JP2009019871A - Room pressure control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a room pressure control system capable of maintaining room pressure at a set value in a stop or start process of air supply and in a stop or start process of air discharge. <P>SOLUTION: Exhaust air quantities by an air exhaust fan 23 and an air return fan 26 with constant air quantities from respective zones to which air is supplied by an air conditioner 10 having inverter-controllable rotating frequency, are controlled by VAV valves 2, to maintain the room pressure in each of the zones at a set value. When the air supply quantity to each of the zones is stopped, a VST valve 3 provided on an air supply passage 101 is closed by using time set so that the speed of change in the air passing quantity on the air supply passage 101 is below the speed of change in the air passing quantity by the VAV valve 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a chamber pressure control system that controls a chamber pressure to a desired value by controlling an exhaust amount or an intake amount in accordance with an intake amount or an exhaust amount, and in particular, The present invention relates to a chamber pressure control system capable of controlling a chamber pressure to a desired value in a stop process.

  In facilities such as pharmaceutical factories that require a clean environment, a plurality of rooms filled with clean air are formed. These rooms are generally formed by connecting a plurality of rooms in parallel to the air supply passage and the exhaust passage. In these rooms, the required cleanliness differs depending on the process performed in the room and the use of the room. The cleanliness of the room is realized by keeping the air pressure in the room (hereinafter also referred to as “room pressure”) at a different pressure from the atmospheric pressure, the air pressure in the air supply passage, and the air pressure in the exhaust passage. The difference in cleanliness is realized by controlling different room pressures for each room. Such a chamber pressure is controlled by a subtle difference between the air supply amount and the exhaust amount.

  As a system used for controlling the chamber pressure, for example, there are an adjustment damper and an airtight damper provided in series in each of the air supply path and the exhaust path, and the operation order of these dampers is defined. System (for example, refer to Patent Document 1) and a system that prevents large fluctuations in the room pressure when the door provided in the room is closed without stopping the control of the room pressure by the adjustment damper (for example, And a system that controls the output of the fan so that the opening of the adjustment damper becomes an intermediate opening (see, for example, Patent Document 3) or a plurality of rooms. There is known a system in which one of exhaust adjustment dampers is provided in an exhaust passage downstream of all other exhaust adjustment dampers (see, for example, Patent Document 4).

Japanese Patent No. 3089130 JP 2002-181361 A Japanese Patent Laid-Open No. 11-173649 Japanese Patent Publication No. 8-27044

  In a room where clean air is supplied as described above, in order to sterilize or refurbish the room, it is necessary to temporarily stop air supply to the room. In the case where clean air is supplied to a plurality of rooms as described above, it is desirable that the room pressure for each room be maintained even in the process of stopping or starting the supply of air to some rooms. ing.

  However, in the above-described conventional room pressure control system, the delicate balance between the air supply amount and the exhaust amount may be lost due to the difference in the actual volume of each room and the difference in the opening / closing time of the airtight damper. Therefore, in the conventional room pressure control system, the set value of each room cannot be maintained in the process of stopping or starting the supply air, and the room pressure for each room may not be maintained. For this reason, in the conventional room pressure control system, cross-contamination (cross-contamination) may occur between a plurality of rooms in the process of stopping or starting the supply air.

  The present invention has been made in view of the above matters, and provides a chamber pressure control system capable of maintaining a chamber pressure at a set value in a supply air stop process or a start process or an exhaust stop process or a start process. This is the issue.

  In the steady state operation, the present invention controls the exhaust amount or the air supply amount corresponding to the predetermined air supply amount or the predetermined exhaust amount to keep the room pressure constant, and stops the air supply or exhaust. In the process of starting, except that the air supply amount or the exhaust amount is changed at a specific speed, the exhaust amount or the air supply amount is controlled in accordance with the air supply amount or the predetermined exhaust amount as in the steady state operation. This system keeps the room pressure constant.

  That is, the present invention has a chamber pressure detecting means for detecting the atmospheric pressure of a room in which air of a predetermined flow rate is supplied from the air supply passage and the air is discharged to the exhaust passage, and the detection value by the chamber pressure detecting means is maintained at the set value. A first air flow control means for controlling the air flow of the exhaust passage or the air flow of the air supply passage so as to lean, and the process of stopping or starting the air supply to the room, or the process of stopping or starting the exhaust from the room A second air flow rate control means for changing the air flow rate of the air supply passage or the air flow rate of the exhaust passage in the process, and the second air flow rate control means is a process of stopping or starting air supply to the room Or in the process of stopping or starting the exhaust from the room, the first ventilation amount control means receives the detection value from the chamber pressure detection means, controls the ventilation amount of the exhaust passage or the ventilation amount of the supply passage, and again A control of the first air flow rate control means, which is the time until the detection value is received The air flow rate of the air supply passage or the air flow rate of the exhaust passage by the second air flow rate control means that changes during the cycle becomes the air flow rate corresponding to the allowable control deviation of the first air flow rate control means. In addition, there is a room pressure control system which is a means for changing the ventilation amount of the supply passage or the ventilation amount of the exhaust passage.

