US2195228A

US2195228A - Refrigerating apparatus and process

Info

Publication number: US2195228A
Application number: US130759A
Authority: US
Inventors: Schwarz August
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-03-13
Filing date: 1937-03-13
Publication date: 1940-03-26
Anticipated expiration: 1957-03-26

Description

March 26, 1940. scHw z 2,195,228

REFRIGERATING APPARATUS AND PROCESS Original Filed May '7, 1934 3 Sheets-Sheet l Imfenm March 26, 1940. A, SCHWARZ 2,195,228

REFRIG ERATING APPARATUS AND PROCESS Original Filed May 7, 1934 3 Sheets-Sheet 2 lmfen'tan March 26, 1940, A SCHWARZ 7 2,195,228.

REFRIGERATING APPARATUS AND PROCESS Original Filed May 7, 1934 3 Sheets-Sheet 3 I I I'm/canto. Tues-$9.3 7 a? I v I W I M Patented Mar. 26, 1940 UNITED ,sT'ATEs REFRIGERATIN G APPARATUS AND PROCESS August Schwarz. Chicago, Ill. Reiiled for abandoned application Serial No.

724,335, May 7, 1934.

This application March 13, 1937, Serial No. 130.759

34 Claims.

My invention has for its object the provision of apparatus adapted for low temperature and quick freezing refrigeration; also for condensing the final refrigerant by low temperature and by low condenser pressure; including means whereby the low temperature and low pressure liquid may be boosted and further cooled under high pressure.

The invention involves what may be termed two single stage systems, namely apparatus so associated, but selectively operable, that a portion may be operatively disconnected from the other portion and each portion employed'as a single phase system, one single phase system involving a compressor, a condenser, a pre-cooler, expansion means and evaporator means; while the other single phase system involves a compressor, a condenser, liquid pump, a pre-cooler, expansion means and evaporator element, together with means whereby the liquid pump, may, at the will of the operator, be operatively eliminated.

The invention also involves valve controlled means whereby the pre-coolers, either one or both, in both of said systems may be eliminated when desired.

The invention also involves a two stage condensing and refrigerating system whereby the carbon-dioxide refrigerant is condensed and cooled in two stages; the first stage including a low temperature and low pressure condenser cooled by the expansion'of a volatile refrigerant; further whereby the pressure of the low temperature and low pressure carbon dioxide from said condenser may be boosted and the carbon dioxide further cooled under high pressure; and also means whereby a portion of the first mentioned liquid refrigerant commingled with a portion of the boosted and further cooled liquid carbon dioxide refrigerant before expansion, and further means whereby a portion of the low temperature and high pressure liquid carbon dioxide refrigerant may be utilized for making dry ice in con-' nection with dry ice making apparatus.

The invention also involves means whereby high pressure and low temperature liquid is available for the same purpose; and means whereby low temperature and low pressure liquid is available for the purpose of'further cooling the liquid in the ice making apparatus; with arrangements whereby the exhaust may be drawn off from the ice-making or cooling apparatus and arrangeinents whereby the spent carbon dioxide for icemaking or cooling may be conveyed into my improved apparatus; my improved apparatus for with the discharge gas of said condensing and cooling under low and high pressure permitting use of the system as a single or a double stage refrigerating system.

My invention also involves a single unit which permits compressing and condensing a refriger- 5. ant; pre-cooling an oncoming liquid refrigerant in heat exchange relation with the vaporized refrigerant; the unit providing a path for a fluid medium to be heated or cooled therein, expansion means and evaporating elements in said unit.

My invention further involves an evaporator consisting of a vertically arranged shell divided by a wall in an upper and lower compartment, the lower compartment being provided with evaporating elements, the ends of said elements 5 extending through said wall and communicating with said upper compartment, and a fluid conveying element, said lower compartment being also provided with a plurality of inlet conduits and outlet conduits, whereby a fiuid cooled in said compartment may be introduced into said compartment at different levels and withdrawn therefrom at different levels, said upper compartment being provided with a liquid receiving and cooling element and in heat exchange relation evaporating element.

My invention still further involves a refrigerating apparatus adapted either as a condenser or as an evaporator, said apparatus comprising a vertically arranged shell defining a chamber provided with a condenser element, an evaporating element and a liquid cooling element, the outlet end of said cooling'element being connected with the inlet of said evaporating element, the shell '35 being;al'so provided with an inlet and anoutlet conduit, whereby a fluid medium to be heated or cooled may be passed through the chamber of said shell in heat exchange relation with all of said elements. I 40 This application covers new inventions which also represent novel improvements over the in ventions of my Patent No. 1,951,447Qrelssue application for which is now being prosecuted, and also represents a refiling of my abandoned application, Ser. No. 724,335, filed May 7, 1934.

The accompanying drawings more or less schematically illustrate what I believe to be the best embodiments of my invention, although many variations and modifications of the sys- 5o tems are possible, and numerous arrangements of the relative positions may be made without departing in any way from my invention.

Fig. 1 isv a vertical sectional view of my improved system, arportion of one of the units being broken away, while other portions are diagrammatically illustrated.

Fig. 2 is a detail sectional view taken substantially on the line 2-2 of Fig. i, as viewed by the arrows.

Fig. 3 is a vertical sectional view of a modification of my improved system; certain portions being shown in section while other portions are diagrammatically illustrated.

Fig. 4 is a vertical sectional view of another modification of my improved system, with certain portions shown diagrammatically.

. duit In the particular embodiment of the invention as shown in Figs. 1 and-2, a compressor is indicated at I, connected by means of conduit H with a condenser l2, which may be water cooled or cooled by any other suitable medium; the medium may be introduced through inlet l3 and withdrawn by outlet l4.

In the illustration, the condenser is shown provided with headers l5 and ii at opposite ends which are connected by a suitable number of tubes or coils as at H.

The condensed refrigerant is conveyed from the outlet header l6 of the condenser by means of conduit l8.

In-this particular embodiment of the invention, the conduit I8 is shown connected with a liquid receiver or liquid cooling element l9 which extends into or is located in a combined condenser, evaporator and liquid cooler unit 29, and preferably adjacent the discharge end of the evaporator element or elements 2| in said unit 20.

The flow of the liquid through the cooling element I9 is controlled by a suitable number of valves as at 22 and 23, 23. It is apparent from the arrangement shown that when valve 22 is closed and

valves

23, 23 are open, the refrigerant or liquid in conduit |8uwill be made toflow through element I9 and then returned to con- 24. The liquid or refrigerant is conveyed by conduit 24 to the inlet end of unit 20 where the conduit is provided with an expansion valve 25. The liquid or refrigerant is evaporated or expanded into the header 26 of unit" and allowed to evaporate in tubes 2| by which it is conveyed to header 21, whence it is withdrawn by conduit 28 connected with the suction end of compressor l0, where the gas is recompressed and returned to condenser unit l2; said elements forming aprimary refrigeration cycle.

