JP3404492B2 - Compressor operation control method and compressor operation control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor operation control method and a compressor for controlling the operation of a plurality of compressors, collecting discharge air from the compressors in an air tank, and supplying the compressed air as a compressed air source in a predetermined pressure range. The present invention relates to improvement of a machine operation control device.

[0002]

2. Description of the Related Art A compressor operation control device for controlling the operation of a plurality of compressors, collecting discharge air from the compressors in an air tank, and supplying the compressed air as a compressed air source in a predetermined pressure range is shown in FIG.
It is used in a compressed air supply device as shown in FIG. In this compressed air supply device, the discharge air of the six compressors 1 to 6 from No. 1 to No. 6 is once supplied to the air tank 7 through the air pipe 9.
The compressed air that has been collectively stored in the air tank 7 and is stored in the air tank 7 is supplied to the factory equipment 21 and the like for power, instruments and chores. In the compressors 1 to 6, the pressure of the compressed air in the air tank 7 is
As shown in FIG. 9A, for example, 6.0 to 6.4 kg /
The operation is intermittently controlled so as to be within a predetermined range of cm ² .

This operation control is performed based on the pressure in the air tank 7 detected by the pressure sensor 11 through the pressure extraction valve 13, the pressure extraction pipe 8 and the instrument pipe 14.
The pressure value detected by the pressure sensor 11 is given to the compressor operation control device 12 in the same control panel 10. The compressor operation control device 12 starts, loads (sends out air), and unloads (sends air even though the compressor is in operation) so that the given pressure value falls within the above-mentioned predetermined range. The operation is controlled according to a predetermined order, either "no" or stopped.

FIG. 8 is a flow chart showing the operation of the conventional compressor operation control device 12 in the case of controlling the start of the compressor. The compressor operation control device 12 reads the pressure value in the air tank 7 detected by the pressure sensor 11 (S20), and determines the lower limit allowable value 6.0 of the predetermined pressure range of the compressed air in the air tank 7.
A set value of 6.1 kg / cm that allows for a margin of kg / cm ^2.
It is compared with ² (S22). As a result, when the read pressure value is less than the set value, one of the stopped compressors is started according to the order (however, when there is no compressor being unloaded) and the timer is started. (S24).

This timer is for measuring the time required from the start of the compressor to the time when it can be loaded. When the timer measures the time (S26), the loading of the compressor is started. (S28). The compressor operation control device 12 compares the read pressure value and the set value,
If the read pressure value is not less than the set value (S2
2) Next, read the sampled pressure value (S2
0).

[0006]

In the compressed air supply apparatus having a plurality of compressors as described above, it is preferable that the capacity of the motor of the compressor is large in order to achieve an energy saving effect. The motor start-up must be star / delta start-up, which is time consuming. Further, in the compressor, loading is performed in a state where the motor can be operated under full load. Therefore, it takes, for example, 15 to 30 seconds from the start of the compressor to the state where air can be discharged.

However, as shown in FIG.
If the pressure drop of compressed air in the tank changes slowly, compress it.
Time from when the machine starts up until when air can be discharged
Lower limit value 6.0 kg / cm²Below
However, if the pressure drop changes rapidly, the lower limit
Significantly interrupt the allowable value (for example, 5.8 kg / cm ²
The air supply may be hindered. The present invention
Is made in view of the above-mentioned circumstances,
Stable regardless of the speed of pressure drop of compressed air in the air tank
Compressor operation control method and compressor operation capable of supplying stable air
An object is to provide a rolling control device.

[0008]

In the compressor operation control method and the compressor operation control apparatus according to the present invention, as shown in FIG. 7, a pressure change (line segments a, b) within a predetermined time in the air tank.
Of the air pressure), predicting the time when the pressure in the air tank reaches the lower limit (6.0 kg / cm ² ) of the predetermined pressure range, When it is shorter than the time ta that allows a sufficient time until the state becomes possible, the stopped compressor is started. Time ta
The allowance of is determined in consideration of the sampling cycle of pressure change.

In the compressor operation control method according to the first aspect of the present invention, each of a plurality of compressors is started / stopped, and the discharge air of the compressors is collected in an air tank and supplied as a compressed air source in a predetermined pressure range. In the compressor operation control method for calculating the pressure change in the air tank per predetermined time, the time in which the pressure in the air tank reaches the lower limit of the predetermined pressure range by the calculated pressure change per predetermined time Is predicted, and when the predicted time is shorter than a predetermined time, the stopped compressor is activated.

