JP2014234744A - Supply pressure control method for compressed-air and supply pressure control system for compressed-air - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize pressure control for compressed air at a supply pipe according to manufacturing items at production facility at a factory and the like.SOLUTION: This method for controlling supply pressure for compressed air comprises the steps for supplying compressed air to be supplied while decreasing its initial supply pressure in a stepwise manner after starting supply of compressed air (steps S3 to S5); and when a control limit alert corresponding to a control limit pressure of compressed air required at production facility (step S5: Yes), supplying the compressed air by returning a set pressure of the compressed air to be supplied to a higher set pressure than the set pressure when the control limit alert is outputted (step S6).

Description

  The present invention relates to a method for managing a supply pressure of compressed air for operating a compressor in a production facility such as a factory and supplying compressed air via a supply pipe, and a supply pressure management system for compressed air.

  Conventionally, in operation where compressed air is supplied via a supply pipe from a compressor that compresses air to a production facility such as a factory, the suction valve of the compressor is opened so that the set pressure on the production facility side is constant. I was controlling the degree. However, in a production facility where various products are produced as production items, the amount of compressed air required may vary from product to product. In some cases, compressed air was sent at a pressure higher than necessary.

  Here, for example, in Patent Document 1, as a technique for operating a compressor in a production facility such as a factory and managing the supply pressure of compressed air that supplies compressed air via a supply pipe, based on the measured pressure value of a pressure sensor. A technique for switching between loading and unloading of a compressor for compressed air is disclosed.

JP 2004-176683 A

However, since the technology described in this document switches between loading and unloading of the compressor for compressed air based on the pressure value measured by the pressure sensor, the production item is a production item in which various products are produced. Accordingly, the pressure setting cannot be changed to an appropriate state.
Therefore, the present invention has been made paying attention to such problems, and it is possible to optimize the pressure management in the compressed air supply piping according to the production items in the production equipment such as a factory. It is an object of the present invention to provide a supply pressure management method and a compressed air supply pressure management system.

  In order to solve the above-described problem, a compressed air supply pressure management method according to one aspect of the present invention operates a compressor that compresses air to supply compressed air to a production facility such as a factory via a supply pipe. A method for managing the supply pressure of compressed air to be supplied, the initial supply pressure setting step for setting an initial supply pressure of compressed air to be supplied to the supply pipe according to a production item in the production facility, and the initial supply An initial compressed air supply step for starting the supply of compressed air at the initial supply pressure set in the pressure setting step; and after the supply of compressed air in the initial compressed air supply step is started, Compressed air decompression supply process to be supplied while gradually decreasing from the initial supply pressure, and when the set pressure of the compressed air is reduced in the compressed air decompression supply process, it is required in the production facility. When a control limit alarm corresponding to the control limit pressure of compressed air is output, the set pressure of the supplied compressed air is returned to a set pressure higher than the set pressure when the control limit alarm is output. And a compressed air pressure supply process for supplying the compressed air.

  In order to solve the above problems, a compressed air supply pressure management system according to an aspect of the present invention operates a compressor that compresses air and compresses it through a supply pipe to production equipment such as a factory that becomes a load. A compressed air supply pressure management system for supplying air, an initial supply pressure setting means for setting an initial supply pressure of compressed air to be supplied to the supply pipe according to a production item in the production facility, and the initial supply Initial compressed air supply means for starting the supply of compressed air at the initial supply pressure set by the pressure setting means; and the compressed air supplied after the supply of compressed air by the initial compressed air supply means is started In the production facility, when the set pressure of the compressed air is reduced by the compressed air reduced pressure supply means to be supplied while being lowered stepwise from the initial supply pressure, When a control limit alarm corresponding to the required control limit pressure of compressed air is output, the set pressure of the supplied compressed air is set higher than the set pressure when the control limit alarm is output. And a compressed air pressure supply means for supplying the compressed air.

