JPH04365987A - Oil injection type screw compressor - Google Patents

Abstract

PURPOSE:To achieve long lifespan of a bearing. CONSTITUTION:A compressor main body 1 is provided between a discharging exit 8 of the compressor main body 1 and a discharging channel 9 connected to the discharging exit, above an oil tank 10 for storing oil separated from discharged gas. In an oil injection type screw compressor in which a motor 2 is arranged above the compressor main body 1, and in which the compressor main body 1 is belt-driven, a discharge port 23 of the compressor main body 1 is provided on the side of the oil tank 10.

Description

[Detailed description of the invention]

0001

[Industrial application field]

The present invention relates to an oil-cooled screw compressor which has a structure in which a compressor main body and its driving section are stacked on an oil tank, and in which the compressor main body is driven by a belt.

0003

2. Description of the Related Art Conventionally, as shown in FIG.
The compressor main body 42 is connected to the motor 43 via a drive pulley 44, a belt 45, and a driven pulley 46.
An oil-cooled screw compressor that is driven by is known. The rotor chamber in the compressor main body 42 has a discharge side,
A pair of male and female screw rotors 49 are supported on the suction side by angular ball bearings 47 capable of resisting thrust forces, and are rotatably engaged with each other by roller bearings 48. A port 50 is formed. The compressed gas discharged from the rotating screw rotor 49 is discharged upward from a discharge port 50 and reaches the oil tank 41 below through a discharge flow path 51.

0004

[Problems to be Solved by the Invention] In the conventional oil-cooled screw compressor described above, the discharge port 50 is connected to the screw rotor 49.
It is located above the axis of the For this reason, the angular ball bearing 47 on the discharge side has a large downward force that is a combination of the downward force acting on the roller bearing 48 as a fulcrum based on the tension of the belt 45 and the downward force based on the pressure of the compressed gas on the discharge side. Force will come into play. Since the angular contact ball bearing 47 cannot withstand large loads compared to the roller bearing 48 of the same size, the above-mentioned large loads will shorten the life of the angular contact ball bearing 47. There's a problem. The present invention has been made to address these conventional problems, and an object thereof is to provide an oil-cooled screw compressor that makes it possible to extend the life of the bearings.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a method for separating a compressor main body from discharge gas by interposing the compressor main body between a discharge passage connected to a discharge port of the compressor main body. In an oil-cooled screw compressor, the compressor body is placed above an oil tank for storing oil, and a drive unit is placed above the compressor body, and the compressor body is driven by a belt. It was formed on the oil tank side.

[0006]

[Operation] By forming the screw rotor as described above, the radial load acting on the bearing on the discharge port side that supports the screw rotor is reduced.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a screw compressor according to the invention, in which a suction filter 5, an intake air control valve 6, and a suction casing 7 are installed in a suction passage 4 leading to a compressor body 1, a motor 2, and a suction port 3 of the compressor body 1. An oil tank 10, an aftercooler 11, and a reserve tank 12 are provided in the discharge passage 9 following the discharge port 8 of the compressor body 1, and an oil filter 14, a three-way switching valve 15, and an oil cooler 16 are provided in the lubricating oil circulation passage 13. It is provided and formed. The compressor main body 1 is fixed to a suction casing 7, and houses therein a pair of male and female screw rotors 19 which are rotatably supported by a bearing 17 on the discharge side and a bearing 18 on the suction side inside the suction casing 7 and mesh with each other. However, it can be driven by a motor 2 via a drive pulley 20, a driven pulley 21, and a belt 22. Further, an intake air adjustment valve 6 is fixed to the intake casing 7, and a suction filter 5 is fixed to the intake air adjustment valve 6, and a suction flow path 4 is formed by the communication space inside each.

Here, since the discharge port 23 of the compressor main body 1 is formed downward, the downward force acting on the discharge side bearing 17 based on the tension of the belt 22 with the suction side bearing 18 as a fulcrum is applied to the discharge side bearing 17. , a force reduced by the upward force based on the gas pressure on the discharge side comes to act. That is, the force acting on the bearing 17 is reduced by this gas pressure, and the bearing life is extended. In this case, in addition to the force based on the tension of the belt 22, a force based on this gas pressure acts on the bearing 18 on the suction side. A roller bearing is used in the bearing, which can withstand a large radial load, and the shortening of the lifespan of the bearing 18 compared to that of the bearing 17 is not a problem.