The chamber in unit 20, intermediate of the

headers

26 and 21, is provided wi valve controlled inlet 29 and valve controlled outlet 39, whereby any suitable liquid cooling medium may be circulated through the unit 29 in heat exchange relation with the evaporatorelements 2|.

A secondary or low temperature refrigeration cycle involves a compressor 3| provided with con- 1 duit 32 which conveys the compressed refrigerant to a condenser element or elements 33 arranged in unit 20 intermediate the headers In the particular embodiment of my invention, I show the coils disposed intermediate the different rows of evaporating elements or tubes 2|, as more clearly shown in Fig. 2. With this arrangement, the conduit 32 discharges the compressed refrigerant into a header or manifold 34 which connects with the inlet ends of all of the condenser coils 33, as shownin Fig. 2; while the discharge or outlet ends of these coils are connected with a similar header or manifold 35.

The condensed and low temperature liquid 51. It is apparent that when valve 51 26 and 21.

condenser elements in the nature of refrigerant coming from the condenser header 35 is conveyed by conduit 36 to a conduit 31 whereby the low temperature liquid refrigerant is conveyed into a liquid receiver or cooling element 38, shown in the nature of coils arranged preferably at the discharge end of an evaporator unit .39.

The unit 39 is preferably shown provided with headers 40 and 4| at opposite ends; and these headers are connected by means of a plurality of tubes or coils 42.

The low temperature liquid refrigerant is conveyed by element 38, into conduit 43 which is provided with a pipe connection 44 provided with expansion 'valve 45, whereby the refrigerant is expanded and vaporized into header 40, passing through tubes or coils 42 into discharge header 4|, from whence the vaporized refrigerant is withdrawn by conduit 43 which connects with the suction side of compressor 3|, where the refrigerant gas is recompressed and returned to condenser 33.

The chamber of unit 39 is shown provided with a valve controlled inlet 41 and a valve controlled outlet 48,.whereby a suitable liquid cooling medium may be circulated through unit 39 and conveyed to any desirable place of use; the medium being made. to flow in heat exchange relation with the tubes or coils in evaporator 39 and the liquid receiver or cooling element 38.

A conduit connection 49 is disposed intermediate of conduit 31 and pipe 44; and this connection 49 is shown provided with valves 50 and 5|; while conduit 31 is shown provided with a valve 52 and conduit 43 is shown provided with a valve 53 adjacent to pipe 44.

It is apparent that when valve 52 and valve 53 are closed and valves 50, and 5| are opened, the liquid refrigerant coming from conduit 35 will be made to flow into pipe connection 49 and conveyed to pipe 44 and expanded into header 40 of unit 39.

Interposed between conduit 36 and pipe connection 49 is a by-pass line 54 provided with a liquid refrigerant pump 55. The by-pass 54, on opposite sides of pump 55 is shown provided with

valves

56, 56, which must both be open when pump 55. is in use.

Conduit 36, at a point intermediate by-pass 54 and conduit 31, is shown provided with a valve and valve 5| are closed, with

valves

56, 55, 50, 52 and 53 open, the liquid refrigerant will be boosted by pump 55 and made to flow through conduits 54, 49, 31, cooling element 39, conduit 43 into pipe 44 and expanded through expansion valve 45.

On the other hand if the liquid refrigerant is not to be further cooled by element 38, valves 51 and 50 and 53 are closed, while valves 56, 53, 5| and expansion valve 45 are opened, thus causing the boosted liquid refrigerant to be discharged by pump 55 into by-pass 54 and into connections 49 and 44 and through expansion valve 45.

In Fig. 3 I show a modification of the system wherein the apparatus may be used as a double stage refrigeration system; or the apparatus may be used for condensing and cooling purposes of carbon dioxide gas or other refrigerants, under low and high pressures.

The apparatus of this modified system involves the compressor H) which is connected by conduit II with a header |5 at one end of the condenser I2 which condenser may be cooled by any suitable liquid cooling medium introduced through inlet I3 and withdrawn through outlet I4. The condenser I2 may be horizontally disposed.

The condenser I2 of Fig. 3, like the condenser shown in Fig. 1, is preferably provided at opposite ends with headers or manifolds which are connected to each other by suitable numbers of tubes or coils as indicated at I! arranged in slightly spaced relation and disposed through the chamber within the condenser housing through which any suitable .cooling medium may be circulated as heretofore stated.

The header l6 receives the condensed refrigerant from coils or pipes I1 and discharges same into conduit I6. The conduit l6, like in the previously described construction, is shown connected with a liquid receiver or liquid cooler element I9 which extends into and is located in the combined condenser, evaporator and liquid cooler unit 26 and preferably adjacent the discharge end of the refrigerator element or elements 2|. The flow of the liquid through the cooling element I9 is controlled by the

valves

22 and 23, 23. With,

this arrangement, when valve 22 is closed the liquid refrigerant from conduit [6' will be made to flow through the element l9 and then returned to the conduit 24 by which it is conveyed to expansion valve 25 arranged at the inlet end or header of the unit 26*. The liquid or refrigerant is evaporated or expanded into the header 26" and arranged to evaporate in tubes 2 I a by which it is conveyed to header 2'I from whence it is withdrawn by a conduit 26" which is connected with the suction side of compressor III where the gas These elements, like in the previously described apparatus, constitute a primary refrigeration cycle.

The chamber in the unit 26 at points intermediate of the headers or

manifolds

26 and 21*, is provided with valve controlled inlet 26 and valve controlled outlet 30' whereby any suitable medium may be circulated through the unit 20 in heat exchange relation with the evaporating elements 2| and the cooling element I9 as well as the condensing element now to be referred to,

A secondary or low temperature refrigeration cycle, provided by my improved apparatus, involves a compressor 3I= provided with conduit 32 which conveys the compressed refrigerant to a condenser element or elements 33* located in unit 26'. The unit 20 is substantially similar to the construction shown in Fig. 2 with a plurality of condenser coils 3'3 whose inlet ends communicate with the manifold or header 34 while the outlets ends of said coils are connected with manifold -or header 35 which latter is connected with a conduit 56 which, in turn, connects with a liquid refrigerant pump 56 whose discharge end in turn is connected with conduit 66. Conduit 60 is shown connected with a manifold or header 6| of a series of liquid cooling tubes or coils 62 disposed throughout the length of a cooler and evaporator unit 63. The outlet ends of the liquid tubes or coils 62 are shown connected with a suitable manifold or header 64. The manifold or header 64 is shown provided with a valve controlled discharge conduit 65 whereby the cooled medium, for example carbon dioxide, coming from cooling coils 62, may be conveyed to distant points or to dry ice or solid carbon dioxide making apparatus. Conduit 65, intermediate the header or manifold 64 and the valve 66, is connected with a conduit 67 having a valve 66, and conduit 61 in turn is is rec'ompress'ed and returned to condenser unit connected with pipe 66 provided with expansion valve I6 connected with the inlet header or manifold II at one end of unit 63. The expanded liquid is evaporated through tubes or coils I2 which extend from header II to the header I3 at the opposite end of the unit.

