JPH0235225B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a control device for a rapid freezing device in which a direct cooling type auxiliary cooler is provided in a part of the freezer compartment of a forced draft type refrigerator-freezer.

Conventional structure and its problems Traditionally, in this type of quick freezing equipment,
During quick freezing, the compressor of the refrigeration cycle is operated continuously, but the quick freezing effect depends on whether the forced draft fan is operated or stopped depending on the temperature range of the freezing process. That is, there is a choice between operating the blower and giving priority to increasing the amount of heat exchange through forced convection, or stopping the blower and lowering the evaporation temperature of the direct cooler to give priority to increasing the temperature difference between the product and the product. However, during quick freezing, the most common method for instructing the fan to operate or stop is to divide the quick freezing time into predetermined periods and switch between them, but in this case there is no correlation with the product temperature. The control method is rough. Another main method is to use a temperature detection device that indirectly detects the temperature of the article, but in this case as well, a certain temperature at which the blower starts and stops is set and control is performed based on this temperature. However, the temperature to be commanded differs depending on the size, type, etc. of the stored articles, which has the disadvantage of lacking in versatility.

OBJECTS OF THE INVENTION In view of the above points, an object of the present invention is to provide a control device that most efficiently operates and stops a forced draft fan during rapid freezing.

Structure of the Invention In order to achieve this object, the freezing temperature gradient of the article being rapidly frozen is detected, and the operation and stop of the blower is controlled depending on the presence or absence of the gradient.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

In the figure, reference numeral 1 denotes a refrigerator body, which is divided by a partition wall 2 into a freezer compartment 3 at the top and a refrigerator compartment 4 at the bottom. Further, a quick freezing chamber 5 is provided within the freezing chamber 3, and a damper thermostat 6 is provided at the entrance of the refrigerating chamber 4 to adjust the amount of cold air inflow.

7 is a compressor of the refrigeration cycle, 9 is a condenser, 9 is a first capillary tube, and 10 is a main cooler, each of which is connected in a ring with piping to constitute a refrigeration cycle. Here, it is assumed that the main cooler 10 is housed within the partition wall 2. Further, 11 is a second capillary tube for quick freezing, 12 is a direct cooling type auxiliary cooler provided in a part of the quick freezing chamber 5, and a flow path connecting the two in series is connected to the first capillary tube 9. connected in parallel. 13 is a flow path switching valve that switches the flow path to the first capillary tube 9 and the flow path to the second capillary tube 11.
Reference numeral 14 is a forced ventilation blower installed in the compartment 2, which sends low-temperature cold air generated in the main cooler 10 to the freezer compartment 3.
and the refrigerator compartment 4 via the damper thermostat 6.
It is something that is sent inside.

Next, the electric circuit and control circuit will be explained.

First of all, regarding the electric circuit, compressor 7 is relay 1
The blower 14 is connected to a power source via a relay 16, and is connected in series with a relay 16 and then in parallel with a compressor 7. Further, the flow path switching valve 13 is connected in series with the relay 17 and then connected in parallel with the power source. However, this flow path switching valve 13 is configured to switch to the normal flow path when the excitation coil is not conductive, and to switch to the quick freezing flow path when the excitation coil is conductive. Here, the relay 15 is configured to close its contacts when the excitation coil is energized, the relay 16 is configured to open its contacts when the excitation coil is energized, and the relay 17 is configured to close its contacts when the excitation coil is energized.

Next, the control device that drives these relays will be described. Reference numeral 18 is a temperature control device that includes a thermistor 19, resistors R ₁ , R ₂ , R ₃ , and
It is composed of a comparator 20. The output of the comparator 20 is configured to send a signal to turn on/off the relay 15 via an OR circuit 21 by a driver circuit (not shown) such as a transistor.

