Improvements in Refrigerating Apparatus.
Year: 1893

page_text: Date of Application, 13th Mar., 1893-Accepted, 24th Feb., 1894
Improvements in Refrigerating Apparatus.
A communication from GEORG KRAUSCHITZ, of Lützowstrasse 12, Berlin, in the
Empire of Germany, Engineer.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Chartered Patent Agent, 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 refrigerating apparatus wherein a constant vacuum in
the absorption-vessel, and corresponding thereto, a fixed and uniform temperature
in the refrigerating chamber, even under the greatest irregularities and most
variable conditions of working in the apparatus, are automatically produced and
maintained by special devices, such that in proportion to the variations in the
vacuum and temperature, that is to say, to the smaller or greater degree of
rarefaction of the air in the absorption-vessel and to the higher or lower temperature
prevailing in the refrigerating chamber or in the liquid to be cooled-a single-
cylinder air-pump (Fig. 2) working with an oil-injector and provided with an oil-
intercepter and a device for the automatic removal of oil-leakage, is automatically
set in or out of action by means of a regulating device (Figs. 3 to 9 and 10); and
simultaneously, either by such regulating device or by another device (Fig. 2ª)
adapted to the same end, the said air-pump, i.e. its cut-off cock or the equivalent
thereof (arranged between the air-pump and the absorption-vessel) is opened or
closed; whereby lastly, owing to the improved form of the concentrating apparatus
employed a better and more economical use of the fuel consumed, is attained.
In the accompanying drawings, the general arrangement of the complete
refrigerating apparatus is shown in Figs. 14 1B and 1°, respectively, in sectional
side-elevation, cross-section and plan.
A is the absorption-vessel, which contains the concentrated absorbing fluid. B is
the receiver or refrigerating chamber (preferably cast in one piece with A) which
receives the concentrated fluid as it is supplied from the concentrator.
A and B
are provided with a cooling jacket, and the former with an agitator or stirring
apparatus and suitable pipe connections and the latter if similarly arranged may
also be utilized as an absorption-vessel.
C is the air-pump, necessary for the creation of a vacuum. J) is the prime-motor,
such as may be most convenient and suitable, according to the conditions of locality;
in the present instance a hydraulic motor, which operates C by means of a worm
and worm wheel. E is the apparatus operated by the vacuum in the absorption-
vessel or by the temperature in the refrigerating chamber, for setting the air-pump
in or out of action, and for simultaneously opening or closing the cut-off cock (or
its equivalent) between A. and C. F is the concentrator composed of several parts;
GG are cocks controlling the connections between A and the receivers containing
the liquid to be refrigerated.
The general working of the apparatus is as follows;-
The air-pump C driven by the prime motor D forms in the absorption-vessel A
partly filled with concentrated sulphuric acid, a sufficiently complete vacuum,
which by means of the cocks G G is extended to the receiver or receivers containing
the liquid to be refrigerated. Here, the said liquid is partially evaporated under
the influence of the vacuum, and is lowered in temperature by the abstraction,

page_text: from itself, of the heat necessary for such evaporation, so that in consequence, a
cooling and freezing effect takes place. The watery vapour, thus generated is
rapidly absorbed by the sulphuric acid in the absorption-vessel, whereby the vacuum
is rendered still more perfect.
By means of an agitator or stirring apparatus, within the absorption-vessel, a
uniform commingling of the water and sulphuric acid is brought about.
When the
dilution of the acid has reached a certain point, it must again be concentrated;
and this is effected in the concentrator F. The spent or diluted acid passes under
atmospheric pressure into the evacuated reservoir 35 and is thence conveyed, by
the heated corrugated pipe 31 to a suitable boiling-pan, where the water is driven
off by boiling. The sulphuric acid thus concentrated and rendered fit for re-use,
flows from the boiler into the receiver B and rises thence under atmospheric
pressure, into the evacuated absorption-vessel A. In this way, the acid makes, at
intervals as required, the complete circuit of the apparatus.
