JPH0979144A - Internal drying method of hermetic compressor - Google Patents

Abstract

(57) Abstract: The time required for the temperature rise of the compressor is shortened and the internal drying of the compressor is promoted without supplying a large current to the coil of the stator of the compressor. An internal drying method for a hermetic compressor includes a drying step A for removing water inside the compressor, and a lubricating oil enclosing step B for enclosing lubricating oil in the compressor thereafter. The drying step A includes a heating step 1 in which a high-frequency magnetic field is externally applied to the compressor to heat it and at the same time, high-temperature and high-pressure dry air is ventilated inside the compressor to raise the temperature of the compressor. There is. Further, the drying step A has a heat retention / exhaust step 2 in which, after the temperature increase step 1, the stator inside the compressor is energized and warmed while the compressor is evacuated to vacuum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor internal drying method for removing moisture in a compressor in a process of manufacturing a hermetic compressor, and more particularly to a hermetic compressor for heating and vacuum exhausting the compressor. Type compressor internal drying method.

[0002]

2. Description of the Related Art FIG. 6 shows a general hermetic compressor 10 having a compressor body 11 and an accumulator 12. The main body 11 of the compressor 10 includes a case 13 including a main case 13a and an upper case 13b.
It has. Inside the case 13, the compression unit 14
And a crankshaft 15 penetrating the compression portion 14 are arranged. A rotor 16 of an electric motor is fixed to the crankshaft 15, and a stator 17 having a coil is arranged so as to surround the rotor 16. Further, a discharge pipe 20 and a power supply terminal 21 are arranged above the upper case 13b. On the other hand, accumulator 12
A suction pipe 18 is provided on the upper part of the accumulator 1
2 In the lower part, the compression part 14 of the main body 11 and the accumulator 1
A pair of connecting pipes 19 that communicate with the inside of the 2 are provided.

Here, in the hermetic compressor as exemplified above, when water is present inside the compressor, corrosion of the metallic material of the compressor and generation of sludge, copper plating phenomenon,
Alternatively, a problem such as deterioration of a chemical material such as an insulating material may occur. Therefore, at the compressor manufacturing stage,
It is necessary to sufficiently remove the water inside the compressor. Further, particularly in recent years, switching to a new refrigerant has been promoted due to the ozone layer depletion problem of the CFC refrigerant, and the lubricating oil for this new refrigerant is generally highly hygroscopic. Therefore, in order to prevent deterioration of the lubricating oil due to moisture absorption, the necessity of removing water from the inside of the compressor is increasing.

Therefore, various methods of internally drying a compressor have been proposed so far in order to remove moisture inside the hermetic compressor. An example of such a conventional compressor internal drying method is shown in FIGS. First, the furnace heating / hot air ventilation method is shown in FIG. This method
The compressor 10 is externally heated by the heating furnace 70, and hot air and high pressure dry air is sent to the suction pipe 18 of the compressor 10 through the ventilation pipe 44 by the hot air ventilation device 40 having the blower 42 and the heating wire 43. It is discharged from the discharge pipe 20.

Next, as shown in FIG. 8, the furnace heating /
It is a vacuum exhaust method. In this method, the compressor 10 is heated by a heating furnace 7
It is heated from the outside by 0 and the vacuum pump 60
The air inside the compressor 10 is evacuated from the suction pipe 18 and the discharge pipe 20 through the exhaust pipe 61.

FIG. 9 shows a stator energization heating / vacuum exhaust method. In this method, the air inside the compressor 10 is evacuated from the suction pipe 18 and the discharge pipe 20 through the exhaust pipe 61 by the vacuum pump 60, and the power supply terminal 21 of the compressor 10 is connected to the electric cable 81.
A DC power supply 80 is connected, and the DC power supply 80 energizes and heats the coil of the stator 17.

[0007]

However, these internal drying methods for hermetic compressors have the following problems. That is, in any of the above methods, the temperature rise of each part of the compressor 10 is slow, so that the drying operation takes a long time. Further, in the method of combining the vacuum exhaust shown in FIGS. 8 and 9, since the vacuum exhaust is preferentially performed over the temperature increase of each part of the compressor 10 (see FIG. 10), the temperature decrease due to the vacuum exhaust is performed. Causes the water inside the compressor 10 to remain,
Inadequate water removal cannot be performed. In particular, the compressor 1
In the case of 0, the heat capacity of the stator 17 portion is large, so such a problem is likely to occur around the stator 17.

