JPH0610571B2 - Appropriate refrigerant filling amount detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a proper refrigerant capable of accurately checking whether or not the operation of the air conditioner is improved with the accuracy of additional refrigerant charging or an appropriate amount of refrigerant. The present invention relates to a filling amount detection device.

[Conventional technology]

FIG. 6 shows a conventional proper refrigerant charge amount detection device shown in Japanese Patent Application No. 60-285017, and FIG. 7 is a refrigerant circuit configuration diagram in a state where it is installed in an air conditioner. FIG. 7 shows a compressor 1
-Refrigerant pipe 7a-Four-way valve 2-Refrigerant pipe 7b-Outdoor heat exchanger 3-Refrigerant pipe 7c-Capillary pipe for pressure reduction 4-Refrigerant pipe 7d-
Indoor heat exchanger 5-refrigerant pipe 7e-four-way valve 2-refrigerant pipe 7
This is a refrigerant circuit configuration in which f-accumulator 6-refrigerant pipe 7g-compressor 1 are sequentially connected.

The discharge port 8 and the suction port 9 are connected to the bypass ports 11 and 12 of the proper refrigerant amount detection device 21 by a refrigerant pipe.

FIG. 6 shows the first bypass pipe 13, the second bypass pipe 14, the capillary pipe 15, the first refrigerant temperature detector 16, the second refrigerant temperature detector 17, the temperature information input device 18, the arithmetic device 19, and the arithmetic operation. The proper refrigerant amount detection device 21 including the output device 20 of the result is shown. First bypass pipe 13
The second bypass pipe 14 and the second bypass pipe 14 are fixed so as to be in close contact with each other for a predetermined length so as to exchange heat with each other to form a heat exchange portion.

Next, the operation will be described. For example, the operation of the air conditioner main body in the case of the cooling operation will be described first. The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 enters the outdoor heat exchanger 3 through the refrigerant pipe 7a, the four-way valve 2 and the refrigerant pipe 7b, and is condensed there to become a high-pressure liquid refrigerant and reach the refrigerant pipe 7c.

Further, the pressure is reduced by the pressure reducing capillary 4, and the refrigerant pipe 7d
To the indoor heat exchanger 5, where the refrigerant effect is produced by evaporating the refrigerant, and further reaches the accumulator 6 via the refrigerant pipe 7e, the four-way valve 2, and the refrigerant pipe 7f.
Therefore, a heat pump type refrigeration cycle in which surplus refrigerant is stored and taken into the compressor 1 through the refrigerant pipe 7g is configured.

When the proper refrigerant amount detection device 21 of FIG. 6 is installed in this air conditioner, a part of the discharged refrigerant passes from the refrigerant pipe 7a through the discharge port 8 to the discharge bypass port 11 to the first bypass pipe 13 and the capillary tube. 15, the second bypass pipe 14,
A bypass circuit is formed that returns to the refrigerant pipe 7f via the suction bypass port 9.

At this time, the high-temperature and high-pressure superheated gas refrigerant is cooled by exchanging heat with the low-temperature refrigerant decompressed by the capillary tube 15 in the heat exchange section in the process of passing through the first bypass pipe 13, and becomes a high-pressure two-phase state. It reaches the entrance of the capillary tube 15. This high-pressure refrigerant is decompressed by the capillaries 15 to become a low-pressure two-phase refrigerant, which is heated by heat exchange in the heat exchange section in the process of passing through the second bypass pipe 14 and becomes an enthalpy almost the same as the discharge gas. A cycle of returning to the pipe 7f constitutes a cycle.

At this time, the second refrigerant temperature detector 17 provided at the inlet of the second bypass pipe 14 detects the saturation temperature with respect to the compressor suction pressure, that is, the saturated evaporation temperature.

This saturated evaporation temperature does not depend on the refrigerant charge amount 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 refrigerant pipe 7f detects the temperature of the sucked refrigerant, and this sucked temperature changes with respect to the refrigerant charge amount as shown in FIG.

