JPS62782A - Method of detecting clogging of air filter for condenser - 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 Industrial Application) The present invention relates to a method for detecting clogging of an air filter of a condenser in a refrigeration cycle of a refrigeration or refrigerated showcase.

(Prior art) As a conventional detection method of this kind, for example, Japanese Patent Application Laid-Open No. 57-9
As shown in Publication No. 0562, the inflow air temperature (tl) to the air filter of the condenser and the condensation temperature (tC)' of the condenser are measured, and these temperature measurements are calculated based on whether dust or the like is present in the air filter. When a predetermined correlation is reached between the ratio (Q') of the amount of air passing through the condenser when no dust is attached to the amount of air passing through the condenser when dust etc. is attached to the air filter, A method is known in which a detection signal is issued to indicate that clogging has occurred to the extent that cleaning is required, and an alarm display device is activated in response to the detection signal. Although this four-alarm detection method properly displays an alarm under normal conditions, it has the following drawbacks.

(Problems to be Solved by the Invention) In the conventional detection method, when an abnormal condition such as a blower failure, an abnormal rise in outside temperature, or poor heat exhaust occurs, the air filter is less likely to be clogged. Even when there is no need for cleaning, the condensing temperature rises and the measured temperature values have a predetermined correlation, resulting in a malfunction in which a detection signal indicating the occurrence of a clog that requires cleaning is generated.

The purpose of the present invention is to solve all the problems of the prior art described above, and therefore, to provide a method for detecting clogging of a condenser air filter in a refrigeration cycle, which prevents malfunction even under abnormal conditions. It is to provide.

(Means for solving the problem) In the detection method according to the present invention, the temperature of the condenser and the temperature of the air flowing into the air filter or the temperature of the air flowing out from the condenser are measured, and the correlation between these temperature measurements is established. This method is similar to the conventional method in that it detects clogging of the air filter, but this method also calculates the ratio of the amount of air passing when the air filter is not clogged to the amount of air passing when the air filter is likely to be clogged. Based on a preset relationship regarding the time until clogging, a detection signal indicating that clogging has occurred is not emitted until the time corresponding to the clogging that requires cleaning has elapsed.

(Operation of the means for solving the problem) Therefore, in the detection method according to the present invention, a detection signal indicating that the clogging has occurred is generated based on the correlation between the condensation temperature and the temperature of the air flowing into the air filter. However, the detection signal will not be emitted until the time corresponding to the clogging has elapsed, which prevents malfunctions in which a detection signal indicating clogging occurs even though no clogging has actually occurred. Ru.

(Embodiments) Next, embodiments of the present invention will be described with reference to the drawings and references. 1 to 5 show an example of an apparatus for implementing the present invention, in which (1) is a compressor, (2) is a compressor, and (2) is a compressor.
is a condenser, (3) is a throttle mechanism, and (4) is an evaporator.
These are sequentially connected via piping to form a refrigeration cycle. A blower (5) is attached to the condenser (2) to provide forced ventilation. In addition, an air filter (6) made of wire mesh or other material is installed around the air inlet of condenser (2) D, so that dust and dust in the atmosphere are removed from the condenser (2). It completely prevents it from entering.

The present invention detects clogging of the air filter, and therefore, in the illustrated embodiment, the air filter (6
) is equipped with a detector (7) for measuring the temperature of the incoming air, and a detector (8) for measuring the condensation temperature is provided on the condenser (2).
will be installed. (9) is a detection circuit that inputs and processes signals from the detectors (7) and (8);
Is it the processing result of the detection circuit? Enter and thereby buzzer or lamp az etc? This is a working alarm display device. In the circuit implementing the present invention, an alarm display determination circuit (11) is further installed between the detection circuit (9) and the alarm display device (10).

In this detection method, the air filter (6) is covered with dust, etc., and the condenser is (
2) In relation to the ratio of passing air volume (t/), the detector (7)
The relationship between the temperature measurement value (ti) and the condensation temperature (tc) measured by the detector (8) is determined in advance. Figure 4 shows a complete graph showing such relationships, and in this graph, at '/=0.5, approximately 90% of the surface area of the air filter (6) is blocked by dust. . An air filter clogging detection algorithm is formed based on the relationship between temperature ti and tC regarding the value of d. Furthermore, in the present invention, the relationship between the passing air volume ratio (C) and the clogging time (T) until the ratio ('/') is reached is determined in advance,
The relationship is used as a total control algorithm. FIG. 5 is a 9-T graph illustrating this relationship. In FIG. 5, the solid line shows the relationship under the worst ambient conditions with a lot of dust, and the broken line shows the relationship under good ambient conditions with little dust.

If the refrigeration cycle is operated when the air filter needs to be cleaned when 'r = 0.5, that is, when the alarm is displayed, the incoming air will be expressed as a point on the curve of 'r = 0.5 in Figure 4. When the relationship between the temperature ti and the condensing temperature tc is established, that is, when they become tie and tcl, respectively, the detection circuit (9) issues a detection signal indicating that the determination circuit (111) is clogged. When the 70 signal is manually input to the judgment circuit (111), the clogging time of '/=0.5 and the operation time of the refrigeration cycle are compared from the relationship of 9 and T as shown in Figure 5, and the operation time is determined. If the time is T6 or more in FIG. If the operating time does not exceed the clogging time T3i, the judgment circuit will not send a signal to the alarm display section, and therefore the lamp (12) will not be lit.

Note that in the above embodiment, the temperature of the air flowing into the condenser is used, but the temperature of the air flowing out from the condenser (2) may be used instead of that temperature, and in that case, the temperature of the air flowing into the condenser (2) can also be used. Similarly, all clogging of the air filter (6) can be detected.

(Effects of the Invention) As described above, according to the present invention, a control algorithm based on the relationship between the passing air volume ratio of the presence or absence of dust on the air filter and the estimated time of entering the air filter is added as a determining element, so that abnormality can be detected. There is no malfunction that causes clogging to be detected and displayed when no clogging occurs under the conditions, and clogging can always be detected accurately.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a refrigeration cycle including equipment for carrying out the entire method of the present invention, Fig. 2 is a perspective view of a condenser during the cycle, Fig. 6 is a front view of an alarm display member, and Fig. 4 is an eye view. FIG. 5 is a diagram showing the relationship between clogging and temperature, and FIG. 5 is a diagram showing the relationship between clogging and time.

Claims (2)

[Claims] (1), measuring the temperature of a forced draft condenser in a refrigeration cycle and the temperature of air flowing into an air filter provided in the condenser or the temperature of air flowing out from the condenser;
In the method of detecting that the air filter is clogged requiring cleaning based on the correlation between these temperature measurements, the method further includes detecting clogging relative to a preset amount of air passing when the air filter is not clogged. Based on the relationship between the ratio of the passing air volume when the clogging occurs and the time until the clogging occurs, a detection signal indicating that the clogging has occurred is not emitted until the time corresponding to the clogging that requires cleaning has elapsed. Features a clogging detection method for condenser air filters. (2) A warning is issued based on a detection signal indicating that a clogging has occurred based on a correlation between the temperature measurement values after a time period corresponding to the clogging that requires cleaning has elapsed. Detection method according to scope 1.