Year: 1885

page_text: I, HENRY EDWARD NEWTON of the Office for Patents, 6 Bream's Buildings,
Chancery Lane in the County of Middlesex Civil 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 combined water pump and air compressor, which is
especially designed for use in connection with hydraulic elevators and other
similar apparatus.
In operating this class of apparatus, it is common to have the water supplied
either from a considerable height, so that its fall is sufficient to produce the
necessary pressure, or from a tank or reservoir in which it is maintained under the
constant pressure of a volume of compressed air.-In this latter case, the air which
is confined in the tank or reservoir above the water, is constantly absorbed and
carried off by the water, so that in order to maintain the proper pressure upon the
water, it is necessary to have the supply of air in the tank constantly replenished.
This has heretofore been accomplished in a variety of ways. In some cases a
special air compressing pump has been provided for the purpose. In other cases,
the necessary air has been supplied by means of an air compressing pump, which
was operated from a cross head upon the piston rod of the water pump in the same
manner as the air pump of an ordinary condenser. In still other cases, the pump
by which the water was supplied to the tank has been arranged to force water into
the tank upon one stroke, and air upon the next, or to receive water for a part of
its stroke, and air for the remainder, so as to force a volume of mixed air and
water into the tank. All of these arrangements have, however, proved more or
less objectionable in practice; the first, because of the additional machinery, and
consequently extra expense involved; the second, because of the extra labor
thrown on the pump just at the end of its stroke; and the third, because it caused
the pump to operate in an irregular and spasmodic manner.
It is the object of the present invention to overcome these objectionable features,
and to provide a combined water pump and air compressor by which the water can

page_text: be supplied to the tank, and at the same time a sufficient amount of air introduced
to maintain the proper pressure upon the water, without putting extra labor upon
the pump at the end of the stroke, or giving to it a spasmodic or irregular action.
As a full understanding of the invention can be best imparted by a detailed
description of the apparatus in which it is embodied, such description will now be
given, reference being had to the accompanying drawings, in which :
Figure 1 is a side elevation of a duplex pump showing the invention applied
thereto, the tank into which the water and air are forced being shown in section.
Figure 2 is a partial plan view of the same.
Figure 3 is an enlarged sectional elevation of one of the water cylinders and the
air compressor; and
Figure 4 is a view similar to Figure 1, showing a slight modification, which will
be hereinafter referred to.
Referring to said drawings, it is to be understood that the water pump therein
illustrated is of the ordinary direct acting duplex type, A being the steam end of
the pump, which consists of two steam cylinders having the usual valve gear a, by
which the valve of each cylinder is operated by the piston rod of the other, after
the manner of this class of pumps, and B the water end of the pump, which
consists of two water cylinders 6 6 provided with the usual double acting pistons
or plungers C, the rods c of which are connected directly to the pistons of the
steam cylinders:
The water end B of the pump is provided with the usual suction chamber d,
which communicates with the water cylinders 6 and with the usual force chamber e,
into which the water is forced from the cylinders b, and from which it is discharged
through the discharge pipe D into a tank or reservoir E, against the pressure of a
volume of compressed air confined in the upper part of the tank. The parts
thus far mentioned are of the ordinary and well known construction, and will
consequently be understood by anyone familiar with this class of pumps, without
a more detailed description.
The outer end of one of the water cylinders 6 is provided with an extension F,
forming a small cylinder, the outer end of which is closed, while the inner end
opens into the cylinder b. The cylinder F is provided with an ordinary piston f,
the rod g of which is secured to the piston or plunger C of the pump, as shown in
Fig. 3. The cylinder F is provided at its outer end with valve openings l, n,
which are controlled by ordinary suction and force valves h, i, which open.
inwardly and outwardly respectively, and are provided with springs or other
suitable means by which they are normally held to their seats; the opening 1,
which is controlled by the valve h, being arranged to communicate with the open
air, while the opening n, controlled by the valve i, communicates with a pipe G,
which leads to the upper portion of the tank E.
The operation of the combined water pump and air compressor thus constructed
is as follows: The pump being set in motion, the water will be drawn from the
suction chamber d.into the water cylinders 6, from which it will be forced into
the force chamber e, and discharged through the pipe D into the tank E, against
the pressure of the volume of air confined in the upper portion of the tank in the
usual manner. The water thus forced into the tank will then be drawn off
through the pipe H, and conducted to the place of use under the pressure due to
the volume of air compressed in the upper part of the tank.
As before stated, the air contained in the upper part of the tank E is gradually
absorbed and carried off by the water as the latter is drawn from the tank, so that
if no means were provided to maintain the supply of air in the tank, it would be
gradually diminished, and its pressure thus destroyed, so that the water would
issue from the tank under less than the proper degree of pressure. This result is
avoided by the operation of the piston f. As the plunger C makes its stroke
toward the steam end of the pump, a quantity of air is drawn into the cylinder F
by its piston f, and upon the return stroke of the plunger C, the air thus drawn
into the cylinder F is compressed by the piston f, and forced past the valve i, and,