In FIG. 8, the vertical axis represents the intake refrigerant temperature and the horizontal axis represents the refrigerant charge amount. Point A in the figure is the optimum refrigerant charge amount, and the intake refrigerant temperature decreases as the refrigerant charge amount decreases from this point A. Becomes higher and is sucked with a certain degree of superheat (= intake refrigerant temperature−saturated evaporation temperature).

Further, when the refrigerant charge amount is larger than the point A, excess refrigerant is generated and stored in the accumulator 7 as a liquid refrigerant,
Since the two-phase refrigerant flows through the refrigerant pipe 7f, the suction temperature becomes equal to the saturated evaporation temperature.

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 electric signals, The calculation device 19 compares the temperature information input device 18 with each other, and when the two temperatures are exactly equal, the optimum refrigerant amount is determined, and an electric signal is sent to the output device 20.

[Problems to be solved by the invention]

The conventional appropriate refrigerant filling amount detection device is configured as described above, and the refrigerant filling amount cannot be found unless the refrigerant is gradually filled from a small point, and the refrigerant is already filled with the refrigerant. If the suction temperature shows a value equal to the saturated evaporation temperature, it cannot be determined whether the refrigerant charge amount is appropriate.

That is, there is a problem that the lower limit refrigerant charge amount can be detected but the upper limit refrigerant charge amount cannot be detected.

The present invention has been made to solve such a problem, and accurately detects the suction state and the discharge state of the compressor as the operating state of the refrigerant circuit, and also detects the lower limit and the upper limit of the proper refrigerant amount. An object of the present invention is to obtain a reliable and reliable proper refrigerant charge amount detection device.

[Means for solving problems]

A proper refrigerant filling amount detection device according to the present invention includes a refrigerant bypass circuit having a heat exchange section, in which a first bypass pipe, a capillary tube, and a second bypass pipe are sequentially connected in series, and a refrigerant pipe on a discharge side of a compressor. A first refrigerant temperature detector, a second refrigerant temperature detector provided in the suction side refrigerant pipe of the accumulator, and a third refrigerant temperature detector provided in the heat exchange section outlet of the first bypass pipe. A refrigerant temperature detector, a fourth refrigerant temperature detector provided at the inlet of the heat exchange section on the second bypass pipe, and an arithmetic unit processing the outputs of the first to fourth refrigerant temperature detectors are provided. It is a thing.

[Action]

In the present invention, a part of the high-temperature, high-pressure gas refrigerant in the refrigerant pipe on the discharge side of the compressor is passed through the first bypass pipe, and heat is exchanged with the second bypass pipe at the heat exchanging section to keep the pressure constant. It is cooled as it is to be in a high-pressure two-phase state, which is decompressed by a capillary tube, is made into a low-pressure two-phase state, is passed through a second bypass pipe, and is overheated by exchanging heat with the first bypass pipe in the passing process Is returned to the suction-side refrigerant pipe as superheated gas equal to the suction pressure, and the discharge gas refrigerant temperature, the suction refrigerant temperature, the saturated condensation temperature, and the saturated evaporation temperature are detected by the first to fourth refrigerant temperature detectors, respectively. The detection information is processed by the arithmetic device.

〔Example〕

An embodiment of the proper refrigerant filling amount detection device of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of one embodiment thereof, and FIG. 2 is a refrigerant circuit configuration diagram in a state in which it is mounted on an air conditioner.

First, FIG. 2 will be described. In FIG. 2, the same parts as those in FIG. 7 are designated by the same reference numerals. This FIG. 2 shows a compressor 1-refrigerant pipe 7a-four-way valve as a switching valve 2-refrigerant pipe 7b-outdoor heat exchanger 3-refrigerant pipe 7c.
-Decompression capillary tube 4-Refrigerant pipe 7d-Indoor heat exchanger 5-Refrigerant pipe 7e-Four-way valve 2-Refrigerant pipe 7f-Accumulator 6-Refrigerant pipe 7a-Refrigerant circuit configuration of an air conditioner in which compressor 1 is sequentially connected. FIG.
The suction port 9 and the bypass ports 11 and 12 of the proper refrigerant amount detection device 21 are connected by refrigerant pipes, respectively.

