JPS59185968A - Frost clogging detector - 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 [Field of the Invention] The present invention relates to a freezer or a high-performance refrigerator which has an evaporator and an air circulation device such as a blower in a cooling chamber and cools stored items by circulating cold air. The present invention relates to a device for detecting clogging of an evaporator in a refrigeration system such as a ship.

[Prior art]

In refrigeration equipment such as freezers and refrigerators that are equipped with an evaporator inside the refrigerator and use a method to forcefully circulate the air inside the refrigerator, frost builds up on the evaporator and the cooling stops when the evaporator becomes clogged. Conventionally, defrosting is performed periodically using a timer to prevent the capacity from decreasing. However, since the timer method performs defrosting regardless of the state of fertilization, it is necessary to set the timer time interval according to the conditions in which boxes are most likely to occur in practical use.

Therefore, in the winter when accumulation is less likely to occur, or when the door is opened and closed less frequently, the defrosting operation will be performed after a certain period of time even if there is no debris on the evaporator.
Defrosting power and recooling power were wasted. Therefore, as a countermeasure to this problem, methods of directly detecting frost formation on the evaporator have been proposed. In other words, there is a method in which a light emitting element and a light receiving element are provided in a part of the evaporator, and changes in the transmittance or reflectance of light are used by a display box, and a method in which the surface temperature of the refrigerant circulation vig of the evaporator and the temperature of the air in its vicinity are used. A number of methods have been studied, including one that takes advantage of the fact that the temperature difference between the two changes due to frost formation, and one that uses a vibrator installed in a part of the evaporator to take advantage of the fact that its vibration state changes due to frost formation. I got it. However, although the method of directly detecting each part described above is a useful method for detecting frost buildup on the parts, it is not always possible to detect the degree of clogging of the evaporator that corresponds to a decrease in cooling capacity. There was nothing that could be done about it. In other words, the distribution of frost on the evaporator differs depending on the actual usage conditions of the refrigeration equipment, so although there is frost on the evaporator, there is no clogging that affects the cooling capacity of the evaporator. Even in this case, when a case has occurred where γi@ has not been reached, there is an inconvenience in that it is detected that there is a jam and the removal γi@ crop is performed. This method uses the conventional method described above, or detects the clogging of the evaporator itself, which corresponds to the cooling capacity of the evaporator. There is a reason for this. As a countermeasure to this, it is necessary to increase the number of layer box detectors and arrange them in large numbers in order to detect frost formation in each part of the evaporator. This method becomes extremely complicated in terms of design, increases costs, and is not practical. Therefore, there has been a need for a simple and practical evaporator frost clogging detection device that is not affected by disturbances such as N box distribution, is compatible with cooling capacity, and is simple and practical.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a frost clogging detection device for an evaporator that eliminates the above-mentioned drawbacks of the prior art, is responsive to changes in cooling capacity, and is simple and practical.

[Summary of the invention]

In order to achieve the above object, the present invention provides a refrigeration device such as a freezer or a refrigerator that is equipped with an evaporator and a blower for forced circulation of cold air inside the refrigerator, and is equipped with a cooling device that circulates and exchanges heat inside the refrigerator at a temperature of 2°C. a main air passage passing through the evaporator of 11;
A bypass air path is provided, and a wind speed detection unit installed in a part of the main air path and a part of the bypass air path, a detection signal processing calculation unit, and an output from the detection signal processing logic unit. A box packing characterized in that it is comprised of a comparison section for comparing the calculated signal and a predetermined reference level, and a control section for controlling the defrosting device R by the item (i) from the comparison section. The present invention provides a detection device in which the main air path and the bypass j
Frost clogging of the evaporator is detected based on changes in wind speed on the wind path.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

Figure 1 shows the evaporator and cold air inside the refrigerator. FIG. 1 is a diagram showing the overall structure of a refrigerator-freezer equipped with a 1IIJ circulation mound and a casing clogging detection device according to an embodiment of the present invention. In the figure, 1 is the refrigerator-freezer body, nu is the evaporator, and 3
4 is a blower for forced circulation of cool air, 5 is a refrigerator, and 6 is a cold kite room.

