Improvements in Cold Air Refrigerating Machines.
Year: 1888

page_text: Date of Application, 27th Aug., 1888
Complete Specification Left, 27th May, 1889-Accepted, 6th July, 1889
Improvements in Cold Air Refrigerating Machines.
I, WILLIAM GARDEN of 60 Graham Road, Dalston in the County of Middlesex,
Engineer, do hereby declare the nature of this invention to be as follows
My invention relates to machinery for producing cold air for refrigerating purposes
in which the air is first compressed, then cooled, and expanded to produce the intense
cold required.
Upon a suitable bed plate are mounted at opposite ends a compression and
expansion cylinder, the pistons of which are operated from a common crank or
otherwise.
The air compression cylinder is open at both ends, said ends being in communication
with a front and back compression chamber. These two chambers are filled to the
desired height with water which also fills the cylinder so that the piston travels in
solid water and by forcing the water before it in one direction compresses the air in
say the back chamber from whence it passes through an outlet valve, while the
water being exhausted or partly exhausted away from the front chamber allows air
to be drawn into same, ready for the return stroke of the piston when the water
level being raised the air in that is compressed and also passed away through an
outlet valve, the operations being of course repeated at each stroke of the piston.
In this way the piston does not come in contact with the air but is surrounded
by a body of liquid which is moved by it, and in itself forms a piston above
which the air is compressed, so that no loss of compressed air by leakage through
an ill fitting piston can take place, while any heat generated by friction in the
cylinder is not communicated to the air but is absorbed by the liquid, while the
liquid piston will enable all the compressed air to be forced out, instead of leaving a
quantity which cannot be removed owing to the clearance space required with the
ordinary piston, and which on expanding reduces the amount of air which can be
drawn into the cylinder.
The suction or inlet valves for the compression chamber work vertically instead of
as is very general horizontally, and consist of a flat disc having a suitable packing on
its face and a spindle travelling in guides, the disc being held up to its seat preferably
by rubber bands, the tension of which will be just sufficient to return them to their
seats after the suction of air has taken place.
The outlet or delivery valves consist of balls or spheres of rubber or other
material which while on their seats close the outlets from the compression chambers.
The compressed air from either chamber alternately lifts and passes through them and
through a pipe to the cooling chamber which may he conveniently situated beneath
the bed plate of the machine.
In former refrigerators working on what is known as the wet compression principle,
the water delivered from the circulating pump was partly injected into the compressor
and partly into the cooling chamber, there were no proper mans of regulating
the supply to the compressor, which being continuous occasioned loss through more
water having to be used than necessary, or through the dense air being cooled
through a less range in temperature. I propose to inject all the water from the
ordinary circulating pump into the cooling chamber, thus having the full body of
circulating water to abstract the remaining heat of compression and then to pass a
regulated amount through a pipe from the bottom of said chamber into each
compression chamber. The pressure in said cooling chamber is sufficient to force
this water into the compression chambers as the compression commences, it being
delivered into each chamber through suitable valves in the form of spray at the
time of compression only. These valves may be operated from some moving part

page_text: so as to cut off the supply at the desired moment, though it will automatically cease
of itself when the air in the compression chamber has reached its point of greatest
compression as the pressure will then be the same as that in the cooling chamber.
This water serves to take up some of the heat generated in the air by the compression,
and also to replenish the water in the chamber which may have been wasted down the
air discharge passage.