Further, in the method of electrically heating the stator 17 shown in FIG. 9, energization control is difficult, and a large current (lock current) is passed through the coil of the stator 17 in order to sufficiently heat each part of the compressor 10. Stator 1
There is a risk of damaging the coil of No. 7. In particular, when the 10 electric motors of the compressor are DC motors, the rotor 1
Since the magnet of No. 6 may be demagnetized, it is not preferable to apply a large current to the coil of the stator 17.

The present invention has been made in consideration of the above points, and in the internal drying method for a hermetic compressor, the temperature of the compressor can be increased without causing a large current to flow through the coil of the stator of the compressor. The purpose is to reduce the time required.

[0010]

A first means is an internal drying method for a hermetic compressor, wherein a high-frequency magnetic field is applied to the hermetic compressor from the outside to heat the hermetic compressor to raise the temperature of the compressor. It is characterized by having a drying step having a warming step. According to the first means, the temperature of the compressor can be raised in a short time by the temperature raising step without flowing a large current through the coil of the stator of the compressor.

The second means is that, in the temperature raising step of the drying step of the first means, at the same time, a high temperature /
It is characterized by ventilating high-pressure dry air. According to the second means, the temperature of the compressor can be raised in the temperature raising step in a shorter time than that of the first means.

A third means is the heat insulating method according to the first or second means, wherein in the drying step, after the temperature raising step, the stator of the compressor is energized and kept warm while the compressor is evacuated. -Characterized by having an exhaust process.
According to the third means, after the temperature of the compressor is raised by the temperature raising process of the first or second means,
In the exhaust step, by keeping the stator of the compressor electrically heated, it is possible to perform internal drying by vacuum exhaust of the compressor while supplying heat to the stator and its coil. Therefore, the internal drying of the compressor can be promoted.

A fourth means is the above-mentioned third means,
After the drying step, a lubricating oil enclosing step of enclosing lubricating oil inside the compressor is provided. According to the fourth means, in the lubricating oil filling step, the third
Since the lubricating oil can be enclosed in the compressor that has been sufficiently dried by the drying step of the means described above, the moisture absorption of the lubricating oil can be effectively prevented.

[0014]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 to 4 are views showing an embodiment of an internal drying method for a hermetic compressor according to the present invention. In the embodiment shown in FIGS. 2 to 4,
The same components as those of the conventional example shown in FIGS. 6 to 9 are designated by the same reference numerals for description.

As shown in FIG. 1, the internal drying method of the hermetic compressor according to the present embodiment includes a drying step A and a drying step A.
And a lubricating oil filling step B after the above. First, the drying step A will be described with reference to FIGS. 1 to 3. As shown in FIG. 1, the drying step A has a temperature raising step 1 by a combination of high frequency induction heating and hot air ventilation, and a subsequent heat retention / exhaust step 2 by a combination of stator energization heat retention and vacuum exhaust. ing.

First, in the temperature raising step 1, as shown in FIG. 2, the hermetic compressor 10 is heated by applying a high frequency magnetic field from the outside (high frequency induction heating), and at the same time, the compressor 10 is heated.
The temperature of each part of the compressor 10 is raised by ventilating high-temperature, high-pressure dry air (hot air ventilating) inside. Of these, high frequency induction heating is performed by a high frequency induction heating device 30 including a horseshoe-shaped high frequency coil 31 and a high frequency power supply 32. That is, by applying a high-frequency magnetic field to the compressor 10 from the high-frequency coil 31 arranged so as to surround the periphery, the case 13 of the compressor 10 and the iron plate of the stator 17 (see FIG. 6) cause internal eddy currents. Is induction heated.

The hot air ventilation is performed by a hot air ventilation device 40 connected to the suction pipe 18 of the compressor 10 as shown in FIG. 2 (a). This hot air ventilation device 40 is
It has a blower 42 and an electric heating wire 43 housed in the case 40, and sends high-temperature and high-pressure dry air to the suction pipe 18 of the compressor 10 through a connecting pipe 44. Then, the high-temperature, high-pressure dry air sent from the suction pipe 18 by the hot air ventilation device 40 passes through the compressor 10 and is discharged from the discharge pipe 20, whereby the compressor 10
Are heated. Then, when the temperature of the surface of the compressor 10 rises to a predetermined value, high frequency induction heating and hot air ventilation are terminated.