22 is a quick freezing switch, and 23 is a quick cooling time timer. The rapid cooling timer 23 is configured to continue outputting an "H" signal during a predetermined rapid cooling period after the rapid freezing switch 22 is turned on. One of the outputs of the rapid cooling timer 23 is connected to the OR circuit 2.
1, one side is connected to send a signal to turn on/off the relay 17, and further
It is also connected to the input of the AND circuit 24. 25
26 is a thermistor installed in a part of the quick freezing chamber 5 to represent temperature changes of stored items;
2 is a temperature gradient detection device that stores the temperature change (resistance change) of the thermistor 25 to detect a freezing temperature gradient, and 27 is a reference gradient generation device to which the temperature gradient detection device is compared. 28 is a comparator which compares the output of the temperature gradient detection device 26 and the reference gradient of the reference gradient generator, and when they match within a certain variation range, outputs a predetermined output, "H" or "L". ” occurs. The output of the comparator 28 is connected to the AND circuit 24, and is configured to send a signal to turn the relay 16 ON/OFF via this.

Next, the operational status of this configuration will be explained.
Normally, if the internal temperature of the refrigerator (freezer compartment temperature) is higher than the predetermined value, the resistance value of the thermistor 19 R _TH
has become smaller, so R _TH and R ₁ of the temperature control device 18
Since the potential at point A determined by is higher than the potential at point B determined by resistors R ₂ and R ₃ and the output of comparator 20 becomes "H", the output of CR circuit 21 also inevitably becomes "H". Then, the relay 15 is turned on via a driver circuit such as a transistor (not shown), and the compressor 7 is operated. At this time, the quick-freezing switch 22 is in the OFF state, so the quick-cooling timer 23
Since the output of the AND circuit 24 is "L", the output of the AND circuit 24 is also "L", and the relay 16 is turned on, that is, the blower 14 is operated. Also, since the relay 17 is turned off by the output "L" of the quenching timer 23 and the flow path switching valve 13 is in a non-conducting state, the refrigerant circuit is as follows: compressor 7 → condenser 8 → first capillary tube 9 →
Cooling is performed by configuring a normal cycle of main cooler 10→compressor 7. After that, when the inside of the refrigerator is cooled to a certain temperature, the resistance value RTH of the thermistor 19 increases, and the A _potential becomes smaller than the B potential, so the output of the comparator 20 becomes "L".
Together with the “L” signal from the quenching timer 23
The output of the OR circuit 21 also becomes "L", so the relay 15 is turned off and the compressor 7 and blower 14 are stopped. Thereafter, this action is repeated to perform the normal cooling action.

Next, we will discuss the operating conditions during rapid freezing. When performing quick freezing, optionally turn on quick freezing switch 2.
2 is turned on, the output of the quenching timer 23 becomes "H", the output of the OR circuit 21 becomes "H" regardless of the output of the temperature control device 18, and the compressor 7 is first forcedly operated. At the same time, the relay 17 is turned on by the "H" signal of the quenching timer 23, and the flow path switching valve becomes conductive, and the refrigerant circuit goes from compressor 7 to condenser 8 to second capillary tube 11 to auxiliary cooler 12 to main cooling. The flow path is switched from the container 10 to the compressor 7 for rapid freezing, and the refrigerant is flowed into the auxiliary cooler 12 to start the rapid freezing action. And the O of blower 14 during quick freezing.
For N/OFF control, the output of the comparator 28 is “H”,
Determined by “L”. That is, comparator 2
When the output of the AND circuit 24 is "H", the relay 16 is turned off and the blower 14 is turned off.
stops. Conversely, when the output of the comparator 28 is "L", the relay 16 is turned on and the blower 14 is turned on.
is driven. Here, “H” of the comparator 28,
To determine the "L" output, a thermistor 25 provided in a part of the quick freezing chamber 5 detects temperature changes due to freezing of stored items, and a temperature gradient detection device 26
When the temperature drop gradient is inputted and stored in the reference gradient generator 27, the temperature drop gradient is compared with a reference gradient defined in the reference gradient generator 27 each time, and the gradient is kept within a certain range with respect to the reference gradient. For example, by generating a predetermined output signal "H" or "L", the blower can be controlled to operate or stop as described above. In other words, as shown in the figure, the temperature transition of an article during rapid freezing is such that in section A, from the initial temperature T ₁ °C to around the freezing temperature T ₂ °C, the article is cooled with a steep temperature gradient. Temperature zone B
In the section (near T ₂ ℃), since the cooling effect is applied to latent heat removal, there is almost no temperature gradient, and the temperature remains almost horizontal. When the cooling actually progresses and freezing is completed, the freezing temperature varies depending on the article being cooled, with a temperature gradient again in section C until reaching the final temperature T ₃ °C, ranging from T ₁ °C to T ₂ °C to T ₂ °C.
There is a relatively clear temperature gradient between T ₃ °C and freezing temperature, and there is no gradient near the freezing temperature of T ₂ °C, and the temperature changes in a nearly horizontal state.The present invention focuses on this characteristic. Therefore, it is possible to classify each temperature zone depending on the presence or absence of a temperature gradient, and to control the operation and stop of the blower individually for each zone.