FIG. 1 is a view showing the main body of the proper refrigerant filling amount detection device 21, in which a first bypass pipe 13 is connected to the discharge bypass port 11 and a second bypass pipe 14 is connected to the suction bypass port 12. ing.

The first bypass pipe 13 and the second bypass pipe 14 form a heat exchange portion by closely adhering and fixing a predetermined length as shown so that a predetermined amount of heat is exchanged at a predetermined location.

The first bypass pipe 13 and the second bypass pipe 14
A capillary tube 15 is connected between the other ends of and.

On the other hand, 16a is a first refrigerant temperature detector, which is mounted on the discharge side refrigerant pipe 7a. A second refrigerant temperature detector 16b is mounted on the suction side refrigerant pipe 7f between the suction bypass port 9 and the four-way valve 2.

Further, a third refrigerant temperature detector 17a is attached to the heat exchange section outlet on the first bypass pipe 13 and a fourth refrigerant temperature detector is attached to the heat exchange section inlet on the second bypass pipe 14. A temperature detector 17b is attached.

The first to fourth refrigerant temperature detectors 16a, 16b, 17
The temperature information from a and 17b is collected by the temperature information input device 18 and sent to the arithmetic device 19.

The arithmetic device 19 performs arithmetic processing on the temperature information sent from the temperature information input device 18, and outputs it to the output device 20.

Next, the operation of the present invention will be described. First, in the operation of the air conditioner main body, for example, in the case of cooling operation, the high temperature and high pressure gas refrigerant discharged from the compressor 1 is discharged on the refrigerant pipe 7 side.
a through the four-way valve 2 and the refrigerant pipe 7b, and the outdoor heat exchanger 3
And condensed here to become a high-pressure liquid refrigerant, which is decompressed in the process of passing through the refrigerant pipe 7c and the pressure-reducing capillary tube 4, enters the indoor heat exchanger 5 through the refrigerant pipe 7d, and evaporates the refrigerant here. To produce a freezing effect.

Further, the refrigerant pipe 7e, the four-way valve 2, the suction side refrigerant pipe 7
A heat pump type refrigeration cycle in which the refrigerant reaches the accumulator 6 via f, stores the excess refrigerant therein, and is sucked into the compressor 1 through the refrigerant pipe 7g is configured.

When the proper refrigerant filling amount detection device of the first aspect of the present invention is mounted on such an air conditioner main body, a part of the discharged refrigerant is discharged from the discharge port 8 through the discharge bypass port 11 from the discharge side refrigerant pipe 7a. After that, the first bypass pipe 13, the capillary pipe 15, the second bypass pipe 14, the suction bypass port 1
2. A bypass circuit is formed that returns to the refrigerant pipe 7f on the suction side through the suction port 9.

At this time, the high-temperature and high-pressure superheated gas refrigerant is cooled by exchanging heat with the low-temperature refrigerant decompressed by the capillary tube 15 in the heat exchange section in the process of passing through the first bypass pipe 13, and is in a high-pressure two-phase state. And reaches the entrance of the capillary tube 15.

This high-pressure refrigerant is decompressed by the capillary tube 15,
It becomes a phase refrigerant and is heated by exchanging heat in the heat exchanging portion in the process of passing through the second bypass pipe 14, and becomes an enthalpy almost the same as the discharge gas and returns to the refrigerant pipe 7f on the suction side, which constitutes a cycle.

FIG. 3 is a Mollier diagram showing the above operation, in which the horizontal axis shows the enthalpy i and the vertical axis shows the pressure p, showing the cycle by the refrigerant bypass circuit.

(1) and (2) in FIG. 3 represent the refrigerant i and p at the inlet and outlet of the first bypass pipe 13, respectively.

Further, (3) and (4) represent the refrigerant i and p at the inlet and outlet of the second bypass pipe 14, respectively. In particular
(2) and (3) are the third and fourth refrigerant temperature detectors 1 respectively
It shows i and p of the refrigerant at the positions where 7a and 17b are provided.

