JP2002048459A - Refrigeration unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the scattering of ice from an evaporator when a refrigeration unit is operated for defrosting. SOLUTION: In this refrigeration unit, a defrosting circuit is provided for removing ice adhering to an evaporator 7 positioned in a freezing chamber. The defrosting circuit first supplies a high-temperature refrigerant discharged from a compressor 3 to a heater 12 for a drain pan which receives ice falling from the evaporator 7 through a defrosting solenoid valve 11 and a defrosting pipeline 20 and then defrosts the evaporator 7 by supplying the refrigerant to a defrosting refrigerant passage provided in the evaporator 7 by means of a defrosting distributor 130. The distributor 130 is positioned separately from a refrigerant distributor 13 for refrigerating operation and is set to make the high-temperature refrigerant to abundantly flow to the freezing chamber side of the evaporator 7. Consequently, the ice adhering to the evaporator 7 starts to melt on the freezing chamber side and falls to the depth side of the evaporator 7. Therefore, the ice hardly scatters in the freezing chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus, and more particularly to a refrigerating apparatus having a so-called hot gas bypass type defrost circuit for use in a freezer for land transportation such as a refrigerating vehicle.

[0002]

2. Description of the Related Art A refrigerating apparatus is generally known in which a gaseous high-temperature refrigerant compressed by a compressor is condensed by a condenser, evaporated by an evaporator disposed in the freezer, and cooled by the heat of vaporization of the refrigerant. In such a refrigerator,
There is a problem that water in the air in the freezer freezes on the heat exchanger of the evaporator, and the heat exchange efficiency of the heat exchanger is reduced. In order to prevent the reduction of the heat exchange efficiency, the gaseous high-temperature refrigerant at the compressor outlet is supplied directly to the evaporator by bypassing the condenser, thereby melting the ice attached to the evaporator heat exchanger. A refrigeration system having a hot gas bypass type defrost circuit has been devised.

FIG. 4 is a cross-sectional view of a condenser / evaporator unit of a refrigeration system having a conventional defrost circuit of this type, and FIG. 5 is a schematic circuit diagram thereof. As shown in FIG. 4, the condenser 4 and the evaporator 7
Are housed in a common housing,
An evaporator unit 100 is formed. Further, a heat insulating wall 300 made of a heat insulating material is formed between the condenser 4 and the evaporator 7 disposed in the housing of the condenser / evaporator unit 100 to thermally connect the high-temperature condenser section 1 and the low-temperature evaporator section 2 to each other. Is shut off. In the evaporator section 2, an evaporator fan 50 and an evaporator 7 are arranged below the evaporator fan 50. Further, the evaporator section 2 is formed with an air inlet opening 60 and an outlet opening 70 facing the inside of the freezer. The air in the freezer is sucked from the inlet opening 60 by the fan 50, and the heat exchanger of the evaporator 7 is removed. It is cooled and discharged from the air outlet 70 into the freezer. In the example of FIG. 4, the evaporator 7 is inclined so that the lower surface of the evaporator 7 faces the air inlet opening 60 in order to reduce the inflow resistance of air from the air inlet opening to the evaporator. A defrost tube 20b that melts the ice frozen on the evaporator lower part 30 at the time of the defrost operation is disposed directly below the evaporator 7. Reference numeral 40 denotes a drain pan that receives water droplets and ice falling from the evaporator during the defrost operation and prevents water and ice from entering the freezer. On the drain pan 40, a drain pan heater 12 for melting the ice dropped on the drain pan is provided.

[0005] As shown in FIG. 5, a refrigerant compressor 3 driven by, for example, an internal combustion engine, an electric motor or the like is arranged at a place different from the condenser / evaporator unit 100. A condenser inlet solenoid valve 10 is provided in a discharge pipe 14 of the compressor 3, and a defrost solenoid valve 11 is provided from a branch point 20 a of the pipe 14 on the upstream side of the solenoid valve 10.
The defrost piping 20 is branched through.

