JP2005016742A - Heat pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump capable of keeping high performance by using a screw type compressor and an expansion machine. <P>SOLUTION: In this heat pump, the screw type expansion machine 105 comprising a pair of male and female screw rotors 13, 14 engaged with each other, similarly as the screw compressor 101, is applied. A male rotor 11 of the screw compressor 101 and the male rotor 13 of the expansion machine share a rotor shaft, a female rotor 12 of the screw compressor 101 and the female rotor 14 of the expansion machine 105 shares a rotor shaft, and a casing 14 is composed of a compression casing part 15a at a compressor side, an expansion machine casing part 15c at an expansion machine side, and an intermediate casing part 15c mounted therebetween in a state of keeping the air-tightness to integrally fixing them. Partitions 31a, 31b are mounted to shield a screw rotor accommodating space of the screw compressor 101 and a screw rotor accommodating space of the expansion machine 105. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat pump using an expander that is driven by a rotor shaft that is coaxially and integrally coupled with a rotor shaft of a compressor.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a heat pump using an expander that is driven by a rotor shaft that is coupled coaxially with a rotor shaft of a compressor so as to be integrally rotatable is known (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-8-42930 (paragraph [0025], FIG. 9)
[0004]
Patent Document 1 discloses a heat pump 100 as shown in FIG. 8, and is coupled to the heat pump 100 coaxially with a rotor shaft 102 of a compressor 101 via a coupling 103 so as to be integrally rotatable. An expander 105 driven by the rotor shaft 104 is used. The compressor 101 has an input shaft 106 coupled to an output shaft 109 of a motor 108 via a coupling 107 and is driven by the motor 108.
[0005]
In the refrigerant circulation flow path I including the compressor 101, the condenser 111, the expander 105, and the evaporator 112, the high-pressure and high-temperature refrigerant gas compressed by the compressor releases heat in the condenser 111. It becomes a high-pressure fluid and flows from the condenser 111 to the expander 105. This high-pressure fluid expands in the expander 105, rotates the rotor (impeller) using the expansion energy, becomes a low-pressure two-phase flow, and flows to the evaporator 112. Furthermore, the refrigerant absorbs heat in the evaporator 112 and vaporizes, and returns to the compressor 101. The expansion energy is recovered as a part of the energy for rotating the rotor of the compressor 101 via the rotor of the expander 105, the burden on the motor 108 is reduced, and the refrigerant returned from the evaporator 112 is recovered by the compressor 101. Compressed and cycled repeatedly.
[0006]
Patent Document 1 discloses a heat pump in which a compressor 101 and an expander 105 are formed using an integral casing. In particular, FIG. 9 of Patent Document 1 includes a turbine-type expander 105, A heat pump using a screw type compressor 101 is disclosed.
[0007]
[Problems to be solved by the invention]
In the screw-type compressor 101 described above, the gas confinement space formed between the pair of male and female screw rotors that mesh with each other and the inner surface of the casing that houses the pair of screw rotors is reduced as the screw rotor rotates. It is a type of positive displacement compressor that compresses gas by moving. On the other hand, the turbine type expander 105 has an impeller that is rotated by gas expansion energy, that is, a rotor, and the rotation thereof is much faster than the rotation of the screw rotor. As described above, the screw-type compressor 101 and the turbine-type expander 105 are different devices that use different phenomena and have no structural similarity. For example, a lubricating oil supply mechanism for each bearing portion or the like. Need to be provided separately, and the entire oil supply system becomes complicated, so that the heat pump itself becomes large and the probability of occurrence of a failure also increases.
[0008]
Such a problem is solved by making the expander 105 a screw type. In this case, in the expander 105, the gas formed between the pair of male and female screw rotors that mesh with each other and the inner surface of the casing that accommodates the pair of screw rotors, contrary to the screw-type compressor 101 described above. The confined space is expanded with the rotation of the screw rotor, so that the gas is expanded.
[0009]
When the compressor 101 and the expander 105 are formed using an integral casing, if the tooth space of the screw rotor of the compressor 101 and the tooth space of the screw rotor of the expander 105 communicate with each other, the compressor The refrigerant leaks from 101 to the expander 105, the amount of the refrigerant passing through the condenser 111 is reduced, and the performance of the heat pump 100 is deteriorated.
