WO2023112424A1

WO2023112424A1 - Liquid supply type screw compressor

Info

Publication number: WO2023112424A1
Application number: PCT/JP2022/036623
Authority: WO
Inventors: 紘太郎千葉; 茂幸頼金; 謙次森田; 雄太梶江
Original assignee: 株式会社日立産機システム
Priority date: 2021-12-13
Filing date: 2022-09-30
Publication date: 2023-06-22
Also published as: JP2023087275A

Abstract

Provided is a liquid supply type screw compressor capable of saving energy by reducing the shaft power required for stirring liquid.　The liquid supply type screw compressor has: a male rotor side bore 22A in which a teeth part 13A of a male rotor 11A is housed; a female rotor side bore 22B in which a teeth part 13B of a female rotor 11B is housed; a low pressure side cusp 23 and a high pressure side cusp 24 that are boundaries between a wall surface of the male rotor side bore 22A and a wall surface of the female rotor side bore 22B; and a pocket 29 located adjacent to the low pressure side cusp 23 in the rotor axial direction, and formed to be depressed outward in the rotor radial direction relative to the wall surface of the male rotor side bore 22A and the wall surface of the female rotor side bore 22B. The pocket 29 is formed by inclined surfaces 30A, 30B. The inclined surface 30A extends from the wall surface of the male rotor side bore 22A beyond a virtual plane C1 including the low pressure side cusp 23 and the high pressure side cusp 24.

Description

Feed screw compressor

The present invention relates to a feed-type screw compressor that compresses gas while supplying liquid to a working chamber.

A liquid feeding type screw compressor compresses gas (eg air) while supplying liquid (eg oil) to the working chamber. The purposes of the liquid supply include gas cooling during the compression stroke, working chamber gap sealing, and rotor lubrication.

The feed type screw compressor includes, for example, a male rotor and a female rotor that rotate while meshing with each other, a male rotor side bore that accommodates the teeth of the male rotor, a female rotor side bore that accommodates the teeth of the female rotor, A low-pressure side cusp and a high-pressure side cusp that are boundaries between the wall surface of the male rotor side bore and the wall surface of the female rotor side bore, the male rotor side working chamber that is formed in the tooth groove of the male rotor and compresses gas, and the female rotor. and a female rotor side working chamber for compressing gas.

The volumes of the male rotor side working chamber and the female rotor side working chamber change while moving from one side to the other side in the axial direction of the rotor as the male rotor and the female rotor rotate. As a result, an intake stroke for sucking gas through the intake passage, a compression stroke for compressing the gas, and a discharge stroke for discharging the compressed gas through the discharge passage are sequentially performed.

In the above-described feed type screw compressor, the jet flow flows from the high-pressure side working chamber to the low-pressure side working chamber through the meshing portion between the male rotor and the female rotor (in other words, the gap between the male rotor and the female rotor). occurs. Depending on the structure of the compressor, the liquid contained in the compressed gas may turn into high-temperature mist and blow out into the suction flow path.

Therefore, the feed-type screw compressor of Patent Document 1 has ribs arranged in the suction flow path and pockets formed by the ribs. The pocket is positioned adjacent to the low pressure side cusp in the axial direction of the rotor, and is recessed radially outward of the wall surface of the male rotor side bore and the wall surface of the female rotor side bore. The ribs and pockets prevent the liquid contained in the compressed gas from being spouted into the suction flow path.

JP 2010-174830 A

However, the conventional technology has room for improvement as follows.

The rib of Patent Document 1 has a line-symmetrical structure about a first imaginary plane including the low pressure side cusp and the high pressure side cusp. Therefore, the pocket of Patent Document 1 extends from the wall surface of the male rotor side bore so as not to exceed the first imaginary plane, and the farther away from the wall surface of the male rotor side bore, the axial center of the male rotor and the female rotor. A first slanted surface slanted away from a second imaginary plane including the axial center of the female rotor, and a wall surface of the female rotor side bore extending so as not to exceed the first imaginary plane, the female rotor and a second slanted surface that is slanted so as to be farther away from the second imaginary plane as it is further away from the wall surface of the side bore.

