JP2002235674A - Method for operating a plurality of compressors - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for operating a plurality of compressors allowing corresponding to a rapid load change and reducing energy loss by non-load operation of the compressors. SOLUTION: Three turbo compressors 2a, 2b, 2c for basal operation, five oil screw type compressors 3a, 3b, 3c, 3d, 3e for controlling number of compressors and two dry screw type compressors 4a, 4b for fine pressure control are mounted on an air supply line 1 in parallel. When both the dry screw type compressors 4a, 4b are in a no-load operation state according to the load change of the air supply line 1, one of the oil screw type compressors 3a, 3b, 3c, 3d, 3e is stopped after a predetermined period and the dry screw compressors 4a, 4b are shifted from the no-load operation state to a load operation state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for operating a plurality of compressors for supplying air at a predetermined pressure to an air supply line.

[0002]

2. Description of the Related Art Conventionally, in a production plant, for example, three base units are operated so that the air pressure of an air supply line is maintained within an upper limit and a lower limit of a set pressure (only full load operation).
Turbo compressor, five oil screw type (OS) compressors for controlling the number of units, and two dry screw type (NDS) compressors for controlling the micro pressure (fast response to load operation and no load operation). They are installed in parallel.

As a method of operating such a plurality of compressors, a pressure sensor detects the air pressure in the air supply line, and the air pressure in the air supply line is set to the upper and lower limits of the set pressure even if the load fluctuates. The command signal for full-load operation is supplied from the sequencer installed on the control panel to the turbo compressor for base operation and the oil screw compressor for unit control so that it is controlled within the range of A command signal of load operation or no-load operation is sent to the dry screw type compressor.

[0004]

However, when two dry screw compressors for micro pressure control are brought into a no-load operation state by the micro pressure control, the air pressure of the air supply line is set to the upper limit of the set pressure. If it is maintained within the lower limit range, it is not necessary to perform the load operation, so that the no-load operation state continues for a long time, causing an operation loss. In addition, since the order in which the two dry screw compressors for controlling the micro-pressure control enter the no-load operation state is fixed, the operation is biased.

The present invention has been made in view of the above-mentioned problems of the prior art. It is an object of the present invention to be able to cope with a sudden load change and to reduce energy loss due to no-load operation of a compressor. It is an object of the present invention to provide a method of operating a plurality of compressors that can reduce the number of compressors.

[0006]

According to a first aspect of the present invention, there is provided an air supply line comprising a plurality of base operation compressors, a unit control compressor, and a micro pressure control compressor. When the two compressors for micro-pressure control are placed in a no-load operation state in accordance with the load fluctuation of the air supply line, one of the number-control compressors is stopped after a predetermined time and the micro-pressure control is stopped. The control compressor is changed from a no-load operation state to a load operation state.

According to a second aspect of the present invention, in the method for operating a plurality of compressors according to the first aspect, the order in which the low-pressure control compressor enters the no-load operation state is changed by a calendar timer.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a configuration diagram of a compressor system using a plurality of compressors, and FIG. 2 is a timing chart of an operation method of the plurality of compressors according to the present invention.

As shown in FIG. 1, an air supply line 1 of a production factory is provided with a set pressure (for example, an unillustrated processing machine, a press-fitting machine, an impact wrench installed in an assembly process, etc.
In order to supply air controlled to 0.57 to 0.58 MPa), three turbo compressors 2a, 2b, 2
c, five oil screw type (OS) compressors 3a, 3b, 3c, 3d, 3e and two dry screw type (NDS) compressors 4a, 4b are installed in parallel to constitute a compressor system. .

The three turbo compressors 2a, 2b,
Reference numeral 2c denotes a compressor for base operation (only full load operation) for supplying air having a capacity of a base portion of the air supplied to the air supply line 1. Five oil screw compressors 3a, 3b, 3c, 3d, 3e
Is a method in which air of a predetermined capacity is added to the air supplied by the three turbo compressors 2a, 2b, 2c. This is a unit control compressor that does not contribute. Two dry screw compressors 4a, 4
b indicates that the air pressure is the upper limit of the set pressure (for example, 0.58MP
a) and a compressor for fine pressure control (response of load operation and no-load operation is fast) that controls the supply and stop of air quickly so as to be maintained within a range between a) and a lower limit (for example, 0.57 MPa). .

The air supply line 1 is provided with a pressure sensor 5 for detecting air pressure, and an output signal of the pressure sensor 5 is provided to a control panel 6 and is input to a sequencer 7 for controlling each compressor. The control panel 6 has a timer 8 for outputting an on-delay signal after a predetermined time (for example, 40 seconds) after the two dry screw compressors 4a and 4b are in a no-load operation state as an external circuit of the sequencer 7. Is installed. Further, the control panel 6 is provided with a calendar timer 9 as an external circuit of the sequencer 7 for changing the order in which the two dry screw compressors 4a and 4b enter the no-load operation state.

