JP7568565B2 - Gas Compression System - Google Patents

Description

The present invention relates to a gas compression system equipped with a number control device that controls the number of operating compressors.

Patent Document 1 discloses a gas compression system that includes multiple compressors, a storage tank that stores compressed gas (more specifically, compressed air) discharged from the multiple compressors, a pressure sensor that detects the pressure in the storage tank, and a number control device that controls the number of operating compressors based on the pressure detected by the pressure sensor.

The number-of-compressors control device in Patent Document 1 selects the compressors to operate so that the cumulative operating time of each of the multiple compressors is equalized.

JP 2014-152698 A

In the above conventional technology, the cumulative operating time of each of the multiple compressors is averaged. Therefore, the cumulative operating time of each of the multiple compressors reaches the specified maintenance time at the same time, and maintenance of the multiple compressors is performed simultaneously.

On the other hand, there is a need to discretize the cumulative operating time of each of the multiple compressors for reasons such as wanting to avoid concentration of maintenance timing and maintenance costs. Therefore, it is conceivable that the unit count control device performs control to select the compressor to be operated so that when the cumulative operating time of one of the multiple compressors reaches a predetermined maintenance time, the cumulative operating time of each of the multiple compressors is shifted by a target difference. The aforementioned target difference is conceivably set by a user interface. However, depending on the operating status of the system, it may not be possible to realize the target difference set by the user interface. This may cause problems with the maintenance plan.

The present invention was made in consideration of the above, and one of its objectives is to estimate whether a set target difference in cumulative driving time is achievable.

In order to solve the above problem, the configuration described in the claims is applied. The present invention includes a number of means for solving the above problem, and an example thereof is a gas compression system that includes a number of compressors, a number control device that controls the number of operating compressors and acquires the operating time of each of the multiple compressors, and a user interface that sets a target difference when discretizing the cumulative operating time of each of the multiple compressors, and the number control device controls the selection of a compressor to be operated so that the cumulative operating time of each of the multiple compressors is leveled during a predetermined period set in advance, and then controls the selection of a compressor to be operated so that the cumulative operating time of each of the multiple compressors shifts by the target difference when the cumulative operating time of one of the multiple compressors reaches a predetermined maintenance time. When the predetermined period has elapsed, the number control device calculates an upper limit value of the target difference based on the operating time of each of the multiple compressors and the operating time of the number control device during the predetermined period, determines whether the target difference set in the user interface is equal to or less than the upper limit value, and notifies the user interface of the fact when the target difference set in the user interface exceeds the upper limit value.

According to the present invention, it is possible to estimate whether the set target difference in cumulative driving time is achievable.

Further issues, configurations and effects other than those mentioned above will become clear in the explanation below.

1 is a schematic diagram illustrating a configuration of a gas compression system according to an embodiment of the present invention. 4 is a flowchart showing the number of units controlled by the number of units control device according to one embodiment of the present invention. 4 is a flowchart showing a target difference determination control of the vehicle count control device according to an embodiment of the present invention. FIG. 4 is a diagram showing a specific example of a change in cumulative operation time of each compressor in the embodiment of the present invention. FIG. 11 is a diagram showing a specific example of a change in cumulative operation time of each compressor in one modified example of the present invention.

One embodiment of the present invention will be described with reference to the drawings.

Figure 1 is a schematic diagram showing the configuration of a gas compression system in this embodiment.

The gas compression system of this embodiment includes three compressors 1A, 1B, and 1C, and a storage tank 2 that stores compressed gas (more specifically, compressed air, for example) discharged from the compressors 1A, 1B, and 1C, and supplies the compressed gas from the storage tank 2 to a production line (not shown) via an extraction valve 3 and a supply pipe 4.

The gas compression system of this embodiment also includes a pressure sensor 5 that detects the pressure in the storage tank 2, a number control device 6 that controls the number of operating compressors based on the pressure detected by the pressure sensor 5, a user interface 7 connected to the number control device 6, and a wired or wireless communication network 8 that connects the compressors 1A, 1B, and 1C and the number control device 6 so that they can communicate with each other.