The present invention has been made in order to eliminate such conventional problems, and intends to provide a heat pump that uses a screw-type compressor and an expander and can maintain good performance. It is.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the first invention is an oil-cooled screw compressor and a refrigerant compressed here and condensed in a condenser to be converted into a gas / liquid two-phase flow by rotation of a rotor to an evaporator. And the expander to be fed out using an integral casing, and at least one rotor shaft of the oil-cooled screw compressor and at least one rotor shaft of the expander are coaxially arranged so as to be integrally rotatable, and are driven by the same drive In the heat pump driven by the section, the expander is a screw type including a pair of male and female screw rotors that engage with each other like the oil-cooled screw compressor, and the male rotor of the oil-cooled screw compressor and the expander The rotor shafts of the male rotor are coaxially provided so as to be integrally rotatable, and the rotor shafts of the female rotor of the oil-cooled screw compressor and the female rotor of the expander are connected to each other. The casing is rotatably provided on the same axis, and the casing is interposed between the compressor casing portion on the compressor side and the expander casing portion on the expander side in a state of maintaining airtightness therebetween, and the two are fixed integrally. An intermediate casing portion is provided, and a partition plate is provided to block the screw rotor housing space of the oil-cooled screw compressor and the screw rotor housing space of the expander.
[0011]
In the second aspect of the invention, in addition to the structure of the first aspect of the invention, the partition plate includes an oil supply hole for supplying oil around each of the rotor shafts passing through the partition plate.
[0012]
In the third invention, in addition to the structure of the second invention, an annular member made of resin or non-ferrous metal is interposed in the annular space portion between the rotor shaft side opening end of the oil supply hole and each rotor shaft. It was set as the structure made to do.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
1 to 7 show a heat pump 1 according to the present invention. As shown in FIG. 1, the heat pump 1 includes a compressor 101, a condenser 111, an expander 105, and an evaporator 112 as described above, and an oil separator / recovery unit 113 between the compressor 101 and the condenser 111. And a refrigerant circulation path I including these is formed. Further, the input shaft 106 of the compressor 101 is coupled to the output shaft 109 of the motor 108 via a coupling 107 so as to be integrally rotatable. Furthermore, from the oil reservoir 113A at the lower part of the oil separator / recovery unit 113, the oil flow path II that leads to the gas confinement space in the compressor 101 after the oil once accumulated therein is cooled by the oil cooler 114 is provided. Is provided.
[0014]
As shown in FIG. 2, the compressor 101 is an oil-cooled screw compressor having a pair of male and female screw rotors 11 and 12 that mesh with each other, and the expander 105 has a pair of male and female screw rotors 13 and 14 that mesh with each other. Each is housed rotatably in the integral casing 15.
[0015]
More specifically, the casing 15 includes a compressor casing portion 15a, an intermediate casing portion 15b, and an expander casing portion 15c. The screw rotors 11 and 12 are disposed in the compressor casing portion 15a, and the screw rotors 13 and 14 are disposed. An intermediate casing portion 15b is interposed between the compressor casing portion 15a and the expander casing portion 15c while being accommodated in the expander casing portion 15c. The male screw rotor 11 of the compressor 101 and the male screw rotor 13 of the expander 105 share the rotor shaft 16, and the rotor shaft 17 extending to the other side of the screw rotor 11 can be rotated by a bearing 18. The rotor shaft 19 that is supported and extends to the other side of the screw rotor 13 is rotatably supported by a bearing 21. The rotor shaft 17 further extends through the compressor casing portion 15a via the mechanical seal 22 and serves as the input shaft 106 described above. Furthermore, the screw rotor 12 on the female side of the compressor 101 and the screw rotor 14 on the female side of the expander 105 share the rotor shaft 23, and the rotor shaft 24 extending to the other side of the screw rotor 12 can be rotated by a bearing 25. The rotor shaft 26 that is supported and extends to the other side of the screw rotor 14 is rotatably supported by a bearing 27.
[0016]
The screw rotor accommodating space in the compressor 101 and the screw rotor accommodating space in the expander 105 are blocked by two partition plates 31 a and 31 b that sandwich the rotor shafts 16 and 23. In order to prevent gaps between the compressor casing portion 15a and the intermediate casing portion 15b, and between the intermediate casing portion 15b and the expander casing portion 15c, the dimensions in the rotor axial direction are the intermediate casing 15b. Is larger than the partition plates 31a and 31b. For this reason, in the illustrated embodiment, a minute gap is generated between the partition plates 31 a and 31 b and the end faces of the screw rotors 11 and 12.
[0017]
3, the compressor casing portion 15a has a compressor suction port 32 and a compressor discharge port 33, and the expander casing portion 15c has an expander suction port 34 and an expander discharge port 35. Are formed, and each form a part of the circulation flow path I.
