US2056022A - Flow controlling device for refrigerating systems - Google Patents

Description

c. STEENSTRUP 2,056,022

FLOW CONTROLLING DEVICE FOR REFRIGERATING SYSTEMS Sept; 29, 1936.

Filed Jan. l8, 1936 Inventov: Christian Steensbrwp,

Patented Sept. 29, 1936 UNITED STATES FLOW CONTROLLING DEVICE FOR BEFBIGEBATING SYSTEMS Christian Steenstrup, Schenectady, N. Y., assignor to General Electric Company, .a corporation of New York Application January 18, 1936, Serial No. 59,756 10. Claims. (Cl. 138-42) My invention relates to flow controlling devices for controlling the flow of refrigerant between the high and low pressure sides of refrigerating systems.

A vaporizable liquid refrigerant, such as sulphur dioxide, is ordinarily circulated through a closed refrigerating system in such manner that it is supplied in liquid form to an evaporator or other cooling unit in which the liquid is vaporized by the absorption of heat from articles to be cooled. The refrigerant thus vaporized then flows to a compressor-condenser unit or the like in which the vaporized refrigerant is first compressed by a suitable compressor and then liquefied by the transfer of heat therefrom toa cooling medium which flows in heat exchange relationship with the condenser. The refrigerant thus liquefied in the condenser is again supplied to the cooling unit and the cycle is repeated and continued until the desired cooling has been effected by the cooling unit. In such a system it is necessary to provide a pressure reducing device between the condenser, which is on thehigh pressure side of the system and the evaporator or other cooling unit which is on the low pressure side of the system, for regulating the flow of liquid refrigerant from the condenser to the evaporator.

An essential requirement of a satisfactory flow controlling device for the purpose described above is that it should prevent the flow of gaseous refrigerant after the liquid refrigerant has passed therethrough or should limit such flow to a very small amount. This requirement arises from the fact that a flow of gaseous refrigerant from the high pressure-side to the low pressure side of the refrigerating system results in a loss in capacity and efficiency of the system. At the same time the flow controlling device must permit a sufficient quantity of liquid refrigerant to flow therethrough to meet the capacity requirethan float valves or other devices having moving parts, which have heretofore been used as flow controlling devices between the high and 'low pressure sides of the refrigerating system,

such capillary tubes are nevertheless bulky and susceptible to damage since such a tube may be easily crushed thus cutting off the flow of refrigerant therethrough and rendering the refrigerating system inoperative.

' It is an object of my invention to provide a flow controlling device for controlling the How of refrigerant betweenthe high and low pressure sides of a refrigerating system which has an elongated refrigerant passage of improved form arranged therein, which substantially prevents the flowof vaporized refrigerant therethrough while at the same time permitting a sufficient quantity of liquid refrigerant to flow therethrough to meet the capacity requirements of the system at the lowest pressure different prevailing between the high and low pressure sides of the system.

It is a further object of my invention to provide a flow controlling device for controlling the flow of refrigerant between the high and low pressure sides of a refrigerating system which is compact, rugged, and economical to manufacture; being preferably made of portions of sheet metal hermetically secured together and having an elongated refrigerant flow controlling passage arranged therebetween.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my'invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Fora better understandingof my invention, reference may be had to the accompanying 'drawing in which Fig. 1 is a side elevation partly in 40 section of a refrigerating machine provided with a flow controlling device embodying'my invention; Fig. 2 is a perspective view of the flow controlling device of the refrigerating machine shown in Fig. 1; Fig. 3 is a developed view of cally sealed casing l0 mounted on the upper side of a removable heat insulated top wall ii of the refrigerator cabinet with which the refrigerating machine is used. Compressed vaporized refrigerant, such as sulphur dioxide, is supplied from the compressor contained in the casing in to a cylindrical sheet metal condenser l2, which surrounds the casing in and is mounted thereon. The compressed gaseous refrigerant thus supplied to the condenser l2 circulates through a helical refrigerant circulatory passage l3 formed in the-condenser l2 and is liquefied by the transfer of heat therefrom to the cooling air which circulates over the surfaces of the condenser. The cooling air circulates upwardly over the surfaces of the condenser and between the con-- denser and the casing ID by natural draft. The refrigerant thus liquefied in the condenser l2 flows through a conduit I4 to a cylindrical receiver l5, which is mounted on the wall ll. Liquid refrigerant accumulated in the receiver l5 flows therefrom through a conduit l6 to a flow controlling device [1, embodying my invention, and is supplied therefrom through a liquid line l8 to a flooded type sheet metal evaporator IS.

