JP2007162961A - Evaporator for refrigerating machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely defrost an evaporator for refrigerating having various lengths at airflow upstream-side ends of plate fins. <P>SOLUTION: This evaporator for a refrigerating machine comprises a number of plate fins 27 stacked in a direction orthogonal to the airflow direction A, and a tube 28 penetrating a number of plate fins 27 in the stacking direction and allowing a low pressure-side refrigerant to flow therein, a number of plate fins 27 includes a first plate fin 30, and a second plate fin 31 having a projecting portion 31a projecting to the airflow upstream side with respect to an end face 30a at the airflow upstream side of the first plate fin 30, and the projecting portion 31a is provided with a defrosting tube 24 in which a high pressure-side refrigerant flows. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an evaporator for a refrigerator, and is suitable for use in a heat exchanger for cooling a refrigeration apparatus for a vehicle.

  Conventionally, in a plate fin type refrigerator evaporator in which a large number of plate fins are stacked in a direction perpendicular to the air flow direction, the air flow upstream end of the plate fins is alternately provided with a length for each plate. The upstream end portion of the flow is made uneven, thereby preventing condensed water from remaining at the upstream end portion of the air flow (see, for example, Patent Document 1).

  Specifically, the first plate fins and the second plate fins having a longer dimension in the air flow direction than the first plate fins are alternately stacked one by one, and the air flow upstream end of the second plate fins are arranged. It arrange | positions so that it may protrude rather than the air flow upstream edge part of a 1st plate fin.

  That is, by increasing the fin pitch between the plate fins at the upstream end of the air flow, the condensed water adhering to the upstream end of the air flow of the plate fin can be quickly dropped without remaining due to surface tension. It has become.

  In this prior art, a tube in which a refrigerant flows is passed through the first plate fin and the second plate fin in the stacking direction. The tube penetrates through a portion where the first plate fin and the second plate fin face each other. Therefore, the tube is not disposed in the protruding portion of the second plate fin that protrudes from the first plate fin.

  On the other hand, as shown in FIG. 10, what applied the evaporator for refrigerators of patent document 1 to the heat exchanger 10 for cooling of the refrigeration apparatus for vehicles is commercialized. In this prior art, a bypass passage 21 is provided that guides high-temperature and high-pressure refrigerant (hot gas) discharged from the compressor 11 to the heat exchanger 10 for cooling by bypassing the radiator 15.

And at the time of the defrost operation which defrosts the heat exchanger 10 for cooling, since the hot gas discharged from the compressor 11 is directly flowed to the heat exchanger 10 for cooling through the bypass flow path 21, it is hot The cooling heat exchanger 10 can be defrosted by the heat of the gas.
JP-A-4-236081

  However, in the prior art of FIG. 10, since the tube 28 is not disposed at the protruding portion of the second plate fin 31, the distance from the tube 28 to the end of the second plate fin 31 on the upstream side of the air flow A is It is longer than the distance from 28 to the end of the first plate fin 30 on the upstream side of the air flow A.

  For this reason, since the heat of hot gas is not easily transmitted to the end of the second plate fin 31 on the upstream side of the air flow A, the end of the second plate fin 31 on the upstream side of the air flow A is sufficiently defrosted. I can't.

  As a result, since ice accumulates at the end of the second plate fin 31 on the upstream side of the air flow A, the flow rate of the air flowing through the cooling heat exchanger 10 decreases, and the cooling heat exchanger 10 There is a problem that the heat exchange performance deteriorates.

  An object of this invention is to enable it to defrost reliably in the evaporator for refrigerators which attached the length to the air flow upstream edge part of a plate fin in view of the said point.

To achieve the above object, the present invention comprises a plurality of plate fins (27) stacked in a direction perpendicular to the air flow direction (A),
A plurality of plate fins (27) penetrating in the stacking direction, and a tube (28) through which the low-pressure refrigerant flows inside,
The plurality of plate fins (27) include a first plate fin (30) and a protrusion (31a) that protrudes upstream of the air flow upstream end surface (30a) of the first plate fin (30). A second plate fin (31) having
The protrusion (31a) is characterized in that a defrosting tube (24) through which the high-pressure side refrigerant flows is arranged.

