JP2002317785A - Refrigerating device and refrigerant compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of a current refrigerant compressor using a method of estimating the oil concentration on the basis of the temperature of the mixture fluid to control the operation of the refrigerant compressor when the oil concentration exceeds a certain degree that both of a temperature sensor and a pressure sensor for detecting the pressure inside a shell are necessary to complicate the structure and that the control corresponding to the uneven distribution of the oil concentration is impossible. SOLUTION: A pair of electrodes are provided in a lower part inside the shell of the refrigerant compressor. Oil concentration of the mixture fluid is detected on the basis of an electrostatic capacity of the pair of electrodes, and the operation is controlled on the basis of the detected oil concentration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant compressor mounted on an air conditioner, a refrigerator and the like, and a refrigeration apparatus.

[0002]

2. Description of the Related Art FIG. 10 is a sectional view of a conventional hermetic scroll compressor disclosed in Japanese Patent Application Laid-Open No. Hei 5-209591. In FIG. 10, the hermetic scroll compressor has a shell 1
01, a compression mechanism 104 including a fixed scroll 102 and an orbiting scroll 103 disposed at an upper portion in the shell 101, and an electric mechanism including a stator 105 and a rotor 106 disposed below the compression mechanism 104. Part 107
A main shaft 108 that extends downward from the orbiting scroll 103 and is rotationally driven by the electric mechanism 107;
Suction pipe 10 for sucking refrigerant gas into shell 101
9, a discharge pipe 110 for discharging the compressed refrigerant gas to the outside of the shell 101, and a power supply power line for the stator 105 and a connection line for the thermal protector, which are welded to the shell 101 to be taken out of the shell 101. Sealed terminal 111 and shell 10
Refrigeration oil that is arranged at the lower part of
The pump is mainly constituted by a positive displacement oil pump 113 which feeds the compression mechanism 104 through an oil supply passage 112 inside the pump oil pump 08.

Next, the operation will be described. First, a refrigerant gas is sucked into the shell 101 from the suction pipe 109, flows into the shell 101, and then is compressed by the compression mechanism 104 constituted by the fixed scroll 102 and the orbiting scroll 103.
Inhaled to. Also, when power is supplied to the sealed terminal 111, a torque is generated between the stator 105 and the rotor 106, and the spindle 1
08 rotates. As a result, the orbiting scroll 103 connected to the main shaft 108 rotates, cooperates with the fixed scroll 102 to compress the fluid gas sucked into the compression mechanism 104, and then compresses the compressed refrigerant gas to the shell via the discharge pipe 110. Discharge outside 101.

At the same time, the refrigerating machine oil at the bottom of the shell 101 is sucked by the positive displacement oil pump 113 as the main shaft 108 rotates, and is lubricated to each bearing and the like through the oil supply passage 112. In addition, the supplied refrigerating machine oil descends in the shell 101 and returns to the bottom of the shell 101 again.

[0005]

However, in the conventional refrigerant compressor, the liquid refrigerant flows into the shell, and the liquid refrigerant dissolves in the refrigerating machine oil accumulated in the shell to form a mixed liquid.
When the oil concentration decreases, there is a problem that the lubrication characteristics of each bearing deteriorate.

[0006] In order to avoid this problem, there has conventionally been a method of estimating the oil concentration from the temperature of the mixed liquid and controlling the operation of the refrigerant compressor when the oil concentration exceeds a certain level. However, this method requires a temperature sensor and a pressure sensor for detecting the pressure in the shell, and thus has a problem that the configuration is complicated. Furthermore, in the method of estimating the oil concentration using the temperature sensor and the pressure sensor, since only the average value of the oil concentration of the mixed liquid in the shell is known, control corresponding to the case where the oil concentration is unevenly distributed is performed. There was a problem that it was not possible. For example, when the oil concentration is extremely low only in the portion near the suction port of the oil pump and high in other portions, the oil concentration of the mixed liquid supplied to each bearing and the like through the oil supply passage becomes low. . However, according to the conventional method, even in such a case, the compressor is operated as long as the average is within the normal range. Furthermore, when the oil concentration suddenly drops, the temperature change of the mixed liquid following the oil concentration appears after a certain period of time, so that the conventional method cannot cope with the rapid change of the oil concentration. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and can immediately detect the oil concentration of a mixed liquid in which a liquid refrigerant is dissolved in refrigeration oil retained in a lower portion of a shell, and furthermore, has a local effect. It is an object of the present invention to provide a refrigerant compressor that can cope with a case where the oil concentration is different.

