JPH04283384A - Cold air circulation type open showcase - Google Patents

Abstract

PURPOSE:To perform a proper keeping of a heat capacity of defrosting hot air according to the variation of surrounding temperature and to prevent the temperature in a storing space from being increased by a method wherein a cold air circulation type open showcase is provided with a temperature sensor for sensing the surrounding temperature and a control means for outputting a signal for changing the heat capacity of a defrosting heater according to the output of the temperature sensor. CONSTITUTION:A control means CL22 opens an accessory contact point 22a according to the output of a temperature sensor in the case that the surrounding temperature is higher than a predetermined temperature A, and the control means CL22 opens a reversing circuit of a fan 10. In concurrent with this operation, the control means CL22 opens an accessory contact point (b), turning off a partial heater 20b of a defrosting heater 20 and reduces the operating capacity of the defrosting heater 20. In opposition to the above, in the case that the surrounding temperature is lower than a predetermined temperature B, the control means CL22 closes an accessory contact point 22c, turns on a partial heater 20c of the defrosting heater 20 so as to increase the operating capacity of the defrosting heater 20. With such an arrangement, the heat capacity at the defrosting temperature is kept at a proper value irrespective of a value of the surrounding temperature and then the temperature of the storing space is prevented from being excessively increased.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention has an opening on the front surface, and the cool air flow blown out from the outlet facing the opening allows
This invention relates to a cold air circulation type open showcase used for keeping food cold, in which an air curtain is formed in the opening and the storage space is cooled, and in particular, the cooler is improved to defrost appropriately depending on the ambient temperature. related to what was done.

0002

2. Description of the Related Art A cold air circulation type open showcase of this type is shown in FIG. 4 and is known. In Figure 4,
The main case 1 has a substantially U-shaped cross section with an opening 1a on the front, and consists of an outer box 2 made of a heat insulating wall and an inner box 3 that forms a storage space 4 inside. A partition plate 5 is provided between the inner box 3 and the inner box 3 to form two layers of cold air curtain ventilation passage 6 and protection air curtain ventilation passage 7. The cold air curtain ventilation passage 6 has its upper and lower ends facing the opening 1a, and has an outlet 6a and an inlet 6b, respectively.
A fan 8 and a cooler 9 to which refrigerant is supplied from a refrigeration unit (not shown) via an expansion valve (not shown) are disposed inside. In addition, ventilation duct 7 for protective air curtain
has its upper and lower ends facing the opening 1a, and has an air outlet 7, respectively.
a and a suction port 7b, and a fan 10 is disposed inside. Reference numeral 11 represents an air conditioner attached to the air outlet 6a and the air outlet 7a, 12 represents a shelf that partitions the storage space 4 into upper and lower levels, and 13 represents a base.

[0003] In the aforementioned open showcase, a large number of products are displayed and stored in the storage space 4. Then, the air in the storage space is circulated through the cold air curtain ventilation path 6 as shown by the solid arrow by the fan 8 that rotates in the normal direction, and is cooled by the cooler 9 to become cold air and sent to the outlet 6a. This cold air is blown out from the outlet 6a to form a cold air curtain 14. In addition, by the fan 10 rotating in the normal direction, non-cooled air circulated through the protective air curtain ventilation path 7 as shown by the solid arrow is blown out from the air outlet 7a to form the protective air curtain 15, and cool air is generated to enhance the heat shielding effect. Protects the air curtain 14. Therefore, the products in the storage space 4 are efficiently cooled and kept cold.

Next, the case of defrosting operation will be explained. During the above-mentioned cold storage operation, the cold air curtain 14 and the protective air curtain 15 draw in some outside air midway through the inlets 6b and 7.
flows to b. This outside air has moisture, so if the cold storage operation continues, the moisture contained in the outside air will be transferred to the cooler 9.
Frost gradually forms on the surface of the cooler 9, and the cooling capacity of the cooler 9 decreases. For this reason, in the open showcase, a defrosting operation for removing the frost is performed at appropriate intervals using a timer or the like. As illustrated in FIG. 5, the auxiliary power supply is connected to a timer 16 having an auxiliary contact 16a that closes when activated, and a thermostat switch (TS(1)) 17 for detecting the defrosting end point that has an auxiliary contact 17a that opens when activated. has been done. The auxiliary contact 16a and the auxiliary contact 17a are connected in series with each other and then connected in series with the relay 18 to supply auxiliary power. When timer 16 operates, auxiliary contact 1
6a is closed, and the auxiliary contact 17a is closed, so it conducts to the relay 18, the auxiliary contact 18a of the relay 18 is switched to the reverse side, the auxiliary contact 18b is opened, and the auxiliary contact 18c is closed, respectively. The fan 10 is rotated in the reverse direction, the operation of the refrigeration unit 19 that supplies refrigerant to the cooler 9 is stopped, and the defrost heater 20 installed upstream of the cooler 9 is energized to start defrosting operation. enter. At this time, the fan 8 disposed in the cold air curtain ventilation path 6
continues to run in the forward direction.

