipe P, the spring f reasserts its power and moves the plunger e
so as to change the communication of the pipe U with one of the pipes F or G. It
will be seen from Figure 1 that the piston valve L near the chamber K receives
the branch of the pipe Pat the same end as the piston valve near the pump H, but
that the piston L near the chamber I receives the pipe P at the opposite end. By
this arrangement whenever the plungers in the said piston valves are moved by
the hydraulic pressure or by the spring f, the chamber I is thrown into communi-
cation with the pipe F or G with which the pump and chamber K are out of
communication, and vice versa. Instead of employing the spring f, as shown in 2
Figure 2, I may lead another pipe from the plunger pump N into the opposite
end of each shell d, as shown in Figure 3, and indicated by dotted lines in
Figure 1. By this arrangement the reciprocating action of the plunger e would be
obtained by first forcing the water against one end, and then against the other end
of each of said plungers e.
2
The pump is a vessel larger at the upper than at the lower part, as shown
in Figure 1, and contains two connected hollow plungers T and V which are of
different sizes, the upper plunger T being the largest. The lower plunger V has
a hole in the bottom and a valve g that opens inwards, so that any water entering
the pump from below through the pipe M may pass freely into and through both
plungers V and T. The plunger V is closely embraced by ring h that is placed
and tightly secured in the upper end of the smaller part of the pump chamber H,
and the plunger T is packed by a ring i that is attached to its upper end, or to
the wall of the pump chamber H. When the plungers V, T, are elevated, as in
Figure 4, the packing ring i is raised by its plunger T; or if the ring is fastened to 3
the wall of the chamber, the plunger slides through it, but the packing ring h
remains to prevent communication between the upper and lower parts of the pump
chamber that surrounds the said plungers.
.
A branch of the high pressure pipe F enters a chamber X, and from there a
pipe extends into the space m that is contained between the rings h and i,
plunger T, and pump chamber H, so that in the said space m the influence of the
high pressure air is always felt. R is the pipe leading from the pump H to the
chamber I; R¹, the pipe leading from the chamber I to the chamber K; and R²
the pipe leading away from the chamber K. Each of these pipes is provided with
a valve n opening upwards. The pipe R projects downwards into the chamber H,
the pipe R into the chamber I, and the pipe R into the chamber K, as shown.
M is the suction pipe of the pump, and should be provided with a foot valve to
hold the water that enters it. Y is a pipe leading into the upper part of the
chamber X from the pipe R, and is to be provided with a check valve, which allows
water to enter into the chamber X, but not back. Wherever a pipe U enters one!
of the chambers above described it dips into a small cup S (see Figure 5), which is
capable of sliding on guide rods o, and which, when it is reached by the water,
will float and close, the lower end of the pipe U and prevent water from entering
such pipe. The cup S has small holes in the bottom covered by strips p of rubber
or equivalent material. These strips act as valves to prevent water entering the
cups from below, and to let out any water that may perchance get into them. A
similar cup S is applied if desired to the lower end of the pipe j. In the upper

page_text: chamber K the discharge pipe R³ dips into a cup W that is large and heavy
enough to prevent it being drawn up by the water when the chamber K contains
a proper supply; but when the chamber K is nearly emptied, and while the
pipe R still dips into water, the pressure of water on top of the cup W is
reduced, and the cup W will then float on the remaining water, rise to the pipe R',
and close the lower end thereof to prevent the escape of compressed air through
the pipe Rº. The chambers K and I are so placed as to divide the whole elevation
of water into equal lifts, and each alternately receives water from the vessel next
below it, and discharges it into the one next above, the last vessel K discharging
it to its final receptacle. There are only two vessels I and K shown in the
Drawing, but their number may be increased or reduced if desired. The pressure
of air on the vessels H, I, and K alternate, that is to say, when the high pressure
enters the vessel H through the pipe U lower pressure is in the vessel I and high
pressure in the vessel K, and afterwards the pressures are reversed simultaneously
in all the chambers, and so on continuously.
The operation of the apparatus is as follows:-When high pressure from the
pipe F enters the upper part of the chamber H the plunger T will be forced down,
and the water contained in the vessel H forced out through the pipe R into the
vessel I, which at that time has low pressure in it, and this will continue until the
ram N reverses the position of the plunger valves c, or until the cup valve S closes
the air pipe U that leads into the vessel I. At the same time the water is dis-
charged under high pressure from the vessel K until the cup W closes the pipe R³.
The action of the ram or pump N then reverses all the piston valves L; taking the
high pressure away from the vessel K and from the upper part of the vessel H and
transferring it to the vessel I; but high pressure still remains in the space m
which surrounds the plunger T, and is sufficient there to overbalance the lower
pressure on the whole area and on the plunger T, and cause that plunger to lift
into the vessel B, as shown in Figure 4, and thereby to raise the plunger V, suck
water through the pipe M into the lower part of the chamber H, and thus replace
the water in the chamber H that had previously been discharged. The pressure of
atmospheric air forces the water up through the suction pipe M into the pump.
At the same time the water is discharged from the vessel I through the pipe R¹
into the vessel K to fill the gap made by the previous discharge from the vessel K;
but the vessel I is never empty to such an extent as to permit the air to escape
through the pipe R'. The suction plunger V should have a capacity slightly in.
excess of the discharge from the chamber K to ensure the filling of the vessels with
water up to the air pipes, for if there should be a deficiency in the supply it would
be cumulative, and finally lead to waste of air through the discharge pipe. The
vessel X is for the purpose of holding a supply of water around the plunger T,
although on principle it would be as well to lead the air direct from the pipe F,
through the pipes j, L, into the space m, but by having water under high pressure
in the said space m the tendency of the air under pressure to leak around the
rings i and h is overcome. As the high pressure is constant in the space m, while
it is intermittent on the other side of the ring i, the balance of leakage, if any,
would be from the outside of the plunger into the interior of the chamber H.
Water passing through the check valve of the pipe Y, when the water column of
the pipe R has the higher pressure to assist it, will flow into the chamber X, and
make up for any leakage that may take place through the rings h and i.
Any deficiency of air caused by leakage in the reservoirs D and E is supplied by
the small compressor C, which receives atmospheric air through the pipe r which
opens under the influence of a weighted lever a whenever any pressure in the
reservoir D gets below the point for which the regulator 8 is set, and when the
compresser C is thus supplied with air it forces the requisite supply into the
reservoir D by the pipe t.
The pumping apparatus can be worked with compressed air at any degree of
pressure, provided the proper difference of pressure in the reservoirs according to
the height of water columns is continually produced. The higher the pressures' at