The device E serves, automatically, to set the air-pump and its motor in and out
of action, as well as to effect the opening and closing of the cut-off cock between
the absorption vessel A and the air-pump itself.
Fig. 2 is a vertical section, on an enlarged scale, of the air-pump C which is
an ordinary suction and force-pump (or double acting pump) and is adapted
for working with a fluid, such as is used for the purpose of ensuring the perfect
and absolute tightness of the valves and piston, and to fill up any vacant spaces
that would be injurious to the working of the apparatus, the arrangement being
such that, above the piston, there is always a certain quantity of the joint-closing
fluid, whereof part, shortly before the piston completes its stroke, passes through
the channel 1 and the adjustable port 2, and enters into the space below the piston.
Should during the periods of inaction of the air-pump C say through defect in
tightness of the suction valve by any chance any of the above named joint-closing
fluid escape below the valve, it is intercepted in the vessel 3 and when the air-pump
is again set in action, is without further trouble, at once automatically returned to
the upper part of the pump-cylinder, above the piston. To this end the suction
valve-seat is provided with a tubular extension or nozzle 4, having several notches 5
in its lower end. On the outside of the said lower end the nozzle is eularged by
ribs or feathers suitably adapted to guide a cup-shaped valve 6 which has a vertical
to and fro movement thereon its internal diameter being larger than the external
diameter of the body of the nozzle forming a ring-shaped opening so that the
valve may leave the space 5 open for free communication between the suction-
valve and the waste-fluid interceptor 3 through the nozzle 4, for the removal of
the waste-fluid and gases from 3.
When the air pump-piston rises the valve 6 is drawn against the lower end of
the nozzle and 3 being filled with the escaped joint-closing fluid, this latter will be
drawn into the nozzle 4 and hence in a well-known manner, be returned into the
cylinder above the piston. The valve being situated at the lowest point of 3
nearly the whole of its contents will thus be drawn off. The waste fluid being
thus removed, so that air or gases may be drawn through the notches 5 into the
nozzle 4 and so through the suction-valve the valve 6 will fall and displace any
remaining waste-fluid at the bottom of 3 and cause it to collect at the bottom of
the cup and close the valve and passages 5 against the passage of air, at the next
upstroke of the pump when a vacuum will again be created in the nozzle 4 and the
waste-fluid again be drawn in and past the piston as before so as entirely to empty 3.
This being done, the entire sectional area is open to the passage of the air and
gases drawn from A.
Fig. 2 represents the device (already mentioned in the introductory part of this
Specification) for automatically opening and closing the cut-off cock between the
absorption vessel A and the air-pump C and simultaneously for starting or stopping
the pump by means of the disengaging device E. The movement of the cut off
cock or its equivalent is effected by the rotation of a cam which has the form of a
screw thread 45 against the face of which bears an arm 46 which is attached to a

page_text: sleeve 47 mounted on the worm-shaft 53 in such manner as to be capable of sliding
along the shaft while not rotating with it, and being also fitted with a driver 49
diametrically opposite the arm 46. The cam or screw-thread 45 is preferably cast
in one piece with the toothed bevel-wheel 48 or driver of the stirring apparatus,
and consequently is rigidly connected with the driving shaft of the motor; whereas
the worm-shaft is divided from the driving-shaft, though in the same axial line and
free to rotate in the boss or hub of wheel 48 hollowed to receive it. The cam 45
(or bevel-wheel 48) also carries a fixed arm or driver 50 which after a half-turn of
the cam or screw-thread engages or comes into contact with the driver 49 attached
to the sleeve 47; while simultaneously therewith, and by the same half-turn of 45
the arm 46 and with it of course the sleeve 47 to which it is attached, are caused
correspondingly to move outwards by sliding along the worm shaft 53 (the amount
of their linear displacement being equal to the pitch of the screw-thread 45) and
carrying with them the vertical arm of the bell-crank lever 44 whereof the other
arm is suitably connected with the cut-off cock 54, or its equivalent, between the
absorption-vessel A and the air-pump C, whereby the said cock is opened; further
also the cam or screw-thread 45 being firmly connected with the outer end of a
spiral spring 51 having its inner end fixed to the worm-shaft 53 coils the said
spring, thereby compressing and energising it. Simultaneously by the lateral
displacement of the arm 46 sleeve 47, on the worm shaft 53 and of the bell crank
lever 44 the helical spring 52 (which is fixed to a collar on that shaft) is also
compressed and energised. The continued rotation of the driving shaft, in the
same direction, causes the rotation of the worm-shaft 53 (by spring 51) and of
the sleeve 47 now engaged by the drivers 50 and 49; and so long as that rotation
continues, the relative positions of the cam or screw-thread .45 with regard to
arm 46 sleeve 47 and bell crank lever 44 remaining unchanged the cut-off cock 54
or its equivalent remains open.
