JPS6196382A - Defrostation controller - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a defrosting control device configured to defrost a cooler such as a refrigerator without fail. .

(b) Conventional technology A conventional defrosting control device of this kind is, for example,
It is shown in the publication No. The configuration shown here includes a motor-driven mechanical timer device that rotates while the electric compressor is in operation (including a delay period), and rotates for a predetermined time to start generating heat from the defrosting heater. I'm doing it like that. That is,
Defrosting is started when the cumulative operating time of the electric compressor reaches a predetermined value.

This is based on the assumption that the amount of frost that grows on coolers such as refrigerators is approximately proportional to the cumulative operating time of the electric compressor throughout the seasons, and that the state of frost is the same throughout the seasons.
Defrosting is always started in a substantially constant frosting state, thereby preventing a decrease in the cooling capacity of the cooler and achieving automatic defrosting.

(c) Problems to be Solved by the Invention However, in reality, the conditions of frost formation on the cooler differ significantly between when the surrounding temperature of the refrigerator is normal and when the temperature around the refrigerator is extremely low, such as in winter. In other words, in an environment where the ambient temperature is relatively high and humidity is high, the internal temperature and humidity of the refrigerator will rise due to the opening and closing of the door, and the operating rate of the electric compressor will be high and the refrigerator will not be operated frequently. Since the frosting speed becomes faster, the total time from the end of defrosting to the start of the next defrosting is also shortened. In addition, because there is a large temperature difference between the cooler and the air passing through the cooler, the moisture in the air freezes as soon as it is sucked in from inside the refrigerator and flows into the cooler, and the crystals become large.
Therefore, frost grows on the air suction side of the cooler, and since the total time is short, relatively low-density, soft frost adheres.

On the other hand, in an environment where the ambient temperature is low, such as in winter, it is difficult for the temperature inside the refrigerator to rise, so the operation rate of the electric compressor becomes low, and the above-mentioned total time becomes longer. In addition, the temperature difference between the cooler and the air passing through the cooler is also relatively small, so even if moisture flows into the cooler and freezes, the crystals are small and do not immediately adhere to the cooler, and the front part of the cooler is not covered. It also grows from the middle tube part to the outflow side K. Moreover, since the above-mentioned total time is long, the time for supercooling the frost is also long, and hard frost with relatively high density will adhere.

On the other hand, to end defrosting of the cooler, a bimetal switch, etc., which operates at a predetermined cooler temperature at which the frost would normally have finished melting, is used. This causes the heater to stop generating heat. This bimetal switch is usually installed on the air intake side of the cooler where frost tends to grow throughout the year, but as mentioned above, the state of frost on the cooler and the position of frost will vary depending on the ambient temperature of the refrigerator. A single bimetallic switch will not provide adequate defrost. In other words, when a bimetal switch is installed on the air intake side of the cooler.

When the ambient temperature is high, frost grows on that part, so the temperature that the bimetal senses is the temperature at which the frost actually ends to melt, but when the ambient temperature is low, most of the frost builds up on the bimetal switch. Since it grows in areas where it is not located and is dense, frost will still remain even if the bimetal switch is activated.

If such a situation is repeated, the amount of remaining hard frost becomes enormous, and air circulation through the cooler becomes impossible, resulting in insufficient cooling within the refrigerator. Therefore, in order to solve this problem, a total of two or more bimetal switches must be installed at the front and rear of the cooler.

B.) Means for Solving the Problems In order to solve the problems, the present invention provides a timer means for accumulating the operating time of the cooling device and generating a defrosting start output at a predetermined accumulated time. 0, a second timer that generates a defrosting start output at predetermined intervals that is sufficiently longer than this integrated time, and a defrosting means that defrosts the cooler with one of the defrosting start outputs. (B) is prepared, and both time-limiting means (B) are initialized by the defrosting start output of this collapse.

(E) Effect According to the present invention, if the ambient temperature of the refrigerator is in a normal state, defrosting is executed by the first timer for a predetermined cumulative operating time of the cooling device, and if the ambient temperature is in a low temperature state and the first When the operating rate of the cooling device falls below the lower limit value of the operating rate of the cooling device determined by the ratio of the predetermined cumulative time of the timer and the predetermined cumulative time of the second timer, the first timer is set by the output of the second timer. It is possible to perform forced defrosting of the trap cooler regardless of the means used, and therefore it is possible to prevent frost remaining after defrosting due to abnormal frost formation at low ambient temperatures.

(F) Embodiment An embodiment will be explained with reference to the drawings. FIG. 3 shows, for example, a cross section of the upper side of this type of refrigerator (1). (2) is τ.