7. 7′ and 7″ are the cooling air flow paths, 8°8
'' and 'B' indicate the air flow path for cooling the storage room. Next, FIG. 2 is a structural diagram when the cooling chamber in which the evaporator 1 is installed is seen through from the back side of the main body 1 on the S-side sake storage shown in FIG. 1. In the figure, 5°C is shown, 9 is a cooling chamber, 1o is a refrigerant pipe that forms a flow path for cooling refrigerant, and 11 and 11' are for improving heat exchange between the refrigerant pipe 1° and air. The fins 12 and 12' are the side plates of the tank which fix the refrigerant pipe 1o and form the evaporator name, and also form the main air passage for the air that undergoes heat exchange through the evaporator pipe. Side plate 1
2 and 12' project from the tips of the fins 11 and 11' on the windward side of the air in the refrigerator or (and) on the lower elevation 1 of A. Reference numeral 16 designates a gas inlet from the cold storage chamber 9 shown in FIG. 15 is refrigerator compartment 6
This is the main air path for the return air from the freezer compartment 5 to pass through the evaporator 2, where it is heat exchanged, re-discharged. It consists of one fox area. Reference numerals 16 and 16' designate bypass air passages on the outside of the side plates 12' and 26 and 12'. 17 and 1
Reference numeral 7' indicates a wind speed detection unit provided in the main air passage 15, and 18 and 18' indicate wind speed detection units provided in the bypass air passage portions 16 and 16'.

Next, the method for detecting sheath clogging in this embodiment will be explained. In FIG. 2, when there is no frost on the evaporator 2, the wind speed in the main air passage 15 between the side plates 12.1'2' of the evaporator l is high, and the bypass air passage section 16 and The wind speed at 16' is small. However, the air return port 16 from the refrigerator compartment 6
The air that enters from the air return ports 14 and 14' from the cold IN room 5 causes frosting on the evaporator to progress.
When the box becomes clogged, the evaporator 7's plate 12,
12', the wind speed in the main air passage 15 becomes small, and conversely, the air returns to the bypass air passage parts 16 and 16', and the wind speed in the bypass air passage parts 16 and 16' increases.

As the operating time of the refrigerator-freezer continues and the evaporator becomes clogged, the wind speed in the main air passage 15 of the evaporator further decreases. On the other hand, the bypass air passage sections 16 and 16'
The wind speed at
On the contrary, the wind speed in the bypass air passage section decreases. In other words, the wind speed in the main air passage 15 of the evaporator (E) decreases as the number of boxes to the evaporator (E) progresses until one box is clogged, but the wind speed in the bypass air passages 16 and 16' decreases. It was found that as frost builds up on the evaporator l and as the boxes become clogged, the thickness increases and then decreases. FIG. 3 is a diagram showing the results of wind speed detection by the wind speed detecting section 17 provided in the main air path 15 of the evaporator E and the wind speed detecting section 18 provided in the bypass air path section 16. In the figure, a curve 19 represents the wind speed transition of the wind speed detection section 17, a curve 20 represents the wind speed transition of the wind speed detection section 18,
Curves 21 indicate the changes in the wind speed difference between the main air passage 15 and the bypass air passage section 16, respectively.

Next, a box jam detection device in this embodiment will be explained. Figure 4 shows its configuration. In the figure, 22 is a wind speed detection unit installed in the main air path and bypass air path of the evaporator, 26 is a processing calculation unit that processes and calculates the detection signal from the wind speed detection unit 22, and 24 is a signal from the processing calculation unit 23. , and a comparison section for comparing with the standard level set in advance,
Reference numeral 25 denotes a control section for controlling a self-exclusion device (not shown) based on the signal from the comparison section 24.

The operation of the box jam detection device will be described below. If a thermistor element that is self-heated to a temperature higher than the surrounding temperature is used as the wind speed detection unit installed in the main air path and bypass air path of the evaporator, if there is no N box in the evaporator path, the main air Since the wind speed in the bypass air passage is higher than that in the bypass air passage, the thermistor element on the main passage side has better heat dissipation than the thermistor element on the bypass air passage side, and the heat generation temperature is lower. Since the resistance increases, the voltage applied from the element side to the processing calculation section side increases. The voltage applied from the thermistor element side provided in the main air path of the evaporator is defined as the voltage applied from the thermistor element side provided in the bypass air path section, and the voltage rm and VB are sent to the processing calculation section 23. , the processing calculation unit 23 calculates, for example, ``voltage difference (VBFm)''.
is determined, and this voltage difference is sent to the comparison section 24. .

