JPH0442712Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a refrigerator equipped with a temperature switch that cuts off electricity to a defrosting heater.

(b) Conventional technology Publication of Utility Model Publication No. 58-7272 (F25D29/00) states,
A configuration is shown in which a plate fin type cooler is provided with a defrosting heater on the lower surface and a heat-responsive switch covered with a vinyl tube on the outer surface of the tube plate to prevent the heater from overheating, and is arranged in the cold air passage. ing.

(c) Problems to be solved by the invention According to the above-mentioned conventional technology, since one end of the defrosting heater protrudes outward from the tube plate, radiant heat from the defrosting heater is not absorbed during defrosting operation. This heat is transmitted directly to the frost covering the thermally responsive switch, and is also heated by the convection air generated by the defrosting heater.
For this reason, even if the heat-responsive switch is covered with a material such as vinyl tube that has poor thermal conductivity (in other words, good heat radiation), the amount of frost near the outside surface of the tube sheet will be higher than that of the cooler. As a result, when there is a large amount of frost, the defrost heater is not energized even though there is residual frost in the cooler. A problem occurred that caused the connection to be blocked.

(d) Means for solving the problem In order to solve the above problem, this proposal includes a plate-fin type cooler 7 having a pair of tube plates 21 and 22 on both left and right sides, and A defrosting heater 8 that is placed directly below and is energized during defrosting operation is housed in the cold air passage 6, and a refrigerant that protrudes laterally from the outer surface of one of the tube sheets or from this tube sheet. A temperature switch for defrosting recovery that cuts off the power supply to the defrosting heater is provided in a part of the tube, and the temperature switch is located below the temperature switch and the defrosting heater 8.
A pair of left and right tube plates located directly above both ends of the tube plates 21 and 22, projecting laterally from the lower ends of the tube plates 21 and 22, respectively, and slanting low toward the tip thereof, and having the tip close to the side wall surface of the cold air passage. Projecting piece 29, 3
To provide a refrigerator 1 provided with 0.

(E) Function During defrosting operation, the protruding piece 30 acts as a full plate to cut off the radiant heat directed from the defrosting heater 8 toward the temperature switch 24 and reduce the thermal influence of the defrosting heater 8 on the temperature switch 24, and the temperature switch In addition to acting as a directing plate that directs convective air below 24 toward the air inlet surface of the cooler 7, both protruding pieces 29 and 30 prevent the shot cycle of cold air around both tube plates 20 and 21 during cooling operation. Furthermore, when the defrosting heater 8 is energized, it acts as a frost receiving plate that receives frost from both tube sheets 21, 22 and a portion of the refrigerant tube 23 protruding laterally from the tube sheets.

(f) Examples Embodiments of the present invention will be described below based on the drawings.

Reference numeral 1 denotes a reach-in type refrigerator whose main body is composed of a heat insulating wall 2 with an opening 3 for storing and taking out products on the front, and a transparent door 4 on the front that can freely open and close the opening 3. Further, by disposing a partition plate 5 at an appropriate distance from the inner surface of the heat insulating wall 2, a plate fin type cooler 7 is provided in the back area 6A, and is located directly below this cooler and is energized during defrosting operation. A cold air passage 6 in which a tubular defrosting heater 8 and a blower fin 9 are housed, a storage chamber 11 in which a plurality of shelves 10 are housed, and air outlets facing each other along the inside of both upper and lower edges of the opening 3; Both suction ports 12, 13
As shown by the arrow in FIG. 3, the cold air that has been heat exchanged by the cooler 7 is forcedly circulated by the blower fan 9, so that the air is supplied to the inside of the opening 3, that is, to the front of the storage chamber 11. This storage room 11 is cooled by forming a curtain. Reference numeral 14 denotes a fluorescent lamp disposed between the air outlet and suction ports 12 and 13, which is orthogonal to each shelf 10 and which is connected to the storage chamber 11.
Prove the whole range of. Reference numeral 15 denotes a machine room formed below the heat insulating wall 2, which includes a refrigerant compressor 16 and a condenser 17, which constitute a refrigeration cycle together with the cooler 7;
In addition to housing the blower fin 18, a drain tray 19 is also housed therein.

The cooler 7 is made of a thin aluminum plate and has a large number of fins 20 arranged in parallel at appropriate intervals.
, a pair of left and right metal tube plates 21 and 22 arranged in parallel on both the left and right sides of the fins, and a large number of refrigerant tubes 23 penetrating orthogonally to each of the fins 20 and both tube plates 21 and 22, Its lower surface serves as an air inlet surface and its upper surface serves as an air outlet surface, and as it is attached to the back wall 2A of the heat insulating wall 2, a space 6B,
Forms 6C. 24 is bimetal switch 24
A temperature switch for defrosting recovery, which is attached to the outer surface of one tube plate 22 as shown in FIG. During defrosting operation, the thermal influence from the defrosting heater 8 increases, and when the preset temperature is reached, the bimetal switch 24A opens as shown in FIG. Cut off. In Fig. 4, DT is the defrost timer, DTa and DTb are the normally open and normally closed contacts of this defrost timer, and the normally open contact is
A thermostat 25 that detects the temperature of the storage room 11 and a compressor electromagnetic switch 26 are connected in series to the DTa, and a blower fan 9 for circulating cold air is connected in parallel to the thermostat and the compressor electromagnetic switch 26. Temperature switch 24 is connected to the normally closed contact DTb.
and a defrosting heater 8 are connected in series. Further, the defrosting heater 8 is longer in length than the width of the cooler 7, and has a seal portion 27 formed at one end of the defrost heater 8 in which the connecting portion to the lead wire 26A is coated with rubber or resin. This defrosting heater 8 is supported by a support 28 provided on the bottom wall 2B of the heat insulating wall 2 in order to melt the frost attached to the cooler 7 with its radiant heat. It is also possible to have a structure in which both of them are directly attached to the lower surface of the cooler 7 in order to thaw the frost.