[0005] Refrigeration operation of unit 100 (normal operation)
At this time, the defrost solenoid valve 11 is closed and the condenser inlet solenoid valve 10 is opened. Thereby, the high-temperature gaseous refrigerant discharged from the compressor 3 flows into the air-cooled or water-cooled condenser 4 through the discharge pipe 14 and the solenoid valve 10.
The refrigerant cooled and liquefied by the condenser 4 passes through the receiver 5 and the dryer 6, passes through the refrigerant pipe 15 penetrating the heat insulating wall 300, is decompressed by the expansion valve 9, and flows into the evaporator 7. The evaporator 7 has a configuration in which a plurality of heat exchangers (for example, a plurality of evaporator coils) are arranged.
The refrigerant flowing from the expansion valve 9 flows into each heat exchanger of the evaporator 7 through the refrigerant distributor 13 which controls the distribution of the refrigerant flow to each coil of the evaporator, and flows in from the air inlet of the evaporator section 2 (FIG. 4). Evaporates by taking the heat of vaporization from the air in the freezer. The low-temperature gaseous refrigerant vaporized by the evaporator 7 passes through the evaporator outlet pipe 16 and the accumulator 8 and is sucked into the compressor 3 from the compressor inlet refrigerant pipe 17.

On the other hand, when a defrost operation for melting ice frozen on the evaporator 7 is performed, the condenser inlet solenoid valve 10 on the compressor refrigerant discharge pipe 14 is closed and the defrost solenoid valve 11 is opened. Is done. In this case, the high temperature gaseous refrigerant discharged from the compressor 3 is first supplied from the defrost solenoid valve 11 to the defrost tube 20b below the evaporator 7 through the defrost pipe 20, and melts the ice attached to the evaporator 7 to melt the evaporator 7. After being separated from the drain pan 40, it is supplied to the drain pan heater 12 arranged in the drain pan 40 (FIG. 1). The refrigerant after the ice is melted by the drain pan heater 12 is supplied to the refrigerant distributor 13 and supplied to the evaporator coil of the evaporator 7. The refrigerant gas that has heated the coil of the evaporator 7 and melted the attached ice is then sucked into the compressor 3 through the evaporator outlet pipe 16, the accumulator 8, and the refrigerant inlet pipe 17 in the same manner as in the freezing operation. That is, in the refrigerating apparatus of FIG. 5, the defrost solenoid valve 11 and the defrost pipe 2
0b, defrost tube 20b, drain pan heater 1
A defrost circuit is formed by the components of the refrigerant distributor 2 and the refrigerant distributor 13.

[0007]

In the above-described defrost circuit of the conventional refrigeration system, the defrost tube 20b causes the evaporator 7 to be directly below the evaporator 7 during the defrost operation.
The ice adhering to the melts and separates from the evaporator coil. This ice falls into the drain pan 40 and is completely melted by the drain pan heater 12, so that the defrost effect of the coil by the defrost tube 20b is considerably increased.

In the refrigerating apparatus shown in FIG. 4, however, the high-temperature gaseous refrigerant is first supplied to the evaporator coil after passing through the defrost tube 20b and the drain pan heater 12, so that the temperature of the refrigerant supplied to the evaporator coil decreases. In addition, the defrost effect of the evaporator coil itself is relatively low, and it may be difficult to effectively melt and peel off the ice attached to the upper part of the evaporator.

When the defrost tube 20b is mounted below the evaporator 7, the size of the entire evaporator is increased, so that it becomes difficult to mount the evaporator 7 in the housing. In addition, as shown in FIG. 4, when the evaporator 7 is arranged to be inclined with respect to the axis of the evaporator fan 50, the flow rate of the air passing through the evaporator 7 becomes the freezer side (the air inlet opening 60 side).
The depth side (the heat insulating wall 300 side, that is, the side far from the opening 60) is larger. For this reason, the refrigerant distributor 13
Is set to distribute the refrigerant so that the refrigerant flow rate of the coil on the depth side of the evaporator is greater than the refrigerant flow rate of the coil on the freezer side so as to be optimal for this air flow rate distribution. However, in the defrost circuit of FIG. 5, since the high-temperature refrigerant at the time of defrost is supplied to each coil of the evaporator 7 through the refrigerant distributor 13, it is supplied to the coil on the depth side of the evaporator as in the case of the refrigeration operation. The flow rate of the high-temperature refrigerant is higher than the flow rate of the high-temperature refrigerant supplied to the freezer-side coil. For this reason, when the defrost operation is started, ice frozen at the lower part of the coil is melted from the coil part on the depth side and peels off from the coil. In this case, since the ice frozen at the lower part of the coil forms a bridge and forms an integral ice block, if the ice on the depth side starts to be separated from the coil on the depth side before the coil on the freezer side, the ice block may fall. The ice block rotates around the freezer-side coil attachment portion that has not yet been peeled off, and does not fall onto the drain pan 40 below, so that the air inlet opening of the housing (FIG.
From 60), there is a problem that it is easy to fly into the freezer.