The oil tank 10 and the reserve tank 12 are formed into one container with a partition plate 24 having an upwardly convex surface and an arch-shaped cross section disposed below the oil tank 10 . Also, oil tank 1
The compressor main body 1 is installed by installing a mounting table 25 upright around the periphery of the oil tank 10, forming an inlet 26 passing through the center of the upper surface of the oil tank 10, and fixing the suction casing 7 on the mounting table 25. The inlet port 26 is supported in a cantilevered state.
The discharge port 8 is pressed against the inlet port 26 to be in close contact with the inlet port 26 while being isolated from the outside through an O-ring 27. Further, an oil separation section 28 is provided upright above the peripheral portion of the oil tank 10 on the opposite side from the above-mentioned mounting table 25, and an oil separation element 29 is provided above the space within this oil separation section 28, and an oil separation element 29 is provided at the discharge port. 8, a discharge flow path 9 is formed which continues from this oil separation element 29 to an aftercooler 11 and a reserve tank 12 via a pressure holding check valve 30. In addition, in the figure, the discharge flow path 9 is partially omitted, and the * marks communicate with each other.

The upper surface of the oil separation section 28 is formed to have a predetermined height with respect to the upper surface of the mounting table 25, and the suction casing 7 and the intake control valve 6 are also formed to have predetermined heights, respectively. The suction casing 7 is placed on the mounting table 25.
By simply stacking and fixing the intake control valves 6, the top surface of the intake control valves 6 and the top surface of the oil separation part 28 are made to be at the same height. The motor 2 is fixed. The lubricating oil circulation passage 13 exits from the oil reservoir 32 at the bottom of the oil tank 10 and reaches oil supply points such as the bearings and shaft seals in the compressor body 1 and the suction casing 7.

Next, the operating state of the apparatus constructed as described above will be explained. When the screw rotor 19 is rotationally driven by the motor 2 via the drive pulley 20, driven pulley 21, and belt 22, the air sucked in by the screw rotor 19 via the suction filter 5 passes through the suction channel 4 and reaches the suction port 3. It is sucked in, compressed, and discharged to the discharge port 8 together with the lubricating oil supplied to the bearings and the like. The compressed air discharged together with this lubricating oil enters the oil tank 10 in the discharge flow path 9, and is separated into gas and liquid by the oil separation element 29, and the lubricating oil drops and is temporarily stored in the oil reservoir 32. The oil-separated compressed air reaches the aftercooler 11, where it is cooled by air blowing from a fan (not shown), is temporarily stored in a reserve tank 12, and then is sent out of the machine as required.

On the other hand, the lubricating oil in the oil reservoir 32 passes through the oil filter 14 and the three-way switching valve 15 and reaches the oil cooler 16, where, like the compressed air in the aftercooler 11,
After being air-cooled by air blowing from a fan (not shown) and sent to the oil supply location in the compressor main body 1 and the suction casing 7, it is collected in the oil reservoir 32 and thereafter used for circulation in the same manner as described above. Note that if the lubricating oil in the oil reservoir 32 does not need to pass through the oil cooler 16, such as when the lubricating oil is at a temperature that does not require cooling, the lubricating oil can be passed through the oil filter by switching the flow path of the three-way switching valve 15. 14 so that the oil can be directly sent to the above-mentioned oil supply location, bypassing the oil cooler 16. Here, since the oil tank 10 and the reserve tank 12 are formed as one container, the entire device can be made compact, and the lubricating oil in the oil reservoir 32 is stored in a partition plate with an arched cross section to improve pressure resistance. It is adjacent to the cooled compressed air in the reserve tank 12 via 24, so that the lubricating oil is also cooled by this cooled air.

