JP2000161210A - Horizontal hermetic compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a danger of leakage and an electric shock by detecting two-layer separation installed in a lower part of an oiling part and a heater brought into close contact with a sealed casing. SOLUTION: A shaft 2 rotates by torque of a motor part 10 to move a piston 5 to compress a refrigerant in a compression chamber 7 formed of a sub-bearing 3, a bearing 4 and a cylinder 6. A temperature of a horizontal hermetic compressor rises by compression heat and heating of the motor part 10. The compressed refrigerant performs clooling by a refrigerating system, and returns to the compressor. The refrigerant and ester refrigerating machine oil are supplied to a machine part through an oiling device 8 for lubrication. The compressor becomes a high temperature by heating at refrigerant compressing time and heating of the motor part 10 by a repetition of operation, and the ester base refrigerating machine oil and the refrigerant are dissolved so as to eliminate two-layer separation. At compressore reducing time, a temperature/pressure in the compressor lower so as to deposit a refrigerant layer 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a horizontal hermetic compressor used for refrigerators, freezers and the like.

[0002]

2. Description of the Related Art In recent years, chlorofluorocarbon (hereinafter referred to as C)
Attention has been focused on environmental problems such as ozone layer depletion and global warming caused by the influence of FC. From this point of view, reducing the amount of CFC used as a refrigerant has become a very important theme. Conventionally, fully halogenated carbon compounds that have been used as CFCs contain at least one hydrogen.
Substitution is being attempted with halogenated carbon compounds containing more than one.

More specifically, dichlorodifluoromethane (hereinafter referred to as CFC-12) which is a typical refrigerant
Is an alternative substance to CFC, and various improvements have been made to replace it with 1,1,1,2-tetrofluoroethane (hereinafter referred to as HFC-134a) or the like which has little effect on ozone depletion.

[0004] For example, DuPo issued in October 1978
According to Research Disclosure of nt, HFC-134a is poorly compatible with any conventional oils, causes two-phase separation in all temperature ranges, and is only soluble in glycol-based oils only. However, subsequent studies have shown that it can also be dissolved in special ester-based oils. For example, in U.S. Pat. No. 4,851,144, a refrigerating machine oil in which an ester type and a glycol type are mixed is used as a refrigerant HFC.
-134a.

However, many ester refrigerating machine oils are hardly soluble in the refrigerant HFC-134a and cause two-layer separation, and the critical melting temperature is high. However, these ester refrigerating machine oils have higher reliability and lubricity than special ester refrigerating machine oils having a low critical solution temperature.

When the refrigerant and the refrigerating machine oil are separated into two layers, the refrigerating machine oil is located above the refrigerant because of its low specific gravity. Conversely, the refrigerant is located on the lower side.

[0007] It has also been found that the refrigerant HFC-134a contains a large number of hydrogen atoms, so that it is essentially easy to conduct electricity, and that the electrical insulation required for a horizontal hermetic compressor is very poor.

FIG. 4 is a sectional view of a conventional horizontal hermetic compressor. In FIG. 4, reference numeral 1 denotes a mechanical unit,
It comprises a sub bearing 3, a bearing 4, a piston 5 and a cylinder 6. The shaft 2, the sub bearing 3, the bearing 4, the piston 5,
The cylinder 6 forms a compression chamber 7. 8 is an oil supply pipe, 9 is a mixed oil of the refrigerant CFC-12 and the refrigerating machine oil, and the oil supply pipe 8 supplies the mixed oil 9 to the sliding surface. Reference numeral 10 denotes a motor unit. 11 is the mechanical unit 1 and the motor unit 1
0 is a metallic hermetic casing.

[0009]

In the horizontal hermetic compressor constructed as described above, the shaft 2 is rotated by the rotational force of the motor unit 10 to move the piston 5,
The refrigerant in the compression chamber 7 formed by the sub bearings 3, the bearing 4 and the cylinder 6 is compressed. The compressed refrigerant is cooled in the refrigeration system and returns to the compressor again.