  According to this, since the defrosting tube (24) through which the high-temperature high-pressure side refrigerant flows is arranged in the projecting portion (31a) of the second plate fin (31) that projects to the upstream side of the air flow, the high-pressure side refrigerant is The heat which has can be fully transmitted to the protrusion part (31a) of a 2nd plate fin (31).

  For this reason, the protrusion part (31a) of the 2nd plate fin (31) which protrudes to an air flow upstream can be defrosted reliably.

  Specifically, in the present invention, the defrosting tube (24) and the tube (28) are connected so that the high-pressure refrigerant passes through the defrosting tube (24) and then flows through the tube (28).

  According to this, since the high-temperature high-pressure refrigerant passes through the defrosting tube (24) and then flows through the tube (28), not only the protrusion (31a) of the second plate fin (31) but also a large number of plates. The entire fin (27) and the tube (28) can be defrosted.

  Further, since the high-pressure side refrigerant flows through the defrosting tube (24) before the tube (28), the high-pressure side refrigerant can flow through the defrosting tube (24) at the highest temperature.

  For this reason, it is compatible to surely defrost the protrusion (31a) of the second plate fin (31) and to defrost the entire plate fin (27) and the tube (28). it can.

  In the present invention, more specifically, the defrosting tube (24) may pass through the protrusion (31a) in the stacking direction.

  In the present invention, more specifically, the outer peripheral surface of the defrosting tube (24) may be in contact with the end surface (31b) on the protruding direction side of the protruding portion (31a).

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
The first embodiment of the present invention will be described below. FIG. 1 is an example in which the cooling heat exchanger 10 according to the first embodiment is applied to a vehicle refrigeration apparatus. In the vehicular refrigeration apparatus of the present embodiment, the compressor 11 that sucks and compresses refrigerant is rotationally driven by a vehicle travel engine (not shown) via a pulley 12, a belt, and the like.

  The compressor 11 may be a variable capacity compressor that can adjust the refrigerant discharge capacity by changing the discharge capacity, or a fixed capacity type compressor that adjusts the refrigerant discharge capacity by changing the operating rate of the compressor operation by switching the electromagnetic clutch. Any of the machines may be used. Further, if an electric compressor is used as the compressor 11, the refrigerant discharge capacity can be adjusted by adjusting the rotation speed of the electric motor.

  An oil separator 13 that separates lubricating oil in the refrigerant is disposed on the refrigerant discharge side of the compressor 11. The oil separator 13 is arranged to separate the oil in the refrigerant and return the oil to the refrigerant suction side of the compressor 12 via the decompression mechanism 14. In the present embodiment, a capillary tube is employed as the decompression mechanism 14.

  A radiator 15 is arranged on the refrigerant outflow side of the oil separator 13. The radiator 15 exchanges heat between the high-pressure side refrigerant of the refrigeration cycle, that is, the high-temperature high-pressure refrigerant (hot gas) discharged from the compressor 12 and the outside air (air outside the passenger compartment) blown by the cooling fan 16. Go and cool the hot gas.

  A receiver 17 is arranged on the downstream side of the refrigerant flow with respect to the radiator 15. The receiver 17 separates the refrigerant flowing out of the radiator 15 into a liquid phase refrigerant and a gas phase refrigerant and flows out the liquid phase refrigerant, and stores excess refrigerant as the liquid phase refrigerant.

  The liquid refrigerant flowing out of the receiver 17 is decompressed by the decompressor 18 and then flows into the cooling heat exchanger 10. That is, the low-pressure side refrigerant of the refrigeration cycle flows into the cooling heat exchanger 10. Air is blown to the cooling heat exchanger 10 as indicated by an arrow A by a blower fan 19.

  The refrigerant flowing through the cooling heat exchanger 10 absorbs heat from the blown air and evaporates, whereby the blown air is cooled. Air (cold air) cooled by the cooling heat exchanger 10 is blown out into a freezer (not shown).

