JP2005351591A - Cooling storage shed - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling storage shed for effectively avoiding the extension of a defrosting time with frost formed on an outlet pipe of an expansion valve. <P>SOLUTION: In the cooling storage shed, refrigerant depressurized by an expansion valve 26 flows into an evaporator 16 for evaporation, and cold air heat-exchanged with the evaporator 16 is circulated into a storage chamber 9 via a duct 8 with a blower 7. The supply of the refrigerant to the evaporator 16 is stopped and the blower 7 is operated when defrosting the evaporator 16. Air discharged from the blower 7 hits the outlet pipe 41 of the expansion valve 26. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cooling storage such as a low-temperature showcase or a refrigerator.

  Conventionally, for example, in a low-temperature showcase installed in a convenience store or a supermarket, a storage room for displaying products is formed in a heat insulating wall, and a duct is formed outside thereof, and an evaporator (cooler) and a blower are provided in the duct. The cool air exchanged with the evaporator is circulated into the storage chamber by a blower (see, for example, Patent Document 1).

At this time, the refrigerant is evaporated by flowing the refrigerant decompressed by the expansion valve of the refrigerant circuit, but frosting grows in the evaporator due to such cooling operation. The supply of the refrigerant was stopped, and only the blower was operated to blow air to the evaporator, so that frost formation on the evaporator was melted and removed.
JP-A-9-269179

  Here, the defrosting of the evaporator may be terminated depending on the time, or may be terminated when the evaporator has risen to a predetermined temperature. Frost has accumulated and will eventually cause frost blockage.

  On the other hand, the place where the temperature becomes lowest in the refrigerant circuit is the outlet pipe of the expansion valve where the evaporation of the refrigerant is started. Therefore, although frost formation is most likely to grow in the outlet pipe of the expansion valve, conventionally no consideration has been given to frost formation in the outlet pipe of the expansion valve, and frost residue is left in the outlet pipe during defrosting. As a result, the time required for defrosting is remarkably increased, resulting in a problem that the cooling capacity of the storage room is adversely affected.

  The present invention was made to solve the conventional technical problem, and provides a cooling storage that can effectively avoid the extension of the defrosting time due to frost formation on the outlet pipe of the expansion valve. Objective.

  According to the first aspect of the present invention, there is provided a cooling storage device in which a refrigerant decompressed by an expansion valve is caused to flow through an evaporator to evaporate, and cool air exchanged with the evaporator is circulated into a storage chamber through a duct by an air blower. The refrigerant supply is stopped, the blower is operated to defrost the evaporator, and the air discharged from the blower is applied to the outlet piping of the expansion valve.

  The cooling storage of the invention of claim 2 is characterized in that a through hole is formed in the wall constituting the duct from the discharge side of the blower to the evaporator in the above, and this through hole is made to correspond to the outlet pipe of the expansion valve. To do.

  The cooling storage of the invention of claim 3 is characterized in that, in claim 1, the outlet pipe of the expansion valve is arranged in the duct from the discharge side of the blower to the evaporator.

  The cooling storage of the invention of claim 4 is characterized in that the outlet pipe of the expansion valve is arranged on the air outflow side of the evaporator in claim 1.

  In the cooling storage of the invention of claim 5, the refrigerant depressurized by the expansion valve is caused to flow through the evaporator to evaporate, and the cool air exchanged with the evaporator is circulated into the storage chamber through the duct by the blower. This is characterized in that the outlet pipe of the expansion valve is disposed at a location where the defrost water from the evaporator flows down.

  The cooling storage of the invention of claim 6 comprises a drain port for discharging the defrost water from the evaporator and an opening / closing means for opening and closing the drain port, and the opening / closing means during the defrosting of the evaporator. It is characterized by closing the drain port.

  According to a seventh aspect of the present invention, there is provided a cooling storage for defrosting the evaporator by flowing the refrigerant decompressed by the expansion valve to the evaporator and evaporating it, and stopping the supply of the refrigerant to the evaporator. A plurality of expansion valves are provided, and after the defrosting of the evaporator, the refrigerant is switched to flow through one of the expansion valves.

  According to the first aspect of the present invention, the refrigerant decompressed by the expansion valve is caused to flow through the evaporator to evaporate, and the cool air exchanged with the evaporator is circulated into the storage chamber through the duct by the blower, and the refrigerant to the evaporator In the cooling storage where the supply is stopped and the blower is operated to defrost the evaporator, the air discharged from the blower is applied to the outlet piping of the expansion valve. It is possible to quickly remove frost on the outlet pipe by applying wind from the blower. This makes it possible to quickly defrost the outlet piping of the expansion valve, which is likely to form frost, significantly shorten the time required for defrosting the evaporator, and minimize deterioration of the cooling capacity in the storage chamber due to defrosting. become able to.