The header or manifold I3 is provided with a conduit II which connects with the suction side of compressor 3i.

- The discharge end of liquid pump 59 is also con nected with a pipe line I5 which connects with pipe I6, one end of which communicates with the connection of pipes 61 and 69, thus permitting liquid to flow, under high pressure through pipes I5 and I6 and be commingled with the still lower temperature liquid coming through pipe 61 from the condenser coils 62 before passing through expansion valve I0. Conduit 56, in advance of its connection with pump 59, is shown provided with a by-pass conduit 11 which connects with the juncture between pipes I5 and I6. 'A portion of said liquid under relatively low pressure is conveyed through coils or tubes .62 while the other 'portion may be.conveyed to the expansion valve I6 and the evaporated gas withdrawn as heretofore mentioned; while the low temperature and low pressure liquid coming from coils or tubes 62 may be discharged through conduit 65 and valve 66 (if the latter is open) for the purpose as heretofore mentioned.

In order to induce the liquid to flow in the manner as heretofore described, conduit 56, in advance of pump 59, is shown provided with a valve I6; by-pass I1 is provided with a valve I9; while conduit I5 is shown provided with a valve 66 and conduit 66 provided with a valve 6| and conduit I6 with a-valve 62. It is apparent that when it is desired toemploy the liquid pump59, valve I6 must'be open, valve I9 closed while valves 66 and 6| are open, as well as valves 62, and 68, thus causing a portion of the liquid to flow through conduit 60 into cooling coil 62 while another portion of the liquid will flow directly through pipe I5 into pipe I6 and be com-- mingled with the pre-cooled liquid from coil 62 coming through conduit 61 and the pre-cooled liquid expanded through valve I'll into unit 63.

With the arrangement just described, a portion of the liquid coming through by-pass 11 may be conveyed by connection I5 into conduit 66 and caused to pass through coils 62, while a portion of said liquid may be conveyed by connections I6 and 61 to discharge conduit 65 where the liquids of different temperatures are commingled and conveyed to the desired point of use.

Upon closing valves 60 and 66 with valves I6, I9, 62, and 6] open, a portion of the liquid coming from the manifold 35* will flow under low pressure through by-pass II, conduit I6 and pipe 69 into expansion valve I6 and be expanded into unit 63 from whence it is withdrawn through conduit I4 by compressor 3|; while another portion of the liquid coming from pump 59 passes through conduit 60 into the cooling coil 62 and is conveyed through pipe and valve 66 for purposes as heretofore mentioned.

The by-pass II is shown connected to a pipe 63 with a valve 64 whereby low temperature liquid under low pressure may be drawn oil for use, for example, in dry ice making apparatus for refrigerating or freezing the high pressure low temperature liquid refrigerant coming from conduit 65. The gas, which is evaporated in the dry ice making machinery may be returned to my apparatus conduit 14. A new supply of gases for replenishing the refrigerant supply may be introduced by means of valve 81 arranged in a coupling or connection 83 on the suction side of compressor 3|.

The unit 53 at opposite ends, like unit 39, is shown provided with a valve inlet 41 and a valve controlled outlet 40, this inlet and outlet communicating with the chamber of the unit 63 to permit the introduction of any suitable medium, such as brine and the like, to be used as a heat exchange medium for the tubes or coils 52, because the medium introduced through inlet 41' would surround the evaporation tubes 12 and the tubes or coils 52.

It is apparent that upon merely closing valves 68, 8 I, that unit, 63 may then be transformed into a refrigerating unit of a single stage or double stage system; and brine or any suitable medium may be circulated through the refrigerating unit in contact with the evaporator tubes.

In Fig. 4 I illustrate a still further modification of my improved apparatus and method of operation, wherein 89 is a combination gas cooler and condenser unit for difierent refrigerants; the unit being provided at opposite ends with suitable manifolds or headers as at and 9| connected with each other by a suitable number of coils or pipes 92. The gas is compressed by compressor I0 and introduced into header or manifold 90 by conduit 93 and into the tubes or coils 92 before being discharged into header 9I from whence the condensed liquid refrigerant is taken by conduit 94 which leads to a pre-cooler arranged in the header 96 of a unit 91. The opposite end of pre-cooler 95 is connected with a conduit 98 which leads to an expansion valve 99 arranged at the inlet of header I00 at the opposite end of unit 91. The gas is evaporated through tubes or coils IGI in unit 91, conveyed into header 96 and taken off by conduit I02 which leads to the suction side of compressor I0". The apparatus thus far described constitutes one cycle of operation.

A second closed refrigeration cycle involves compressor 3I which is provided with discharge conduit I03 whereby the compressed gas refrigerant is conveyed to a header or manifold I04 arranged at the inlet ends of the cooling tubes or coils I05 arranged in the combination gas cooler and condenser unit 89. The pre-cooled gas from the cooling coils I05 is discharged into a header or manifold I06 and thence into conduit I05 which is provided with valves I08 and I09.

The conduit I01, at a point intermediate of valves I08 and I09, is provided with a branch IIO which leads to a header or manifold III arranged at the inlet ends of the low temperature condenser tubes or coils II2 which are arranged in unit 91 disposed intermediate of the various sets of evaporating tubes IOI in said unit; the condenser coils II2 being arranged in the chamber of the unit 91 intermediate of the headers at opposite ends. The outlet ends of the condenser coils II2 are shown connected to a header or manifold II3 connected to a conduit II4 which leads to a liquid refrigerant pump H5 which, in turn, is provided with a.discharge conduit IIG leading to a pre-cooler element II1 arranged in the header II9 of evaporator unit 9. The precooler element II1 has its opposite end connected with a conduit I20 which leads to conduit I2I provided with expansion valve I22 arranged at the inlet end of header or manifold I23 of unit H9. The liquid gas discharging into header I23 is evaporated through the tubes or coils I24 arranged intermediate the two headers I23 and H3. The evaporated gas from header II! is taken by conduit I25 to the suction side of compressor 3|. The evaporator unit H9 is provided with a plurality of tubes or coils I26 which are arranged intermediate the various sets of evaporator tubes I24 in unit II9; the inlet ends of the coils being shown provided with header or manifold I21 which is shown connected with a valve controlled inlet conduit I23; .while the outlet ends of the coils I26 are shown connected with a manifold or header I29 which likewise is connected with a valve controlled outlet I30.