It gives an almost isothermic condition of the air during
compression, thus economizing power in compressing the air as not only is less
required for doing the work of compression but the heat so generated being practically
absorbed by the body of water injected, the excess of moisture held in suspension by
the air is deposited immediately, instead of as in other arrangements where the
temperature of the air is allowed to rise, the increment of heat being absorbed by the
moisture held in suspension, thus making it more difficult to get rid of, as it is liable
to pass through the machine into the air expansion cylinder, appearing there in the
form of snow and blocking the ports besides releasing a certain amount of heat of
condensation. The cooling chamber is provided with a number of screens of perforated
metal or other material, gauze or the like, over which the water from the circulating
pump is caused to run as the air is forced through them. From the cooling chamber
the dense air passes to the expansion cylinder. The cylinder generally in use for
expanding this air is similar to that of an ordinary steam engine. Different makers
have employed different devices for overcoming the friction due to pressure on an
ordinary slide valve, some having adopted the expedient of separate inlet and outlet
valves, the inlet valves working in the ordinary way, while the outlet valves have to
be kept up to the face by mechanical means, usually with set screws. The objections
to this arrangement of valves are obvious. For instance, there is an increase of gear
required for actuating the valves as well as the risk of setting the screws too tight
when the friction causing them to heat and the cold air impinging against them makes
them very liable to break, or if not, to warp or buckle, allowing the dense air
to escape into the cold air trunks, one of the greatest evils to be avoided in dry air
refrigeration.
The cylinder I propose to employ is surrounded by a jacket or casing, around
which the dense air circulates before passing into it. In this way the cylinder being
surrounded by a body of dense air at a uniform temperature, irregular contraction of
the walls of same and consequent undue friction on the piston is avoided. From this
jacket the air passes into a hollow slide valve which in its reciprocation brings its own
ports to correspond with ports at either end of the cylinder and allows the air to pass
alternately to either side of the piston to be expanded, the same ports in the cylinder
serving as discharge passages when the hollow slide valve uncovers them.
discharge from either end may take place into a common chamber from which passes
a pipe to carry away the cold air.
The
The hollow slide valve is supported on suitable brackets, and its face is kept close to
the cylinder by means of a pair of cranked levers kept apart by a spring, the ends of
said levers carrying rollers which press against the valve and take up the friction
The slide valve may be operated from a cam on the main shaft or in any
suitable way.
of same.
Dated this 27th day of Angust 1888
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, Loudon.
COMPLETE SPECIFICATION.
Improvements in Cold Air Refrigerating Machines.
WILLIAM GARDEN formerly of 60 Graham Road but now of 102 Dalston Lane
Dalston 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:-
My Invention relates to improvements in machinery for producing cold air for

page_text: improvements.
Figure 2 is a plan view of same.
Figure 3 is a right hand end elevation of same.
Figure 4 is a left hand end elevation.
Figure is an enlarged view of one of the valves employed.
Figure 6 is an elevation partly in section of the compression cylinder on an enlarged
scale.
Figure 7 is a plan view of same shewing also two sections on the lines to 20
and yy of Figure 6 respectively the last section however having the ball valve
removed.
Figure in its lower portion is an end elevation of Figure 6 looking from the
right hand side and in its upper part is a section on the line zz of same Figure.
Since filing my Provisional Specification I have found by experiment that the air
compression cylinder therein described in which the air was compressed by the piston
through the medium of a body of water is practically unworkable and I therefore
employ an air compression cylinder and piston such as ordinarily used in this class of
machine, and modify the inlet valves accordingly.
The cylinder A is mounted at one end of a bed plate, at the other end of which
is the air expansion cylinder B the pistons of both being operated from a common
crank shaft C which is driven from a pulley in
Beneath the bed
suitable manner.
any
plate I place the cooling chamber D.
The cylinder A. has two passages a a and a a¹ at either end leading therefrom as
shown in Figures 67 and 8 and in these are located the air inlet valves b
and b¹ b¹.
These valves I prefer to make practically in the form shown though many other
ordinary forms may be employed as the employment of vertical valves is unnecessary
except a water compressor cylinder is used. The valves are leather or vulcanized fire
flap valves as shown and for quickness of action I prefer to connect each with its
corresponding valve at the other end of the cylinder by means of an elastic cord 62
as shown so that as the pair at one end are opened or lifted by the suction of
the piston the pair at the opposite end are assisted to rapidly close as the compression
there begins.
The outlet or delivery valves consist of balls d d and dd resting in seats in
casings dat either end. These balls are covered by a four armed piece d³ which
leaves them room to lift and which is held in position by a regulating screw d passing
through the top of the casing. The casings dd communicate with a common
outlet passage e to which is connected a pipe E which conveys the compressed air to
the cooling chamber D.