page_text: through the pipe G, into the upper portion of the tank E, thus constantly supplying
air to the tank, to compensate for the air absorbed and carried out by the water,
and maintaining the water under the proper degree of pressure.
It will be observed that by this arrangement, no extra labour is thrown upon
the pump at the end of its strokes in either direction, the resistance at the end
of the strokes in each direction being just equal to the pressure of the water
against the full area of the plungers C, and no more.
By this arrangement also, no air is allowed to enter the water cylinders, and
consequently a smooth and quiet action of the pump is secured.
By this arrangement also, no trouble is experienced from the heating or lack of
proper lubrication of the air compressing cylinder F, as the water from the
cylinder 6 follows the piston f, so as to enter the air cylinder and keep it properly
cooled and lubricated.
In order that all the air drawn into the cylinder F may be compressed and
forced out into the tank E, it is often desirable that a quantity of water should be
admitted to this cylinder in front of the piston f, to fill the clearance between the
piston and the head of the cylinder. For this purpose, a small trough or
receptacle k may be provided at the end of the cylinder, into which a small
quantity of water can be poured, so that as the valve h is opened to admit air to
the cylinder upon the suction stroke of the piston f, a small quantity of water will
be allowed to flow past the valve into the cylinder.
If, at any time, it should be desired to stop the forcing of air into the tank E, it
can readily be accomplished by simply fastening the valve h in its opened
position. This can readily be done by means of a screw, as m, arranged to be
turned inward, so as to abut against the end of the valve rod, and move and hold
the valve away from its seat; or, if preferred, the same result can be accomplished
by locating the valve h in a pipe, through which the air is allowed to enter the
cylinder, said pipe being provided with a cock by which the supply of air can be
shut off if desired.
As shown in Figures 1, 2 and 3, the pipe G leads from the cylinder F directly to
the top of the tank. This arrangement, however, is not necessary. If preferred,
the pipe G may enter the pipe D instead of the tank, as shown in figure 4. In this
case, the air will be mingled with the water before the latter enters the tank, and
will simply rise through the water and accumulate in the top of the tank.
Although, as herein shown, only one of the water cylinders b is provided with
an air compressing cylinder, it is of course to be understood that both of the water
cylinders may be provided with these air compressing cylinders, if in any case it
should be found necessary or desirable to do so.
Although the invention is herein shown as applied to a direct acting duplex
pump, it will readily be understood that it is not limited in its application to a
pump of that type, but may be applied to a single pump, or to a pump that is not
direct acting, with equally good results. It will also be seen that the invention is
not limited in its application to supplying air and water to the same tank, in
order to maintain the water under pressure, but may be used in any case where it
is desired to pump water, and at the same time compress air for any purpose.
While a simple way is shown in the illustration, of connecting the piston rod of
the compressor with the plunger C, any other convenient connection may be
employed for conveying the reciprocating motion of the pump to the compressor
piston f.
Having now particularly described and ascertained the nature of the said
Invention, and in what manner the same is to be performed, as communicated to
me by my Foreign Correspondent, I declare that what I claim is
1. A combined water pump and air compressor, consisting of a water cylinder
and its piston or plunger, and an air cylinder and its piston or plunger, the two
cylinders being so arranged that one end of the latter communicates with one end
of the former, substantially as described.

page_text: 2. The combination with a water cylinder and its piston or plunger, of an air
cylinder arranged at the end of, and opening into the water cylinder, and having its
piston or plunger connected to the piston or plunger, or piston or plunger-rod, of
the water cylinder, substantially as described.
3. The combination with a duplex pump, as A B, of an air cylinder, as F,
arranged at the end of, and opening into one of the water cylinders, and having its
piston or plunger connected to one of the pistons or plungers, or piston or plunger
rods, of the water cylinders, substantially as described.
4. A combined water-pump and air compressor, consisting of a water cylinder
having a moving piston or plunger, and an air cylinder and its piston or plunger,
the two being so arranged that the water pressure in the pump is communicated
to one side of the piston or plunger of the air cylinder, substantially as described.
Dated this 17th day of Navambou 100K