JPS6157546B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention switches the temperature of cold air into the refrigerator as the lighting circuit opens and closes when the store opens, closes, etc.
This invention relates to a temperature control device for a low-temperature show case that reduces power consumption and appropriately controls the temperature of products.

Generally, a low-temperature display case in a supermarket or the like is a box for displaying products at a low temperature by cooling the inside of the insulated box using a refrigeration cycle. That is, as shown in FIG. 1, a cooler 2 consisting of an evaporator constituting a refrigeration cycle is provided at the bottom of an insulating box 1 with one side open.
A cold air flow path 5 is formed from the suction port 3 provided at the bottom of the fan 6 to the cooler 2, the inner back surface of the heat insulating box 1, and the discharge port 4 provided at the top of the heat insulating box 1.
As a result, the cold air cooled in the cooler 2 is circulated as shown by the arrow, and the cold air is supplied to the inside of the refrigerator 7. At the same time, an air curtain is placed in the opening of the heat insulating box 1 from the discharge part 4 to the suction port 3. It cools the products displayed on the product display shelves 8 and wire racks 9 in the warehouse 7, and maintains the products at a low temperature.
In addition, in the chamber 7, in order to enhance the display effect,
A fluorescent lamp 10 is provided near each shelf 8 and discharge section 4.

The required refrigerating capacity is determined for the low-temperature case, and a refrigerating machine consisting of a compressor, condenser, etc. corresponding to the required refrigerating capacity is built in. Generally, a thermostat controls the operating rate of the refrigerating machine, and Temperature control is performed. In other words, the operating rate is
It is the percentage of operating time of the refrigerator, and if the thermostat temperature setting is set lower, the operating rate will increase.
The products in compartment 7 cool well, and on the other hand, if you set the thermostat temperature high, the operating rate will decrease.
The temperature of the product becomes high. As shown in Fig. 2, the thermostat is connected to the thermostat main body 1.
1 is provided with a temperature setting knob 12 and one or more sets of output terminals 13, a temperature sensing tube 14 is connected to the thermostat main body 11 via a capillary tube 15, and the measured temperature detected by the temperature sensing tube 4 is connected to the thermostat main body 11 through a capillary tube 15. Tm
By comparing this with the set temperature Ts by the temperature setting knob 12, an "open" or "close" signal is output to the output terminal 13, and this signal causes the compressor of the refrigerator to be activated via the temperature control device inside the refrigerator 7. The electric motor is energized and de-energized, and the refrigerator is driven and de-energized. Therefore, since the thermostat main body 11 has a unique on/off temperature difference Td, an "open" signal is output to the output terminal 13 when Ts>Tm, and conversely, a "closed" signal is output to the output terminal 13. The signal is output when Ts+Td<
It's time for Tm.

Therefore, conventionally, a temperature control device for controlling the temperature of the inside of the refrigerator 7 has a temperature sensing cylinder 14 connected to a cold air flow path inside the discharge part 4, as shown in FIG.
The thermostat main body 11 is installed in the heat insulating box body 1.
A temperature setting knob 12 is provided on the reflector 16 at the upper front of the refrigerator and protrudes to the outside, allowing the set temperature Ts to be set to an arbitrary value.As shown in FIG. ing. That is, the electric motor 17 of the compressor of the refrigerator is connected to the three-phase power supply 20 via the overcurrent relay 19 and the contact 18' of the electromagnetic contactor 18, and the defrost timer contact 21,
A thermostat contact 11' opened and closed by the thermostat main body 11, an internal thermostat 22,
Overcurrent relay contact 9', high/low pressure switch 23
A series circuit of the magnetic contactor 18 and the electromagnetic contactor 18 is connected to two phases of the power supply 20 via a temperature-controlled contact switch 23.

Then, the temperature of the cold air is detected by the temperature sensing cylinder 14, and the detection signal is used to control the thermostat main body 1.
The "open" and "close" signals are output to the output terminal 13 of 1, and the thermostat contact 11' is closed and opened by the "open" and "close" signals, and the electromagnetic contactor 18 is energized or de-energized. The temperature inside the refrigerator 7 is controlled by opening and closing the contacts 18' of the electromagnetic contactor 18, energizing and de-energizing the electric motor 17, and driving and de-energizing the refrigerator.