  According to the above configuration, in the process of stopping or starting the supply of air to the room, or in the process of stopping or starting the exhaust from the room, the fluctuation rate of the supply amount or the exhaust amount is controlled by the exhaust amount or the supply amount. Since the balance between the air supply amount and the exhaust amount for maintaining the detected value at the set value is appropriately maintained below the speed, the supply air stop process or start process, or the exhaust stop process or start process It becomes possible to keep the chamber pressure at the set value. In the present invention, the chamber pressure can be kept at the set value in any of the above-described processes by the installation form of the first ventilation amount control means and the second ventilation amount control means.

  In the present invention, the second ventilation amount control means is a means for opening and closing the supply passage or the exhaust passage at a constant speed, and the first ventilation amount control means freely opens and closes the exhaust passage or the supply passage. The time required for the control from the fully open to the fully closed state of the second air flow rate control means or from the fully closed state to the fully open state is 10 to 10 times the shortest time from the fully open to the fully closed state of the first air flow amount control means. 60 times is preferable in applying the present invention to a system in which a plurality of rooms are connected in parallel to the air supply passage and the exhaust passage, and the supply air stop process or start process, or the exhaust It is preferable for keeping the chamber pressure at the set value in the stop process or the start process.

  In the present invention, the second ventilation amount control means is a means for opening and closing the supply passage or the exhaust passage at a constant speed, and the second ventilation amount control means is fully opened to fully closed or fully closed to fully opened. In order to apply the present invention to a system in which a plurality of rooms are connected in parallel to the air supply passage and the exhaust passage, it is preferable that the time required for the control up to 180 seconds or more is It is preferable to keep the chamber pressure at a set value in the stop process or start process, or in the exhaust stop process or start process.

  In the present invention, the air supplied to the room from the air supply passage is air purified by an air purifying means for removing contaminants in the air. It is preferable in applying the invention.

The present invention is applied to a system having a room, an air supply passage for supplying air of a predetermined flow rate to the room, and an exhaust passage for discharging the room air. In the present invention, the number of the rooms is not particularly limited. When the present invention is applied to a plurality of rooms, the plurality of rooms are usually connected in parallel to the air supply passage and the exhaust passage.

  The room pressure detecting means is not particularly limited as long as it is means for detecting the air pressure in the room. As such a chamber pressure detecting means, a known barometer can be used.

  The first ventilation amount control means controls the amount of air discharged from the room or the amount of air supplied to the room so that the detection value by the room pressure detection means is maintained at a set value. It is means to do. Such a first ventilation amount control means is based on, for example, a means such as a damper or a valve that opens and closes an exhaust passage or an air supply passage in response to an instruction command, and a detected value and a set value by a chamber pressure detecting means. And a feedback control means for determining an air flow amount, determining an operation amount of a means for opening / closing the exhaust passage or the air supply passage, and transmitting an instruction command relating to the operation amount to the means for opening / closing the exhaust passage or the air supply passage. Can do.

  The set value is not particularly limited as long as it can set the atmospheric pressure of the room. For example, the set value may be set by the absolute pressure or gauge pressure of the room, or set by the value of the differential pressure between the inside and outside of the room. May be. The detected value may be a value of a kind that can be appropriately compared with the set value. For example, the detected value may be a value that is directly compared with the set value, or may be a value that is compared with the set value after performing some calculation processing. It may be. The calculation process may be performed by the chamber pressure detection unit, the first ventilation amount control unit, or may be performed by another unit. In the case where the atmospheric pressure in the room is set with the value of the differential pressure, atmospheric pressure detection means for detecting the atmospheric pressure at an appropriate location outside the room is used. In this atmospheric pressure detection means, the chamber pressure detection means can be constituted by the same means.

  The second air flow rate control means controls the air supply amount to the room or the exhaust amount from the room in the process of stopping or starting the supply of air to the room, or in the process of stopping or starting the exhaust from the room. It is a means to change. The second ventilation amount control means is provided in a pair with respect to the first ventilation amount control means with respect to air supply to the room and exhaust from the room. For example, if the first ventilation amount control means is a means for controlling the ventilation amount of the exhaust passage, the second ventilation amount control means is a means for controlling the supply amount of the supply passage, and the first ventilation amount. If the control means is a means for controlling the air flow rate in the supply passage, the second air flow rate control means is a means for controlling the air flow rate in the exhaust passage. The first ventilation amount control means and the second ventilation amount control means only have to be provided in pairs in their functions. The configuration and installation position of these means, the supply passage, the exhaust passage, and the room Various forms can be taken depending on the connection form and the like.

  More specifically, the second ventilation amount control means controls the first ventilation amount control means in the process of stopping or starting the supply of air to the room, or in the process of stopping or starting the exhaust from the room. The air flow rate of the air supply passage or the air flow rate of the exhaust passage by the second air flow rate control means that changes during the cycle becomes the air flow rate corresponding to the allowable control deviation of the first air flow rate control means. Further, it is a means for changing the amount of ventilation in the air supply passage or the amount of exhaust in the exhaust passage. In one control cycle of the first ventilation amount control means, the first ventilation amount control means receives the detection value from the chamber pressure detection means and controls the ventilation amount in the exhaust passage or the supply passage. , The time until the detection value is received again.