As shown by the chain arrow in FIG. 4, as the fan 10 rotates in reverse, outside air that is warmer than the air in the storage space is sucked into the protective air curtain ventilation path 7 from the air outlet 7a. This outside air is sucked into the cold air curtain ventilation path 6 from the suction port 6b and flows as shown by the chain arrow. Then, it is further heated by the defrosting heater 20 to become defrosting hot air, which washes and warms the cooler 9 to melt and remove the frost. During the defrosting operation, the amount of heat for melting and removing the frost on the cooler 9 is given by the amount of heat possessed by the warm outside air and the electric power applied to the defrosting heater 20. When the frost on the cooler 9 is removed by the defrosting operation, the temperature of the defrosting hot air, which has been cooled by the frost and has decreased, increases and is switched to the thermostat switch (TS(1).
)) is detected at 17, auxiliary contact 17a is opened, and relay 1 is activated.
8 is stopped, the auxiliary contact 18a of the relay 18 is switched to the forward rotation side, the auxiliary contact 18b is closed, and the auxiliary contact 18c is opened, thereby ending the defrosting operation and returning to the cold storage operation.

[0006]

[Problems to be Solved by the Invention] By the way, in conventional open showcases, the start of defrosting operation is carried out according to the defrosting operation cycle determined by a timer, etc., and the operating conditions during this defrosting operation are It is set according to the standard condition. However, under such defrosting operating conditions, it is not always possible to appropriately respond to changing environmental conditions in open showcases that are operated throughout the year. For example, when the ambient temperature is high, the cold air curtain is disturbed by the reverse rotation of the fan installed in the ventilation path for the protective air curtain, causing an excessive amount of heat to enter the storage space from the outside air. The temperature of the space will rise excessively. For example, when the ambient temperature is low, the amount of heat held by the defrosting warm air is insufficient, so even if the thermostat switch to end defrosting is activated, frost remains in the cooler, and the cold storage operation starts. As the amount of frost increases, it eventually becomes excessive and the temperature of the storage space increases. An increase in the temperature of the storage space raises the temperature of the products in the storage space, which may reduce the freshness of the products, so solving this problem has been an issue.

The present invention was developed in view of the problems of the prior art described above, and its purpose is to appropriately adjust the amount of heat of the defrosting warm air that melts the frost in the cooler depending on the ambient temperature. To provide a cold air circulation type open showcase that prevents the temperature of a storage space from rising excessively.

[0008]

[Means for Solving the Problems] The above-mentioned objects of the present invention are as follows:

1) A main body case having an opening on the front and a storage space inside the opening and having a substantially U-shaped cross section, and a cold air curtain in the opening; A plurality of ventilation channels are provided inside the main body case to form a protective air curtain on the outside of the main body case, and the upper and lower ends thereof face the opening to form a blowout port and a suction port, respectively; In a cold air circulation type open showcase comprising a cooler, a fan, and a defrosting heater arranged in a ventilation passage, and a fan arranged in the ventilation passage for a protective air curtain,
A temperature sensor for detecting ambient temperature; and a control means for outputting a signal for changing the operating capacity of the defrosting heater according to the output of the temperature sensor;

2) A main body case having an opening in the front and a storage space inside the opening and having a substantially U-shaped cross section, and a cold air curtain in the opening; A plurality of ventilation channels are provided inside the main body case to form a protective air curtain on the outside of the main body case, and the upper and lower ends thereof face the opening to form a blowout port and a suction port, respectively; In a cold air circulation type open showcase comprising a cooler, a fan, and a defrosting heater arranged in a ventilation passage, and a fan arranged in the ventilation passage for a protective air curtain,
a temperature sensor that detects ambient temperature; a signal that changes the operating capacity of the defrosting heater according to the output of the temperature sensor; and a signal that changes the operation of the fan disposed in the ventilation path for the protective air curtain. and a control means for outputting the

3) In the means described in item 1 or 2 above, the control means is achieved by a thermostat switch having an ambient temperature detection function.