A small compressor as shown in FIG.
In recent years, the horizontal type, that is, the mechanical unit 1 and the motor unit 10 for driving the mechanical unit are often installed horizontally for the purpose of saving space. That is, the refrigerant CFC-1
2 and refrigeration oil 9 are immersed in a mixed oil 9. Therefore, when HFC-134a having poor electrical insulation is used as it is in this compressor, refrigeration oil and refrigerant HFC-1 are used.
34a produce a two-layer separation. That is, since the oil has a low specific gravity, the oil forms the oil layer 12 on the upper side, and the refrigerant forms the refrigerant layer 13 on the lower side. Furthermore, since the refrigerant HFC-134a contains a large number of hydrogen atoms, it is essentially easy to flow electricity, and electricity flows from the motor unit 10 to the closed casing 11. For this reason, there is a possibility that a risk of electric leakage or electric shock may occur.

When the refrigerant HFC-134a and the refrigerating machine oil are separated into two layers before the compressor is started, the refrigerating machine oil and the refrigerant form layers in an upper layer and a lower layer, respectively. Initially, the mechanical part 1 of the compressor draws refrigerant from the refrigerant layer 13, and refrigerant lubrication occurs in the mechanical part 1. As the time elapses, the refrigerant in the compressor and the refrigerating machine oil increase in temperature of the compressor and the motor unit 1
Mixing is performed by the rotation of 0, and the refrigerant lubrication is gradually eliminated.

[0012] In a compressor for a refrigerator, the compressor normally performs an ON-OFF operation. Particularly, at a low outside air temperature, the OFF time is long and the temperature of the refrigerating machine oil is low, so that the two-layer operation is performed. Separation is likely to occur. At this time, when the starting is performed as described above, refrigerant lubrication occurs, and when this is repeated, wear occurs on the vane rollers, cylinders, and the like.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to prevent a danger of electric leakage or electric shock, and to eliminate two-layer separation and prevent refrigerant lubrication when starting a compressor.

[0014]

A horizontal hermetic compressor which solves the above-mentioned problems has a hermetic casing in which a refrigerant and a refrigerating machine oil are sealed, a mechanical part housed in the hermetic casing, and a motor for driving the mechanical part. A refueling device that conveys refrigerating machine oil to the mechanical unit, a heater that is in close contact with the closed casing, and a sensor that is installed below the refueling unit of the refueling device and that detects two-layer separation.

As specific sensors, an insulation resistance sensor for detecting the electric resistance between the refrigerant and the refrigerating machine oil, an infrared concentration sensor for detecting the infrared transmittance of the refrigerant and the refrigerating machine oil,
A viscosity sensor for detecting the viscosity of the refrigerant and the refrigerating machine oil is used.

Further, a refrigerating apparatus and a refrigerator provided with the above-mentioned horizontal hermetic compressor are also included in the gist of the present invention.

According to the present invention, the sensor detects the point at which the refrigerant and the refrigerating machine oil separate into two layers, and the heater heats the compressor to eliminate the two-layer separation between the refrigerant and the refrigerating machine oil. In addition, it is possible to prevent a risk of electric leakage and electric shock, and to prevent refrigerant lubrication at the time of starting the compressor.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A compressor according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 3 by using HFC-134a as a refrigerant and ester-based refrigerant oil having a high critical solution temperature as a refrigerant oil. However, the same components as those in the conventional example are denoted by the same reference numerals and description thereof is omitted.

The first embodiment will be described with reference to FIG.

Reference numeral 14 denotes a heater installed in the horizontal hermetic compressor, and reference numeral 15 denotes a controller for energizing the heater 14.

Reference numeral 16 denotes an insulation resistance sensor mounted below the oil supply pipe 8 of the compressor.

The operation of the horizontal hermetic compressor constructed as described above will be described.

The shaft 2 is rotated by the rotational force of the motor unit 10 to move the piston 5 to compress the refrigerant in the compression chamber 7 formed by the auxiliary bearing 3, bearing 4 and cylinder 6. The temperature of the horizontal hermetic compressor rises due to the compression heat and the heat generated by the motor section 12 at this time. On the other hand, the compressed refrigerant is cooled by the refrigeration system and returns to the compressor again. At this time, the refrigerant HFC-134a and the ester-based refrigerating machine oil are supplied to the machine unit through the oil supply device 8 for lubrication.

