JP6294779B2 - Air volume control system and air volume control method - Google Patents

Description

  The present invention relates to an air volume control system and an air volume control method that perform an operation combining air volume balance control and room pressure correction control.

  In chemical experiments, biochemical substances that are harmful to the human body are often generated in the course of experimental work. One device that prevents the diffusion of these biochemical substances into the room and prevents contamination of the human body is a fume hood. In general, the fume hood is provided with an enclosure (enclosure) with a sash that can be opened and closed vertically or horizontally, and a laboratory worker can access the enclosure from the sash. To prevent workers working in the fume hood from being exposed to harmful biochemicals, the enclosure is connected to a local exhaust duct that removes the biochemicals.

  The air flow control system adjusts the room pressure so that biochemical substances do not leak out of the room or impurities from outside flow into the room when conducting experiments with biochemical substances in the fume hood. This is a system that keeps constant (see Patent Document 1). In this air volume control system, the positive and negative pressure in the room is controlled by controlling the air supply valve and the exhaust valve so that the difference between the air volume of the supply air blown into the room and the air volume of the exhaust air drawn out from the room becomes a predetermined air volume (offset air volume). Is maintained, that is, air volume balance control is performed.

  In addition, in order to perform stable chamber pressure control, a chamber pressure correction control valve is provided, and the chamber pressure correction control valve controls the air volume of the chamber pressure correction control valve so that the differential pressure between the reference pressure and the chamber pressure is constant. Control is known (see Patent Document 2 and Patent Document 3).

JP 2012-237527 A Japanese Patent No. 5118425 Japanese Patent No. 5296903

  When the air pressure balance control is combined with the air flow balance control to strictly control the room pressure, the air pressure of the air supply / exhaust valve for air flow balance control changes slightly. Each time the air flow changes, the air flow of the room pressure correction control valve also changes. Since the chamber pressure correction control valve changes the air volume in accordance with the fluctuation of the chamber pressure due to disturbance, the number of valve operations is larger than that of other supply / exhaust valves. Further, when the air pressure balance control is combined with the room pressure correction control, the number of operations of the room pressure correction control valve increases due to the above reason. For this reason, the lifetime of the chamber pressure correction control valve is short, and it is necessary to replace it regularly.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to reduce the number of operation times of a chamber pressure correction control valve in an air volume control system that combines air volume balance control with room pressure correction control.

An air volume control system according to the present invention includes an air supply valve that adjusts an air volume of supply air that is blown out to a target facility, an exhaust valve that adjusts an air volume of exhaust air that is sucked out from the target facility, and a supply valve that controls the room pressure of the target facility. A difference between a chamber pressure correction control valve for adjusting one of the air volume and the exhaust air volume, and a supply air volume adjusted by the air supply valve and an exhaust air volume adjusted by the exhaust valve is a predetermined air volume setting value. Air volume balance control means for determining the supply air volume of the intake valve and the exhaust air volume of the exhaust valve to control the supply valve and the exhaust valve, and a reference chamber pressure. A chamber pressure correction control means for controlling the chamber pressure correction control valve so that the inter-room differential pressure between the reference room and the target facility matches a predetermined differential pressure setting value; and a preset schedule or an external An air volume changing means for instructing an air volume change to the air volume balance control means in accordance with the indication, and when receiving an air volume changing instruction from the air volume changing means, the chamber pressure is changed by changing the supply air volume and the exhaust air volume. Air volume correction means for changing at least one of the supply air volume and the exhaust air volume determined by the air volume balance control means in accordance with an instruction from the air volume change means so that the air volume of the correction control valve does not change. It is characterized by this.
In the configuration example of the air volume control system of the present invention, when the air volume correction unit corrects the offset air volume, which is the difference between the supply air volume and the exhaust air volume, in the direction of widening the air volume balance control unit, When the supply air volume determined according to the instruction from the changing means is reduced and the offset air volume is corrected in a narrowing direction, the exhaust air volume determined by the air volume balance control means according to the instruction from the air volume changing means is reduced. It is characterized by this.