[0018]
The refrigerant sucked into the compressor 101 from the compressor suction port 32 flows into the gas confined space formed between the screw rotors 11 and 12 of the compressor 101 and the inner surface of the compressor casing portion 15a. The oil is compressed while being supplied with oil from the passage II, and is discharged from the compressor discharge port 33 to the oil separator / recovery unit 113 with accompanying oil. In the oil separator / collector 113, the refrigerant and the oil are separated, and the separated oil is temporarily stored in the oil reservoir 113A, and the refrigerant from which the oil has been separated is sent out to the condenser 111. As described above, the oil in the oil reservoir 113A is guided to the gas confined space in the compressor 101 by the oil flow path II in which the oil cooler 114 is interposed, and is repeatedly circulated and used. On the other hand, after the refrigerant is condensed in the condenser 111, the refrigerant is confined in a space formed between the screw rotors 13 and 14 of the expander 105 and the inner surface of the expander casing portion 15c from the expander suction port 34. 13 and 14 is expanded as a two-phase flow of gas and liquid from the expander discharge port 35 to the evaporator 112 where the heat is absorbed and evaporated, and the compressor suction port of the compressor 101 Return to 32 and repeat the cycle.
[0019]
When the refrigerant is compressed by the compressor 101 and expanded by the expander 105, radial and axial forces are applied to the screw rotors 11 and 12 of the compressor 101 and the screw rotors 13 and 14 of the expander 105, respectively. Although acting, this force is received by the bearings 18, 21, 25 and 27 via the rotor shafts 17, 19, 24 and 26. Further, leakage of the refrigerant from the portion where the rotor shaft 17 passes through the compressor casing portion 15 a is prevented by the mechanical seal 22.
[0020]
Further, when the compressor discharge port 33 and the expander suction port 34 or the screw rotor accommodating space of the compressor 101 and the screw rotor accommodating space of the expander 105 communicate with each other, the amount of refrigerant passing through the condenser 111 However, in the heat pump 1, partition plates 31a and 31b are provided to minimize the flow of refrigerant between the two ports or between the two spaces. It is formed as follows. The pressure in the intermediate casing portion 15b is about 10 MPa, and the inside of the intermediate casing portion 15b needs to be shut off from the outside. The intermediate casing portion 15b is airtightly coupled to each of the compressor casing portion 15a and the expander casing portion 15c. The inside is completely shut off from the outside, and leakage of the refrigerant from the inside to the outside is also prevented. In the illustrated embodiment, the partition plates 31a and 31b are fixed to the end surface of the expander casing portion 15c. However, the partition plates 31a and 31b may be fixed to the end surface of the compressor casing portion 15a.
[0021]
Since there is a slight gap between the rotor shafts 16 and 23 and the partition plates 31a and 31b and there is a possibility that the refrigerant leaks from there, as shown in FIGS. 5 and 6, for example, the rotor shaft is connected to the partition plate 31a. It is preferable to provide an oil supply hole 41 for supplying oil to the outer peripheral portions of 16 and 23. As a result, the small gap can be filled with oil, oil leakage from the gap can be reduced, and deterioration of the performance of the heat pump 1 can be suppressed.
[0022]
In addition, the smaller the gap between the rotor shafts 16 and 23 and the partition plates 31a and 31b, the better. However, when the rotor shafts 16 and 23 and the partition plates 31a and 31b come into contact with each other when the gap is reduced too much, In the case of iron, the contact portion is melted and welded by heat, and the welded portion is peeled off, and the above gap is enlarged, leading to a decrease in performance of the heat pump 1. Therefore, as shown in FIG. 7, in addition to the oil supply hole 41, a resin (eg, fluorocarbon resin) is formed in the annular space between the rotor shaft side opening end of the oil supply hole 41 and the rotor shafts 16 and 23. Or an annular member 51 made of a non-ferrous metal (eg, white metal) is preferably interposed. Thereby, the occurrence of the situation of the above-described welding and peeling and further expansion of the gap is avoided, and the deterioration of the performance of the heat pump 1 can be prevented more reliably.
In FIG. 7, only the rotor shaft 16 is shown, but the annular member 51 is also provided on the outer peripheral portion of the rotor shaft 23.