When the compressor is heated to a high temperature due to the heat generated during compression of the refrigerant or the heat generated by the motor unit 10 due to the repetition of the above operation, the ester-based refrigerating machine oil and the refrigerant HFC-13 are discharged.
4a gradually begins to dissolve, and finally the ester-based refrigerating machine oil and the refrigerant HFC-134a dissolve and the two-layer separation is eliminated. However, when the temperature of the compressor is lowered when the compressor is lowered, the refrigerant layer 13 is gradually deposited.

Next, the case where the refrigerant HFC-134a is dissolved in the refrigerating machine oil will be described.

The volume resistance, which is one of the indices indicating the insulating properties, is shown for each substance.

[0027]

[Table 1]

That is, the larger the value of volume resistance, the higher the electrical insulation. When a large amount of HFC-134a is dissolved in the refrigerating machine oil, the electrical insulation property is rapidly lowered.

According to the present invention, the insulation resistance sensor 16 eliminates the two-layer separation between the refrigerant oil and the refrigerant HFC-134a by utilizing the fact that the insulation resistance changes depending on the amount of the refrigerant dissolved in the refrigerant oil. Refrigerant 134a in refrigerating machine oil
Is to reduce the amount of dissolution. That is, when the motor of the horizontal hermetic compressor is stopped, the insulation resistance between the insulation resistance sensor 16 and the horizontal hermetic compressor is measured by the insulation resistance sensor 16, and when the insulation resistance becomes equal to or less than a predetermined value. The heater 1 is controlled by the heater energizing controller 15.
4 is energized to heat the refrigerator oil.

That is, when the insulation resistance of the horizontal hermetic compressor becomes equal to or less than a predetermined value by the heater 14 and the control device 15 for energization, the horizontal hermetic compressor is heated to heat the refrigerating machine oil and the refrigerant 134a. By raising the temperature, the two-layer separation between the refrigerating machine oil and the refrigerant 134a is eliminated, the refrigerant lubrication at the time of starting the compressor is eliminated, and the amount of the refrigerant 134a dissolved in the refrigerating machine oil decreases, and the oil level decreases. The electric insulation is improved, and no current flows in the casing, and the danger of electric leakage and electric shock does not occur.

The power consumption can be reduced by turning on and off the heater 14 by the insulation resistance sensor 16.

Next, a second embodiment will be described with reference to FIG.

Reference numeral 17 denotes an infrared concentration sensor mounted below the oil supply pipe 8 of the compressor. Reference numerals 18 and 19 denote a light emitting unit and a light receiving unit attached to the infrared concentration sensor. The infrared light emitted from the light emitting unit 18 is received by the light receiving unit 19, the absorption of each wavelength of the infrared light is calculated, and the refrigerant concentration in the refrigerator oil is calculated. Is determined.

The operation of the horizontal hermetic compressor constructed as described above will be described.

The shaft 2 is rotated by the rotational force of the motor unit 12 to move the piston 5 to compress the refrigerant in the compression chamber 7 formed by the auxiliary bearing 3, bearing 4 and cylinder 6. The temperature of the horizontal hermetic compressor rises due to the compression heat and the heat generated by the motor section 12 at this time. On the other hand, the compressed refrigerant is cooled by the refrigeration system and returns to the compressor again. At this time, the refrigerant HFC-134a and the refrigerating machine oil are supplied to the mechanical unit through the oil supply device 8 for lubrication.

By repeating the above operation, when the compressor becomes high temperature due to heat generation during compression of the refrigerant or heat generation of the motor part, the refrigerant oil and the refrigerant HFC-134a gradually begin to melt, and finally. Refrigeration oil and refrigerant HFC-134a
Dissolves and the two-layer separation is eliminated. However, when the compressor is stopped, the temperature and pressure in the compressor decrease, so that the refrigerant layer 13 is gradually deposited.

The present invention utilizes the fact that when the refrigerant 134a is dissolved in the refrigerating machine oil, the amount of infrared absorption varies depending on the amount of the refrigerant dissolved, thereby eliminating the two-layer separation between the refrigerating machine oil and the refrigerant 134a and the refrigerating machine oil. This is to reduce the amount of the refrigerant 134a dissolved therein. That is, when the motor of the horizontal hermetic compressor is stopped, the infrared concentration sensor 1
At 7, the refrigerant concentration in the refrigerating machine oil is measured, and when the refrigerant concentration becomes a predetermined value or more, the heater 14 is energized by the heater energizing control device 15 to heat the refrigerating machine oil.