The evaporator I 9 is supported on the lower side of the wall i i in a refrigerator cabinet food storage compartment, the contents of which is to be cooled. The evaporator i9 is provided with a plurality of refrigerant circulatory passages 20 which communicate with a longitudinal cylindrical header 2| below the normal liquid level therein. The header 2| is maintained about half full of liquid refrigerant and the refrigerant circulatory passages 20 are thus flooded with liquid refrigerant. The liquid refrigerant contained in the evaporator i9 is vaporized by the absorption of heat from the compartment in which the evaporator is located and the refrigerant thus vaporized is collected in the header 2| above the level of the liquid refrigerant therein. The vaporized refrigerant thus collected in the header 2| is returned to the compressor in the casing l0 through a suction conduit 22 which communicates with the header 2! above the normal liquid level therein. This cycle is repeated and continued until the temperature of the compartment in which the evaporator I9 is located is reduced to the desired value.

The flow controlling device i1 includespcomplementary rectangular portions or sheets of metal 23 and 24, which are preferably made of cold-rolled steel. A plurality of transverse indentations 25, arranged in substantially parallel relation, are formed in the sheet 24. These indentations 25 are connected in series relation by a plurality of longitudinal indentations 26 arranged at alternate opposite ends thereof and extending between the adjacent end portions of the transverse indentations 25. It will be noted that the longitudinal indentations 25 communicate with the transverse indentations 25 intermediate the ends thereof so that small recesses or pockets 21, arranged in alignment with the adjacent portions of the transverse indentations 25, are formed at the opposite ends of the latter- Since the recesses 21 are located adjacent the reentrant bends formed in the zigzag or sinuous fluid passage composed of the indentations 25 and 26, the recesses serve to increase the tur: bulence of any vaporized refrigerant as it flows from the indentations 25 to the indentations 26 or from the indentations 26 to the indentations 25. Both the indentations 25 and 26 are of relatively small cross-section in order to restrict or substantially prevent the flow of vapor therethrough. The indentations 25 and 26 are preferably about .001 square inch in cross-sectional area when the flow controlling device is used with a machine having a capacity about 550 B. t. u.s per hour under an ambient temperature of F. and using sulphur dioxide as a refrigera'nt.

The sheet of metal 23 is preferably flat and somewhat wider than the sheet 24. The longitudinal edges 28 and 29 of the sheet 23 are folded over the adjacent longitudinal edges of the sheet 24 and the sheets are brazed or otherwise hermetically sealed together. Complementary semi- 'cylindrical indentations 30 and 3| are formed in the sheets of metal 23 and 24, respectively. The indentations 30 and 3| are tightly fitted around the upper end of the liquid line i8 and are brazed or otherwise hermetically sealed thereto. One of the indentations 25 located at an end of the series of such indentations communicates with the complementary indentations 30 and 3|. A similar pair of complementary semi-cylindrical indentations are formed in the sheets'of metal 23 and 24 communicating with the one of the indentations 25 located at the opposite end of the series of such indentations. One of these latter complementary indentations is shown at 32. These indentations are fitted on the lower end of the conduit l6, being brazed or otherwise hermetically sealed thereto, and thus forming an inlet for the flow controlling device H.