  The refrigerant flowing out of the cooling heat exchanger 10 is separated into a gas phase refrigerant and a liquid phase refrigerant by the accumulator 20. The separated gas-phase refrigerant is supplied to the suction side of the compressor 11, and the liquid-phase refrigerant is stored in the accumulator 20.

  On the upstream side of the refrigerant flow of the radiator 15, a bypass passage 21 where the refrigerant flow branches is disposed. The bypass flow path 21 is a flow path that guides the hot gas discharged from the compressor 11 to the cooling heat exchanger 10 by bypassing the radiator 15.

  A defrost valve 22 is disposed in the bypass channel 21. The defrost valve 22 is an electromagnetic valve that switches between a case where hot gas is passed through the bypass passage 21 and a case where hot gas is not passed through the bypass passage 21, and is controlled to be opened and closed by an air conditioning electronic control unit (ECU) 23. The air-conditioning electronic control device 23 is constituted by a known microcomputer composed of a CPU, ROM, RAM, and the like and a peripheral circuit thereof as is well known.

  The hot gas flowing through the bypass channel 21 flows into the defrosting tube 24 (detailed later) of the cooling heat exchanger 10.

  A defrost release sensor 25 for detecting the refrigerant temperature is disposed on the downstream side of the refrigerant flow of the cooling heat exchanger 10. The detection signal from the defrost release sensor 25 is input to the air conditioning electronic control unit 23.

  The air conditioning electronic control device 23 is also provided with an operation signal from a defrosting switch 26 that is disposed on an air conditioning operation panel (not shown) and operated by a passenger.

  Next, the structure of the cooling heat exchanger 10 will be described with reference to FIG. FIG. 2 is a perspective view of the main part of the cooling heat exchanger 10, and the up, down, left and right arrows in FIG.

  The cooling heat exchanger 10 has a plate fin type heat exchange structure including rectangular plate fins 27 formed of a metal such as aluminum and tubes 28 through which a refrigerant flows.

  Specifically, a large number of plate fins 27 are stacked at a predetermined interval, and side plates 29 (FIG. 1) that form reinforcing members are disposed at both ends in the fin stacking direction.

  A tube insertion hole 27b through which the tube 28 penetrates is provided in the plate surface of the flat plate portion 27a of the plate fin 27, and a tube insertion hole (not shown) through which the tube 28 passes is also provided in the plate surface of the flat plate portion of the side plate 29.

  The tube 28 is inserted and fixed in a skewered manner into the tube insertion holes 27 b of the many plate fins 27 and the tube insertion holes of the side plates 29.

  U-shaped bent portions 28 a (FIG. 1) are formed at both ends of the tube 28 in the stacking direction of the plate fins 27. The refrigerant inlet portion 28b (FIG. 1) of the tube 28 is disposed on the air suction side of the cooling heat exchanger 10, and the refrigerant outlet portion 28c (FIG. 1) of the tube 28 is the air blowing side of the cooling heat exchanger 10. Is arranged.

  Note that the cooling heat exchanger 10 in this example is arranged so that the stacking direction of the plate fins 27 faces the vehicle left-right direction, and the air suction side faces the vehicle lower side. Therefore, the flow direction A of the air blown to the cooling heat exchanger 10 is directed from the vehicle lower side to the vehicle upper side.

  The multiple plate fins 27 are configured by alternately laminating the first plate fins 30 and the second plate fins 31 one by one. Here, the second plate fin 31 is formed so that the dimension in the air flow direction A is longer than the first plate fin 30 by a predetermined dimension L.

  The first and second plate fins 30 and 31 are arranged with their end faces aligned at the downstream side of the air flow (in this example, the vehicle upper side). For this reason, the end faces of the first and second plate fins 30 and 31 are uneven on the upstream side of the air flow (the vehicle lower side in this example).

  That is, a protruding portion 31 a that protrudes by a predetermined dimension L from the end surface 30 a on the upstream side of the air flow of the first plate fin 30 is formed at the end portion of the second plate fin 31 on the upstream side of the air flow.

  Thereby, on the end surface 31 b on the upstream side of the air flow of the second plate fin 31, the adjacent fins are not the first plate fins 30 but the second plate fins 31. For this reason, the fin pitch P <b> 1 on the end surface 31 b of the second plate fin 31 can be made larger than the fin pitch P <b> 2 between the first and second plate fins 30 and 31.

