WO2019093107A1

WO2019093107A1 - Liquid-cooled screw compressor

Info

Publication number: WO2019093107A1
Application number: PCT/JP2018/039178
Authority: WO
Inventors: 孝二田中; 透野口; 広宣坂口; 貴徳今城
Original assignee: 株式会社神戸製鋼所
Priority date: 2017-11-09
Filing date: 2018-10-22
Publication date: 2019-05-16
Also published as: JP6850243B2; CN111279080B; JP2019085967A; CN111279080A

Abstract

This compressor 1 is provided with: a male rotor 50; a female rotor 60 which is meshed with the male rotor 50 and has more teeth than the male rotor 50; a rotor casing 10 which defines a male rotor compartment 31 for housing the male rotor 50 and a female rotor compartment 32 for housing the female rotor 60; and an oil fill opening 13 which is disposed only on the female rotor compartment 32 side of the rotor casing 10. In a cross section perpendicular to a rotating axis of the female rotor 60, a lowest point P3 of the male rotor compartment 50 is positioned lower than a cusp point 14 positioned at the lowest level at which the male rotor compartment 31 and the female rotor compartment 32 are connected.

Description

Liquid-cooled screw compressor

The present invention relates to a liquid-cooled screw compressor.

An oil-cooled screw compressor, which is a type of liquid-cooled screw compressor, in which the heat exchange between gas and oil during compression is promoted by devising the arrangement of injection nozzles (fueling ports) For example, it is disclosed in Patent Document 1. In the oil-cooled screw compressor of Patent Document 1, the injection direction from the injection nozzle into the compression chamber (rotor chamber) is opposite to the rotation direction of the screw rotor. As a result, the time for the oil to travel through the gas in the compression chamber is secured for a long time, and the heat exchange between the gas and the oil is promoted.

Unexamined-Japanese-Patent No. 9-151870 gazette

In general, the male rotor has a high rotational speed because it has a smaller number of teeth than the female rotor. Therefore, when the fluid is supplied to the male rotor and the fluid is supplied to the female rotor, a larger load is often generated when the fluid is supplied to the male rotor.

The oil-cooled screw compressor of Patent Document 1 is provided with oil supply ports to both a male rotor and a female rotor. Therefore, since it is configured to feed not only the female rotor but also the male rotor, the load becomes large because the oil is stirred at high speed by the male rotor, power loss occurs, and the compression efficiency may be deteriorated.

An object of the present invention is to reduce the stirring load of a liquid and improve the compression efficiency in a liquid-cooled screw compressor.

The present invention defines a male rotor, a female rotor meshing with the male rotor and having more teeth than the male rotor, a male rotor chamber accommodating the male rotor, and a female rotor chamber accommodating the female rotor. A rotor casing and a liquid supply port provided only on the female rotor chamber side of the rotor casing, and the lowermost point of the male rotor chamber is, in a cross section perpendicular to the rotation axis of the female rotor, A liquid-cooled screw compressor is provided, which is located below a cusp point located at the lowest position connecting a male rotor chamber and the female rotor chamber.

According to this configuration, since the female rotor has fewer teeth than the male rotor, the rotational speed of the female rotor can be made slower than the rotational speed of the male rotor. Furthermore, in the above configuration, since the liquid supply port is provided so that the liquid is supplied only to the female rotor having a low rotational speed, it is possible to prevent an overload due to high-speed stirring of the liquid on the male rotor side. Therefore, since the power loss accompanying the liquid agitation can be reduced, the compression efficiency can be improved. Further, the liquid supplied to the female rotor chamber is also supplied to the male rotor chamber as the female rotor meshes with the male rotor. Since the lowest point of the male rotor chamber is located below the cusp point, it is possible to prevent the liquid that has fallen to the lowest point of the male rotor chamber from over the cusp point and falling to the female rotor chamber. It accumulates at the bottom point. That is, the lowermost part of the male rotor chamber becomes an oil reservoir. When a certain amount of oil is accumulated in the oil reservoir, it is scooped up by the rotation of the male rotor to lubricate and cool the male rotor. Therefore, even when the liquid supply port is provided only on the female rotor chamber side, it is possible to prevent the liquid shortage on the male rotor chamber side.

