JPS60196583A - Method of controlling operation of refrigerating open showcase - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field to which the Invention Pertains] The present invention relates to an operation control method for a refrigerated/refrigerated open showcase that forms an air curtain of cold air in an opening formed on the front surface of the case.

[Prior art and its problems]

Some refrigerator/freezer open showcases are equipped with two coolers in the duct to prevent the cooling capacity from decreasing, and the coolers are operated alternately for cooling and defrosting.
First, the overall structure and conventional operation control method of such a frozen/refrigerated open showcase will be explained, thereby clarifying the purpose of the present invention.

As shown in Figure 1, the frozen/refrigerated open showcase is
A product storage compartment (4) and a cold air circulation duct (6) are constructed using a duct plate (3) inside the main body (1) which has an opening (2) for entering and exiting products.
In addition, the duct plate (5) divides the cold air circulation duct (6) and the protective air circulation duct (7), and a part of the cold air circulation duct (6) is further divided into a passage (16) by the partition plate (16). 17
a) A cooler (18a) is installed in the passage (17a), a cooler (18b) is installed in the passage (17b), and a cold air circulation duct (6) and a protective air circulation duct are installed. The upper and lower ends of (7) are connected to the cold air outlet (8
), protective air outlet (9) and suction port (10) (11)
and the inlet (10) of the cold air circulation duct (6).
) side is equipped with a blower (12), and a protective air circulation duct (7
) is provided with a blower (13) on the outlet (9) side.

As shown in FIG. 2, these two coolers (18a) (1-8b) each have a
An expansion valve (20a) is installed in the refrigerant liquid pipe (1, 9a) (19b) of
(20b) are arranged, each expansion valve (20a) (20b
) on the upstream side of each solenoid valve (21a”: (2l b
) is inserted to form a refrigerant circuit, and this refrigerant circuit is connected to the condensing unit 7) (22). In the figure, (23) is a timer control device that controls opening and closing of the electromagnetic valves ('21a) and (21'b).

In such a freezer/refrigeration open showcase, the inside of the refrigerator is cooled by forming an air curtain of cold air and protective air blown out from the cold air outlet (8) and the protective air outlet (9). This cold air and protective air are connected to the opening (2).
While preventing indoor air from entering the room, the cold air intake port (10)
, is sucked into the protective air suction port (11). The air sucked in by the blower (12) from the cold air suction port (10) is brought to a predetermined temperature by one of the two coolers (18a) (18b) in the cooling operation (for example, 18a). The cooled air is cooled down to a temperature of 100.degree. C. and sent to the cold air outlet (8) again. At this time,
The other cooler (18b) stops cooling operation, and the suction port (
10) Off-cycle defrosting is performed using the amount of heat held by the circulating air from 10) as the heat source for static elimination. In addition, the protective air suction port (
The air sucked in from 11) is sent to the protective air outlet (9) by the blower (13) and circulated.

By the way, the conventional operation control method, as shown in Fig. 3,
Close the solenoid valve (21a) of one cooler (18a) (
The timer control device (23) simultaneously switches the solenoid valves (21a>(2l b)) so that the solenoid valve (2'lb) of the other cooler (18b) opens (or closes) at the same time The cooling operation of the coolers (18a) (18b) was alternately interrupted to defrost the air.For this reason, when the solenoid valves (21a) (2l b) are switched simultaneously, the cooling operation of the coolers (18a) (18b) is interrupted. As a result, a hunting phenomenon may occur in the refrigeration cycle, or even if one solenoid valve (21a) (or 21b) closes, the other solenoid valve (21b) (or 21a) may not open at the same time. However, due to the difference in the timing of opening and closing the solenoid valve and the heat capacity of the coolers (18a) (18b), it takes time to reach the specified cooling capacity, and as a result, when switching the solenoid valve, the storage compartment (4) There is a risk that the internal temperature will rise, which may impede the quality maintenance of the cooled product.

[Purpose of the invention]

The purpose of the present invention is to eliminate the disadvantages of the conventional example, to obtain a stable refrigeration cycle, to reliably prevent the temperature inside the refrigerator from rising when the solenoid valves of the two coolers are switched, and as a result, to reduce the temperature of the products to be cooled. An object of the present invention is to provide a method for controlling the operation of a frozen/refrigerated open showcase that can maintain quality.

[Key points of the invention]

However, according to the present invention, the purpose of the lever is to provide a cold air circulation duct that forms an air curtain inside the showcase body, to arrange two coolers in the duct, and to open and close the cooler on the upstream side of each cooler. In a refrigerator/freezer open showcase equipped with a solenoid valve that switches between cooling operation and defrosting operation, the solenoid valve of one cooler is opened slightly before the solenoid valve of the other cooler closes. achieved.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings.

Note that the refrigerated/refrigerated open showcase used in the operation control method of the present invention is the same as that described with reference to FIGS. 1 and 2, so detailed description thereof will be omitted.

The method of controlling the operation of a refrigerated open showcase of the present invention is performed by alternately opening and closing the solenoid valves (21a) and (21b). Shortly before one solenoid valve (21a) (or 21b) closes, for example, for a time long enough to sufficiently cool the inside of the refrigerator, the other solenoid valve (21b) (or 21a) is closed.
) is set in the timer control device 23 so that it opens.