Although the details of the unit count control device 6 are not shown, it has, for example, a memory that stores programs and settings, a processor that executes processing based on the programs and settings, and a communication interface that is interposed between the processor and the communication network 8. The user interface 7 is, for example, an external terminal such as a smartphone that can communicate with the unit count control device 6 via wired or wireless communication, or a touch panel integrated with the unit count control device 6. The user interface 7 displays information about the compressors 1A, 1B, and 1C acquired via the communication network 8, and allows the user to input settings.

Compressor 1A includes a compressor body 9A that compresses gas (more specifically, for example, air), a motor 10A that drives compressor body 9A, a control unit 11A that controls motor 10A in response to commands from, for example, a unit count control device 6, and thus controls compressor body 9A, a tank 13A that is provided on the discharge side of compressor body 9A and connected to storage tank 2 via piping 12, a pressure sensor 14A that detects the pressure in tank 13A, and a user interface (more specifically, for example, a display and a push button) (not shown). Note that the pressure detected by pressure sensor 14A is approximately the same as the pressure detected by pressure sensor 5.

Although the details of the control unit 11A are not shown, it has, for example, a memory that stores programs and settings, a processor that executes processing based on the programs and settings, and a communication interface that is interposed between the processor and the communication network 8. The user interface displays information about the compressor 1A and allows the user to input settings.

Compressors 1B and 1C have the same configuration as compressor 1A. That is, compressor 1B includes a compressor body 9B, a motor 10B, a control unit 11B, a tank 13B, a pressure sensor 14B, and a user interface. Compressor 1C includes a compressor body 9C, a motor 10C, a control unit 11C, a tank 13C, a pressure sensor 14C, and a user interface.

The details of the number control of the number control device 6 are explained using Figure 2. Figure 2 is a flowchart showing the number control of the number control device in this embodiment.

The number of compressors control device 6 controls the number of operating compressors so that the pressure detected by the pressure sensor 5 is within a predetermined range. More specifically, the number of compressors control device 6 determines whether the pressure detected by the pressure sensor 5 has risen to a preset upper limit value Pu (step S1). If the pressure detected by the pressure sensor 5 has risen to the upper limit value Pu, it outputs a command to stop one of the compressors that is in operation. The compressor control unit stops the compressor body in response to the aforementioned stop command. This reduces the number of operating compressors (step S2).

The number control device 6 determines whether the pressure detected by the pressure sensor 5 has fallen to a preset lower limit value Pd (where Pd<Pu) (step S3). Then, when the pressure detected by the pressure sensor 5 has fallen to the lower limit value Pd, it outputs a command to drive one of the stopped compressors. The compressor control unit drives the compressor body in response to the aforementioned drive command. This increases the number of operating compressors (step S4).

The unit count control device 6 performs the unit count control described above, and also uses a timer to obtain the operating time of compressor 1A (more specifically, the operating time of compressor body 9A), the operating time of compressor 1B (more specifically, the operating time of compressor body 9B), the operating time of compressor 1C (more specifically, the operating time of compressor body 9C), and the operating time of the unit count control device 6 (more specifically, the time that at least one compressor body is in an operating state, in other words, the operating time of the system).

The number control device 6 performs control to select a compressor so that the cumulative operating time of compressor A, the cumulative operating time of compressor 1B, and the cumulative operating time of compressor 1C are leveled out in a predetermined period (for example, one year). Then, after the predetermined period has elapsed, the control shifts to control to select a compressor so that the cumulative operating time of compressor A1, the cumulative operating time of compressor 1B, and the cumulative operating time of compressor 1C are discretized. In detail, if the priority order is set in the order of compressors 1A, 1B, and 1C, for example, when the cumulative operating time of compressor 1A reaches a predetermined maintenance time Tmc, the control shifts to control to select a compressor so that the difference between the cumulative operating time of compressor 1A and the cumulative operating time of compressor 1B becomes the target difference ΔT, and the difference between the cumulative operating time of compressor 1B and the cumulative operating time of compressor 1C becomes the target difference ΔT. The above-mentioned target difference ΔT and priority order are set by the user interface 7 before or immediately after the predetermined period has elapsed.