A plurality of the liquid supply ports may be provided.

According to this configuration, uneven distribution of the liquid can be prevented by supplying the liquid to a plurality of places. Since the uneven distribution of the liquid can be prevented, the sealing performance by the liquid in the gap between the male and female rotors and the rotor casing is improved. The improvement in the sealing performance can reduce the amount of gas leaking to the adjacent tooth space on the suction side through the gap. When the gas leaks into the adjacent tooth space on the suction side, the leaked gas is compressed again, and a power loss occurs. Therefore, the compression efficiency can be improved by preventing the power loss.

The plurality of liquid supply ports may be further provided with a linear liquid supply pipe that is disposed on a straight line and connects the liquid feed ports disposed on a straight line.

According to this configuration, since the liquid supply pipe is linear, it is possible to prevent the shape of the liquid supply pipe from being complicated, and to reduce the number of steps for processing the liquid supply pipe. In addition, it is not necessary for all the liquid supply ports to be provided on a straight line, and in addition to the plurality of liquid supply ports disposed on a straight line, a liquid supply port disposed outside the straight line may exist.

In the rotation axis direction of the female rotor, the distance between the farthest points of the adjacent liquid supply ports may be smaller than the groove width of the female rotor.

According to this configuration, at least two liquid supply ports can be disposed in one tooth groove of the female rotor. Therefore, the lack of fluid in the tooth space can be suppressed. Therefore, the cooling performance and the sealing performance by a sufficient amount of liquid can be improved, and the compression efficiency can be improved.

In a cross section perpendicular to the rotation axis of the female rotor, a first virtual line segment connecting the rotation center point of the female rotor and the cusp point is defined, and the first virtual line segment is defined as the rotation center point of the female rotor A second virtual segment is defined around the first virtual angle rotated in a direction away from the cusp point, and the liquid supply port is a range excluding the range from the first virtual segment to the second virtual segment. May be provided.

According to this configuration, it is possible to prevent the liquid from being concentrated at the meshing position (generally coincident with the cusp point) of the male rotor and the female rotor. Generally, in a liquid-cooled screw compressor, the rotation of the male rotor and the female rotor tends to concentrate the liquid at the meshing position of the male rotor and the female rotor. If the liquid supply port is provided in the range from the first virtual line segment to the second virtual line segment, the liquid will be supplied near the meshing position between the male rotor and the female rotor, so that the liquid is concentrated at the meshing position As a result, the stirring loss of the liquid may be excessive and the compression efficiency may be deteriorated. However, in the above configuration, since the liquid supply port is provided at a certain distance from the meshing position (a range excluding the range from the first virtual line segment to the second virtual line segment), concentration of liquid can be prevented, and compression efficiency Can prevent the deterioration of Here, the first predetermined angle is an angle that can prevent concentration of the liquid at the meshing position, and is determined according to the shapes of the male rotor and the female rotor, the shape of the rotor casing, the type of liquid, and the like.

A first center line including the rotation center point of the male rotor and the rotation center point of the female rotor is defined in a cross section perpendicular to the rotation axis of the female rotor, and is orthogonal to the first center line. Defining a second center line passing through the rotation center point of the third virtual line segment rotated a second predetermined angle from the second center line in a direction away from the cusp point around the rotation center point of the female rotor The supply port may be provided in a range from the second virtual line segment to the third virtual line segment.