[0008]

According to the present invention, there is provided a refrigerating apparatus comprising: a shell; a compression mechanism disposed at an upper portion in the shell; a refrigerating machine oil and a liquid refrigerant extending downward from the compression mechanism and staying at a lower portion in the shell. And a refrigerant compressor having a pair of electrodes provided at a lower part in the shell, and a refrigerant compressor connected to the pair of electrodes, and the oil concentration of the mixed liquid is determined from the capacitance of the electrodes. And control means for performing operation control based on the oil concentration.

Further, the control means adjusts the amount of refrigerant sucked into the refrigerant compressor according to the oil concentration.

Further, the control means stops the operation of the refrigerant compressor when the oil concentration falls below a predetermined value.

Further, when the oil concentration becomes equal to or less than a predetermined value, the control means opens a part of the bottom surface of the refrigerant compressor and discharges the mixed liquid from the refrigerant compressor.

A refrigerant compressor according to the present invention comprises a shell, a compression mechanism disposed at an upper portion in the shell, and a liquid mixture of refrigerating machine oil and liquid refrigerant extending downward from the compression mechanism and staying at a lower portion in the shell. And a pair of rod-shaped electrodes arranged on the lower inner surface of the shell.

[0013] The refrigerant compressor of the present invention comprises a shell, a compression mechanism disposed at an upper portion in the shell, and a mixed liquid of refrigerating machine oil and liquid refrigerant extending downward from the compression mechanism and staying at a lower portion in the shell. And a pair of electrodes provided on the inner bottom surface of the shell, the electrodes comprising:
The oil supply means is located near the lower opening provided for sucking the mixed liquid.

Further, the refrigerant compressor according to the present invention comprises a shell, a compression mechanism disposed at an upper portion in the shell, and a mixed liquid of refrigerating machine oil and liquid refrigerant extending downward from the compression mechanism and staying at a lower portion in the shell. And a refueling means for feeding the mixture to the compression mechanism. The refueling means has a suction pipe for sucking the mixed liquid, and a pair of electrodes parallel to the suction pipe.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a longitudinal sectional view of a hermetic scroll compressor according to Embodiment 1 of the present invention. In FIG. 1, the hermetic scroll compressor is arranged at a lower part of the compression mechanism 4 including a shell 1, a fixed scroll 2 and an orbiting scroll 3 arranged at an upper part in the shell 1, and a lower part of the compression mechanism 4. An electric mechanism 7 including a stator 5 and a rotor 6; and a main shaft 8 extending downward from the orbiting scroll 3 and driven to rotate by the electric mechanism 7.
And a suction pipe 9 for sucking refrigerant gas into the shell 1
And a discharge pipe 1 for discharging the compressed refrigerant gas out of the shell 1
0, a sealing terminal 11 welded to the shell 1 to take out a power supply power line of the stator 5 and a connection line of the thermal protector to the outside of the shell 1, and are disposed at a lower portion of the shell 1 and stay at the lower portion. It is mainly constituted by a positive displacement oil pump 13 that sends the mixture through the oil supply passage 12 in the main shaft 8 to the compression mechanism 4. Further, on the inner bottom surface of the shell 1, a pair of cylindrical electrodes 20 composed of double cylinders for measuring dielectric properties are arranged. The pair of cylindrical electrodes 20 are JISC 2
It has a shape similar to that illustrated in 101. The oil supply passage 12 and the positive displacement oil pump 13 constitute oil supply means.

Next, a control operation using the oil concentration detection control means including the pair of cylindrical electrodes 20 will be described with reference to a block diagram of the oil concentration detection control means of FIG. 2 and a control flowchart of FIG. Each electrode of the pair of cylindrical electrodes 20 is connected to a relative permittivity detecting unit 30 such as an LCR meter, and the relative dielectric constant of a mixed liquid of refrigerating machine oil and liquid refrigerant between the electrodes is determined based on the capacitance between the two electrodes. A rate is detected (step (hereinafter, referred to as “S”) 1).

Next, the relative permittivity detected by the relative permittivity detecting section 30 is sent to the oil concentration detecting section 31, and the oil concentration is detected based on the oil concentration-relative permittivity correspondence graph shown in FIG. (S2). In addition, since the relative permittivity of the liquid refrigerant and the refrigerating machine oil is generally significantly different, the oil concentration can be determined from the relative permittivity with considerable accuracy. Further, the correspondence graph of FIG. 4 needs to be measured in advance by an experiment and stored in the oil concentration detection unit 31.

