JP2008255889A - Energy-saving and starting-up operation smoothing device of compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an energy-saving and starting-up smoothing device for a compressor in which an amount of using air is reduced and energy is remarkably saved even in a range where rotation control of a motor by an inverter is impossible and further a smooth operation is possible and no oil bubble is made even in an increase in air used by the compressor and in restarting. <P>SOLUTION: A short circuit 2 which returns discharged air directly to a compressor main body 4 is formed at a discharging side of the compressor main body 4. An electromagnetic valve 1 which operates by a pressure switch 3 is provided in the short circuit 2. Then, when a used air amount has reached about 20% of a maximum amount of the using air, the electromagnetic valve 1 opens and thereby no air is sent to a side of a receiver tank 8. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an energy-saving start-up smoothing device for a compressor that improves the energy-saving effect when reducing the amount of air discharged from the compressor and that facilitates smoothing at the time of restart.

FIG. 3 shows the overall configuration of a compressor that is generally used. However, description of devices not related to the present invention is omitted here.
The compressor body 4 is operated by a motor 5, and the motor 5 is provided with an inverter 6 that controls the number of rotations thereof. Discharged air containing oil from the compressor body 4 is sent to the receiver tank 8 via the check valve 7. The air containing oil in the receiver tank 8 is separated by the oil separator 9, and the air is sent to the aftercooler 10 via the pressure switch 3 and sent to the air use side via the dryer 11. The compressor body 4 is connected to an air cleaner 13 via an air capacity adjustment valve 12.

In the above configuration, when the amount of air used decreases, the pressure of the air used increases. This increase in pressure is detected by the pressure switch 3, and the inverter 6 acts to reduce the rotation of the motor 5. As a result, the amount of air discharged from the compressor body 4 is reduced, which corresponds to a reduction in the amount of air used. Control of the number of rotations of the motor 5 by the inverter 6 is possible until the normal use amount of air reaches about 20% of the maximum use amount, but generally it cannot be controlled below that. That is, the inverter 6 has an “operation range”. Therefore, if the amount of air used exceeds the “operating range”, the air capacity adjustment valve 12 operates to reduce the amount of intake air. At the same time, the pressure in the receiver tank 8 is reduced. As described above, energy saving is attempted when the amount of air used is reduced, but the energy saving amount is small.
In addition, as described above, when the air pressure in the receiver tank 8 is reduced, there is a problem that when the amount of air on the use side increases, the pressure does not rise in time and the pressure of the air used decreases.
In addition, when the compressor is stopped, the pressure in the compressor body 4 and the receiver tank 8 is lowered to facilitate the restarting. By reducing this pressure, the oil present inside the receiver tank 8 and the like is reduced. There is a problem that foaming occurs and the oil filter or the like is covered with oil, leading to a decrease in oil separation function.

Although there is no effective known technique for solving the above-mentioned problems, there are, for example, “Patent Document 1” and “Patent Document 2” as known techniques related to the reduction of air consumption. However, these are quite different from the present invention.
Japanese Patent Laid-Open No. 11-166442 (FIG. 1) Japanese Patent Application Laid-Open No. 2004-3727 (FIG. 1)

As described above, in the prior art, there is no simple effective means for reducing the amount of air on the use side and achieving an energy saving effect and smooth start-up.
FIG. 2 is a diagram showing the relationship between the amount of air used and electric power. In the prior art, the relationship is indicated by straight lines C and B, and the energy saving effect at 20% or less of the amount of air used is extremely small. It was. Further, as described above, in the prior art, it is not possible to smoothly start up when the amount of air used is increased, and there is no means for eliminating the deterioration of the oil separation function due to bubbling of oil when the compressor is stopped.

  The present invention has been invented in view of the above circumstances, energy saving is sufficiently performed when the "operation range" of the inverter is exceeded, and the response when the amount of air used increases is smoothly performed, An object of the present invention is to provide an energy saving start-up smoothing device for a compressor that can prevent harmful effects caused by bubbling of oil.

  In order to achieve the above object, the present invention is configured to reduce power consumption when the amount of air used is reduced and to make the rise smooth when the amount of air used is increased again. An energy saving start-up smoothing device for a compressor, which eliminates an air capacity adjustment valve interposed between the air cleaner and the compressor body and returns the discharge air to the air discharge side of the compressor body to the compressor body side And a solenoid valve that opens and closes in response to an increase or decrease in the amount of air used is provided in the short circuit.

  The invention according to claim 2 is characterized in that the solenoid valve is formed so as to be opened outside an operating range corresponding to an amount of air used by an inverter of a motor connected to a compressor body.