Here, the most significant feature of this embodiment is that when a predetermined period has elapsed, the number of units control device 6 calculates an upper limit value ΔTmax of the target difference based on the operating time T1 of compressor 1A, the operating time T2 of compressor 1B, the operating time T3 of compressor 1C, and the operating time Tb of the number of units control device 6 during the predetermined period (see equations (1) and (2) below).
ΔTmax={(Tmc×n-(T1+T2+...+Tn))×(1-L)}/(1+2+...+(n-1))...(1)
L=(T1+T2+...+Tn)/(n×Tb)...(2)

The above formula (1) is derived by assuming that one of n compressors (n=3 in this embodiment) is operated continuously until its cumulative operating time reaches a predetermined maintenance time Tmc. L in formula (1) is the load factor of the system, and is expressed by formula (2).

The number control device 6 determines whether the set target difference ΔT is achievable based on whether the target difference ΔT set in the user interface 7 is equal to or less than the upper limit value ΔTmax. If the target difference ΔT exceeds the upper limit value ΔTmax, the user interface 7 notifies the user of this. Details of this target difference determination control will be described with reference to FIG. 3.

Figure 3 is a flowchart showing the target difference determination control of the number of vehicles control device in this embodiment.

The number control device 6 controls the selection of compressors so that the cumulative operating time of compressor A, the cumulative operating time of compressor 1B, and the cumulative operating time of compressor 1C are equalized until a predetermined period of time (e.g., one year) has elapsed (step S11).

When a predetermined period has elapsed, the number control device 6 calculates the upper limit value ΔTmax of the target difference based on the operating time T1 of compressor 1A, the operating time T2 of compressor 1B, the operating time T3 of compressor 1C, and the operating time Tb of the number control device 6 during the predetermined period (step S13). Then, depending on whether the target difference ΔT set by the user interface 7 is equal to or smaller than the upper limit value ΔTmax, it is determined whether the set target difference ΔT is achievable (step S14).

When the target difference ΔT set in the user interface 7 is equal to or less than the upper limit value ΔTmax (i.e., when the set target difference ΔT is achievable), the number control device 6 transitions to control for selecting a compressor so that the cumulative operating time of compressor A1, the cumulative operating time of compressor 1B, and the cumulative operating time of compressor 1C are discretized (step S15).

When the target difference ΔT set in the user interface 7 exceeds the upper limit value ΔTmax, the number of units control device 6 displays a confirmation screen (not shown) on the user interface 7 (step S16). This confirmation screen is for confirming with the user whether or not it is OK to correct the target difference ΔT to the upper limit value ΔTmax, and, if not, for confirming with the user whether or not it is OK to continue the control for leveling out the cumulative operating times of the compressors 1A, 1B, and 1C.

When a command to correct the target difference ΔT to the upper limit value ΔTmax is input via the user interface 7, the number control device 6 corrects the target difference ΔT to the upper limit value ΔTmax (step S18). After that, the control proceeds to control for selecting a compressor so that the cumulative operating time of compressor A1, the cumulative operating time of compressor 1B, and the cumulative operating time of compressor 1C are discretized (step S15).

When a command to continue control to level out the cumulative operating times of compressors 1A, 1B, and 1C is input via user interface 7, the number-of-units control device 6 continues control to level out the cumulative operating times of compressors 1A, 1B, and 1C (step S19).

Next, a specific example of the operation of this embodiment will be described with reference to FIG.

