A New or Improved Compressed Air Refrigerating Machine.
Year: 1897

page_text: Date of Application, 7th Sept., 1897-Accepted, 30th Oct., 1897
COMPLETE SPECIFICATION.
A New or Improved Compressed Air Refrigerating Machine.
I, HUGO BERNARD ROELKER, Mechanical Engineer of No. 41 Maiden Lane, in
the City of New York, and State of New York, United States of America, 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 certain improvements in the refrigerating machine of
the type or character known as the "Allen Compressed Air Refrigerating
Machine" in which air is artificially refrigerated by mechanical expansion of
the same in a cylinder with a piston and with distributing valves which piston by
a piston rod cross-head, etc., is linked to a crank-shaft which offers resistance by
being also connected to an air compressor. The air compressor takes air which
is contained in a system of refrigerating and conveying pipes and which is of con-
siderably more than atmospheric pressure and compresses it, thereby heating the
air in direct proportion to the labour expended upon it by the compressor.
Then it forces the hot compressed air into a cooling coil surrounded by circulated
water and the cooled compressed air is then led to the expander cylinder where
the, valves admit the same into the cylinder and upon the piston in the same
during a portion of the stroke.
Then they shut off the inlet and the combination of the motion of the piston to
the end of the cylinder expands the air at diminishing pressure and causes
refrigeration of the same proportionate to the labour performed upon the piston
during the expansion.
In addition to the compressor cooling-coil and expander there is required in
such a machine a steam-engine which supplies the excess of power which the
compressor requires above that supplied by the expander also the power required
to overcome friction. There is also a primary air-pump which takes air from the
atmosphere and charges the refrigerating pipe system with the initial air-pressure.
Also a water-pump which supplies the circulating cooling water.
Also a trap
which removes the atmospheric water from the air put in by the primary air-
pump. Also one trap which removes the lubricating oil from the expanded
refrigerated air before this enters the cold pipes. Also various pipes for con-
veying water and air to the various operations.
My invention is designed to carry out these objects and it consists of a
refrigerating machine in which two air-compressing and expanding cylinders are
arranged alongside of each other at the front of the machine, while the steam
cylinder is arranged at the rear of the same said cylinders being inclined towards
each other and provided with cross-heads and connecting-rods linked to cranks
on a crank-shaft above the cylinders which cranks are arranged at an angle of
120 to 150° towards each other.
The invention consists further of a refrigerating machine in which the air-
compressing and expanding cylinders are arranged in the front and the steam-
cylinder at the rear of the machine, a crank-shaft supported above said cylinders

page_text: and cranks on said crank-shaft and two eccentrics at the outer end
of said crank-shaft the angles formed by the centre-line of the air-cylinder
and steam-cylinder supplying inuneation with the angles at which the cranks
are placed towards each other the requirell valve-motions so that the five slide-
valves of the three cylinders are driven by two rock-shafts each of which is
actuated by one of the eccentrics on the crank-shaft.
The invention consists further of certain details of construction and com-
bination of parts which will be fully described hereinafter and finally pointed
out in the claims.
By the practical use of the Allen Compressed Air Refrigerating Machine it
was found that machines which are to be used on vessels and which require a
comparatively small refrigerating power must occupy the smallest possible floor-
space and must be able to run at a high number of revolutions at a high primary
air pressure and with almost absolute noiselessness. These machines also have to
run at fast or slow speed with uniform motion so as to require little balancing
effect from a fly-wheel and with small strain on bearings.
In the machine constructed by me and in which my inventions are applied these
especial necessities are obtained by the peculiar placing together of the com-
pressor and expander cylinders and of a steam cylinder at certain angles of centre
lines and by crank pin angles so that the stresses exerted by their pistons nearly
balance and exert but little pressure on the fixed bearings and require only a
small balance wheel when working at slow speed. These same angles make it
possible to use slide-valves (also of peculiar construction) instead of the usual
conical lift-valves for the inlet and the outlet of the air compressor and to do
this without additional multiplication of moving parts.
These slide-valves of the compressor provide a full air inlet opening from the
air suction-pipe during the suction stroke then a complete closing off during
the act of compression then an opening to the high pressure part while the piston
pushes the compressed air out, then a complete closing off while the high pressure
air in port and clearance expands to suction pressure during the first return move-
ment of piston and then again a full suction opening from the air suction pipe.
All this for a double acting cylinder.
The fixed bearings are placed outside of all the crank pins because this still
further relieves them from the unbalanced portion of the crank pin pressures by
dividing them always upon both the bearings instead of increasing the strain by
extra leverage as is done when crank-pins are located outside of fixed bearings
which are at comparatively close distances.
Other practical advantages are obtained by the exposed position of the air-
cylinders which require closer looking after than any other part of an air-ice
machine.
This combination makes it possible to run the machine noiselessly at high
speed and with high pressures with little wear of parts and little attention and at
same time a lightness and smallness are obtained by the compact position of parts
which all make this combination a very useful one.
The drawings accompanying this specification show practically all parts com-
posing this machine but the minor parts upon the arrangement of which I do not
lay stress are not lettered.
In the accompanying drawings:-
Fig. 1 represents a side-elevation of my improved Dense-Air Refrigerating
Machine.
Fig. 2 is also a side elevation partly in section through one of the air-
cylinders and its slide-valves and the supporting frame of the machine.
Fig. 3 is a front-elevation of the machine, and
Fig. 4 is a plan view of the supporting-frame of my improved refrigerating
machine.
Similar letters of reference indicate corresponding parts.
Referring to the drawings-A represents the supporting frame of my improved