In the compressor operation control method according to the second aspect of the present invention, the predetermined time period is longer than the time period from the start of the stopped compressor to the discharge of air. Characterize.

A compressor operation control device according to a third aspect of the present invention starts / stops each of a plurality of compressors, collects discharge air of the compressors in an air tank, and supplies the compressed air as a compressed air source in a predetermined pressure range. In the compressor operation control device for calculating the pressure change in the air tank for a predetermined time, the pressure in the air tank is changed to the predetermined pressure range by the pressure change for a predetermined time calculated by the means. Means for calculating and predicting the time to reach the lower limit of, and means for comparing the time calculated and predicted by the means with a predetermined time, and stopping when the comparison result of the means is shorter than the predetermined time Means for activating the compressor therein.

In the compressor operation control method according to the first aspect of the invention and the compressor operation control device according to the third aspect of the invention, the calculating means calculates the pressure change per predetermined time in the air tank, and calculates and predicts the change. Based on the calculated pressure change per predetermined time, the time for the pressure in the air tank to reach the lower limit of the predetermined pressure range is calculated and predicted. The comparing means compares the operation-predicted time with a predetermined time, and when the comparison result indicates that the operation-predicted time is shorter than the predetermined time, the activating means activates the stopped compressor. With this, the pressure in the air tank does not become lower than the lower limit of the predetermined pressure range, regardless of whether the pressure of the compressed air in the air tank gradually decreases or decreases.
A stable air supply can be performed.

A compressor operation control device according to a fourth aspect of the present invention controls the operation of each of the plurality of compressors according to a predetermined order to either discharge air during operation, not discharge air during operation, or stop. In a compressor operation control device for collecting the discharge air of the compressor in an air tank and supplying it as a compressed air source in a predetermined pressure range, means for determining the presence or absence of a compressor that is not discharging air during operation, When there is no means,
A means for calculating a pressure change per predetermined time in the air tank, and a time when the pressure in the air tank reaches a lower limit of the predetermined pressure range is calculated and predicted by the pressure change per predetermined time calculated by the means. Means for comparing the time predicted by the means with a predetermined time, and a comparison result of the means when the time predicted for the calculation is shorter than the predetermined time according to the predetermined order. Means for ejecting air after the machine is started.

In the compressor operation control device according to the fourth invention,
The judging means judges the presence or absence of the compressor that is not discharging air during operation, and when the judging means judges that there is no compressor, the calculating means calculates the pressure change in the air tank per predetermined time. The calculation and prediction means calculates and predicts the time for the pressure in the air tank to reach the lower limit of the predetermined pressure range based on the calculated pressure change per predetermined time. The means to compare is
The calculated predicted time is compared with a predetermined time, and when the comparison result is that the calculated predicted time is shorter than the predetermined time,
According to a predetermined order, the means for performing the operation causes the compressor that is stopped to be activated, and then causes the air to be discharged. As a result, the pressure in the air tank does not become lower than the lower limit of the predetermined pressure range, and stable air supply can be performed irrespective of the gradual decrease in the pressure of the compressed air in the air tank.

In the compressor operation control device according to the fifth aspect of the present invention, the predetermined time period is longer than the time period from the start of the stopped compressor to the discharge of air. Characterize.

In the compressor operation control method according to the second aspect of the invention and the compressor operation control device according to the fifth aspect of the invention, for a predetermined time, it is possible to discharge air after the stopped compressor is activated. Since it is longer than the time of, the newly started compressor can start discharging air before the pressure in the air tank becomes lower than the lower limit of the predetermined pressure range. A stable air supply can be performed regardless of the speed of decrease.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing the embodiments thereof. FIG. 1 is a block diagram showing a configuration of a compressed air supply device using an embodiment of a compressor operation control method and a compressor operation control device according to the present invention. In this compressed air supply device, the discharge air of the six compressors 1 to 6 from No. 1 to No. 6 is temporarily stored together in the air tank 7 by the air pipe 9, and the compressed air stored in the air tank 7 is It is supplied to the factory equipment 21, etc. for power, instruments, and chores. Each of the compressors 1 to 6 is intermittently controlled so that the pressure of the compressed air in the air tank 7 falls between the upper limit value H and the lower limit value L of a predetermined range, as shown in FIG. .

This operation control is performed based on the pressure in the air tank 7 detected by the pressure sensor 11 through the pressure extraction valve 13, the pressure extraction pipe 8 and the instrument pipe 14.
The pressure value detected by the pressure sensor 11 is given to the compressor operation control device 12a according to the present invention, which is in the same control panel 10. The compressor operation control device 12a starts, loads (sends air), and unloads (sends air while operating) the compressors 1 to 6 so that the given pressure value falls within the predetermined range described above. The operation is controlled according to a predetermined order, either "no" or stopped.