According to this configuration, it is possible to ensure sealing performance at the meshing position between the male rotor and the female rotor. If the liquid supply port is disposed at a position far away from the meshing position, the liquid may not be sufficiently supplied to the meshing position between the male rotor and the female rotor. In that case, gas leakage may occur at the meshing position between the male rotor and the female rotor, which may deteriorate the compression efficiency. However, in the above configuration, since the liquid supply port is provided in the range from the second virtual line segment to the third virtual line segment, the liquid can be sufficiently supplied to the meshing position. Therefore, the sealability at the meshing position can be secured, and the deterioration of the compression efficiency can be prevented. Here, the second predetermined angle is an angle that can prevent the liquid shortage at the meshing position, and is determined according to the shapes of the male and female rotors, the shape of the rotor casing, the type of liquid, and the like.

The liquid supply port may be provided on the second center line.

According to this configuration, it is possible to prevent the concentration and shortage of the liquid at the meshing position of the above-mentioned male rotor and female rotor. In other words, the second center line is a liquid feeding position which can prevent excess and deficiency of the liquid at the meshing position.

According to the present invention, in the liquid-cooled screw compressor, since the liquid supply port is provided so as to supply only the female rotor having a low rotational speed, overload due to high-speed stirring of the liquid on the male rotor side Since it can prevent, the stirring load of a liquid can be reduced.

A partial schematic configuration diagram of an oil-cooled screw compressor according to a first embodiment of the present invention Typical cross-sectional view of the rotor casing along the line II-II in FIG. 1 Typical cross-sectional view showing the position of the filler opening in the rotor casing Typical cross-sectional view showing the position of the filler opening in the rotor casing Sectional drawing which shows arrangement | positioning of the rotor casing of the oil-cooled-type screw compressor which concerns on 2nd Embodiment. Sectional drawing which shows arrangement | positioning of the rotor casing of the oil-cooled-type screw compressor which concerns on 3rd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the oil-cooling-type screw compressor which uses oil for the liquid supplied in a rotor casing is shown as what concerns on embodiment of this invention. Therefore, hereinafter, "oil" may be read as "liquid".

First Embodiment
FIG. 1 is a partial schematic configuration view of an oil-cooled screw compressor 1 according to a first embodiment of the present invention. Hereinafter, the oil-cooled screw compressor 1 is also referred to simply as the compressor 1. FIG. 1 shows a portion of the compressor 1 that relates particularly to a compression mechanism. The compressor 1 sucks in air from the outside, compresses it inside, and discharges it. The air discharged from the compressor 1 is supplied to the supply destination through piping (not shown).

The compressor 1 includes a rotor casing 10 and bearing

casings

20 and 21. In the present embodiment, the rotor casing 10 and the bearing

casings

20 and 21 are integrated. The rotor casing 10 is disposed between the two bearing

casings

20, 21. The rotor casing 10 internally defines a rotor chamber 30, and the two bearing

casings

20 and 21 respectively define bearing

chambers

33 and 34 therein. The rotor chamber 30 and the bearing chamber 33 are partitioned via the partition wall 11, and the rotor chamber 30 and the bearing chamber 34 are partitioned via the partition wall 12. The

partition walls

11 and 12 are both parts of the rotor casing 10.

In the rotor casing 10, a male rotor 50 and a female rotor 60 that meshes with the male rotor 50 and has more teeth than the male rotor 50 are disposed. That is, the screw rotor 40 is configured by the male rotor 50 and the female rotor 60. Although details are not illustrated, in the present embodiment, for example, the male rotor 50 has a four-tooth shape, and the female rotor 60 has a six-tooth shape.

FIG. 2 is a schematic cross-sectional view of the rotor casing 10 taken along line II-II of FIG. The rotor casing 10 defines a male rotor chamber 31 housing the male rotor 50 and a female rotor chamber 32 housing the female rotor 60. The rotor chamber 30 is a space in which the male rotor chamber 31 and the female rotor chamber 32 are combined. The rotor casing 10 has a shape in which two cylinders are connected on the side, in other words, the male rotor chamber 31 and the female rotor chamber 32 are both cylindrical spaces and are in communication with each other.

