JPH03177762A - Detector for amount of refrigerant packed in freezing cycle - Google Patents

Abstract

PURPOSE:To numerically display distinctly the actual amount of a refrigerant packed, without being affected by an external heat factor, by specifying the amount of the refrigerant packed at a point of time when the degree of supercooling of the refrigerant on the outlet side of a condenser, which is found based on the discharge pressure of a low-pressure shell type compressor and a refrigerant temperature on the outlet side of the condenser, reaches the level of about 1 deg.C, as an optimum value. CONSTITUTION:After a refrigerant is packed from a refrigerant packing port 12, the discharge pressure Pd of a low-pressure shell type compressor 1 is detected by a pressure sensor 10, and a refrigerant temperature T on the outlet side of a condenser 2, by a temperature sensor 15. Subsequently, a microcomputer 11 computes the degree of supercooling SC of the refrigerant on the basis of the discharge pressure Pd and the refrigerant temperature T. In the case where the degree of supercooling SC of the refrigerant does not reach the level of 1 deg.C owing to a shortage of the refrigerant in a freezing cycle, DELTAMkg of the refrigerant is packed, and, when the degree of supercooling SC reaches the level of 1 deg.C, the total amount SIGMAM of the refrigerant packed at a point of that time is specified as the optimum amount of the refrigerant to be stored in a storage means. The rate C of the refrigerant packed is then computed by applying the formula of C=(SIGMAM+kDELTAM)/SIGMAM on the basis of the total amount SIGMAM of the refrigerant packed at the aount k M of the refrigerant additionally packed thereafter. The computed value of the rate C of the refrigerant packed is thus displayed on a display unit 13 in terms of a numeric value.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a device for detecting the amount of refrigerant filled into a refrigeration cycle when installing a vapor compression refrigeration cycle applied machine such as a refrigerator or an air conditioner. In particular, the present invention relates to a refrigerant charge amount detection device for a refrigeration cycle that includes means for displaying the refrigerant charge amount as a ratio based on an appropriate value.

[Prior Art] As conventional refrigerant filling amount detection devices for this type of refrigeration cycle, there is a first conventional example disclosed in Japanese Patent Application Laid-Open No. 1-107070, and a first conventional example disclosed in Japanese Patent Application Laid-Open No. 158966-1989. A second conventional technique can be mentioned.

FIG. 4 shows an indoor unit of an air conditioner equipped with a refrigerant charge amount detection device for the refrigeration cycle of the first conventional example, and FIG.
) is a front view, and FIG. 4(b) is a side view.

In the figure, (24) is the air inlet of the air conditioner, (2
5) is an air outlet, (26) is a heat exchanger that functions as an evaporator during cooling operation and as a condenser during heating operation, (27) is a liquid refrigerant collection pipe, and (28) is a gas refrigerant collection pipe. be. (29) is the thermistor A installed in the liquid refrigerant collecting pipe (27), and (30) is the gas refrigerant collecting pipe (2).
8) is a thermistor B, and (31) is a thermistor C installed near the air suction port (24).

(32) is a control device, (33) is a compressor that adiabatically compresses the refrigerant, and (34) is a blower.

The operation of the refrigerant charge amount detection device for the refrigeration cycle of the first conventional example having the above configuration will be described.

The temperature of each part of the heat exchanger (26) is determined by thermistor A (29).
, thermistor B (30), and thermistor C (3
1). Then, the control device (32) detects a refrigerant shortage in the refrigeration cycle when at least one of the following temperature conditions is satisfied.

■ The temperature difference between the evaporator inlet refrigerant and the evaporator outlet refrigerant is greater than a certain value.

■ The temperature difference between the evaporator outlet refrigerant and the evaporator intake air is smaller than a certain value.

■ The temperature difference between the condenser inlet refrigerant and the condenser outlet refrigerant is greater than a certain value.

■ The temperature difference between the condenser outlet refrigerant and the condenser suction air is smaller than a certain value.

■ The temperature difference between the evaporator intake air and the evaporator outlet air is smaller than a certain value.

■ The temperature difference between the condenser intake air and the condenser outlet air is smaller than a certain value.