page_text: 8
which the air is used, the greater the economy of power. After fixing upon the
pressures and calculating the quantity of water thereby discharged at each full stroke
of the pump, the volume of the higher compressed air to be forced into the vessel D
by each stroke of the compresser must be approximately calculated, and the
number of strokes of the ram or small pump N as compared with those of the
compresser will then have to be adjusted accordingly by proper mechanism. With
a given difference of pressure, the higher both pressures are the less proportionate
difference there will be between them, and consequently the greater will be the
volume of the higher compressed air furnished by each stroke of the compresser.
This fact renders the furnishing of the proper quantity of air by the compresser
regular, for if there should be a deficiency of air from leakage or otherwise the
pressure in the chamber D would fall below the point for which the regulator a is
set and cause the valve and the pipe r to open, admitting air to the compresser C,
which air will then be pumped into the reservoir. On the other hand, should
there be more air in the reservoirs than the necessary quantity, so that a greater
volume should be pumped tlian could be used by the vessels discharging water, the
effect would bo an increase of pressure in the chamber D and a reduction of
pressure in the chamber E, causing a greater difference of pressure between
them. This increase of difference would cause less volume to be pumped into the
chamber D, which would continue to decrease until the volume so pumped should
be exactly balanced by the amount used in the discharge of the water. Care must
however be taken not to make the difference of pressure unnecessarily great, as
this would throw unnecessary labor. upon the compressing apparatus. The pipe G
may in many cases take the place of the reservoir E, which may be dispensed
with. In fact, both reservoirs D, E, are but enlargements of the pipes F and G
respectively.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
hereinbefore in part recited Letters Patent is,―
1st. The method herein described of utilising compressed air in operating
machinery, which method consists in conveying the compressed air from a compressor
to the place where it is to be utilised, and in then exhausting it, first into a closed
chamber or pipe, and then back into the compresser under pressure greater than
that of the atmosphere, but less than that created by the compresser, so as to
utilise the difference of pressure for operating the machinery, substantially as
herein shown and described.
2nd. In apparatus for utilising compressed air, the combination of the compresser B
with the pipes F and G, both of which communicate with the machinery to be.
actuated and with said compresser, all arranged for operation so that the same air
will be used over and over again, and maintained in the pipe F at a greater
pressure than in the pipe G, and in both pipes at a greater pressure than atmos-
pheric air, substantially as herein shown and described.
3rd. The combination of the compressed air chamber D, pipe F, and piston
valves L, with the pump H, chambers I, K, pipes M, R, R', R³, exhaust pipe Ġ, and
reservoir E, and with mechanism, substantially as described for moving the piston
valves, substantially as specified.
4th. The pump H combined with the smaller plunger V and larger plunger T,
and with the packing rings h and i, and with mechanism for maintaining constant
high pressure around the plunger T and alternating pressure within the said
plunger T, substantially as described.
5th. The sliding cup valve S having perforated bottom and flexible strips p
thereon in combination with the supply pipe U, substantially as described.
.
6th. In compressed air apparatus having supply reservoir D and exhaust
reservoir E, both arranged to hold the air under pressure, the combination of said
chambers D and E with the main compresser B and with the auxiliary compresser C,
pipe, regulator 8, and pipe t, substantially as described.
7th. The piston valve L combined with the pipes F, G, and U, and with the

page_text: plunger e, all arranged so that by moving said plunger the pipe U can be brought
into communication with the pipes F and G alternately, substantially as described.
8th. The combination of the compressed air pipe F with the pipe j, water
vessel X, and pipe 7, and with the pump chamber H and plunger T, all arranged
for operation substantially as specified.
9th. In the chamber K the combination of the compressed air supply pipe U
with the water discharge pipe R2 and cup W, all arranged to prevent the air from
escaping through the pipe R², as described.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my band and seal, this Sixth day of April, A.D. 1882.
A 15 LADY