JPH04179876A - Sealed type compressor - Google Patents

Abstract

PURPOSE:To prevent coolant lubrication at the time of starting by providing a mechanical part, a motor part, an oil supplying device, and heater in a sealed type caing wherein coolant and refregerator oil are sealed, and also providing a sensor on a lower part of an oil supplying part of the oil supply device for sensing separation of oil and coolant. CONSTITUTION:When a motor 10 of a sealed type compressor is stopped, an insulative resistance between an insulative resistance sensor 16 and the sealed type compressor is measured. When the insulative compresse is a specified value or lower, electric current is supplied to a heater 14 by means of an electric supply control device 15 for heater to heat refregerator oil and coolant. Separation of the refregerator oil and the coolant is prevented by increasing a temperature and coolant lubrication at the starting time of the compressor is avoided. Electric insulativeness is improved because a solution ratio of the coolant into the refregerator oil is decreased and an oil level is lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a hermetic compressor used in refrigerators, freezers, etc.

Prior art In recent years, chlorofluorocarbons (hereinafter referred to as CFCs)
Environmental problems such as ozone layer depletion and global warming due to the effects of environmental pollution are attracting attention. From this perspective, reducing the amount of CFC refrigerant used has become an extremely important theme. The fully halogenated carbon compounds conventionally used as CFCs are being replaced by halogenated carbon compounds containing at least one hydrogen.

More specifically, dichlorodifluoromethane (hereinafter referred to as CFC-12), a typical refrigerant, is an alternative substance to CFC, and has 1.
1.1.2-tetrafluoroethane (hereinafter referred to as RFC-13
4a), etc., various improvement efforts are being made to replace them.

For example, DuPont's Re, published in October 1978.
According to the description of s@arch DLsclogure,
RFC-134a has poor compatibility with any conventional oil, causing two-layer separation in all temperature ranges, and is only soluble in glycol-based oils. However, subsequent research has revealed that it is also soluble in special ester oils. for example,
It is shown in US Pat. No. 4,851,144 that a mixed ester-based and glycol-based refrigerating machine oil dissolves in the refrigerant RFC-134a.

However, many ester-based refrigeration oils use refrigerant RFC-1
It was difficult to dissolve with 34a, resulting in two-layer separation, and the critical dissolution temperature was high. However, these ester-based refrigeration oils have higher reliability and lubricity than special ester-based refrigeration oils that have a low critical melting temperature.

When a two-layer separation occurs between the refrigerant and the refrigerating machine oil, the refrigerating machine oil is located above the refrigerant because of its light specific gravity. On the contrary, the refrigerant is located at the bottom.

It has also been found that since the refrigerant RFC-134a contains a large number of hydrogen atoms, it is inherently easy to conduct electricity, and the electrical insulation required for hermetic compressors is extremely poor.

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

In Fig. 4, reference numeral 1 indicates a mechanical part, including a shaft 2°, a secondary bearing 3. Bearing 4. It consists of a piston 6 and a cylinder 6. The shaft 2. Secondary bearing 3. Bearing 4. The piston 6 and cylinder 6 form a compression chamber 7. 8 is a fuel supply pipe; 9
is a mixed oil of cold tIXCFC-12 and refrigerating machine oil, and the oil supply pipe 8 supplies the mixed oil 9 to the sliding surface. 1o is a motor section. Reference numeral 11 denotes a metal sealed casing that houses the mechanical section 1 and motor section 1o.

Problems to be Solved by the Invention In the hermetic compressor configured as described above, the shaft 2 is rotated by the rotational force of the motor section 1o, moves the piston 6, and moves the sub-bearing 3. The refrigerant in the compression chamber T formed by the bearing 4 and the cylinder 6 is compressed. The compressed refrigerant is cooled by a freezing system and then returned to the compressor.