The liquid ejected from the male rotor side working chamber and the female rotor side working chamber passes through the pocket and flows into the male rotor side working chamber and the female rotor side working chamber again. According to the pocket structure described above, the distribution ratio of the liquid flowing from the pocket into the male rotor side working chamber is substantially the same as the distribution ratio of the liquid flowing from the pocket into the female rotor side working chamber.

However, since the male rotor generally has a larger outer diameter than the female rotor, its rotational speed is higher than that of the female rotor. Therefore, the liquid that has flowed into the male rotor side working chamber is agitated at a higher speed than the liquid that has flowed into the female rotor side working chamber. Therefore, if the distribution ratio of the liquid flowing into the working chamber on the female rotor side from the pocket is increased and the distribution ratio of the liquid flowing into the working chamber on the male rotor side from the pocket is decreased, the shaft power required for stirring the liquid can be reduced. It is possible to connect and save energy.

The present invention has been made in view of the above matters, and one of its objectives is to reduce the shaft power required for stirring liquids to save energy.

In order to solve the above problems, the configuration described in the claims is applied. The present invention includes a plurality of means for solving the above problems. One example is a male rotor and a female rotor that rotate while meshing with each other, and a male rotor side that accommodates the teeth of the male rotor. a bore, a female rotor-side bore that accommodates the teeth of the female rotor, a low-pressure side cusp and a high-pressure side cusp that are boundary lines between the wall surface of the male rotor-side bore and the wall surface of the female rotor-side bore, and the male rotor. A male rotor side working chamber formed in the tooth groove of the rotor for compressing the gas, a female rotor side working chamber formed in the tooth groove of the female rotor for compressing the gas, the male rotor side working chamber and the female rotor In a liquid feed type screw compressor having a liquid feed nozzle for supplying liquid to a side working chamber, the nozzle is positioned adjacent to the low-pressure side cusp in the rotor axial direction, and includes a wall surface of the male rotor side bore and the female rotor. It further has a pocket formed so as to be recessed outward in the rotor radial direction from the wall surface of the side bore. extending beyond the plane, and inclined to be farther away from the second imaginary plane including the axial center of the male rotor and the axial center of the female rotor as the wall surface of the male rotor side bore is further away. and a first inclined surface that extends from the wall surface of the female rotor-side bore so as not to exceed the first virtual plane, and the farther away from the wall surface of the female rotor-side bore, the more it lies on the second virtual plane. and a second slanted surface slanted away from the slanted surface.

According to the present invention, it is possible to save energy by reducing the shaft power required for stirring the liquid.

In addition, problems, configurations and effects other than the above will be clarified by the following explanation.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic showing the structure of the feed type screw compressor in the 1st Embodiment of this invention. 1 is an axial sectional view showing the structure of a compressor main body in a first embodiment of the invention; FIG. 1 is an axial sectional view showing the structure of a compressor main body in a first embodiment of the invention; FIG. 1 is a radial cross-sectional view showing the structure of a compressor main body according to a first embodiment of the present invention; FIG. FIG. 6 is an axial cross-sectional view showing the structure of a compressor body in a second embodiment of the present invention; FIG. 6 is a radial cross-sectional view showing the structure of a compressor body according to a second embodiment of the present invention; FIG. 5 is an axial cross-sectional view showing the structure of a compressor main body in a modified example of the present invention;

A first embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. FIG. 1 is a schematic diagram showing the configuration of a feed screw compressor in this embodiment. 2 and 3 are axial sectional views showing the structure of the compressor main body in this embodiment. FIG. 4 is a radial cross-sectional view showing the structure of the compressor main body in this embodiment. 2 corresponds to a cross-sectional view along section II-II in FIG. 4, and FIG. 3 corresponds to a cross-sectional view along section III-III in FIG. FIG. 4 corresponds to a cross-sectional view along section IV--IV in FIG. 2 or FIG.