Next, in the heat retention / exhaust step 2, FIG.
As shown in FIG. 5, the stator 17 of the compressor 10 is kept warm by electricity, and at the same time, the compressor 10 is evacuated to remove water inside the compressor 10.
Of these, the stator energization heat retention is performed by the energization heat retention device 50 connected to the power supply terminal 21 of the compressor 10 by the electric cable 55. The energization heat retention device 50 includes a circuit switching control unit 51 to which an electric cable 55 is connected, a DC power source 52 and a resistance meter 53 connected to the control unit 51.
And a personal computer 54 for operating and monitoring the operation of the device. Then, from the energization heat insulation device 50 to the electric cable 55 and the power supply terminal 2 of the compressor 10.
By supplying a heat retaining current to the coil of the stator 17 via 1, the energization heat retaining of the stator 17 is performed. The vacuum exhaust is performed by using a vacuum pump 60 to exhaust the air inside the compressor 10 from the suction pipe 18 and the discharge pipe 20 through an exhaust pipe 61. In particular, since it is highly possible that a small amount of water adheres to the coils of the stator 17, the combination of the heat insulation and the vacuum exhaust of the compressor 10 is effective for the internal drying of the compressor 10.

Next, referring to FIGS. 1 and 4, the lubricating oil filling step B performed after the drying step A will be described.
As shown in FIG. 1, the lubricating oil filling step B includes a lubricating oil injection step 3, a performance test step 4, a suction / discharge port rubber cap attaching step 5, a vacuuming step 6, and an N ₂ gas filling step 7 that are sequentially performed. have. Of these, lubricating oil injection step 3
Is a step of injecting lubricating oil into the interior of the compressor 10 from which the internal moisture has been removed by the drying step A. Further, as shown in FIG. 4, the suction / discharge port rubber cap attaching step 5 is a step of inserting and sealing the rubber caps 8 into the openings of the tip ends of the suction pipe 18 and the discharge pipe 20 (see FIG. 4). Is illustrated only for the discharge pipe 20 for the sake of convenience). Then, in the evacuation step 6 and the N ₂ gas charging step 7, a needle 9 is penetrated through the rubber cap 8, and the inside of the compressor 10 is evacuated and the N ₂ gas is injected through the needle 9, respectively. When the needle 9 is pulled out from the rubber cap 8 after N ₂ gas is filled, the needle hole of the rubber cap 8 is automatically closed by the elasticity of rubber or the like.

As shown in FIG. 1, the compressor 10 which has undergone the drying step A and the lubricating oil enclosing step B as described above is
It will be shipped as a finished product.

Next, the operation of the present embodiment having such a configuration will be described. According to this embodiment, in the heating step 1 of the drying step A, a high-frequency magnetic field is applied to the compressor 10 from the outside to heat (high-frequency induction heating), and at the same time, high-temperature and high-pressure dry air is introduced into the compressor 10. Since the temperature of the compressor 10 is raised by ventilating (hot air ventilation) the stator 1 of the compressor 10.
The temperature of each part of the compressor 10 can be raised in an extremely short time without passing a large current through the coil of No. 7. Therefore, the drying time inside the compressor 10 can be shortened, and the coil of the stator 17 may be damaged,
It does not cause demagnetization of the magnet of the rotor 16 (see FIG. 6).

In the heat retention / exhaust step 2 of the drying step A, the stator 17 is energized and kept warm to supply heat to the stator 17 and its coils while the compressor 1 is being reheated.
Internal drying can be performed by evacuating to zero. Therefore, it is possible to promote the internal drying of the compressor and reduce the water content remaining inside the compressor 10. In particular, since it is highly possible that a small amount of water adheres to the coils of the stator 17, the combination of the heat insulation and the vacuum exhaust of the compressor 10 is effective for the internal drying of the compressor 10. In addition, since it is not necessary to flow a large current as in the conventional energization and heating for energizing and keeping the temperature of the stator 17, the coil of the stator 17 is damaged or the magnet of the rotor 16 (see FIG. 6) is demagnetized. There is nothing to do.

Further, in the lubricating oil enclosing step B, the lubricating oil can be enclosed inside the compressor 10 that has been sufficiently dried in the drying step A, so that the absorption of the lubricating oil can be effectively prevented. Therefore, it is possible to prevent deterioration of the performance of the lubricating oil and ensure stable operation of the compressor 10.