  As such second ventilation amount control means, means for changing the ventilation amount of the supply passage or the exhaust passage at a specific speed is used. For example, a damper or the like for opening and closing the supply passage or the exhaust passage at a constant speed. A means such as a valve or a blowing means such as a fan capable of freely adjusting the air flow rate is used.

When the means for opening and closing the air supply passage or the exhaust passage at a constant speed is used as the second ventilation amount control means, the air supply passage is provided when a plurality of rooms are connected in parallel to the air supply passage or the exhaust passage. Alternatively, it is possible to stop or start only the supply or exhaust of a specific room while maintaining the room pressure of the room without stopping the ventilation of the exhaust passage. Further, in the case where the air blowing means is used as the second ventilation amount control means, when a plurality of rooms are connected in parallel to the air supply passage or the exhaust passage, all the air supply or exhaust to all the rooms is performed. It is possible to stop or start all of the rooms while maintaining the room pressure.

  The speed at which the air supply amount or the exhaust amount is changed in the second ventilation amount control means varies depending on the allowable control deviation of the first ventilation amount control means. The allowable control deviation of the first ventilation amount control means is a deviation between the set value and the detected value that allows the first ventilation amount control means to independently maintain the chamber pressure at the set value. The second ventilation rate control means “changes the ventilation rate in the supply passage or the ventilation rate in the exhaust passage so that the ventilation rate corresponds to the allowable control deviation of the first ventilation rate control means”. The detection value that changes according to the change in the air flow rate of the second air flow rate control unit during one control cycle of the first air flow rate control unit is permitted by the first air flow rate control unit. The second ventilation amount control means changes the air supply amount or the exhaust amount so as to be within the range of the control deviation.

  The permissible control deviation of the first air flow control means varies depending on the time required until the air flow control by the first air flow control means becomes substantially effective. Therefore, the speed at which the second air flow rate control means changes the air supply amount or the exhaust gas amount in the stop process or start process of the supply air or the stop process or start process of the exhaust (the operation of the second air flow control means). (Speed) is set according to factors such as the volume of the room, the airtightness of the room, and the operating speed of the first air flow control means.

  In the present invention, the second air flow control means is a means for opening and closing the air supply passage or the exhaust passage at a constant speed, such as the damper described above, and the first air flow control means is also the above-mentioned. In the case of a means for freely opening and closing the exhaust passage or the air supply passage, such as a damper, the time required for the control from the fully open to the fully closed or the fully closed to the fully open of the second air flow rate control means, It is preferable that it is 10 to 60 times the shortest time from the full opening to the full closing of the first air flow control means, or the time required for the control of the second air flow control means is 180 seconds or more. .

  If the time required for the control of the second ventilation amount control means is less than the above range or 180 seconds, the chamber pressure may fluctuate greatly, and the chamber pressure may not be maintained at the set value. Further, if the time required for the control of the second air flow rate control means is larger than the above range, unnecessary time is required for stopping and starting the supply of air into the room or stopping and starting the exhaust from the room. Is undesirable.

  In the means for opening and closing the air supply passage or the exhaust passage at a constant speed, by adjusting the gear ratio of the gear that transmits the drive of the drive means such as a motor to the blades in the damper and the valve, and the energization ratio of the drive means The time required for the control can be controlled, and the air blowing means can control the time required for the control by adjusting the rotation speed of the blades.

  In the present invention, other means than the above-described means may be used as necessary. Such other means include, for example, an air purification means for removing contaminants in the air, an air conditioner that adjusts temperature, humidity, etc., and supplies the air supply passage, a blower means, and an air supply passage. An air supply passage provided upstream of the second air flow control means or the first air flow control means, or downstream of the first air flow control means or the second air flow control means in the exhaust passage. Or well-known means, such as an airtight damper which can close an exhaust passage hermetically, is mentioned.

  The present invention is applied to all fields requiring control of room pressure, such as pharmaceutical factories and semiconductor manufacturing factories.

  The room pressure control system of the present invention has a chamber pressure detecting means for detecting the atmospheric pressure of a room in which air of a predetermined flow rate is supplied from the air supply passage and is discharged to the exhaust passage, and a detection value by the chamber pressure detecting means is set. A first air flow rate control means for controlling the air flow rate of the exhaust passage or the air supply passage so as to be kept at the value, and the process of stopping or starting the supply of air to the room, or stopping the exhaust from the room A second air flow rate control means for changing the air flow rate of the air supply passage or the air flow rate of the exhaust passage in the process or the start process, and the second air flow rate control means is a process of stopping the air supply to the room Alternatively, in the starting process, or in the process of stopping or starting the exhaust from the room, the first ventilation amount control means receives the detection value from the chamber pressure detection means and controls the ventilation amount of the exhaust passage or the ventilation amount of the supply passage. The first air flow control is the time until the detection value is received again. The air flow rate corresponding to the control deviation allowed by the first air flow rate control means, the air flow rate of the air supply passage or the air flow rate of the exhaust passage changed by the second air flow rate control means, which changes during one control cycle. Therefore, the chamber pressure is set to the set value in the stop process or start process of the supply air or in the stop process or start process of the exhaust gas. Can keep.

