JPS6144239A - Device for detecting clogging of air suction filter - Google Patents

Abstract

PURPOSE:To prevent any erroreous operation of the titled device due to variations of the temperature of external air by detecting the temperature of air in a heat exchanger or air after passing a heat exchanger and the temperature of air before passing the heat exchanger, and discriminating clogging of the filter when the difference between both temperatures is higher than a predetermined value. CONSTITUTION:Air which has been cooled by an evaporator in a coolant cycle, is blown off through a duct 56. In this case, in a state where a filter 1a is not clogged, the difference between the temperature of air for cooling a condenser 2 immediately after passing the filter 1a and that on the surface of the condenser 2 is 8-10 deg.C. However, at an extraordinary time when the filter 1a was clogged, the amount of cooling air decreases. Hence, the temperature difference increases extraordinarily to 15 deg.C. This value is converted into a voltage by a detector 5. If the value of a resistor 20 is set so as to generate a voltage corresponding to the above described temperature difference of 15 deg.C, a comparator 11 generates an output signal ''1'' through an output terminal 11c. Consequently, a coil 12a of a relay 12 is supplied with power and is excited to close a contact 12b and light an alarm lamp 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a clogging detection device for a filter provided at an air intake port of a case containing a heat exchanger of a refrigeration cycle.

[Conventional technology]

Conventionally, there have been known air-conditioning systems that cool the surrounding air when refrigerant compressed in a refrigeration cycle is liquefied in a condenser and evaporated in an evaporator. An air filter is attached to the intake port of the cooling air to be cooled. This air filter removes fine particles and dust from the intake air, but if you use the air conditioner for a long time, these particles will clog and prevent a sufficient amount of air from passing through. As a result, the cooling effect decreases.

Therefore, conventionally, a device has been devised that activates an alarm device by utilizing the fact that the difference in air pressure between the inlet side and the outlet side of the filter increases when the filter becomes clogged.

[Problem that the invention seeks to solve]

However, the conventional clogging alarm device described above requires an actuator such as a diaphragm or a heros in order to detect the pressure difference between the inlet side and the outlet side of the filter, and an operating space for these actuators is required. Another problem is that the structure becomes complicated because the operation of the actuator is converted into an electrical signal.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a clogging detection device for an air intake filter of a refrigeration cycle, which has a simple structure and requires less space for installation.

[Means for solving problems]

Therefore, in order to achieve the above-mentioned technical problem, the air intake filter clogging detection device of the present invention includes a case having an air intake port and an air outlet, and an air between the air intake port and the air outlet in the case. a heat exchanger for a refrigeration cycle provided in the passage; a blower provided in the case for sucking air into the case from the inlet; a dustproof filter provided in the inlet; a detector that detects the temperature of the air after passing through the filter and before passing through the heat exchanger (first temperature), and the temperature of the air after passing through the heat exchanger or the exchanger (second temperature); a comparison means for comparing a first temperature and a second temperature detected by the device; and an alarm means that is activated when the comparison means determines that the difference between the first temperature and the second temperature is larger than a set value. It consists of

〔Example〕

The present invention will be explained in detail below based on embodiments shown in the drawings.

FIG. 1 shows a cooling device that cools a relatively large room such as a factory. Inside a case 50, as shown in FIG. , a capillary tube 52 serving as a pressure reducing means, an evaporator 2, and an accumulator 53 are housed, and these are sequentially connected by a refrigerant pipe 54.

As the refrigeration cycle circulates, the cooling air sucked into the cooling air intake port 55 is cooled by the evaporator 4, and then turned into cold air and sent out from the duct 56 to the area to be cooled. It has become.

On the other hand, as is well known, the condenser 2 is air-cooled in order to efficiently condense the high-temperature, high-pressure refrigerant gas compressed by the compressor 51 into liquid refrigerant. In FIGS. 1 and 2, reference numeral 1 is an air inlet for cooling the condenser, and a blower 3 is used to connect the air inlet 1 to the case 5.
After cooling the condenser, the air sucked into the inside of the case is discharged to the outside of the case from an exhaust port 57 at the top of the case. Arrow A in FIG. 2 indicates the direction of intake of cooling air.

A dustproof filter 1a is attached to the air inlet 55 for cooling and the inlet 1 for cooling the condenser. The filter 1a is made of a wire mesh and polypropylene or the like provided inside the wire mesh to remove fine dust from the intake air.

