JPH10184571A - Inverter controlled two-stage screw compressor - Google Patents

Abstract

(57) [Problem] To provide an inverter-controlled two-stage screw compressor capable of securing a sufficient motor cooling capacity even if the rotation speed of a motor is reduced and of reducing the size of the entire compressor. SOLUTION: A low-pressure stage compression unit 5 and a high-pressure stage compression unit 6 are connected via an intercooler 8, and an aftercooler 10 is connected to the discharge side of the high-pressure stage compression unit 6. In an inverter-controlled two-stage screw compressor 1 that drives 5, 6 with an inverter-controlled AC motor, the AC motor is a double-axis motor 4,
The low-pressure stage and high-pressure stage compression units 5 and 6 are connected to both ends of the drive shaft 2 of the double shaft motor 4, respectively.
The intercooler 8 is located at the low-pressure stage cooling fan 11 and the aftercooler 10 is located at the high-pressure stage cooling fan 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an inverter control 2
The present invention relates to a stage screw compressor.

[0002]

2. Description of the Related Art In a two-stage screw compressor, a low-pressure stage compressor and a high-pressure stage compressor are connected via an intercooler, and an aftercooler is connected to the discharge side of the high-pressure stage compressor. The stage compression section is driven by a motor.

[0003] The motor has a single rotating shaft, and the rotating shaft is connected to a low-pressure stage compression unit and a high-pressure stage compression unit to drive each compression unit. Further, a cooling fan is connected to the tip of the rotating shaft, and blows air to an intercooler connected to the discharge side of the low-pressure stage compression section and an aftercooler connected to the discharge side of the high-pressure stage compression section, and the respective coolers It is designed to cool down.

[0004]

However, since the intercooler and the aftercooler are arranged at a position facing one cooling fan connected to the rotating shaft of the motor for cooling, it is necessary to obtain sufficient cooling air. In addition, when the motor is operated while adjusting the rotation speed as an inverter motor, the motor cooling capability is lowered along with the rotation speed, and the rotation speed of the motor cannot be sufficiently reduced. .

In addition, since the intercooler and the aftercooler are arranged side by side in front of one cooling fan, there is a problem that the whole compressor becomes large.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems, to provide a sufficient motor cooling capacity even if the number of revolutions of the motor is reduced, and to reduce the size of the compressor as a whole. It is to provide a stage screw compressor.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is to connect a low-pressure stage compression section and a high-pressure stage compression section via an intercooler, and to provide an aftercooler at the discharge side of the high-pressure stage compression section. In an inverter-controlled two-stage screw compressor that drives these low-pressure and high-pressure stage compressors with an inverter-controlled AC motor, the AC motor is a double-shaft motor, and both ends of the drive shaft of the double-shaft motor are The low-pressure stage and high-pressure stage compression units are connected and a cooling fan is connected to the low-pressure stage cooling fan. The intercooler is located at the low-pressure stage cooling fan, and the aftercooler is located at the high-pressure stage cooling fan.

In addition, a casing is provided which surrounds the two-shaft motor and the two compression parts and has openings at both ends located at the two cooling fans, and the suction flow of the cooling fan flows through the two-shaft motor on the side surface of the casing. An air suction port may be formed so as to be discharged from the opening.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIGS. 1 and 3, an inverter-controlled two-stage screw compressor 1 (hereinafter referred to as a compressor 1).
A two-shaft motor 4 composed of an AC motor having both ends of the drive shaft 2 extending from the motor body 3, and a low-pressure stage compressor fixed on the two-shaft motor 4 and connected to one end of the drive shaft 2. 5, a high-pressure compression unit 6 fixed on the two-shaft motor 4 and connected to the other end of the drive shaft 2, a discharge side of the low-pressure compression unit 5 and a suction side of the high-pressure compression unit 6. A connection pipe 7 to be connected, an intercooler 8 connected in the middle of the connection pipe 7, and a discharge pipe 9 connected to the discharge side of the high-pressure stage compression unit 6
And an aftercooler 10 connected in the middle of the discharge pipe 9
And a first cooling fan 11 and a second cooling fan 12 connected to both ends of the drive shaft 2.