  In the present invention, the second ventilation amount control means is a means for opening and closing the supply passage or the exhaust passage at a constant speed, and the first ventilation amount control means freely opens and closes the exhaust passage or the supply passage. The time required for the control from the fully open to the fully closed state of the second air flow rate control means or from the fully closed state to the fully open state is 10 to 10 times the shortest time from the fully open to the fully closed state of the first air flow amount control means. If it is 60 times, it is more effective in applying the present invention to a system in which a plurality of rooms are connected in parallel to the air supply passage and the exhaust passage, and the supply air stop process or start process It is even more effective to keep the chamber pressure at a set value in the stop process or start process of exhaust.

  In the present invention, the second ventilation amount control means is a means for opening and closing the supply passage or the exhaust passage at a constant speed, and the second ventilation amount control means is fully opened to fully closed or fully closed to fully opened. When the time required for the control up to 180 seconds or more is more effective in applying the present invention to a system in which a plurality of rooms are connected in parallel to the air supply passage and the exhaust passage, In addition, it is more effective in keeping the chamber pressure at the set value in the supply air stop process or start process or the exhaust stop process or start process.

  In the present invention, the air supplied to the room from the air supply passage is the air purified by the air purifying means for removing contaminants in the air. Can be applied.

<First embodiment>
As an embodiment of the present invention, FIG. 1 shows a system for controlling a chamber pressure by controlling an exhaust amount corresponding to an air supply amount.

  The room pressure control system in the present embodiment is connected to any one of the supply passages 101 and 102, and is divided into a plurality of rooms connected to any one of the exhaust passages 103 and 104. Intra-compartment differential pressure transmitter 1 that is a chamber pressure detecting means for detecting the air pressure in each compartment, and air exhausted from each compartment so that the detected value by each intra-compartment differential pressure transmitter 1 is maintained at a set value. A variable air volume control valve (VAV valve) 2 which is a first air flow control means for controlling the amount of air flow, and a second for changing the air supply amount to each compartment in the stop or start process of the air supply to each compartment And a variable stroke time control valve (VST valve) 3 which is a ventilation amount control means.

  The supply passages 101 and 102 are passages branched from the supply passage 100. In the air supply passage 100, for example, an air conditioner 10 driven by a transistor inverter composed of a cooling coil, a heating coil and a fan, a medium performance filter 11 which is a kind of air purification means, and the air pressure in the air supply passage 100 are detected. A differential pressure transmitter 12 installed in an air passage, which is an atmospheric pressure detecting means, and a constant air flow valve (CAV valve) 13 for maintaining the air supply amount of the air supply passage 100 at a predetermined flow rate are provided.

  The air supply passage 101 is a supply passage branched from the air supply passage 100 between the differential pressure transmitter 12 installed in the air passage and the CAV valve 13, and the five compartments A to E are arranged in parallel. It is an air supply path connected to. The air supply passage 101 includes a CAV valve 14 that maintains the air supply amount of the air supply passage 101 at a predetermined flow rate, a high airtight damper 15 that can shut off the air supply passage 101 in an airtight manner, and an A to E section. Five VST valves 3 provided corresponding to the respective sections of the sections, and five high-performance filter-equipped air supply units constituting the outlets of the respective sections corresponding to the respective sections from the A section to the E section 16 are provided.

  The air supply passage 102 is an air supply passage branched from the air supply passage 100 between the differential pressure transmitter 12 installed in the air passage and the CAV valve 13 in the same manner as the air supply passage 101. It is a connected air supply passage. The air supply passage 102 includes a CAV valve 17 that maintains the air supply amount of the air supply passage 102 at a predetermined flow rate, a high airtight damper 18 that can shut off the air supply passage 102 in an airtight manner, and the VST valve 3. And a high-performance filter-equipped air supply unit 19 that constitutes the outlet of the F section.

  The exhaust passage 103 is an exhaust passage that connects four sections of the A section, the B section, the C section, and the F section in parallel. In the exhaust passage 103, an indoor-installed filter-equipped exhaust unit 20 that constitutes the suction port of the A section, and a ceiling-installed filter-equipped exhaust unit 21 that constitutes the respective suction ports of the other three sections, A VAV valve 2 provided corresponding to each of the four sections, a highly airtight damper 22 capable of airtightly blocking the exhaust passage 103, and an exhaust fan 23 are provided.

  The exhaust passage 104 is an exhaust passage that connects two sections of the D section and the E section in parallel, is connected to the supply side of the air conditioner 10, and is an exhaust passage that returns the exhaust of these sections to the air conditioner 10. It is. In the exhaust passage 104, the indoor-installed filter-equipped exhaust unit 24 that constitutes each suction port of each compartment, the VAV valve 2 provided corresponding to each compartment, and the exhaust passage 104 are shut off in an airtight manner. A highly airtight damper 25 and a return air fan 26 that can be used are provided.

  An outside air supply passage 105 for supplying outside air is connected to the air supply side of the air conditioner 10. Moreover, the exhaust fan 23 and the return air fan 26 do not have an inverter, but are air blowing means that operates at a constant air volume.

