US2986901A - Refrigerant evaporator - Google Patents

Description

June 6, 1961 E. F. HUBACKER REFRIGERANT EVAPORATOR Filed March 13, 1959 2 Sheets-Sheet 1 INVENTOR. 20/ a M- way Mn June 6, 1961 E. F. HUBACKER REFRIGERANT EVAPORATOR 2 Sheets-Sheet 2 Filed March 13, 1959 2,986,901 REFRIGERANT EVAPORATOR Earl F. Hubacker, Evansville, Ind., assignor to Whirlpool Corporation, a corporation of Delaware Filed Mar. 13, 1959, Ser. No. 799,287 7 Claims. (Cl. 62-276) This invention relates to a refrigerator.

The refrigerator of this invention is a two temperature device having a freezer compartment for freezing foods and storing frozen foods and a fresh food compartment adjacent thereto. customarily such refrigerators use a plurality of evaporators, one or more of which is located in the frozen food compartment and another or others located in the fresh food compartment. Although it is common to provide defrosting means for defrosting the evaporator in the fresh food compartment, it is somewhat uncommon to provide defrosting means for the frozen food compartment. The refrigerator of this invention provides a continuous evaporator having one portion in thermal contact with a first refrigerator compartment which may be the frozen food compartment and a second portion in thermal contact with a second refrigerator compartment which may be the fresh food storage compartment.

In a specific form this continuous evaporator is in the form of a continuous, integral, sheet evaporator with interconnected refrigerant flow passages therein with this continuous evaporator being shaped to have a first portion in thermal contact with the first compartment and the second portion spaced from the first portion in thermal contact with the second compartment. In another specific form single continuous heater means are associated with the continuous evaporator for defrosting all these portions of the evaporator substantially simultaneously.

One of the features of this invention is to provide a refrigerator comprising means forming a first compartment, means forming a second compartment, and a continuous, integral, sheet evaporator with interconnected refrigerant flow passages therein, the evaporator having a first portion in thermal contact with the first compartment for cooling the same and a second portion in thermal contact with the second compartment for cooling the same.

Another feature of the invention is to provide a refrigerator comprising means forming a first compartment, means forming a second compartment, a continuous evaporator with refrigerant flow passages therein, the evaporator having a first portion in thermal contact with the first compartment for cooling the same and a second portion in thermal contact with the second compartment for cooling the same, the refrigerator operating in successive on and off cycles with refrigerant flowing through said passages, first into the first portion passages and then into the second portion passages, and time delay means for delaying the flow of liquid refrigerant from said first portion into said second portion during each on cycle to produce a lower temperature in the first compartment than in the second compartment.

A further feature of the invention is to provide a refrigerator comprising means forming a first compartment, means forming a second compartment, a continuous, integral, sheet evaporator with interconnected refrigerant fiow pass-ages therein, the evaporator having a first portion in thermal contact with the first compartment for cooling the same and a second portion in thermal contact with the second compartment for cooling the same, and a continuous electric heater wire in thermal contact with said sheet for periodically defrosting the same.

Other features and advantages of the invention will be apparent from the following description of an embodi- Patented June 6, 1961 2 ment thereof as illustrated in the accompanying drawings. Of the drawings:

FIGURE 1 is a fragmentary vertical section through a refrigerator embodying the invention.

FIGURE 2 is a semi-diagrammatic perspective view of a continuous, integral, sheet evaporator forming a part of the refrigerator of FIGURE 1.

FIGURE 3 is a fragmentary sectional elevation taken substantially along line 3-3 of FIGURE 1.

FIGURE 4 is a wiring diagram of the refrigerator of FIGURE 1.

FIGURE 5 is a plan view of the evaporator of the refrigerator illustrating its details of construction and showing the sheet evaporator in planar form before being bent to the shape illustrated in FIGURE 2.

FIGURE 6 is a fragmentary sectional view taken substantially along the line 66 of FIGURE 5.

FIGURE 7 is an enlarged fragmentary plan view of a portion of the evaporator sheet of FIGURE 5.

The refrigerator shown in the accompanying drawings comprises a cabinet 10 having the usual walls including a top wall 11 and rear wall 12. The cabinet 10 is open at the front but is normally closed by means of an insulated door 13. This door is provided with the usual sealing gasket 14 adjacent the edge thereof for sealing against the cabinet 10.