Next, a method of operating a plurality of compressors according to the present invention will be described with reference to a timing chart shown in FIG. Three turbo compressors 2a, 2
b, 2c and 5 oil screw compressors 3
When a, 3b, 3c, 3d, and 3e are in the full load operation state and the two dry screw compressors 4a and 4b are in the load operation state, the pressure P of the air supplied to the air supply line 1 is changed by the load fluctuation. When the upper limit of the set pressure (for example, 0.58 MPa) is reached, the sequencer 7 of the two dry screw compressors 4a and 4b
First, the first dry screw compressor 4a
And outputs a no-load operation command signal in place of the load operation command signal.

Further, if the air pressure P reaches the upper limit of the set pressure again (for example, 0.58 MPa) even when the first dry screw compressor 4a is in the no-load operation state, the sequencer 7 The non-load operation command signal is output to the second dry screw compressor 4b instead of the load operation command signal.

The sequencer 7 activates the timer 8 at the same time as a command signal for a no-load operation to the second dry screw compressor 4b. When 40 seconds have elapsed since the start of the timer 8, the sequencer 7 that has detected the on-delay signal of the timer 8 outputs one of the five oil screw compressors 3a, 3b, 3c, 3d, and 3e. A stop command signal is output to the screw compressor 3a instead of the full load operation command signal.

Here, even if the two dry screw compressors 4a and 4b enter the no-load operation state, they immediately
The reason why the two oil screw compressors 3a are not stopped is that the two dry screw compressors 4a,
Unless the no-load operation state of 4b continues for 40 seconds or more, the dry screw type compressor 4
a or 4b is hunting (repeated running / stopping)
This is because the pressure P is not stable and is not preferable.

On the other hand, the sequencer 7 outputs a load operation command signal to the two dry screw type compressors 4a and 4b in place of the no-load operation command signal simultaneously with the stop command signal to the oil screw type compressor 3a. I do. If the load on the air supply line 1 is almost the same as when the two dry screw compressors 4a and 4b enter the no-load operation state, the pressure P is set to the upper limit (for example, 0.58 MPa) and the lower limit (for example, 0.58 MPa). , 0.57
(MPa).

As described above, even when one oil screw compressor 3a for controlling the number of units is stopped due to a load change, the air pressure P becomes the upper limit (for example, 0.58MPa).
a) and the lower limit (for example, 0.57 MPa), one oil screw compressor 3a is stopped and the two dry screw compressors 4a and 4b are operated without load. By changing from the state to the load operation state, unnecessary no-load operation can be avoided, and the number of operating compressor units can be reduced as a whole, so that energy efficiency can be improved.

When the air pressure P falls below the lower limit of the set pressure (for example, 0.57 MPa) due to load fluctuation, the sequencer 7 instructs the oil screw compressor 3a for controlling the number of units to stop. An operation command signal is output instead of the signal. Then, the air pressure P is set to an upper limit (for example, 0.58 MPa) and a lower limit (for example, 0.57 MPa).
(MPa), the two dry screw compressors 4a and 4b are operated under load or under no load to control the micro pressure.

Further, by changing the order in which the two dry screw compressors 4a and 4b are switched from the load operation state to the no-load operation state by the calendar timer 9, the bias of the no-load operation can be prevented.

In the embodiment of the present invention, the timer 8 and the calendar timer 9 are used as an external circuit of the sequencer 7 to control the control panel 6.
However, the functions of the timer 8 and the calendar timer 9 can be shared by the sequencer 7.

[0021]

As described above, according to the first aspect of the present invention, when two of the low pressure control compressors are in the no-load operation state, one of the number control compressors is stopped after a predetermined time. In addition, by changing the compressor for micropressure control from a no-load operation state to a load operation state, energy loss due to no-load operation can be reduced.

According to the second aspect of the present invention, it is possible to prevent the non-load operation of the micro pressure control compressor from being biased.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a compressor system using a plurality of compressors.

FIG. 2 is a timing chart of an operation method of a plurality of compressors according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Air supply line, 2a, 2b, 2c ... Turbo type compressor, 3a, 3b, 3c, 3d, 3e ... Oil screw type compressor, 4a, 4b ... Dry screw type compressor, 5 ... Pressure sensor, 6 ... Control panel, 7 ...
Sequencer, 8 ... timer, 9 ... calendar timer.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Kunihiko Nagata, Inventor 1500, Hirakawa, Otsu-machi, Kikuchi-gun, Kumamoto Honda Motor Co., Ltd.Kumamoto Factory Co., Ltd. F term in Kumamoto Manufacturing Co., Ltd. (reference) 3H045 AA16 AA26 BA07 BA33 CA03 CA25 CA29 DA01 DA32 DA35 DA39 DA42 DA47 EA13 EA35

Claims (2)

[Claims] A compressor for base operation, a compressor for controlling the number of units, and a compressor for controlling minute pressure are respectively installed in parallel with respect to an air supply line, and the compressor for controlling minute pressure according to a load change of the air supply line. 2
When the vehicle enters the no-load operation state, one of the number control compressors is stopped after a predetermined time, and the micro pressure control compressor is changed from the no-load operation state to the load operation state. How to operate one compressor. 2. The method for operating a plurality of compressors according to claim 1, wherein the order in which the low-pressure control compressor enters a no-load operation state is changed by a calendar timer.