  Further, according to the air volume control method of the present invention, the difference between the supply air volume adjusted by the supply air valve installed in the target facility and the exhaust air volume adjusted by the exhaust valve installed in the target facility is a predetermined air volume setting. An air volume balance control step for determining an air supply amount of the air supply valve and an exhaust air amount of the exhaust valve so as to match the values, and controlling the air supply valve and the exhaust valve; and a chamber of the target facility For controlling the pressure, a room pressure correction control valve that adjusts one of the supply air volume and the exhaust air volume is controlled, and the inter-room differential pressure between the reference chamber set to the reference chamber pressure and the target facility is predetermined. A chamber pressure correction control step that matches the set pressure difference value, an air volume change step that issues an air volume change instruction according to a preset schedule or an external instruction, and when the air volume change instruction is received, At least one of the supply air volume and the exhaust air volume determined according to the air volume change instruction in the air volume balance control step so that the air volume of the room pressure correction control valve does not change due to the change of the air volume and the exhaust air volume And an air volume correction step for changing.

  According to the present invention, the room pressure correction control is performed by changing at least one of the supply air volume and the exhaust air volume determined by the air volume balance control means when the air volume change instruction is received from the air volume changing means by the air volume correction means. Variations in the air volume of the valve can be suppressed, and the number of operations of the room pressure correction control valve can be reduced. As a result, in the present invention, the life of the room pressure correction control valve can be extended, and maintenance work such as replacement and inspection of the room pressure correction control valve can be reduced.

  Further, in the present invention, the air volume correction means corrects the offset air volume, which is the difference between the supply air volume and the exhaust air volume, in the direction of widening the supply volume determined by the air volume balance control means according to the instruction from the air volume changing means. When the air volume is reduced and the offset air volume is corrected in the narrowing direction, the air volume balance control means reduces the exhaust air volume determined according to the instruction from the air volume changing means. Thereby, in this invention, it can contribute to energy saving.

It is a figure which shows the structure of the air volume control system which concerns on embodiment of this invention. It is a block diagram which shows the structure of the controller of the air volume control system which concerns on embodiment of this invention. It is a flowchart explaining the air volume balance control operation | movement and room pressure correction | amendment control operation of the air volume control system which concerns on embodiment of this invention. It is a flowchart explaining the air volume change control operation | movement of the air volume control system which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of an air volume control system according to an embodiment of the present invention. The air volume control system of the present embodiment includes an air supply duct 101 that supplies air to the room 100, an exhaust duct 102 that exhausts air in the room 100, and an air supply valve MAV that adjusts the air volume of the air supply duct 101. An exhaust valve GEX for adjusting the air volume of the exhaust duct 102, a room pressure correction control valve PCV provided in the air supply duct 101, a controller 103 for controlling the air supply valve MAV and the room pressure correction control valve PCV, and an exhaust valve A controller 104 that controls GEX, a communication line 105 that connects the controllers 103 and 104 to each other, and a differential pressure sensor 106 that measures a pressure difference between a predetermined reference chamber 110 and the room 100 are configured.

  FIG. 2 is a block diagram showing a configuration of the controller 103 of the present embodiment. The controller 103 controls the supply air volume of the supply valve MAV and the exhaust gas so that the difference between the supply air volume adjusted by the supply valve MAV and the exhaust air volume adjusted by the exhaust valve GEX matches a predetermined air volume setting value. The air flow balance control unit 1 that determines the exhaust air volume of the valve GEX and controls the air supply valve MAV and the exhaust valve GEX, and the differential pressure between the reference chamber 110 and the room 100 set to the reference chamber pressure is The chamber pressure correction control unit 2 that controls the chamber pressure correction control valve PCV so as to coincide with a predetermined differential pressure setting value, and the air volume change control unit 1 is configured to change the air volume according to a preset schedule or an external instruction. When an air volume change unit 3 that gives an instruction and an instruction to change the air volume are received from the air volume change unit 3, the air volume of the room pressure correction control valve PCV is changed by changing the supply air volume and the exhaust air volume. Is so as not to cause an air volume balance control unit 1 and a flow rate correcting section 4 to change at least one of supply air volume and exhaust air amount determined in accordance with an instruction from the flow rate changing section 3.