In view of the above-mentioned problems of the prior art, the present invention makes it easy to mount the evaporator on the housing, improves the defrost effect of the heat exchanger of the evaporator, and scatters ice into the freezer during defrost operation. It is an object of the present invention to provide a refrigeration apparatus capable of preventing the occurrence of the refrigeration.

[0011]

According to the first aspect of the present invention, there is provided an evaporator having a plurality of heat exchangers, the evaporator being disposed in a freezer, and containing the evaporator and passing air in the freezer through the evaporator. A refrigerating apparatus comprising: a housing having an opening through which the refrigerant flows, and a hot gas bypass type defrost circuit that supplies high-temperature refrigerant discharged from a compressor to the evaporator to melt ice attached to the evaporator, further comprising: A refrigerating operation distributor that distributes a low-temperature refrigerant supplied to the evaporator to the heat exchangers during the refrigeration operation, and a high-temperature refrigerant supplied to the evaporator from the defrost circuit during the defrost operation to the heat exchangers. And a defrost distributor separate from the refrigerating operation distributor, which distributes the refrigerant to the provided defrost refrigerant passage. The lost distributor has a flow rate of a high-temperature refrigerant flowing in a defrost refrigerant passage of a heat exchanger disposed on a side close to the housing opening of an evaporator, and a defrost refrigerant of a heat exchanger disposed on a side far from the housing opening. A refrigerating device is provided that is set to be higher than a flow rate of a high-temperature refrigerant flowing in a passage.

That is, according to the first aspect of the present invention, the high-temperature refrigerant flowing through the defrost refrigerant passage of the heat exchanger near the housing opening (ie, the freezer side) during the defrost operation is separate from the refrigerant distributor used during the refrigeration operation. A defrost distributor for distributing the flow rate of the high-temperature refrigerant such that the flow rate of the high-temperature refrigerant flowing through the defrost refrigerant passage of the heat exchanger farther from the housing opening is provided. For this reason, when the defrost operation is started, a large amount of high-temperature refrigerant is supplied to the heat exchanger on the freezer side, and ice attached to the heat exchanger on the freezer side adheres to the heat exchanger on the side (depth side) far from the housing opening. Melts and peels faster than ice.
For this reason, when the ice blocks are separated from the heat exchanger and fall, the rotation is likely to occur around the portion attached to the heat exchanger on the depth side, which is opposite to the conventional case, and the ice blocks fall to the side far from the housing opening. I will be. For this reason, the ice blocks separated from the heat exchanger surely fall onto the drain pan and are prevented from scattering into the freezer.

According to the second aspect of the present invention, furthermore, a drain pan disposed below the evaporator in the housing and receiving ice falling from the evaporator during the defrost operation, and the ice dropped into the drain pan during the defrost operation. A refrigerating apparatus according to claim 1, further comprising a drain pan heater configured to heat and melt using a high-temperature refrigerant, wherein the drain pan heater is disposed upstream of the defrost distributor in a high-temperature refrigerant flow direction on the defrost circuit. Provided.

That is, in the second aspect of the invention, the drain pan below the evaporator is provided with a drain pan heater, and the high-temperature refrigerant from the compressor is first supplied to the drain pan heater. For this reason, the refrigerant having the highest temperature is supplied to the drain pan heater, and the ice that has fallen into the drain pan is reliably melted into water and discharged out of the refrigerator.

According to the third aspect of the invention, the defrost distributor includes a refrigerant circuit that supplies a part of the high-temperature refrigerant supplied from the defrost circuit to the refrigeration distributor during the defrost operation. Further, a refrigeration apparatus according to claim 1 or 2 is provided. That is, in the third aspect of the present invention, a part of the high-temperature refrigerant gas supplied to the defrost refrigerant passage of the heat exchanger during the defrost operation is supplied to the refrigerating operation distributor. For this reason, a part of the sufficiently high-temperature refrigerant gas at the drain pan outlet directly passes through each heat exchanger of the evaporator, and the defrost effect of the heat exchanger itself is greatly improved.

