JP2006329440A - Pressure control unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively control indoor pressure even under a condition of little air volume. <P>SOLUTION: This pressure control unit comprises a plurality of blowers 16 arranged in series in a casing 14 formed on the way of a duct 12 where the air in a room 40 is circulated, for making a discharge pressure of the air variable, and arranged in parallel with each other in the casing 14 for making the air volume variable, and a control unit 18 combined with the blowers 16 and controlling the indoor pressure by adjusting the discharge pressure or air volume. Here, a detection value of a pressure sensor 50 in the room 40 is input to the control unit 18, and the output of the blowers 16 is adjusted on the basis of the detection value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention particularly relates to a pressure control unit that effectively controls the indoor pressure of a room such as a clean room or a closed space.

  A clean room used in a semiconductor manufacturing factory, an operating room, a food factory, or the like has a plurality of performance levels set according to required cleanliness. In this clean room, an air ventilation path including an air supply duct and an exhaust duct is formed. A filter is installed in the air supply duct of the ventilation path to remove dust, microorganisms and the like contained in the air supplied from the outside, and the purified air is supplied indoors to maintain the cleanliness of the room.

  By the way, when the inside of the clean room has a negative pressure, contaminated air may flow from the outside and contaminate the room. For this reason, it is necessary to measure the pressure inside and outside the clean room with a differential pressure gauge arranged in the room and to control the pressure in the room so that the room does not become a negative pressure.

  FIG. 4 is a diagram showing a schematic configuration of a conventional pressure control system. As shown in the figure, the pressure control system 1 is a system that adjusts the amount of air supplied to the room 2 with a multiblade fan 4 attached to the air supply duct 3. The room pressure in the room 2 is controlled by operating the multiblade fan 4 with the controller 6 so that the pressure detected at the pressure monitoring point 5 becomes a preset reference pressure.

As such a pressure control system, for example, in Patent Document 1, an air conditioner and an exhaust device are provided in a clean room, and negative pressure is generated in the clean room based on a detection value of a sensor that measures a differential pressure between the clean room and the outside. It is disclosed that the operation of the blower fan is controlled so as not to occur.
JP-A-6-94261

  However, the multi-blade fan used in the pressure control system has a configuration in which the supply air volume can be changed in multiple stages, such as strong, medium, and weak, and a small supply air volume from the viewpoint of saving energy or reducing system operating costs. May be supplied into the room to control the pressure in the room.

  In order to obtain a small amount of air supply, it is necessary to reduce the flow rate of the multiblade fan installed in the duct. In this case, for example, in the case of a multi-blade fan that can adjust the air volume in a room with a single unit, the supply capacity is large. A so-called surging phenomenon may occur in which normal air supply operation cannot be performed due to the pressure pulsation. In this case, even if the smallest multi-blade fan is used, surging occurs, and the pressure in the room becomes unstable, making it difficult to maintain a positive pressure.

  SUMMARY OF THE INVENTION In order to solve the problems of the prior art, it is an object of the present invention to effectively control the indoor pressure even under a slight air flow condition.

The pressure control unit of the present invention is arranged in series in a casing formed in the middle of a duct through which indoor air circulates to vary the discharge pressure of the air, and is arranged in parallel in the casing to provide an air volume of the air. And a control means for controlling the pressure in the room by adjusting the discharge pressure or the air volume by combining the blowers.
In this case, a detection value of the indoor pressure sensor is input to the control means, and an output of the blower is adjusted based on the detection value.

  The present invention as described above is a blower that has a smaller air flow and discharge pressure than a multi-blade blower used in conventional air conditioners, but does not generate surging even with a small air flow and has a stable operating state. Multiple units are installed in series or in parallel on the duct. Further, the detection value of the indoor pressure sensor is input to the control means. For this reason, by controlling the operating frequency of each blower by combining the number of blowers based on the measured pressure in the room, it is possible to perform stable indoor pressure control even with a small air volume of the blower.

Embodiments of the pressure control unit of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a diagram showing a schematic configuration of a pressure control unit according to the embodiment.
As illustrated, the pressure control unit 10 is formed in the middle of a duct 12 connected to a room such as a clean room or a closed container. The duct 12 forming the pressure control unit 10 may be either an air supply duct or an exhaust duct.

  The pressure control unit 10 basically includes a casing 14, a blower 16 installed in the casing 14, a control unit 18 serving as a control means for controlling the blower 16, and a volume damper 20 capable of finely adjusting the air volume. It is configured.

  The casing 14 is formed in the middle of the duct 12 through which the indoor air circulates, and is formed in a substantially rectangular parallelepiped shape having a larger diameter than the duct 12 so that air is circulated therein. Both ends of the casing 14 are formed in a substantially funnel shape so as to be connected to the opening of the duct 12. A pair of openings 14 a and 14 b at both ends of the casing 14 are connected to the duct 12. The casing 14 may be formed in a rectangular parallelepiped shape, an elliptical shape, a cylindrical shape, or the like.

