JP4145830B2 - Oil-cooled compressor - Google Patents

Description

  The present invention relates to an oil-cooled compressor that supplies oil to a rotor chamber.

Conventionally, oil-cooled compressors that supply oil to a rotor chamber in addition to a suction-side bearing, a shaft seal, and a discharge-side bearing / shaft seal have been known, and are a type of oil-cooled compressor. A certain oil-cooled screw compressor is disclosed in Patent Document 1.
JP 2003-328773 A

An oil-cooled screw compressor described in Patent Document 1 incorporates a pair of male and female screw rotors that are rotatably provided and mesh with each other, connected to a suction flow path and a discharge flow path, and the discharge flow Oil separation / recovery unit installed in the passage, and oil flow from the lower part of this oil separation / recovery unit to oil supply locations such as bearings / shaft seals and rotor chambers in the compressor body via the oil cooler and on-off valve And road. The on-off valve is connected to control means for controlling the opening and closing so that oil is periodically guided to the oil supply location. In other words, the control means supplies oil to the compressor body during one cycle obtained by adding a time T _C longer than the time T _{O when the} on-off valve is closed to a time T _O when the on-off valve is open. the amount of it is an optimum lubrication flow q _OPT in the case where the average oil amount q _AV divided by the time of the one cycle and a continuous oil supply to the compressor body.

In the oil-cooled screw compressor described in Patent Document 1, as with a general oil-cooled compressor, the purpose of lubrication is 1) removal of compression heat in the gas compression process, which is supplied to the rotor chamber, and 2) Lubricating and sealing the outer peripheral surface of the rotor, 3) Shaft sealing of the discharge-side rotor shaft, and lubrication of the bearing, 4) Shaft sealing of the suction-side rotor shaft, and the bearing, driving side large gear, driven side small gear, gear chamber, etc. It is divided into four types of lubrication of the speed increasing device configured as described above.
Among these, for 1) to 3), the supplied oil is led from the discharge port to the oil separator / collector before passing through the suction port of the compressor body, where it is separated and recovered from the gas and repeatedly circulated. Be made. On the other hand, in the case of 4), after being guided to a suction passage or a suction port which is normally in a pressure state of substantially atmospheric pressure through a lubrication point such as a bearing / shaft seal on the suction side and a speed increasing device, Along with the suction gas, it is discharged together with the gas through a gas compression step. The same applies to the case of 3). In the case of 4), the temperature of the supplied oil is higher than the temperature of the suction gas, and the oil that has passed through the oil supply points such as the bearing and shaft seal on the suction side is The temperature rises corresponding to the mechanical loss at the refueling point.

For this reason, the oil supplied for the purpose of 4) raises the temperature of the suction gas and causes thermal expansion, resulting in a problem that the suction flow rate of the compressor body decreases.
In the case of 4), the oil that has passed through the oil supply location such as the bearing and shaft seal on the suction side may stay in the suction port, and this oil is agitated by the rotor that rotates at high speed, resulting in energy loss. Has occurred.
The present invention aims to eliminate such a conventional problem, avoids a rise in the temperature of the suction gas, prevents a decrease in the suction flow rate, and eliminates energy loss caused by the oil stagnating at the suction port being agitated by the rotor. It is an object of the present invention to provide an oil-cooled compressor that makes it possible.

In order to solve the above problems, the present invention compresses a gas sucked through a suction passage of a compressor body connected to the suction passage from the suction passage under oil supply, and then discharges the passage connected to the compressor body. Guided along with the oil associated with the oil separator / collector installed in the cylinder, where the oil is separated and recovered from the gas, and the recovered oil is supported by the oil passage through the bearing / shaft seal in the compressor body, rotor chamber, etc. In an oil-cooled compressor that is led to and repeatedly used, a seal member is provided in a portion that covers the rotor shaft of the compressor body, and the suction-side oil supply location and the suction port in the compressor body are liquidated. A partition wall for tightly blocking and an oil return passage for guiding the oil supplied to the suction side oil supply portion to the gas compression space in the rotor chamber that does not communicate with the suction port are provided.