The outer cylinder T31 (41) made of steel plate is a freezer compartment box and a refrigerator compartment box that constitute the freezer compartment (5) and the refrigerator compartment (6), respectively, and are built into the outer box (2) with a gap between them. A heat insulating material (7) is filled inside.Furthermore, a partition wall (8) is formed by the bottom wall of the inner box (3) and the top wall of the inner box (4), and this partition wall (8) and the freezer compartment A cooling chamber (1) is formed between the bottom plate (91 of 051 is the dew pan (1
41 Heater for heating, and draining pan α9
This is a defrost water discharge hose that opens at the front and communicates with the outside of the refrigerator. That is, the frost on the cooler fill, which is melted by the defrosting heater, falls onto the condensation pan and is discharged to the outside of the refrigerator through the discharge hose (161).

The air cooled by the cooler (IIIK) is sucked by a blower (181 (the blower tta is linked to an electric compression engine, which will be described later) installed behind the cooling room αα, and is transferred to the freezing room (5) and the refrigerator room (5) through duct 4. Inside the freezer compartment (5), an electric compressor (to be described later) is stopped by a temperature control device (not shown) to maintain a freezing temperature of, for example, -20°C. are similarly cooled to the refrigeration temperature of, for example, +5°C.The cold air circulating in both chambers +51+6+ is passed through the inlet C2G (2υ
They are sucked in further, merge in front of the cooler aυ, and are sucked into the cooler aυ.

Next, an embodiment of the defrosting control device of the present invention will be described, but since it is constituted by a micro combinator.

First, FIG. 2 shows its functional block diagram. The main part is the electric compressor that makes up the cooling system, and the timer (BL) totals the operating time of this electric compressor.The prisoner is the refrigerator (1) IC.
This is a timer that starts integration after the power is turned on. The timer unit generates a defrosting start output from the output terminal Cl1l after 24 hours of integration, and the timer ■ generates a defrost start output from the output terminal after 8 hours of integration, for example.
Both outputs are input to the OR gate (to), and the defrosting device (b) including the defrosting heater (13) is operated by the output generation.The defrosting device (b) generates the output of the OR gate (to) At that point, the operation of the electric compressor (G) is prohibited and the power supply to the defrosting heater (131 is started. , the defrosting device ends defrosting when this senna detects a predetermined defrosting end temperature, for example +18°C.The output of the OR gate is output from the timer A It is input to the reset terminal (36) C3η of , and resets both timers, thereby restarting the integration from -.

Next, FIG. 1 shows a flowchart of defrosting control of the micro combinator, excluding operation control of an example of an electric compressor. Start from power-on, step (40), the timer counts, step Cυ determines whether the timer's count is 24 hours, and if not, step @2, where the electric compressor ω is running. 1. If the vehicle is running, it is determined whether the timer (Bl counts in step 43 and the timer counts in step (44)) has reached 8 hours.

When the electric compressor ■ is stopped at step (45), or when it is not 8 hours at step (45), step (4
Proceeding to step η, it is determined whether or not the defrosting FLAG is set, and since the FLAG is in the FLAG reset state, the process proceeds to step 6υ where the defrosting motor (131) does not generate heat and returns to the previous step. Repeat the above steps, and when the cooler Uυ is not being defrosted, the timer will continue to integrate from the power on.
B) continues to integrate the operating time of the electric compressor (■), and the inside of the refrigerator is cooled.

When the count reaches 8 hours in step 04, step Ω9
Reset the timer (Al(Bl) at step (461
Set the defrosting FLAG with . Next step (47
), since the FLAG is currently set, proceed to step (4S) to make the defrost heater (131 generate heat and start defrosting the cooler OD.) Next, in step (c), the temperature (TE) of the cooler (Ill) is set. Determine whether the temperature is above +18°C, which is the defrosting end temperature.

If it is lower than +18°C, the process returns to step (4G) and the timer counts.Next, since the timer has been reset in step (c), the count is not 24 hours, so proceed to step (6), but for the electric compressor example Since it is stopped, proceed to step (4). At this time, FLAG is set, so proceed to step (4 seconds), continue to generate heat in the defrosting heater (131, and then proceed to step (491), but the temperature (TE) If the temperature has not risen to +18°C, return to step (4G) again. This is repeated to proceed with defrosting of the cooler Ql.

Also, the timer continues to count during this defrosting process. After that, when the temperature (TE) rises to the defrosting end temperature + 18 degrees Celsius, it advances from step (491) to the step mark to reset FLAG, and in step 6υ, the defrosting heater (131 stops generating heat to end defrosting and step (Return to 40.

