JPH065586Y2 - Freezer / Refrigerator Open Showcase - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a freezer-refrigerating open showcase, and more particularly to control of hot gas when hot gas is used for defrosting.

<Prior Art> FIGS. 2 to 5 are views showing an example of a conventional art.
The figure is a cross-sectional view of a freezer-refrigerating open showcase disclosed in Japanese Utility Model Publication No. 61-114286, where 1 is a case body and 2 is a case body.
Is an opening portion, 3 is a duct plate that divides the inside of the case body 1 into a product storage portion 4 and a cold air circulation duct 6, and 5 is a protective duct 7 formed between the outside of the cold air circulation duct 6 and the case body 1. It is a duct board.

A part of the cold air circulation duct 6 is divided into two passages 8 and 9 by a division plate 10, and blowers 11a and 11b for circulating air and a cooler 12 for cooling the air are provided in the passages 8 and 9, respectively.
The a and 12b are arranged so that the air sucked from the suction port 14 of the cold air circulation duct 6 is cooled and blown out from the blowout port 13.

In addition, the blower 15 is also installed in the protective duct 7,
The air sucked from the suction port 17 is blown out from the blowout port 16.

As shown in FIG. 3, the refrigerant circuit of the coolers 12a and 12b has a liquid refrigerant solenoid valve 18, branch inlet pipes 27 and 28 for a liquid refrigerant inlet pipe 26 from a condensing unit (not shown).
It is connected via the expansion valves 19 and 20, and is also connected to the refrigerant return pipe 33 to the condensing unit via the outlet pipes 31 and 32, the four-way valves 21 and 22, and the collecting pipe 46, and from the condensing unit. The hot gas pipe 34 is a solenoid valve for opening and closing the pipeline 2
3, hot gas branch pipes 47, 35, and the four-way valves 21, 22 are connected to the outlet pipes 31, 32. A capillary tube 24 is connected between the inlet tubes 29, 30 of the coolers 12a, 12b.

FIG. 4 shows the refrigerant circuit of the showcase and the condensing unit. That is, the refrigerant compressed by the compressor 36 is condensed by the condenser 37, passes through the liquid reservoir 38, enters the coolers 12a and 12b of the showcase by the liquid refrigerant inlet pipe 26, passes through the refrigerant return pipe 33, and the accumulator. Return from 39 to compressor 36.

The hot gas pipe 34 is branched from a discharge pipe 40 that connects the compressor 36 and the condenser 37 to each other.

In the above configuration, the suction port 14 is blown by the blowers 11a and 11b.
The air sucked in from the coolers 12a and 12b is cooled by exchanging heat with the refrigerant flowing in the cooling pipes of the coolers 12a and 12b, and then rectified and blown out from the blowout port 13 to form an air curtain by the cool air to form the product storage unit 4 Keep the products stored inside cool. In order to improve the cold insulation performance, the air blown from the suction port 17 by the blower 15 is blown out from the blowout port 16 using the protective duct 7 to form a protective air curtain on the outside of the cool air curtain.

If such a cool operation is continued for a long time, the coolers 12a, 12a
Moisture in the air condenses on b to form frost, which lowers the cooling capacity and also reduces the flow rate of the cool air blown out from the air outlet 13 to make it impossible to form the cool air curtain. It is necessary to remove the frost adhering to the pool coolers 12a, 12b, but a plurality of coolers are provided as described above in order to maintain the cold insulation performance during defrosting, while the other is defrosting one cooler. The defroster is designed to be able to continue cooling and to defrost alternately.

FIG. 5 is an operation control chart when defrosting the cooler is performed at regular intervals. At time T ₁ , the coolers 12a, 12
Both b are in the cooling operation, and the blowers 11a and 11b are both in operation, and the liquid refrigerant solenoid valve 18 is energized and opened. Therefore, the liquid refrigerant from the condensing unit is the third
From the liquid refrigerant inlet pipe 26 to the solenoid valve 1
8, through the branch inlet pipes 27, 28 to the expansion valves 19, 20 where they are decompressed and enter the coolers 12a, 12b to cool the air to become gas refrigerant, the outlet pipes 31, 32, the four-way valves 21, 22 , And returns to the condensing unit via the collecting pipe 46 and the refrigerant return pipe 33.