In making the flow controlling device I! described above, the indentations 25 and 26 are stamped or otherwise formed in the sheet of metal 24. The complementary indentations 3i and 32 are also preferably formed by the same stamping operation. Complementary indentations are also stamped or otherwise formed in the sheet of metal 23 to cooperate with the indentations 3| and 32 to form an inlet and an outlet for the flow controlling device. The sheets of metal 23 and 24 are then arranged in face contact in which position they conform with each other throughout substantially their entire lengths. The edges 23 and 29 of the sheet of metal 23 are then folded over the adjacent edges of the sheet of metal 24. The sheets of metal 23 and 24 are then brazed together throughout the area of the contacting surfaces thereof or otherwise hermetically secured together. After having been thus secured together the sheets of metal 23 and 24 are wound into a helical form, their finished shape being illustrated in Fig. 2. Thermal insulation 33 is arranged between adjacent layers of the helically wound sheets of metal 23 and 24 in order to prevent the transfer of heat between bodies of refrigerant passing through the fluid passage made up of the indentations 25 and 26 in the adjacent portions of the flow controlling deyice. The flow controlling device I! thus formed is preferably mounted in the heat insulation Ha of the refrigerator cabinet wall I I.

The indentations 25, 26 and 21 formed in the sheet 24 cooperate with the adjacent portions of the sheet 23 to form an elongated sinuous iiow controlling refrigerant passage of suflicient length and sinuosity, as compared to its cross-sectional area, substantially to prevent the flow of vaporized refrigerant therethrough while permitting the quantity of liquid refrigerant to flow therethrough required by the capacity of the system at the lowest pressure diiference existing between the high and low pressure sides of the system during the .thus enters the recesses 21.

normal operation thereof; The pockets or recesses 21 are particularly useful in preventing the flow of vaporized refrigerant through the sinuous fluid passage formed by the indentations 25 and 26 in that the turbulence of the vapor which changes direction of flow at the junctions between the indentations 25 and 26 is increased by the recesses 21 into which a portion of the vapor flows. When the vapor flows along the indentations 25, it tends to continue in the samedirection of flow and Upon striking the closed ends of the recesses 21, the vapor rebounds and turbulence thereof results. This turbulence is, of course, increased as the speed of movement of the fluid is increased. When liquid refrigerant is flowing through the sinuous fluid passage formed by the indentations 25 and 26, however, much less turbulence is set up therein by the recesses 21 in view of the fact that the liquid ordinarily flows at a slower speed than the vapor flowing through the fluid passage and, consequently, the turbulence set up in the liquid upon a change in direction of its flow is less than in the case of the vapor. The flow controlling device, which I have illustrated, is compact and rugged and may be readily manufactured from sheet metal by well-known and economical manufacturing operations.

While I have shown a particular embodiment of my invention in connection with a compression type refrigerating machine, especially designed for household use, I do not desire my invention to be limited to the particular construction shown and described and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is: v

1. A flow controlling device for controlling the flow of refr gerant between the high and low pressure sides of a refrigerating system comprising a member having an elongated fluid passage formed therein of relatively small cross section, said fluid passage having a plurality of reentrant bends formed therein, and said member having a plurality of recesses formed therein communicating with said fluid passage adjacent said reentrant bends thereof, the outer ends of said recesses being closed.

2. A flow controlling device for controlling the flow of refrigerant between the high and low pressure sides of a refrigerating system comprising a member having an elongated fluid passage formed therein of relatively small cross section, v

i said fluid passage having a plurality of reentrant bends formed therein, and said member having a plurality of recesses formed therein arranged in alignment with adjacent portions of said fluid passages and communicating therewith, the outer ends of said recesses being closed.

3. A flow controlling device for controlling the flow of refrigerant between the high and low pressure sides of a refrigerating system comprising a member having a plurality of fluid passages formed therein and arranged in substantially parallel relation, and means including a plurality of connecting passages formed in said member for connecting said fluid passages in series relation, said connecting passages being arranged at 8.1-: ternate opposite ends of said fluid passages and communicating with adjacent end portions thereof intermediate the ends of said fluid passages.