The screw compressor of this embodiment includes a motor 1, a compressor main body 2 that is driven by the motor 1 and compresses gas (for example, air), compressed gas discharged from the compressor main body 2, and liquid contained therein ( and a liquid pipe 4 for supplying the liquid separated by the gas-liquid separator 3 to the working chamber of the compressor main body 2 . The liquid pipe 4 is provided with a cooler 5 for cooling the liquid, a filter 6 for removing impurities in the liquid, and the like.

The compressor main body 2 includes a male rotor 11A, a female rotor 11B, and a casing 12 that houses the male rotor 11A and the female rotor 11B.

The male rotor 11A includes a tooth portion 13A having a plurality (four in this embodiment) of spirally extending teeth, and a suction side shaft connected to one axial side (left side in FIG. 2) of the tooth portion 13A. and a discharge-side shaft portion 15 connected to the other axial side (right side in FIG. 2) of the tooth portion 13A. A suction side shaft portion 14 of the male rotor 11A is rotatably supported by a suction side bearing 16, and a discharge side shaft portion 15 of the male rotor 11A is rotatably supported by a discharge side bearing 17. As shown in FIG.

Similarly, the female rotor 11B includes a tooth portion 13B having a plurality (six in this embodiment) of spirally extending teeth, and a suction side shaft portion (Fig. (not shown) and a discharge-side shaft portion (not shown) connected to the other axial side of the tooth portion 13B. A suction side shaft portion of the female rotor 11B is rotatably supported by a suction side bearing (not shown), and a discharge side shaft portion of the female rotor 11B is rotatably supported by a discharge side bearing (not shown).

The suction-side shaft portion 14 of the male rotor 11A passes through the casing 12 and is connected to the rotating shaft of the motor 1. The driving of the motor 1 causes the male rotor 11A to rotate, and the meshing of the teeth 13A of the male rotor 11A and the teeth 13B of the female rotor 11B causes the female rotor 11B to also rotate.

The casing 12 includes a main casing 18, a suction side casing 19 connected to one axial side (left side in FIG. 2) of the main casing 18, and a suction side casing 19 connected to the other axial side (right side in FIG. 2) of the main casing 18. and a discharge side casing 20.

The main casing 18 includes a male rotor side bore 22A that accommodates the tooth portion 13A of the male rotor 11A and forms a male rotor side working chamber 21A in the tooth groove thereof, and a tooth portion 13B of the female rotor 11B that accommodates the tooth groove. and a female rotor side bore 22B forming a female rotor side working chamber 21B. The

bores

22A, 22B partially overlap each other and have a low pressure side cusp 23 and a high pressure side cusp 24 as their wall boundaries.

The volumes of the male rotor side working chamber 21A and the female rotor side working chamber 21B change while moving from one side to the other side in the rotor axial direction as the male rotor 11A and the female rotor 11B rotate. As a result, an intake stroke for sucking gas through the intake passage 25, a compression stroke for compressing the gas, and a discharge stroke for discharging the compressed gas through the discharge passage 26 are sequentially performed. The suction passage 25 of this embodiment is arranged so as to overlap with the toothed portion 13A of the male rotor 11A and the toothed portion 13B of the female rotor 11B when viewed from the rotor radial direction, and extends in the rotor radial direction.

The main casing 18 has liquid supply nozzles 27 that supply liquid to the male rotor side working chamber 21A and the female rotor side working chamber 21B. The purposes of the liquid supply include gas cooling during the compression stroke, working chamber gap sealing, and rotor lubrication.

In the compressor main body 2 described above, the air flows from the high-pressure side working chamber to the low-pressure side working chamber via the meshing portion between the male rotor 11A and the female rotor 11B (in other words, the gap between the male rotor 11A and the female rotor 11B). A jet flow is produced. Then, depending on the structure of the compressor main body 2 , the liquid contained in the compressed gas may become high-temperature mist and blow out into the suction flow path 25 .