[0023]
【The invention's effect】
As apparent from the above description, according to the first invention, the oil-cooled screw compressor and the refrigerant compressed here and condensed in the condenser are converted into a two-phase flow of gas and liquid by rotation of the rotor. The expander sent to the evaporator is formed using an integral casing, and at least one rotor shaft of the oil-cooled screw compressor and at least one rotor shaft of the expander are coaxially arranged so as to be integrally rotatable. In the heat pump driven by the same drive unit, the expander is a screw type including a pair of male and female screw rotors that mesh with each other in the same manner as the oil-cooled screw compressor, and the male rotor of the oil-cooled screw compressor The rotor shafts of the male rotor of the expander are coaxially provided so as to be integrally rotatable, and the female rotor of the oil-cooled screw compressor and the rotor of the female rotor of the expander The casings are provided coaxially so that they can rotate together, and the casing is interposed between the compressor casing portion on the compressor side and the expander casing portion on the expander side in a state of maintaining airtightness therebetween, and the two are integrated. And a partition plate that cuts off the screw rotor accommodating space of the oil-cooled screw compressor and the screw rotor accommodating space of the expander.
For this reason, the leakage of the refrigerant from the compressor side to the expander side, and thereby the decrease in the amount of the refrigerant passing through the condenser can be minimized, and the performance deterioration of the heat pump can be suppressed. The effect of.
[0024]
According to the second invention, in addition to the structure of the first invention, the partition plate includes an oil supply hole for supplying oil around each of the rotor shafts penetrating therethrough.
For this reason, there exists an effect that the effect by 1st invention can be made more remarkable.
[0025]
According to the third invention, in addition to the structure of the second invention, an annular member made of resin or non-ferrous metal in the annular space between the rotor shaft side opening end of the oil supply hole and each of the rotor shafts It is the structure which intervened.
For this reason, there exists an effect that the effect by 2nd invention can be improved further.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of a heat pump according to the present invention.
2 is a cross-sectional view showing a state in which the compressor and the expander shown in FIG. 1 are cut along a plane including the axial centers of a pair of male and female screw rotors.
3 is a cross-sectional view taken along line III-III in FIG.
4 is a cross-sectional view taken along the line IV-IV in FIG. 3;
5 is a cross-sectional view corresponding to FIG. 3 of another heat pump according to the present invention.
6 is a cross-sectional view taken along line VI-VI in FIG.
FIG. 7 is an enlarged cross-sectional view of still another heat pump partition plate according to the present invention and a portion of a rotor shaft passing therethrough.
FIG. 8 is a diagram showing an overall configuration of a conventional heat pump.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heat pump 11, 12 Screw rotor 13, 14 Screw rotor 15 Casing 15a Compressor casing part 15b Intermediate casing part 15c Expander casing part 16, 17 Rotor shaft 18 Bearing 19 Rotor shaft 21 Bearing 22 Mechanical seal 23, 24 Rotor shaft 25 Bearing 26 Rotor shaft 27 Bearing 31a, 31b Partition plate 32 Compressor suction port 33 Compressor discharge port 34 Expander suction port 35 Expander discharge port 41 Oil supply hole 51 Annular member 101 Compressor 105 Expander 106 Input shaft 107 Coupling 108 Motor 109 Output shaft 111 Condenser 112 Evaporator 113 Oil separation and recovery unit 113A Oil reservoir I Circulation channel II Oil channel

Claims (3)

An integrated casing is used to form an oil-cooled screw compressor and an expander that sends the refrigerant compressed here and condensed in the condenser into a gas / liquid two-phase flow by rotation of the rotor to the evaporator. And at least one rotor shaft of the oil-cooled screw compressor and at least one rotor shaft of the expander are arranged coaxially so as to be integrally rotatable, and in a heat pump driven by the same drive unit,
Like the oil-cooled screw compressor, the expander is a screw type having a pair of male and female screw rotors engaged with each other,
The respective rotor shafts of the male rotor of the oil-cooled screw compressor and the male rotor of the expander are coaxially provided so as to be integrally rotatable, and the rotor of the female rotor of the screw compressor and the female rotor of the expander The shafts are provided on the same axis so that they can rotate together,
The casing is formed by a compressor casing part on the compressor side, an expander casing part on the expander side, and an intermediate casing part that fixes both of them together while maintaining airtightness between them,
A heat pump, comprising: a partition plate that cuts off a screw rotor housing space of the oil-cooled screw compressor and a screw rotor housing space of the expander. 2. The heat pump according to claim 1, wherein the partition plate includes an oil supply hole that supplies oil around each of the rotor shafts passing through the partition plate. 3. The heat pump according to claim 2, wherein an annular member made of a resin or a non-ferrous metal is interposed in an annular space portion between the opening end portion of the oil supply hole on the rotor shaft side and each rotor shaft. .

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