The low-pressure stage compression section 5 is a screw-type compression section. As shown in FIGS. 1 to 5, the first transmission shaft 13 protrudes from one end of the motor main body 3, and the first transmission The shaft 13 is fixed so as to be positioned obliquely above the drive shaft 2. The first transmission shaft 13 is provided with a first pulley 14, and the first pulley 14 is connected to a second pulley 15 provided at one end of the drive shaft 2 via a belt 16.

The high-pressure stage compression section 6 is a screw-type compression section. The second transmission shaft 17 protrudes from the other end of the motor body 3, and the second transmission shaft 17 is positioned obliquely above the drive shaft 2. It is fixed to be located. The second transmission shaft 17 is provided with a third pulley 18, and the third pulley 1
8 is a fourth pulley 1 provided at the other end of the drive shaft 2.
9 via a belt 20.

The low-pressure stage compression section 5 and the high-pressure stage compression section 6
Are fixed on the two-shaft motor 4 so as to be staggered in plan view, so that the space on the two-shaft motor 4 is effectively used to make the overall size of the compressor 1 compact.

A suction filter 22 is connected to the suction side of the low-pressure stage compression section 5 via a suction pipe 21, so that outside air is sucked into the low-pressure stage compression section 5 through the suction filter 22. ing.

The intercooler 8 is for cooling the compressed air discharged from the low-pressure stage compression section 5, and is disposed at a position facing the first cooling fan 11.

The aftercooler 10 includes a high-pressure stage compression unit 6.
For cooling the compressed air discharged from the
It is arranged at a position facing the cooling fan 12.

The compressor 1 is surrounded by a casing 23 for dividing the flow of air. The casing 23 surrounds the two-axis motor 4 and the two compression parts 5 and 6, and has openings 24 and 25 located at both ends of the first cooling fan 11 and the second cooling fan 12, respectively. Air inlet 26.

The openings 24 and 25 are formed so as to surround the outer peripheral sides of the first cooling fan 11 and the second cooling fan 12, and discharge the air in the casing 23 toward the intercooler 8 and the after cooler 10. It has become.

The air suction port 26 is formed at a position facing the motor body 3, and is provided with the first cooling fan 11 and the second cooling fan 11.
The suction flow of the cooling fan 12 is formed so as to pass around the motor body 3 and then to be discharged from the openings 24 and 25.

Next, the operation will be described.

When the two-shaft motor 4 is driven, the second pulley 15 and the fourth pulley 19 are rotated with the rotation of the drive shaft 2, and the first cooling fan 11 and the second cooling fan 12 are rotated.

The rotation of the second pulley 15 is transmitted to the first transmission shaft 13 via the belt 16 and the first pulley 14 to drive the low-pressure stage compression unit 5, and the rotation of the fourth pulley 19. Is transmitted to the second transmission shaft 17 via the belt 20 and the third pulley 18, and the high-pressure stage compression unit 6 is driven.

When the low-pressure stage compression section 5 and the high-pressure stage compression section 6 are driven in this manner, the outside air is sucked into the low-pressure stage compression section 5 through the suction filter 22 and the suction pipe 21 and reaches a predetermined pressure. After being compressed, it is discharged to the connection pipe 7. The compressed air discharged to the connection pipe 7 enters the intercooler 8 cooled by the air from the first cooling fan 11, is cooled, and is sucked into the high-pressure stage compression unit 6.

The air sucked into the high-pressure stage compression section 6 and further compressed to a higher pressure is discharged to a discharge pipe 9, cooled in an aftercooler 10 cooled by blowing air from a first cooling fan 11, and cooled to a predetermined temperature. Is supplied to the compressed air supply destination (not shown).