Therefore, the compressor body 2 of the present embodiment is formed by the ribs 28 arranged in the suction passage 25 and extending in the axial direction of the rotor (in other words, the ribs 28 do not communicate directly with the suction passage 25). and a pocket 29 formed as follows. The pocket 29 is positioned adjacent to the low-pressure side cusp 23 in the axial direction of the rotor, and is recessed outward in the rotor radial direction (upper side in FIG. 4) from the wall surface of the male rotor side bore 22A and the wall surface of the female rotor side bore 22B. formed to fit. In addition, the pocket 29 is formed on a width H1 of the meshing portion between the male rotor 11A and the female rotor 11B (more specifically, on a straight line perpendicular to the axial center O1 of the male rotor 11A and the axial center O2 of the female rotor 11B). distance between the position where the tooth tip of the female rotor 11B passes and the position where the tooth tip of the female rotor 11B passes) and smaller than the width H2 between the axial center O1 of the male rotor 11A and the axial center O2 of the female rotor 11B. formed. The ribs 28 and the pockets 29 prevent the liquid contained in the compressed gas from spouting into the suction flow path 25 .

Here, as the most significant feature of this embodiment, the rib 28 has a structure that is not line-symmetrical about the imaginary plane C1 including the low pressure side cusp 23 and the high pressure side cusp 24 as the center. The pocket 29 is formed by the

inclined surfaces

30A and 30B of the rib 28. As shown in FIG. The inclined surface 30A of the rib 28 extends from the wall surface of the male-rotor-side bore 22A so as to exceed the imaginary plane C1. 11B so as to be greatly separated from the imaginary plane C2 including the axis O2 of 11B. The inclined surface 30B of the rib 28 extends from the wall surface of the female rotor-side bore 22B so as not to exceed the imaginary plane C2, and the farther away from the wall surface of the female rotor-side bore 22B, the farther away from the imaginary plane C2. inclined to Therefore, the boundary between the inclined surface 30A and the inclined surface 30B of the rib 28 (in other words, the bottom of the pocket 29) is positioned closer to the axial center O2 of the female rotor 11B than the imaginary plane C1.

With the structure of the pocket 29 described above, the following effects can be obtained. Most of the lubricating oil ejected from the male rotor side working chamber 21A and the female rotor side working chamber 21B and flowed into the pockets 29 collides with the

inclined surfaces

30A or 30B of the ribs 28 due to inertial force, 30B and gather near the boundary between the

inclined surfaces

30A and 30B. After that, most of the lubricating oil collected near the boundary between the

inclined surfaces

30A and 30B of the rib 28 flows into the female rotor working chamber 21B due to its own weight. Therefore, the distribution ratio of liquid flowing from the pocket 29 into the female rotor side working chamber 21B can be increased, and the distribution ratio of the liquid flowing from the pocket 29 into the male rotor side working chamber 21A can be decreased. Here, the liquid that has flowed into the male rotor side working chamber 21A is agitated at a higher speed than the liquid that has flowed into the female rotor side working chamber 21B. Therefore, it is possible to save energy by reducing the shaft power required for stirring the liquid.

A second embodiment of the present invention will be described with reference to FIGS. 5 and 6. FIG. FIG. 5 is an axial cross-sectional view showing the structure of the compressor main body in this embodiment. FIG. 6 is a radial cross-sectional view showing the structure of the compressor main body in this embodiment. 5 corresponds to a cross-sectional view taken along line VV in FIG. 6, and FIG. 6 corresponds to a cross-sectional view taken along line VI-VI in FIG. In addition, in this embodiment, the same code|symbol is attached|subjected to the part equivalent to 1st Embodiment, and description is abbreviate|omitted suitably.

The suction passage 25A of this embodiment is arranged so as not to overlap the toothed portion 13A of the male rotor 11A and the toothed portion 13B of the female rotor 11B when viewed from the rotor radial direction, and extends in the rotor radial direction. Unlike the pocket 29 of the first embodiment, the pocket 29A of this embodiment is formed so as to directly communicate with the suction flow path 25A.

Like the pocket 29 of the first embodiment, the pocket 29A of the present embodiment is positioned adjacent to the low-pressure side cusp 23 in the axial direction of the rotor. It is formed so as to be recessed outward in the rotor radial direction (upper side in FIG. 6) from the wall surface. Further, it is formed to be larger than the width H1 of the meshing portion between the male rotor 11A and the female rotor 11B and smaller than the width H2 between the axial center O1 of the male rotor 11A and the axial center O2 of the female rotor 11B.