Further, for example, when the compressor is started, bubbles are generated in the lubricating oil in the oil reservoir 32, and the oil level rises. On the other hand, in order to maintain the gas-liquid separation performance of the oil separation element 29, it is necessary to prevent the oil separation element 29 from soaking in lubricating oil even when the oil level rises, and the oil level and the oil separation element 29 You cannot get too close to it, and you need to keep it a certain distance away. For this reason, conventional oil tanks have a large height and are bulky as a whole, whereas in this embodiment, an oil separator is installed above the periphery on one side of the oil tank 10. By providing the oil separation element 29 above the space within the section 28, a sufficiently large distance from the oil level of the oil reservoir section 32 is ensured, and the other space can be used effectively. That is, the oil separation section 2
The height of the parts of the oil tank 10 other than 8 is reduced to provide the minimum necessary volume to store the lubricating oil necessary to continue circulating the lubricating oil within the device, and this height is created by lowering the height. The compressor main body 1 is placed in the space with the oil separator 28, the suction casing 7, and the intake control valve 6 between the two protrusions. It is made compact.

Furthermore, the partition plate 24 has an arched cross section, and the cross section of the oil reservoir 32 widens upward, so that when the oil level rises due to the generation of air bubbles, degassing is prevented. This contributes to promoting this, suppressing the oil level rise, and reducing the height of the oil tank 10. Furthermore, oil tank 1
0 has a shape with a small height and a large horizontal cross section, except for the oil separation part 28, so when vibration is applied to the center of the upper surface of the oil tank 10, it is easy to bend, and due to the same action as a drum, it becomes large. On the other hand, even if the peripheral portion receives vibration, it is difficult to generate sound because the peripheral portion is closer to a rigid body than the central portion. Therefore, in this embodiment, the compressor main body 1, which easily generates vibrations and becomes a source of noise, is supported by the mounting table 25 via the suction casing 7 so that the oil tank 10 receives vibrations around the oil tank 10. The center portion of the upper surface of the compressor is brought into contact with the compressor main body 1 via an O-ring 27 to reduce noise.

In addition, the motor 2, which is likely to be a source of noise along with the compressor body 1, is supported by the oil separation section 28 via the support plate 31, the support plate 31, the intake control valve 6, and the mounting table 25 via the suction casing 7. Similarly to the above, vibrations are propagated to the periphery of the oil tank 10 to reduce noise. In addition, in the above embodiment, the motor 2, which is the driving part, is supported by the oil separation part 28, the suction casing 7, and the intake air regulating valve 6 via the support plate 31, but the present invention is not limited to this. Alternatively, each of the above-mentioned supporting parts may be supported by a pedestal erected around the oil tank 10.

Preferably, the oil tank 10 is formed of a thick walled material. In this case, as shown in FIG. It is also possible to lower the amount of oil and make effective use of the space on the sides of the oil separation section 25. In the above embodiments, the compressed gas is air, but the present invention is not limited to this, but also includes devices that use gases other than air as the compressed gas.

[0017]

[Effects of the Invention] As is clear from the above description, according to the present invention, the compressor body is separated from the discharged gas by interposing it between the discharge channels connected to the discharge port of the compressor body. In an oil-cooled screw compressor, the compressor body is placed above an oil tank for storing oil, a driving part is placed above the compressor body, and the compressor body is driven by a belt, and the discharge port of the compressor body is connected to the It is formed on the oil tank side. For this reason, the radial load acting on the bearing on the discharge port side that supports the screw rotor is reduced, making it possible to extend the life of the bearing. Even if the tightening bolt becomes loose, the discharge side of the compressor main body is always kept pressed against the oil tank by the force based on the belt tension, so that the compressed gas can be prevented from leaking to the outside.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an oil-cooled screw compressor according to the present invention.

FIG. 2 is an overall configuration diagram of a conventional oil-cooled screw compressor.

[Explanation of symbols]

1 Compressor main body 2 Motor 8 Discharge port 9 Discharge channel 10 Oil tank 20 Drive pulley 21 Belt 22 Driven pulley 23 Discharge port

Claims (1)

[Claims] Claim 1: A compressor body is disposed above an oil tank that stores oil separated from discharged gas, interposed between a discharge passage connected to a discharge port of the compressor body, An oil-cooled screw compressor in which a driving portion is disposed above and a compressor body is driven by a belt, characterized in that a discharge port of the compressor body is provided on the oil tank side. type screw compressor.