  Thereby, the condensed water adhering to the end surface 31b of the 2nd plate fin 31 falls rapidly, without remaining with surface tension.

  The defrosting tube 24 is inserted and fixed to the protrusion 31 a of the second plate fin 31 in a skewered manner. Therefore, the protrusion direction length L of the protrusion part 31a of the 2nd plate fin 31 is larger than the outer diameter D of a defrost piping.

  As shown in FIG. 1, one end of the defrosting tube 24 (the right end in FIG. 1) is connected to the bypass channel 21, and the other end of the defrosting tube 24 (the left end in FIG. 1) is the tube 28. Is connected to the refrigerant inlet portion 28b.

  Therefore, the hot gas flowing through the bypass passage 21 passes through the defrosting tube 24 from one end to the other end, and then flows through the tube 28 from the refrigerant inlet portion 28b toward the refrigerant outlet portion 28c. Yes.

  Next, the operation in the above configuration will be described. During the refrigeration operation, which is a normal operation state, the defrost valve 22 is closed, so that the entire amount of hot gas (high-temperature high-pressure refrigerant) discharged from the compressor 11 is cooled by the radiator 15 and then received by the receiver 17. It is separated into a liquid phase refrigerant and a gas phase refrigerant.

  The separated liquid phase refrigerant is decompressed by the decompressor 18 and then guided to the tube 28 of the cooling heat exchanger 10. The liquid refrigerant flowing through the tube 28 absorbs heat from the air blown by the blower fan 19 and evaporates. Thereby, since ventilation air is cooled and it blows off in the freezer which is not shown in figure, the inside of a freezer can be cooled.

  The refrigerant flowing out of the cooling heat exchanger 10 is separated into a gas phase refrigerant and a liquid phase refrigerant by the accumulator 20, and the separated gas phase refrigerant is sucked into the compressor 11.

  Here, since the cooling heat exchanger 10 is operated under a condition where the refrigerant evaporation temperature is lower than 0 ° C., frost adheres to the cooling heat exchanger 10 and the cooling performance deteriorates.

  Therefore, in the present embodiment, frost adhering to the cooling heat exchanger 10 is removed by the defrosting operation. This defrosting operation is started after a certain time (for example, 1 hour later) after the start of the freezing operation. In this example, the defrosting operation is also started when the defrosting switch 26 is turned on by the passenger.

  When the defrosting operation is started, the defrosting valve 22 is opened by the air conditioning electronic control unit 23. Thereby, the hot gas discharged from the compressor 11 flows through the bypass flow path 21 and flows into the defrosting tube 24 of the cooling heat exchanger 10.

  Since the defrosting tube 24 is inserted and fixed to the protruding portion 31a of the second plate fin 31, the frost attached to the protruding portion 31a of the second plate fin 31 can be reliably melted by the heat of the hot gas.

  Furthermore, in this embodiment, since the distance from the defrosting tube 24 to the end surface 31b in the air flow upstream of the 2nd plate fin 31 is shortened, the frost adhering to the end surface 31b of the 2nd plate fin 31 is ensured. Can be melted.

  The hot gas that has passed through the defrosting tube 24 flows in the tube 28 from the refrigerant inlet portion 28b toward the refrigerant outlet portion 28c. Thereby, the frost adhering to not only the protrusion part 31a of the 2nd plate fin 31 but many plate fins 27 whole and the tube 28 can be melt | dissolved with the heat which hot gas has.

  Here, since the hot gas flows through the defrosting tube 24 before the tube 28, the hot gas can flow through the defrosting tube 24 at the highest temperature.

  For this reason, it is possible to achieve both the defrosting of the protrusions 31 a and the end surfaces 31 b of the second plate fins 31 and the defrosting of the entire plate fins 27 and the tubes 28.

  This defrosting operation is ended when the outlet refrigerant temperature of the cooling heat exchanger 10 reaches a predetermined temperature. In this example, when the refrigerant temperature detected by the defrost release sensor 25 reaches + 3 ° C. or higher, the defrost valve 22 is closed to block the flow of hot gas to the bypass passage 21.