FIG. 2 is also a cross-sectional view of the female rotor 60 (see FIG. 1) as viewed from the rotational axis direction. In the present embodiment, the rotation axis of the female rotor 60 and the rotation axis of the male rotor 50 extend horizontally in parallel with each other, and the male rotor chamber 31 and the female rotor chamber 32 extend in the same direction. In the sectional view of FIG. 2, the male rotor chamber 31 and the female rotor chamber 32 are connected by two

cusp points

14a and 14b. As described above, although there are two

cusp points

14a and 14b, the term "cusp point 14" hereinafter indicates the cusp point 14b located on the lower side. The lowest point P <b> 3 of the male rotor chamber 31 is located below the cusp point 14 connecting the male rotor chamber 31 and the female rotor chamber 32. Thus, the oil reservoir Os can be provided in the male rotor chamber 31 as described later.

As shown in FIG. 1, from one end of the male rotor 50, a shaft member 51 serving as a rotation axis of the male rotor 50 extends. The shaft member 51 penetrates the partition wall 11 and extends from the male rotor chamber 31 to the bearing chamber 33, and is rotatably supported by the bearing 54 in the bearing chamber 33. Further, also from one end of the female rotor 60, a shaft member 61 serving as a rotation shaft of the female rotor 60 extends. The shaft member 61 penetrates the partition wall 11 and extends from the female rotor chamber 32 to the bearing chamber 33, and is rotatably supported by the bearing 63 in the bearing chamber 33.

From the other end of the male rotor 50, a shaft member 52 serving as a rotation shaft of the male rotor 50 extends. The shaft member 52 extends from the male rotor chamber 31 to the bearing chamber 34 through the partition wall 12 and is rotatably supported by the bearing 54 in the bearing chamber 34. Further, also from the other end of the female rotor 60, a shaft member 62 serving as a rotation shaft of the female rotor 60 extends. The shaft member 62 extends from the female rotor chamber 32 to the bearing chamber 34 through the partition wall 12 and is rotatably supported by the bearing 64 in the bearing chamber 34. In particular, the shaft member 52 of the male rotor 50 extends to a motor (not shown) and is mechanically connected to the motor. Accordingly, the male rotor 50 is rotationally driven by this motor, rotational power is transmitted from the male rotor 50 to the female rotor 60, and the male rotor 50 and the female rotor 60 mesh with each other and rotate to compress air. In FIG. 1, the right side is the suction side, and the left side is the discharge side. Therefore, when the male rotor 50 and the female rotor 60 rotate, in the rotor chamber 30, air is sucked from the bearing chamber 33 side and the air is discharged to the bearing chamber 34 side.

As shown in FIG. 2, the rotor casing 10 is provided with the fuel supply port 13 only on the side of the female rotor chamber 32. Three virtual line segments S1 to S3 are defined in order to define the detailed position of the fuel filler 13. A first virtual line segment S1 connecting the rotation center point P1 of the female rotor 60 and the cusp point 14 is defined. A second virtual line segment S2 is defined by rotating the first virtual line segment S1 around the rotation center point P1 of the female rotor 60 in the direction away from the cusp point 14 by a first predetermined angle θ1. Here, the first predetermined angle θ1 is an angle that can prevent the concentration of oil at the meshing position, depending on the shapes of the male rotor 50 and the female rotor 60, the shape of the rotor casing 10, the type of oil, etc. It becomes settled. Then, a first center line L1 including the rotation center point P2 of the male rotor 50 and the rotation center point P2 of the female rotor 60 is defined. The first center line L1 is a horizontal line. Further, a second center line L2 that is orthogonal to the first center line L1 and passes through the rotation center point P1 of the female rotor 60 is defined. Then, a third imaginary line segment S3 rotated about the rotation center point P1 of the female rotor 60 from the second center line L2 by the second predetermined angle θ2 in a direction away from the cusp point 14 is defined. Here, the second predetermined angle θ2 is an angle that can prevent oil shortage at the meshing position, and depends on the shapes of the male rotor 50 and the female rotor 60, the shape of the rotor casing 10, the type of oil, etc. It becomes settled.