According to the fourth aspect of the present invention, the refrigerant circuit further includes a check valve for preventing a flow of the refrigerant from the refrigerating operation distributor to the defrost distributor. Is provided. That is, in the invention of claim 4, since the check valve for preventing the flow of the refrigerant from the distributor for refrigeration operation to the distributor for defrost is provided, a part of the low-temperature refrigerant is distributed during the refrigeration operation. From flowing into the defrost circuit to prevent the cooling capacity of the evaporator from being reduced.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a circuit diagram similar to FIG. 5, showing a first embodiment of the present invention. 1, the same reference numerals as those in FIG. 5 denote the same elements as those in FIG. In the present embodiment, the refrigerant composed of the pipe 14, the inlet solenoid valve 10, the condenser 4, the receiver 5, the dryer 6, the expansion valve 9, the refrigerating operation distributor 13, the evaporator 7, the pipe 16, the accumulator 8, and the refrigerant inlet pipe 17 is used. The refrigeration circuit has the same configuration as that of FIG.

However, in this embodiment, the defrost circuit branches from the branch point 20a of the pipe 14 via the defrost solenoid valve 11 as in FIG. 5, but the subsequent configuration is different from the conventional example in FIG. I have. That is, in the present embodiment, the defrost tube 20b is not provided in the lower portion 30 of the evaporator 7, and instead, the evaporator 7 includes a plurality of refrigerant passages 71 for defrost extending upward from below along each heat exchanger. Defrost refrigerant passage 71
5 is provided with a defrost distributor 130 for distributing the high-temperature refrigerant during the defrost operation. The outlet pipe 72 of each defrost refrigerant passage 71 is
The junction 72a is connected to the evaporator outlet pipe 16 of the refrigeration circuit.

FIG. 2 is a circuit diagram showing a capacitor according to the present embodiment.
The sectional view of the evaporator unit 100 is shown. In the present embodiment, except that the defrost tube 30 is not provided in the evaporator 7 and that the defrost refrigerant passage 71 extends in the evaporator 7 along each heat exchanger, Evaporator unit 10
0 is substantially the same.

As shown in FIG. 1, in this embodiment, a defrost pipe 20 branched from the compressor discharge pipe 14 is
Unlike the case 1, the drain pan heater 12 is first connected, and the defrost distributor 130 is connected to the drain pan heater 12 outlet. Also in the present embodiment, the compressor 3
The defrosting operation is started by closing the condenser inlet electromagnetic valve 10 and opening the defrosting electromagnetic valve 11 during the operation. Thereby, the high-temperature gaseous refrigerant discharged from the compressor 3 flows into the defrost pipe 20, but in the present embodiment, the highest-temperature refrigerant discharged from the compressor 3 is directly supplied to the drain pan heater 12. Is done. Then, the drain pan 40 is
The refrigerant after melting the ice that has fallen into FIG. 1 flows into the defrost distributor 130.

As described above, the defrost distributor 130
Is for distributing the high-temperature refrigerant gas to the defrost refrigerant passage 71 disposed along each heat exchanger (evaporator coil) in the evaporator 7. In the present embodiment, the defrost distributor 130 is Contrary to the refrigerating operation distributor 13, the flow rate of the high-temperature refrigerant flowing through the defrost refrigerant passage 71 provided in the evaporator coil on the side (freezer side) closer to the air inlet opening 60 (FIG. 2) of the evaporator 7 is opened. The distribution of the flow rate of the high-temperature refrigerant to each defrost refrigerant passage is set so as to be larger than the flow rate of the high-temperature refrigerant flowing in the defrost refrigerant passage 71 provided on the evaporator coil farther from the side (depth side).

As a result, when the defrost operation is started, the ice adhering to the evaporator coil to form an integrated ice block is first melted and separated from the freezer side, so that the unseparated depth side The ice block rotates and drops in a direction away from the air inlet opening with the portion where the water is adhered as a fulcrum. For this reason, the ice falling from the evaporator during the defrost operation surely falls into the drain pan without scattering from the opening 60 into the freezer, is melted by the drain pan heater 12, and is discharged out of the freezer.

In this embodiment as well, the refrigerant after defrosting the evaporator 7 passes through the outlet pipe 72, flows into the evaporator outlet pipe 16 from the junction 72a, and is supplied to the compressor 3 through the accumulator 8. You.
FIG. 3 is a circuit diagram showing an embodiment different from FIG. 1 of the present invention. 3, the same reference numerals as those in FIG. 1 represent the same elements as those in FIG.