  Next, the air volume balance control operation and the room pressure correction control operation of the air volume control system of the present embodiment will be described. FIG. 3 is a flowchart for explaining the air volume balance control operation and the room pressure correction control operation. In the present embodiment, a case where the room pressure correction control valve PCV is arranged in the air supply duct 101 will be described. Let Vmav be the amount of air supplied through the air supply valve MAV, Vpcv be the amount of air supplied through the chamber pressure correction control valve PCV, and Vgex be the amount of air exhausted through the exhaust duct 102.

The air volume balance control unit 1 determines the supply air volume Vmav and the exhaust air volume Vgex so that the difference between the supply air volume Vmav and the exhaust air volume Vgex matches a predetermined air volume setting value α (step S1 in FIG. 3).
Vmav = Vgex + α (1)

  The airflow setting value α in the equation (1) determines the airflow leaking from the target facility (the room 100 in FIG. 1) and the offset airflow for determining whether the room 100 is set to a positive pressure or a negative pressure. It is. However, the air volume balance control unit 1 determines the air supply air volume Vmav so that at least the minimum air volume is always blown out so as to satisfy the minimum ventilation air volume of the room 100.

  The air volume balance control unit 1 controls the opening degree of the air supply valve MAV so that the air volume of the air supply adjusted by the air supply valve MAV becomes the air volume Vmav determined in step S1 (step S2 in FIG. 3). The air volume balance control unit 1 controls the opening degree of the exhaust valve GEX via the controller 104 so that the exhaust air volume adjusted by the exhaust valve GEX becomes the air volume Vgex determined in step S1 (step S3 in FIG. 3). .

On the other hand, the differential pressure sensor 106 measures the inter-room differential pressure between the reference chamber 110 and the room 100 set to the reference chamber pressure. The room pressure correction control unit 2 determines the supply air volume Vpcv so that the inter-room differential pressure measured by the differential pressure sensor 106 matches a predetermined differential pressure setting value (step S4 in FIG. 3). Then, the chamber pressure correction control unit 2 controls the opening of the chamber pressure correction control valve PCV so that the air volume of the supply air adjusted by the chamber pressure correction control valve PCV becomes the air volume Vpcv determined in step S4 (FIG. 3 step S5).
In this way, for example, until the air volume control is ended by an instruction from the user (YES in step S6 in FIG. 3), the processes of steps S1 to S5 are repeatedly performed for each control cycle.

  Next, the air volume change control operation will be described. As an example in which the air supply volume Vmav and the exhaust air volume Vgex are changed, the air supply is maintained while maintaining a constant pressure difference between the inside and outside in order to save energy in the time zone when there are no people such as night time or holidays when work is not performed. There is an air volume change control operation that lowers the air volume Vmav and the exhaust air volume Vgex. This air volume change is performed every day on weekdays. In the example of switching from day to night, both the supply air volume Vmav and the exhaust air volume Vgex are gradually reduced, and in the example of switching from night to day, both the supply air volume Vmav and the exhaust air volume Vgex are gradually increased. Further, there is a case where an instruction to change the air volume is received from the outside along with the temperature control of the room 100.

  FIG. 4 is a flowchart for explaining the air volume change control operation. The air volume changing unit 3 receives an instruction to change the air volume when changing the air volume according to a preset schedule (for example, when switching from noon to night or when switching from night to noon), or from outside. If this is the case (YES in step S10 in FIG. 4), the air volume balance control unit 1 is instructed to change the supply air volume Vmav (step S11 in FIG. 4).