That is, by heating the horizontal hermetic compressor when the refrigerant concentration of the hermetic hermetic compressor becomes equal to or higher than a predetermined value by the heater 15 and the control device 15 for electric current, the refrigerating machine oil and the refrigerant 134a are heated. By raising the temperature, the two-layer separation between the refrigerating machine oil and the refrigerant 134a is eliminated, the refrigerant lubrication at the time of starting the compressor is eliminated, and the amount of the refrigerant 134a dissolved in the refrigerating machine oil decreases, and the oil level decreases. The electric insulation is improved, and no current flows in the casing, and the danger of electric leakage and electric shock does not occur. Further, by turning on and off the heater 14 by the infrared refrigerant concentration sensor 17, the power consumption can be reduced.

When this infrared concentration sensor 17 is used, it is possible to determine the two-layer separation based on the infrared transmittance at a specific wavelength of the refrigerating machine oil or the refrigerant. Therefore, as compared with the insulation resistance sensor 16 according to the first embodiment, there is a feature that it is hardly affected by moisture or ionic substances which dissolve in the refrigerating machine oil and changes the electric resistance, thereby improving reliability during operation.

Next, a third embodiment will be described with reference to FIG.

Reference numeral 20 denotes a viscosity sensor mounted below the oil supply pipe 8 of the compressor.

Numerals 21 and 22 denote a thin tube and a temperature sensor attached to the viscosity sensor 20, which detect the time during which a fixed volume of fluid flows through the thin tube 21 and detect the oil temperature of the refrigerating machine oil to correct the viscosity.

Next, the operation will be described.

The shaft 2 is rotated by the rotational force of the motor section 12 to move the piston 5 to compress the refrigerant in the compression chamber 7 formed by the sub-bearing 3, bearing 4 and cylinder 6. The temperature of the horizontal hermetic compressor rises due to the compression heat and the heat generated by the motor section 12 at this time. On the other hand, the compressed refrigerant is cooled by the refrigeration system and returns to the compressor again. At this time, a mixed liquid of the refrigerant HFC-134a and the refrigerating machine oil is supplied to the mechanical unit through the oil supply device 8 for lubrication.

By repeating the above operation, when the compressor becomes high temperature due to heat generated during compression of the refrigerant or heat generated by the motor portion, the refrigerant oil and the refrigerant HFC-134a gradually begin to melt, and finally the refrigerant oil And refrigerant HFC-134a
Dissolves and the two-layer separation is eliminated. However, when the temperature and pressure in the compressor decrease when the compressor is lowered, the refrigerant layer is gradually deposited.

The present invention utilizes the fact that when the refrigerant 134a is dissolved in the refrigerating machine oil, the viscosity of the refrigerating machine oil and the refrigerant are reduced because the viscosity of the refrigerating machine oil and the refrigerant 13a are reduced.
This is to eliminate the two-layer separation of 4a and reduce the amount of refrigerant 134a dissolved in the refrigerating machine oil. That is,
When the motor of the horizontal hermetic compressor is stopped, the viscosity of the refrigerating machine oil is measured by the viscosity sensor 20 and when the viscosity becomes a predetermined value or less, the heater 15 is energized by the heater energizing controller 16 to heat the refrigerating machine oil. I do.

That is, when the viscosity of the refrigerating machine oil of the horizontal hermetic compressor becomes equal to or less than a predetermined value by the heater 15 and the control device 16 for energization, the refrigerating machine oil and the refrigerant 134a are heated by heating the horizontal hermetic compressor. By heating and raising the temperature, the two-layer separation of the refrigerating machine oil and the refrigerant 134a is eliminated, the refrigerant lubrication at the time of starting the compressor is eliminated, and the amount of the refrigerant 134a dissolved in the refrigerating machine oil is reduced and the oil level is reduced. As a result, the electric insulation is improved, and no current flows in the casing, and the danger of electric leakage and electric shock does not occur. Also heater 1
The power consumption can be reduced by turning ON / OFF of 4 by the viscosity sensor 18.

