US2056016A

US2056016A - Flow controlling device for refrigerating systems

Info

Publication number: US2056016A
Application number: US59739A
Authority: US
Inventors: Delbert F Newman
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1936-01-18
Filing date: 1936-01-18
Publication date: 1936-09-29
Anticipated expiration: 1953-09-29

Description

Sept. 29, 1936. D. RNEWMAN FLOW CONTROLLING DEVICE FOR REFRIGERATING SYSTEMS Filed Jan. 18, 1936 Figi L Inventor":

Patented Sept. 29, 1936 UNITED sTATEs PATENT OFFICE FLOW CONTROLLING DEVICE FOR REFRIGERATING SYSTEMS New York AppllcationJanuary 18, 1936, Serial No. 59,739 6 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.

It has heretofore been proposed to utilize long capillary tubes having a comparatively small inside diameter to maintain the required difference in pressure between the high and low pressure sides of a refrigerating system. Such a device must be arranged to restrict the flow of vaporized refrigerant from the high pressure side of the system to the low pressure side thereof, while at the same time permitting the flow of sufllcient liquid refrigerant therethrough to meet the capacity requirements of the system at the lowest pressure difference prevailing between the high and low pressure sides of the system during the normal operation thereof. Although such capillary tubes are simpler and more economical to construct than the 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 refrigerating systems,

such capillary tubes are nevertheless bulky and' susceptible to damage since such a tube may be easily crushed thus shutting 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 flow of refrigerant between the high and low pressure sides of a refrigerating system which comprises an improved arrangement of sheet metal parts that are economical to manufacture, the flow controlling device being effective in operation and rugged in construction.

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.

For a better understanding of my invention, reference may be had to the accompanying drawing in which Fig. 1 is a side elevation, partly in 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 the flow controlling device shown in Figs. 1 and 2, portions of the flow controlling device being broken away in order to better illustrate the internal construction thereof; Fig. 4 is a sectional view along the line 4-4 of the new controlling device shown in Fig. 3;

Fig. 5 is a developed view of a modified form of fiow controlling device, embodying my invention, which may be used in the refrigerating machine shown in Fig. 1, and Fig. 6 is a sectional view along the line 6-6 of the flow controlling device shown in Fig. 5. I

Referring to the drawing, I have shown in Fig. 1 a refrigerating machine, designed for household use, which includes a motor driven compressor unit contained in a cylindrical hermetically sealed casing Ill-mounted on the upper side'of a removable heatinsulated top wall I I of the refrigerator cabinet in which the refrigerating machine is used. Compressed vaporized refrigerant, such as sulphur dioxide, is supplied from the compressor contained in the casing ID to a cylindrical sheet metal condenser I2 which surrounds the casing I0 and is mounted thereon. The compressed gaseous refrigerant thus supplied to the condenser I2 circulates through a helical refrigerant circulatory passage I3 formed in the condenser I2 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 up- ,wardly over the surfaces of the condenser I2 and between the condenser and the casing I0 by natural draft. The refrigerant thus liquefied in the condenser I2 flows through a conduit I 4 to a cylindrical receiver I5 which is mounted on'the wall II. Liquid refrigerant accumulated in the receiver I5 flows therefrom through a conduit I6 -to a flow controlling device I! embodying my invention and is supplied therefrom through a liquid line I8 to a flooded type sheet metal evaporator I9.

The evaporator I9 is supported on the lower side of the wall [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 2I 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 I0 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 |1 includes an elongated substantially rectangular sheet of metal 23 and complementaryrectangular sheets of

metal

24 and 25, which are arranged on opposite sides of the sheet of metal 23 and conform thereto throughout their length. The sheets of