Furthermore, in recent years, small compressors such as the one shown in the figure have become more and more horizontal in order to save space, that is, the mechanical part 1 and the motor part 1o that drives the mechanical part are often installed horizontally. . That is, it has a structure in which it is immersed in a mixed oil 9 of refrigerant CFC-12 and refrigerating machine oil. Therefore, if HFC-134a, which has poor electrical insulation properties, is used as is in this compressor, two-layer separation will occur between the refrigerating machine oil and the refrigerant RFC-134a. Since TB oil has a light specific gravity, there is an oil layer on the upper side.
2, and conversely, the refrigerant forms a refrigerant layer 12 on the lower side. Furthermore, since the refrigerant HFC-1s4a contains a large number of hydrogen atoms, it is essentially easy to conduct electricity, and electricity flows from the motor section 1o to the sealed casing 11. Therefore, there was a possibility that there would be a risk of electrical leakage or electric shock.

In addition, if the refrigerant RFC-134a and the refrigerating machine oil are separated into two layers before starting the compressor, the refrigerating machine oil forms an upper layer and the refrigerant forms a lower layer.
At the initial stage of startup, the mechanical section 1 of the compressor sucks refrigerant from the refrigerant layer 13, and refrigerant lubrication occurs within the mechanical section 1. As time passes, the refrigerant and refrigerating machine oil in the compressor increase in temperature during compression and are mixed by the rotation of the motor section 10, and refrigerant lubrication is gradually eliminated.

Compressors for refrigerators are usually 0N-OF.
OF is being operated, especially when the outside temperature is low.
Since the F time is long and the temperature of the refrigerating machine oil is low, two-layer separation is likely to occur.

At this time, as mentioned above, when startup is applied, refrigerant lubrication occurs,
When this is repeated, the vane roller.

Wear occurs in cylinders, etc.

Therefore, it is an object of the present invention to prevent the risk of electrical leakage or electric shock, and also to eliminate the two-layer separation and prevent refrigerant lubrication when starting up the compressor.

Means for Solving the Problems In order to solve the above-mentioned order, the compressor of the present invention includes a sealed casing in which refrigerant and refrigeration oil are sealed, a mechanical part housed in the sealed casing, and a mechanical part that drives the mechanical part. A motor section, an oil supply device that conveys refrigerating machine oil to the mechanical section, a heater that is in close contact with the sealed casing, and a sensor that detects two-layer separation that is installed below the oil supply section of the oil supply device. .

Furthermore, an insulation resistance sensor is used as a sensor to detect the electrical resistance of the refrigerant and the refrigerating machine oil.

Furthermore, an infrared concentration sensor that detects the transmittance of infrared rays of the refrigerant and refrigerating machine oil is used as a sensor.

In addition, a viscosity sensor is used as a sensor to detect the viscosity of the refrigerant and refrigerating machine oil.

According to the above-described configuration, the sensor detects the point at which the refrigerant and refrigerating machine oil separate into two layers, and the heater heats the compressor, thereby eliminating the two-layer separation between the refrigerant and refrigerating machine oil. This prevents the risk of electrical leakage or electric shock, and also prevents refrigerant lubrication when starting the compressor.

Example Below, the refrigerant is subjected to RFC for a compressor according to an example of the present invention.
-134a, the refrigerating machine oil is an ester-based refrigerating machine oil with a high critical melting temperature, and will be explained with reference to FIGS. 1 to 3, but the same parts as in the conventional example will be given the same numbers and the explanation will be omitted.

A first embodiment will be described with reference to FIG.

14 is a heater installed in the hermetic compressor, and 16 is a power supply control device for the heater 14.

Further, 16 is an insulation resistance sensor attached below the oil supply pipe 8 of the compressor.

The operation of the hermetic compressor configured as above will be explained.

The shaft 2 is rotated by the rotational force of the motor part 1o, moves the piston 6, and compresses the refrigerant in the compression chamber 7 formed by the sub-bearing 3, the bearing 4, and the cylinder 6. At this time, the temperature of the hermetic compressor increases due to the heat of compression and the heat generated by the motor section 12. Meanwhile, the compressed refrigerant is cooled in the refrigeration system and returned to the compressor. At this time, refrigerant I'1FC-134a and ester-based refrigerating machine oil are supplied to the mechanical part through the oil supply device 8 for lubrication.