In cold air machines as at present constructed and working on what is known as
the wet compression principle the water delivered from the circulating pump (such as
shown at F) is partly injected into the compressor and partly into the cooling chamber.
There are no proper means of regulating the supply to the compressor which being
continuous occasions loss through more water having to be used than necessary or
through the dense air being cooled through a less range in temperature. I inject
all the water from the ordinary circulating pump F first into the cooling chamber D
thus having the full body of circulating water to abstract the remaining heat of
compression from the air and then pass a regulated amount through pipes f
connected with the bottom of said chamber and through pipes and into the
cylinder A. at either end of same. The pressure in said cooling chamber is sufficient
to force this water into the cylinder at either side of the piston as the compression
commences it being delivered there in the form of spray at the time of compression

page_text: only. To regulate this supply the pipe communicates with a valve box G shewn
in enlarged view in Figure 5 in which is a slide valve g which alternately opens
and closes the openings to chambers g g communicating respectively with the
pipes f In this way as the valve is operated the water from the pipe is
admitted alternately to the pipe f¹ and to the rear end of the cylinder and to the
pipe and the forward end as the piston travels in those directions and is cut
off as the compression is completed though it would automatically cease when the
air in the compression chamber has reached its point of greatest compression as the
pressure is then the same as in the cooling chamber. This water injected serves
to take up some of the heat generated in the air by the compression. It gives an
almost isothermic condition of the air during compression, thus economising power,
as not only is less required for doing the work of compression but the heat so
generated being practically absorbed by the body of water injected the excess of
moisture held in suspension by the air is deposited immediately instead of as in
other arrangements where the temperature of the air is allowed to rise, the increment
of heat being absorbed by the inoisture held in suspension thus making it more
difficult to get rid of as it is liable to pass through the machine into the air expansion
cylinder appearing there in the form of snow and blocking the ports besides releasing
a certain amount of heat of condensation.
The water injected into the cylinder is expelled by the piston behind the compressed
air at each stroke and passes down the pipe E into the well E¹ in which is an ordinary
float valve E2 by which it is drawn off, the float valve always remaining covered by
the water and only closing if the level of same falls. This well E' also receives the
overflow water from the cooling chamber.
The rod of the slide may be conveniently operated from a sliding bar / travelling
on pins which are affixed to the side of a beam H forming part of the frame-
work. The under side of this beam H forms the upper bearing face for a link cross
head I travelling on the bed plate and which is reciprocated by the crank shaft C.
This link I in its travel strikes the ends of the sliding bar and thus operates the
slide valve g.
"
The compressed air passes from the pipe E into the cooling chamber D which is
provided with a number of screens of perforated metal or gauze having raised
sides which will enable them to hold the water passed on to the uppermost one
through the pipe from the pump F which takes it from a suitable source of
supply.
The mesh of these screens is fine enough to retain the water by capillary attraction
(aided by the rising air). It overflows from the upper to the lower ones as shown by
the arrows.
The air as it is cooled by rising through these screens passes by a pipe K
to the expansion cylinder B.
This cylinder I surround by a jacket or casing L into which the dense air first
passes so that irregular contraction of the walls of the cylinder and consequent
undue friction on the piston is avoided as the former is always surrounded by a
body of dense air at a uniform temperature.
In this way the dense air is in contact with the outside of the cylinder so that
the cooling effect of the cylinder is utilized to deposit moisture from the dense air on
the outside of its walls which is of advantage as the dense air is thus lowered in
temperature and rendered drier.
From this casing the dense air passes by the ports or into a hollow slide
valve M. which is reciprocated as hereinafter described so as to bring its own ports mm²
to correspond with said ports. The reciprocation of the valve will carry the ports m m¹
alternately over the ports 12 13 communicating with either end of the cylinder B so
that the dense air is admitted to either side of the piston B' to be expanded in
the usual way the ports 12 serving also as the outlet ports as they are uncovered by
the slide valve.