By the way, in the conventional example, when used in a store such as a supermarket, when the store is closed such as at night when the store is not open for business, the lights in the low-temperature show case, that is, the fluorescent lights 10 are turned off at the same time as the store lights are turned off. Therefore, when the store is closed, the temperature of the products does not rise due to the heat generated by the fluorescent lights 10, but the temperature of the cold air detected by the thermosensor tube 14 is lower than that during business hours when the fluorescent lights 10 are on. As it is the same as when it opened,
When the store is closed, the temperature inside the refrigerator 7 will drop by the amount of temperature increase caused by the fluorescent light 10, causing the products to become too cold.
Not only is this undesirable from a product management perspective, but the operation rate of the refrigerator becomes higher than necessary, resulting in a waste of electricity.

With the above points in mind, this invention aims to reduce power consumption and appropriately manage the temperature of products by switching the temperature of cold air into the refrigerator as the lighting circuit opens and closes when the lighting circuit opens and closes. Next, this invention will be explained in detail with reference to FIG. 1 and the drawings from FIG. 4 showing an embodiment thereof. Note that the same symbols as above indicate the same thing.

First, FIG. 4 showing one embodiment will be explained.

In the conventional temperature control device shown in FIG. 3 in the low-temperature show case of FIG. 1, as shown in FIG. It is connected in series to a commercial power source 28 via a circuit switch 27, and a control circuit constituted by an electric heater 29 wound around the temperature sensing cylinder 14 is connected in series via the lighting circuit switch 27. Note that the switching contact is a thermostat contact 11'.

When the lighting circuit switch 27 is closed at the time of store opening, the lighting circuit 26 is energized, and
Since the electric heater 29 is energized, the electric heater 2
9, the temperature sensing cylinder 14 is heated, and the measured temperature Tm of the cold air in the temperature sensing cylinder 14 becomes higher than the cold air temperature by ΔT°C. In other words, the thermosensor tube 14 detects the cold air at an apparent temperature higher than △T°C, and as a result, the time it takes for the thermostat contact 11' to open becomes longer, and the thermostat body 11 detects the cold air at a lower set temperature. Temperature control, that is, a low temperature control state is achieved. Therefore, the set temperature of temperature setting knob 12
Ts is set higher than the temperature of cold air corresponding to the desired temperature inside the refrigerator 7 at the time of store opening by ΔT°C. When the store is closed, the lighting circuit switch 27 is opened, the lighting circuit 26 is de-energized, the electric heater 29 is de-energized, and the electric heater 29 no longer heats the temperature-sensitive tube 14. The measured temperature Tm becomes equal to the temperature of the cold air, and accordingly, the time until the thermostat contact 11' opens is shorter than in the low temperature control state, and the thermostat main body 11 is activated at a high set temperature. Temperature control, that is, a high temperature control state is entered. That is, the measured temperature Tm of the cold air in the thermosensor tube 14 is △T compared to when the store opened.
Since the temperature has dropped and the set temperature Ts of the temperature setting knob 12 is constant, the "close" signal output from the thermostat main body 11 decreases, and the operating rate of the refrigerator decreases.

Therefore, in response to the difference △T°C between the appropriate temperature of the chamber 7 at the time of opening and the appropriate temperature of the chamber 7 at the time of closing,
By setting the apparent measured temperature difference △T°C of the thermosensor tube 14 caused by the electric heater 29, it is possible to appropriately manage the temperature of products in the low-temperature show case in response to store openings and closings, that is, set temperature Ts in any case. The interior of the refrigerator can be maintained at the same temperature as a reference, and power consumption can be reduced.

Next, FIG. 5 showing another embodiment will be explained.

Similar to the embodiment described above, in the conventional temperature control device shown in FIG. 3 in the low temperature case of FIG. 1, the thermostat includes a step thermostat having a high temperature contact 30 for high temperature setting and a low temperature contact 31 for low temperature setting. Use the tatsuto to connect the switching contact.
A series circuit of the high temperature auxiliary contact 33 which is the b contact of the high temperature contact 30 and the auxiliary relay 32, and the low temperature contact 31
The control circuit is configured by the coil 35 of the auxiliary relay 32, and the changeover switch is connected to the defrost timer contact 21 and the parallel circuit. The lighting circuit 26 and the coil 35 of the auxiliary relay 32 are connected to the commercial power source 28 via the lighting circuit switch 27, respectively.