The interior of the refrigerator 10 is provided with a substantially horizontal crossbar 15 adjacent the front of the cabinet and nearer the top wall 12 than the bottom of the cabinet. This crossbar 15 extends from side to side of the cabinet and has its front surface contacted by a gasket 16 mounted on the door 13. A separator 17 is provided extending rearwardly and downwardly at a small angle from the crossbar 15. This separator 17 is formed of a molded plastic tray 18 having a ribbed aluminum plate 19 attached to its bottom surface. At the sides of the plate 19 integral tabs 21 are bent downwardly to provide a rear mounting for the separator 17. The lower edges of these two side tabs 21 are notched as shown in FIGURE 3 and engage retaining pins 22. The front of the separator 17 is retained in place by engagement with the rear of the crossbar 15.

Located in the refrigerator is a continuous, integral, sheet evaporator 23 of the well known Rollbond construction. This comprises a pair of superposed sheets of metal joined together but separated at sections thereof to form refrigerant passages as illustrated at 24 in FIG- URE 6.

Mounted within the freezer or first compartment 25, which as shown is above the fresh food or second compartment 26, is the evaporator 23. This evaporator is made from a flat sheet as shown in FIGURE 5 and is bent on rounded curves as indicated by the areas A-A and B--B in FIGURE 5 to provide a top section 27, a rear section 28 and a bottom section 29. The bottom section is provided with a U-shaped cutout slot 30 so as to define an evaporator portion 31 that extends downwardly as indicated in FIGURES 1 and 2 so as to be located in the second compartment 26 of the refrigerator. The sections 27, 28 and 29 comprise a first portion of the evaporator for location in the freezer compartment 25 while the second portion extends down along the top of the inner surface of the rear wall 12 of the refrigerator. The top portion 27 of the evaporator is mounted on spaced studs 32 adjacent the front of this section while the front edge portion of the bottom section 29 rests on spacer studs 33 that are located adjacent the front crossbar 15. As is shown in FIGURE 1 the downwardly extending rear or second portion 31 of the evaporator sheet is substantially aligned with the rear section 28 and extends downwardly therefrom. This portion 31 serves as an evaporator for the compartment 26. The bottom of this portion 31 is through which air may flow from the compartment 26 down behind the evaporator portion 31 to provide air circulation. The material from the cutouts forming the slots 35 and 36 is bent rearwardly from the top as indicated in FIGURES l and 2. These cutouts 35 and 36 .also minimize heat transfer between evaporator portion 31 and the remainder of the evaporator sheet.

An important feature of this invention is the refrigerant flow circuit, illustrated in FIGURE 5, which not only cools the entire evaporator sheet 23 but also provides for a relatively low freezing temperature in the freezer compartment 25 and a relatively higher temperature in compartment 26 for the preservation of fresh food. This is accomplished by delaying the flow of refrigerant during each on cycle of the refrigerator into the refrigerant passages in the portion 31 of the evaporator. This provision of a time delay in this type of refrigerator which operates on successive on and off cycles and in which substantially no refrigerant flows through the system on an off cycle was found to be most efficient in controlling these temperature diiferentials. By means of this time delay in the flow of liquid refrigerant the liquid refrigerant is kept from entering the evaporator portion 31 until after a predetermined time. The illustrated means for accomplishing this time delay can best be understood from FIGURES and 7. As illustrated in FIGURE 5 a liquid refrigerant enters the evaporator 23 by means of a capillary 37. The capillary passes through a restricted portion 38 of the refrigerant passage so as to separate the incoming refrigerant from the outgoing refrigerant in a customary and well-known manner. From the exit of the capillary which is beyond passage portion 38 the refrigerant flows in a series of long parallel paths through the freezer sections of the evaporator sections 27, 28 and 29. Thus from the portion 38 the refrigerant flows through passages 39, 40, chambers 41, 42, passages 43 and into a single passage 44. As can be seen, from the capillary 37 to the single passage 44 the refrigerant flows in parallel paths and serves to cool the entire first portion of the evaporator made up of the top, rear and bottom sections 27, 28 and 29. This flow of the refrigerant is illustrated by the solid arrows. The various chambers in the evaporator including the chambers 41 and 42 as well as other illustrated chambers mentioned hereinafter are formed of wafiie embossed metal plates in the wellknown manner.