Next, the oil concentration detected by the oil concentration detecting unit 31 is sent to the control unit 32, and control corresponding to the oil concentration is performed. Specifically, first, it is determined whether or not the oil concentration is equal to or less than 20% (S3). If it is determined that the oil concentration is equal to or less than 20%, the operation of the refrigerant compressor itself is stopped (S4). This stop is performed by cutting off the circuit between the power supply power line connected to the sealed terminal 11 and the electric mechanism 7.

If it is determined in S3 that the oil concentration exceeds 20%, it is next determined whether the oil concentration is 50% or less (S5). Here, when it is determined to be 50% or less, the liquid back amount is adjusted (S6), and when it is determined that the oil concentration exceeds 50%, the process returns to S1. Note that the adjustment of the amount of liquid back refers to the evaporator 5 as shown in the refrigerant circuit diagram of FIG.
0, a compressor 51, a condenser 52, and an expansion valve 53 are connected by a main pipe 54. Further, a main pipe 54 between the evaporator 50 and the compressor 51, and a main pipe between the condenser 52 and the expansion valve 53. A configuration in which up to 54 is connected by a bypass pipe 57 having a throttle 55 and a flow meter 56 is to adjust the throttle 55 to adjust the amount of refrigerant bypassed by the bypass pipe 57. The amount of refrigerant flowing into the compressor 51 decreases when the opening degree of the throttle 55 is increased, and conversely, the amount of refrigerant flowing into the compressor 51 increases when the opening degree of the throttle 55 is reduced.

As described above, in this embodiment, the oil concentration of the mixed liquid obtained by mixing the refrigerating machine oil and the liquid refrigerant staying in the lower portion of the shell is measured by the dielectric constant, and the operation control of the refrigerant compressor is performed according to the measured oil concentration. Since it is performed, it is possible to follow a change in the oil concentration in a timely manner with a simple configuration, and to prevent a failure of the refrigerant compressor due to poor lubrication.

In this embodiment, the oil concentration detecting section 31 and the control section 32 are configured separately. However, both functions may be incorporated in, for example, a microcomputer. Although the scroll compressor is used in this embodiment, a reciprocating compressor or a rotary compressor may be used.

Embodiment 2 FIG. FIG. 6 is a longitudinal sectional view of a refrigerant compressor according to Embodiment 2 of the present invention. In the refrigerant compressor of FIG. 1, a pair of rod-shaped electrodes is used for measuring the capacitance of the mixed liquid, and the lower part of the shell is used. It is designed to be installed on the side of. In FIG. 6, the same components as those in FIG. 1 and corresponding components are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 6, reference numeral 21 denotes a pair of rod electrodes provided from the lower inner surface of the shell 1 toward the positive displacement oil pump. When a pair of cylindrical electrodes are used as in the first embodiment, the space between the electrodes is narrow, and furthermore, accurate mixing is performed when refrigerant gas enters between the electrodes unless the electrodes are installed vertically. Since it becomes impossible to measure the relative dielectric constant of the liquid, it was necessary to install a pair of cylindrical electrodes on the inner bottom surface of the shell, but if a pair of rod electrodes is used as in Embodiment 2, , Can be installed on the side of the shell, and the overall height of the refrigerant compressor can be reduced.

Embodiment 3 FIG. FIG. 7 is a longitudinal sectional view of a refrigerant compressor according to Embodiment 3 of the present invention. In the refrigerant compressor of FIG. 6, a pair of rod electrodes for measuring the capacitance of a mixed liquid is connected to an inlet of an oil pump. This is provided so as to be located in the vicinity. In FIG. 7, the same components as those in FIG. 5 and corresponding components are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 7, reference numeral 22 denotes a pair of rod electrodes provided upward from the inner bottom surface of the shell 1. The position is substantially at the center of the inner bottom surface, and is located near the suction port of the positive displacement oil pump 13. The oil concentration of the mixed solution staying at the lower part in the shell is not always constant and may be unevenly distributed. In this case, since the mixed liquid near the suction port of the oil pump 13 is sucked and carried through the oil supply passage, it is necessary to take prompt action when the oil concentration at the suction port is low. However, on the contrary, even if the oil concentration is low in a portion other than the vicinity of the suction port of the oil pump 13, the operation is not hindered so much.

In this embodiment, since a pair of rod electrodes is provided near the suction port of the positive displacement oil pump 13, a value close to the oil concentration of the mixed liquid sent to the compression mechanism 4 can be detected.
Efficient control can be performed.