  In this case, if a through hole is formed in the wall constituting the duct extending from the discharge side of the blower to the evaporator as in the invention of the second aspect and this through hole is made to correspond to the outlet pipe of the expansion valve, it is simple. With the configuration, the wind from the blower can be effectively applied to the outlet piping of the expansion valve to promote melting of frost formation at the time of defrosting.

  Further, if the outlet pipe of the expansion valve is arranged in the duct extending from the discharge side of the blower to the evaporator as in the invention of claim 3, the outlet pipe of the expansion valve is exposed to the wind from the blower and the defrosting is performed. Frost can be melted effectively.

  Further, if the outlet pipe of the expansion valve is arranged on the air outflow side of the evaporator as in the invention of claim 4, during the cooling operation, the cool air dried through the evaporator hits the outlet pipe of the expansion valve, and goes to the outlet pipe. It becomes possible to suppress frost formation. And since the exit piping of an expansion valve is exposed to the wind from an air blower during defrosting, defrosting comes to be performed effectively.

  In the invention of claim 5, the refrigerant depressurized by the expansion valve is caused to flow through the evaporator to evaporate, and the cool air exchanged with the evaporator is circulated into the storage chamber through the duct by the blower, and the defrosting of the evaporator is performed. Because the outlet piping of the expansion valve is arranged at the location where the defrosted water from the evaporator flows down in the cooling storage that performs the operation, the defrosted water from the evaporator is brought into contact with the outlet piping of the expansion valve during the defrosting. Will be able to. This quickly melts the frost on the outlet piping of the expansion valve, where frost formation is likely to occur, significantly shortening the time required for defrosting the evaporator and minimizing the deterioration of the cooling capacity in the storage chamber due to the defrosting Will be able to.

  In this case, if an opening / closing means for opening / closing the drain port for discharging defrost water from the evaporator as in claim 6 is provided and the drain port is closed by the opening / closing means during the defrosting of the evaporator, During the defrosting, defrosted water is accumulated and the outlet piping of the expansion valve is immersed, so that frost melting can be further promoted.

  In the invention of claim 7, the refrigerant decompressed by the expansion valve is caused to flow through the evaporator to evaporate, and the expansion valve is installed in a cooling storage for defrosting the evaporator by stopping supply of the refrigerant to the evaporator. Since a plurality of installed and switched after defrosting of the evaporator to flow the refrigerant through one of the expansion valves, the frost is distributed to the outlet piping of the plurality of expansion valves, and the frost is not flowing through the refrigerant It can be melted in. This effectively removes frost on the outlet pipe of the expansion valve, which is likely to form frost, significantly shortens the time required for defrosting the evaporator, and minimizes deterioration of the cooling capacity in the storage chamber due to defrost. Can be suppressed.

  Next, an embodiment of the present invention will be described in detail with reference to the drawings.

  1 is a longitudinal side view of a low temperature showcase 1 as an embodiment of a cooling storage to which the present invention is applied, FIG. 2 is a transparent rear view of the low temperature showcase 1, and FIG. A plan view is shown. The low-temperature showcase 1 according to the embodiment is a vertical open showcase installed in a store such as a convenience store or a supermarket. The insulation wall 2 has a substantially U-shaped cross section, and is installed on both sides of the insulation wall 2 at the installation site. It is comprised from the side plate 3 attached. A partition plate 4 is attached to the inside of the heat insulating wall 2 with a space therebetween, and a duct 8 is provided between the heat insulating wall 2 and the partition plate 4, and a storage chamber 9 serving as a space to be cooled is inside the partition plate 4. It is said that.

  A plurality of shelves 11 are built in the storage chamber 9, and a deck pan 12 is attached to the bottom of the storage chamber 9. A fan case 14 incorporating a blower 7 is installed below the deck pan 12. In addition, an evaporator 16 that constitutes a refrigerant circuit of the cooling device is vertically provided in the duct 8 at the rear thereof. An evaporator lower cover 13 comprising an upper wall and left and right walls is installed between the fan case 14 and the duct 8, and the fan case 14 on the discharge side of the blower 7 communicates with the lower end of the duct 8 (the air inflow side of the evaporator 16). doing.

  A discharge port 23 is provided at the upper edge of the front opening 21 of the storage chamber 9, and the discharge port 23 communicates with the upper front end of the duct 8. A suction port 24 is formed at the lower edge of the opening 21 and communicates with the suction side of the blower 7 provided in the fan case 14 below the deck pan 12. Thereby, a series of ducts for circulating cold air from the lower side of the storage chamber 9 to the rear side and the upper side are configured.