Figure 4 shows a specific example of the change in the cumulative operating time of each compressor in this embodiment. The numbers in parentheses in Figure 4 indicate the virtual cumulative operating time of each compressor. In this specific example, the specified period is one year, the system operating time per year is 3000 hours, and the system load factor L is 0.67. The specified maintenance time Tmc is 10000 hours, and the target difference ΔT set in the user interface 7 is 2000 hours.

The number-of-compressors control device 6 controls the selection of compressors to be operated so that the cumulative operating time of each of compressors 1A, 1B, and 1C is equalized over the course of one year. As a result, after one year has passed, the cumulative operating time of each of compressors 1A, 1B, and 1C will be 2000 hours.

When one year has passed, the number control device 6 uses the above formulas (1) and (2) to calculate the upper limit value of the target difference ΔTmax = 2667 hours. Then, since the target difference ΔT = 2000 hours set in the user interface 7 is less than the upper limit value ΔTmax, the control proceeds to select the compressor to be operated using this target difference ΔT so that the cumulative operating time of each of compressors 1A, 1B, and 1C is discretized.

To explain in more detail, if the priority order is compressors 1A, 1B, and 1C, the number control device 6 leaves the cumulative operating time of compressor 1A unchanged as the virtual cumulative operating time of compressor 1A, adds the target difference ΔT to the cumulative operating time of compressor 1B to determine the virtual cumulative operating time of compressor 1B, and adds the target difference ΔT x 2 to the cumulative operating time of compressor 1C to determine the virtual cumulative operating time of compressor 1C. As a result, the virtual cumulative operating time of compressor 1A becomes 2000 hours, the virtual cumulative operating time of compressor 1B becomes 4000 hours, and the virtual cumulative operating time of compressor 1C becomes 6000 hours.

The unit count control device 6 controls the selection of compressors so that the virtual cumulative operating time of each of the compressors 1A, 1B, and 1C is averaged, in other words, compressors with shorter virtual cumulative operating times are given priority. As a result, if the annual operating time and load factor of the system do not change, the virtual cumulative operating time of each compressor will change as follows:

After one year and six months have passed, the virtual cumulative operating time of compressor 1A will be 3,500 hours, the virtual cumulative operating time of compressor 1B will be 5,500 hours, and the virtual cumulative operating time of compressor 1C will be 6,000 hours. In reality, the cumulative operating time of compressor 1A will be 3,500 hours, the cumulative operating time of compressor 1B will be 3,500 hours, and the cumulative operating time of compressor 1C will be 2,000 hours.

After two years have passed, the virtual cumulative operating time of compressor 1A will be 5,000 hours, the virtual cumulative operating time of compressor 1B will be 6,500 hours, and the virtual cumulative operating time of compressor 1C will be 6,500 hours. In reality, the cumulative operating time of compressor 1A will be 5,000 hours, the cumulative operating time of compressor 1B will be 4,500 hours, and the cumulative operating time of compressor 1C will be 2,500 hours.

After three years have passed, the virtual cumulative operating time of compressor 1A will be 8,000 hours, the virtual cumulative operating time of compressor 1B will be 8,000 hours, and the virtual cumulative operating time of compressor 1C will be 8,000 hours. In reality, the cumulative operating time of compressor 1A will be 8,000 hours, the cumulative operating time of compressor 1C will be 6,000 hours, and the cumulative operating time of compressor 1C will be 4,000 hours.

After four years have passed, the virtual cumulative operating time of compressor 1A will be 10,000 hours, the virtual cumulative operating time of compressor 1B will be 10,000 hours, and the virtual cumulative operating time of compressor 1C will be 10,000 hours. In reality, the cumulative operating time of compressor 1A will be 10,000 hours, the cumulative operating time of compressor 1B will be 8,000 hours, and the cumulative operating time of compressor 1C will be 6,000 hours. Therefore, only the cumulative operating time of compressor 1A has reached the specified maintenance time, and maintenance is performed only on compressor 1A.