Any suitable medium to be condensed or liquid to be cooled is introduced through conduit I23 into manifold I21 and through the coils or tubes I25 from whence it is discharged into manifold or header I29 and take-off conduit I30 to any desired place of use.

The chamber of the unit H9, at spaced apart points throughout its length, is shown provided with valve controlled inlet I3I and a valve controlled outlet I32 whereby any suitable medium to be cooled, such as brine and the like, may be introduced into the chamber portion in heat exchange relation with theevaporator tubes and taken off by valve controlled conduit I32. At points intermediate the valve controlled inlet and outlet, the unit I I9 is shown provided with valve controlled connections I33 and I34 whereby-the medium, for example, brine, introduced through valve controlled inlet I3I, may selectively be withdrawn from the chamber of unit H9 at various points, as for example either at outlet I33, I34 or I32, and brine, or any other fluid, of different temperatures, maybe available depending upon the use to which the same is to be put. The unit I I9 is also shown provided with a valve controlled inlet I35 preferably arranged closer to the coldest end of unit II9 than inlet I3I. The inlet I35 is for the purpose of introducing brine from a point of use, but which is of a lower temperature than the brine entering through conduit I3I so as not to come into immediate contact with the discharge ends of the evaporator tubes or coils I24 and with the brine coming in through valved inlet I3I, or to immediately mingle with the brine of higher temperature entering through inlet I3I.

The pre-coolers 95 and H1, as shown and described, are both arranged in the discharge headers or units 91 and H9 respectively, where they are merely in heat exchange relation with the discharging evaporated gas and not in heat exchange relation with the cooling mediums in the chambers of said units and with the coils therein.

The unit 91 at opposite ends is shown provided with a valve controlled inlet I35 and a valve controlled outlet I31 for the purpose of introducing a suitable medium into the chamber of the unit, such as brine and the like, which may ,either act as a heat transfer medium; or the medium may be used as a cooling medium for the condenser elements II2, if said unit is merely employed as a condenser in a single stage system; or may be circulated therethrough for outside uses. In this instance, if brine is lead through unit 91, it will constitute a combined evaporator, low temperature condenser and cooler unit.

The chamber of unit 89, at opposite ends, is also shown provided with a valve controlled inlet I33 and a valve controlled outlet I39 whereby any suitable cooling medium may be introduced into the chamber of unit 89 in contact with the condenser tubes and gas cooling tubes or coils.

The liquid cooling element 95 is shown provided with valves I48, I for disconnecting the cooler 95; while conduit 98, intermediate the ends of the pre-cooler coil 95, is shown provided with a valve I4I.

With this arrangement, it is apparent that with valves I40, I40, open and valve I4I closed, the liquid refrigerant from conduit 94 will be made to pass through the pre-cooler 95 before being discharged into conduit 98. On'the other hand, with valves I40, I40 closed and valve I open, the liquid refrigerant from conduit 94 will be made to pass directly into conduit 98 and be delivered to expansion valve '99.

The gas cooler in unit 89 may be disconnected from the system by closing valve I42 and closing valve I08 at the outlet header I08; while with valves I43 and I09 in conduit I01 open and a valve I44 in branch pipe IIO open, the compressed gas coming from compressor 3l will be caused to flow through conduit I03, conduit I01 and be delivered into header III, into coil or tubes II2 where it is condensed and the liquid made to flow as heretofore described.

Conduit I 01, at a point intermediate valves I09 and I43, is shown provided with a branch conduit I45 which is shown connected with conduit H4 and also with conduit I20; the branch conduit I45, in advance of its connection with conduit II4, having a suitable valve I46 and at a point intermediate the connection of conduits I I4 and I20 provided with a valve I41. With this arrangement the coil or coils I05 in unit 89 may.

then function as a condenser and the liquid refrigerant then conveyed from discharge header I06 by conduit I 01 to branch conduit I45 which connects with conduit I2I leading to expansion valve I22 of unit II9.

In order to induce this flow, valve I44 is closed, valve I09 opened and valve I43 closed; a valve I48 in branch conduit I45 opened, as are also valves I48 and I41; while a valve I49 in conduit H4 and a valve I50 in'conduit I 20 are closed. The condensed liquid refrigerant is expanded into header I23 of unit H9 and taken from the outlet header II8 by conduit I25 connected with the suction or low pressure side of compressor 3I the re-compressed refrigerant or gas being then conveyed by conduit I03 into header I04 connected with the coils or tubes I05 of unit 89.

Conduits H4 and I20 are shown connected by a branch pipe I 5I provided with a valve I52; said connection being adjacent 4 to the discharge header or manifold 8 of condenser coils H2 and unit 91; and the connection between the manifold or header H3 and conduit H4 is also shown provided with a valve I53. With this arrangement, the liquid refrigerant coming from c il or coils I05 in unit 89 will be'conveyed from discharge header I08 by conduit I01 (assuming that valve I44is closed) into branch pipe I45 and by closing valves I41, I52 and I53, the liquid refrigerant is made to flow upwardly, through conduit II 4 to pump II5 into conduit II8 which connects with pre-cooler element II1.

The inlet and outlet ends of pre-cooler II1 are provided with valves I54, I54 so that the precooler unit II1 maybe disconnected from the s stem by closing said valves and opening a valv I55 in conduit I20.

If the pre-cooler element H1 is not desired, the boosted refrigerant from pump II5 coming through conduit II8 will be made to flow down through conduit I20 which connects with conduit I2I leading to expansion valve I22 and the refrigerant expanded into header I23 of unit 'a valve I58, while the by-pass is shown provided with a valve I59. With this arrangement, valves I51 and I58 may be closed and valve I59 opened,

thus eliminating the pressure pump H5 and allowing the liquid coming from conduit II4 to flow through by-pass I59into conduit II8 which connects with pre-cooler II1, and'the pre-cooled liquid refrigerant to be conveyed by conduit I20 to conduit I2l which connects with expansion valve I22, allowing the liquid refrigerant to evaporate through the tubes or coils of unit H9 and be withdrawn therefrom by conduit I25 connected with the suction or low'pressure side of compressor 3|".