The pocket 29A of this embodiment is formed of

inclined surfaces

30A and 30B. The inclined surface 30A extends from the wall surface of the male rotor side bore 22A so as to exceed the virtual plane C1, and is inclined to be farther away from the virtual plane C2 as the distance from the wall surface of the male rotor side bore 22A increases. . The inclined surface 30B extends from the wall surface of the female rotor side bore 22B so as not to exceed the imaginary plane C2, and is inclined so as to be farther away from the imaginary plane C2 as the distance from the wall surface of the female rotor side bore 22B increases. there is Therefore, the boundary between the inclined surface 30A and the inclined surface 30B (in other words, the bottom of the pocket 29A) is positioned closer to the axial center O2 of the female rotor 11B than the imaginary plane C1.

Also in this embodiment configured as described above, similarly to the first embodiment, it is possible to reduce the axial power required for stirring the liquid and to save energy.

In the second embodiment, when the pocket 29A is formed so as to directly communicate with the suction flow path 25A (that is, the male rotor side working chamber 21A and the female rotor side working chamber 21B are connected to the suction flow path 25A and The case where gas is sucked through the pocket 29A) has been described as an example, but the present invention is not limited to this. For example, as in the modification shown in FIG. 7, the pocket 29A may be formed by a partition wall 31 extending in the radial direction of the rotor so as not to directly communicate with the suction flow path 25A. As a result, the liquid contained in the compressed gas may be prevented from spouting into the suction flow path 25A.

In addition, although not specifically described in the first and second embodiments, the inclined surface 30A is composed of at least one flat surface, at least one curved surface, or a combination thereof. It is good if it is. Also, the inclined surface 30B may be composed of at least one flat surface, at least one curved surface, or a combination thereof.

11A... male rotor, 11B... female rotor, 13A, 13B... teeth, 21A... male rotor side working chamber, 21B... female rotor side working chamber, 22A... male rotor side bore, 22B... female rotor side bore, 23... low pressure Side cusp 24 High-

pressure side cusp

25, 25A Suction channel 27

Liquid supply nozzle

29,

29A Pocket

30A, 30B Inclined surface

Claims

a male rotor and a female rotor that rotate while meshing with each other;
a male rotor-side bore that accommodates the teeth of the male rotor;
a female rotor-side bore that accommodates the teeth of the female rotor;
a low pressure side cusp and a high pressure side cusp, which are boundary lines between the wall surface of the male rotor side bore and the wall surface of the female rotor side bore;
a male rotor side working chamber formed in the tooth groove of the male rotor for compressing gas;
a female rotor side working chamber formed in the tooth groove of the female rotor for compressing gas;
In a liquid feed type screw compressor having a liquid feed nozzle that supplies liquid to the male rotor side working chamber and the female rotor side working chamber,
a pocket positioned adjacent to the low pressure side cusp in the rotor axial direction and recessed outward in the rotor radial direction from the wall surface of the male rotor side bore and the wall surface of the female rotor side bore;
The pocket is
The shaft of the male rotor extends from the wall surface of the male rotor side bore so as to exceed a first imaginary plane including the low pressure side cusp and the high pressure side cusp, and the farther away from the wall surface of the male rotor side bore, the shaft of the male rotor. a first slanted surface slanted away from a second imaginary plane including the center and the axial center of the female rotor;
Extends from the wall surface of the female rotor side bore so as not to exceed the first virtual plane, and is inclined to be farther away from the second virtual plane as the distance from the wall surface of the female rotor side bore increases. A feed screw compressor characterized by being formed with a second slanted surface.
In the feed screw compressor according to claim 1,
The pocket is formed so as to be larger than the width of the meshing portion of the male rotor and the female rotor and smaller than the width between the axial center of the male rotor and the axial center of the female rotor. feed type screw compressor.
In the feed screw compressor according to claim 1,
A feed type screw compressor, wherein the pocket is formed so as not to directly communicate with a suction passage communicating with the male rotor side working chamber and the female rotor side working chamber.