  The air pressure differential pressure transmitter 12 is a device that detects the air pressure in the air supply passage 100 and transmits the detected value to the intra-compartment differential pressure transmitter 1 as an electrical signal. The intra-compartment differential pressure transmitter 1 detects the compartment pressure in the compartment, receives an electric signal from the differential pressure transmitter 12 installed in the air passage, and converts the pressure between the air pressure in the supply passage 100 and the compartment pressure in the compartment. It is a device that transmits a corresponding electrical signal to the VAV valve 2. The differential pressure transmitter 12 installed in the air passage also transmits the detected value of the air pressure in the air supply passage 100 to the air conditioner 10 as an electrical signal.

The VAV valve 2 is a variable air volume control valve that automatically adjusts the air volume in accordance with an electrical signal corresponding to the differential pressure sent from the intra-compartment differential pressure transmitter 1. The VAV valve 2 controls the butterfly valve, a motor for driving the blades of the butterfly valve, a gear for transmitting the rotational drive of the motor to the butterfly valve, and the opening degree of the butterfly valve according to the electric signal. And feedback control means. In the motor, the time required for the rotation shaft of the motor to rotate 90 degrees is about 0.3 seconds, for example, and the gear ratio of the gear is about 1/100. In this case, the time required for the VAV valve 2 to rotate the butterfly valve by 90 degrees (the shortest time from fully open to fully closed, hereinafter also referred to as “stroke time”) is set to about 30 seconds.

  The VST valve 3 is a variable stroke time control valve that changes the amount of air supply at a predetermined speed in the air supply stop process or start process. The VST valve 3 includes a butterfly valve, a motor that drives the blades of the butterfly valve, a gear that transmits the rotational drive of the motor to the butterfly valve, and an energization control unit that controls the energization ratio of the motor. ing. In the motor, the time required for the rotation shaft of the motor to rotate 90 degrees is about 0.3 seconds, for example, and the gear ratio of the gear is about 1/600.

  The energization control means is a potentiometer that outputs a voltage proportional to the position of the slider that contacts and moves a resistance to which a voltage is applied at both ends, and energizes the motor and interrupts the motor in proportion to the resistance value of the potentiometer. The power switching element that transmits an operation signal that repeats alternately at the pulse interval, and the transistor relay that operates to turn on and off the motor in accordance with the operation signal.

  In this case, the stroke time of the VST valve 3 is about 180 seconds when the energization ratio is 100%, and becomes longer when the energization ratio is small, for example, about 1800 seconds when the energization ratio is 10%. As described above, the VST valve 3 appropriately adjusts the energization ratio of the motor by energizing and shutting off the motor, so that the required time from fully open to fully closed or from fully closed to fully open at the time of control is 180 seconds or more. It is possible to control at a desired time.

  The CAV valves 13, 14, and 17 correspond to the amount of air supply that decreases due to an increase in pressure loss due to the clogging of the high-performance filter provided in the high-performance filter-equipped air supply units 16 and 19 over time. This is a constant air flow valve that increases the air supply amount in the air supply passage, compensates for a decrease in the air supply amount due to an increase in pressure loss, and maintains a predetermined air supply amount. The high airtight dampers 15, 18, 22, and 25 are dampers having a stroke time of about 20 to 30 seconds. The air supply units 16 and 19 with a high performance filter and the exhaust units 20, 21 and 24 with a high performance filter are units equipped with a high performance filter as an air purification means.

  The operating state of the room pressure control system of the present embodiment will be described. First, the operating state of the system in a steady state where air of a predetermined flow rate is supplied to each section will be described.

  In the present embodiment, the compartments A to F have different compartment volumes as shown. The volume of the section is set according to the work in the section, for example. Each of these compartments is a compartment in which the required cleanliness is different from the adjacent compartment, and the room pressure of each compartment is set according to the required cleanliness. The set value of the chamber pressure in each section is determined by the differential pressure between each section and the air supply passage 100. In the present embodiment, the setting value of the chamber pressure in the A section is 20 Pa, the setting value of the chamber pressure in the B section is 0 Pa, the setting value of the chamber pressure in the C section is 10 Pa, and the chamber pressure in the D section Is set to 20 Pa, the set value of the chamber pressure in the E section is 40 Pa, and the set value of the chamber pressure in the F section is 20 Pa. In the steady state operation of the present embodiment, the high airtight dampers 15, 18, 22, 25 and the VST valve 3 are fully opened.

  Outside air is supplied from the outside air supply passage 105 to the air conditioner 10. The return air is supplied to the air conditioner 10 from an exhaust passage 104 described later. The air supplied to the air conditioner 10 is adjusted in temperature and humidity and sent to the medium performance filter 11. The medium performance filter 11 removes dust from the air.

  The air supply amount in the air supply passage 100 is controlled by the power source frequency by the transistor inverter in the air conditioner 10 so that the detected value by the differential pressure transmitter 12 installed in the air passage is maintained at a predetermined value. It is determined by controlling the number.

  The clean air in the air supply passage 100 from which the temperature and humidity are adjusted and the dust is removed is sent to the CAV valves 13, 14, and 17. The CAV valve 13 passes clean air having a predetermined flow rate required for other sections connected to the downstream side, a low dew point air production apparatus, and the like. The CAV valve 14 supplies clean air having a predetermined flow rate required to maintain the chamber pressure from the A section to the E section to the supply passage 101. The CAV valve 17 supplies the supply air passage 102 with a predetermined flow rate of clean air required to maintain the chamber pressure in the F section.