Then, the set temperature Th (Th = Ts + △T) of the thermostat main body 11 at which the high temperature contact 30 opens and closes,
The set temperature (Tl = Th) of the thermostat body 11, which opens and closes the low temperature contact 31, is set to the cold air temperature corresponding to the optimum temperature of the interior 7 of the refrigerator when the store is closed.
Set the cold air temperature corresponding to the optimum temperature of each.

Therefore, when the lighting circuit switch 27 is closed at the time of closing, the coil 35 of the auxiliary relay 32 is energized, so the coil 35 is activated, the high temperature auxiliary contact 33 is opened, and the low temperature auxiliary contact 34 is closed. The influence of opening and closing of the high-temperature contact 30 disappears, and the thermostat main body 11 enters a low-temperature control state based on the lower set temperature Tl, and energization and de-energization of the electromagnetic contactor 18 are controlled by opening and closing of the low-temperature contact 31. In other words, the temperature control inside the refrigerator 7 is based on the set temperature.
This is done based on Tl, and the temperature inside the refrigerator 7 is maintained at the optimum temperature at the time of opening.

Next, when the lighting circuit switch 27 is opened at the time of closing, the coil 35 of the auxiliary relay 32 is not energized, so the high temperature auxiliary contact 33 is closed, and
The low temperature auxiliary contact 34 opens and the thermostat body 1
1 is in a high temperature control state based on the higher set temperature Th, and energization and de-energization of the electromagnetic contactor 18 is controlled by opening and closing of the high temperature contact 30. That is, the temperature control of the inside of the refrigerator 7 is carried out based on the set temperature Th, which is the set temperature Ts of the temperature setting knob 12 and the apparent measured temperature difference ΔT°C added in advance, and the inside of the refrigerator 7 is controlled at the temperature when the store is closed. Maintained at optimal temperature (same temperature as when the store opened).

In the above embodiment, the high temperature contact 30 and the low temperature contact 31 were connected in parallel, but as shown in FIG. The auxiliary contact 36 is connected in parallel to the high temperature contact 30, and the high temperature contact 30 at the time of opening
The effects of the present invention can also be obtained by removing the effects of opening and closing.

As described above, according to the temperature control device for a low-temperature show case of the present invention, there is a lighting circuit switch that turns on and off a fluorescent lamp for lighting the interior of the refrigerator, and a lighting circuit switch that turns on and off a fluorescent lamp for lighting the interior of the refrigerator. and a thermostat for controlling the temperature inside the refrigerator which takes control states of two different high and low set temperatures, and the thermostat takes a low temperature control state of the lower set temperature when the lighting circuit switch is closed, and When the lighting circuit switch is opened, the high temperature control state is set to the higher set temperature.
When the store opens with the fluorescent lights on, the temperature inside the warehouse can be controlled at a low temperature that takes into account the heat generated by the fluorescent lights. At the same time, when the store closes and the fluorescent lights are turned off, the temperature inside the warehouse is controlled at a high temperature that eliminates the heat generated by the fluorescent lights. The temperature inside the warehouse can be controlled in a controlled state, and as a result, it is possible to prevent products from getting too cold when the store is closed, to achieve appropriate temperature control, and to reduce power consumption.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the low temperature case, Fig. 2 is a front view of the thermostat, Fig. 3 is a wiring diagram of a conventional temperature control device for a low temperature case, and Fig. 4 and the following drawings show the temperature of the refrigerating case of the present invention. Embodiments of the control device are shown, with FIG. 4 being a main part wiring diagram of one embodiment, FIG. 5 being a wiring diagram of another embodiment, and FIG. 6 being a partial wiring diagram of still another embodiment. 2... Cooler, 5... Cold air flow path, 7... Inside the refrigerator, 11... Thermostat body, 14... Temperature sensing tube, 17... Electric motor, 18... Magnetic contactor, 1
8'... Contact, 20... Power supply, 26... Lighting circuit, 27... Lighting circuit switch, 28... Power supply,
29...Electric heater, 30...High temperature contact, 31...
...Low temperature contact, 33, 34, 36...Auxiliary contact, 3
5...Coil.

Claims (1)

[Claims] 1. A lighting circuit switch that turns on and off a fluorescent lamp for lighting the interior of the refrigerator, and an interior temperature control that takes control of two different high and low set temperatures based on the open and closed states of this lighting circuit switch. and a thermostat, the thermostat being in a low temperature control state with a lower set temperature when the lighting circuit switch is closed, and being in a high temperature control state with a higher set temperature when the lighting circuit switch is opened. Temperature control device for low-temperature case.