  Receiving the instruction from the air volume changing unit 3, the air volume balance control unit 1 changes the air supply air volume Vmav (step S12 in FIG. 4). At this time, the air volume balance control unit 1 changes the exhaust air volume Vgex in accordance with the change in the supply air volume Vmav, but determines the exhaust air volume Vgex so that the formula (1) is satisfied even after the air volume is changed.

  On the other hand, when the air volume change instruction is issued from the air volume changing section 3, the air volume correcting section 4 is configured so that the air volume of the room pressure correction control valve PCV is not changed when the supply air volume Vmav and the exhaust air volume Vgex are changed. The balance control unit 1 changes the exhaust air volume Vgex determined in step S12 (step S13). The air volume correction unit 4 includes an air volume table (not shown) that stores in advance the relationship between the supply air volume Vmav and the exhaust air volume Vgex and the air volume Vpcv of the room pressure correction control valve PCV.

  The air volume correction unit 4 reads the air volume Vpcv of the room pressure correction control valve PCV corresponding to the supply air volume Vmav before the change and the exhaust air volume Vgex before the change from the air volume table, and the air volume balance control unit 1 determines in step S12. The changed supply air volume Vmav and the air volume balance control unit 1 read out the air volume Vpcv ′ of the chamber pressure correction control valve PCV corresponding to the changed exhaust air volume Vgex determined in step S12 from the air volume table. Then, the air volume correction unit 4 calculates the air volume fluctuation amount ΔVpcv = Vpcv′−Vpcv of the chamber pressure correction control valve PCV by changing the supply air volume Vmav and the exhaust air volume Vgex, and corrects the exhaust air volume Vgex from the fluctuation amount ΔVpcv. By calculating the amount ΔVgex = −ΔVpcv, the exhaust air amount Vgex determined by the air amount balance control unit 1 in step S12 may be changed to Vgex ′ = Vgex + ΔVgex. The air volume Vpcv registered in the air volume table may be investigated by a prior experiment.

  Note that the air volume correction unit 4 has the air supply air volume Vmav before the change and the exhaust air volume Vgex before the change and the air supply air volume Vmav after the change determined by the air volume balance control unit 1 and the air flow balance control unit 1 after the change determined. A correction value table (not shown) for storing in advance the relationship between the exhaust air volume Vgex and the correction value Vgex ′ of the exhaust air volume Vgex may be provided. The air volume correction unit 4 determines the supply air volume Vmav before the change, the exhaust air volume Vgex before the change, the air supply balance control unit 1 after the change determined in step S12, and the air supply balance Vmav after the change determined in step S12. The correction value Vgex ′ of the exhaust air volume Vgex corresponding to the changed exhaust air volume Vgex may be read from the correction value table, and the exhaust air volume control unit 1 may change the exhaust air volume Vgex determined in step S12 to Vgex ′. The correction value Vgex ′ registered in the correction value table is equal to the air volume of the chamber pressure correction control valve PCV when the supply air volume Vmav and the exhaust air volume Vgex are changed to the changed supply air volume Vmav and exhaust air volume Vgex ′. It may be determined by prior experiments so that no change occurs.

  In addition, the air volume correction unit 4 is the air supply air volume Vmav before the change and the exhaust air volume Vgex before the change and the air supply air volume Vmav after the change determined by the air volume balance control unit 1 and the air flow balance control unit 1 after the change is determined. A correction amount table (not shown) that stores in advance the relationship between the exhaust air volume Vgex and the correction amount ΔVgex = Vgex′−Vgex of the exhaust air volume Vgex may be provided. The air volume correction unit 4 determines the supply air volume Vmav before the change, the exhaust air volume Vgex before the change, the air supply balance control unit 1 after the change determined in step S12, and the air supply balance Vmav after the change determined in step S12. The correction amount ΔVgex of the exhaust air volume Vgex corresponding to the changed exhaust air volume Vgex is read from the correction amount table, and the exhaust air volume Vgex determined by the air volume balance control unit 1 in step S12 is changed to Vgex ′ = Vgex + ΔVgex. . The correction amount ΔVgex registered in the correction amount table is changed to the air volume of the chamber pressure correction control valve PCV when the supply air volume Vmav and the exhaust air volume Vgex are changed to the changed supply air volume Vmav and the exhaust air volume Vgex ′. It may be determined by a prior experiment so as not to occur.