As can be seen from FIG. 3, the saturation temperature with respect to the discharge refrigerant pressure is detected at the position (2), and the saturation temperature with respect to the suction refrigerant pressure, that is, the saturated evaporation temperature is detected at the position (3).

These saturated condensation temperature and saturated evaporation temperature always show the saturation temperature with respect to the discharge pressure and the suction pressure, without depending on the refrigerant charge amount.

On the other hand, the first refrigerant temperature detector 16a provided on the discharge side refrigerant pipe 7a detects the discharged refrigerant temperature, and the second refrigerant temperature detector 16b provided on the suction side refrigerant pipe 7f.
Detects the intake refrigerant temperature, and the discharge refrigerant temperature and the intake refrigerant temperature change as shown in FIG. 4 in response to changes in the refrigerant charge amount.

In FIG. 4, the vertical axis represents the refrigerant temperature and the horizontal axis represents the refrigerant filling amount. The same figure also shows changes in the saturated condensation temperature and the saturated evaporation temperature.

Refrigerant charge amount W corresponding to arrows A and B in FIG.
_A and W _B are lower refrigerant charge and maximum refrigerant charging amount is determined to be proper, respectively.

In the figure, the solid line shows the discharge refrigerant temperature, the one-dot chain line shows the saturated condensation temperature, the two-dot chain line shows the intake refrigerant temperature, and the broken line shows the saturated evaporation temperature.The difference between the intake temperature and the saturated evaporation temperature is shown in the intake superheat. SHs and the difference between the discharge temperature and the saturated condensation temperature are defined as discharge superheat SHd.

When less refrigerant charge than the lower refrigerant quantity W _A is sucked gas refrigerant is sucked into the compressor with the always suction superheat SHs. Further, the discharge superheat SHd also has a large value. That is, the overheat operation is performed with a shortage of the refrigerant amount. The closer to the W _A by increasing the refrigerant charge, to the suction superheat SHs is 0, the discharge superheat S
Hd approaches a certain fixed value.

When the refrigerant charge amount is between W _A and W _B , the intake SHs
Is always 0, and the discharge superheat SHd is always a constant value. This is because the operation state does not change because the liquid refrigerant is stored in the accumulator 6.

Further, when larger than W _B increased refrigerant charge, will not be sufficiently accumulated in the accumulator 6, the discharge temperature is lowered by a large amount of liquid refrigerant is sucked into the compressor 1 from the refrigerant pipe 7g on the suction side, the discharge super The heat SHd also drops sharply.

At this time, the suction superheat SHs remains 0. This is a so-called liquid return operation, which adversely affects the compressor 1.

Therefore, the refrigerant filling amount between W _A and W _B is a proper refrigerant filling amount, and the determination condition of being appropriate is SHd = SHd ₀ (1) SHs = 0 ... As can be seen from FIG. … (2).

It is necessary that the above equations (1) and (2) are satisfied at the same time.
SHd ₀ is the discharge superheat at the proper refrigerant charge amount, shows the same value even when the operating conditions change, and is approximately SHd = 40 (deg).

When the refrigerant is filled while the air conditioner is being operated or is being operated, the discharge temperature and the saturation condensation temperature are detected by the first and third refrigerant temperature detectors, respectively, and the intake temperature and The saturated evaporation temperature is detected by the second and fourth refrigerant temperature detectors, respectively,
These are converted into electric signals, collected by the temperature information input device 18, compared and calculated by the calculation device 19, and the condition of the above formula (1) is that the temperature values detected by the first and third refrigerant temperature detectors are exactly the same. The condition of the above equation (2) is that the difference between the temperatures detected by the second and fourth refrigerant temperature detectors becomes equal to SHd ₀ .

At this time, the optimum refrigerant filling amount is set, and an electric signal is sent to the output device 20. The output device 20 can detect the optimum refrigerant charge amount by turning on a lamp, for example.

