JPS62142971A - Detector for proper quantity of refrigerant filled - 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 an appropriate refrigerant amount detection device for an air conditioner.

[Conventional technology]

FIG. 6 is a block diagram of a refrigerant circuit of a conventional heat pump air conditioner disclosed in Japanese Utility Model Application No. 155055/1980.

In this Fig. 6, the refrigerant circuit consists of a compressor 1 degree four-way valve 2
．． Outdoor heat exchanger 3. Capillary tube for reducing pressure 4. Indoor heat exchanger5.
It is composed of an accumulator 6, and each part is connected by refrigerant piping.

Next, the operation during cooling will be explained. In the refrigerant circuit shown in FIG. 6, high temperature, high pressure gas refrigerant discharged from the compressor 1 passes through the four-way valve 2 and is supplied to the outdoor heat exchanger 3.

In this outdoor heat exchanger 3, heat exchange with outdoor air is performed, and the gas refrigerant is cooled and condensed, changing from a high-pressure two-phase state to a high-pressure supercooled liquid refrigerant.

This high-pressure supercooled refrigerant is depressurized in the process of passing through the pressure-reducing capillary tube 4, becomes a low-pressure two-phase state, and is supplied to the indoor heat exchanger 5.

In the indoor heat exchanger 5, heat is exchanged with indoor air, and the low-pressure two-phase refrigerant changes to a dry low-pressure two-phase state or heated gas refrigerant, and passes through the four-way valve 2 to the accumulator 6. is supplied and sucked into the compressor 1. By repeating this cycle, the indoor air is cooled and air conditioning is performed.

On the other hand, during heating, the refrigerant discharged from the compressor 1 is first supplied to the outdoor heat exchanger 3 via the indoor heat exchanger 5, then the decompression capillary tube 4, contrary to the above-mentioned cooling time.
Four-way valve 2. It passes through the accumulator 6 and is sucked into the compressor 1.

The outdoor heat exchanger 3 operates as an evaporator, while the indoor heat exchanger 5 operates as a condenser, and by repeating the above cycle, indoor air is warmed and space heating is performed.

Furthermore, in the refrigerant circuit that performs the cooling/heating cycle, changes in the cycle operating state due to changes in the refrigerant filling amount are
This will be explained using figures.

This Fig. 7 is a two-line diagram with refrigerant pressure P (kg/crA) on the vertical axis and enthalpy (Kcal/kg) on the horizontal axis. The cycles indicated by (dashed line) and r3J (dashed line) respectively indicate operating states when the refrigerant charge amount is appropriate, too little, and too much.

In addition, SH (super heat) in the figure refers to the degree of superheating of the suction refrigerant of compressor l, X represents the degree of dryness when the suction refrigerant is in a two-phase state, and SC (subcool) refers to the heat exchanger that operates as a condenser. The degree of supercooling of the liquid refrigerant at the outlet, Td is the discharge refrigerant temperature of the compressor 1, and Pd and Ps are the discharge pressure and suction pressure of the compressor 1, respectively.

From the same figure, the relationship between the respective values is: SH+ < SHz (In the case of "3" in the figure, the suction refrigerant is two-phase and SH3 does not exist) sc2 < sc,
<sc.

Td3<Td,<T'd2 Pd, <Pd, <Pd3 Psz <Ps, <Ta2 It becomes.

In contrast to cycle ``1'' when the refrigerant charging amount is appropriate, cycle ``2'' when the refrigerant charging amount is too low indicates an operating state in which the air conditioning capacity is insufficient or the discharge temperature rises too much, and the refrigerant charging In cycle "3" when the amount is excessive, the refrigerant sucked into the compressor is in a two-phase state, and the operating state is such that so-called liquid compression occurs in the compressor cylinder.
Both are unfavorable for compressor operation.

[Problem that the invention seeks to solve]

Conventional air conditioners are configured as described above, and the amount of refrigerant is filled at the installation site using a weighing machine, cylinder, etc. while the compressor is running, so it is possible to fill the refrigerant with sufficient accuracy. First, there are problems in that the air conditioner is not used in an appropriate operating state, or the conditions for determining whether the air conditioner is in an appropriate operating state are not clear.

This invention was made in order to solve such problems. Among the operating conditions of the refrigerant circuit, the suction condition of the compressor can be accurately detected, and an appropriate refrigerant can be used to fill the air conditioner with the necessary and sufficient amount of refrigerant. The purpose is to obtain a filling amount detection device.

[Means for solving problems]

The appropriate refrigerant filling amount detection device according to the present invention is configured to connect a first bypass pipe, two capillary tubes, and a second bypass pipe in series, and to exchange heat between the first bypass pipe and the second bypass pipe. A first refrigerant temperature sensor is provided in the suction pipe, a second refrigerant temperature sensor is provided in the heat exchange section on the second bypass pipe, and the first refrigerant temperature sensor and the second refrigerant temperature sensor are connected to each other. This device is equipped with a device that performs arithmetic processing on the temperature detected by the device.

