JPS6153630B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention utilizes the in-store air around the case, which has high enthalpy, as a defrosting heat source and sends it to the cooler installed inside the case to remove frost attached to the cooler. This invention relates to the improvement of a flat open case for freezing and refrigeration that uses the so-called air defrosting method.

In place of the well-known heater defrosting method or hot gas defrosting method, the above-mentioned air defrosting method is used to defrost the frost that forms on the surface of the cooler during cold storage operation of the open case. It has attracted attention as a method that promotes energy conservation, and is being adopted in some areas.

When adopting such an air defrosting method, it is particularly desirable to satisfy the following conditions.
In other words, firstly, the basic structure of the open case can be used as is without making any major changes, and the outside air can be efficiently sent to the cooler during defrosting. A type evaporator is used, and during defrosting, not only the inside of the evaporator body but also the U-bend part of the refrigerant coil that protrudes laterally from the end plate of the evaporator and is located outside the cold air ventilation path during cold storage operation. , the expansion valve of the refrigerant circuit attached to the cooler, the distribution unit, etc. can also be defrosted, and in addition, the defrosting air is passed through the case in an open loop, allowing the defrosting air to cool down. The frost exhaust does not immediately flow back into the case, and even during defrosting when the refrigerator is stopped, it suppresses outside air from entering the product display room inside the warehouse to prevent product temperatures from rising as much as possible. requested.

In this regard, the conventional air defrosting method for flat-type show cases is such that outside air is forced into the case from the outside and is allowed to flow only inside the cooler body, just like during cold storage operation. , defrosting air was not forced to flow through the space where the distributor, etc. were located. For this reason
Frost adhering to bends, etc., is more difficult to melt than the inside of the cooler, and often the defrost is not completely defrosted during the specified defrosting time, leaving unmelted frost to form the core. As a result of repeated cold storage operation cycles, the ice gradually grows and turns into large blocks of ice, causing a problem.

This invention was made in consideration of the above points, and its purpose is to defrost the U-bend part of the cooler during defrosting, while satisfying the above conditions and without interfering with the cold storage operation. To provide a flat open case in which air can be actively circulated to perform effective air defrosting.

The present invention will be described in detail below based on illustrated embodiments.

First, the illustrated example shows a so-called double-sided flat open show case, which has a wide depth dimension and has two front and back sides facing the store aisle.
2 is a front panel that covers the front and rear surfaces of the case body, 3 is an inner box that forms a product display room 4, and 5 is a day plate that is located at the center of the refrigerator and protrudes from the bottom of the inner box 3. This is the spray part. In such a case, there is an inner box 3 inside the case body 1.
A cold air circulation duct 6 is partitioned between the outer periphery of the case body 1 and the outer box of the case body 1, and there is a finned coil type cooler 7, which is the evaporator of the refrigerator, and an internal fan on the upstream side thereof. 8 is installed. Note that the internal fan 8 is installed in a wind barrel 9 that constitutes a fan plenum. The cold air circulation ducts 6 are opened at the front and rear upper edges of the case body 1 facing each other, and are used as an air curtain outlet 10 and an air curtain outlet 11. Further, a central air outlet duct 12 is formed which branches from the outlet side of the cooler 7 and communicates with the central display section 5, and at the top of the central display section 5 there is a central air outlet duct 12 extending toward the air curtain air outlet 11. 13 is open. Up to this point is the basic structure of the show case.
With this configuration, if the cooler 7 and the refrigerator fan 8 are operated during cold storage operation, the duct 6
Air circulates through the cooler 7 as shown by arrow A.
The cold air cooled by heat exchange with the case body 1 is blown out from the air curtain outlet 10 and the central outlet 13 toward the air curtain outlet 11, thereby forming an air curtain A' at the upper opening of the case body 1. This prevents outside air from entering the refrigerator,
The products arranged in the product display room 4 are kept cold. Note that by blowing out a portion of the cold air from the central display section 5, it is possible to prevent the temperature inside the refrigerator from increasing in the area near the air curtain inlet 11, and to equalize the cold storage temperature throughout the interior of the refrigerator.

In addition to the above basic structure, the present invention is configured as follows in order to perform air defrosting. First, in the space between the outer box of the case body 1 and the front panel 2, an outside air introduction duct 14 is provided over the entire width of the case. The duct 14 has a lower end that is opened toward the outside of the case body as an outside air intake port 15, and an upper end that serves as an outside air outlet 16 that passes over the upper edge of the outer box of the case body 1 and blows in the air curtain. The mouth 11 is opened inward. Furthermore, a plurality of outside air introduction fans 17, 17' are installed in the suction port of the duct 14 in parallel in the width direction of the case.By operating the fans 17, 17' during defrosting, the outside air suction port 15 The outside air sucked in through the outside air outlet 16
Air is forced into the air curtain inlet 11 from the air curtain. Furthermore, as clearly shown in FIGS. 2 and 3, the U-bend portion 71 of the refrigerant coil protruding laterally from the main body of the cooler 7, and the expansion valve 18 of the refrigerant circuit attached to the cooler 7, A branch ventilation duct 20 for defrosting air, which is partitioned from the cold air circulation duct 6, is formed at the side end portion of the case body surrounding the distributor 19. This duct 20 is surrounded by the illustrated duct walls 21 and 22 and the side plate 23 of the case, and its inlet is directly connected to the outlet 16 of the outside air introduction duct 14 mentioned above.
The outlet on the downstream side is opened toward the cold air circulation duct 6 on the outlet side of the cooler 7. Furthermore, a partition wall 24 extending from the outside air intake port 15 to the discharge port 16 along the duct is provided in the outside air introduction duct 14 in series with the entrance of the branch ventilation duct 20, so that the outside air introduction duct 14 is left and right when viewed from the front. One fan 17' of the plurality of outside air introducing fans is used exclusively for the branch ventilation duct.