The cycle that has just been described constitutes a single stage system which comprises a compressor, a condenser, a liquid refrigerant pump, a pre-cooler, an expansion valve and evaporator element, all arranged-substantially in the order named,*the system also involving a by-pass whereby the liquid pump maybe eliminated, together with arrangements whereby the pre-cooler may be eliminated, this single stage system as just defined involving elements I 05, unit 89 and unit I I9 with compressor 3|.

A second single stage system, independent of the other mentioned system, is provided with my improved apparatus and involves compressor I0", condenser tubes or coils 92 of unit 89, pre-cooler '95, expansion valve 99 and evaporator tubes IOI of unit 91 with the'discharge conduit I02 connected with the suction or low pressure side of compressor I0 The liquid to be cooled in unit 91 may be introduced into the chamber thereof through valve controlled inlet I36 and may be withdrawn therefrom through valve controlled outlet I31. In the case just mentioned,- the tubes or coils IOI act as evaporator tubes and unit 91 therefore acts as a refrigerator only. The precooler element 95 maybe eliminated as heretofore described.

It will be noted that these two single stage systems just described work independently of each other and may work with diflerent refrigerants; and that unit- 89 acts as a double condenser for the different refrigerants of both systems. This condenser may be cooled by fresh water or anv other suitable medium-- The apparatus shown also provides another single stage system which involves compressor 3I coils or tubes, constituting condenser tubes in this instance, arranged in unit 91, pre-cooler II1, expansion valve I22 and evaporator tubes in unit N9: the discharge ends of evaporator tubes in unit II9 having communication with the suction or low pressure side of compressor 3I by conduit I25; the compressed refrigerant being conveyed by conduit I03 into the header II I of condenser coils or tubes I I2. In order to provide this path for the refrigerant, valves I42, I48, I08, I49, I52, I59, I55 and I41 are closed; while valves 3,109, I44, I53, I51, I58, both valves I54 and I50are open.

The condenser tubes or coils H2 in unit 91 may be cooled by any suitable medium introduced through valve controlled inlet I36 and the medium withdrawn from the chamber of unit 91 by means of valve controlled outlet I 31. Where it is desired not to further boost the pressure of the liquid refrigerant, pump I I5 may be eliminated through the closure of valves I51 and I58 and opening valve I59 in by-pass I56.

At the same time, pre-cooler II1 may be eliminated in this circuit by closing valves I54, I54

and opening valve I55, thus causing the boosted" refrigerant to pass directly into conduit I from conduit II6.

Furthermore, the pressure pump H5 and the pre-cooler II1 may both be eliminated from this system so that the discharging liquid refrigerant coming from header II3 may be made to flow directly toward expansion valve I22 by closing valves I49, I51, I59, I50 and I41; while valves I53 and I5l are open.

This causes the liquid refrigerant to flow directly from the discharge header I I3 into conduit I20 leading to conduit HI and to expansion valve I22.

The single stage system just described provides a low pressure or normal phase and a high pressure phase, because the liquid is condensed under normal pressure in coils H2 and the oncoming boosted liquid then further cooled before expansion by the expanding gas in unit I I9.

The refrigeration system or cycle just described does not include unit 89. On the other hand, unit 91 may be entirely disconnected from the system, and one set of tubes or coils in unit 89 used as a condenser in connection with the evaporator elements of unit II9 and compressor 9|"; this circuit involving compressor 9| conduit I03, header I04, coil or coils I05, discharge header I05, conduit I01, branch pipe I45 and expansion valve I22 of the evaporator unit II9. In this instance, of course, valves I43, I44, I49 and I50 are closed. Should it be desired to further boost and precool the liquid refrigerant, valves I53, I59, I55

and I52 are closed, while valves I42, I08, I09, I48,

I45, I49, I51, I58, I54 and I50 are open.

If it is desired to pre-cool and not to "boost" the liquid refrigerant, then valves I51 and I58 are closed and valve I59 opened allowing the liquid refrigerant to by-pass the pump.

0n the other hand, if it is desired to boos the pressure and not to pre-cool this liquid, then valve I59 and valves I54, I54 are closed and valve I55 opened, causing the "boosted" liquid refrigerant to be discharged into conduit I20, I2I connected with expansion valve I22.

Another single stage system is provided which may eliminate the use of unit II9; this system involving compressor I0", tubes or coils 92 oi unit 09, discharge 94, pre-cooler 95, conduit 98, expansion valve 99, evaporator tubes or coils I0i and discharge conduit I02, connected with the suction or lower pressure side of compressor I0". The medium to be cooled may be conveyed into the chamber of unit 91 through valve controlled inlet I35 and discharged through valve controlled outlet I31. In order to provide this circuit for the refrigerant, it is apparent that valve I is closed,

while valves I40, I40 are open with expansion valve 99 being also open. If the pre-cooler 95 is to. be eliminated, then valves I40, I40 are closed Elli valve I44 opened.

When the entire system is in operation, difierent refrigerants may be employed, as for example ammonia, or similar refrigerants condensing under relatively low condenser pressure, employed in the first or primary cycle, and carbon dioxide, or similar refrigerants of low boiling point condensing under relatively high pressure under normal temperature, may be employed in the second or low temperature cycle; or ammonia or similar refrigerants may be employed in both cycles, depending upon the work to be accomplished or conditions under which the system is being operated; as set forth in my previously filed applications.

It is understood that if the entire system is in operation the high boiling point refrigerant is condensed in tubes 92 of unit 89 and expanded in tubes IOI of unit 91; while the low boiling point gas refrigerant may first be cooled in coils I05 of unit 99, further cooled in coils II2 of unit 91 and evaporated in thetubes of unit II9. The initial gas cooler I05 may be disconnected from this circuit so that the low temperature exhaust from unit II9 may be directly conveyed into coil H2 of unit 91.

It is to be understood that I do not limit myself to the use of a volatile refrigerant, but any other refrigerant may be used including one which condenses under atmospheric pressure and temperature, especially where the apparatus is intended to be used as a single phase system and in smaller units. 1 l

While I have shown and described my invention and the arrangements of elements in the separate units, I do not wish to limit myself to the arrangements as shown. If the separate systems are, however, constructed and operated and no brine or other fluids are passed through the chambers of units 20, 20a, 91 and H9, the vertically arranged tubes may be eliminated and the liquid refrigerant may be directly vaporized in the chambers of said units.