[For production]

In this invention, a part of the high-temperature, high-pressure superheated gas refrigerant in the discharge pipe of the compressor is passed through the first bypass pipe, and the pressure is kept constant by exchanging heat with the second bypass pipe in the heat exchange section. The cooled, high-pressure two-phase state or supercooled liquid refrigerant state is depressurized by a capillary tube, and the refrigerant is brought to a low-pressure two-phase state and passed through the second bypass pipe, exchanging heat with the first bypass pipe during the passage process. The temperature of the suction pipe is detected by the first refrigerant temperature detector, and the temperature of the suction pipe is detected by the first refrigerant temperature detector, and the temperature of the suction pipe is 2, which is equal to the suction pressure of the heat exchange section of the second bypass pipe. The saturated evaporation temperature of the phase refrigerant is detected by the second refrigerant temperature detector, and the rain detection information is processed by the arithmetic unit.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the appropriate refrigerant filling amount detection device of the present invention will be described based on the drawings. FIG. 2 is a configuration diagram of a refrigerant circuit of an air conditioner main body to which one embodiment of the present invention is applied. In FIG. 1, the same parts as in FIG. 6 are given the same reference numerals.

The main body of the air conditioner shown in FIG. 2 includes a compressor 1. Four-way valve 2.
Outdoor heat exchanger 3. Capillary tube for reducing pressure 4. Indoor heat exchanger5. It is constructed by connecting the accumulator 6 with refrigerant pipes 7a to 7g. Further, 8 indicates a discharge boat, and 9 indicates a suction boat.

As shown in FIG. 1, the discharge boat 8 is connected to a discharge bypass port 1), and the suction boat 9 is connected to a suction bypass port 12. FIG. 1 shows the configuration of the appropriate refrigerant filling amount detection device of the present invention.

As is clear from this Figure 1, the discharge bypass port I
A first bypass pipe I3 is connected to I, and a second bypass pipe 14 is connected to the suction bypass port 12.

As shown in the figure, the first bypass piping 13 and the second bypass piping 14 are closely fixed for a predetermined length to form a heat exchange section so as to exchange heat at predetermined locations.

This first bypass piping 13 and second bypass piping】4
A capillary tube 15 is connected between the other ends.

On the other hand, 16 is a first refrigerant temperature detector, which is installed between the suction boat 9 and the four-way valve 2 on the suction pipe 7f. The detection power of the first refrigerant temperature detector 16 is sent to the arithmetic unit 18.

Further, a second refrigerant temperature detector 17 is provided on the second bypass pipe 14 of the heat exchange section. The detected power of this second refrigerant temperature detector 17 is sent to an arithmetic unit 18.

The calculation device 18 inputs the detection power of the first refrigerant temperature detector 16 and the second refrigerant temperature detection power, performs calculation processing,
It is configured to output to an output device 19.

Next, the operation of this invention will be explained. First, the operation of the air conditioner body shown in FIG. 2 will be explained. For example, in the case of cooling operation, the high temperature and high pressure gas refrigerant discharged from the pressure '4'r6 machine 1 enters the discharge pipe 7a, the four-way valve 2, the pipe 7b, and the outdoor heat exchanger 3, where it condenses and becomes liquid. It becomes a refrigerant and reaches the pipe 7c.

Furthermore, the pressure is reduced by the decompression capillary tube 4, and the refrigerant enters the indoor heat exchanger 5 through the pipe 7d, where the refrigerant is evaporated to produce a refrigerant effect.
．． The refrigerant reaches the accumulator 6 via the piping 7f, stores surplus refrigerant there, and is sucked into the compressor l through the piping 7g, forming a heat pump type refrigeration cycle.

When the apparatus of the present invention shown in FIG. 1 is installed in such an air conditioner main body, a part of the discharged refrigerant passes through the discharge pipe 7a, the discharge boat 8, the discharge bypass boat ll, and the first bypass pipe 131. Capillary tube 15, second bypass piping 1
4. Inhalation bypass port 12. A bypass circuit is formed in which the air passes through the suction boat 9 and returns to the suction pipe 7f.

At this time, the high-temperature, high-pressure superheated gas refrigerant is cooled in the process of passing through the first bypass pipe 13 by exchanging heat with the low-temperature refrigerant whose pressure has been reduced in the capillary tube 15 in the heat exchange section, and is brought into a high-pressure two-phase state. Or it becomes a supercooled liquid refrigerant, and the capillary tube 15
leading to the entrance.

This high-pressure refrigerant is depressurized by the capillary tube 15, and the low-pressure refrigerant is
In the process of becoming a phase refrigerant and passing through the second bypass pipe I4,
A cycle is formed in which the gas is heated by exchanging heat in the heat exchange section, has almost the same enthalpy as the discharged gas, and returns to the suction pipe 7f.

FIG. 3 is a Mollier diagram showing the above operation, with enthalpy i plotted on the horizontal axis and pressure P plotted on the vertical axis, showing a cycle using a refrigerant bypass circuit.

In FIG. 3, rlJ and r2J are the refrigerant i at the inlet and outlet of the first bypass pipe 13, respectively.