metal

23, 24, and 25 are preferably made of cold-rolled steel. A relatively narrow elongated zigzag slot is formed in the sheet of metal 23. This elongated slot preferably includes a plurality of transverse slots 26 arranged in substantially parallel relation. These slots 26 are connected in series relation by a plurality of longitudinal slots 21 arranged at the alternate opposite ends thereof and extending between the adjacent end portions of the transverse slots 26. It will be noted that the longitudinal slots 21 communicate with the transverse slots 26 intermediate the'ends thereof, so that small recesses or pockets 28, arranged in alignment with the adjacent portions of the transverse slots 26, are formed at the opposite ends of the latter. Since the recesses 28 are located adjacent the reentrant bends formed-in the zigzag or sinuous fluid passage composed of the slots 26 and 21, the recesses serve to increase the turbulence of any vaporized refrigerant as it flows from the slots 26 to the slots 21 or from the slots 21 to the slots 26. Both the slots 26 and 21 are of relatively small cross section in order to restrict or substantially prevent the flow of vapor therethrough. The slots 26 and 21 are preferably about .001 square inch in cross sectional area when the flow controlling device is used with a refrigerating machine having a capacity of about 550 B. t. u.s per hour, using sulphur dioxide as a refrigerant, and operating in. an ambient temperature of F. The provision of a flow controlling device for controlling thev flow of refrigerant between the high and low pressure sides of a refrigerating system and comprising a member having a plurality of fluid passages formed therein and arranged in substantially parallel relation, and an arrangement including a plurality of connecting passages formed in said member for connecting the fluid passages in series relation, the connecting passages being arranged at alternate opposite ends of the fluid passages and communicating with adjacent end portions thereof intermediate the ends of said fluid passages is not my invention, but is the invention of Christian Steenstrup and is described in his copending application Serial No. 59,756, filed January 18, 1936, and assigned to the General Electric Company, the assignee of my present invention.

The sheet of metal 25 is preferably of the same peripheral dimensions as the sheet of metal 23, while the sheet of metal 24 is. somewhat wider than the

sheets

23 and 25. The

longitudinal edges

29 and 30 of the sheet 24 are folded over the adjacent longitudinal edges of the

sheets

23 and 25 and the sheets are brazed or otherwise hermetically sealed together. Complementary semi-cylindrical indentations 3| and 32 are formed in the sheets of

metal

24 and 25, respectively, at adjacent ends thereof. The indentations 3| and 32 are tightly fitted around the lower end of the conduit l6 and are brazed or otherwise. hermetically sealed thereto. One of the slots 26, located at an end of the series of such slots, communicates with the complementary indentations 3| and 32. A similar pair of complementary

semi-cylindrical indentations

33 and 34 are formed in the sheets of

metal

24 and 25, respectively, and communicate with the one of the slots 26 located at the opposite end of the series of such slots. These

indentations

33 and 34 are tightly fitted on the upper end of the liquid line l8 being brazed or otherwise hermetically sealed. thereto and thus forming an outlet for the flow controlling device l1.

In making the flow controlling device H described above, the slots 26 and 21 as well as the recesses or notches 28 are punched or otherwise formed in the sheet of metal 23. The complementary indentations 3|, 32, 33, and 34 are stamped or otherwise formed in the flat sheets of

metal

24 and 25. The sheets of

metal

24 and 25 are then arranged in face contact with the sheet of metal 23 on opposite sides thereof and in such position that they conform with each other throughout substantially their entire lengths. The

edges

29 and 30 of the sheet of metal 24 are then folded over the adjacent edges of the sheets of

metal

23 and 25. The sheets of

metal

23, 24, and 25 are then brazed together throughout the area of the contacting surfaces thereof or are otherwise hermetically secured together. After having been thus secured together the sheets of

metal

23, 24,and 25 are then wound into a helical form, their finished shape being illustrated in Fig. 2. Thermal insulation 35 is arranged between adjacent layers of the helically wound sheets of metal in order to prevent the transfer of heat between bodies of refrigerant passing through the fluid passage made up of the slots the adjacent portions of the flow controlling device. The flow controlling device |1 thus formed is preferably mounted in the heat insulation ||a of the refrigerator cabinet wall I.

It will thus be seen that the

slots

26,21, and 28, formed in the sheet of metal 23, cooperate with the adjacent portions of the sheets of

metal

24 and 25 to form an elongated sinuous or zigzag flow controlling refrigerant passage of sufficient 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 difference existing between the high and low pressure sides of the system during the normal operation thereof. The pockets or recesses 28 are particularly useful in preventing the flow of vaporized refrigerant through the sinuous fluid passage formed by the slots 26 and 21 in that the turbulence of the vapor which changes direction of flow at the junctions between the slots 26 and 21 is increased by the 'recesses 28 into which a portion of the vapor flows. That is, when the vapor flows along the slots 26, for example, it tends to continue in the same direction of flow and thus enters the recesses 28. Upon striking the closed ends of the recesses 28, the vapor rebounds and turbulenbe therein 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 slots 26 and 21, however, much I less turbulence is set up therein by the recesses 28 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 26 and 21 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. It is particularly desirable to form the refrigerant passage in the flow controlling device by slots in a sheet of metal rather than by indentations in a sheet of metal, for example, because the shearing die ordinarily used in forming the slots is less subject to wear than a compression or stamping die. a sheet of metal are subject to variations in size because of differences in the granular structure or thickness of the metal. Hence, the slots are of more uniform size than would be indentations.