Furthermore, if the systems are, constructed, however, to cool fluids in said chambers, coils of any desired form, shape or make may be used and substituted and arranged in any desired manner in place of the vertically arranged tubes and liquid refrigerant vaporized in said coils. Since I have shown coils and tubes in my condenser 90, Fig. 4, I do not wish to be limited to this construction because coils may be substituted for the vertically arranged tubes either in intermingled relation with the other coils, or the coils of both circuits may be arranged one above the other or in any other desired manner.

It will be obvious to those skilled in the art that various changes may be made inmy devices without departing from the spirit of the invention and Itherefore do not limit myself to what is shown in the drawings and described in the speciflcation, but only as set forth in the appended claims.

I claim:

1. A refrigerating system comprising, in combination, a primary refrigerating circuit including a compressor, a condenser, an expansion valve and an evaporating element connected in a closed circuit, and a second lower boiling point refrigerant circuit including a compressor, a condenser cooledby said primary circuit, a liquid receiving and cooling element and an expansion valve and an evaporator connected in a closed circuit, said cooling element and said evaporator being located in a housing, and means for circulating a medium to be cooled over said cooling element and said evaporating elements.

2. A refrigerating system comprising, in combination, a primary refrigerating circuit including a compressor, a condenser, an expansion valve and an evaporator connected in a closed circuit,fand a second circuit employing a refrigerant oflower boiling point, including a compres-, sor, a condenser cooledby said primary circuit and an evaporator unit connected :in a closed circuit, said last mentioned evaporator unit comthe cooling element and jsaid evaporating elements being located in said housing and having communication with the discharge 'ofthe second mentioned condenser and the expansion valve, valve controlled connections at the inlet and outlet ends of said cooling element whereby the lower boiling point refrigerant from the second-mentioned condenser may be conveyed directly to the expansion valve of the secondmentioned evaporator unit, and means for circulating a medium to be cooled over said cooling element and said evaporating elements.

3. A refrigerating system comprising, in combination, a primary circuit employing a refrigerant of high boiling point and including a compressor, a condenser, a liquid cooling element, an expansion valve and evaporating elements connected in a closed circuit in the order named; and a second circuit employing a refrigerant of lower boiling point and including a compressor, a condenser cooled by said primary circuit, an expansion valve and an evaporator connected in a closed circuit in the order named; the liquid cooling element of said primary circuit and the condenser of said second circuit and the evaporating elements of the primary circuit being incorporated in a single closed housing and in heat exchange relation.

4. A refrigerating system comprising, in combination, a primary circuit employing a refrigerant of high boiling point and including a compressor, a condenser, a liquid receiving and cooling element, an expansion valve and evaporating elements connected in a closed circuit in the order named; and a second circuit employing a refrigerant of lower boiling point and including a compressor, a condenser cooled -by said primary circuit, a liquid receiving and cooling element, an expansion valve and evaporating elements connected in a closed circuit in the order named; the liquid receiving and cooling element of said primary circuit, the condenser of the second circuit and the evaporating elements of the primary circuit being incorporated in a single closed housing and in heat exchange relation, while the liquid receiving and cooling element of the second circuit and the evaporating elements of the second circuit are incorporated in a single closed housing and in heat exchange relation.

5. A refrigerating system for low temperature and quick freezing refrigeration involving a compressor, a condenser, liquid refrigerant pressure boosting means, a liquid receiving and cooling element, an expansion valve and an evaporating element arranged in a closed circuit in the order named, means for further cooling the liquid in said cooling element; valved controlled connections intermediate of the. condenser, said liquid refrigerant pressure boosting means, said cool ing element and said expansion valve whereby the direction of flow of the refrigerant relative to said means, cooling element and said expansion valve may be controlled; and a closed refrigerating circuit'adapted to cool said condenser.

'- evaporating elements connected in a closed circuitinqth-e-order named; and a second circuit employing a refrigerant of lower boiling point and including acompressor, a condenser cooled by said primary circuit, liquid pressure boosting means, a'liquid receiving and cooling element, an

expansion valve and. evaporating elements connected in a closed circuit in the order named,

the liquid cooling element and the evaporating elements being incorporated in a single housing and in heat exchange relation.

7. A refrigerating system comprising, in combination, a primary circuit adapted to employ a refrigerant of high boiling point and involving a compressor, a condenser, an expansion valve and evaporating elements connected in a closed circuit in the order named; and a second circuit adapted to employ a refrigerant of lower boiling point and including a compressor, a condenser cooled by said primary circuit liquid pressure boosting means, a liquid receiving and cooling element, an expansion valve and evaporating elements connected in a closed circuit in the order named, means arranged for further cooling the liquid in said cooling element; and a valve controlled by-pass whereby said liquid pressure boos-ting means may be operatively disconnected from said second circuit.

8. A refrigerating system for low temperature and quick freezing refrigeration involving a compressor, a condenser, liquid pressure boosting means, a liquid receiving and cooling element, an expansion. valve and evaporating elements arranged in a closed circuit in the order named, the cooling element and the evaporating ele ments being arranged in heat exchange relation,

valve controlled arrangements whereby theliqa liquid receiving and cooling element, an ex-' pansion valve, an evaporating element arranged in a closed circuit in the order named, the cooling element and said evaporating elements are arranged in heat exchange relation, and valve controlled connections whereby the liquid pressure pump and the liquid cooling element may beyeither singly or jointly operatively disconnected from saidcircuit at the will of the operator.

10. In a refrigerating system, a housing defining a chamber, an evaporating element arranged in said chamber, an expansion valve communicating with the inlet of said evaporating element, a condenser element arranged in said chamber, means for introducing and withdrawing a fluid medium into and from said element, a liquid receiving and cooling element arranged in said chamber, the discharge end of said element communicating with the expansion valve intermediate of said'evaporating element, and means for circulating a fluid medium through the chamber of said housing in 'heat' exchange relation with all of said elements.

11. A refrigerating system involving, in combination, a refrigerating circuit employing a refrigerant of low boiling point and comprising a pressure and low temperature condenser, a liquid pressure pump, liquid receiving and cooling means, an expansion valve, and evaporating elements arranged in the order named to form a closed refrigerating circuit, the cooling means and said evaporating elements being arranged in a housing in heat exchange relation with each other; a valve controlled connection intermediate of said condenser and the pump whereby liquid under low pressure and of low temperature from said condenser is available for other purposes; a valve controlled connection at the discharge end of said cooling means whereby liquid under high pressure and at a lower temperature is available for other purposes; and a closed refrigeration circuit employing a refrigerant of higher boiling point adapted to cool said condenser.