Embodiment 4 FIG. 8 is a longitudinal sectional view of a refrigerant compressor according to Embodiment 4 of the present invention. In the refrigerant compressor of FIG. 1, a pair of cylindrical electrodes for measuring capacitance of a mixed liquid and an oil pump are integrated. It is what was constituted. In FIG. 8, the same components as those in FIG. 1 and corresponding components are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 8, reference numeral 23 denotes a positive displacement oil pump, which includes a driving part 23a, a suction pipe part 23b extending directly downward from the driving part 23a, and a suction pipe 23b extending parallel to the suction pipe part 23b. , The length of which is the suction pipe 23b
A second cylindrical electrode 23c which is substantially the same as the first cylindrical electrode 23c and which is arranged so as to surround the suction tube 23b and the first cylindrical electrode 23c, and has a length substantially the same as that of the suction tube 23b. This is mainly composed of the mold electrode 23d. Note that the first cylindrical electrode 23c and the second cylindrical electrode 23d form a pair of cylindrical electrodes. Reference numeral 24 denotes a terminal inserted into the lower part of the shell 1 from the outside to the inside. The terminal 24 is connected to each of the first cylindrical electrode 23c and the second cylindrical electrode 23d via a cable 25.

In this embodiment, the positive displacement oil pump 23
A pair of cylindrical electrodes are arranged in the vicinity of the suction pipe section 23b so as to surround the suction pipe section 23b. Therefore, the oil concentration of the mixed liquid absorbed by the suction pipe section 23b with the pair of cylindrical electrodes is Can be detected, and efficient control can be performed.

Embodiment 5 FIG. 9 is a longitudinal sectional view of a refrigerant compressor according to Embodiment 5 of the present invention. In the refrigerant compressor of FIG. 1, an oil removal device that can be opened and closed by a control unit is provided. In FIG. 9, the same components as those in FIG. 1 and corresponding components are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 9, reference numeral 26 denotes an oil take-out device, which is mainly constituted by an opening / closing device 26a provided at a lower portion of the shell 1 and an oil take-out pipe 26b connected to the open / close device 26a. The opening and closing control of the opening and closing device 26a is controlled by the control unit 32. Also, the oil extraction pipe 26
b is connected to an oil separator (not shown).

Next, the operation will be described. Control unit 32
Then, the oil concentration determined by the oil concentration detection unit 31 is a predetermined value,
For example, if it is less than 30%, the opening / closing device 26a
And open a predetermined amount from the lower part of the shell 1, for example, the shell 1
The height of the liquid mixture remaining in the lower part of the pump is
3. Take out the mixture until it is slightly above the inlet of 3. The mixed liquid is sent to the oil separator via the oil take-out pipe 26b, and is separated into the refrigerant and the refrigerating machine oil by the oil separator, and the refrigerating machine oil is returned to the refrigerant compressor again.

Usually, the specific gravity of the liquid refrigerant is larger than the specific gravity of the refrigerating machine oil, so that the oil concentration is lower at the bottom of the shell.
In this configuration, since the mixed solution having a low oil concentration retained at the bottom in the shell is directly taken out, the oil concentration can be quickly adjusted. Further, since the oil of the mixed liquid is separated and returned to the refrigerant compressor oil, the oil concentration can be increased.

[0034]

The refrigerating apparatus according to the present invention detects the oil concentration of the mixed liquid from the capacitance of a pair of electrodes provided in the shell, and performs control based on the detected oil concentration. In a timely manner.

Further, the amount of the refrigerant sucked into the refrigerant compressor is adjusted in accordance with the oil concentration, or the operation of the refrigerant compressor is stopped when the oil concentration falls below a predetermined value. Therefore, failure of the refrigerant compressor due to poor lubrication can be prevented.

Further, when the oil concentration becomes lower than a predetermined value, a part of the bottom surface of the refrigerant compressor is opened to discharge the mixed liquid from the refrigerant compressor. Becomes possible.

In addition, since a pair of rod-shaped electrodes are arranged on the lower inner side surface of the shell, it is possible to prevent the shell from being enlarged by the electrode arrangement.

Further, since the pair of electrodes are located near the lower opening provided for sucking the mixture of the oil supply means, the oil concentration close to the oil concentration sent to the compression mechanism can be detected. And efficient control can be performed.

Further, since the oil supply means has a suction pipe for sucking the mixed liquid and a pair of electrodes parallel to the suction pipe, the oil concentration is equal to the oil concentration sent to the compression mechanism. Can be detected, and efficient control can be performed. .