Figure ff13 shows the state in which the temperature sensor 5 of the present invention is installed. As can be seen from this Figure 3, the temperature sensor 5
is provided in the upper part of the condenser 2 in contact with the surface of the refrigerant tube 2a, and the surface temperature (second temperature) of the condenser 2 and the condenser 2
It is configured to detect the air temperature (first temperature) before adding the upper condenser 2. That is, in the first embodiment, the present invention is applied to detect clogging of the filter 1a provided at the air intake port 1 for cooling the condenser 2.

The specific structure of the detector 5 will be described below. Fourth
The figure shows its specific structure, and the detector 5 is composed of a thermoelectric element that utilizes the Seebeck effect.

That is, in FIG. 4, a P-type semiconductor 6 made of 3i2 doped with Mn and Fe 3 i 2 doped with CO are used.
An n-type semiconductor 7 made of the above is bonded at a P-n junction 8, and an electrode plate 9 for detecting the generated electromotive force is bonded to the other end. In addition, a p-type semiconductor 6 and an n-type semiconductor 7
A cooling fin 10 made of aluminum or the like is bonded to the end opposite to the Pn junction so as to contact the front electrode plate 9 .

The P-n junction 8 is fixed in contact with the surface of the condenser 2, and the other end to which the radiation fins 10 are connected is attached to the filter 1.
It is arranged in the flow path of the cooling air that has passed through a.

FIG. 5 shows an electric circuit for operating an alarm by comparing the detected temperatures of the detectors in this embodiment.

In FIG. 5, one lead wire 9a of the detector 5 is grounded, and the other lead wire 9b is connected to the input terminal 11a of the comparator 11. Also, another input terminal 11 of the comparator 11
b is a resistor 20 to which a potential corresponding to the set temperature difference is set.
is connected, and the comparator 11 is connected to the input terminal 11
It is configured to generate an output signal of "1" from the output terminal 11C when the potential of the input terminal 11b is higher than the potential of the input terminal 11b. The output terminal 11c of this comparator is connected to a relay coil 12a of a normally open contact type relay, one end of the relay contact 12b is connected to a power source 30, and the other end is connected to an alarm lamp 13 serving as an alarm means.

FIG. 6 shows the operation panel 31 provided in the case 50,
The operation panel 31 includes an operation switch 32 for starting and stopping the cooling device, a power lamp 33 that lights up when the operation switch 32 is switched to the air blowing or cooling mode position, and a power lamp 33 for controlling condensation generated in the evaporator 4 of the cooling device. If the water stays above a certain amount, the air conditioner will automatically stop and the abnormality lamp 3 will turn on.
4 and the alarm lamp 13 of this embodiment are provided.

Next, the operation of this embodiment having the above configuration will be explained.

First, when the operation switch 32 is switched to the cooling mode, the compressor 51 starts supplying cooling air (not shown)! Ita and the blower 3 for cooling the condenser operate to circulate the refrigerant cycle, and the air cooled by the evaporator 4 is blown out through the duct 56. Here, when the filter 1a is not clogged, the temperature difference between the cooling air of the condenser 2 immediately after passing through the filter 1a and the surface of the condenser 2 is 8 to 10°C.
However, in an abnormal situation where the filter 1a is clogged, the amount of cooling air decreases, so the temperature difference increases abnormally by 15°C.

Therefore, when the temperature difference exceeds 5°C, the detector 5
The temperature difference between the P-n junction 8 and the radiation fin 10 also exceeds 15° C., and a voltage proportional to this is generated due to the Seebeck effect. Therefore, at this time, if the set value of the resistor 20 is set to generate a voltage corresponding to the temperature difference of 15.degree. C., the comparator 11 generates an output signal "1" from the output terminal 11C. Therefore, the coil 12a of the relay 12
is energized and excited, closes contact 12b, and alarm lamp 1
3 lights up.

Next, other embodiments of the present invention will be described.

(1) (Second Embodiment) The thermoelectric element 5 is used as the power source for the indicator light 13.
It is also possible to use the electromotive force of As shown in FIG. 7, if the reference potential (normal temperature difference) becomes abnormal, a current flows through the Zener diode 14 and lights up the indicator lamp. The thermoelectric element 5 will serve as both a sensor and an actuator. If the indicator light does not gradually become brighter, the 8th
The relay may be omitted as shown in the figure.

(2) (Third Embodiment) The method for detecting the temperature of the cooling air on the surface of the capacitor 2 is not limited to the thermoelectric element.