When the ambient temperature of the refrigerator (11) becomes lower, the temperature inside the refrigerator becomes difficult to rise, so the operation rate of the electric compressor (■) also decreases. When the timer count becomes low, the timer count becomes 24 hours in step (411), and the timer count goes to step (451).
A) (Reset B1, set FLAG in step (Tsukuda), defrost the cooler ttu as explained above, and end defrosting at the defrosting end temperature +18°C. Therefore, if the ambient temperature As a result, the operating rate of the electric compressor decreases,
24 hours since the last defrost started! When the next defrosting is not started even after %#ff elapses, that is, the cumulative operating time of the electric compressor (7) within 24 hours is less than 8 hours. Operation rate -33
, 3% or less, the cooler αB will be forcibly defrosted regardless of the operating time of the electric compressor (7). Defrosting can be forcibly started before the amount of frost has completely melted by defrosting from K, making it possible to prevent inconveniences due to the occurrence of residual frost. Further, a single sensor may be used to detect the defrosting end temperature at this time, and the number of parts does not increase.

In addition, the low-temperature cold air in the freezer compartment (5) and the relatively high-temperature and high-humidity cold air in the refrigerator compartment (6) are each inlet
Air flows into the cooling chamber (1α) and comes into contact with the front of the cooler aυ, but while the electric compressor (to) and blower are operating, the airflow is fast, so no frost will form on the inner wall of the cooling chamber αO. However, while the electric compressor q and blower - are stopped, the moisture in the cold air from the refrigerator compartment (6) of the cold air flowing into the compartment +51 (61) that naturally flows from the suction port (211) is frozen. It comes in contact with the cold air from the chamber (5), is cooled and condensed, and begins to form frost on the inner wall of the cooling chamber OI in front of the cooler (111).Therefore, the ambient temperature decreases and the electric compressor (7) When the operating rate decreases and the electric compressor (7) and blower are stopped for a long time, there is a risk that frost will accumulate in this area and eventually block the cold air passage. If the temperature in the cooling chamber α1 rises during defrosting of the refrigerator αυ and this frost melts, there will be a problem that melted water will flow back from the suction port (211) and drip into the refrigerator compartment (6). vessel aυ
Conventionally, a special heater was also provided in the front, but according to the present invention, when the operating rate of the electric compressor (7) decreases, the cooler αυ is forcibly removed before the frost builds up in front of the cooler αυ. Since frost is carried out to raise the temperature of the cooling chamber αa, such abnormal frost does not grow, and therefore no special heater or the like is required.

Here, the timer time of timer 03) and the operating rate at the time of forced defrosting determined by them are determined before the amount of frost when the ambient temperature is low increases until it cannot be melted by one defrost. It may be set so that forced defrosting is executed, and is not limited to the embodiments.

(G) Effects of the Invention According to the present invention, when a cooling device such as a refrigerator is in a normal operating state, the operating time of the cooling device is accumulated and defrosting of the cooler is started at a predetermined accumulation. , when the operating rate of the cooling device falls below the lower limit value of the operating rate of the cooling device determined by the first timer and the second timer, that is, when the next defrost is not performed for a predetermined period of time after the previous defrost. can forcefully defrost the cooler regardless of the cumulative operating time of the cooling device. Therefore, when the ambient temperature of the refrigerator is low, the operation rate of the cooler decreases, and even if dense and hard frost grows on the air outlet side of the cooler, the amount will be so large that it will not be able to be completely melted after - times of defrosting. This makes it possible to forcibly remove frost before the frost builds up, which prevents frost from remaining on the cooler and prevents deterioration of the cooling effect due to an increase in residual frost. In addition, a single sensor and the like for terminating defrosting can be used, and no frost remains on the cooler without increasing the number of parts.

[Brief explanation of the drawing]

Each figure shows an embodiment of the present invention. Figure 1 is a 70-chart for explaining the defrosting control device, Figure 2 is a functional block diagram of the same, and Figure 3 is a side sectional view of the upper part of the refrigerator. be. αυ...Cooler, (131...Defrost heater, (
7)...Electric compressor, prisoner (Bl...timer, (
b)...Defrosting device. Applicant Sanyo Electric Co., Ltd. and 1 other agent Patent attorney Masao Sano Figure 1 Figure 21!1

Claims (1)

[Claims] 1. A first timer that integrates the operation time of a cooling device used in a refrigerator or the like and generates a defrosting start output at a predetermined integrated time; and a first timer that starts defrosting at predetermined time intervals that are sufficiently longer than the integrated time. a second timer for generating an output, and a defrosting means for removing frost from the cooler by being operated by one of the defrosting start outputs generated by the two timer means, A defrosting control device that initializes both of the time limit means with a start output.