Say for instance that the piston B₁ is in the position shown in Figure 2 which
shows it as having moved slightly forward. The dense air is admitted behind it

page_text: through the ports 11 m² m and while the air in front of it which has just
been expanded is driven out through the port which has been uncovered by the
slide valve M.
is
The piston makes a forward travel of about 3 inches and the inlet port
then cut off by the slide valve, the piston in its remaining travel expanding the air
which it has taken in.
The cold air leaving the port may be conveniently received into a casing (indicated
at N by dotted lines) which encloses the slide valve and from whence it is carried off
by a pipe to use for the usual refrigerating purposes.
Upon the return movement of the piston B the slide valve will bring its ports min¹
to correspond with the ports ³ respectively thus uncovering the port for the
discharge of the last expanded air.
This form of valve necessitates its being held against the cylinder face by mechanical
means and to accomplish this without undue friction I arrange it in the following
manner. The slide M is supported by ledges nn formed on the outside of the
casing L and its face is held to its work by means of rollers o o¹ pressed upon it by
levers p p.
These levers ppl have grooves p² p² formed in their rear ends (see Figure 2) in
which bear the rounded ends of steel blocks p³ p³ on which they pivot. These
blocks are held in bridge pieces 77 supported by posts q¹ g' q₁ q¹ which are
secured to the casing L. These steel blocks are adjustable in the bridge pieces by
means of screws and when adjusted are held by the set screws. The other
ends of the levers p p are held down by a spring s carried by a bridge piece t
supported by posts t₁t secured to the casing L. The pressure of this spring on the
levers is regulated by the screw t which bears on same.
As the slide valve M is reciprocated the rollers move a short distance each way
with it and they are so placed that the movement of the valve brings them nearly
in line with the centre of the forces tending to lift the valve off its working face,
thus balancing the slide and reducing the wear on same to a minimum.
2
The slide valve M is preferably operated from a cam v on the main shaft which
bears on friction rollers v carried by a frame w attached to the rod w¹ of the valve.
The frame w to permit of its reciprocation is slotted to allow the crank shaft C to pass
through. This cam is shaped as shewn so that a "dwell" is given to the slide M
"dwell'
when its ports are in communication with the cylinder ports as well as a
when the inlet port is closed to allow of the expansion taking place. It has a slight
motion however during these "dwells so that the dead weight of the slide has not
to be overcome when the cut off (which is rapid) takes place. Said shaft carries
outside of this an eccentric 2 which operates the rod of the pump F.
The operation of the apparatus will be evident from the foregoing description but
it may be explained that the air is drawn into the compression cylinder A. by the
suction of the piston through the valves bor the valves and on the return
stroke is compressed during which a spray of water is forced into the cylinder as
described and forced through the outlet valves dor d' d' into the passage e and
from thence down the pipe E into the cooling chamber D up which it rises
through the perforated screens to the pipe K and the expansion cylinder.
Although I have shown the best means known to me at the present time for
carrying my Invention into effect I do not desire to limit myself to the exact form
of apparatus shown and described but:-
Having now particularly described 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 :-
1st. A cold air refrigerating machine in which the water from the circulating
pump is injected first into the cooling chamber and a regulated amount then
forced by the pressure in said chamber into the compression cylinder on either
side of the piston at the time of compression only substantially as described.

page_text: 2. A cold air refrigerating machine having a cooling chamber consisting of a
number of screens of perforated metal of tray form on to the uppermost of which
water is pumped and through which the air rises substantially as described.
3. A cold air refrigerating machine having an expansion cylinder surrounded by
a jacket or casing in which the dense air circulates before expansion substantially as
described.
4. A cold air refrigerating machine having a slide valve for the expansion
cylinder consisting of a hollow casing into which the dense air is admitted through
ports which are brougnt alternately over ports communicating with either end of
the cylinder said cylinder ports acting both as inlet and exhaust ports as they are
covered or uncovered the slide valve working on rollers held to it by adjustable
levers substantially as described.
Dated this 27th day of May 1880
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London, Agent for the Applicant.