The present embodiment is different from the embodiment shown in FIG. 1 only in that a defrost distributor 150 different from that in FIG. 1 is used, and a part of the high-temperature refrigerant is supplied from the defrost distributor 150 to the refrigerating operation distributor 13. It is different from the form. That is, the defrost distributor 150 according to the present embodiment, as in the case of FIG. 1, converts the high-temperature refrigerant that has passed through the drain pan heater 12 into a refrigerant flow flowing through the defrost refrigerant passage disposed on the freezer side of the evaporator 7 in the depth direction. The refrigerant is distributed so as to be larger than the flow rate of the refrigerant flowing through the disposed defrosting refrigerant passage, and is configured so that a part of the refrigerant flowing from the drain pan heater 12 is further supplied to the refrigerant distributor 13 for refrigeration operation. Thus, in the present embodiment, a part of the high-temperature refrigerant is directly supplied from the drain pan heater 12 to the evaporator coil during the defrost operation. The temperature of the refrigerant that has passed through the drain pan heater 12 decreases less than the refrigerant that has passed through the defrost tube 12 in the prior art shown in FIG. Therefore, in this embodiment, a relatively high-temperature refrigerant is directly supplied to the evaporator coil, and the defrost effect of the evaporator coil itself can be further improved in addition to the embodiment of FIG.

In the present embodiment, in order to prevent the low-temperature refrigerant supplied to the refrigerating operation distributor 13 during the refrigerating operation from flowing into the defrost distributor 130 and lowering the cooling capacity of the evaporator, the refrigerant for the refrigerating operation is reduced. A check valve 155 that allows only the flow of the refrigerant from the defrost distributor 150 to the refrigeration distributor 13 is provided on a pipe 152 that connects the distributor 13 and the defrost distributor 150.

[0026]

According to the invention described in each of the claims, it is not necessary to provide a defrost tube in the evaporator of the refrigeration system, so that the evaporator can be easily attached to the housing, and the evaporator can be easily operated during the defrost operation. The effect that the ice which fell from the evaporator can be prevented from scattering in a freezer is acquired.

According to the third and fourth aspects of the present invention,
In addition to the above-mentioned common effects, there is an effect that the defrost effect of the evaporator itself during the defrost operation can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a refrigeration circuit of one embodiment of a refrigeration apparatus of the present invention.

FIG. 2 is a sectional view showing a schematic configuration of a condenser / evaporator unit of the refrigeration apparatus of the present invention.

FIG. 3 is a diagram illustrating a refrigeration circuit of an embodiment different from FIG. 1 of the refrigeration apparatus of the present invention.

FIG. 4 is a cross-sectional view illustrating a schematic configuration of a condenser evaporator unit of a conventional refrigeration apparatus.

FIG. 5 is a diagram illustrating an example of a refrigeration circuit of a conventional refrigeration apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 ... Compressor 4 ... Condenser 7 ... Evaporator 12 ... Drain pan heater 13 ... Refrigeration operation distributor 71 ... Defrost refrigerant passage 100 ... Condenser evaporator unit 130,150 ... Defrost distributor

Claims (4)

[Claims] 1. An evaporator having a plurality of heat exchangers disposed in a freezer, a housing containing the evaporator and having an opening through which air in the freezer flows through the evaporator, and a high temperature discharged from the compressor. A hot gas bypass type defrost circuit that supplies a refrigerant to the evaporator to melt ice attached to the evaporator, further comprising a low-temperature refrigerant supplied to the evaporator during a refrigeration operation. A refrigerating operation distributor that distributes the refrigerant to each heat exchanger; and a refrigerating operation distributor that distributes a high-temperature refrigerant supplied from the defrost circuit to an evaporator during a defrost operation to a defrost refrigerant passage provided in each of the heat exchangers. A defrost distributor separate from the vessel, wherein the defrost distributor is provided with the housing of the evaporator. The flow rate of the high-temperature refrigerant flowing in the defrost refrigerant passage of the heat exchanger disposed closer to the housing opening is greater than the flow of the high-temperature refrigerant flowing in the defrost refrigerant passage of the heat exchanger disposed far from the housing opening. Set as
Refrigeration equipment. 2. A drain pan disposed below the evaporator in the housing and receiving ice falling from the evaporator during the defrost operation, and a drain pan heating and melting the ice dropped in the drain pan using a high-temperature refrigerant during the defrost operation. 2. The refrigeration apparatus according to claim 1, further comprising a heater, wherein the drain pan heater is disposed on the defrost circuit upstream of the defrost distributor in the high-temperature refrigerant flow direction. 3. 3. The defrost distributor includes a refrigerant circuit that supplies a part of the high-temperature refrigerant supplied from the defrost circuit to the refrigeration distributor during a defrost operation. A refrigeration apparatus according to claim 1. 4. The refrigerating apparatus according to claim 3, further comprising a check valve in the refrigerant circuit for preventing a flow of the refrigerant from the refrigerating operation distributor to the defrost distributor.