Next, the defrosting operation with the above configuration will be described.
When switching from the aforementioned cold preservation operation to defrosting, the cooler 7 stops operating, and the refrigerator fan 8 continues to operate.
Furthermore, outside air introduction fans 17, 17' are added to the new operation. Therefore, the outside air with high enthalpy around the case is sucked into the fans 17, 17' and sent into the case through the outside air introduction duct 14.
In this case, on the one hand, the outside air sucked in through the fan 17 flows through the cold air circulation duct 6 as shown by arrow B in FIGS. 1 and 3 and reaches the internal fan 8.
Defrosting heat is applied from here through the inside of the main body of the cooler 7 by an internal fan 8. On the other hand, the outside air sucked in through the outside air introduction fan 17' immediately enters the branch ventilation duct 20 from the outlet 16 of the outside air introduction duct 14, as shown by arrow C in FIGS. After washing the parts of the refrigerant circuit including the bend part 71, the expansion valve 18, and the distributor 19 and the piping around them and applying defrosting heat to them, the cool air exits from the outlet of the duct 20 and flows into the cold circulation duct 6. It merges with the defrosting air flow of arrow B flowing through the air. This defrosting exhaust gas is blown by a fan to reach the air curtain outlet 10 and the central outlet 13, and is blown out from there to the upper opening of the case body 1 to form an air curtain B' by the defrosting exhaust gas. Moreover, in this case, the air curtain inlet 11
Since the air curtain B' is maintained at a positive pressure by the discharge wind pressure of the outside air introduction fan 17, the air curtain B' is not sucked into the air curtain inlet 11 and collected as in the case of cold storage operation, but continues to push the upper edge of the case body. It will climb over and be dissipated around the case. In other words, the defrosting air flows through the case in an open-loop manner, and the defrosting exhaust forms air curtain B' to effectively suppress outside air from entering the product display room during the defrosting period. It is possible to minimize the rise in product temperature. Moreover, when defrosting,
Not only the main body of the cooler 7, but also the U-bend part 71, etc.
Air defrost can be effectively performed by forcibly sending defrosting air to areas where frost is likely to remain. In addition, since the branch ventilation duct 20 for defrosting air is separated from the cold air circulation duct 6, there is no fear of any obstruction to the circulation of cold air during cold storage operation.

As described above, the present invention provides a branch ventilation duct for defrosting air that surrounds the U-bend portion of the cooler and is separated from the cold air circulation duct, and makes the inlet of the branch ventilation duct face the outside air introduction fan. In this way, during defrosting, outside air with high enthalpy is forced into the cold air circulation duct and the branch ventilation duct. Therefore, it is possible to provide an excellent energy-saving flat open show case that fully satisfies the above conditions and can perform effective air defrosting.

[Brief explanation of the drawing]

1 to 3 show the configuration of an embodiment of the present invention, and FIGS. 1 and 2 are longitudinal cross-sections of the center and end portions of the case along arrows - and - in FIG. 3, respectively. The side view and FIG. 3 are cross-sectional plan views of the main parts. 1...Case body, 3...Inner box, 4...Product display room, 6...Cold air circulation duct, 7...Cooler, 7
1... U-bend part of the cooler, 8... Internal fan,
10...Air curtain outlet, 11...Air curtain outlet, 14...Outside air introduction duct, 17,1
7'... Outside air introduction fan, 18... Expansion valve, 19
... Distributor, 20 ... Defrost air branch ventilation duct, A ... Cold air flow, B, C ... Defrost air flow, A' ... Cold air curtain, B' ... Defrost exhaust air curtain.

Claims (1)

[Claims] 1 In a flat case with an open top, the air curtain outlet and inlet are opened on the front and rear sides of the case body to form a cold air circulation duct between the outer box and the inner box of the case body, and to A finned coil type cooler and an internal fan are installed inside the circulation duct, and a cold air curtain is blown out from the top opening of the case body during cold storage operation. an outside air introduction duct that opens outward and has an outside air outlet at the other end facing the air curtain suction port, an outside air introduction fan that sends outside air to the outside air introduction duct, and a U-bend portion of the cooler. , is equipped with a defrosting air branch ventilation duct that surrounds the expansion valve, distributor, etc. of the refrigeration circuit, and is partitioned into the cold air circulation duct with its inlet facing the outside air intake fan, allowing outside air to be introduced during defrosting. The outside air sucked in by the operation of the outside air intake fan through the duct is divided into the inside of the cooler and the U-bend section to provide defrosting heat to each section, and the defrosting exhaust is blown out from the air curtain outlet to open the top surface of the case body. A flat open case characterized by forming an air curtain in the upper part.