Reference numerals 29 and 30 denote a pair of left and right protruding pieces that are attached to the tube sheets 21 and 22 and protrude laterally from the lower ends of the tube sheets, respectively, and are sloped low in the tip direction. 2 left and right side walls 2C, 2
A gap 31 is formed close to the inner surface of D,
A space 6 is provided between the cooler 7 and the side walls 2B and 2C.
The upper surfaces of tubes B and 6C are closed to prevent the shot cycle of cold air around both tube sheets 21 and 22. Among the two protruding pieces 29 and 30, one protruding piece 30 is located directly below the temperature switch 24 and directly above the seal portion 27 of the defrosting heater 8, and a portion of the protruding piece 30 is located directly below the temperature switch 24. It is cut out to form a guide path 32, and the compressor 1 is connected from the cooler 7 to this guide path.
6 is passed through the suction pipe 33.

According to such a configuration, during a defrosting operation in which the refrigerant supply to the cooler 7 and the operation of the blower fan 9 are stopped, and the defrosting heater 8 is energized, the radiant heat from the defrosting heater 8 and this radiant heat are As a result, the frost adhering to the cooler 7 is gradually melted by the heat conduction of the cooler 7 itself, which has risen in temperature, while the air below the back area 6A, which is convected by the heating effect of the radiant heat,
A part of it is from the gap 31 and the guide path 32 to the space 6C
to melt the frost adhering to the outer surface of the tube plate 22, the curved portion 23A, and the temperature switch 24 of the cooler 7. Note that the heated convection air also enters the space 6B to thaw frost adhering to the outer surface of the tube sheet 21 and the curved portion 23A. When the defrosting operation progresses and the air temperature in the space 6C rises to a predetermined temperature, the temperature switch 2
The bimetal switch 24A of No. 4 is opened, and power supply to the defrosting heater 8 is cut off.

In this defrosting operation, the protruding piece 30 functions as a buffle plate to reduce the thermal influence of the defrosting heater 8 on the temperature switch 24, and this function slows down the time until the temperature switch 24 operates, that is, the defrosting It is possible to eliminate residual frost on the cooler 7 by increasing the energization time of the frost heater 8, and also acts as a directing plate that directs convective air below the space 6C toward the air inlet surface of the cooler 7. , Due to this action, the amount of defrosting heat of the cooler 7 can be increased,
Also, it functions as a dew receiving plate that receives dew from the temperature switch 24, the curved portion 23A, and the tube plate 22, and by this function, the protruding piece 30 drains dew from the gap 31 along its slope.
It is possible to avoid water leakage from the seal portion 27 of the defrosting heater 8 and improve the durability of the defrosting heater 8.

Furthermore, during cooling operation, since the air below both spaces 6B and 6C can be directed toward the air inlet surface of cooler 7 by both protruding pieces 29 and 30, most of the air passes through cooler 7 and is cooled. As a result, short cycles can be prevented and heat exchange between cold air can be improved.

(g) Effects of the invention According to the invention described above, during defrosting operation, the protruding piece can reduce the thermal effect of the defrost heater on the temperature switch and lengthen the energization time of the defrost heater. In addition, the convective air below the temperature switch can be directed toward the air inlet surface of the cooler, and as a result, the remaining frost on the cooler can be eliminated and the heat of the defrosting heater can be used effectively. Furthermore, during defrosting operation, the protruding piece receives frost from both tube sheets and a part of the refrigerant pipe that protrudes laterally from below the tube sheet, and moves the frost downward from the tip close to the side wall surface along the slope. For guidance purposes,
Water leakage due to dew on both ends of the defrosting heater can be avoided.
There is also the effect of improving the durability of the defrosting heater.
Further, during cooling operation, the two protruding pieces prevent the short cycle of cold air around both tube sheets, and at the same time, the flow rate of heat exchange of cold air increases, thereby improving the cooling effect.

[Brief explanation of the drawing]

The drawings show an embodiment of the refrigerator according to the present invention, and FIG. 1 is a longitudinal sectional view of the main part, FIG. 2 is a perspective view of the main part, FIG. 3 is a longitudinal sectional view of the whole refrigerator, and FIG. 4 is an electric circuit. 6...Cold air passage, 7...Cooler, 8...Defrost heater, 9...Blower fan, 21, 22...Tube plate,
23...refrigerant pipe, 24...temperature switch, 29,
30...Protruding piece.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A plate-fin type cooler with a pair of tube plates on both left and right sides, and a defrosting heater that is placed directly below this cooler and is energized during defrosting operation. A defrost return unit that is housed in the cold air passage and cuts off electricity to the defrost heater in a part of the refrigerant pipe that protrudes laterally from the outer surface of one of the tube sheets or from this tube sheet. A temperature switch is provided, located below the temperature switch and directly above both ends of the defrosting heater, protrudes laterally from the lower ends of both tube plates, and slopes low toward the tip thereof, A refrigerator comprising a pair of left and right protruding pieces whose tips are close to the side wall surface of the cold air passage. 2. The refrigerator according to claim 1, wherein the protruding piece is sloped downwardly toward the distal end.