It represents p.

Moreover, "3" and r5J are respectively the second bypass piping 1
"4" represents the refrigerant i and p at the position where the second refrigerant temperature sensor 17 is provided.

As is clear from FIG. 3, the saturation temperature relative to the suction refrigerant pressure, that is, the saturated evaporation temperature, is detected at position "4". This saturated evaporation temperature does not depend on the amount of refrigerant charged and always indicates the saturated temperature with respect to the suction pressure.

On the other hand, the first refrigerant temperature detector 16 provided in the suction pipe 7'' detects the temperature of the suction refrigerant, and this suction temperature changes as shown in FIG. 4 with respect to the refrigerant filling amount.

This Figure 4 shows the suction refrigerant temperature on the vertical axis and the refrigerant charging amount on the horizontal axis. Point A in the figure is the optimal refrigerant charging amount, and when the refrigerant charging amount is small due to this point A, The suction refrigerant temperature is always higher than the saturated evaporation temperature, and is sucked in with a certain degree of superheat (difference between the suction refrigerant temperature and the saturated evaporation temperature).

Furthermore, when the amount of refrigerant charged is larger than point A, surplus refrigerant is generated and stored in the accumulator trough as liquid refrigerant, so the suction temperature due to two-phase refrigerant flowing through the suction pipe 7f is the saturated evaporation temperature. is equal to

Therefore, when charging the refrigerant while operating the air conditioner main body, the intake refrigerant temperature and the saturated evaporation temperature are detected by the first and second refrigerant temperature detectors 16 and 17, respectively, and converted into electrical signals. The arithmetic unit 18 compares the two, and when the two temperature values are exactly equal, the optimum amount of refrigerant is determined, and an electric signal is sent to the output device 19.

This output device 19 can detect the optimum refrigerant charging amount by, for example, lighting a lamp or the like.

Note that in the above embodiment, the first bypass pipe 13 and the second
Although the heat exchange section of the bypass pipe 14 is brought into contact with the heat exchange section of the bypass pipe 14 for a predetermined length and fixed by brazing or the like, as shown in FIG. Even if heat exchange is performed using a double pipe system arranged inside the pipe 14, the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As explained above, this invention is configured such that a refrigerant bypass circuit having a heat exchange section is attached to the main body of a normal air conditioner, and the saturated evaporation temperature can be generated and detected, making it possible to accurately charge additional refrigerant at low cost. This has the effect of being able to be carried out at the installation site.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the appropriate refrigerant charging amount detection device of the present invention, and FIG. 2 is a diagram showing the configuration of a refrigerant circuit of an air conditioner body to which the above-mentioned appropriate refrigerant charging amount detection device is applied.
Fig. 3 is a bypass cycle Mollier diagram for explaining the operation of the appropriate refrigerant charge amount detection device as above, and Fig. 4 shows the intake refrigerant temperature and refrigerant charge amount for explaining the operation of the above appropriate refrigerant charge amount detection device. FIG. 5 is a diagram showing the configuration of another embodiment of the appropriate refrigerant filling amount detection device of the present invention, FIG. 6 is a diagram showing the configuration of a refrigerant circuit of a conventional air conditioner, and FIG. 7 is a diagram showing the relationship. is a Mollier diagram showing changes in operating conditions depending on the amount of refrigerant charged in a conventional air conditioner. 1... Compressor, 2... Four-way valve, 3... Outdoor unit, 4
...Capillary tube for depressurization, 5...Indoor heat exchanger, 6...
Accumulator, 13...first bypass piping, 14
...Second bypass piping, 15...Capillary tube, 16.
. . . first refrigerant temperature detector, 17 . . . second refrigerant temperature detector, 18 . . . arithmetic device, 19 .

Claims (3)

[Claims] (1) In an air conditioner having a refrigerant circuit configured by sequentially connecting a compressor, a four-way valve, an outdoor heat exchanger, a decompression capillary, an indoor heat exchanger, and an accumulator with refrigerant piping, the discharge piping of the compressor a first bypass pipe whose one end is connected to the suction pipe of the compressor, a second bypass pipe whose one end is connected to the suction pipe of the compressor and forms a heat exchange section with the first bypass pipe, and the first and second bypass pipes. A capillary tube connected between the other ends of the piping, a first refrigerant temperature detector installed on the piping connecting the accumulator and the four-way valve to detect the refrigerant temperature of this piping, and a first refrigerant temperature detector on the second bypass piping. a second detecting the saturated evaporation temperature of the refrigerant in the heat exchange section;
An appropriate refrigerant filling amount detection device comprising: a refrigerant temperature detector; and an arithmetic unit that processes temperature information detected by the first and second refrigerant temperature detectors. (2) The appropriate refrigerant filling amount detection device according to claim 1, wherein the heat exchange section is constructed by closely fixing the first and second bypass pipes to a predetermined length. (3) The appropriate refrigerant filling amount detection device according to claim 1, wherein the heat exchange section has a double pipe structure in which the first bypass pipe is inserted into the second bypass pipe.