[Brief description of the drawings]

FIG. 1 is a sectional view of a hermetic scroll compressor according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram of oil concentration detection control means.

FIG. 3 is a control flowchart.

FIG. 4 is a diagram showing the correspondence between oil concentration and non-dielectric constant.

FIG. 5 is a refrigerant circuit diagram.

FIG. 6 is a sectional view of a hermetic scroll compressor according to Embodiment 2 of the present invention.

FIG. 7 is a sectional view of a hermetic scroll compressor according to Embodiment 3 of the present invention.

FIG. 8 is a sectional view of a hermetic scroll compressor according to Embodiment 4 of the present invention.

FIG. 9 is a sectional view of a hermetic scroll compressor according to Embodiment 5 of the present invention.

FIG. 10 is a cross-sectional view of a conventional hermetic scroll compressor.

[Explanation of symbols]

1 shell, 2 fixed scroll, 3 swinging scroll, 4 compression mechanism, 5 stator, 6 rotor,
7 electric mechanism section, 8 main shaft, 9 suction pipe, 10
Discharge pipe, 11 sealed terminal, 12 oil supply passage, 13
Positive displacement oil pump, 20 pair of cylindrical electrodes, 21 pair of rod electrodes, 22 pair of rod electrodes, 23 positive displacement oil pump, 23a drive unit, 23b suction pipe unit,
23c first cylindrical electrode, 23d second cylindrical electrode, 24 terminals, 25 cable, 26 oil extraction device, 26a switchgear, 26b oil extraction tube,
30 Non-dielectric constant detecting section, 31 Oil concentration detecting section, 32
Control unit, 50 evaporator, 51 compressor, 52 condenser, 53 expansion valve, 54 main piping, 55 throttle, 56 flow meter, 57 bypass piping.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F25B 49/02 550 F25B 49/02 550 570 570Z (72) Inventor Jun Nagata 2-chome Otemachi 2-chome, Chiyoda-ku, Tokyo No. 6-2 Mitsubishi Electric Engineering Co., Ltd. F-term (reference) 3H003 AA05 AB03 AC03 BD07 CC04 CF01 3H029 AA02 AA14 AB03 BB01 BB42 BB51 BB54 CC15 CC24 CC25 CC35 CC59 CC65 CC83

Claims (7)

[Claims] 1. A shell, a compression mechanism disposed at an upper portion in the shell, and a mixed liquid of refrigerating machine oil and liquid refrigerant extending downward from the compression mechanism and staying at a lower portion in the shell to the compression mechanism. A refrigerant compressor including a refueling means for feeding and a pair of electrodes provided at a lower portion in the shell; and a detection device connected to the pair of electrodes and detecting an oil concentration of the mixed liquid from a capacitance of the electrodes. And a control unit for performing operation control based on the oil concentration. 2. The refrigeration apparatus according to claim 1, wherein the control means adjusts the amount of refrigerant sucked into the refrigerant compressor according to the oil concentration. 3. The refrigeration apparatus according to claim 1, wherein the control means stops the operation of the refrigerant compressor when the oil concentration becomes equal to or less than a predetermined value. 4. The control means opens a part of the bottom surface of the refrigerant compressor when the oil concentration becomes equal to or less than a predetermined value, and discharges the mixed liquid from the refrigerant compressor. The refrigeration apparatus according to claim 1, wherein 5. A shell, a compression mechanism disposed at an upper part in the shell, and a mixed liquid of refrigerating machine oil and liquid refrigerant extending downward from the compression mechanism and staying at a lower part in the shell to the compression mechanism. A refrigerant compressor comprising: a refueling means for feeding; and a pair of rod-shaped electrodes disposed on an inner surface of a lower portion of the shell. 6. A shell, a compression mechanism disposed at an upper part in the shell, and a mixed liquid of refrigerating machine oil and liquid refrigerant extending downward from the compression mechanism and staying at a lower part in the shell to the compression mechanism. A fuel supply means, and a pair of electrodes provided on the inner bottom surface of the shell, wherein the electrode is located near a lower opening provided for sucking the mixture of the fuel supply means. Refrigerant compressor. 7. A shell, a compression mechanism disposed at an upper portion in the shell, and a mixed liquid of refrigeration oil and liquid refrigerant extending downward from the compression mechanism and staying at a lower portion in the shell to the compression mechanism. A refrigerant compressor, comprising: a refueling means for feeding, the refueling means having a suction pipe for sucking the mixed liquid, and a pair of electrodes parallel to the suction pipe.