page_text: refrigerating machine which is composed of two upright side-standards A¹ that
are connected at their base portion and at the upper ends. The base and side-
standards A are transversely connected by a web A2 which is cast with ..two
inclined seats as at its front part and an inclined seat a³ at its rear part which
seats serve as supports respectively for the air compressing and expanding
cylinders G and H and a steam-cylinder I. The side-standards A¹ are further
provided at their upper ends with journal-bearings for a crank-shaft C which is
provided between the side standards with two cranks C¹ C on the crank-shaft C
a fly-wheel F and with two eccentrics E E at the outer end of the shaft C. To
the front seats a² of the transverse web A³ are attached side-ways of each other
and at suitable inclination to the transverse plane passing through the centre of
the crank-shaft the air-compressing and expanding cylinders G and H while the
steam cylinder I is supported in the rear seats a³ of the supporting web A³ as
shown in Fig. 2. Above the inclined seats of the cylinders are arranged on the
transverse web Aª inclined guides a as a for the cross-heads G H¹ and I¹ of the
air and steam cylinders. The piston-rods of the three cylinders are separately
connected to their corresponding cross-heads and the latter linked by connecting-
rods g¹¹¹ to crank pins g h and i on the cranks C¹ C³ as shown in dotted lines in
Fig. 3.
The proper angle of inclination at which the air and steam cylinders are to be
supported towards each other on the transverse web A2 of the frame is preferably
an angle of from 25 to 50 degrees. The valve-face of the steam cylinders I is
arranged at right angles to the valve faces of the air-cylinders as shown in
Figs. 1 and 2 which in connection with the inclination of the air and steam-
cylinders towards each other permits that the connecting rod of the slide-valve of
the steam cylinder can be applied to an arm on the same rock-shaft to which the
connecting rods of the main valves of the air cylinders are applied. The relative
positions of the steam cylinder I to the air-expanding and compressing
cylinders G and H also furnishes a favourable angle for balancing the power
which is supplied by the steam-cylinder and the air-expanding cylinder with the
force consumed by the air-compressing cylinder during each rotation of the crank-
shaft.
The air-expanding cylinder H is provided ith the usual main slide-valve and
cut-off valve while the air-compressing cylinder G is provided with a main slide-
valve and with a top slide valve similar to a cut-off valve instead of the usual
conically-seated lift valves. The crank C of the air-compressing cylinder G is
arranged at an angle of from 120 to 150° to the crank C of the air-expanding
cylinder H so that a single eccentric E and a single rock-shaft R with arms r god guilt
can operate the main slide-valves of the steam cylinder and of the air-compressing
and expanding cylinders for producing the proper distribution of pressure and
exhaust. The second eccentric E' and a second rock-shaft R' with arms is
arranged for operating the top-slide valves of the air compressing and expanding
cylinders so that the air-pressure is cut off at the proper point in the latter before
expansion and that the air-compressing cylinder be opened to the general air-
pressure when the piston has compressed the air to the pressure prevailing in
the compressed air cooler. It appears from the foregoing therefore that the two
eccentrics E E which are arranged at the outer end of the crank shaft C operate
in connection with the two rock-shafts R R the five slide-valves of the three
working cylinders G H and I which act on the crank shaft C at different angles
and crank positions. The other accessories of the machine are located as
follows: The casing containing the cooling coil submerged in water is located
under the eccentrics E E and is visible on the drawing only by a few flange
outlines on Figs. 1 and 3.
The primary air-pump is attached to the left side of the air-compressor G (Fig. 3).
The water circulating pump to the right side of the same compressor (Figs. 1 and 3).
The atmospheric water trap is located at the front part of the frame casing as shown
in Fig. 1 and the lubricating oil trap at the left of expander cylinder H in Fig 3.