When the slotted sheets of metal 23 are handled and especially when they are handled in large quantities during factory production thereof, they may become twisted or skewed, that is, the longitudinal edges of the slotted sheets 23 may be moved lengthwise relative to each other so that some of the slots 26 and 21 are narrowed and others are widened thus materially changing their resistance to the flow of fluids therethrough. In Figs. 5 and 6, I have shown a modified form of flow controlling device Ila, embodying my invention, which is very similar to the flow controlling device ll described above but in which this difficulty is obviated.

The flow controlling device Ila includes an elongated substantially rectangular sheet of metal 23a and complementary rectangular sheets of

metal

24a and 25a which are arranged on opposite sides of the sheet of metal 23a andconform thereto throughout their length. The

' sheets of met-a1 23a, 24a, and 250. are preferably made of cold-rolled steel. A series of relatively narrow elongated zigzag slots are formed in the sheet of metal 23a. These elongatedslots preferably include a plurality of transverse slots 26a arranged in substantially parallel relation.

Groups of these slots 26a are connected in series relation by a plurality of longitudinal slots 21a arranged at the alternate opposite ends thereof and extending between the adjacent end portions of the transverse slots 2601.. It will be noted that the longitudinal slots 21a communicate with the transverse slots 26a intermediate the ends thereof so that small recesses or pockets 28a, arranged in alignment with the adjacent portions of the, transverse slots 26a, are formed in the opposite ends of the latter. Since the recesses 28a are located adjacent the reentrant bends formed in the zigzag or sinuous fluid passages composed of the slots 26a and 21a, the recesses serve to increase the turbulence of any vaporized refrigerant as it flows from the slots 26a to the slots 21a or from the slots 21a to the slots 26a. Both the slots 26a and 21a are of relatively small cross section in order to restrict or substantially prevent theflow of vapor therethrough. The slots 26a and 21a are preferably about .001 sq. in. in cross sectional area when the flow controlling device is used with a refrigerating machine having a capacity of about 550 B. t. u.s per hour, using sulphur dioxide as a refrigerant, and

operating in an ambient temperature of F.

Moreover, indentations made inand described above, except that some of the connecting slots 21 in the sheet 23 are omitted in the sheet 23a. Consequently, the sheet 23a is much more rigid than the sheet 23 and is not likely to be skewed or twisted during handling. The sheet of metal 25a is preferably of the same peripheral dimensions as the sheet 230, while the sheet 24a is somewhat wider than the sheets 23:; and 25a. The

longitudinal edges

29a and 30a of the sheet 24a are folded over the adjacent longitudinal edges of the sheets 23a and 25a. and the sheets are brazedor otherwise hermetically sealed together. The plurality of zigzag passages formed by the slots 26a and 21a are connected in series relation by a plurality of indentations 24b formed in the sheet of metal 24a. These indentations 24b connect the adjacent end portions of the slots 26a intermediate their ends and extend across the unslotted por tions 23b of the sheet of metal 23a.-

Complementary semi-cylindrical indentations 3la and 32a are formed in the sheets of

metal

24a and 25a, respectively, at the adjacent ends thereof. The indentations 3la and 32a are adapted to be fitted around the lower end of the conduit 16 shown in Fig. l and may be brazed or otherwise hermetically sealed thereto. One of the slots 250, located at one, end of the series of such slots communicates with the complementary indentations 3la and 32. A similar pair of complementary semi-cylindrical inden- Ila. After the sheets of metal 23a, 24a, and

25a have been secured together as described above they are preferably bent into a compact helix.