  According to the present invention, an initial supply pressure of compressed air to be supplied to the supply pipe is set according to a production item in a production facility, and the compressed air to be supplied is supplied after the supply of the compressed air is started at the initial supply pressure. When the control limit alarm corresponding to the control limit pressure of compressed air required in the production facility is output, the set pressure of the supplied compressed air is managed. Since the pressure is returned to a set pressure higher than the set pressure when the limit alarm is output, the pressure management in the compressed air supply piping can be optimized according to the production items in the production equipment such as a factory.

It is a block diagram explaining one Embodiment of the supply pressure management system which concerns on this invention. It is a flowchart of the pressure control process performed with the supply pressure management system of FIG. It is a graph explaining the example of the transition of the setting pressure of the compressed air which is managed and supplied for every product in a production facility based on the pressure control process of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate. The compressed air supply pressure management system of this embodiment operates a compressor 5 that compresses air and supplies compressed air to the factory 1 via a supply pipe 3 as shown in FIG.
Specifically, as shown in the figure, a compressed air supply pipe 3 is connected to a factory 1 which is a production facility serving as a load. The supply pipe 3 is equipped with a suction valve 4, a compressor 5, a discharge valve 6, a discharge valve 7, a flow meter 8, and a pressure gauge 9 in this order from the air suction side to the factory 1 side. Compressed air can be supplied to actuators and instruments of the equipment, purge air, and other various equipment that need to be supplied with compressed air. When the factory 1 is in operation, for example, the discharge valve 6 is normally closed and the discharge valve 7 is normally open.

  The compressed air supply pressure management system of the present embodiment includes a process control computer (PC) 2 and a pressure control device (DCS) 10. The process control computer 2 is mutually connected to each control device including the factory 1 through a network capable of data communication. The process control computer 2 collects, analyzes, and calculates production information as needed, and as a host computer, the entire factory 1 Control the running process. In this example, the factory 1 is connected to be able to exchange necessary data via the signal line 24, and the pressure control device 10 is connected to be able to exchange necessary data via the signal line 21. Yes. Further, the pressure control device 10 can receive the measurement data from the pressure gauge 9 via the signal line 22 and is connected to the factory 1 via the signal line 23, which is necessary in the factory 1. A control limit alarm corresponding to the control limit pressure of compressed air is acquired.

  Here, the pressure control device 10 transmits and receives necessary signals through the signal lines 20 to 24 under the monitoring of the process control computer 2 to control the compressed air supply pressure supplied to the factory 1. . In this example, the pressure control device 10 receives measurement data from the pressure gauge 9, controls the opening of the suction valve 4 and the drive of the compressor 5 based on a predetermined pressure control process (described later), and supplies the supply pipe. The supply pressure of the compressed air supplied from 3 is controlled to be a predetermined pressure.

Hereinafter, the pressure control process executed by the pressure control apparatus 10 will be described.
When the pressure control process is executed by the pressure control apparatus 10, as shown in FIG. 2, first, the process proceeds to step S1, and the product information currently produced in the factory 1 (that is, production) from the process control computer 2 Item). In subsequent step S2, an initial supply pressure of compressed air set in advance corresponding to the product information is set according to the acquired product information. Then, by constantly monitoring the measurement data from the pressure gauge 9 by feedback control, the supply control of the compressed air to the supply pipe 3 is started so that the measurement data of the pressure gauge 9 becomes the initial supply pressure. The supply control of the compressed air is performed by controlling the opening degree of the suction valve 4 via the signal line 20.

  In the following step S3, it is monitored whether or not a predetermined time has elapsed. If the predetermined time has elapsed (Yes), the process proceeds to step S4. If not (No), the process waits in step S3. In step S4, the current set pressure is lowered by a predetermined amount to a new set pressure by reducing the opening of the suction valve 4, and the compressed air is supplied to the supply pipe 3 by the feedback control so as to become the new set pressure. Supply is continued and it transfers to step S5. In step S5, the presence or absence of the control limit alarm from the factory 1 side is monitored. If the control limit alarm is output (Yes), the process proceeds to step S6. If not (No), the process returns to step S3. . On the other hand, in step S6, the set pressure is increased by a predetermined amount by opening the opening of the suction valve 4, and the process returns to step S5. Here, “control limit alarm” refers to management of compressed air required in actuators and control equipment of facilities in the factory 1, compressed air for purging, and other various facilities that require supply of compressed air. A signal such as an alarm set according to the limit pressure is used.