In this way, when the solenoid valves (21a) and (2l b) are open, the coolers (18a and 18b) perform a cooling operation, and when they are closed, the cooling operation is stopped and off-cycle defrosting is performed.
Now, the solenoid valve (2'la) opens and the solenoid valve (2l b) opens.
When the refrigerant is closed, the refrigerant sent from the condensing unit (22) flows through the expansion valve (2a), the refrigerant liquid pipe (19a), and the condensing unit (22) from the condenser (18a again). A refrigeration cycle is formed here and the cooler (18a)
is in cooling operation, and the air sucked in from the suction port (10) is cooled by the cooler <18a) and then blown out from the blowout port (8) to form a cold air curtain and close the opening (2). do. At this time, the air sucked into the protective air circulation duct (7) is blown out from the outlet (9) by the blower (13) to form a protective air curtain outside the cold air curtain.

On the other hand, no refrigerant flows through the cooler (18b), so the cooling operation is interrupted, and off-cycle defrosting is performed in which the heat quantity of the air blown by the blower (12) is used as the heat source for defrosting.

Next, after a predetermined period of time has elapsed, the solenoid valve (2l b) opens, but at this time the already open solenoid valve (21a) continues to be open, so the refrigerant is transferred to the cooler (18a) and the cooler (18b).
Both of the two coolers (18a) and (18b) are in cooling operation.

Then, after a further predetermined period of time has elapsed, the solenoid valve (2
1a) is closed and only the solenoid valve (2l b) is open, so the cooler (18b) continues its cooling operation, but no refrigerant flows into the cooler (18a) and the cooling operation is interrupted. Off-cycle defrosting is performed in which the amount of heat held by the air blown by the blower (12) is used as the defrosting heat source.

In this way, by cooling the inside of the case with one of the coolers while the other cooler is defrosting, cooling and defrosting can be performed simultaneously without interrupting cooling. ) (or 18b) solenoid valve (21a)(
or 21b) closes and starts defrosting operation, the solenoid valve (21b)' (or 21a) of the other cooler (18b) (or 18b) opens and starts cooling operation, so during this time, the two The cooling operation of the coolers (18a) and (18b) wraps, and the inside of the refrigerator is rapidly cooled.

In this way, as shown in FIG.
When operating 18b), the cooling capacity (Q2) at the evaporation temperature (ET2) that is balanced with the condensing unit is obtained, and the cooling capacity (Ql) when operating one cooling pipe is obtained at the evaporation temperature (ETl) that is balanced with the condensing unit. Since the temperature is lower than the evaporation temperature (ET2) when two coolers are operated, the cooling capacity is approximately 80% of the cooling capacity (Q2) when two coolers are operated.

Therefore, even if one cooler is operated, the inside of the storage is already sufficiently cooled by two coolers, so the cooling capacity does not decrease much compared to when two coolers are operated. ) The rise in internal temperature is slight.

In this embodiment, a showcase is used in which the coolers (18a) and (18b) are installed in the front and back direction of the cold air circulation duct (6), but the upper and lower parts of the cold air circulation duct (6) are Alternatively, a cooler may be provided in the cold air circulation duct and the protective air circulation duct, respectively. Further, in the non-embodiment, a frozen/refrigerated open showcase with a separate condensing unit (22) has been described, but the present invention may be applied to a frozen/refrigerated open showcase with a built-in condensing unit.

〔Effect of the invention〕

As described above, in the operation control method of the freezer/refrigerator open showcase of the present invention, after the interior of the refrigerator is sufficiently cooled by the cooling operation of the two coolers, the cooling operation of the one cooler (5) is started.
Even if other coolers stop operating and start defrosting, the temperature inside the refrigerator does not rise and the quality of the products in the refrigerator can be maintained.

Also, when one cooler goes into cooling operation, the other cooler is in cooling operation, so the pressure change in the cooler is small.
Furthermore, even if there is a slight deviation in the timing of opening and closing the electromagnetic valve, the effect on the refrigeration cycle is small, so a stable refrigeration cycle can be obtained.

[Brief explanation of drawings]

Figure 1 is a longitudinal side view of a frozen/refrigerated open showcase.
Fig. 2 is a refrigerant circuit diagram of the same as above, Fig. 3 is a time chart showing conventional operation, Fig. 4 is a time chart showing an embodiment of the method of the present invention, and Fig. 5 is a diagram of the original operation. 11 is a graph showing the cooling capacity when one condensing unit and cooler is in operation and when two coolers are in operation. (1)... Open showcase body (2)... Opening ( 3)...Duct board (4)...Product storage
(5)...Duct plate (6)...Cold air circulation duct I-(
7)...Protective air circulation duct (8)...Cold air blowout n
(9)...Protective air outlet (10) (1,1)
...Suction port (12) (13) ...Blower (16)
---Ku 搏j treatment (]7a) (17b) ---
・Passage (18a) (181))...Cooler (1)
9a) (19b)---Refrigerant/lk'tW(
20a) (20b) - Expansion valve (21a) (
21b) - Solenoid valve (22)...Condensation unino l-(
23) ...Timer control device agent Patent attorney Masu Ohone

Claims (1)

[Claims] A cold air circulation duct that forms an air curtain is provided inside the syzzy case body, and two coolers are installed within the duct, and a solenoid valve that opens and closes to switch between cooling operation and defrosting operation is installed on the upstream side of each cooler. 1. A method for controlling the operation of a freezer/refrigerator open showcase, characterized in that the solenoid valve of one cooler is opened slightly before the solenoid valve of the other cooler is closed.