The portion of the evaporator containing the time delay features is best shown in the enlarged view of FIGURE 7. This time delay portion is located at the top section 27 of the evaporator which is at an angle of approximately from the horizontal as illustrated in FIGURE 1.

From the common passage 44 in the evaporator the refrigerant flows through this passage into a small header chamber 45. Since at this point there is the usual mixture of gaseous and liquid refrigerant the chamber 45 serves as a separation chamber. Thus liquid refrigerant flows out the bottom of the chamber 45 through passage 46 into the bottom of a large chamber 47 which because of the inclined configuration of top section 27 has its upper end at a higher elevation than its lower end int-o which the passage 46 empties. The gaseous refrigerant (whose flow is indicated in FIGURE 7 by dotted lines) flows out the top of the small chamber 45 into passage 48. This gaseous refrigerant flows down to the back section 28 of the evaporator and through a pair of successive flow restrictor passages 49 and 50. These are arranged in series and the back pressure of the gaseous refrigerant caused by these narrow restricted passages provides sufiicient pressure for a liquid head to slowly build up in the chamber 47. After a predetermined time which in one instance has been found to be about 4 minutes, the chamber 47 becomes filled with liquid refrigerant which then flows over an overflow passage 51 into and through a passage 52 and through a peripheral passage 53 around the edge of the depending evaporator portion 31. The refrigerant then continues its flow through passage 54 into the bottom entrance of main header chamber 55. This chamber 55 functions in the conventional manner of an accumulator and refrigerant gas flows outwardly through parallel passages 56, passage '57 and out through the suction line 58 in the conventional manner.

At the end of each refrigerating cycle the chamber 47 is substantially full of liquid refrigerant. During the off cycle, or period when the refrigerant compressor 64 is not running, this liquid slowly drains back down and out through passage 46, chamber 45 and through restrictors 49 and '50 into the accumulator 55.

Experimental results have shown that excellent results are achieved with this time delay feature. These tests indicate that in a 70 ambient room temperature a freezer temperature of approximately -3 F. and a refrigerator temperature of about 33 F. were maintained. In a F. ambient room temperature a freezer temperature of approximately 2 F. and a refrigerator temperature of approximately 35 F. were maintained. These tests show the excellent cross-ambient control obtained as a result of the present invention.

The refrigerator of this invention also employs improved means for substantially simultaneously defrosting the entire evaporator including those sections in the first or freezer compartment 25 and the portion 31 in the sec- 0nd or refrigerator compartment 26. In order to accomplish this defrosting a conventional resistance electric heater wire 59, shown in dotted lines in FIGURE 5 and shown in FIGURE 6, is provided. This heater wire runs from a point 60 to a point 61 and substantially covers the entire evaporator. As is shown in the enlarged detailed sectional View of FIGURE 6 this heater wire 59 is located in and attached to a trough-shaped portion 62 of the evaporator 23.

The electrical control circuit of the refrigerator illustrated in the drawings is shown in FIGURE 4. Connected to line L1 from a source of electric current is a switch 63 the other side of which is connected to the motor of a compressor 64. The other side of the compressor motor is connected by a line 65 to the normally closed contact 66 of a switch arm 67. This arm is connected to the line L2 which is adapted to be connected to the other side of the source of electric current.