For example, NTC thermistors 15 and 16 whose main component is a transition metal oxide such as Ni-Co-Mn are placed on the surface of the condenser 2 and in the cooling air flow path, respectively, as shown in FIG. The temperature difference is detected from the value using the circuit shown in Figure 10 and an abnormality is displayed. That is, in FIG. 10, the power supply voltage is input to the input terminal 11a of the comparator 11,
A voltage divided by thermistors 15 and 16 is input to the input terminal 11b. The other configurations are similar to the electric circuit shown in FIG.

In this example, when the difference between the surface temperature of the condenser 2 and the cooling air temperature becomes large, the potential at point e in the hand box 10 becomes smaller compared to the normal state, and the comparator outputs "1" from the output terminal 11C.
A signal is output and the alarm lamp 13 is turned on in the same manner as in the above embodiment.

Furthermore, the means for detecting temperature is not limited to a thermistor or thermoelectric element, but may be replaced with a thermocouple or other device that can detect the vicinity of the operating temperature.The material of the thermoelectric element is not limited to 3e3i2, for example, Bi2Te3゜MnSi2 ．． A material having a Peltier effect such as CoSi or a combination thereof may also be used.

Further, the means for detecting temperature is not limited to a thermistor or a thermoelectric element, but may be replaced with a thermocouple or other means capable of detecting the vicinity of the operating temperature. The material of the thermoelectric element is not limited to FeSi2, for example, B i 2 T e 3, MnSi2,
A material having a Peltier effect such as CoSi or a combination thereof may also be used.

Further, in the above embodiment, the surface temperature of the condenser 2 is detected as the first temperature, but in addition to this, for example, the temperature of the heated air after passing through the condenser may be detected.

Further, the heat exchanger of the refrigeration cycle is not limited to the condenser 2, but can be similarly applied to the evaporator 4, and is also effective as a device for preventing clogging of a filter provided at the air intake port 55 of the evaporator 4. Needless to say.

〔Effect of the invention〕

As described above, according to the present invention, when detecting clogging of the dust filter provided at the air intake port to the heat exchanger of the refrigeration cycle, the temperature of the heat exchanger or the air after passing through the heat exchanger is detected. Since the system detects the temperature of the air at the exit part of the heat exchanger and the air temperature at the exit part of the heat exchanger, and determines that the filter is clogged when the temperature difference between the two is higher than a certain value, it requires less mechanical actuators than before. It requires less installation space and is easy to install. Moreover, it does not simply detect the temperature of the heat exchanger, but also uses the relative temperature difference with the air that has passed through the filter, so it can operate without malfunction even when the outside temperature fluctuates, and the product This has the effect of increasing the reliability of

[Brief explanation of drawings]

The drawings all show embodiments of the present invention; FIG. 1 is a plan view of the cooling device of the first embodiment, FIG. 2 is a plan view showing a schematic internal configuration of FIG. 1, and FIG. Enlarged perspective view of the main part, No. 4
The figure is an enlarged plan view of the main part of Figure 3, Figure 5 is an electric circuit diagram of the first embodiment, Figure 6 is a plane view of the operation panel of the air conditioner, and Figures 7 and 8 are the second embodiment. FIG. 9 is a schematic configuration diagram of the third embodiment, and FIG. 10 is an electrical circuit diagram of the third embodiment. 50... Case, 55... Cooling air intake port, 56
... Outlet tally, 57... Outlet for air that cools the condenser, 1... Inlet for air for cooling the condenser, 1a...
- Filter, 2... Condenser, 3... Condenser cooling blower, 4... Evaporator, 52... Capillary tube, 51... Compressor, 53... Accumulator, 5
Detector, 6 P-type semiconductor, 7 N-type semiconductor, 10 Cooling fin, 11 Comparator,
13... Alarm lamp, 14... Zener diode, 15.16... Thermistor.

Claims (1)

[Claims] A case having an air inlet and an air outlet, a refrigeration cycle heat exchanger provided in an air passage between the air inlet and the air outlet in the case, and a refrigeration cycle heat exchanger provided in the case. a blower that sucks air into the case from the suction port; a dustproof filter provided at the suction port; and a temperature of the air after passing through the filter and before passing through the heat exchanger (a first temperature). ), and a detector for detecting the temperature of the air after passing through the heat exchanger or the exchanger (second temperature); and a comparison means for comparing the first temperature and second temperature detected by the detector; A clogging detection device for an air intake filter, characterized in that the comparison means includes an alarm means that is activated when the comparison means determines that the difference between the first temperature and the second temperature is larger than a set value.