At this time, when the first cooling fan 11 and the second cooling fan 12 are rotated, the outside air enters the casing 23 from the air suction port 26 and passes around the motor body 3 so as to pass through the motor body 3. After cooling the cooling fan 3, the cooling fan 3 is discharged from the openings 24 and 25 where the first cooling fan 11 and the second cooling fan 12 are located to the outside of the casing 23. The air discharged to the outside of the casing 23 is directly discharged to the outside after directly cooling the intercooler 8 and the aftercooler 10.

The two-axis motor 4 is connected to the high-pressure stage compression unit 6 and the low-pressure stage compression unit 5 by pulleys 14, 15, 1
The drive shaft 2 and the first transmission shaft 13 and the second transmission shaft 17 are not limited to those connected with each other by the power transmission means 8 and 19 and the belts 16 and 20, but are connected by other power transmission means such as by providing gears to the first transmission shaft 13 and the second transmission shaft 17 for connection. Is also good.

As described above, both ends of the drive shaft 2 of the double-shaft motor 4 are connected to the low-pressure stage and high-pressure stage compression units 5 and 6 and to the cooling fans 11 and 12, respectively. Because the intercooler 8 was located at 11 and the aftercooler 10 was located at the high-pressure stage cooling fan 12,
The overall size of the compressor 1 can be made compact.

Further, a casing 23 surrounding the two-axis motor 4 and the two compression parts 5 and 6 and having openings 24 and 25 located at both ends of the cooling fans 11 and 12 is provided at both ends. Since the air suction ports 26 are formed so that the suction flows of the cooling fans 11 and 12 are discharged from the openings 24 and 25 through the two-axis motor 4, the air sucked into the cooling fans 11 and 12 is efficiently used to form the motor body 3. Can be sufficiently cooled, and a sufficient motor cooling capacity can be ensured even if the rotation speed of the double-axis motor 4 is reduced.

Since the intercooler 8 and the aftercooler 10 are cooled by the separate cooling fans 11 and 12, it is not necessary to arrange them in front of one cooling fan, and the intercooler 8 and the aftercooler 10 can be cooled in a large size. Compressor 1 even with high efficiency
The overall size can be made compact.

[0030]

In summary, according to the present invention, the following excellent effects can be obtained.

(1) According to the first aspect of the invention, the size of the entire compressor can be reduced.

(2) According to the second aspect of the present invention, a sufficient motor cooling capacity can be ensured even if the rotation speed of the two-axis motor is reduced.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of an inverter-controlled two-stage screw compressor showing a preferred embodiment of the present invention.

FIG. 2 is a view taken along the line II-II in FIG.

FIG. 3 is a detailed plan view of FIG. 1;

FIG. 4 is a side view of FIG. 3;

FIG. 5 is a front view of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inverter control 2 stage screw compressor 2 Drive shaft 4 Double shaft motor 5 Low pressure stage compression unit 6 High pressure stage compression unit 8 Intercooler 10 Aftercooler 11 Cooling fan 12 Cooling fan 23 Casing 24 Opening 25 Opening 26 Air suction port

Claims (2)

[Claims] 1. A low-pressure stage compression unit and a high-pressure stage compression unit are connected via an intercooler, and an aftercooler is connected to the discharge side of the high-pressure stage compression unit. These low-pressure and high-pressure stage compression units are inverter-controlled. In the inverter-controlled two-stage screw compressor driven by an AC motor, the AC motor is a double-shaft motor, and a low-pressure stage and a high-pressure stage are connected to both ends of a drive shaft of the double-axis motor, respectively. An inverter-controlled two-stage screw compressor, wherein the intercooler is located at the low-pressure stage cooling fan, and the aftercooler is located at the high-pressure stage cooling fan. 2. A casing which surrounds the two-shaft motor and the two compression parts and has openings located at both ends of the two cooling fans, and a suction flow of the cooling fan passes through the two-shaft motor on a side surface of the casing. 2. The inverter-controlled two-stage screw compressor according to claim 1, wherein an air suction port is formed so as to be discharged from the opening.