By the stopping or throwing out of action of the driving shaft, however the
reverse movement of the parts takes place; the compressed spiral spring 51 being
now released, by its recoil, causes the cam or screw-thread 45 and consequently,
the driving shaft to make a half-turn in the contrary direction, withdrawing the
driver 50 from contact with 49 and the face of the screw-thread from the arm 46,
so that the compressed coiled spring 52, by its reaction is free to thrust back into
their former positions the bell-crank lever 44, sleeve 47 and arm 46, thus closing
the cut-off cock 54, or its equivalent, between the absorption-vessel A and the
air-pump C.
Instead of a hydraulic motor, a bell-driven pulley, or its equivalent, fixed on the
undivided driving-shaft and therefore rigidly connected with the cam or screw-
thread 45, may be employed.
Figures 3 to 8 represent various modifications of the apparatus E for throwing C
into operative engagement and for operating the cut-off device 54. The said apparatus
mainly consists of a cylinder 7 with a piston 8 working therein one side of which is
constantly filled with atmospheric air; while the other is connected with an oil-
cataract 9 adapted to ensure tightness and to produce the gradual elevation of the
piston, either side of the piston, or if preferred both sides, being connected with the
coupling mechanism (comprising a valve, rheostat, friction-coupling and strap-guide
or fork etc.) by a chain, rope, lever or equivalent.
In the arrangement shown in Figure 3, the oil-cataract 9 is constantly connected
with the vacuum in A, while in the arrangement Fig. 4 it communicates with the
external air through 9. Figs. 5 to 8 illustrate an arrangement in which the
connection is established alternately with the vacuum and the atmosphere.
According as the apparatus E is arranged as illustrated in Fig. 3 or as shown in
Figs. 5 to 8, when the vacuum is reduced in the absorber the piston working
within 7 will either move outwardly by the weight of the piston or inwardly by
atmospheric pressure and thereby operate the coupling-mechanism in such a manner
that the air or vacuum-pump is started gradually. This pump is then maintained
in operation as long as necessary to obtain the normal degree of rarefaction of air,

page_text: after which the piston forced in the opposite direction by the excess of atmospheric
pressure throws the pump out of gear again.
Fig. 4 represents an arrangement enabling the pump to be set in operation by
electricity i.e. by the insertion of a resistance into the circuit of a suitable electro-
motor. The electrical current is turned on or off, as required, by means of a
switch-diaphragm 10, one side of which is constantly connected with A by a
pipe 19 in such a manner that when the vacuum is reduced the diaphragm is
pressed outwardly when, through the medium of the contacts 11 and 12 a circuit is
closed which comprises the solenoid 13 surrounding the cylinder 7, the consequence
being that the iron piston 8 is drawn inwardly within 7, whereby the lever of the
resistance-box 14 and then the electro-motor and the pump connected therewith
are set in operation.