The switch 63 is a conventional thermostatically controlled switch, the capillary bulb of which may be attached in the position indicated at 68 in FIGURE 5. The switch arm 67 is maintained normally closed to contact 66 by the defrost timing clock 69 of conventional construction. Thus, as indicated, the operation of the compressor 64 is controlled by the action of the thermostatically operated switch 63 which causes the compressor 64 to operate between two predetermined temperatures of evaporator 31 such as 5 F. and 15 F. The defrost clock has its motor connected for continuous running across the lines L1 and L2. At predetermined intervals, for example once every 24 hours, the arm 67 is caused to break the compressor circuit by breaking from contact 66 and closing against contact 70. This connects the line L2 to the arm 71 of the switch 72 which normally has the arm 71 closed against contact 73. This connects line L2 through switch arm 67 to one side of the electric heater wire 59, the other side of which is connected to line L1 through line .74. This action energizes the electricheater and provides for a quick defrosting of the entire evaporator 23. When the temperature of the refrigerator or second portion 31 of the evaporator at the point indicated at 68 reaches a predetermined temperature such as 35 the arm 71 of switch 72, which may be a bi-metal thermostat also attached at position 68, bends out of engagement with the contact 73 and into engagement with contact 75. This starts the operation of the compressor 64 even though the arm 67 of the time control switch is still in the down position. Thus the operation of the defrost heater 59 is terminated by a temperature control and not by a time control. However, it is the defrost operation that is begun by the time control. Of course, when the defrost clock again causes the arm 67 to move upwardly to the position shown in FIGURE 4 the compressor circuit returns to its normal condition. It will be apparent that switch 72 must be so adjusted that arm 71 will not snap back to engage contact 73 until after the predetermined time cycle for defrost is terminated and switch 67 has again closed on contact 66.

During the defrost cycle any accumulated frost is melted and the resulting water runs down the several evaporator surfaces and the compartment separator 17 to drop into the trough 76 which extends substantially the entire width of the refrigerator compartment 26. This trough is used to convey the water in the normal manner to a point outside the compartment 26 for disposal in the usual manner.

Thus the separator 17 in the refrigerator also serves to convey defrost water and the water flows from this separator and over a rear lip 77 to fall into the trough 76. This rear lip 77 is located in that portion of the plate 19 that is between the downward extending tabs 21 as indicated in FIGURE 3.

Having described my invention as related to the embodiment shown in the accompanying drawings, it is my intention that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A refrigerator, comprising: means forming a first compartment; means forming a second compartment; a continuous evaporator with refrigerant flow passages therein, the evaporator having a first portion in thermal contact with the first compartment for cooling the same and a second portion in thermal contact with the second compartment for cooling the same, the refrigerator operating in successive on and 0E cycles with refrigerant flowing through said passages, first into the first portion passages and then into the second portion passages; and time delay means for delaying the flow of liquid refrigerant from said first portion into said second portion during each on cycle to produce a lower temperature in the first compartment than in the second compartment, the time delay means including means forming a first chamber for the separation of gaseous and liquid refrigerant, means forming a second chamber into which said liquid refrigerant flows from the first chamber, means creating a back pressure of gaseous refrigerant from the first chamber forcing liquid refrigerant from the first chamber into the second chamber, said second chamber having an overflow for liquid refrigerant that is above the bottom of said second chamber flowing into said second portion of the evaporator.

2. A refrigerator, comprising: means forming a first compartment; means forming a second compartment; a continuous evaporator with refrigerant flow passages therein, the evaporator having a first portion in thermal contact with the first compartment for cooling the same and a second portion in thermal contact with the second compartment for cooling the same, the refrigerator operating in successive on and off cycles with refrigerant flowing through said passages, first into the first portion passages and then into the second portion passages; and time delay means for delaying the flow of liquid refrigerant from said first portion into said second portion during each on cycle to produce a lower temperature in the first compartment than in the second compartment, the time delay means including means forming a first chamber for the separation of gaseous and liquid refrigerant, means forming a second chamber into which said liquid refrigerant flo-ws from the first chamber, the gaseous refrigerant passage from the first chamber joining the liquid refrigerant passage from the second chamber at a point remote from said chambers and said gaseous refrigerant passage having means creating a back pressure of gaseous refrigerant from the first chamber forcing liquid refrigerant from the first chamber into the second chamber, said second chamber having an overflow for liquid refrigerant that is above the bottom of said second chamber flowing into said second portion of the evaporator.

3. The refrigerator of claim 2 wherein said back pressure creating means includes a series of restrictions in a gaseous refrigerant passage on the downstream side of said first chamber.