The filler opening 13 is provided in the range excluding the range from the first virtual line segment S1 to the second virtual line segment S2, and more specifically, provided in the range from the second virtual line segment S2 to the third virtual line segment S3. Being preferred. More specifically, it is preferable that even part of the fuel filler 13 be provided in the range from the second virtual line segment S2 to the third virtual line segment S3. Here, it is preferable that the first predetermined angle θ1 be, for example, about 30 degrees or more. Further, the second predetermined angle θ2 is, for example, about 1⁄4 or less of the angle of one tooth of the female rotor 60, and in the present embodiment, since the six-tooth female rotor 60 is employed, 15 degrees It is preferable that it is below a grade. In the present embodiment, the fuel supply port 13 is provided in the range from the second virtual line segment S2 to the third virtual line segment S3, specifically, provided on the second center line L2.

FIG. 3 is a schematic cross-sectional view showing the position of the fuel supply port 13 in the rotor casing 10. In the present embodiment, a plurality of (four in FIG. 3) fuel ports 13 are linearly arranged. The four filler openings 13 are arranged at equal intervals, and in particular, the distance between the farthest points of the adjacent filler openings 13 (the distance between the farthest parts of the adjacent filler openings 13) is the teeth of the female rotor 60. It is smaller than the groove width D. That is, at least two filler openings 13 are disposed in one tooth groove.

FIG. 4 is a schematic cross-sectional view showing the position of the fuel filler in the rotor casing 10. As shown in FIG. The four fueling ports 13 are connected by one linear fueling pipe 15.

Below, the effect of the compressor 1 of this embodiment is demonstrated.

According to the present embodiment, since the female rotor 60 has fewer teeth than the male rotor 50, the rotational speed of the female rotor 60 can be made slower than the rotational speed of the male rotor 50. Furthermore, in the configuration of the present embodiment, since the oil supply port 13 is provided so as to supply only the female rotor 60 having a low rotational speed, it is possible to prevent an overload due to high-speed stirring of oil on the male rotor 50 side. Therefore, since the power loss accompanying agitation of oil can be reduced, the compression efficiency can be improved. The oil supplied to the female rotor chamber 32 is also supplied to the male rotor chamber 31 as the female rotor 60 meshes with the male rotor 50. Since the lowermost point of the male rotor chamber 31 is located below the cusp point 14, oil that has flowed down to the lowermost point P 3 of the male rotor chamber 31 can be prevented from passing over the cusp point 14 and flowing down to the female rotor chamber 32. , The lowermost point P3 of the male rotor chamber 31. That is, the lowermost portion of the male rotor chamber 31 becomes an oil reservoir Os. When a certain amount of oil is accumulated in the oil reservoir Os, the oil is scooped up by the rotation of the male rotor 50 to lubricate and cool the male rotor 50. Therefore, even with the configuration in which the oil supply port 13 is provided only on the female rotor chamber 32 side, it is possible to prevent the shortage of oil on the male rotor chamber 31 side.

Further, according to the present embodiment, as shown in FIG. 3, uneven distribution of oil can be prevented by providing a plurality of fueling ports 13 and supplying fuel to a plurality of places. Since uneven distribution of oil can be prevented, the sealing performance with oil in the gap between the male rotor 50 and the female rotor 60 and the rotor casing 10 is improved. The improvement of the sealing performance can reduce the amount of gas leaking to the adjacent tooth space on the suction side (right side in FIG. 1) through the gap. When the gas leaks into the adjacent tooth space on the suction side, the leaked gas is compressed again, and a power loss occurs. Therefore, the compression efficiency can be improved by preventing the power loss.

Further, according to the present embodiment, as shown in FIG. 4, since the oil supply pipe 15 is linear, it is possible to prevent the shape of the oil supply pipe 15 from being complicated and to reduce the number of steps for processing the oil supply pipe 15. . It is not necessary that all of the filler openings 13 be provided on a straight line, and in addition to the plurality of filler openings disposed on a straight line, the filler openings 13 disposed outside the straight line may be present.