  When the blower 7 in the fan case 14 is operated, air is sucked in from the blower 7 suction side below the deck pan 12 and blown out toward the rear duct 8 through the evaporator lower cover 13. Then, it passes through the evaporator 16 and is blown up while exchanging heat, flows out from the air outflow side (upper end) of the evaporator 16, rises, and from the discharge port 23 on the upper edge of the opening 21 to the lower suction port 24. It will be blown out towards.

  As a result, a cold air curtain is formed in the opening 21 of the storage chamber 9, and intrusion of outside air from the opening 21 is prevented or suppressed, and a part of the cold air curtain is circulated in the storage chamber 9. The inside of the storage chamber 9 is cooled. Then, the cold air flows from the suction port 24 to the lower side of the deck pan 12 and is sucked into the blower 7 again.

  Here, the evaporator 16 is a so-called plate fin type evaporator, and is configured by attaching a plurality of fins 34 to a refrigerant pipe 32 bent in a meandering manner. Reference numeral 33 denotes a tube plate that holds the refrigerant pipe 32 on both sides of the fins 34, and the refrigerant pipe 32 is bent in a U shape outside the tube plate 33.

  Reference numeral 32 </ b> A denotes a refrigerant inlet pipe, which is drawn out from the upper part of the tube sheet 33. Furthermore, 32B is a refrigerant | coolant exit piping, and is withdraw | derived from the lower part of the evaporator 16 to the tube-sheet 33 outer side. Reference numeral 26 denotes an expansion valve (an electric expansion valve is used in this embodiment), and its outlet pipe 41 is connected to the refrigerant inlet pipe 32A of the evaporator 16. In this case, the outlet pipe 41 of the expansion valve 26 is provided along the outside of the right side wall 13A of the evaporator lower cover 13, and the through hole 20 corresponding to the outlet pipe 41 is formed in the right side wall 13A. A plurality (two in the embodiment) are formed along the direction.

  The inlet of the expansion valve 26 is connected to a high-pressure pipe of a condensing unit (not shown) (installed in a machine room of a store and the evaporators 16 of the plurality of low-temperature showcases 1 receive refrigerant supply). The refrigerant outlet pipe 32B is connected to the low pressure pipe of the condensing unit.

  With the above configuration, when a compressor (not shown) of the condensing unit is operated by a control device (not shown), the high-temperature gas refrigerant discharged from the compressor is also condensed by a condenser (not shown). After reaching the expansion valve 26 and being decompressed here, the refrigerant enters the evaporator 16 through the outlet pipe 41 and the refrigerant inlet pipe 32A. Since the refrigerant begins to evaporate after leaving the expansion valve 26, the refrigerant circuit from the outlet pipe 41 to the evaporator 16 has a low temperature. Then, the refrigerant is gasified and is repeatedly circulated through the refrigerant outlet pipe 32B of the evaporator 16 and sucked into the compressor of the condensing unit.

  When the blower 7 is operated, as described above, air is sucked from the blower 7 suction side below the deck pan 12 and blown out toward the rear duct 8 through the evaporator lower cover 13. Then, the cold air cooled by exchanging heat with the evaporator 16 is blown out from the discharge port 23 at the upper edge of the opening 21 toward the suction port 24 at the lower edge, forming a cool air curtain while being in the storage chamber 9. Will be cooled.

  In such a cooling operation, the moisture in the circulating air becomes frost and grows on the evaporator 16 as frost. In particular, since the outlet pipe 41 of the expansion valve 26 has the lowest temperature, frost formation grows most. Therefore, for example, the control device periodically performs a defrosting operation of the evaporator 16. In this defrosting operation, the expansion valve 26 is fully closed (the refrigerant supply to the evaporator 16 is thereby stopped), and the blower 7 is continuously operated. In this way, the temperature of the evaporator 16 gradually increases due to the ventilation with the refrigerant supply stopped, and frost formation is melted.

  In this case, since the through holes 20 and 20 are formed in the right side wall 13A of the evaporator lower cover 13, the air discharged from the blower 7 passes through not only during the cooling operation described above but also during the defrosting operation. It blows out from the holes 20 and 20. Since the blown air is blown against the outlet pipe 41 of the expansion valve 26, the frost that has grown on the outlet pipe 41 is also rapidly melted.