  Thus, the set value of the room pressure is maintained in each section from the A section to the F section by controlling the supply amount of the supply passage 100 by the air conditioner 10 and controlling the supply amount by each CAV valve. A sufficient flow rate of air is constantly supplied.

  The clean air supplied to the air supply passage 101 passes through the high performance filter of the air supply unit 16 with a high performance filter and is supplied from the A section to each section of the E section. As described above, clean air having a predetermined flow rate is supplied from the air supply passage 101 to each of the sections A to E.

  Similarly, the clean air supplied to the air supply passage 102 is supplied to the F section through the high performance filter of the air supply unit 19 with a high performance filter. As described above, clean air having a predetermined flow rate is supplied from the air supply passage 102 to the F section.

  The intra-compartment differential pressure transmitter 1 detects the room pressure of each compartment and transmits an electrical signal corresponding to the difference from the detected value of the differential pressure transmitter 12 installed in the air passage to the VAV valve 2. The VAV valve 2 receives an electrical signal corresponding to the difference in pressure difference between the chamber pressure and the air pressure in the air supply passage 100, so that the pressure difference obtained from the detected value becomes a set value. The operation amount is obtained by the PID operation, and the exhaust amount is controlled.

  By controlling the exhaust amount of the VAV valve 2 as described above, in each section from the A section to the E section, an amount corresponding to the amount of air supplied to each section so that the chamber pressure in each section is maintained at a desired value. Are exhausted from each compartment through the high performance filters of the exhaust units 20, 21, 24 with high performance filters. In this way, the chamber pressure in each of the sections A to E is maintained constant corresponding to the set value.

  Similarly, by controlling the exhaust amount of the VAV valve 2 as described above, in the F section, an amount of air corresponding to the amount of air supplied to the F section is maintained so that the chamber pressure in the F section is maintained at a desired value. Then, the air is discharged from the F section through the high performance filter of the exhaust unit 21 with a high performance filter. In this way, the chamber pressure in the F section is kept constant corresponding to the set value.

  The control cycle of the VAV valve 2, that is, the electric signal is input to the VAV valve 2, the control deviation from the set value is obtained, the operation amount of the VAV valve 2 is obtained, and the VAV valve 2 is operated. The time until the electric signal is input to the VAV valve 2 again is about 300 milliseconds.

  The air discharged from the A section, the B section, the C section, and the F section passes through the exhaust passage 103 and is discharged from the exhaust fan 23 to the outside air. The air discharged from the D section and the E section passes through the exhaust passage 104 and is sent from the return air fan 26 to the air conditioner 10. The return air sent from the return air fan 26 to the air conditioner 10 is reused as clean air for supplying air.

In the system of the present embodiment, the outside air from the outside air supply passage 105 is taken in to compensate for the change in the return air amount and secure the supply air amount. Although the minimum outside air supply amount is set according to the change amount of the return air, the change amount of the return air can be set in advance. In the embodiment, the minimum outside air supply amount is secured.

  Next, an operation state of the system according to the present embodiment for stopping the supply of air from the steady state to the desired compartment in order to perform repairs, sterilization, and the like of the desired compartment will be described. The VST valve 3 is set with a stroke time that does not affect the control operation of the VAV valve. The stroke time of the VST valve 3 may be set to a different time for each VST valve 3 in accordance with the volume and airtightness of each section, or for all the VST valves 3 in the section requiring the latest stroke time. The stroke time of the corresponding VST valve 3 may be set.

  As described above, the VST valve 3 is held in a fully open state in a steady state. When repairing or sterilizing a desired section, the VST valves 3 having the same supply passage as that of the target section are collectively operated from fully open to fully closed. The VST valve 3 on which this operation is performed closes at a slower speed than the stroke time of the VAV valve 2 according to the set stroke time.

  While the VST valve 3 is closed, the air supply amount of the air supply passages 101 and 102 does not change, but the air supply amount to the section corresponding to the VST valve 3 decreases, and the detected value of the chamber pressure also decreases. The VAV valve 2 corresponding to the closed VST valve 3 operates in a direction in which the exhaust amount decreases so that the chamber pressure is maintained constant based on the set value in accordance with the decrease in the detection value described above.

  Since the VST valve 3 operates slowly in the above-described stroke time, the amount of change in the amount of air supplied to the compartment that changes during one control cycle of the VAV valve 2 is small, and the change in the amount of air supplied corresponds to this change. The change in the changing chamber pressure is small. Therefore, during one control cycle of the VAV valve 2, the chamber pressure changes only to the extent that it can be restored to the set value only by operating the VAV valve 2. Therefore, the chamber pressure in the compartment corresponding to the VST valve 3 is kept constant until the VST valve 3 is fully closed.

  When it is confirmed that the VST valve 3 is fully closed, the corresponding highly airtight damper is operated to be fully closed, and the target section is completely shut off.