Further, according to the present embodiment, as shown in FIG. 3, at least two filler openings 13 can be disposed in one tooth groove of the female rotor 60. Therefore, the oil shortage in the tooth space can be suppressed. Therefore, the cooling performance and the sealing performance by a sufficient amount of oil can be improved, and the compression efficiency can be improved.

Further, according to the present embodiment, as shown in FIG. 2, since the position of the fuel filler 13 is defined, the oil is concentrated at the meshing position of the male rotor 50 and the female rotor 60 (generally coincides with the cusp point 14). Can be prevented. In general, in the oil-cooled screw compressor 1, the rotation of the male rotor 50 and the female rotor 60 tends to concentrate the oil at the meshing position between the male rotor 50 and the female rotor 60. If the fuel supply port 13 is provided in the range from the first virtual line segment S1 to the second virtual line segment S2, the oil is engaged near the meshing position between the male rotor 50 and the female rotor 60. By concentrating on the above, there is a possibility that the loss of stirring of the oil will be excessive and the compression efficiency will deteriorate. However, in the configuration of the present embodiment, since the fuel supply port 13 is provided at a position distant from the meshing position by a certain degree (a range excluding the range from the first virtual line segment S1 to the second virtual line segment S2) Can be prevented, and the deterioration of the compression efficiency can be prevented.

Further, according to the present embodiment, as shown in FIG. 2, the position of the fuel filler 13 is defined, so that the sealing performance at the meshing position between the male rotor 50 and the female rotor 60 can be secured. If the fuel supply port 13 is disposed at a position far away from the meshing position, there is a possibility that oil can not be sufficiently supplied to the meshing position between the male rotor 50 and the female rotor 60. In that case, gas leakage may occur at the meshing position between the male rotor 50 and the female rotor 60, and the compression efficiency may be degraded. However, in the configuration of the present embodiment, since the fuel supply port 13 is provided in the range from the second virtual line segment S2 to the third virtual line segment S3, oil can be sufficiently supplied to the meshing position. Therefore, the sealability at the meshing position can be secured, and the deterioration of the compression efficiency can be prevented.

Further, according to the present embodiment, concentration and shortage of oil at the meshing position between the male rotor 50 and the female rotor 60 can be prevented. In other words, the second center line L2 is a refueling position that can prevent excess and deficiency of oil at the meshing position.

Second Embodiment
FIG. 5 is a cross-sectional view of the rotor casing 10 of the compressor 1 according to the second embodiment, which corresponds to FIG. 2 of the first embodiment. In the compressor 1 of the present embodiment, the rotor casing 10 is disposed in a state where the first center line L1 is inclined from the horizontal line HL. The configuration other than this is the same as the configuration of the compressor 1 according to the first embodiment of FIG. Therefore, the same parts as those in the configuration shown in FIG.

In the present embodiment, the rotation axis CL1 of the female rotor 60 and the rotation axis CL2 of the male rotor 50 are not disposed in the horizontal plane, and the rotation axis CL1 of the female rotor 60 is lower than the rotation axis CL2 of the male rotor 50. Is located in Specifically, the first center line L1 is, for example, about 30 degrees from the horizontal line HL. Therefore, the female rotor chamber 32 is disposed below the male rotor chamber 31.

Also in this embodiment, the lowest point P3 of the male rotor chamber 31 is located below the cusp point 14 connecting the male rotor chamber 31 and the female rotor chamber 32, as in the first embodiment. Therefore, the oil reservoir Os is formed in the lower part of the male rotor chamber 31 as in the first embodiment.

Third Embodiment
FIG. 6 is a cross-sectional view of the rotor casing 10 of the compressor 1 according to the third embodiment, which corresponds to FIG. 2 of the first embodiment. In the compressor 1 according to the present embodiment, the rotor casing 10 is disposed in a state where the first center line L1 is vertical. The configuration other than this is the same as the configuration of the compressor 1 according to the first embodiment of FIG. Therefore, the same parts as those in the configuration shown in FIG.