12. A refrigerating system involving, in combination, a refrigerating circuit employing a refrigerant of low boiling point and comprising a compressor, a gas-cooled condenser, a liquid pressure pump, liquid receiving and cooling means, an expansion valve, a refrigerating evaporator connected in a closed circuit, the cooling means and said evaporator being arranged in a single closed housing in heat exchange relation with each other, a valve controlled connection intermediate of said condenser and said pump whereby liquid under low pressure and low temperature from said condenser. is available for other purposes, a valve controlled connection between the compressor, a low pump and said expansion valve whereby the path of the boosted liquid may be determined, a valve controlled connection at the discharge end of said cooling means whereby liquid under high pressure and at a lower temperature is available for other purposes, and valve controlled connections communicating with the inlet side of said compressor whereby evaporated refrigerant and additional refrigerant may be conveyed to the compressor.

13. In a-refrigerating system, a housing defining a chamber comprising headers at opposite ends, a plurality of evaporating elements connecting the headers at opposite ends, an expansion valve communicating with the inlet header, a plurality of cooling elements arranged in said chamber in heat exchange with said evaporating elements, valve controlled means whereby said cooling elements may be operatively disconnected,

a liquid receiving and cooling element arranged in the header at the discharge ends of the evaporating elements, valved connections between said element and the expansion valve, and means for circulating a fluid medium through said cooling chamber.

14. The process of refrigeration which consists in compressing, condensing and vaporizing a refrigerant of relatively high boiling point in a continuous cycle, compressing, condensing and liquefying a refrigerant of low boiling point at relatively low condenser pressure by utilizing the refrigerating action of the high boiling point refrigerant for condensing the refrigerant of low boiling point, boosting the pressure of the cold liquid refrigerant of low boiling point, vaporizing said liquid refrigerant of low boiling point and utilizing the expanding refrigerant of low boiling point to pro-cool oncoming liquid refrigerant of low boiling point before expansion, returning the vaporized refrigerant for recompression and recondensing under low circulating a fluid medium to be-cooled in heat exchange relation with the vaporized and precooled high pressure liquid refrigerant.

condenser pressure, and

aromas 15. A two stage refrigerating system involving, in combination, a primary circuit comprising a compressor, a condenser, liquid cooler, expansion valve and an evaporator, arranged in the order named to form a closed refrigeration circuit; a second circuitcomprising' a compressor, a gas cooler, a condenser, a liquid cooler, an expansion valve'and an evaporator, arranged in the order named to form a closed refrigeration circuit; said gas cooler of the second circuit and the condenser of the primary circuit being incorporated in a closed housing, means whereby a cooling medium may be circulated through said housing; the condenser of the second circuit and the liquid cooler and the evaporator of the primary circuit being incorporated in a closed housing; the liquid cooler and the evaporator of the second circuit being incorporated in a closed housing.

16. A two stage refrigerating system involving, in combination, a primary circuit comprising a compressor, a condenser, a liquid cooling element, an expansion valve and an evaporator provided with headers at opposite ends, all of the elements being arranged in the order named to forrn-a closed refrigeration circuit; a second circuit using low boiling point refrigerant and comprising a compressor, a condenser, a liquid cooler; a liquid cooling element, an expansion valve and an evaporator provided with headers at opposite ends, said elements being arranged in the order named to form a closed refrigerating circuit; the condensers of the primary and of the second circuits being enclosed in a single closed housing and permitting operation with different refrigerants; the liquid cooler of the second circuit and the evaporator of the primary circuit being enclosed in a single housing; the first mentioned liquid cooling element being arranged in one of the headers of the evaporator of the primary circuit; and the second liquid cooling element being arranged in one of the headers of the evaporator 01 the second circuit.

1'7. In a refrigerating apparatus, a housing, defining a chamber and provided with headers at opposite ends, evaporating elements, tubes or coils disposed through the chamber and communicating with both of said headers, and a liquid refrigerant receiving and cooling element arranged in one of the headers of said housing and having valve controlled communication with the other header.

18. A refrigerating apparatus comprising a vertically arranged closed. housing defining a chamber provided with a header at the upper end, an exhaust discharge conduit connected to said header and communicating with the interior of said header, evaporating elements disposed through the chamber and communicating with said header, expansion means adjacent the inlet of. said evaporating elements, a liquid refrigerant receiving and cooling element arranged in said header of said housing, and means whereby a fluid medium may be circulated through the chamber of said housing.

19. In a refrigerating apparatus, a housing, provided with headers at opposite ends, evaporating elements disposed through the chamber and communicating with both of said headers, a liquid refrigerant receiving and cooling element arranged in one of the headers of said housing, valve controlled means for introducing a fluid medium into said chamber adjacent the discharge ends of the evaporating elements, valve controlled means arranged at spaced apart intervals in communication with said chamber whereby the if of a temperature lower than theinitially incoming fluid medium. I 20. A two stage refrigerating system consisting of two refrigerating systems cooperating with each other, one of said systems comprising a compressor, a condenser, expansion valve and an evaporator arranged in the order named to form a closed refrigeration circuit; the other system comprising a compressor, a condenser, a liquid receiving and cooling element, expansion 'valve and an evaporator arranged in the order named to form a closed refrigeration circuit; the condensers of the first and second system being arranged in a closed housing which is provided with valve controlled inlets and outlets for circulating a cooling medium through said housing in contact with both of said condensers; valve controlled elements whereby the liquid cooling element of the second system may be operatively disconnected from the condenser and evaporator of said second system and the discharge of the condenser of the second system directly connected with the expansion valve of said second system, the liquid cooling element of the second mentioned system and the evaporator of the first system being arranged in a closed housing, valve controlled means for circulating a fluid medium through said last mentioned housing in contact with said liquid cooling element and evaporator, whereby said systems may be converted into two independently operated systems. I

21. A refrigerating apparatus comprising a vertical arranged shell provided with an evaporating velement for vaporizing a refrigerant therein to cool brine in said shell, a plurality of cooling ele-, ments arranged in said shell for introducing a liquid to be cooled into said elements and means for withdrawing said liquid therefrom, said shell being provided with a plurality of inlets and outlets, all said inlets and outlets being arranged at different levels, said inlets and outlets providingmeans for withdrawing brine of different temperatures at different levels from the shell and returning said brine of difierent temperatures to the shell at differentlevels whereby an equal temperature may be maintained of the liquid to be cooled in said cooling elements.

22. A refrigerating apparatus consisting of a vertical arranged shell defining a chamber, provided with a plurality of inlets and a plurality of outlets, all-said inlets andoutlets being arranged at different levels, means for introducing brine into the chamber of the shell and for withdrawing the brine therefrom; evaporating element arranged in the chamber and forming part of a closed refrigerating circuit for cooling said brine,

a plurality of cooling elements arranged in the.

chamber of said shell, means for introducing a liquid to be cooled into said elements, means for withdrawing the cooled liquid therefrom; the

brine introduced at higher levels into the chamher being withdrawable from the chamber at lower levels or vice versa, whereby the temperature of the liquid to be cooled in said elements may be controlled and equalized.