For example, the freezing temperature zone T that determines the effectiveness of quick freezing
In this section, depending on the item to be frozen, the blower 14
The difference is whether it is better to drive or stop. In other words, if the shape of the article is relatively flat and thin, the contact with the auxiliary cooler 12 is good, so the blower 14 is stopped to reduce the amount of heat exchanged with the air inside the refrigerator. It is preferable to increase the freezing ability by lowering the temperature of the cooler 12 and increasing the temperature difference between the cooler 12 and the article. On the other hand, if the product has an irregular shape and a large capacity, the blower 1
By operating No. 4, the amount of heat exchange is increased due to forced convection from the entire surface of the article, and the freezing ability is enhanced.

Next, for sections other than the freezing temperature zone T ₂ , T ₁ ~
Regarding the section T ₂ , it is desirable to select whether to operate or stop the blower 14 based on roughly the same concept as in the freezing temperature zone T ₂ described above. On the other hand, for the temperature range T ₂ to _{T 3} , a desirable method may be used to reach the freezing stable temperature as quickly as possible.

Effects of the Invention As is clear from the above description, the present invention provides a direct cooling type auxiliary cooler in the freezer compartment of a forced ventilation type refrigerator-freezer, and further provides forced ventilation for each temperature zone during the freezing process of articles during quick freezing. As a means for operating or stopping the blower, the blower is configured to be able to be commanded to be operated or stopped selectively depending on the degree of temporal gradient of the temperature detected by the temperature detection device that represents the temperature transition of the article. Therefore, it is possible to clearly distinguish between the period from the start of quick freezing to the freezing temperature, which has a large temperature gradient, and from after passing through the freezing temperature zone to the end of quick freezing, and the section of the freezing temperature zone, which has a small temperature gradient. Switching control can be performed when it is necessary to switch between operating and stopping the blower in these sections in order to improve the refrigeration capacity. Therefore, the time in the freezing temperature range can be shortened, without sacrificing the freshness of the product.
Can be rapidly frozen.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional structural diagram of a refrigerator showing an embodiment of the present invention, Fig. 2 is a piping diagram of its refrigeration cycle, and Fig. 3 is a sectional view of a refrigerator showing an embodiment of the present invention.
The figure is an electric circuit and control circuit diagram, and FIG. 4 is a time-temperature characteristic diagram during freezing of articles. 5... Rapid freezing chamber, 7... Compressor, 10... Main cooler, 12... Auxiliary cooler, 13... Flow path control device, 14... Blower, 19, 25... Thermistor.

Claims (1)

[Claims] 1 A main cooler provided in the cooling chamber, a blower that circulates the air cooled by the main cooler to the freezer compartment and the refrigerator compartment, and a compartment formed so that the air cooled by the main cooler passes through the freezer compartment. A quick freezing room,
a direct cooling type auxiliary cooler provided in the rapid freezing chamber; a flow path for controlling whether the refrigerant flows only to the main cooler or to both the main cooler and the auxiliary cooler; a control device; A temperature detection device is provided in a part of the auxiliary cooler in a thermally conductive manner to sense the temperature of stored items, and a compressor of the refrigeration cycle is operated continuously, and refrigerant is continuously flowed into the auxiliary cooler. Rapid freezing of a refrigerator, which performs quick freezing, and is equipped with a selection means for selecting operation or stop command of the blower according to the degree of temporal gradient of temperature detected by the temperature detection device during the quick freezing. Device.