Contrary to the above operation, when the compressor becomes high temperature due to heat generation during refrigerant compression or heat generation in the motor part 1o, the ester-based refrigerating machine oil and the refrigerant RFC-134a gradually begin to dissolve. Ester-based refrigeration oil and refrigerant RF are used.
C-134a dissolves and the two-layer separation is eliminated. but,
When the compressor is lowered, the temperature and pressure inside the compressor decreases, so that the refrigerant layer 13 gradually precipitates.

Next, a case where refrigerant RFC-134a is dissolved in refrigerating machine oil will be explained.

The volume resistance value, which is one of the indicators of insulation properties, is shown for each substance.

HFC134a 10 Ω inverted glycol-based refrigeration oil 1010 Ω61CFC-1210 Ω inverted conventional refrigeration oil 10 Ω country ester-based refrigeration oil 10 Ω (according to in-house measurement results) Regarding the insulation properties of the tabs, the higher the volume resistance, the better the insulation. expensive. If a large amount of RFC-134a is dissolved in the refrigerating machine oil, the electrical insulation properties will drop sharply, so it is desirable to reduce the amount dissolved in the refrigerating machine oil and also to lower the oil level.

In the present invention, the insulation resistance sensor 16 eliminates the two-layer separation between the refrigeration oil and the refrigerant RFC-134m by utilizing the fact that the insulation resistance changes depending on the amount of refrigerant dissolved in the refrigeration oil. This is to reduce the amount of refrigerant 134a dissolved in the refrigerant 134a.

That is, when the motor of the hermetic compressor is stopped, the insulation resistance sensor 16 measures the insulation resistance between the insulation resistance sensor 16 and the hermetic compressor, and when the insulation resistance falls below a predetermined value, the heater is turned off. The energization control device 16 energizes the heater 14 to heat the refrigerating machine oil.

By heating the hermetic compressor when the insulation resistance of the hermetic compressor falls below a predetermined value using the heater 14 and the energization control device 16, the refrigerating machine oil and the refrigerant 134a are heated.
By heating and raising the temperature, refrigerating machine oil and refrigerant 1
34a is eliminated, refrigerant lubrication at the time of compressor startup is eliminated, and the amount of refrigerant 134a dissolved in the refrigerating machine oil is reduced, and the oil level is lowered, which improves electrical insulation and allows current to flow inside the casing. There is no risk of current leakage or electric shock.

Also, connect the heater 14 to the insulation resistance sensor 16.
Power consumption can be reduced by switching to FF.

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

17 is an infrared concentration sensor attached below the oil supply pipe 8 of the compressor. Reference numerals 18 and 19 denote a light emitting part and a light receiving part attached to the infrared concentration sensor.The light receiving part 19 receives the infrared rays emitted by the light emitting part 18, calculates the absorption of each wavelength of the infrared rays, and calculates the absorption of each wavelength of the infrared rays. Determine refrigerant concentration.

The operation of the hermetic compressor configured as above will be explained.

The shaft 2 is rotated by the rotational force of the motor section 12, moves the piston 6, and compresses the refrigerant in the compression chamber γ formed by the sub-bearing 3, the bearing 4, and the cylinder 6. At this time, the temperature of the hermetic compressor increases due to the heat of compression and the heat generated by the motor section 12. Meanwhile, the compressed refrigerant is cooled in the refrigeration system and returned to the compressor. At this time, refrigerant RFC-134a and refrigerating machine oil are supplied to the mechanical part through the oil supply device 8 for lubrication.

As a result of the above operation, when the compressor becomes high temperature due to heat generated during refrigerant compression or heat generated by the motor, the refrigerating machine oil and refrigerant RFC-134a begin to gradually dissolve and eventually freeze. Machine oil and refrigerant RFC-134a are dissolved and the two-layer separation is eliminated.

However, the temperature inside the compressor when the compressor is stopped.

As the pressure decreases, the refrigerant layer 13 gradually precipitates.

The present invention utilizes the fact that when refrigerant 134a is dissolved in refrigerant oil, the amount of infrared rays absorbed differs depending on the amount of dissolved refrigerant, and eliminates the two-layer separation between refrigerant oil and refrigerant 134a. This is to reduce the amount of refrigerant 134a dissolved. That is, when the motor of the hermetic compressor is stopped, the infrared concentration sensor 17 measures the refrigerant concentration in the refrigerating machine oil, and when the refrigerant concentration exceeds a predetermined value, the heater energization control device 16 and the heater 14 are activated. Turn on the electricity and heat the refrigerating machine oil.