When the normal vacuum is obtained in A the diaphragm is by atmospheric
pressure pressed inwards whereby the circuit is broken so that the piston may
re-descend under the action of the weight 15 and throw the electro-motor out of
operation.
The electrical arrangement herein described instead of operating a resistance in
the circuit of an electro-motor in the manner stated, may similarly actuate any
suitable coupling-mechanism that may be employed for operating the pump, and
the rheostat may also if desired, be operated in connection with arrangements such
as are shown in Figs. 3, and 5 to 8.
Figure 6 shows the apparatus with a modified arrangement of the oil-cataract.
Figures 7 and 8 also represent modifications of the oil-cataract and at the same
time illustrate the manner of operating the air or vacuum pumps by means of
motion-transmission gearing.
The piston and piston-rod of the apparatus E are connected with the cut-off
device 54 (as shown in dotted lines in Figures 14 and 3) in such a manner that
when the pump is set in motion the cock or equivalent 54 is at the same time
opened while when the operation of the pump is stopped such cock or equivalent is
thereby closed.
All the apparatus herein mentioned are provided with arrangements 16 for the
reception and collection of the oil escaping or oozing out of 7 and for conveying
such oil back into 9. The object of the slide-valve shown on an enlarged scale in
Fig. 9 is to connect the oil-cataract of the coupling apparatus represented in
Figures 5 to 8 with the absorber A but not until the vacuum in the latter has
fallen below the normal degree, the connection in the reverse case being established
with the atmospheric air.
The slide-valve consists of a case 17 upon which a diaphragm 18 is screwed in
such a manner that the hollow space formed thereby stands constantly connected
with the absorber through the opening 19. On the opposite side of the diaphragm
there is arranged an adjustable valve 20, a guide or seat for which is provided in
another valve 21 located above 20. The valve 21 is at its lower end tightly closed
against the casing 23 by a diaphragm 22, and the remaining annular space 39
communicates with the cataract 9 through the channel 25, 24. So long as there is
a normal vacuum in A, the valve 21 closes the channel or port 26, 27 communicating
with A through the opening 19 while the other valve 20 admits atmospheric air
into 9 through the openings 28 and the channel or port 24, 25. When however the
vacuum falls below the normal state, 18 is pressed outwardly, 20 is closed,
21 opened, and a connection is established between A and 9 by 24, 25, 26, 27 and 19,
with the result that 8 being pressed into 7, the coupling-mechanism and consequently
the pump itself are set in operation. As soon as the normal vacuum is restored,
18 is once more pressed inwards 20 opened, 21 closed and 8 enabled to move in the
opposite direction either by its own weight or under the action of a spring
atmospheric air again having access to 9, whereby the gearing is disconnected and
the pump stopped.
As has been stated at the commencement of the Specification, the automatic
connection and disconnection of the vacuum pump employed to produce the desired

page_text: vacuum in the absorber, and the simultaneous opening and closing of the cut-off
device 54 may either be produced by the vacuum itself, or by the influence of the
temperature prevailing in the space or chamber or in the liquid to be cooled. For
this purpose there is provided in the cooling-chamber or in the liquid to be cooled
a suitable thermometer adapted in a well-known manner to close an electrical
circuit whenever the temperature arrives at a predetermined degree. Such a
circuit will comprise a reversing-valve K connected with the apparatus E. The
valve-chest as illustrated in Figures 10 and 11 is connected by the channel or
port 37 with the cataract-chamber 9 while in addition to that it may communicate
through the valves 38 and 43 alternately with the absorber or with the atmospheric
air. The valves 38 and 43 are operated by an iron core 41 set within the
solenoid 40, 41, the said valves being directly connected with the said core in such
a manner that when the circuit is completed by the thermometer the iron core
together with the valves 38 and 43 rises whereby the valve 43 is closed while 38 is
opened. Owing to this arrangement and to the connection established by 42
between A and E the piston 8 is caused to move inwardly in E whereby the
operating mechanism of the pump and consequently the pump itself are set in
operation.