Therefore, by generating an alarm signal or stopping the operation of the air conditioner when a refrigerant shortage is detected, it is possible to prevent a burnout accident of the compressor.

FIG. 5 is a block diagram schematically showing a second conventional refrigerant charge amount detection device for a refrigeration cycle.

In the figure, (41) is the compressor of the air conditioner, (42)
is an outdoor heat exchanger, (43) is an indoor heat exchanger, (44) is a pressure reducing device, and (45) is a four-way valve. (46a) is a temperature detector attached to the middle part of the entrance and exit of the outdoor heat exchanger (42), and (46b) is a temperature detector attached to the outlet side of the outdoor heat exchanger (42). (47a) is a temperature detector attached to the middle part of the entrance and exit of the indoor heat exchanger (43), and (47b) is a concentration detector attached to the outlet side of the indoor heat exchanger (43). (48) is a control device, and on its input side, each of the temperature detectors (46a),
(46b), (47a), and (47b) are connected, and a display (49) is connected to the output side. (51) is a blower.

The operation of the refrigerant charge amount detection device of the second conventional refrigeration cycle in the above configuration is taxed.

When a certain amount of refrigerant is sealed in the refrigeration cycle and the air conditioner is operated for cooling, the outdoor heat exchanger (42) functions as a condenser, and the temperature of the refrigerant in the middle of the condenser is detected by the temperature detector (42).
6a), and the refrigerant temperature on the outlet side of the condenser is detected by a temperature detector (46b). The control device (48) each temperature detector (46a), (46
Calculate the degree of subcooling of the refrigerant based on the signal from b).

Since this degree of supercooling has a substantially constant relationship with the amount of refrigerant charged in the refrigeration cycle, the control device (48) determines whether the amount of refrigerant charged is excessive or insufficient based on the degree of supercooling, and displays the determination result on the display (48). (1) is displayed by flashing light emitting diodes. Therefore, it is possible to easily check visually whether the amount of refrigerant is too much or too little. Note that during heating operation of the air conditioner, the indoor heat exchanger (43) functions as a condenser.

[Problem to be Solved by the Invention] However, according to the first conventional refrigerant cycle refrigerant filling amount detection device, as described above, the refrigerant temperature difference at the entrance and exit of the heat exchanger (26) or the air temperature difference Alternatively, since the amount of refrigerant enclosed is detected based on the temperature difference between the refrigerant and air, at least three temperature detection means, that is, thermistor A (2), thermistor B (30), and
Thermistor C (31) was required, and the configuration and signal processing were complicated. In addition, each temperature detection means is connected to a heat exchanger (2
6), so the heat exchanger (26)
In the event that the air blower (34) becomes clogged or the blower (34) malfunctions, the detected value may become inaccurate due to the external thermal influence, and there is a possibility that an appropriate amount of refrigerant cannot be detected. Furthermore, the control device (32) has a function of generating an alarm signal or an operation stop signal when detecting a refrigerant shortage, but it also has a function of displaying the actual amount of refrigerant shortage in relation to the appropriate amount of filling. Because it was not equipped, work efficiency was poor when filling refrigerant when installing an air conditioner.

On the other hand, in the case of the second conventional refrigerant filling amount detection device for the refrigeration cycle, the temperature detectors (46a) and (47a) are installed in the intermediate portions of the outdoor heat exchanger (42) and the indoor heat exchanger (43), respectively. each heat exchanger (42),
(43) becomes clogged or the blower (51) malfunctions, the detection accuracy will decrease due to external thermal factors, thereby making the calculated value of the degree of supercooling inaccurate.
There was a possibility that the amount of refrigerant charged could be incorrectly determined.

Moreover, although the display device (49) has a function of displaying the excess or deficiency of refrigerant by flashing light emitting diodes, it cannot numerically display the actual amount of excess or deficiency of refrigerant in relation to the proper amount of filling. When installing an air conditioner, etc., it was not possible to proceed with the filling work while accurately grasping the amount of refrigerant to be filled.