  When the repair, sterilization, or the like is completed, the high airtight damper is operated from fully closed to fully open, and the VST valve 3 is collectively operated from fully closed to fully open. The VST valve 3 opens at a slower speed than the stroke time of the VAV valve 2 according to the set stroke time. As in the case of the closing operation of the VST valve 3, the chamber pressure changes only to the extent that it can be restored to the set value only by operating the VAV valve 2 during one control cycle of the VAV valve 2. Therefore, the chamber pressure in the compartment corresponding to the VST valve 3 is kept constant until the VST valve 3 is fully opened.

  In the present embodiment, the high airtight damper is provided corresponding to the air supply passages 101 and 102 and the exhaust passages 103 and 104, but the high airtightness is provided corresponding to each VST valve 3 and VAV valve 2. When the damper is provided, it is possible to stop or start the supply of air only in a specific section of the same supply system while maintaining the chamber pressure.

  Further, regarding the control of the rotational speed of the exhaust fan 23, it is conceivable to control by the opening degree of the VAV valve 2 and the differential pressure of the exhaust passage (for example, the differential pressure between the pressure of the exhaust passage and the atmospheric pressure). When the exhaust amount is controlled as described above, the control of the VAV valve 2 and the control of the rotational speed of the exhaust fan 23 may interfere with each other and cause hunting. From this point of view, in the present embodiment, the rotational speed of the exhaust fan 23 is not controlled.

  In the present embodiment, the intra-compartment differential pressure transmitter 1 is configured to transmit an electrical signal corresponding to the differential pressure between the chamber pressure of each compartment and the air pressure of the air supply passage 100. For example, each of the intra-compartment differential pressure transmitter 1 and the air pressure differential pressure transmitter 12 transmits an electrical signal corresponding to the detected value to the VAV valve 2, and the VAV valve 2 detects the detected value from the detected value. It is good also as composition which asks for differential pressure.

  Further, in the present embodiment, the air supply amount to each section is controlled by the VST valve 3 in the supply air stop process or start process. Such a configuration is suitable when the chamber pressure is positive, but in the present invention the chamber pressure may be negative. In the case where the chamber pressure is maintained at a negative pressure, it is also possible to maintain the chamber pressure constant according to the rotation speed of the fan of the air conditioner 10 in the supply air stop process or start process.

  The chamber pressure control system in this embodiment is a VST valve that opens and closes at a speed that does not affect the control of the exhaust amount in a system that controls the chamber pressure by maintaining a predetermined air supply amount and controlling the exhaust amount. Since 3 is provided, it can be controlled to maintain the chamber pressure in the supply air stopping process or starting process by controlling the chamber pressure in the steady state. Therefore, the chamber pressure can be maintained at the set value during the supply stop process or the start process, and even when a plurality of rooms are connected in parallel to the supply passage and the exhaust passage, Cross contamination (cross contamination) can be prevented.

  Further, the room pressure control system in the present embodiment is capable of supplying clean air to a plurality of rooms and maintaining the room pressure set individually for each room in any case during supply. Therefore, it can be applied to facilities that require a strict clean environment such as pharmaceutical factories and semiconductor factories.

<Second Embodiment>
As another embodiment of the present invention, FIG. 2 shows a system for controlling the air supply amount corresponding to the exhaust amount to control the chamber pressure to a negative pressure.

  In the room pressure control system of the present embodiment, the CAV valves 13, 14, and 17 are removed, and the supply passage 101 is provided with VAV valves 32 corresponding to the five sections A to E, and the supply passage 102. Is provided with a VAV valve 32 corresponding to the F section, and the exhaust passage 103 is provided with VST valves 33 corresponding to the four sections A to C and F, and the high airtight damper 22 and the exhaust fan 23 A CAV valve 34 is provided between the high airtight damper 25 and the return air fan 26, and a VST valve 33 corresponding to each of the two sections D and E is provided in the exhaust passage 104. 37, the exhaust fan 23 and the return air fan 26 are transistor inverter drive fans, the power frequency is controlled by the transistor inverter, and the total ventilation amount of the exhaust passage 103 and the exhaust passage 104 are controlled. Besides controlling the total amount of aeration is configured similarly to the chamber pressure control system of the first embodiment.

  In the room pressure control system of the present embodiment, the exhaust amount of each section A to C and F is kept constant by the exhaust fan 23 and the CAV valve 34, and each of D and E is controlled by the return air fan 26 and the CAV valve 37. The displacement of the compartment is kept constant. On the other hand, the amount of air supplied to each compartment is determined by the electric pressure sent from the intra-compartment differential pressure transmitter 1 with the chamber pressure for each compartment set to a negative pressure relative to the air pressure in the air supply passage 100. It is automatically controlled by the VAV valve 32 to maintain.

  In the exhaust stop process and exhaust start process, the VST valve 33 is operated in the same manner as in the first embodiment. Accordingly, the exhaust can be stopped and the exhaust can be started in a state where the chamber pressure in each section is maintained at a negative pressure with respect to the air pressure in the supply passage 100.

In the present embodiment, the three chambers A, B, and C are connected in parallel by the same air supply passage and are connected in parallel by the same exhaust passage, as shown in FIG. An experimental facility constructed similar to the system was used. The volume of chamber A is 16.45 m ³ , the volume of chamber B is 16.45 m ³ , and the volume of chamber C is 10.71 m ³ . A clean air having a predetermined flow rate is supplied to each chamber, and the chamber pressure in each chamber is maintained at a predetermined value by controlling the exhaust amount by the VAV valve. In this experimental facility, the VST valve corresponding to room A was closed with a stroke time of 1080 seconds. The chamber pressure in each chamber at this time is shown in FIG. 3, and the air supply amount and the exhaust amount in each chamber at this time are shown in FIG.