Predetermined time has elapsed, at time T _2, the cooling device 12a becomes the defrosting operation, also stops the blower 11a. Then, the liquid refrigerant solenoid valve 18 is closed, the four-way valve 21 is energized to switch as shown by the broken line, and the conduit opening / closing solenoid valve 23 of the hot gas pipe 34 is opened. Then, the hot gas from the condensing unit flows from the hot gas pipe 34 to the pipe opening / closing solenoid valve 23, the hot gas branch pipe 47, the four-way valve 21, as shown by the broken line arrow in FIG.
It enters the cooler 12a through the outlet pipe 31, where the heat radiation is defrosted and liquefied by this, and then it is decompressed through the capillary 24 and enters the cooler 12b. Then, the air is cooled here to become a gas refrigerant, and returns to the condensing unit through the outlet pipe 32, the four-way valve 22, the collecting pipe 46, and the refrigerant return pipe 33, and the defrosting is performed in this manner. Defrosting of the cooler 12b is performed in the same manner.

(Problems to be solved by the invention) In the open showcase, the hot gas pipe 34 connected to the coolers 12a and 12b extends relatively long. Therefore,
From the branch point 48 between the compressor 36 and the condenser 37 to the conduit opening / closing solenoid valve 23 near the cooler, the air is cooled by the ambient air. Then, the gas refrigerant flowing into the hot gas pipe 34 condenses into a liquid refrigerant, and stays in the hot gas pipe 34 in a liquid state.

During non-defrosting, the hot gas branch pipes 47, 35 between the pipe opening / closing solenoid valve 23 and the four-way valves 21, 22 are at low pressure. Therefore, when a pipe-off solenoid valve 23 in order to start defrosting at time T ₃ to open, the refrigerant that is a high pressure by the liquid state flows into the four-way valve for example 21 momentarily defrosting side. The flow of this liquid refrigerant is
The four-way valve 21 exhibited a so-called water hammer action (liquid hammer action), and in some cases, the four-way valve 21 was damaged.

The present invention solves the above problems. An object of the present invention is to obtain a freezer-refrigerating open showcase in which the fear of breakage of the four-way valve is eliminated by devising the control means during defrosting.

<Means for Solving the Problems> In order to achieve the above object, the present invention divides a part of the cool air circulation duct formed in the case body into a plurality of passages, and installs a blower and a cooler in each passage. In a freezer-refrigerating open showcase in which at least one of the coolers is defrosted by hot gas and the cooling operation is performed by the other cooler at regular intervals, a branch is formed from the discharge pipe of the compressor. The opening operation for defrosting the pipe opening / closing solenoid valve provided in the hot gas pipe is controlled to the open position after repeating intermittent opening / closing a plurality of times at the beginning of the operation.

<Operation> When switching to the defrosting operation after the lapse of the required time during the cooling operation,
The four-way valve on the defrosting side is switched and the pipe opening / closing solenoid valve is opened. In this opening operation, when the defrosting operation is started, it is not fully opened at once, and intermittent opening and closing is repeated a plurality of times at the beginning of the operation. By the plural opening / closing operations, the high-pressure liquid refrigerant accumulated in the hot gas pipe gradually flows out from the pipe opening / closing solenoid valve to the low-pressure hot gas branch pipe, and further reaches the four-way valve in the opening operation.

The four-way valve is fully opened while the pipeline opening / closing valve is repeatedly opened and closed multiple times. Therefore, the liquid refrigerant does not suddenly flow into the four-way valve at the same time as the defrosting starts to cause the liquid hammer action, that is, the damage of the four-way valve can be prevented.