Therefore, an object of the present invention is to be able to easily configure a detection mechanism for the amount of encapsulation, to be able to accurately detect the appropriate amount of encapsulation without being affected by external heat factors, and to be able to accurately detect the amount of encapsulation in a ratio to the appropriate value. It is an object of the present invention to provide a refrigerant charge amount detection device for a refrigeration cycle that can clearly display the amount of refrigerant charge in a numerical table.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the refrigerant charge amount detection device for the refrigeration cycle of the present invention includes pressure detection for detecting the discharge pressure of the refrigerant in the discharge pipe of the low-pressure shell type compressor. Temperature detection means for detecting the refrigerant temperature at the outlet of the condenser is attached to the outlet pipe of the condenser. Further, the refrigerant filling amount detection device for a refrigeration cycle of the present invention includes a calculating means and a display means, and the calculating means is based on the discharge pressure and the refrigerant temperature at the condenser outlet to determine the degree of subcooling of the refrigerant at the outlet side of the condenser. is determined, the amount of refrigerant to be filled in when the degree of subcooling is approximately 1° C. is specified as an appropriate value, the filling rate of refrigerant to the refrigeration cycle is calculated based on the appropriate value, and the display means indicates the calculated amount. It is configured to numerically display the refrigerant filling rate.

[Operation] When there is a shortage of refrigerant in the refrigeration cycle, a gas-liquid two-phase refrigerant having a negative degree of supercooling is discharged from the condenser. As the amount of refrigerant in the refrigeration cycle increases, the degree of subcooling of the refrigerant increases, and the discharge pressure of the low-pressure shell type compressor also increases. When excess refrigerant is added, liquid refrigerant accumulates in the condenser, further increasing the degree of subcooling.

In the refrigerant filling amount detection device for a refrigeration cycle of the present invention, the discharge pressure of the low-pressure shell type compressor is detected by the pressure detection means attached to its discharge pipe, and the refrigerant temperature at the condenser outlet is detected by the temperature detection means. and those detection signals are manually input to the calculation means. The calculation means calculates the degree of supercooling of the refrigerant on the outlet side of the condenser based on the discharge pressure and the temperature of the refrigerant at the outlet of the condenser, and determines the degree of supercooling of the refrigerant on the outlet side of the condenser, and determines the degree of supercooling of the refrigerant on the outlet side of the condenser.
The amount of refrigerant to be filled in when this is specified is specified as an appropriate value, and the rate of refrigerant to be filled into the refrigeration cycle is calculated based on the appropriate value. Then, the calculated inclusion rate is displayed numerically by the display means.

Therefore, according to the apparatus for detecting the amount of refrigerant enclosed in a refrigeration cycle of the present invention, the mechanism for detecting the amount of enclosed refrigerant can be easily constructed using two detection means for pressure and temperature.

In addition, since the temperature detection means is attached to the outlet pipe of the condenser, unlike conventional temperature detectors installed in the middle of the condenser, accuracy is not degraded due to external thermal factors such as when clogging occurs. The appropriate amount of refrigerant can be accurately detected. Moreover, since the actual amount of refrigerant filled is clearly displayed numerically as a ratio to the appropriate value, refrigerant filling work such as when installing a refrigerator or air conditioner can be performed efficiently while visually checking the filling rate. I can do it.

[Example] Hereinafter, an example embodying the present invention will be described based on the drawings.

FIG. 1 is a block diagram schematically showing an embodiment of a refrigerant charge amount detection device for a refrigeration cycle according to the present invention, and FIG.
In the refrigeration cycle shown in the figure, the amount of refrigerant enclosed M and the degree of subcooling SC
FIG. 3 is a flowchart illustrating the operation of the refrigerant filling amount detection device of FIG. 1.

In FIG. 1, (1) is a low-pressure shell type compressor that adiabatically compresses the refrigerant in the refrigeration cycle, (2) is a condenser that condenses the refrigerant, (3) is an expansion mechanism that adiabatically expands the refrigerant,
(4) is an evaporator that evaporates refrigerant and exchanges heat with air. (1a) is a shell forming the outer shell of the low-pressure shell type compressor (1), and inside the shell is an electric motor (5).
) and compression chamber (6) are installed, as well as refrigerating machine oil (
7) is stored.