0012

[Function] A temperature sensor that detects the ambient temperature, a signal that changes the capacity of the defrosting heater according to the output of this temperature sensor, and a signal that changes the operation of the fan installed in the ventilation path for the protective air curtain. By being equipped with a control means that outputs The amount of heat that the hot air has is suppressed to an appropriate value, and the disturbance imparted to the cold air curtain is also reduced. For example, when the ambient temperature becomes low, the operating capacity of the defrosting heater is increased compared to the standard state, and the fan is reversed or stopped, so that the heat amount of the defrosting hot air is adjusted to an appropriate value. The amount will be increased to

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of a cold air circulation type open showcase according to an embodiment of the present invention, in which (a) is a sectional view, and (b) is a cross-sectional view.
) is a control circuit diagram. Components that are the same as those in the conventional example shown in FIGS. 4 and 5 are designated by the same reference numerals, and their explanations will be omitted. In FIG. 1, 21 is a temperature sensor that detects the ambient temperature and provides its output to control means (CL) 22. Control means (C
L) 22 is, for example, a temperature responsive control device, and when the ambient temperature is above a predetermined temperature (A), the attached contact 22a is opened to open the reverse circuit of the fan 10, and the attached contact 22b is opened. The circuit is opened to open the partial heater 20b of the defrosting heater 20 to reduce the operating capacity of the defrosting heater 20, and when the ambient temperature is below a predetermined temperature (B), the attached contact 22c is closed to defrost. The partial heater 20c of the heater 20 is turned on to increase the operating capacity of the defrosting heater 20. With this configuration, for example, during defrosting operation when the ambient temperature is high, the operating capacity of the defrosting heater 20 is reduced and the fan 10 is not reversed.
The heat amount of the defrosting hot air is suppressed to an appropriate amount, and the disturbance applied to the cold air curtain is reduced. This prevents the temperature of the storage space 4 from becoming excessive. In addition, during defrosting operation when the ambient temperature is low, the operating capacity of the defrosting heater 20 is increased compared to the standard state to increase the amount of heat of the defrosting hot air to an appropriate amount. The frost adhering to the cooler 9 can be reliably melted before the termination thermostat switch (TS(1)) 17 is activated.

Next, different embodiments of the present invention will be explained. FIG. 2 is a configuration diagram of a cold air circulation type open showcase according to a different embodiment of the present invention, in which (a) is a sectional view and (b) is a control circuit diagram. An embodiment of the present invention in FIG. 1 and FIG.
Components that are the same as those in the conventional example shown in FIG. 5 are given the same reference numerals, and their explanations will be omitted. In FIG. 2, reference numeral 23 has an ambient temperature detection function, and when the ambient temperature is higher than a predetermined temperature (A), an attached contact 23a is opened to open the reverse circuit of the fan 10, and an attached contact 23b is opened to defrost the air. This is a thermostat switch (TS(2)) that opens the partial heater 20b of the heater 20 to reduce the operating capacity of the defrosting heater 20. 2
4 has an ambient temperature detection function and the ambient temperature reaches a predetermined temperature (B
) In the following cases, the attached contact 24a is closed and the defrosting heater 2 is turned on.
Thermostat switch (TS(3)) that turns on the partial heater 20c of 0 to increase the operating capacity of the defrosting heater 20.
). With such a configuration, for example, during defrosting operation when the ambient temperature is high, the defrosting heater 20
By reducing the operating capacity of the fan 10 and not rotating the fan 10 in reverse, the amount of heat of the defrosting warm air is suppressed to an appropriate amount, and the disturbance applied to the cold air curtain is reduced. This prevents the temperature of the storage space 4 from becoming excessive. Also, during defrosting operation when the ambient temperature is low,
By increasing the operating capacity of the defrosting heater 20 compared to the standard state and increasing the heat amount of the defrosting hot air to an appropriate amount,
Thermostat switch 17 (TS(1)) for ending defrosting
The frost adhering to the cooler 9 can be reliably melted by the time the cooler is activated.

FIG. 3 shows the temperature of the storage space 4 mainly during defrosting operation in the case of the embodiment according to the present invention, in comparison with the case of the conventional example, and the case where the ambient temperature condition is high. A graph of changes over elapsed time is shown. In the graph, the vertical axis shows the storage space temperature, the horizontal axis shows the elapsed time, the solid line shows the case according to the present invention, and the dotted line shows the case of the conventional example. First, in the case of the conventional example, the cold storage operation is switched to the defrosting operation at time t0, the refrigeration unit 19 is stopped, the defrosting heater 20 is turned on, and the fan 10 is reversed to disturb the cold air curtain and store the cold air from the outside air. space 4
As the amount of heat entering increases, the defrosting of the cooler 9 is completed and the temperature of the defrosting hot air on the downstream side of the cooler 9 rises.
At the time when the thermostat switch (TS(1)) 17 is activated to return to the cold storage operation, the temperature of the storage space 4 increases significantly. By the way, in the case of the embodiment according to the present invention, the cold storage operation is switched to the defrost operation at time t0, the refrigeration unit 19 is stopped, and the defrost heater 20 is turned on, which is the same as in the conventional example, but the above-mentioned As the operating capacity of the defrosting heater 20 is reduced and the fan 10 is stopped, the heat amount of the defrosting warm air is suppressed to an appropriate value, and the disturbance given to the cold air curtain is also reduced. As a result, the defrosting of the cooler 9 is completed and the temperature of the hot air for defrosting on the downstream side of the cooler 9 rises, and at t2, the thermostat switch (TS(1)) 17 is activated to enter cold storage operation. The degree of rise in the temperature of the storage space 4 at the time of return is reduced compared to the conventional example, and the time during which the temperature remains relatively high is also shortened.