Experimental Results Next, the experimental results of the internal drying method for the hermetic compressor according to the present invention will be described with reference to FIG. In this experiment, the internal drying operation of the hermetic compressor is actually performed by the method of the above-described embodiment, and each part of the compressor 10 (the outside of the case 13 of the compressor body (work) 11 and the coil of the stator 17) is elapsed at each elapsed time. (Internal coil)) temperature and compressor 1
The degree of vacuum in 0 was measured. As a result, the time required to raise the temperature of each part of the compressor 10 has been significantly shortened from about 20 to 40 minutes (see FIG. 10) in the related art to about 10 minutes. In particular, the time required to raise the temperature of the stator 17 portion, which conventionally required a long time of about 40 minutes, is remarkably shortened. Further, according to the method of the present invention, unlike the conventional method,
It can be seen that the temperature of each part of the compressor 10 is raised prior to the vacuum exhaust.

Further, according to the method of the present invention, it has been found that the residual water content inside the compressor 10 when the drying operation is performed for 70 minutes by the conventional method can be reached in about 30 minutes, which is less than half of the residual water content. . This proves that the method of the present invention is extremely effective in shortening the compressor drying time and promoting the internal drying of the compressor.

[0026]

According to the first aspect of the invention, the temperature of the compressor can be raised in a short time by the temperature raising step without causing a large current to flow through the coil of the stator of the compressor. Therefore, the drying time of the compressor can be shortened, the coil of the stator is not damaged, and the demagnetization of the rotor magnet is not caused.

According to the invention described in claim 2, in the invention described in claim 1, the temperature of the compressor is raised in a shorter time by the temperature raising step, and the drying time of the compressor can be further shortened. it can.

According to the third aspect of the present invention, after the temperature of the compressor is raised by the temperature raising step of the first or second aspect of the invention, the stator of the compressor is energized and kept warm in the heat retaining / exhausting step. As a result, it is possible to perform internal drying by evacuation of the compressor while supplying heat to the stator and its coil. Therefore, it is possible to promote the internal drying of the compressor and reduce the water content remaining inside the compressor. In addition, since it is not necessary to pass a large current as in the conventional energizing and heating for energizing and keeping the temperature of the stator, neither damage to the coil of the stator nor demagnetization of the rotor magnet is caused.

According to the invention described in claim 4, in the lubricating oil filling step, since the lubricating oil can be filled inside the compressor sufficiently dried by the drying step of the invention described in claim 3, the lubricating oil absorbs moisture. Can be effectively prevented. Therefore, it is possible to prevent the performance of the lubricating oil from deteriorating and ensure stable operation of the compressor.

[Brief description of drawings]

FIG. 1 is a process diagram showing an embodiment of an internal drying method for a hermetic compressor according to the present invention.

FIG. 2 is a schematic diagram showing a temperature raising step of the internal drying method shown in FIG.

FIG. 3 is a schematic diagram showing a heat retention / exhaust step of the internal drying method shown in FIG.

FIG. 4 is a rubber cap attaching step, a vacuuming step, and N ₂ in the lubricating oil injecting step of the internal drying method shown in FIG.
The principal part perspective view which shows a gas charging process.

FIG. 5 is a graph showing an experimental result of a drying operation by the internal drying method of the hermetic compressor according to the present invention.

FIG. 6 is a vertical sectional view showing an example of a conventional hermetic compressor.

FIG. 7: Internal drying method of a conventional hermetic compressor (furnace heating /
The schematic diagram which shows the hot-air ventilation method.

FIG. 8: Internal drying method for a conventional hermetic compressor (furnace heating /
Schematic diagram showing a vacuum exhaust method).

FIG. 9 is a schematic diagram showing an internal drying method (stator electrification heating / vacuum exhaust method) of a conventional hermetic compressor.

FIG. 10 is a graph showing an experimental result of a drying operation by an internal drying method of a conventional hermetic compressor.

[Explanation of symbols]

 A Drying process B Lubricating oil encapsulation process 1 Temperature raising process 2 Heat retention / exhaust process 10 Compressor 17 Stator 30 High frequency induction heating device 40 Hot air ventilation device 50 Electric heat retention device 60 Vacuum pump

Claims (4)

[Claims] 1. An inside of a hermetic compressor, comprising a drying step including a temperature raising step of raising the temperature of the hermetic compressor by applying a high frequency magnetic field from the outside to heat the hermetic compressor. Drying method. 2. The internal drying method for a hermetic compressor according to claim 1, wherein in the temperature raising step of the drying step, high-temperature and high-pressure dry air is simultaneously ventilated inside the compressor. 3. The drying step comprises a heat retention / exhaust step of performing vacuum exhaust of the compressor while keeping the stator of the compressor electrically energized after the temperature raising step. 2. The internal drying method for a hermetic compressor according to 2. 4. The internal drying method for a hermetic compressor according to claim 3, further comprising a lubricating oil enclosing step of enclosing lubricating oil in the compressor after the drying step.