When this viscosity sensor 20 is used,
Viscosity is detected using inherent shear stress, which is a physical characteristic of refrigerating machine oil or refrigerant, to determine two-layer separation. Further, the viscosity, which is a physical property, is hardly affected by deterioration of the refrigerating machine oil or the refrigerant. Therefore, as compared with the infrared sensor 17 of the second embodiment, the level of detection is kept constant over a long period, and the reliability during operation is improved. Also, compared to the insulation resistance sensor 16 of the first embodiment, the water and ionic substances dissolved in the refrigerating machine oil do not affect the viscosity. That is, it goes without saying that the reliability during operation is higher than that of the insulation resistance sensor 16.

Regarding the first to third embodiments,
The refrigerant HFC-134a and the ester-based refrigerating machine oil have been described. ○ Refrigerant HFC152a and alkylbenzene-based refrigerating machine oil ○ Three kinds of refrigerant mixture (HCFC22, HFC152a and H
Refrigerant oil mixed with CFC124 or CFC114) and alkylbenzene-based refrigerating machine oil.

[0050]

The refrigerant and the refrigerating machine oil undergo two-layer separation, and the two-layer separation curve is upwardly convex. The hermetically sealed casing enclosing the refrigerant and the refrigerating machine oil, the mechanical part housed in the hermetically sealed casing, and A motor unit that drives a mechanical unit, an oil supply device that conveys refrigerating machine oil to the mechanical unit, a heater that is in close contact with the closed casing, and a sensor that detects two-layer separation installed below the oil supply unit of the oil supply device. Consisting of

Some sensors use an insulation resistance sensor for detecting the electrical resistance between the refrigerant and the refrigerating machine oil.

Further, as the sensor, an infrared concentration sensor for detecting the infrared transmittance of the refrigerant and the refrigerating machine oil is used.

Further, a viscosity sensor for detecting the viscosity of the refrigerant and the refrigerating machine oil is used as the sensor.

Thus, the following effects can be obtained.

A When the sensor detects the point at which the refrigerant and the refrigerating machine oil separate into two layers when the compressor is stopped, the heater heats the compressor, cancels the two-layer separation between the refrigerant and the refrigerating machine oil, and operates when the compressor starts. Eliminate refrigerant lubrication.

B. Heating by the heater reduces the amount of the refrigerant 134a dissolved in the refrigerating machine oil and lowers the oil level, thereby improving the electrical insulation and preventing the current from flowing in the casing, thereby reducing the risk of electric leakage and electric shock. No longer occurs.

[Brief description of the drawings]

FIG. 1 is a sectional view of a compressor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a compressor according to another embodiment of the present invention.

FIG. 3 is a sectional view of a compressor according to another embodiment of the present invention.

FIG. 4 is a sectional view of a conventional compressor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mechanical part 12 Motor part 14 Heater 15 Control device for electric conduction 16 Insulation resistance sensor 17 Infrared density sensor 20 Viscosity sensor

Claims (6)

[Claims] A closed casing enclosing an HFC-based refrigerant and an ester-based refrigerating machine oil, a mechanical unit housed in the closed casing, and a motor unit for driving the mechanical unit;
An oil supply device that conveys refrigerating machine oil to the mechanical unit, a heater that is in close contact with the closed casing, that the HFC-based refrigerant sealed in the closed casing is separated into a lower layer, and that the ester-based refrigerating machine oil is separated into an upper layer. A horizontal hermetic compressor comprising a sensor that detects and energizes the heater. 2. The horizontal hermetic compressor according to claim 1, wherein the sensor is an insulation resistance sensor for detecting electric resistance between the refrigerant and the refrigerating machine oil. 3. The horizontal hermetic compressor according to claim 1, wherein the sensor is an infrared concentration sensor for detecting the infrared transmittance of the refrigerant and the refrigerating machine oil. 4. The horizontal hermetic compressor according to claim 1, wherein the sensor is a viscosity sensor for detecting the viscosity of the refrigerant and the refrigerating machine oil. 5. A refrigerating apparatus comprising the horizontal hermetic compressor according to claim 1. 6. A refrigerator comprising the horizontal hermetic compressor according to claim 1.