  The air volume balance control unit 1 controls the opening degree of the air supply valve MAV so that the air volume of the air supply adjusted by the air supply valve MAV becomes the air volume Vmav determined in step S12 (step S14 in FIG. 4). Further, the air volume balance control unit 1 determines that the exhaust air volume adjusted by the exhaust valve GEX is equal to the air volume Vgex determined in step S12, or when the air volume correction unit 4 changes the air volume determined in step S13. The opening degree of the exhaust valve GEX is controlled via the controller 104 so as to be Vgex ′ (step S15 in FIG. 4).

  As described above, the air volume balance control unit 1 gradually changes the supply air volume Vmav and the exhaust air volume Vgex, so that the supply air volume Vmav reaches the air volume value preset in the schedule or the air volume value specified from the outside ( In step S16 of FIG. 4, YES, and the processing of steps S12 to S15 is repeated every control cycle. The air volume balance control after the air volume change is as described above.

  In the air volume balance control after the air volume change, if the exhaust air volume Vgex is changed by the air volume correction unit 4 when the air volume is changed, the formula (1) may be temporarily not satisfied, but the air volume balance is not satisfied. The control unit 1 maintains the supply air volume Vmav and the exhaust air volume Vgex finally set by the air volume change control operation of FIG. 4 until the next air volume change occurs.

  As described above, in the present embodiment, the room pressure correction is performed by changing the exhaust air volume Vgex determined by the air volume balance control unit 1 when receiving the air volume change instruction from the air volume changing unit 3. Variations in the air volume of the control valve PCV can be suppressed, and the number of operations of the room pressure correction control valve PCV can be reduced. As a result, in the present embodiment, the life of the room pressure correction control valve PCV can be extended, and maintenance work such as replacement and inspection of the room pressure correction control valve PCV can be reduced.

For example, in a conventional system that combines air volume balance control with room pressure correction control, the room pressure correction control valve PCV when the air volume is balanced with the supply air volume Vmav = 1000 m ³ / h and the exhaust air volume Vgex = 1200 m ³ / h. Suppose the air volume of Vpcv = 100 m ³ / h. Further, it is assumed that the air volume of the chamber pressure correction control valve PCV when the air volume balance is achieved with the supply air volume Vmav = 2000 m ³ / h and the exhaust air volume Vgex = 2200 m ³ / h is Vpcv = 200 m ³ / h. In this case, if the supply air volume Vmav and the exhaust air volume Vgex are increased as a result of the air volume balance control, the air volume Vpcv of the room pressure correction control valve PCV is increased from 100 m ³ / h to 200 m ³ / h.

On the other hand, in this embodiment, by calculating a correction amount ΔVgex = -100m ³ / h of exhaust air volume Vgex, since changing the exhaust airflow volume Vgex to 2100 m ³ / h, air volume of the room pressure correction control valve PCV is Vpcv = 100 m ³ / h, and it is not necessary to change the air volume Vpcv of the room pressure correction control valve PCV.

  In this embodiment, the room pressure correction control valve PCV is arranged in the air supply duct 101, but may be arranged in the exhaust duct 102. In this case, Vpcv is the exhaust air volume adjusted by the room pressure correction control valve PCV.