After five years have passed, only the cumulative operating time of compressor 1B will reach the designated maintenance time, and maintenance will be performed only on compressor 1B. After six years have passed, only the cumulative operating time of compressor 1C will reach the designated maintenance time, and maintenance will be performed only on compressor 1C.

As described above, in this embodiment, the cumulative operating time of each of compressors 1A, 1B, and 1C is discretized, making it possible to avoid concentration of maintenance timing and maintenance costs. Furthermore, when a specified period of time has passed, it is possible to estimate whether the set target difference in cumulative operating time is achievable based on the operating performance of the system during the specified period. This can therefore assist the user in making maintenance plans.

In the above embodiment, the number-of-units control device 6 has been described as adding the target difference to the cumulative operating time of each compressor at once to calculate the virtual cumulative operating time, but this is not limited to the above. In other words, the virtual cumulative operating time may be calculated by adding the target difference to the cumulative operating time of each compressor in two separate additions, for example. This type of modified example will be described with reference to FIG. 5.

Figure 5 shows a specific example of the change in the cumulative operating time of each compressor in this modified example. The numbers in parentheses in Figure 5 indicate the virtual cumulative operating time of each compressor. In this specific example, the specified period is one year, the system operating time per year is 3000 hours, and the system load factor L is 0.67. The specified maintenance time Tmc is 10000 hours, and the target difference ΔT set in the user interface 7 is 2000 hours.

When one year has passed, the number-of-units control device 6 leaves the cumulative operating time of compressor 1A unchanged as the virtual cumulative operating time of compressor 1A, adds the target difference ΔT/2 to the cumulative operating time of compressor 1B as the virtual cumulative operating time of compressor 1B, and adds the target difference ΔT to the cumulative operating time of compressor 1C as the virtual cumulative operating time of compressor 1C. As a result, the virtual cumulative operating time of compressor 1A becomes 2000 hours, the virtual cumulative operating time of compressor 1B becomes 3000 hours, and the virtual cumulative operating time of compressor 1C becomes 4000 hours.

The unit count control device 6 controls the selection of compressors so that the virtual cumulative operating time of each of the compressors 1A, 1B, and 1C is averaged, in other words, compressors with shorter virtual cumulative operating times are given priority. As a result, if the annual operating time and load factor of the system do not change, the virtual cumulative operating time of each compressor will change as follows:

After one year and four months have passed, the virtual cumulative operating time of compressor 1A will be 3000 hours, the virtual cumulative operating time of compressor 1B will be 4000 hours, and the virtual cumulative operating time of compressor 1C will be 4000 hours. In reality, the cumulative operating time of compressor 1A will be 3000 hours, the cumulative operating time of compressor 1B will be 3000 hours, and the cumulative operating time of compressor 1C will be 2000 hours.

After two years have passed, the virtual cumulative operating time of compressor 1A will be 5,000 hours, the virtual cumulative operating time of compressor 1B will be 5,000 hours, and the virtual cumulative operating time of compressor 1C will be 5,000 hours. In reality, the cumulative operating time of compressor 1A will be 5,000 hours, the cumulative operating time of compressor 1B will be 4,000 hours, and the cumulative operating time of compressor 1C will be 3,000 hours.

When two years have passed, the unit count control device 6 leaves the virtual cumulative operating time of compressor 1A unchanged, further adds the target difference ΔT/2 to the virtual cumulative operating time of compressor 1B, and further adds the target difference ΔT to the virtual cumulative operating time of compressor 1C. As a result, the virtual cumulative operating time of compressor 1A becomes 5,000 hours, the virtual cumulative operating time of compressor 1B becomes 6,000 hours, and the virtual cumulative operating time of compressor 1C becomes 7,000 hours.

After two years and four months have passed, the virtual cumulative operating time of compressor 1A is 6,000 hours, the virtual cumulative operating time of compressor 1B is 7,000 hours, and the virtual cumulative operating time of compressor 1C is 7,000 hours. In reality, the cumulative operating time of compressor 1A is 6,000 hours, the cumulative operating time of compressor 1B is 5,000 hours, and the cumulative operating time of compressor 1C is 3,000 hours.