The pump then remains in operation until the normal temperature is again
attained and consequently the circuit broken again by the thermometer.
Figure 11 represents the valve K so arranged that the iron core 41 together
with the solenoid 40 is situated between 38 and 43 and that a direct connection is
not established between these three parts so that the opening of the valve is
produced by the rising and falling of the iron core while the closing thereof takes
place under the action of special springs. These springs however may be omitted
if preferred in which case the iron core should be connected with the valves in a
manner similar to that illustrated in Fig. 10.
Instead of inserting K into the circuit controlled by the thermometer the
solenoid of the apparatus E represented in Fig. 4 may be directly connected to that
circuit.
This switch apparatus for air or vacuum pumps influenced both by the
prevailing temperature and the vacuum may also be made serviceable for cooling-
plants comprising a series of cooling-chambers for the purpose of automatically
closing one or more of such chambers as soon as a predetermined temperature has
been attained in them so that it only remains for the cooling machine to perform
its action in those cooling-chambers in which the temperature is higher than is
required.
As clearly stated in the foregoing description the connection of an ordinary
single cylinder vacuum pump working with oil with the devices and apparatus
above described is so far improved that even if the cooling-plant be not operated
regularly but only partially and at unequal periods of time, a uniform and
sufficiently complete vacuum may automatically be obtained practically at a
moment's notice and maintained as long as necessary.
The concentrator F represented in Figures 1A, 1B, and 1° adapted to concentrate
the absorbing liquid supplied from the absorber consists with a view to the better
utilization of the fuel of a reservoir 35, a distribution-ring 30, a corrugated
tube 31, a boiling pan 32, a furnace 33, and a casing 34 which, to increase the
useful effect of the arrangement, may also be made in the form of a corrugated pipe
so that it can be heated. By means of the valves 29 the discharge of the liquid
is regulated in such a manner that through the medium of the distribution ring 30 as
much of the liquid flows down the heated pipe 31 (also serving as a Hue or
chimney) into 32, as is necessary to keep up concentration, so that the concentrated
liquid may constantly be running off into B. The steam produced by the boiling
process and the products of combustion passing through 31, before they are led off
to the chimney serve to heat the liquid in the reservoir 35 so that it enters 32
after having undergone a preliminary heating.

page_text: | Having now particularly described and ascertained the nature of the said inven-
on, as communicated to me by my foreign correspondent, and in what manner
e same is to be performed, I declare that what I claim is,-
1. A vacuum cold producing machine in which a constant nearly complete
acuum is automatically produced and maintained in the absorber and a
redetermined uniform temperature produced and maintained in the cooling
hamber however unequal and irregular may be the operation or employment of
e cooling arrangement while at the same time a better utilization of the fuel in
he operation of the concentrator is ensured the arrangement being such that
ccording to the less or more complete rarefaction of the air in the absorber and
the higher or lower temperature prevailing in the chamber or the liquid to be
poled a single vacuum or air-pump (Fig. 2) provided with an oil-interceptor is
utomatically set in and out of operation by means of a regulating device (Figs. 3
11) while at the same time either by the same regulating device or by any
ther suitable arrangement (Fig. 2A) the air-pump (i.e. its cut-off cock or equivalent)
automatically closed when the operation is discontinued and opened when it is
arted again the fuel being moreover more fully used by an improved form of
oncentrator.