In addition, the above-mentioned embodiment uses the first bypass pipe 13 and the second bypass pipe 13.
Although the heat exchange part of the bypass pipe 14 is contacted for a predetermined length and fixed by brazing or the like, as shown in FIG. 5, the first bypass pipe 13 is used as the heat exchange part and the second bypass pipe 14 is used as the heat exchange part. Even if the heat exchange can be performed by the double pipe system configured to be arranged inside 14, the same effect as that of the above-described embodiment can be obtained.

〔The invention's effect〕

As described above, according to the present invention, the normal air conditioner main body is equipped with the refrigerant bypass circuit having the heat exchange section, and is configured to generate and detect the saturated condensation temperature and the saturated evaporation temperature. There is an effect that charging can be performed and whether or not the refrigerant charging amount of the operating air conditioner is appropriate can be determined, and that it can be performed at a low cost at the installation site.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a proper refrigerant filling amount detection device of the present invention, and FIG. 2 is a diagram showing a configuration of a refrigerant circuit of an air conditioner body equipped with the same proper refrigerant filling amount detection device,
FIG. 3 is a bypass cycle Mollier diagram for showing the operation of the proper refrigerant filling amount detection device of the above, and FIG. 4 is a relationship between the refrigerant temperature and the refrigerant filling amount for explaining the operation of the proper refrigerant filling amount detection device of the same. FIG. 5, FIG. 5 is a diagram showing the configuration of another embodiment of the proper refrigerant filling amount detection device of the present invention, FIG. 6 is a diagram showing the configuration of a conventional proper refrigerant filling amount detection device, and FIG. FIG. 8 is a diagram showing a configuration of a refrigerant circuit when the appropriate refrigerant filling amount detection device of FIG. 2 is mounted on an air conditioner body, and FIG. 8 is a diagram showing a relationship between a suction refrigerant temperature and a refrigerant filling amount. 1 ... Compressor, 2 ... Four-way valve, 3 ... Outdoor heat exchanger, 4
... decompression capillary tube, 5 ... indoor heat exchanger, 6 ... accumulator, 7a-7g ... refrigerant pipe, 13 ... first bypass pipe, 14 ... second bypass pipe, 15 ... capillary pipe, 16a ... 1st refrigerant temperature detector, 16b ... 2nd refrigerant temperature detector, 17a ... 3rd refrigerant temperature detector, 17b ... 4th refrigerant temperature detector, 19 ... Arithmetic unit In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (4)

[Claims] 1. An air conditioner having a refrigerant circuit in which a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducing capillary tube, an indoor heat exchanger, and an accumulator are sequentially connected by a refrigerant pipe, and the discharge side of the compressor. A first bypass pipe having one end connected to the refrigerant pipe, a second bypass pipe having one end connected to the suction-side refrigerant pipe of the compressor and forming a heat exchange unit with the first bypass pipe, A first pipe that is installed on a capillary pipe connected between the other ends of the first and second bypass pipes and a refrigerant pipe that connects the discharge side of the compressor and a four-way valve to detect the refrigerant temperature of the refrigerant pipe. A temperature detector, a second refrigerant temperature detector installed on a refrigerant pipe connecting the accumulator and the four-way valve to detect the refrigerant temperature of the refrigerant pipe, and a heat exchange unit on the first bypass pipe. Check the saturated condensation temperature of the refrigerant Of the third refrigerant temperature detector, the fourth refrigerant temperature detector for detecting the saturated evaporation temperature of the refrigerant in the heat exchange section on the second bypass pipe, and the first to fourth refrigerant temperature detectors. A proper refrigerant filling amount detection device equipped with a calculation device for processing temperature information. 2. The proper refrigerant charging according to claim 1, wherein the heat exchange section is configured to exchange heat by closely adhering the first and second pipes for a predetermined length and fixing them. Quantity detection device. 3. The proper refrigerant charge amount detection 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. apparatus. 4. The arithmetic unit calculates the discharge superheat, which is the difference between the discharge temperature and the saturated condensing temperature, and the intake superheat, which is the difference between the suction temperature and the saturated evaporation temperature, as the criterion for determining the proper refrigerant amount. A proper refrigerant filling amount detection device according to claim 1, which is characterized.