  In the present embodiment, when the air volume change instruction is issued from the air volume changing section 3, the air volume correcting section 4 changes the exhaust air volume Vgex. However, the air volume correcting section 4 changes the supply air volume Vmav. You may do it. When changing the supply air volume Vmav, the air volume correction unit 4 calculates the amount of fluctuation ΔVpcv = Vpcv′−Vpcv of the chamber pressure correction control valve PCV due to the change of the supply air volume Vmav and the exhaust air volume Vgex, and this fluctuation amount. By calculating the correction amount ΔVmav = −ΔVpcv of the supply air amount Vmav from ΔVpcv, the supply air amount Vmav determined by the air amount balance control unit 1 in step S12 may be changed to Vmav ′ = Vmav + ΔVmav.

  When a correction value table (not shown) is used, the air volume correction unit 4 changes the supply air volume Vmav before change, the exhaust air volume Vgex before change, and the supply after change determined by the air volume balance control unit 1 in step S12. The correction value Vmav ′ of the supply air volume Vmav corresponding to the air volume Vmav and the changed exhaust air volume Vgex determined in step S12 by the air volume balance controller 1 is read from the correction value table, and the air volume balance controller 1 in step S12. The determined supply air volume Vmav may be changed to Vmav ′. When a correction amount table (not shown) is used, the air volume correction unit 4 changes the supply air volume Vmav before change, the exhaust air volume Vgex before change, and the supply after change determined by the air volume balance control unit 1 in step S12. The correction amount ΔVmav of the supply air volume Vmav corresponding to the air volume Vmav and the changed exhaust air volume Vgex determined by the air volume balance control unit 1 in step S12 is read from the correction amount table, and the air volume balance control unit 1 determines in step S12. The supplied air volume Vmav may be changed to Vmav ′ = Vmav + ΔVmav.

  Further, when an air volume change instruction is issued from the air volume changing unit 3, the air volume correcting unit 4 may change both the exhaust air volume Vgex and the supply air volume Vmav. When an air volume table (not shown) is used, the air volume correcting unit 4 calculates a correction amount calculated from the air volume fluctuation amount ΔVpcv of the room pressure correction control valve PCV, for example, an exhaust air volume Vgex correction amount ΔVgex and an air supply air volume Vmav. What is necessary is just to divide equally into correction amount (DELTA) Vmav.

  When a correction value table (not shown) is used, the air volume correction unit 4 changes the supply air volume Vmav before change, the exhaust air volume Vgex before change, and the supply after change determined by the air volume balance control unit 1 in step S12. The correction value Vgex of the exhaust air volume Vgex and the correction value Vmav ′ of the air supply air volume Vmav corresponding to the air volume Vmav and the changed exhaust air volume Vgex determined by the air volume balance control unit 1 in step S12 are read from the correction value table. The air volume balance control unit 1 may change the exhaust air volume Vgex determined in step S12 to Vgex ′, and the air volume balance control unit 1 may change the supply air volume Vmav determined in step S12 to Vmav ′.

  When a correction amount table (not shown) is used, the air volume correction unit 4 changes the supply air volume Vmav before change, the exhaust air volume Vgex before change, and the supply after change determined by the air volume balance control unit 1 in step S12. The correction amount ΔVgex of the exhaust air amount Vgex and the correction amount ΔVmav of the supply air amount Vmav corresponding to the air flow amount Vmav and the changed exhaust air amount Vgex determined in step S12 by the air amount balance control unit 1 are read from the correction amount table. The exhaust air volume Vgex determined by the control unit 1 in step S12 may be changed to Vgex ′ = Vgex + ΔVgex, and the supply air volume Vmav determined by the air volume balance control unit 1 in step S12 may be changed to Vmav ′ = Vmav + ΔVmav.

  The controllers 103 and 104 described in the present embodiment can be realized by, for example, a computer having a CPU (Central Processing Unit), a storage device, and an interface, and a program that controls these hardware resources. The CPUs of the controllers 103 and 104 execute the processing described in the present embodiment in accordance with programs stored in the storage devices of the controllers.