It will thus be seen that the flow controlling device Ila is formed of relatively rigid parts i which may be easily handled during the manufacture thereof without danger of injuring the same. Also the slots 26a and 21a may be formed by a. shearing die in the sheet of metal 23a and, as a consequence, will have relatively uniform dimensions. Although the indentations 24b in the sheet of metal 24a. form a part of the fluid passage through the flow controlling device Ila, they constitute only a very minor part of the total length thereof. formed in the sheet of metal 241; will not have such uniform dimensions as a slot, for example, because of the inherent limitations, referred to above, of the stamping apparatus ordinarily used in producing such indentations. This variation in the dimensions of the indentations 24b will not, however, materially aifect the flow charac- The indentations 24b teristics of the fluid passage formed in the flow controlling device Ila since the total overall length of the indentations 24b is small as compared to the overall length of the slots 26a and 21a.

While I have shown two particular embodiments 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:

1. A flow controlling device for controlling the flow of refrigerant between the high and low pressure sides of a refrigerating system comprising a portion of sheet metal having an elongated relatively narrow slot formed therein, complementary portions of sheet metal, arranged on opposite sides of said slotted portion of sheet metal and conforming thereto substantially throughout their length, and means for hermetically securing all of said portions of sheet metal together, said second named portions of sheet metal closing the sides of said slot and cooperating therewith to form an elongated fluid passage.

2. A flow controlling device for controlling the flow of refrigerant between the high and low pressure sides of a refrigerating system comprising aportion of sheet metal having an elongated zigzag relatively narrow slot formed therein, complementary portions of sheet metal arranged on opposite sides of said slotted portion of sheet metal and conforming thereto substantially throughout their length, and means for hermetically securing all of said portions of sheet metal together, said second named portions of sheet metal closing the'sides of said zigzag slot and cooperating therewith to form an elongated fluid passage.

3. A flow controlling device for controlling the flow of refrigerant between the high and low pressure-sides of a refrigerating system comprising an elongated substantially rectangular sheet of metal having a relatively narrow zigzag slot formed therein, complementary substantially rectangular sheets of metal arranged on opposite sides of said slotted sheet of metal in face contact therewith and conforming thereto substantially throughout their length, the longitudinal edges of one of said being folded over the adjacent longitudinal edges of the other sheets of metal, and means for hermetically securing all of said sheets of metal together, said second named sheets of metal closing the sides ofv said slot and cooperating therewith to form an elongated fluid passage.

4. A flow controlling device for controlling the flow of refrigerant between the high and low pressure sides of a. refrigerating system comprising an elongated substantially rectangular sheet of metal having 'a plurality of transverse slots formed therein and arranged in substantially last named sheets of metal.

parallel relation, said sheet of metal having longitudinal slots therein arranged at alternate opposite ends of said transverse slots and extending between adjacent end portions thereof, said longitudinal slots communicating with said transverse slots intermediate the ends thereof, complementary rectangular sheets of metal arranged on opposite sides of said slotted sheet of metal in face contact therewith and conforming thereto substantially throughout their length, and means for hermetically securing all of said sheets of metal together, said second named sheets of metal closing the sides of said slots and cooperating therewith to form an elongated fluid passage.

5. A flow controlling device for controlling the flow of refrigerant between the high and low pressure sides of a refrigerating system comprising a portion of sheet metal having a plurality of elongated relatively narrow slots formed therein, complementary portions of sheet metal arranged on opposite sides of said slotted portion of sheet metal and conforming thereto substantially throughout their length, means for hermetically securing all of said portions of sheet metal together, said second named portions of sheet metal closing the sides of said slots and cooperating therewith to form a plurality of elongated fluid passages, and means including a plurality of indentations formed in at least one of said second named portions of sheet metal and extending between adjacent portions of said slots for connecting said elongated fluid passages in series relation.

6. A flow controlling device for controlling the flow of refrigerant between the high and low pressure sides of a refrigerating system comprising a portion of sheet metal having a plurality of elongated zigzag relatively narrow slots formed therein, complementary portions of sheet metal arranged on opposite sides of said slotted portion of sheet metal and conforming thereto substantially throughout their length, means for hermetically securing all of said portions of sheet metal together, said second named portions of sheet metal closing the sides of said zigzag slots and cooperating therewith to form a plurality of elongated fluid passages, and means including a plurality of indentations formed in at least one of said second named portions of sheet metal extending between adjacent portions of said slots for connecting said elongated fluid passages in series relation.

' DELBERT 'F. NEWMAN.