4. A refrigerator, comprising: means forming a first compartment; means forming a second compartment adjacent to the first compartment; a continuous, integral sheet evaporator with interconnected refrigerant flow passages therein, the evaporator having a first portion including a plurality of angularly arranged sections on a plurality of sides of the first compartment and a second portion extending from said first portion into the sec ond compartment, the refrigerator operating in successive on and off cycles with refrigerant flowing through said passages, first into the first portion passages and then into the second portion passages; and time delay means for delaying the flow of liquid refrigerant from said first portion into said second portion during each on cycle to produce a lower temperature in the first compartment than in the second compartment, the time delay means including means forming a first chamber for the separation of gaseous and liquid refrigerant, means forming a second chamber into which said liquid refrigerant flows from the first chamber, means creating a back pressure of gaseous refrigerant from the first chamber forcing liquid refrigerant from the first chamber into the second F chamber, said second chamber having an overflow for liquid refrigerant that is above the bottom of said second chamber flowing into said second portion of the evaporator.

5. A refrigerator, comprising: means forming a first compartment; means forming a second compartment adjacent to the first compartment; a continuous, integral, sheet evaporator with interconnected refrigerant flow passages therein, the evaporator having a first portion including a plurality of angularly arranged sections on a plurality of sides of the first compartment and a second portion extending from said first portion into the second compartment, the refrigerator operating in successive on and off cycles with refrigerant flowing through said passages, first into the first portion passages and then into the second portion passages; and time delay means for delaying the flow of liquid refrigerant from said first portion into said second portion during each on cycle to produce a lower temperature in the first compartment than in the second compartment, the time delay means including means forming a first chamber for the separation of gaseous and liquid refrigerant, means forming a second chamber into which said liquid refrigerant flows from the first chamber, the gaseous refrigerant passage from the first chamber joining the liquid refrigerant passage from the second chamber at a point remote from said chambers and said gaseous refrigerant passage having means creating a back pressure of gaseous refrigerant from the first chamber forcing liquid refrigerant from the first chamber into the second chamber, said second chaber having an overflow for liquid refrigerant that is above the bottom of said second chamber flowing into said second portion of the evaporator.

6. A refrigerator, comprising: means forming a first compartment; means forming a second compartment adjacant the first compartment; a continuous, integral, sheet evaporator with interconnected refrigerant flow cluding a plurality of angularly arranged sections on a plurality of sides of the first compartment and a second portion extending from said first portion into the second compartment, the refrigerator operating in successive on and off cycles with refrigerant flowing through said passages, first into the first portion passages and then into the second portion passages; a continuous electric heater Wire in thermal contact with said sheet for periodically defrosting the same; and time delay means for delaying the flow of liquid refrigerant from said first portion into said second ortion during each on cycle to produce a lower temperature in the first compartment than in the second compartment, the time delay means including means forming afirst chamber for the separation of gaseous and liquid refrigerant, means forming a second chamber into which said liquid refrigerant flows from the first chamber, the gaseous refrigerant passage from the first chamber joining the liquid refrigerant passage from the second chamber at a point remote from said chambers and said gaseous refrigerant passage having means creating a back pressure of gaseous refrigerant from the first chamber forcing liquid refrigerant from the first chamber into the second chamber, said second chamber having an overflow for liquid refrigerant that is above the bottom of said second chamber flowing into said second portion of the evaporator.

7. A refrigerator, comprising: means forming a first compartment; means forming a second compartment; :1 continuous evaporator with refrigerant flow passages therein, the evaporator having a first portion in thermal contact with the first compartment for cooling the same and a second portion in thermal contact with the second compartment for cooling the same, the refrigerator operating in successive on and ofi cycles with refrigerant flowing through said passages, first into the first portion passages and then into the second portion passages; and time delay means for delaying the flow of liquid refrigerant from said first portion into said second portion during each on cycle to produce a lower temperature in the first compartment than in the second compartment, the time delay means including means forming a first chamber for the separation of gaseous and liquid refrigerant, means forming a second chamber into which said liquid refrigerant flows from the first chamber and means creating a back pressure of gaseous refrigerant from the first chamber forcing liquid refrigerant from the first chamber into the second chamber.

References Cited in the file of this patent UNITED STATES PATENTS 2,133,954 Buchanan Oct 25, 1938 2,410,194 Baker Oct. 29, 1946 2,449,094 Wheeler Sept. 14, 1948 2,777,300 Palmer Jan. 15, 1957 2,795,113 Wurtz June 11, 1957

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