<Embodiment> An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows an operation control chart when defrosting the coolers 12a and 12b (see FIG. 2 and subsequent figures) at regular time intervals, except for the control of the pipe opening / closing solenoid valve 23. This is similar to the conventional control pattern of FIG.

The feature of this embodiment, when at time T _2, mode changes in the defrosting operation operation, the opening operation of the conduit-opening-and-closing solenoid valve 23 of the hot gas tube 34, initially was controlled opening and closing operations of a plurality of times over several seconds Where it is.

In FIG. 1, at the defrosting start time T ₂ , one defrosting side four-way valve, in this case, the four-way valve 21 is switched to connect the hot gas branch pipe 47 and the outlet pipe 31 from the cooler 12a. . In this case, the four-way valve 21 does not switch instantaneously, but completes switching in the required time, that is, fully opens. The pipe opening / closing solenoid valve 23 enters the opening operation of the hot gas pipe 34 at time T ₂ , but at the beginning of this opening, it opens for example within 5 seconds and then immediately switches to the closed position for a plurality of intermittent opening / closing operations. It is repeated (twice in the figure), and then controlled to maintain the open position.

By such control means, the liquefied refrigerant in the hot gas pipe 34 will flow little by little. Therefore, it is possible to suppress the problem that the four-way valve 21 suddenly flows into the four-way valve 21 during the opening operation, that is, it is possible to prevent the liquid hammer action on the four-way valve 21.

The above-described operation control of the pipeline opening / closing solenoid valve 23 can be performed by means such as a member such as a relay, a timer, a counter, etc. and a circuit configuration known. Incidentally, the intermittent opening / closing of the pipe opening / closing solenoid valve 23 during the defrosting operation is started by the defrosting operation, that is, the four-way valve.
It may be performed at the same time as the start of the switching operation of 21, or immediately before or immediately after.

<Effect of the Invention> As described above, according to the present invention, the operation of the solenoid valve for opening and closing the hot gas pipe during defrosting is initially controlled to the open position after repeating intermittent opening and closing a plurality of times. Since this is done, the liquid refrigerant in the hot gas pipe can be made to flow little by little beforehand. As a result, it is possible to prevent the liquid refrigerant from causing a liquid hammer action on the four-way valve that is switched during defrosting. That is, it is possible to prevent the four-way valve from being damaged by the liquid hammer action and to obtain a freezer-refrigerating open showcase excellent in safety and durability.

[Brief description of drawings]

FIG. 1 is a defrosting operation control chart of a freezing / refrigerating open showcase according to an embodiment of the present invention, FIG. 2 is a sectional view of a conventional freezing / refrigerating open showcase, and FIG. 3 is a conventional freezing / refrigerating storage. Fig. 4 is a piping configuration diagram of the open showcase, Fig. 4 is a refrigerant circuit configuration diagram of the conventional freezing-refrigerating open showcase, and Fig. 5 is a defrosting operation control chart of the conventional freezing-refrigerating open showcase. In the figure, 1 is a case body, 2 is an opening, 6 is a cold air circulation duct, 11a and 11b are blowers, 12a and 12b are coolers, 23 is a line opening / closing solenoid valve, 34 is a hot gas pipe, and 36 is a compression. Machine, 37 is a condenser, and 40 is a discharge pipe.

Claims (1)

[Scope of utility model registration request] 1. A part of a cold air circulation duct formed in a case body is divided into a plurality of passages, and a blower and a cooler are arranged in each passage, and at least one of the coolers is hot at regular intervals. In a freezer-refrigerator open showcase in which the cooling operation is performed by another cooler while defrosting with gas, when defrosting the pipe opening / closing solenoid valve provided in the hot gas pipe branched from the discharge pipe of the compressor A freezing / refrigerating open showcase characterized by opening and closing the opening operation after repeating intermittent opening and closing a plurality of times at the beginning of the operation.