with
2. In combination with the cold producing machine characterized in the first
aim and for the purpose indicated in that claim the arrangement of
(a) A vacuum or air-pump consisting of a single cylinder (Fig. 2) for
producing a partial or nearly complete vacuum the pump being of ordinary
construction and having its joints tightly closed by means of oil of a
reservoir 3 for the reception of superfluous oil and of a nozzle 4 reaching
to the lowest point of the reservoir having notches 5 provided at its lower
end and the cup-shaped valve 6 movable at the lower end of this nozzle for
the automatic discharge of the oil oozing into the reservoir in combination
(b) a regulator such as E Figs. 3 to 9 enabling the air or vacuum-pump as
characterized in the preceding paragraph to be automatically set in and out
of operation according to the lower or higher rarefaction of the air the
said regulator consisting of a cylinder 7 in which works a piston 8 one side
of which is constantly connected with atmospheric air and the other side
through the medium of an oil-cataract 9 communicating with the absorber
while either one or the other or both sides of the piston are provided with
mechanism for throwing the pump into or out of gear; or in combination
with a modification of E such as is shown in Fig. 4 in which the fluctuations
of the rarefaction of air in the absorber act upon a diaphragm through the
movement of which an electrical circuit comprising a solenoid is opened
or closed so that through the motion of an iron core such as 8 the motor
engine of the air-pump is thrown into or out of operation; or lastly with a
modification of E such as is shown in Figures 5 to 9 in which the oil-
cataract is connected with an arrangement consisting of a case 17 and a
diaphragm 18 one side of which is connected with an absorber while the
other carries a valve 30 having for its seat another valve 21 which closes
the channel 26 27 so that the space or chamber 39 closed by the
membrane 22 and connected with the oil cataract also communicates with
the atmosphere through the valve 20 and port 28 whenever the air is
sufficiently rarefied in the absorber while if not after the valve 21 bas
been opened and the valve 20 closed a communication is established with
the absorber so that the piston 8 causes the pump to be thrown into
operation; or for the purpose of throwing the pump into or out of gear
according as the temperature in the chamber containing the liquid to be
cooled is higher or lower; the combination of the regulator E with the
slide-valve K operated by electricity (Figures 10 and 11) consisting of a
three-way valve-chest 36, the valves 38 and 43 which are operated by the

page_text: iron core 41 working within the solenoid 40 in such a manner that a
connection is alternately established with the absorber and channel 37 or
between the said channel and the atmosphere it being immaterial whether
the solenoid is situated under, over, or between the valves.
(c) For the purpose of maintaining the vacuum (so far as that is influenced
by escape or leakage through default of tightness of the pump) during
interruptions in the operation (the pump being at the same time auto-
matically set in and out of gear) and for the purpose of causing it
automatically to enter into connection with the absorber or to cut off such
connection by joining the cut-off cock or equivalent 54 to the piston or
piston-rod of E the cut-off device represented in Figure 2 characterized
by the cam 45 connected with the motor-shaft adapted to operate a
sleeve 47 movable along its surface but not revolvable and through it the
lever or link arrangement controlling the cut-off cock and consequently the
cock itself in such a manner that when the pump is set in operation
the motor completes one idle revolution in doing which it energises a
spring 51 connected by its outer and inner ends respectively to the motor
shaft and screw shaft 53 and displaces the sleeve to the distance of the pitch
of the screw-thread the consequence being that the cut-off cock or equivalent
opens after which the arms 49 50 impart rotary motion to the screw spindle 53
while the closing of the cut-off cock is provided for by such an arrangement
that when the motor is arrested or thrown out of gear the motor shaft and
the cam or screw thread connected with it under the re-action of the spring 51
rotate in the opposite direction whereby the sleeve under the action of the
spring 52 is also caused to make a movement in the opposite direction and
return to its former position carrying with it the lever 44 and closing the
cock.
d) For the purpose of putting the fuel to better advantage the arrangement
of a concentrator (Figs. 14 1B and 1°) adapted to receive the liquid coming
from the absorber A consisting of a heating reservoir such as 35 the
distributor pipe or trough such as 30 pipe or flue 31 evaporating pan such
as 32 heating-apparatus or furnace 33 and casing or jacket 34 so arranged
that the steam developing in 32 before it can escape through the chimney
serves conjointly with the gases or products of combustion passing through
the flue for heating the liquid contained in 35.
Dated this 13th day of March 1893.
W. P. THOMPSON & BOULT,
Agents for the Applicant.