In the present embodiment, the rotation axis CL1 of the female rotor 60 and the rotation axis CL2 of the male rotor 50 are not disposed in the horizontal plane, and the rotation axis CL2 of the male rotor 50 is directly below the rotation axis CL1 of the female rotor 60. It is arranged. Therefore, the entire male rotor chamber 31 is disposed below the entire female rotor chamber 32.

Also in the present embodiment, the lowermost point P3 of the male rotor chamber 31 is located below the cusp point 14 connecting the male rotor chamber 31 and the female rotor chamber 32, as in the first and second embodiments. There is. Therefore, the oil reservoir Os is formed in the lower part of the male rotor chamber 31 as in the first embodiment.

As mentioned above, although each concrete embodiment of the present invention was described, the present invention is not limited to the above-mentioned form, and can be variously changed and carried out within the scope of the present invention.

As described above, according to the embodiment of the present invention, the oil-cooled compressor using oil for the liquid supplied into the rotor casing has been shown. However, the present invention is applicable to liquid-cooled compressors other than oil-cooled compressors. For example, the present invention can also be applied to a water jet compressor using water as the liquid supplied into the rotor casing.

1 Compressor (oil-cooled screw compressor)
DESCRIPTION OF SYMBOLS 10

Rotor casing

11, 12 Partition wall 13 Refueling

port

14, 14a, 14b Casp point 15

Oil supply piping

20, 21 Bearing casing 30 Rotor chamber 31 Male rotor chamber 32

Female rotor chamber

33, 34 Bearing chamber 40 Screw rotor 50

Male rotor

51, 52

shaft member

53, 54 bearing 60

female rotor

61, 62

shaft member

63, 64 bearing

Claims

Male rotor,
A female rotor that meshes with the male rotor and has more teeth than the male rotor;
A rotor casing defining a male rotor chamber accommodating the male rotor and a female rotor chamber accommodating the female rotor;
And a liquid supply port provided only on the female rotor chamber side of the rotor casing,
In a cross section perpendicular to the rotation axis of the female rotor, a lowermost point of the male rotor chamber is located lower than a cusp point located at the lowest position connecting the male rotor chamber and the female rotor chamber. Cold screw compressor.
The liquid-cooled screw compressor according to claim 1, wherein a plurality of the liquid supply ports are provided.
The plurality of liquid supply ports are disposed on a straight line,
The liquid-cooled screw compressor according to claim 2, further comprising a linear liquid supply pipe connecting the liquid supply ports disposed on a straight line.
The liquid-cooled screw compressor according to claim 3, wherein a distance between the farthest points of the adjacent liquid supply ports in the rotational axis direction of the female rotor is smaller than a width of a groove of the female rotor.
In a cross section perpendicular to the rotation axis of the female rotor:
Defining a first virtual segment connecting the rotation center point of the female rotor and the cusp point;
Defining a second virtual line segment obtained by rotating the first virtual line segment by a first predetermined angle around the rotation center point of the female rotor in a direction away from the cusp point;
The liquid-cooling screw compression according to any one of claims 1 to 4, wherein the liquid supply port is provided in a range excluding the range from the first virtual line segment to the second virtual line segment. Machine.
In a cross section perpendicular to the rotation axis of the female rotor:
Defining a first center line including a rotation center point of the male rotor and a rotation center point of the female rotor;
Defining a second center line orthogonal to the first center line and passing through the rotation center point of the female rotor;
Defining a third imaginary line segment rotated a second predetermined angle from the second center line in a direction away from the cusp point around the rotation center point of the female rotor;
The liquid-cooled screw compressor according to claim 5, wherein the liquid supply port is provided in a range from the second virtual line segment to the third virtual line segment.
The liquid-cooled screw compressor according to claim 6, wherein the liquid supply port is provided on the second center line.