  According to the oil-cooled compressor according to the present invention, the oil whose temperature has risen through the oil supply location such as the bearing and shaft seal on the suction side does not flow into the suction port, and the suction gas caused by the oil whose temperature has increased A rise in temperature is avoided, and a decrease in the suction flow rate is prevented, and oil that has passed through the oil supply location such as the bearing and shaft seal on the suction side is not retained in the suction port, and this oil is stirred by the rotor. There is an effect that it is possible to eliminate the energy loss caused by this.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an oil-cooled screw compressor 1 that is an example of an oil-cooled compressor according to the present invention, and a suction passage 12 is provided on one side of a compressor body 11 of the oil-cooled screw compressor 1. Each of the discharge flow paths 14 in which the oil separation and recovery unit 13 is interposed is connected to the other side, and an oil flow path 15 is connected to the lower part of the oil separation and recovery unit 13. Further, an oil return channel 16 is provided in the compressor body 11.

  The compressor main body 11 has a housing 23 formed with a suction port 21 opened in the suction flow channel 12 and a discharge port 22 opened in the discharge flow channel 13, and a rotor chamber 24 between the suction port 21 and the discharge port 22. A pair of male and female screw rotors 25 and 26 that mesh with each other are housed therein. Each rotor shaft extending to the suction side of each of the screw rotors 25 and 26 is a bearing / shaft seal 25S, 26S, and each rotor shaft extending to the discharge side of each of the screw rotors 25, 26 is a bearing / shaft seal 25D, 26D is rotatably supported.

  A gear chamber 28 separated from the suction port 21 by a partition wall 27 is provided, and a drive mounted in the gear chamber 28 so as to be integrally rotatable with a rotary drive shaft 31 driven by an output shaft of a motor (not shown). A large side gear 32 and a driven small gear 33 that engages with a large driving gear 32 that is attached to a rotor shaft on the suction side of the screw rotor 26 that passes through the partition wall 27 so as to rotate integrally are accommodated. The partition wall 27 is provided with bearing / shaft seal portions 25S and 26S. The rotary drive shaft 31 is rotatably supported by a bearing / shaft seal 34 provided on the motor side wall of the gear chamber 28 and a bearing / shaft seal 35 provided on the partition wall 27. . The rotation of the output shaft is transmitted from the drive side large gear 32 to the driven side small gear 33 with an increased number of rotations, and the screw rotor 26 rotates and meshes with the rotation of the driven side small gear 33. The rotation is transmitted to the screw rotor 25. Furthermore, the partition wall 27 is formed so that the suction side bearing / shaft sealing portions 25S, 26S, 35 and the suction port 21 can be liquid-tightly cut off. In addition to the bearing / shaft seals 25S, 26S, and 35, the partition wall 27 blocks the driving side large gear 32, the driven side small gear 33, and the gear chamber 28 that accommodates them from the suction port 21. .

  The suction flow path 12 is provided with a suction filter 41, whereby gas from which foreign matter including dust and dust has been removed is guided to the suction port 21 of the compressor body 11.

  As described above, the oil separation / recovery unit 13 is interposed in the discharge flow path 14, the oil separation element 51 is provided in the upper part in the oil separation / recovery unit 13, and the lower part is an oil reservoir 52. A portion of the discharge flow path 14 extends from the upper part of the oil separation element 51 toward the supply destination of the compressed gas, and the oil reservoir 52 communicates with the oil flow path 15.

  The oil flow path 15 passes through oil coolers 61 and an oil filter 62 to oil supply locations such as a bearing / shaft seal in the compressor body 11 and the rotor chamber 24. Specifically, the oil flow passage 15 allows the discharge-side bearing / shaft seals 25D, 26D, the suction-side bearings / shaft seals 25S, 26S, the discharge-side bearings / shaft seals 25D, 26D, and rotation. Oil is supplied to the bearing / shaft seals 34 and 35 of the drive shaft 31 and the gas compression space in the rotor chamber 24.

  One end of the oil return channel 16 is provided at a position where oil can be recovered through the above-described oil supply location on the suction side, and the other end is connected to the gas compression space (portion indicated by R in the figure). It is provided and collects oil that has passed through the oil supply location on the suction side, and guides this oil to the gas compression space. By the way, as described above, the partition wall 27 is formed so that the suction-side bearing / shaft seal portion and the suction port 21 can be liquid-tightly cut off, and oil leaks from the suction-side bearing / shaft seal portion to the suction port 21. Therefore, the oil that has passed through the above-mentioned oil supply location on the suction side is recovered in the oil return channel 16 without leaking to the suction port 21. The oil return channel 16 is not limited to the illustrated one, and the oil return channel 16 is used to prevent backflow of oil from the gas compression space side to the bearing / shaft seal side on the suction side. A check valve may be interposed in the oil return passage 16 to cause a smooth oil flow from the suction side bearing / shaft seal portion side to the gas compression space side. An oil pump may be interposed, and an oil cooler may be interposed in the oil return passage 16. Further, as a structure in which oil can flow into the gear chamber 28 from the bearing / shaft seal portions 25S, 26S, 35 which are the oil supply locations on the suction side, one end of the oil return passage 16 is provided in the gear chamber 28, and the gear chamber 28 It may be possible to recover the oil.