FIG. 2 is a block diagram showing the configuration of an embodiment of the compressor operation control device 12a according to the present invention. The compressor operation control device 12a outputs / inputs a CPU 18 of a microcomputer, a timer 20 started / stopped by the CPU 18, and operation control signals / monitoring signals between the CPU 18 and the compressors 1-6. CPU 18
Connected to the I / O port 16 of
An operating unit 19 for an operator to perform various settings, alarm stop / reset, and manual operation, and a display unit 17 connected to the I / O port 16 for displaying and outputting various settings, operation contents, alarms, and the like. , The analog current signal of, for example, 4 to 20 mA output according to the pressure in the air tank 7 detected by the pressure sensor 11 is converted into a digital signal, and the I / O port 16
And an A / D converter 15 for inputting to the.

The operation of the compressor operation control device 12a having such a configuration to control the operation of the compressors 1 to 6 will be described below. The set pressure in the air tank 7 when the compressor operation control device 12a controls the operation of the compressors 1 to 6 is set as shown in FIG. 3, for example. The normal operating range H level to L level in the air tank 7 has a width of 0.2 kg / cm ² .
A normal control range is between an HH level 0.1 kg / cm ² above the H level and an LL level 0.1 kg / cm ² below the L level. 0.3 from HH level and HH level
between 0.3 kg / cm ² less LLL levels than during and LL level and LL level with kg / cm ² higher HHH level is an emergency control range, the pressure in the air tank 7 is HHH
The upper limit alarm is output when the level is reached, and the lower limit alarm is output when the LLL level is reached.

In the normal operation range H level to L level in the air tank 7, the compressor operation control device 12a, when the pressure rises and reaches the H level as shown in FIG. 4, for example, the compressor being loaded. Then, one is unloaded according to a predetermined order. On the other hand, when the pressure drops and reaches the L level, one compressor is loaded from the unloading compressor in a predetermined order. However, when the pressure rises and reaches the H level when one or more compressors are unloaded, one of them is unloaded according to a predetermined order from the compressor being loaded. Stop the main engine (scheduled to stop). When there is no compressor being unloaded, the time to reach the L level is calculated and predicted from the calculated pressure change per predetermined time, and a predetermined order is given from the compressor being loaded so as not to reach the L level. According to
Load one after starting one.

FIG. 5 is a flow chart showing the operation of the compressor operation control device 12a when controlling the start-up of the compressor. The compressor operation control device 12a determines whether or not there is a compressor that is being unloaded (S1), and when it is determined that there is a compressor that is being unloaded, returns and executes another control operation. . When the compressor operation control device 12a determines that the unloading compressor does not exist (S
1), a predetermined number of pressure values in the air tank 7 detected by the pressure sensor 11 are read (S2, S4), and the pressure change per predetermined time is calculated (S6).

At this time, for example, as shown in FIG. 6, reading (sampling) of the pressure value is performed 5 times every 0.2 seconds, and 1.0 second (predetermined time) of the average of the pressure change is calculated. . In other words, the read pressure values are read in the order A,
Assuming B, C, D, and E, (((A−B) + (B−C) + (C−D) + (D−
E)) / 0.2) / 5 = AE, which is the same as calculating the pressure change by sampling every 1.0 seconds. It should be noted that 1.0 second of pressure change (pressure change / second) may be calculated every 0.2 second.

Next, the compressor operation control device 12a calculates the time for reaching the lower limit allowable value L level of the normal operation range by the calculated pressure change per 1.0 second (S6) (S8). At this time, (E−L) / (A−E) is calculated (S8), and as shown in FIG. 6, (E−L) / (A−E)
When ≦ ta (seconds) (S10), one of the stopped compressors is started and the timer is started (S12) according to a predetermined order. ta is a time allowed for the time from the start of the stopped compressor to the time when it is possible to discharge (load) air.

The compressor operation control device 12a causes the timer to measure a predetermined time from the start of the stopped compressor until the load becomes possible (S1).
4) The compressor is loaded (S16). The compressor operation control device 12a calculates (E−L) / (A−E) (S8), and when (E−L) / (A−E)> ta, or (E−L) / (A). When −E) <0 (when the pressure is negative, the pressure is increasing), the process returns (S10).