  In the present embodiment, the air volume correction unit 4 reduces the supply air volume Vmav determined by the air volume balance control unit 1 in accordance with an instruction from the air volume changing unit 3 when correcting the offset air volume α in the direction of widening. When correcting the offset air volume α in the direction of narrowing, the exhaust air volume Vgex determined by the air volume balance control unit 1 according to the instruction from the air volume changing unit 3 may be reduced. Thereby, it can contribute to energy saving.

  The present invention can be applied to a system that combines air pressure balance control with room pressure correction control.

  DESCRIPTION OF SYMBOLS 1 ... Air volume balance control part, 2 ... Room pressure correction control part, 3 ... Air volume change part, 4 ... Air volume correction part, 100 ... Room, 101 ... Air supply duct, 102 ... Exhaust duct, 103,104 ... Controller, 105 ... Communication line 106 ... Differential pressure sensor 110 ... Reference chamber MAV ... Air supply valve GEX ... Exhaust valve PCV ... Room pressure correction control valve

Claims (4)

An air supply valve that adjusts the amount of air supplied to the target facility;
An exhaust valve for adjusting the amount of exhaust air sucked out from the target facility;
A room pressure correction control valve that adjusts either the supply air volume or the exhaust air volume for controlling the room pressure of the target facility;
The supply air volume of the supply valve and the exhaust valve of the exhaust valve are adjusted so that the difference between the supply air volume adjusted by the supply valve and the exhaust air volume adjusted by the exhaust valve matches a predetermined air volume setting value. An air volume balance control means for determining an air volume and controlling the air supply valve and the exhaust valve;
A chamber pressure correction control means for controlling the chamber pressure correction control valve so that a differential pressure between the reference chamber set to a reference chamber pressure and the target facility matches a predetermined differential pressure setting value;
An air volume changing means for instructing an air volume change to the air volume balance control means according to a preset schedule or an external instruction;
When the air volume change instruction is received from the air volume changing means, the air volume balance control means is configured to prevent the air volume balance control means from changing the air volume of the chamber pressure correction control valve due to the change in the supply air volume and the exhaust air volume. An air volume control system comprising: an air volume correcting means for changing at least one of an air supply air volume and an exhaust air volume determined according to an instruction from the changing means. The air volume control system according to claim 1,
When the air volume correction means corrects the offset air volume, which is the difference between the supply air volume and the exhaust air volume, in the direction of widening the offset air volume, the air volume balance control means determines the supply air volume determined according to the instruction from the air volume changing means. The air volume control system according to claim 1, wherein the air volume balance control means reduces the exhaust air volume determined in accordance with an instruction from the air volume changing means when the offset air volume is corrected in a direction to reduce the offset air volume. The air supply so that a difference between an air supply amount adjusted by an air supply valve installed in the target facility and an exhaust air amount adjusted by an exhaust valve installed in the target facility matches a predetermined airflow setting value. An air volume balance control step for determining a supply air volume of the valve and an exhaust air volume of the exhaust valve, and controlling the supply valve and the exhaust valve;
The room between the reference room set to the reference room pressure and the target facility is controlled by controlling a room pressure correction control valve that adjusts either the supply air volume or the exhaust air volume for controlling the room pressure of the target facility. A chamber pressure correction control step for matching the differential pressure to a predetermined differential pressure setting value;
An air volume changing step for issuing an instruction to change the air volume according to a preset schedule or an external instruction;
When the air volume change instruction is received, the air volume change instruction is used in the air volume balance control step so that the air volume of the room pressure correction control valve does not change due to the change in the supply air volume and the exhaust air volume. An air volume control method comprising: an air volume correction step for changing at least one of an air supply air volume and an exhaust air volume determined accordingly. In the air volume control method according to claim 3,
In the air volume correction step, when correcting the offset air volume, which is the difference between the supply air volume and the exhaust air volume, in the direction of widening, the supply air volume determined according to the air volume change instruction in the air volume balance control step is reduced, When correcting in the direction of narrowing the offset air volume, the air volume control method is characterized in that the exhaust air volume determined in accordance with the air volume change instruction in the air volume balance control step is reduced.

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