  In the oil-cooled screw compressor 1 having the above-described configuration, the clean gas sucked from the suction port 21 of the compressor body 11 through the suction flow path 12 via the suction filter 41 is supplied from the oil flow path 15. The oil is compressed below, discharged from the discharge port 22 together with oil to the discharge flow path 14, and guided to the oil separator / collector 13. In the oil separator / collector 13, the oil is separated from the gas in the process of passing through the oil separation element 51 and collected in the oil reservoir 52. The clean gas from which the oil has been separated, that is, the compressed gas, is sent out from the upper part of the oil separator / collector 13 to the portion of the discharge flow path 14 from the supply destination of the compressed gas, and the oil in the oil reservoir 52 is transferred by the oil flow path 15. Through the oil cooler 61 and the oil filter 62, the oil is guided to the above-described oil supply location.

  The oil supplied to the rotor chamber 24 and the discharge-side bearing / shaft seals 25D and 26D is collected by the oil separator 13 along with the gas from the discharge port 22 without passing through the suction port 21. The oil supplied to the bearing / shaft seals 25S, 26S, 35 on the suction side is recovered in the oil return flow path 16 without leaking to the suction port 21 by the partition wall 27, and the gas compression space. To the oil separation and recovery device 13 along with the gas from the discharge port 22.

Therefore, in this oil-cooled screw compressor 1, the oil whose temperature has risen does not leak into the suction port 21, and the temperature of the suction gas and the suction flow rate do not decrease due to the oil whose temperature has risen. There is no energy loss due to the oil being stirred by the screw rotors 25 and 26 due to the retention of. Further, since the gas compression space in which the oil is returned by the oil return passage 16 does not communicate not only with the discharge port 22 but also with the suction port 21, there is no possibility that the returned flow rate will be reduced by the returned oil.
The oil return channel 16 may be formed by being drawn out of the housing 23 of the compressor body 11 as shown, or may be formed by the channel in the housing 23 without being taken out of the housing 23. Good.
In addition, it is desirable to provide a seal member on the partition wall 27 that covers the rotor shaft of the screw rotor 26 and the rotor shaft of the screw rotor 25.

It is a figure which shows the outline of the whole structure of the oil-cooled screw compressor which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Oil-cooled screw compressor 11 Compressor body 12 Suction flow path 13 Oil separation and recovery device 14 Discharge flow path 15 Oil flow path 16 Oil return flow path 21 Suction port 22 Discharge port 23 Housing 24 Rotor chambers 25 and 26 Screw rotor 25S , 26S (suction side) bearing / shaft seal portion 25D, 26D (discharge side) bearing / shaft seal portion 27 partition wall 28 gear chamber 31 rotary drive shaft 32 drive side large gear 33 driven side small gear 34 (motor side wall portion) ) Bearing / shaft seal 35 (partition wall) Bearing / shaft seal 41 Suction filter 51 Oil separation element 52 Oil reservoir 61 Oil cooler 62 Oil filter R Gas compression space

Claims (1)

After the gas sucked from the suction passage through the suction port of the compressor main body connected thereto is compressed under oil supply, it is accompanied by an oil separation and recovery device interposed in the discharge passage connected to the compressor main body. Oil-cooled type that guides along with oil, separates and recovers oil from gas, and guides the recovered oil to oiling points such as bearings, shaft seals, and rotor chambers in the compressor body through the oil flow path, and repeatedly uses them In the compressor, a seal member is provided in a portion covering the rotor shaft of the compressor main body, a partition wall that liquid-tightly blocks the suction side oil supply portion and the suction port in the compressor main body, and the suction side oil supply An oil-cooled compressor, comprising: an oil return passage that guides oil supplied to a location to a gas compression space in the rotor chamber that does not communicate with the suction port .

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