(8) is a discharge pipe that guides the high-pressure refrigerant gas discharged from the compression chamber (6) to the condenser (2), and (16) is the condenser (2).
(9) is an outlet pipe that leads the refrigerant discharged from the evaporator (4) to the expansion mechanism (3), and (9) is a suction pipe that leads the refrigerant discharged from the evaporator (4) to the low-pressure shell type compressor (1). The discharge pipe (8) is provided with a pressure sensor (10) that detects the discharge pressure of the refrigerant, and the outlet pipe (16) is equipped with a temperature sensor (15) that detects the refrigerant temperature at the condenser outlet. , suction tube (9
) is provided with a refrigerant sealing port (12).

(14) is a control panel that controls the entire refrigeration cycle, and is equipped with a microcomputer (11) equipped with calculation means, storage means, etc., and a display (13) that displays various data. ) are provided. The microcomputer (11) inputs detection signals from the pressure sensor (1o) and the temperature sensor (15),
It is configured to perform a predetermined calculation, which will be described later, based on the signal, and display the calculation result on the display (13).

Next, the operation of the refrigerant filling amount detection device for the refrigeration cycle of this embodiment configured as described above will be explained.

When installing a refrigerator or an air conditioner, refrigerant is charged into the refrigeration cycle from the refrigerant sealing port (12) while the refrigerator or air conditioner is in operation. When there is a shortage of refrigerant in the refrigeration cycle, as shown in FIG. 2, a gas-liquid two-phase refrigerant having a negative degree of supercooling sc is discharged from the condenser (2). The degree of subcooling SC of the refrigerant gradually increases as the amount M of refrigerant increases, and thereby the discharge pressure of the low pressure shell type compressor (1) also increases. Then, when excess refrigerant is added, liquid refrigerant accumulates in the condenser (2) and the degree of supercooling SC further increases, but the enthalpy on the inlet side of the evaporator (4) decreases, causing the evaporation pressure and low pressure. The suction pressure of the shell type compressor (1) decreases. Therefore, when the degree of subcooling SC of the refrigerant is approximately 1°C, the total amount of refrigerant enclosed ΣM is:
This corresponds to the appropriate amount of refrigerant sealed in the refrigeration cycle.

In this embodiment, the degree of subcooling SC of the refrigerant, the appropriate amount of refrigerant ΣM1, and the refrigerant filling rate C are determined by the microcomputer (11) as follows.

In the flowchart of FIG. 3, first, step S1
Then, a predetermined amount (J
Mkg) of refrigerant is sealed. Next, in step S2, the discharge pressure Pd of the low pressure shell type compressor (1) at that time is detected by the pressure sensor (10), and the refrigerant temperature T on the outlet side of the condenser (2) is detected by the temperature sensor (10).
5). Subsequently, in step S3, based on the discharge pressure Pd and the refrigerant temperature T at the condenser outlet,
The degree of supercooling SC of the refrigerant is determined using the following formula: SC-·Saturation temperature-Refrigerant temperature depth f(Pd)-T (f is a function).

In step S4, it is determined whether the degree of subcooling SC of the refrigerant is 1°C. Due to lack of refrigerant during the refrigeration cycle,
If the judgment result is No, repeat step S1 again.
Then, JM kg of refrigerant is sealed, and in step S2, the discharge pressure Pd and the refrigerant temperature T at the condenser outlet are detected.

In this way, when the amount M of refrigerant enclosed in the refrigeration cycle increases and the degree of supercooling SC reaches 1°C, the judgment result in step S4 becomes YES, and the next step S5
Then, the absolute amount of refrigerant input ΣM at that time is specified as the appropriate amount of refrigerant, and is stored in the storage means of the microcomputer (11).

In step S6, the refrigerant filling rate C is calculated based on the absolute filling amount ΣM, the subsequent additional filling amount, and dM using the formula C=(ΣM+kJM)/ΣM. Then, in step S7, the calculated value of the inclusion rate C is displayed on the display (13) as a numerical value such as 1.0 if it is appropriate and 1.1 if it is excessive.