23. The process of obtaining a liquid refrigerant of low boiling point under high pressure and medium low temperature in economical manner which consists in compressing, condensing, and vaporizing a volatile refrigerant in a continuous cycle, compressing, condensing and liquefying a gaseous I refrigerant of low boiling point at relatively low chamber, a refrigerating element disposed in said chamber, expansion means at the inlet of said .element, a plurality of. inlet and a plurality of outlet valved connections communicating with said chamber at different, points whereby a cooled in saidchamber may be withdrawn at different temperatures and returned to the chamber at different levels and at diiferent temperatures.

25. Refrigerating apparatus of the character described comprising three units, one of said units volatile refrigerant, boostcomprising two cooling elements'with fluid passages therebetween, a second unit comprising an evaporator element and a condenser element with fluid passages therebetween, while the third unit comprises an evaporator, a' compressor connected with the first and second unit, an expansion valve for the second unit; valve controlled connections between said first and second units and said compressor-whereby a closed refrigeration circuit is established; an expansion valve for the third mentioned unit, a compressor connected to the discharge of the third unit and connected with the first unit; valve controlled connections between all of said units whereby the refrigerant may circulate through all of the units; and valve controlled connections whereby the units may be operatively disconnected into separate independent systems wherein onesystem involves the first mentioned compressor, first mentioned unit and second mentioned unit, while theother system involves the second mentioned compressor, the first mentioned unit and the third mentioned unit.

26. In a mechanical refrigerating apparatus of the character described, a suitable housing, an evaporating element, a liquid refrigerant receiving and cooling element arranged in heat exchange relation with the discharge of the evaporating element, and communicating with the entrance of said evaporating element, an expansion valve associated with said evaporating element, and a separate closed fluid conveying passage for introducing and withdrawing a fluid to be cooled, arranged in the housing, free passages intermediate of said elements, separate means whereby difi'erent mediums may be circulated through said elements, a conduit for introducing a medium to be cooled in the housing to pass in counterflow to the refrigerant in the evaporating element, and .a plurality of valved connections whereby a medium may be withdrawn from the housing at different points and different tem-- peratures.

1O ranged in the lower part in the interior of said shell; means for introducing and withdrawing a fluid to be cooled into and from said element whereby the refrigerant circulated in said closed circuit will'be successively in heat exchange relation first with said last mentioned'cooling ele- I ment and then with said first mentioned cooling element. Y

28. In a two'stage refrigerating system involving two refrigerating systems cooperating with each other, the first system consisting of a compressor, a condenser, a liquid receiving and cooling element, an expansion valve, and an evaporating element; the second system consisting of a compressor, a brine cooled condenser consisting of a shell provided with a condenser element and brine inlets and outlets, a liquid receiving and cooling element, and an evaporator; the liquid receiving and cooling element and the evaporating eleme t of theflrst system being arranged in said brine cooled condenser, the liquid receiving and cooling element of thesecond system being arranged in heat exchange relation in the path of the vaporized refrigerant of the same i system; the first system being vadapted to cool the brine for said brine cooled condenser of the second system.

29. The process of refrigeration which consists in-compressing and condensing a volatile refrigerant gas in a plurality of stages, utilizing a'cooling medium of atmospheric temperature to cool the compressed refrigerant gas in the first stage, and utilizing a cooling medium lower than atmospheric temperature to further cool'the liquid refrigerant in the second" stage as the cooling medium; boosting the pressure of a volatile liquid refrigerant, utilizing the vaporized refrigerant in a third stage as a cooling mediumfor further cooling the boosted volatile liquid refrigerant before vaporization, and recompressing the vaporized volatilerefrigerant in a continuous cycle..

30. A two stage refrigerating system comprising two systems cooperating with each-other, one system comprising a compressor, a condenser element, a liquid cooling element, a liquid control valve and an evaporating element, all arranged to form a closed refrigeratingcycle, the cooling element being arranged in heat exchange relation withthe exhaust gas of the evaporating element;

, the other system comprising a compressor, a'condenser element, a liquid cooling'element, a liquid control valve, and an evaporating element, all

order named to form a closedarranged in the refrigerating circuit the evaporating element of the first system and the condenser element of the second system being arranged in heat exchange relation, the second mentioned cooling element and the second mentioned evaporating element being arranged in closed housing with free passages between all of said elements; and means for conveying a fluid medium to be cooled through said housing in-heat exchange relation with all of said elements. 7

frigeration circuit;

31. The process of refrigeration which consists in compressing, cooling, condensing and handying a volatile refrigerant gas at relatively low pressure and low temperature, utilizing a second vaporized volatile refrigerant preferably of higher boiling point than saidjfirst mentioned refrigerant to cool, condense, and llquefy said first mentioned refrigerant gas at said low pressure and low temperature, boosting the pressure of the f volatile liquid refrigerant, vaporizing the high pressure liquid refrigerant to obtain a low refriiieratingtemperature, recompressing and recooling the volatile gaseous refrigerant at said relatively low pressure and low temperature.

32. In a refrigerating system ture work, a compressor, a condenser element, a liquid refrigerant pump, a liquid receiving and cooling element for cooling the liquid refrigerant of increased pressure introduced thereinto, an expansion valve, and an evaporating element, connected in the order named to forms closed resaid refrigerant pump being connected so that the pressure of the liquid refrigerant in the liquid receiving and cooling element may be increased as desired and to thereby increase the pressure drop between the evaporator and the liquid receiving and cooling element and to simultaneously increase the ef-' ficiency thereof; said liquid receiving element being arranged in heat exchange relation with the discharge of said evaporating element,

for low tempera- 33. A refrigerating system for low temperature and quick freezing refrigeration, comprising a cooling element, an evaporator arranged order named, means for further cooling the liquid refrigerant in said liquid cooling element, a valve controlled connection intermediate of said condenser and said liquid receiving and cooling element whereby the direction of flow of the refrigerant relative to the said expansion valve and the liquid receiving and cooling element may be controlled; and a closed refrigeration cycle arranged for cooling said condenser.

34. In a mechanical refrigerating apparatus of the character described, comprising a vertical arranged housing, an evaporating element 'arranged in the housing forintroducing and withdrawing a refrigerant and a separate closed fluid expansion valve andv an conveying passage for introducing and withdraw-' in 'aclosed circuit in the Oil