Here, for example, ta; 10 seconds, E; 6.
^{1kg / cm 2, A; 6.11kg} / cm 2, L; 6.
At 0 kg / cm ² , (6.1-6.0) / (6.11-6.1) = 10 (=
ta) and start the compressor. On the other hand, for example, ta;
10 seconds, E; 6.15 kg / cm ² , A; 6.16 kg
/ Cm ^2, L; when ^{6.0kg / cm 2, (6.15-6.0)} / (6.16-6.15) = 15
(> Ta) and the compressor is not started.

[0027]

According to the compressor operation control method of the first invention and the compressor operation control device of the third and fourth inventions, the pressure in the air tank does not become lower than the lower limit of the predetermined pressure range. Regardless of the speed of pressure drop of compressed air in the air tank,
A stable air supply can be performed.

According to the compressor operation control method of the second aspect of the invention and the compressor operation control device of the fifth aspect of the invention, the newly activated compression is performed before the pressure in the air tank becomes lower than the lower limit of the predetermined pressure range. The machine can start discharging air, and a stable air supply can be performed regardless of the speed of the pressure drop of the compressed air in the air tank.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a compressed air supply device.

FIG. 2 is a block diagram showing a configuration of an embodiment of a compressor operation control device according to the present invention.

FIG. 3 is an explanatory diagram for explaining a set pressure in the air tank when the compressor operation control device according to the present invention controls the operation of the compressor.

FIG. 4 is an explanatory diagram for explaining an operation of controlling the operation of the compressor by the compressor operation control device according to the present invention.

FIG. 5 is a flowchart showing an operation when the compressor operation control device according to the present invention controls startup of the compressor.

FIG. 6 is an explanatory diagram for explaining the operation of the compressor operation control device according to the present invention.

FIG. 7 is an explanatory diagram for explaining the operation of the compressor operation control device according to the present invention.

FIG. 8 is a flowchart showing an operation when a conventional compressor operation control device controls startup of a compressor.

FIG. 9 is an explanatory diagram for explaining the operation of the conventional compressor operation control device for controlling the operation of the compressor.

[Explanation of symbols]

1-6 compressor 7 air tank 11 Pressure sensor 12a Compressor operation control device 16 I / O ports 18 CPU

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP 10-30574 (JP, A) JP 6-249190 (JP, A) JP 61-112788 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) F04B 49/06

Claims (5)

(57) [Claims] 1. A compressor operation control method for starting / stopping each of a plurality of compressors, collecting discharge air of the compressors in an air tank, and supplying the compressed air as a compressed air source in a predetermined pressure range, The pressure change per predetermined time in the air tank is calculated, and the time when the pressure inside the air tank reaches the lower limit of the predetermined pressure range is calculated and predicted by the calculated pressure change per predetermined time, and the calculated and predicted time is calculated. A compressor operation control method, which starts a stopped compressor when the time is shorter than a predetermined time. 2. The compressor operation control method according to claim 1, wherein the predetermined time period is longer than a time period from when the stopped compressor is started to when air can be discharged. 3. A compressor operation control device for starting / stopping each of a plurality of compressors, collecting discharge air from the compressors in an air tank, and supplying the compressed air as a compressed air source in a predetermined pressure range, A means for calculating a pressure change within a predetermined time in the air tank, and a time when the pressure in the air tank reaches the lower limit of the predetermined pressure range is calculated and predicted by the pressure change per predetermined time calculated by the means. Means, means for comparing the operation-predicted time with the predetermined time, and means for activating the stopped compressor when the comparison result of the means is shorter than the predetermined time for the operation-predicted time. A compressor operation control device comprising: 4. The operation control of each of the plurality of compressors is performed according to a predetermined order to either discharge air during operation, non-discharge air during operation, or stop, and discharge air from the compressor into an air tank. In summary, in a compressor operation control device for supplying as a compressed air source in a predetermined pressure range, means for determining the presence or absence of a compressor that is not discharging air during operation, and when the means determines that there is no A means for calculating a pressure change within a predetermined time in the air tank, and a time when the pressure in the air tank reaches the lower limit of the predetermined pressure range is calculated and predicted by the pressure change per predetermined time calculated by the means. And a means for comparing the operation-predicted time by the means with a predetermined time, and when the comparison result of the means is shorter than the predetermined time for the operation-predicted time, the compressor being stopped according to the predetermined order. After launching Compressor operation control apparatus characterized by comprising: means for causing the air discharge. 5. The compressor operation control device according to claim 3, wherein the predetermined time period is longer than a time period from when the stopped compressor is activated until air can be discharged. .