  Here, the control device ends the defrosting operation when the temperature of the evaporator 16 reaches a predetermined defrosting end temperature and restarts the cooling operation. However, the frosting of the outlet pipe 41 of the expansion valve 26 is not performed. If left, the temperature rise of the evaporator 16 is delayed, and the remaining frost grows, and there is a risk that the evaporator 16 will eventually clog the frost.

  However, in the present invention, since the outlet pipe 41 where frost formation is most likely to grow can be quickly defrosted as described above, the time required for the defrosting of the evaporator 16, that is, the time until the defrosting end temperature is reached is also significant. It will be shortened. Thereby, the deterioration of the cooling capacity in the storage chamber 9 due to defrosting can be minimized. Moreover, since frost residue can also be eliminated, frost blockage can be effectively prevented.

  In particular, through holes 20, 20 are formed in the right side wall 13 </ b> A of the evaporator lower cover 13 that forms a duct from the discharge side of the blower 7 to the evaporator 16, and the through holes 20, 20 are connected to the outlet piping 41 of the expansion valve 26. Therefore, it is possible to effectively apply the wind from the blower 7 to the outlet pipe 41 of the expansion valve 26 with a relatively simple configuration to promote melting of frost formation during defrosting.

  Next, FIG. 4 shows another embodiment of the present invention. In this case, the outlet pipe 41 of the expansion valve 26 is drawn into the evaporator lower cover 13 (which constitutes a duct) extending from the discharge side of the blower 7 to the evaporator 16. Thus, by arranging the outlet pipe 41 in the duct from the discharge side of the blower 7 to the evaporator 16, the outlet pipe 41 of the expansion valve 26 is exposed to the wind from the blower 7, and frost formation at the time of defrosting is performed. It becomes possible to melt effectively.

  FIG. 5 shows another embodiment of the present invention. In this case, the outlet pipe 41 of the expansion valve 26 is arranged on the air outflow side above the evaporator 16. If the outlet pipe 41 is arranged on the air outflow side of the evaporator 16 in this way, the cool air dried through the evaporator 16 hits the outlet pipe 41 of the expansion valve 26 during the cooling operation, and frost formation on the outlet pipe 41 is prevented. It will be possible to suppress. Since the outlet pipe 41 of the expansion valve 26 is exposed to the wind from the blower 7 during the defrosting operation, the outlet pipe 41 that is most likely to be frosted is effectively defrosted.

  Next, FIG. 6 shows another cross-sectional view of the lower part of the low-temperature showcase 1 of the present invention. In the heat insulating wall 2 below the deck pan 12, a drain port 36 is formed on the front side of the fan case 14. The bottom surface 2A of the heat insulating wall 2 is inclined downward toward the drain port 36. Further, the drain port 36 is provided with a plug 38 as an opening / closing means that is driven by a solenoid 37 to open and close the drain port 36. ing. In this case, the outlet pipe 41 of the expansion valve 26 is arranged along the bottom surface 2A of the heat insulating wall 2 from the lower side of the evaporator 16 to the drain port 36 (FIG. 6).

  Next, the operation in this case will be described. During the cooling operation, the control device pulls down the plug 38 by the solenoid 37 and closes the drain port 36. When the defrosting operation is started, the defrosting water drops from the evaporator 16 and flows through the bottom surface 2A toward the drain port 36. Therefore, the outlet pipe 41 of the expansion valve 26 flows into the defrosting water flowing down. Will be in contact. Therefore, frost formation on the outlet pipe 41 of the expansion valve 26 where frost formation tends to occur is rapidly melted.

  The control device does not open the drain port 36 even when the defrosting operation is started. Accordingly, defrosted water generated during the defrosting is stored on the bottom surface 2A of the heat insulating wall 2, and the outlet pipe 41 of the expansion valve 26 is immersed in the defrosted water. Thereby, the melting of frost is further promoted, so that the frost on the outlet pipe 41 is quickly melted, the time required for the defrosting of the evaporator 16 is remarkably shortened, and the cooling capacity in the storage chamber 9 by the defrosting is reduced. Deterioration will be minimized. The control device pushes up the plug 38 by the solenoid 37 immediately before finishing the defrosting operation, opens the drain port 36 and discharges the defrosting water.

  Next, FIG. 7 shows a part of another refrigerant circuit of the low-temperature showcase 1 of the present invention. In this case, a plurality (two in the embodiment) of expansion valves 26A and 26B are provided, and these are connected in parallel to each other in the refrigerant circuit. The outlet pipes 41A and 41B of the expansion valves 26A and 26B are joined together and connected to the refrigerant inlet pipe 32A of the evaporator 16.