When the refrigerant concentration in the hermetic compressor reaches a predetermined value or higher, the refrigerating machine oil and the refrigerant 134a are heated to lower the temperature. ), refrigeration oil and refrigerant 13
By eliminating the two-layer separation of 4a, refrigerant lubrication at the time of compressor startup is eliminated, and the amount of refrigerant 134a dissolved in the refrigerating machine oil is reduced, and the oil level is reduced. There is no risk of current leakage or electric shock. In addition, the heater 14 is connected to the infrared refrigerant concentration sensor 1.
By turning fi ON and OFF according to 7, power consumption can be reduced.

When this infrared concentration sensor 17 is used, it is possible to determine two-layer separation based on the infrared transmittance at a specific wavelength of refrigerating machine oil or refrigerant. Therefore, compared to the insulation resistance sensor 16 of the first embodiment, this sensor is less susceptible to the effects of water and ionic substances that dissolve in refrigerating machine oil and change electrical resistance, and has the feature of improved reliability during operation.

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

2o is a viscosity sensor attached below the oil supply pipe 8 of the compressor.

Reference numerals 21 and 22 designate a capillary and temperature sensor installed in the viscosity sensor 20, which detects the time during which a fixed volume of fluid flows through the capillary tube 21, detects the temperature of the refrigerating machine oil, and corrects the viscosity. - Next, its operation will be explained.

The shaft 2 is rotated by the rotational force of the motor section 12, operates the piston 6, and compresses the refrigerant in the compression chamber 7 formed by the sub-bearing 3, the bearing 4, and the cylinder 6. At this time, the heat of compression and the heat generated by the motor section 12 cause the temperature of the hermetic compressor to rise. Meanwhile, the compressed refrigerant is cooled in the refrigeration system and returned to the compressor. At this time, a liquid mixture of refrigerant RFC-134a and refrigerating machine oil is supplied to the mechanical part through the oil supply device 8 for lubrication.

In contrast to the above operation, when the compressor becomes high temperature due to heat generation during refrigerant compression or heat generation in the motor, the refrigerating machine oil and refrigerant RFC-134a begin to gradually dissolve and eventually freeze. Machine oil and refrigerant HFC-134 are dissolved and the two-layer separation is eliminated.

However, the temperature inside the compressor when the compressor drops.

As the pressure decreases, a refrigerant layer gradually precipitates.

In the present invention, when Reiw, 134a is dissolved in refrigerating machine oil,
Since the viscosity of the refrigerant oil and the refrigerant are different, the viscosity of the refrigerant oil is reduced, which eliminates the two-layer separation between the refrigerant oil and the refrigerant 134a, and the refrigerant 134a into the refrigerant oil.
This is to reduce the amount of dissolved. That is, when the motor of the hermetic compressor is stopped, the viscosity of the refrigerating machine oil is measured by the viscosity sensor 2o, and when the viscosity becomes less than a predetermined value, the heater energization control device 16 energizes the heater 15 and the refrigerating machine oil is heat up.

That is, by heating the hermetic compressor when the viscosity of the refrigerating machine oil in the hermetic compressor becomes equal to or less than a predetermined value using the heater 15 and the energization control device 16, the refrigerating machine oil and the refrigerant 13 are heated.
By heating 4a and raising the temperature, the refrigerating machine oil and refrigerant 134a are separated into two layers, and the oil level is lowered, which improves electrical insulation and prevents current from flowing in the casing, eliminating the risk of electrical leakage and electric shock. . Further, by turning off the heater 14 using the viscosity sensor 18, power consumption can be reduced.