(Second Embodiment)
In the said 1st Embodiment, although the defrosting tube 24 is inserted and fixed to the protrusion part 31a of the 2nd plate fin 31 like a skewer, in this embodiment, as shown in FIG. The outer peripheral surface of the second plate fin 31 is fixed in contact with the end surface 31b on the upstream side of the air flow.

  Specifically, the defrosting is performed by extending the side plate 29 to the upstream side of the air flow with respect to the first embodiment and forming a tube insertion hole (not shown) through which the defrosting tube 24 penetrates in the extended portion. The outer peripheral surface of the tube 24 is fixed in contact with the end surface 31b of the second plate fin 31 on the upstream side of the air flow.

  In this embodiment, since the outer peripheral surface of the defrosting tube 24 is in contact with the end surface 31b of the second plate fin 31, the protrusion 31a and the end surface 31b of the second plate fin 31 are heated by the heat of the hot gas during the defrosting operation. The frost attached to the can be surely melted.

  Moreover, in this embodiment, since the defrosting tube 24 is not inserted in the protrusion part 31a of the 2nd plate fin 31, the protrusion direction length L of the protrusion part 31a of the 2nd plate fin 31 is not necessarily the outer diameter D of defrost piping. There is no need to make it larger. For this reason, the design freedom of the protrusion direction length L of the protrusion part 31a of the 2nd plate fin 31 can be improved.

(Other embodiments)
In each of the above embodiments, the cooling heat exchanger 10 is arranged so that the air suction side faces the vehicle lower side, but is not limited thereto, and the air suction side is the vehicle upper side, or You may arrange | position so that it may face a horizontal direction side.

  In this case, the protruding portion 31a of the second plate fin 31 is formed not only on the air suction side of the cooling heat exchanger 10 but also on the vehicle lower side end portion, so that the fin pitch at the vehicle lower side end portion is increased. It is good to do.

  Thereby, even if condensed water collects in the vehicle lower side end part of the heat exchanger 10 for cooling by gravity, it can prevent that the water droplet of condensed water remains with the protrusion part 31a of a vehicle lower side edge part.

  Further, in each of the above embodiments, the first plate fins 30 and the second plate fins 31 are alternately stacked one by one. However, the present invention is not limited to this, for example, between the second plate fins 31. Alternatively, two first plate fins 30 may be disposed.

1 is an overall configuration diagram of a vehicular refrigeration apparatus according to a first embodiment of the present invention. It is a principal part perspective view of the heat exchanger for cooling by 1st Embodiment of this invention. It is a principal part perspective view of the heat exchanger for cooling by 2nd Embodiment of this invention. It is a whole block diagram of the refrigeration apparatus for vehicles by a prior art.

Explanation of symbols

24 ... defrosting tube, 27 ... many plate fins, 28 ... tube,
30 ... 1st plate fin, 30a ... End surface, 31 ... 2nd plate fin,
31a ... Projection, 31b ... End face, A ... Air flow direction

Claims (4)

A number of plate fins (27) stacked in a direction perpendicular to the air flow direction (A);
A tube (28) that penetrates the multiple plate fins (27) in the stacking direction and in which the low-pressure side refrigerant flows;
The plurality of plate fins (27) protrude from the first plate fin (30) and the end surface (30a) of the first plate fin (30) on the upstream side of the air flow toward the upstream side of the air flow. A second plate fin (31) having a portion (31a),
The evaporator for a refrigerator, wherein a defrosting tube (24) through which a high-pressure side refrigerant flows is arranged in the protruding portion (31a). The defrosting tube (24) and the tube (28) are connected so that the high-pressure side refrigerant flows through the defrosting tube (24) and then flows through the tube (28). The evaporator for refrigerators of Claim 1. The evaporator for refrigerating machines according to claim 1 or 2, wherein the defrosting tube (24) penetrates the protrusion (31a) in the stacking direction. The evaporator for refrigerating machines according to claim 1 or 2, wherein an outer peripheral surface of the defrosting tube (24) is in contact with an end surface (31b) of the protruding portion (31a) on the protruding direction side. vessel.

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