  Next, the operation in this case will be described. The control device uses one of the expansion valves 26A or 26B during the cooling operation. For example, in the current cooling operation, if the expansion valve 26B is fully closed and the opening degree of the expansion valve 26A is adjusted to supply the refrigerant to the evaporator 16, the expansion valve 26A is also fully closed from the start of the defrosting operation. And When the cooling operation is resumed after the defrosting operation is completed, the expansion valve 26B is now opened, and the refrigerant is supplied to the evaporator 16 while adjusting the valve opening degree. At this time, the expansion valve 26A is fully closed. Thereafter, this is repeated and the expansion valves 26A and 26B are switched and used each time defrosting is performed.

  As described above, if a plurality of expansion valves 26A and 26B are provided and switched after defrosting of the evaporator 16 and the refrigerant is allowed to flow to any one of the expansion valves 26A or 26B, the frosting of the plurality of expansion valves 26A and 26B occurs. The outlet pipes 41A and 41B can be dispersed. Further, frost adhering to the outlet pipe (41A in the above case) of the expansion valve (26A in the above case) used last time causes the refrigerant to flow into the expansion valve 26B during a period when the refrigerant is not flowing next time. Melts during the period. This effectively removes frost on the outlet pipe of the expansion valve, which is likely to be frosted, significantly shortens the time required for defrosting the evaporator 16, and deteriorates the cooling capacity in the storage chamber 9 due to defrosting. Can be minimized.

  In each of the above embodiments, the electric expansion valve is used as the expansion valve. However, the present invention may be applied by using a temperature type expansion valve and controlling whether or not the refrigerant is supplied to the evaporator with a liquid electromagnetic valve. It is valid. In the embodiments, the present invention is applied to an open showcase. However, the present invention is not limited to this, and is effective for home / business refrigerators, closed type showcases, and the like. Furthermore, in the defrosting operation of the embodiment, the evaporator was defrosted by blowing air from a blower, but in addition, the evaporator may be heated by an electric heater or the like.

It is a vertical side view of the low-temperature showcase as one Example of the cooling storehouse to which this invention is applied. It is a see-through | perspective back view of the low-temperature showcase of FIG. (Example 1) which is a top view of the evaporator part of the low-temperature showcase of FIG. It is a top view of the evaporator part of the low-temperature showcase of Example 2 of this invention. It is a front view of the evaporator part of the low-temperature showcase of Example 3 of this invention. It is a vertical side view of the low-temperature showcase lower part of Example 4 of this invention. It is a refrigerant circuit figure of the expansion valve part of the low-temperature showcase of Example 5 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Low-temperature showcase 2 Heat insulation wall 2A Bottom face 4 Partition plate 7 Blower 8 Duct 9 Storage room 13 Evaporator lower cover 14 Fan case 16 Evaporator 20 Through-hole 26, 26A, 26B Expansion valve 36 Drain port 37 Solenoid 38 Plug 41, 41A , 41B Outlet piping

Claims (7)

The refrigerant decompressed by the expansion valve is caused to flow through the evaporator to evaporate, and the cool air exchanged with the evaporator is circulated into the storage chamber through the duct by the blower, and the supply of the refrigerant to the evaporator is stopped, In the cooling storage that operates the blower to defrost the evaporator,
A cooling storage, wherein the air discharged from the blower is applied to an outlet pipe of the expansion valve.   The cooling storage according to claim 1, wherein a through hole is formed in a wall constituting a duct extending from the discharge side of the blower to the evaporator, and the through hole is made to correspond to an outlet pipe of the expansion valve.   The cooling storage according to claim 1, wherein an outlet pipe of the expansion valve is disposed in a duct extending from a discharge side of the blower to the evaporator.   The cooling storage according to claim 1, wherein an outlet pipe of the expansion valve is arranged on the air outflow side of the evaporator. In the cooling storage for defrosting the evaporator while circulating the refrigerant depressurized by the expansion valve through the evaporator to evaporate, circulating the cool air exchanged with the evaporator through the duct through the duct,
A cooling storage, wherein an outlet pipe of the expansion valve is arranged at a location where the defrost water from the evaporator flows down.   A drain port for discharging defrost water from the evaporator and an opening / closing means for opening / closing the drain port, wherein the drain port is closed by the opening / closing means during defrosting of the evaporator, The cooling storage box according to claim 5. In the cooling storage that performs the defrosting of the evaporator by stopping the refrigerant supply to the evaporator by flowing the refrigerant decompressed by the expansion valve to the evaporator and evaporating it,
A cooling storage, wherein a plurality of the expansion valves are provided, and are switched after defrosting of the evaporator to flow a refrigerant through any of the expansion valves.

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