In the above description, it was assumed that the fan 10 disposed in the protective air curtain ventilation path 7 is stopped when the ambient temperature is high during defrosting operation, and is reversed under other ambient temperature conditions. It may be stopped even under ambient temperature conditions of 1000, or may be reversed only when the ambient temperature is low. In the former case, the auxiliary contact 18a is just a switching contact,
In the latter case, for example, assuming the embodiment shown in FIG. It shall also be provided with an attached contact for opening the 10 reversing circuits. Further, in the above description, the operating capacity of the defrosting heater 20 is switched in three stages depending on the ambient temperature conditions, but it may be switched in two stages. In this case, for example, assuming the embodiment shown in FIG. 1, the partial heater 20c of the defrosting heater 20 and the attached contact 22c of the control means (CL) 22 may not be installed.

[0017]

Effect of the invention: A temperature sensor that detects the ambient temperature, a signal that changes the capacity of the defrosting heater according to the output of this temperature sensor, and a fan installed in the ventilation path for the protective air curtain as needed. Equipped with a control means that outputs a signal to change the operation, when the ambient temperature is high, the operating capacity of the defrosting heater is reduced compared to the standard state, and the fan is stopped, so that warm air for defrosting is reduced. The storage space 4 during defrosting operation is suppressed to an appropriate value, and the disturbance given to the cold air curtain is also reduced.
In addition, when the ambient temperature is low, the operating capacity of the defrost heater can be increased compared to the standard state and/or the fan can be rotated in reverse to lower the defrost temperature. By increasing the amount of heat carried by the wind to a more appropriate value than under standard conditions, frost will not remain in the cooler, and therefore the temperature in the storage space will not rise. This has the effect that the temperature of the product in the storage space does not increase and the freshness of the product does not decrease.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a cold air circulation type open showcase according to an embodiment of the present invention, in which (a) is a sectional view and (b) is a control circuit diagram.

FIG. 2 is a configuration diagram of a cold air circulation type open showcase according to a different embodiment of the present invention, in which (a) is a sectional view and (b) is a control circuit diagram.

[Figure 3] Graph showing changes in the temperature of the storage space over time

[Figure 4] Cross-sectional view of a conventional cold air circulation type open showcase

[Figure 5] Control circuit diagram of a conventional open showcase with cold air circulation

[Explanation of symbols]

6. Ventilation duct for cold air curtain 7 Ventilation duct for protective air curtain 8 Fan 9 Cooler 10 Fan 20 Defrost heater 20b Partial heater 20c Partial heater 21 Temperature sensor 22 Control means 23 Thermostat switch 24 Thermostat switch

Claims (3)

[Claims] 1. A main body case having an opening on the front and a storage space inside the opening and having a substantially U-shaped cross section; a cold air curtain provided in the opening; A plurality of ventilation channels are provided inside the main body case to form a protective air curtain on the outside of the main body case, and the upper and lower ends thereof face the opening to form a blowout port and a suction port, respectively; Detecting ambient temperature in a cold air circulation type open showcase comprising a cooler, a fan, and a defrosting heater arranged in a ventilation passage, and a fan arranged in the ventilation passage for a protective air curtain. A cold air circulation type open showcase comprising a temperature sensor and a control means for outputting a signal for changing the operating capacity of the defrosting heater according to the output of the temperature sensor. 2. A main body case having a substantially U-shaped cross section with an opening on the front and a storage space inside the opening, and a cold air curtain provided in the opening. A plurality of ventilation channels are provided inside the main body case to form a protective air curtain on the outside of the main body case, and the upper and lower ends thereof face the opening to form a blowout port and a suction port, respectively; In a cold air circulation type open showcase comprising a cooler, a fan, and a defrosting heater arranged in a ventilation passage, and a fan arranged in the ventilation passage for a protective air curtain, the ambient temperature is detected. a sensor, and a control means for outputting a signal for changing the operating capacity of the defrosting heater and a signal for changing the operation of the fan disposed in the ventilation path for a protective air curtain in accordance with the output of the temperature sensor. An open showcase with cold air circulation. 3. The cold air circulation type open showcase according to claim 1 or 2, wherein the control means is a thermostat switch having an ambient temperature detection function.