  In the example of the compressed air supply pressure management system of the present embodiment, the “initial supply pressure setting means (process)” described in “Means for Solving the Problems” corresponds to Steps S1 and S2. The “compressed air decompression supply means (process)” corresponds to the steps S3 and S4 to S5 (No), and the “compressed air pressure increase supply means (process)” corresponds to the steps S5 (Yes) to S6. It corresponds.

  Next, the operation of the above-described supply pressure management system (that is, the compressed air supply pressure management method according to the present invention) and the operation and effect thereof will be described. By the way, in the said factory 1, when various products (for example, products AC) are produced, the quantity of compressed air consumed by each product may differ. Therefore, in the present embodiment, an example of two products A and B having different amounts of compressed air consumed will be described with reference to FIG.

Now, when the product A is produced in the factory 1, product information that the current production item in the factory 1 is the product A is sent to the process control computer 2 via the signal line 24. At the same time, the pressure control device 10 acquires product information that the current production item is the product A via the signal line 21 (step S1). Since the acquired product information is the product A, the pressure control device 10 sets an initial supply pressure corresponding to the product A (step S2). In the example shown in FIG. 3, the initial supply pressure P _A1 corresponding to the product A is 4.50 (kgf / cm ² ). The pressure control device 10 monitors the measurement data from the pressure gauge 9 via the signal line 22, controls the opening degree of the suction valve 4 via the signal line 20, and supplies compressed air supplied from the supply pipe 3. The pressure control is performed so that the supply pressure becomes the initial supply pressure _PA1 (step S2).

After the supply pressure is set to the initial supply pressure _PA1 , the pressure control device 10 monitors whether or not a predetermined time has elapsed by a timer function, and decreases the set pressure by a predetermined amount every time the predetermined time elapses. Use a new set pressure. In the example shown in FIG. 3, the predetermined lowering width corresponding to the product A is 0.05 (kgf / cm ² ). Then, while monitoring the measurement data from the pressure gauge 9 via the signal line 22 at this new set pressure, the opening degree of the suction valve 4 is controlled via the signal line 20 and supplied from the supply pipe 3. Pressure control is performed so that the supply pressure of the compressed air becomes the new set pressure (steps S3, S4 to S5 (No)). Thereby, in the example shown in FIG. 3, the set pressure is gradually lowered from the initial supply pressure P _A1 of the product A to P _A2 → P _A3 → P _A4 step by step.

On the other hand, the pressure controller 10 monitors the presence or absence of the control limit alarm substantially in parallel with the process of lowering the set pressure by a predetermined amount (step S5). If the control limit alarm is output from the factory 1 side, the set pressure is increased by a predetermined amount (step S6). In the example shown in FIG. 3, since the control limit alarm K is output at the stage of the set pressure P _A4 (4.35 (kgf / cm ² )), in this example, the set pressure is set by a predetermined amount rather than the current set pressure P _A4. increase the setting pressure set pressure _{P A3} of higher stage front (i.e., the predetermined gains is 0.05 in this example (kgf / ^cm 2)), at the new set pressure _{P A4,} through the signal line 22 While monitoring the measurement data from the pressure gauge 9, the opening of the suction valve 4 is controlled via the signal line 20 so that the supply pressure of the compressed air supplied from the supply pipe 3 becomes the new set pressure. Perform pressure control.

Thereafter, the above process is repeated, and in the example shown in FIG. 3, the set pressures P _A3 and P _A4 are alternately and repeatedly set. Similarly, in another example shown in FIG. 3, the initial supply pressure P _B1 corresponding to the product B is 4.40 (kgf / cm ² ), and the predetermined increase / decrease width is 0.05 (kgf / cm ² ). ). Note that the execution content of the pressure control process and the example of the transition of the set pressure of the set pressures P _{B1 to} P _B4 shown in the figure are the same as the example of the product A, and therefore the description corresponding to the product B is omitted.