4. A flow controlling device for controlling the flow of refrigerant between the high and low pressure sides of a refrigerating system comprising complementary portions of sheet metal conforming with each other substantially throughout their length, and means for hermetically securing said portions of sheet metal together, said portions of said metal having an elongated fluid passage extending therebetween, said fluid passage having a plurality of reentrant bends formed therein, said portions of said metal having a plurality of recesses arranged therebetween and communicating with said fluid passage adjacent said reentrant bends therein, the outer ends of said recesses being closed.

5. A flow controlling device for controlling the flow of refrigerant between the high and low pressure sides of. a refrigerating system comprising complementary helical portions of sheet metal conforming with each other substantially .throughout the helical portions thereof, and

means for hermetically securing said portions of said sheet metal together, said helical portions of sheet metal having an elongated fluid passage of relatively small cross-section extending therebetween. l

6. A flow controlling device for controlling the flow of refrigerant between the high and low pressure sides of a refrigerating system comprising complementary helical portions of sheet metal conforming with each other substantially throughout the helical portions thereof, means for hermetically securing said portions of sheet metal together, said helical portions of sheet metal having an elongated fluid passage of. relatively small cross section extending therebetween, and means including thermal insulation arranged between adjacent layers of said helical portions of sheet metal for preventing the transfer of heat between bodies of fluid contained in adjacent portions of said fluid passage.

'7. A flow controlling device for controlling the flow of refrigerant between the high and low pressure sides of a refrigerating system comprising complementary helical portions of sheet metal conforming with each other substantially throughout the helical portions thereof. and arranged in face contact, at least one of said helical portions of. sheet metal having an elongated sinuous indentation formed therein of relatively small cross section, and means for hermetically securing said helical portions of sheet metal together. I r

8. A flow controlling" device for controlling the flow of refrigerant between the high and low pressure sides of a refrigerating system comprising complementary portions of sheet metal conforming with each other substantially throughout their length and arranged in face contact, at least-one of said portions of sheet metal having an elongated indentation of relatively small cross section formed therein. said indentation having a plurality of reentrant bends, at least one of said portions of sheet metal having a plurality of recesses therein communicating with said indentation adjacent said reentrant bends, the outer ends of said recesses being closed, and means for hermetically securing said portions of sheet metal together.

9. A flow controlling device for controlling the flow of refrigerant between the high and low pressure sides of a refrigerating system comprising complementary portions of sheet metal conforming with each other substantially throughout their length and arranged in face contact, at least one of said helical portions of sheet metal having a plurality of indentations therein arranged in substantially parallel relation, means including a plurality of indentations formed in at least one of. said portions of sheet metal to provide connecting passages for connecting said first named indentations in series relation, said connecting passages being arranged at alternate opposite ends of said first named indentations and extending between adjacent end portions thereof, said connecting passages communicating with said first named indentations intermediate the ends thereof, and means for hermetically securing said portions of sheet metal together.

10. A flow controlling device for controlling the flow of refrigerant between the high and low pressure sides of a refrigerating system comprising complementary elongated helical portions of sheet metal conforming with each other substantially throughout the helical portions thereof and arranged in face contact, at least one of said helical portions of sheet metal having a plurality of transverse indentations formed therein and arranged in substantially parallel relation, at least one of said helical portions of sheet metal having a plurality of longitudinal indentations therein arranged at alternate opposite ends of said transverse indentations and extending between adjacent end portions thereof, said longitudinal indentations communicating with said transverse indentations intermediate the ends thereof, means for hermetically securing said helical portions of sheet metal together, and means including thermal insulation arranged between adjacent layers of said helical portions of sheet metal for preventing the transfer of heat between bodies of fluid contained in adjacent portions of said indentations.

CHRISTIAN STEENS'IRUP.

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