The comparator 24 compares this voltage difference with the reference value C, but when there is no frost, this voltage difference is negative, and (VE-V
,, ) < O < C, the comparison unit 24 does not send a signal to the control unit 25 for controlling the defrosting device, and defrosting is not performed. Then, when the amount of N frost on the evaporator increases, the main air path of the evaporator becomes clogged, and return air from the freezer and refrigerator compartments begins to circulate into the bypass air path. When the wind speed is higher than the wind speed in the main air path, the voltage difference (Vs-V;
After n) turns positive, it further increases, and when it reaches a predetermined reference value CK, the comparator 24 sends a signal (g) to the controller 25, and the controller 25 operates a defrosting device such as a defrosting heater. It is possible to defrost the evaporator and prevent a decrease in cooling capacity due to frost clogging.In this embodiment, an example of the installation location of the wind speed detection section has been described, but the installation location can be
Similar results can be obtained in the main air path of the evaporator and in the bypass air path outside the side plate of the evaporator (for example, 17' and 18' in FIG. 2).

According to this embodiment, in order to detect clogging of the evaporator, the side plate of the evaporator is placed on the leeward side of the air inside the refrigerator.
Or (and) in the leeward direction, the fins are configured to protrude from the tips of the fins for improving heat exchange between the refrigerant pipe and the air, thereby forming a main air path and a bypass air path.

It has the advantage of being able to detect frost clogging in a simple and practical manner.

In addition, in this embodiment, the evaporator has a structure in which each refrigerant pipe has an independent fin to prevent heat exchange between the refrigerant pipe and the air.

In the case of an evaporator in which the fins have a continuous integral structure from the upwind fin to the leeward fin, the two outermost fins of the fin can be replaced by another fin instead of the first rule plate. A similar effect was obtained even if the main air path section and the bypass air path section were configured by making the fins protrude from the tips. Furthermore, a guide plate for the air passage having the same function as the side plate shown in this embodiment may be installed on the outside of the evaporator, on the windward side or on the leeward side so as to protrude from the tip of the fin. It goes without saying that the same effect as above can be obtained even if the air passage is formed by

〔Effect of the invention〕

According to the present invention, in a cooling device for a freezer, a refrigerator, etc., which is equipped with an evaporator and a blower for forced cold air circulation inside the refrigerator, a main air path passing through the evaporator for circulating the air inside the refrigerator and exchanging heat. , a bypass air path passing through the evaporator is provided;
A wind speed detection unit is installed in each, and clogging of the evaporator is detected using the difference in wind speed between the bypass air path and the main air path, so frost clogging of the evaporator forming the main air path can be detected directly. It can be detected easily and is not affected by external disturbances such as frost distribution, has corresponding cooling capacity, and is simple and practical.
A frost clogging detection device that can save power can be provided.

[Brief explanation of drawings]

FIG. 1 is a side cross-sectional view showing the overall structure of a refrigerator-freezer equipped with an embodiment of the box jam detection device according to the present invention, FIG. 2 is a structural diagram of the cooling chamber of the refrigerator-freezer seen from the back, and FIG.
The figure is a characteristic diagram showing the wind speed characteristics in the wind speed detecting section of the embodiment, and FIG. 4 is a block diagram showing the configuration of the embodiment. . Explanation of codes...Evaporator 3...Cold air forced circulation blower? ...Cooling chamber 10...Refrigerant pipe 1111'
...Fin 12, 12'...Side plate 15...
Main air passage 16.16'... Bypass air passage section 17.17', 18, 18'... Wind speed detection section 22
...Wind speed detection section 23...Processing calculation section 24...
・Comparison section 25...Famine control section 1 agent lawyer
Nao Tachibana 1 Husband Liu Z Figure 3F1 Amount of frost formation

Claims (1)

[Claims] (1) A device for detecting frost clogging of an evaporator in a refrigeration device such as a freezer or a refrigerator that is equipped with an evaporator and a blower for forced circulation of cold air in the refrigerator, the air path through which cold air is circulated by the blower. In part, there are two air passages: an earthenware pot that passes through an evaporator for heat exchange of circulating air, and a bypass air passage that does not pass through the evaporator, and the main air passage and the bypass air passage are provided with two air passages. A detection signal processing calculation unit which is equipped with a wind speed detection unit and inputs the signals from the wind speed detection unit, respectively, and a detection signal processing calculation unit which inputs the signals from the wind speed detection unit, and a detection signal processing calculation unit that compares each calculation from the inspection target processing calculation unit with a predetermined reference level. A comparison unit, and a control unit for controlling the husk removing device based on the signal from the comparison unit? A frost clogging detection device comprising: (2. The frost clogging detection device according to claim 1, characterized in that the wind speed detection section is composed of a self-heating thermistor element. In the box clogging detection device according to claim 1, the main air passage and the bypass air passage have a side plate constituting an evaporator for circulating indoor air and exchanging heat, or a function equivalent thereto. "or (and) A clogging detection device characterized by protruding from the tip of a heat exchanger fin on the leeward side.