  According to the energy saving start-up smoothing device of the compressor of claim 1 of the present invention, when the conventionally used air capacity adjustment valve is eliminated and the use air amount on the use side is reduced, the discharge air from the compressor body is received on the receiver tank side. It is not sent to the compressor, but is returned to the compressor body via a short circuit, so that the increase in pressure on the use side is reduced, and even if the inverter is not operated, the motor speed can be reduced, resulting in a significant energy saving effect. Can be raised. Further, since there is no need to lower the pressure in the receiver tank, the pressure can be smoothly increased when the amount of air used is increased, and the problem of oil bubbling associated with the stoppage of the compressor is solved.

  According to the compressor energy saving start-up smoothing device of claim 2 of the present invention, since the solenoid valve is opened outside the “operating range” of the inverter and the short circuit is connected to the compressor body, the “operating range” Significant improvement in energy saving effect in the following can be achieved.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a compressor energy saving start-up smoothing apparatus according to the present invention will be described below in detail with reference to the drawings.
FIG. 1 shows the overall configuration of a compressor according to the present invention. In FIG. 1, redundant description of the same constituent members as those in FIG. 3 and members that perform substantially the same function is omitted.
As shown in FIG. 1, a short circuit 2 is connected to the compressor body 4. The short circuit 2 is for short-circuiting the discharge side and the suction side of the compressor body 4, and the electromagnetic valve 1 is interposed in the short circuit 2. The electromagnetic valve 1 is connected to a pressure switch 3 and is configured to be opened and closed by the pressure switch 3.
As a structural feature of the compressor of the present invention, the air capacity adjustment valve 12 is not provided, and the air cleaner 13 is directly connected to the compressor body 4. In addition, since the air capacity adjustment valve 12 is abolished, there are no pipes connected thereto.

  In the compressor configuration described above, during normal operation, the compressed air from the compressor body 4 is sent into the receiver tank 8 via the check valve 7 and further separated by the oil separator 9 and then via the pressure switch 3 and the like. Then, it is sent to the aftercooler 10 side and sent to the use side via the dryer 11.

  When the amount of air used on the air use side is reduced, first, the inverter 6 is operated, and the motor 5 is rotated at a low speed to adjust the discharge amount of compressed air from the compressor body 4. However, the amount of air used is further reduced. For example, when it reaches about 20% of the maximum amount used, the inverter 6 does not operate. The state is detected by the pressure switch 3 and the solenoid valve 1 is opened. By opening the electromagnetic valve 1, the discharge air from the compressor body 4 is not sent to the receiver tank 8 side, but sent to the short circuit 2 and returned to the compressor body 4 side. Therefore, even if the amount of air used is reduced and the inverter 6 does not operate, the amount of air discharged from the compressor body 4 is reduced, the load on the motor 5 is reduced, and energy saving is achieved as a result. FIG. 2 shows such a state, where the horizontal axis represents the amount of air used and the vertical axis represents power. As shown in the drawing, the power is greatly reduced as indicated by the dotted line A, resulting in energy saving.

  On the other hand, as described above, in the case of the present invention, since air is not sent to the receiver tank 8 side, the pressure in the receiver tank 8 is not reduced as in the prior art, and the amount of air used increases accordingly. The operation of the compressor body 4 is performed smoothly. Further, since the pressure in the receiver tank 8 is not lowered, no oil bubbles are generated, and the oil separating ability in the oil separator 9 is not lowered.

  In the above description, the “operation range” of the inverter 6 is set to 20%, but of course not limited to this. Further, the present invention is not limited to the above contents, and the same technical category is of course applied.

  The present invention is not limited to an ordinary compressor that uses oil as described above, but can be applied to all devices that output pressurized air and has a wide range of uses.

The whole block diagram of the compressor of the present invention. The diagram which shows the energy-saving effect in the compressor of this invention. The whole block diagram of the conventional compressor.

Explanation of symbols

1 Solenoid Valve 2 Short Circuit 3 Pressure Switch 4 Compressor Body 5 Motor 6 Inverter 8 Receiver Tank

Claims (2)

  An energy-saving start-up smoothing device for a compressor configured to reduce power consumption when the amount of air used is reduced and to facilitate start-up when the amount of air used is increased again. Eliminates the air capacity adjustment valve interposed between the compressor body, and provides a short circuit on the air discharge side of the compressor body to return the discharge air to the compressor body side. An energy saving start-up smoothing device for a compressor, characterized by providing an electromagnetic valve that opens and closes.   2. The energy saving start-up smoothing device for a compressor according to claim 1, wherein the solenoid valve is formed so as to be opened outside an operating range corresponding to an amount of air used by an inverter of a motor connected to a compressor body.

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