  When the VST valve is closed with a stroke time of 1080 seconds, as shown in FIG. 3, the chamber pressure in each chamber is kept constant before the VST valve closing operation, in the closing process, and after the closing operation. In addition, when the VST valve is closed with a stroke time of 1080 seconds, as shown in FIG. 4, there is no reversal between the air supply amount and the exhaust amount in each chamber, and the chamber pressure is kept constant in each chamber. The balance between the amount of air supplied and the amount of exhaust is appropriately maintained.

<Comparative example>
Using the same experimental facility as in Example 1, the VST valve corresponding to room A was closed with a stroke time of 20 seconds. The chamber pressure in each chamber at this time is shown in FIG. 5, and the air supply amount and the exhaust amount in each chamber at this time are shown in FIG.

  When the VST valve was closed with a stroke time of 20 seconds, as shown in FIG. 5, the order of the chamber pressures in each chamber was not reversed, but the chamber pressure varied greatly. Further, when the VST valve is closed in a stroke time of 20 seconds, as shown in FIG. 6, the reversal of the air supply amount and the exhaust amount is observed in each chamber, and the chamber pressure is kept constant in each chamber. Therefore, the balance between the air supply amount and the exhaust amount is temporarily lost.

It is a schematic block diagram which shows one embodiment of this invention. It is a schematic block diagram which shows other embodiment of this invention. It is a figure which shows the chamber pressure of each chamber when the VST valve corresponding to the A room of the experimental facility shown in the Example of this invention is closed from a steady state by stroke time 1080 seconds. It is a figure which shows the air supply amount and exhaust_gas | exhaustion amount of each chamber when the VST valve corresponding to the A room of the experimental facility shown in the Example of this invention is closed from a steady state by stroke time 1080 second. It is a figure which shows the chamber pressure of each chamber when the VST valve corresponding to the A room of the experimental facility shown in the Example of this invention is closed from a steady state by stroke time 20 second. It is a figure which shows the air supply amount and exhaust_gas | exhaustion amount of each chamber when the VST valve corresponding to the A room of the experimental facility shown in the Example of this invention is closed from a steady state in 20 second of stroke time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Differential pressure transmitter in a section 2, 32 VAV valve 3, 33 VST valve 10 Air conditioner 11 Medium performance filter 12 Differential pressure transmitter 13, 14, 17, 34, 37 CAV valve 15, 18, 22, 25 High airtight damper 16, 19 Supply unit with high-performance filter 20, 21, 24 Exhaust unit with filter 23 Exhaust fan 26 Return air fan 100-102 Supply passage 103, 104 Exhaust passage 105 Outside air supply passage

Claims (3)

A chamber pressure detecting means for detecting a chamber pressure which is a pressure of a room in which air of a predetermined flow rate is supplied from the supply passage and is discharged to the exhaust passage;
It is means for controlling the air flow rate of the exhaust passage or the air supply passage according to the detection value from the chamber pressure detection means, and the chamber pressure is set by repeating this control every control cycle. A first air flow control means for maintaining the value;
In the process of stopping or starting the supply of air to the room, or stopping or starting the exhaust from the room, the amount of ventilation of the supply passage or the amount of ventilation of the exhaust passage is determined at a predetermined speed. Second air flow rate control means for controlling the supply passage or the exhaust passage by opening and closing the supply passage or the exhaust passage at a constant speed over a required time set to change;
Passage pressure detection means for detecting the pressure of the exhaust passage or the supply passage in which the ventilation amount is controlled by the second ventilation amount control means;
A first air blowing means which is provided in the exhaust passage or the air supply passage where the air flow is controlled by the first air flow control means, and which operates at a constant air flow;
In the exhaust passage or the air supply passage in which the ventilation amount is controlled by the second ventilation amount control unit, the second ventilation unit capable of changing the air volume according to the detection value from the passage atmospheric pressure detection unit, Have
The rate of change in the air flow rate by the second air flow rate control means when the air supply passage or the exhaust passage is opened and closed over the required time over the required time is the air flow by the first air flow rate control means. Since the required time is set in advance so as to be less than the rate of change in the amount, the rate of change in the amount of ventilation controlled by the second amount of ventilation control means is changed to the chamber pressure due to the change in amount of ventilation. The chamber pressure is characterized in that the first ventilation rate control means has a rate of change in ventilation rate that falls within a range in which the chamber pressure can be maintained at a set value in the one control cycle. Control system.   In the one control cycle, the first ventilation amount control means receives the detection value from the chamber pressure detection means, controls the ventilation amount of the exhaust passage or the ventilation amount of the supply passage, and again sets the detection value. The room pressure control system according to claim 1, which is a time until receiving.   The range within which the set value can be maintained means that the first ventilation amount control means can maintain the chamber pressure at the set value independently during the previous control period. The room pressure control system according to claim 1, wherein the room pressure control system is within a range of deviation from the detected value.

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