  As described above, according to the supply pressure management system of the present embodiment, the initial supply pressure of the compressed air supplied to the supply pipe 3 is set according to the production item in the factory 1, and the supply of the compressed air is started. The compressed air to be supplied is supplied when the supplied compressed air is gradually lowered from the initial supply pressure and a control limit alarm corresponding to the control limit pressure of the compressed air required in the factory 1 is output. Since the set pressure of the air is supplied back to the set pressure one stage before the set pressure when the control limit alarm is output, the pressure in the compressed air supply pipe 3 according to the production item of the factory 1 Management can be optimized. Therefore, the discharge pressure of the compressor 5 can be reduced to save power.

  The compressed air supply pressure management method according to the present invention and the compressed air supply pressure management system according to the present invention are not limited to the above-described embodiments, and various methods can be used without departing from the spirit of the present invention. Can be modified. For example, in the above-described embodiment, the example in which the pressure control process is executed by the pressure control device 10 has been described. However, the present invention is not limited to this, and various types of the supply pressure management system can be configured as long as the pressure control process can be executed. Can be used.

In the above-described embodiment, the example in which the predetermined lowering or raising width of the set pressure corresponding to the product is 0.05 (kgf / cm ² ) has been described based on the example of FIG. Instead, the predetermined decrease or increase of the set pressure can be set to an appropriate value. Further, the predetermined lowering or increasing width of the set pressure may be a constant width or may be gradually increased or decreased by a predetermined arithmetic expression. For example, the present set pressure can be multiplied by a predetermined ratio (for example, X%), and the amount of decrease or increase can be set to the predetermined ratio. In the above-described embodiment, the example in which the predetermined lowering range and the increasing range of the set pressure are the same value has been described. However, the present invention is not limited to this, and the values may be set to different values.

1 factory (production equipment)
2 Process control computer (PC)
3 Supply piping 4 Suction valve 5 Compressor 6 Air discharge valve 7 Discharge valve 8 Flow meter 9 Pressure gauge 10 Pressure control device (DCS)
20-24 Signal line K Control limit alarm

Claims (2)

A method for managing a supply pressure of compressed air that operates a compressor that compresses air and supplies compressed air to a production facility serving as a load via a supply pipe,
An initial supply pressure setting step for setting an initial supply pressure of compressed air to be supplied to the supply pipe according to a production item in the production facility;
An initial compressed air supply step for starting the supply of compressed air at the initial supply pressure set in the initial supply pressure setting step;
A compressed air decompression supply step for supplying the compressed air to be supplied while being gradually lowered from the initial supply pressure after the supply of the compressed air is started in the initial compressed air supply step;
Supplied when the control limit alarm corresponding to the control limit pressure of compressed air required in the production facility is output when the set pressure of compressed air is reduced in the compressed air decompression supply step A compressed air supply pressure management method, comprising: a compressed air pressure increasing supply step for supplying a set pressure of compressed air to a set pressure higher than the set pressure when the control limit alarm is output. A compressed air supply pressure management system that operates a compressor that compresses air and supplies compressed air to a production facility serving as a load via a supply pipe,
Initial supply pressure setting means for setting an initial supply pressure of compressed air to be supplied to the supply pipe in accordance with the production item in the production facility;
Initial compressed air supply means for starting supply of compressed air at the initial supply pressure set by the initial supply pressure setting means;
Compressed air decompression supply means for supplying the compressed air to be supplied in a stepwise manner from the initial supply pressure after the supply of compressed air is started by the initial compressed air supply means;
Supplied when a control limit alarm corresponding to the control limit pressure of compressed air required in the production facility is output when the set pressure of compressed air is reduced by the compressed air decompression supply means A compressed air supply pressure management system comprising compressed air pressure increase supply means for supplying a set pressure of compressed air back to a set pressure higher than the set pressure when the control limit alarm is output.

Images