When this viscosity sensor 2o is used, the viscosity is detected using the inherent shear stress, which is a physical property of the refrigerating machine oil or refrigerant, and the two-layer separation is determined. In addition, this physical property, viscosity, is not easily affected by deterioration of refrigerating machine oil or refrigerant. Therefore, the infrared sensor 17 of the second embodiment
Compared to conventional methods, the detection level can be maintained constant over a long period of time, improving reliability during operation. Further, compared to the insulation resistance sensor 16 of the first embodiment, water and ionic substances dissolved in the refrigerating machine oil do not affect the viscosity. That is, it goes without saying that reliability during operation is improved compared to the insulation resistance sensor 16.

Regarding the first to third embodiments, the refrigerant RFC-
1s4a and ester-based refrigerating machine oil, o Cold [HFC162a and alkylbenzene-based refrigerating machine oil 03 mixed refrigerant (HCFC22, HFC162a and HC
This also holds true in combinations of mixed refrigeration with FC124 or CFC114 [), alkylbenzene refrigerant machine oil type 03 mixed refrigerant, and naphthenic mineral oil.

Effects of the Invention A sealed casing enclosing a refrigerant and refrigeration oil in which two-layer separation occurs between the refrigerant and refrigeration oil, and the two-layer separation curve is convex upward; a mechanical part housed in the sealed casing; and a mechanical part. a motor section that drives the refrigerating machine, an oil supply device that conveys refrigerating machine oil to the mechanical section, a heater that is in close contact with the sealed casing, and a sensor that detects two-layer separation that is installed below the oil supply section of the oil supply device. Become.

Furthermore, an insulation resistance sensor is used as a sensor to detect the electrical resistance of the refrigerant and the refrigerating machine oil.

Furthermore, an infrared concentration sensor that detects the transmittance of infrared rays of the refrigerant and refrigerating machine oil is used as a sensor.

In addition, a viscosity sensor is used as a sensor to detect the viscosity of the refrigerant and refrigerating machine oil.

This will give you the following effects.

■ When the compressor is stopped, the sensor detects the point at which the refrigerant and refrigeration oil separate into two layers, and the heater heats the compressor, eliminating the two-layer separation between the refrigerant and refrigeration oil and providing refrigerant lubrication when the compressor is started. lose.

■ Due to the heating by the above-mentioned heater, the amount of refrigerant 134a dissolved in the refrigerating machine oil decreases, and the oil level decreases, which improves the insulation properties and prevents current from flowing in the casing, resulting in the risk of electrical leakage and electric shock. will no longer occur.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a compressor in a first embodiment of the present invention, FIG. 2 is a sectional view of a compressor in another embodiment of the present invention, and FIG. 3 is a sectional view of a compressor in another embodiment of the present invention. machine cross section,
FIG. 4 is a sectional view of a conventional compressor. 1... Mechanical part, 12... Motor part,
14...Heater, 16...Electrification control device, 16...Disconnection resistance sensor, 17...
...Far external radiation concentration sensor, 20...Viscosity sensor. Agent's name: Patent attorney Akira Okaji and 2 others l-senheya/ρ Motor master zt! is Closed Gushishik' /4 Heater 15-Through tM Sub-uplifting device l Bu Zhen wire Jiang J9 τnbu 1st fri 1- Isoki mark 10°"-Motor part 14°° Heater ts & t 1 @ ll'l J !JP % JL1
7° Approved, 1 piece, Figure 2, I-Horizontal stake mark 10-Motor part 14-TL-ter! 6 Energization control mechanism 1 20° fI! lI fake i iris 311! J

Claims (4)

[Claims] (1) A sealed casing containing refrigerant and refrigeration oil, a mechanical part housed in the sealed casing, a motor part that drives the mechanical part, an oil supply device that conveys the refrigeration oil to the mechanical part, and the sealed casing. A hermetic compressor consisting of a heater that is in close contact with the casing and a sensor that detects two-layer separation that is installed below the oil supply section of the oil supply device. (2) Claim (1) characterized in that the sensor is an insulation resistance sensor that detects the electrical resistance of the refrigerant and refrigeration oil.
Hermetic compressor as described. (3) The hermetic compressor according to claim (1), wherein the sensor is an infrared concentration sensor that detects the transmittance of infrared rays of the refrigerant and refrigerating machine oil. (4) The hermetic compressor according to claim (1), wherein the sensor is a viscosity sensor that detects the viscosity of the refrigerant and refrigerating machine oil.