As described above, in the refrigerant charge amount detection device for the refrigeration cycle of this embodiment, a pressure sensor is installed in the discharge pipe (8) of the low-pressure shell type compressor (1) as a pressure detection means for detecting the discharge pressure Pd of the refrigerant. (10) is provided, and
The outlet pipe (16) of the condenser (2) is equipped with a temperature sensor (1) as a temperature detection means for detecting the refrigerant temperature T at the outlet of the condenser.
5) is installed. In addition, the refrigerant filling amount detection device for the refrigeration cycle of this embodiment includes a microcomputer (11) as a calculation means and a display (11) as a display means.
3), the microcomputer (11) determines the degree of subcooling SC of the refrigerant on the outlet side of the condenser (2) based on the discharge pressure Pd and the refrigerant temperature T at the outlet of the condenser, and calculates the degree of subcooling. Absolute amount of refrigerant input ΣM when SC is approximately 1°C
is specified as an appropriate value, the refrigerant filling rate C in the refrigeration cycle is calculated based on the appropriate value, and the display device (13) is configured to display the calculated refrigerant filling rate C numerically. It is something.

Therefore, according to the refrigerant filling amount detection device for the refrigeration cycle of this embodiment, the pressure sensor (10) and the temperature sensor (1
The two detecting means (5) allow a simple configuration of the enclosure amount detection mechanism. In addition, the temperature sensor (15) is connected to the condenser (2)
Because it is attached to the outlet pipe (16) of the condenser, unlike conventional temperature detectors installed in the middle of the condenser, there is less risk of deterioration in accuracy due to external thermal factors such as when clogging occurs. The appropriate amount of refrigerant can be accurately detected. Moreover,
Since the actual amount of refrigerant filled is clearly displayed numerically as a ratio to the appropriate value, refrigerant filling work such as when installing a refrigerator or air conditioner can be performed efficiently while visually checking the filling rate. .

[Effects of the Invention] As described above, the refrigerant filling amount detection device for a refrigeration cycle of the present invention includes a pressure detection means for detecting the discharge pressure of a low-pressure shell type compressor, and a temperature detection means for detecting the refrigerant temperature at the condenser outlet. means, a calculation means for calculating the filling rate of refrigerant into the refrigeration cycle based on the appropriate value, with the amount of refrigerant filled when the degree of subcooling of the refrigerant at the condenser outlet is approximately 1° C.; Since it is equipped with a display means for numerically displaying the encapsulation rate, it is possible to easily configure a detection mechanism for the encapsulation amount using two detection means of pressure and temperature, and it also prevents accuracy from decreasing due to external thermal factors. It is possible to accurately detect the proper amount of refrigerant filled in, and also to clearly display numerically the actual amount of refrigerant filled in as a ratio to the appropriate value, making it possible to efficiently fill refrigerant during installation, etc. effective.

[Brief explanation of drawings]

FIG. 1 is a block diagram schematically showing an embodiment of a refrigerant charge amount detection device for a refrigeration cycle according to the present invention, and FIG.
FIG. 3 is a characteristic diagram showing the relationship between the amount of refrigerant charged and the degree of subcooling in the refrigeration cycle shown in FIG. Fig. 4 shows an indoor unit of an air conditioner equipped with a refrigerant filling amount detection device for a refrigeration cycle according to the first conventional example, and Fig. 4(a) is a front view;
Figure (b) is a side view. FIG. 5 is a block diagram schematically showing a second conventional refrigerant charge amount detection device for a refrigeration cycle. In the figure, 1: low pressure shell type compressor 8: discharge pipe 10: pressure sensor 11: microcomputer 13: display 15: temperature sensor 16: outlet pipe. In the drawings, the same reference numerals and the same symbols indicate the same or equivalent parts.

Claims (1)

[Claims] (1) Attached to the discharge pipe of a low pressure shell type compressor,
pressure detection means for detecting the discharge pressure of the refrigerant; temperature detection means attached to the outlet pipe of the condenser for detecting the temperature of the refrigerant at the outlet of the condenser; Determine the degree of supercooling of the refrigerant on the outlet side, and find that the degree of supercooling is approximately 1.
℃, and calculates the refrigerant filling rate into the refrigeration cycle based on the appropriate value, and the calculating means calculates the refrigerant filling rate calculated by the calculating means as a numerical value 1. A refrigerant filling amount detection device for a refrigeration cycle, comprising: display means for displaying a display.