After three years have passed, the virtual cumulative operating time of compressor 1A will be 8,000 hours, the virtual cumulative operating time of compressor 1B will be 8,000 hours, and the virtual cumulative operating time of compressor 1C will be 8,000 hours. In reality, the cumulative operating time of compressor 1A will be 8,000 hours, the cumulative operating time of compressor 1B will be 6,000 hours, and the cumulative operating time of compressor 1C will be 4,000 hours.

After four years have passed, the virtual cumulative operating time of compressor 1A will be 10,000 hours, the virtual cumulative operating time of compressor 1B will be 10,000 hours, and the virtual cumulative operating time of compressor 1C will be 10,000 hours. In reality, the cumulative operating time of compressor 1A will be 10,000 hours, the cumulative operating time of compressor 1B will be 8,000 hours, and the cumulative operating time of compressor 1C will be 6,000 hours. Therefore, only the cumulative operating time of compressor 1A has reached the specified maintenance time, and maintenance is performed only on compressor 1A.

After five years have passed, only the cumulative operating time of compressor 1B will reach the designated maintenance time, and maintenance will be performed only on compressor 1B. After six years have passed, only the cumulative operating time of compressor 1C will reach the designated maintenance time, and maintenance will be performed only on compressor 1C.

In this modified example, the same effect as in the above embodiment can be obtained. Furthermore, in this modified example, in the initial stage when the cumulative operating time of the compressors is shifted from being leveled to being discretized, the deviation in the cumulative operating time between compressors 1B and 1C, i.e., the deviation in the operating load, can be reduced compared to the above embodiment.

In the above modified example, the virtual cumulative operating time is calculated by dividing the target difference into two parts and adding it to the cumulative operating time of each compressor. However, this is not limited to this, and the target difference may be divided into three or more parts and added. The number of additions may be set based on a set time interval or based on a divided value of the set target difference.

In the above, the gas compression system has been described using an example in which it has three compressors, but this is not limited thereto, and it may have two or four or more compressors.

1A, 1B, 1C... Compressor, 6... Number of units control device, 7... User interface

Claims (3)

A plurality of compressors;
a number control device that controls the number of operating compressors and acquires the operation time of each of the plurality of compressors;
a user interface for setting a target difference when discretizing the cumulative operation time of each of the plurality of compressors,
The number control device is
performing control to select a compressor to be operated so that the cumulative operation time of each of the plurality of compressors is equalized within a predetermined period of time;
and then, when a cumulative operation time of one of the plurality of compressors reaches a predetermined maintenance time, control is performed to select a compressor to be operated such that the cumulative operation times of the plurality of compressors are shifted by the target difference,
The number control device is
When the predetermined period has elapsed, an upper limit value of the target difference is calculated based on an operation time of each of the plurality of compressors and an operation time of the number control device during the predetermined period;
determining whether the target difference set through the user interface is equal to or smaller than the upper limit;
A gas compression system comprising: a user interface that notifies a user of the target difference set in the user interface when the target difference exceeds the upper limit value. 2. The gas compression system of claim 1,
The number control device is
When the target difference set via the user interface exceeds the upper limit value, a screen is displayed on the user interface for confirming whether or not the target difference should be corrected to the upper limit value;
A gas compression system comprising: a controller for inputting, via the user interface, a command for correcting the target difference to the upper limit value; and a controller for inputting, via the user interface, a command for correcting the target difference to the upper limit value. 3. The gas compression system according to claim 1 or 2,
The number control device is
displaying, on the user interface, a screen for confirming whether or not to continue control for leveling out the accumulated operation times of the plurality of compressors when the target difference set via the user interface exceeds the upper limit value;
a control unit that continues to level out the cumulative operating times of the plurality of compressors when a command to continue the control is input via the user interface to continue the control to level out the cumulative operating times of the plurality of compressors.

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