page_text: The other accessories of the machine are located as follows:-A pipe marked Y
conveys the compressed hot air to the cooling coil which is contained in the water-
filled casing Z. This is visible on the drawings only by a few outlines in
Figs. 1 and 3. The pipe which conveys the water cooled compressed air from unis
cooling coil to the expander cylinder is marked W (Fig. 3).
The primary air-pump X (Fig. 3) is composed of a plain plunger pump with
two valves and is shown in the left hand side of the water jacket of the air com-
pressor G. It draws air from the atmosphere and conveys it through a pipe V
(Figs. 1 and 3) to the atmospheric water-trap U (Figs. 1 and 3) from the fower
end of which the dry primarily compressed air is conveyed by the pipe T
(Figs. 1 and 3) to the inlet pipe S of the compressor G which pipe comes from
the refrigerated system conveying the air back to another manipulation in the
ice machine.
The water circulating pump R (Figs. 1 and 3) is shown on the right hand of
the same compressor. It is constructed as a usual plunger pump with two valves.
It receives water through suction pipe L with vacuum barrel K. It delivers
cooling water first into the jacket of the air compressor and from this the water
passes through pipe Q to the atmospheric water-trap U and then to the water
casing Z of the cooling coil after which it runs off through a pipe (not shown).
The refrigerated air passes out from the expander cylinder directly through,
the lubricating oil trap and is conveyed to its work by the pipe M (Fig. 3)
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is:-
1. In a compressed air-refrigerating machine the combination of air compressing
and expanding cylinders arranged alongside of each other at one side of the
machine a steam cylinder arranged at the other side of the machine the air
cylinders and the steam cylinder being arranged at an angle of 25° to 50°
towards each other a crank shaft supported above the cylinders and two cranks on
said crank-shaft arranged at an angle of 120 to 150° towards each other one crank
being linked to the piston-rod of the air expanding cylinder & the other to the
piston-rods of the steam and air-compressing cylinders substantially as set forth.
2. In a compresed air refrigerating machine the combination of an
compressing and an expanding cylinder and a steam cylinder arranged on an
upright frame a crank-shaft supported above said cylinders, three crank-pins on
said crank shaft one connected with the connecting-rod of the air-expanding
cylinder and the other two with the connecting rods of the steam and air-com-
pressing cylinders said crank shaft being supported in journal-bearings of the
supporting frame outside of said cranks substantially as set forth.
air-
3. In a compressed air refrigerating machine the combination with an upright
supporting frame of air-compressing and expanding cylinders arranged at one
side and a steam cylinder arranged at the other side of said frame the two air
cylinders being supported at a suitable angle of inclination towards the steam-
cylinder a crank shaft supported above the air and steam cylinders an eccentric
on said crank shaft a rock-shaft operated by said eccentric on said crank-shaft and
connecting rods between the rock-shaft and the slide valves of the air and steam
cylinders substantially as set forth.
4. In a compressed air refrigerating machine the combination with an upright
supporting frame of air compressing and expanding cylinders arranged at one
side and a steam cylinder arranged at the other side of said frame the two air
cylinders being supported at a suitable angle of inclination towards the steam
cylinder and the valve face of the air cylinders located at right angles to the valve-
face of the steam cylinders a crank shaft supported above the air and steam
cylinders an eccentric on said crank shaft a rock shaft operated by said eccentric
on said crank-shaft and connecting rods between the rock-shaft and the slide valves
of the air and steam cylinders substantially as set forth.

page_text: 5. In a compressed air refrigerating machine the combination with an upright
supporting frame of au air compressing an air-expanding and a steam cylinder a
crank shaft supported above said cylinders and provided with three crank pins
one for the connecting rod of the air-expanding cylinder and the other two for
the connecting rods of the steam and air-compressing cylinders, two eccentrics on
said crank-shaft two rock-shafts operated by said eccentrics and connecting rods
between the main and top slide valves of the three cylinders so that said slide
valves are operated by two rock shafts only substantially as set forth.
ח
1.
Jf Contember 1897
TONGUE & BIRKBECK,
Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.