For the blower 16 according to the embodiment, for example, an axial fan can be used. The axial fan passes gas in the axial direction of the impeller. For this reason, the axial fan has a smaller installation space and is more compact than the multi-shaft fan, but has a smaller air volume and discharge pressure than the multi-blade fan. However, even when the axial fan supplies a small air volume of 100 m ³ / h or less, surging does not occur and the operating state is stable.

A plurality of blowers 16 are installed in the casing 14 in series or in parallel with respect to the air flow direction. In the present embodiment, two fans 16 are arranged in series inside the casing 14, and further, two fans 16 arranged in parallel are installed in two places, for a total of six. For convenience of explanation, the blower 16 is assumed to be 16a, 16b, 16c, 16d, 16e, and 16f in order from the right to the left in FIG. Moreover, the quantity of the air blower 16 is not limited to this, The setting number can be changed arbitrarily according to the amount of indoor process air.
When two fans 16c, 16d or 16e, 16f are arranged in parallel, the size of the blower 16c covers the section of the casing 14, and no gap is generated.

  On the other hand, when the blower 16a or 16b is arranged in series, the blower 16 is smaller than the cross section of the casing 14, and therefore a gap is generated between the blower 16 and the casing 14. A closing wall 22 for blocking air flow is formed in the gap. Thereby, the air in the casing 14 is ventilated through the blower 16, and it is possible to prevent the air from flowing back around the blower 16.

  The control unit 18 is connected to a plurality of blowers 16 arranged in the casing 14 so as to control the number of fans 16 operated and the operation frequency of each fan 16. The control unit 18 is formed outside the casing 14. The control unit 18 is connected to a pressure sensor that detects the indoor pressure, which will be described later.

  FIG. 2 shows the relationship between the air volume and the discharge pressure when the control unit 18 controls the plurality of blowers 16. In the graph of the figure, the vertical axis represents the discharge pressure of the blower, the horizontal axis represents the air volume of the blower, and the control limit when the number of operating fans 16 is controlled is displayed. When operating frequency (output) control of the blower 16 is performed, it is possible to operate with an air volume and discharge pressure lower than the control limit.

First, a line A indicates a control limit when only the blower 16a or 16b is operated. The minimum control range of this pressure control unit 10 is shown.
Line B shows the control limit when the fans 16c, 16d or 16e, 16f arranged in parallel are operated. At this time, the maximum value of the discharge pressure is substantially the same as that of the line A, but the air volume is doubled. This is thought to be due to the fact that the blower area was doubled by arranging the blowers 16 in parallel.

Line C indicates the control limit when the fans 16a and 16b arranged in series are operated. At this time, the maximum value of the air volume is substantially the same as that of the line A, but the discharge pressure shows a double value. This is considered because the output has doubled with respect to a fixed ventilation area by arrange | positioning the air blower 16 in series.
A line D indicates a control limit when the fans 16c, 16d, 16e, and 16f arranged in parallel and in series are operated. As shown in the figure, both the discharge pressure and the air volume are approximately twice as large as those of the line A.

  Since the air blower 16 used in the present invention has a smaller air volume and discharge pressure than a multiblade air blower, the air volume is controlled by combining a plurality of air blowers 16 arranged in series or in parallel and controlling the operation frequency of each air blower 16. The discharge pressure can be finely controlled. The blower 16 operates as a single unit of the blowers 16a and 16b, operates two fans 16a and 16b arranged in series, operates the fans 16c and 16d arranged in parallel or the fans 16e and 16f, and blowers 16c and 16d and fans 16e arranged in parallel. , 16f, the operation of 16c, 16d or 16e, 16f arranged in parallel with the fans 16a or 16b arranged in series, and the entire operation of the fans 16a to 16f can be arbitrarily selected.

  The volume damper 20 is an adjustment valve that is installed at either one of both ends of the casing 14 and can finely adjust the air volume of the air flowing through the casing 14. The volume damper 20 is connected to the control unit 18 so that the air volume can be controlled by the control unit 18.

  Next, FIG. 3 shows a schematic configuration of a pressure control system 30 using the pressure control unit 10 of the present invention. As shown in the figure, the pressure control system 30 is connected with an air supply duct 12a for supplying air into the room 40 and an exhaust duct 12b for exhausting air. The pressure control unit 10 described above is installed in the middle of the pipeline of the air supply duct 12a. The pressure control unit 10 may be arranged in the exhaust duct 12b.

  A pressure sensor 50 for detecting pressure is installed in the room 40. The pressure sensor 50 is configured to output a detection signal to the control unit 18. The pressure sensor 50 can also add a function of detecting the outdoor pressure and outputting the difference from the pressure in the indoor 40 to the control unit 18.

  Next, a pressure control method with the above configuration will be described below. A pressure sensor 50 installed in the room 40 detects a pressure difference between the room pressure and the outside pressure. Then, the detection value of the pressure sensor 50 is output to the control unit 18. In the control unit 18, a reference value is set in advance so that the room 40 has a negative pressure. Based on the reference value and the detected value, a combination of a plurality of fans arranged in series or in parallel with the air circulation path is controlled. . For example, when adjusting the air volume, the combination of the blowers 16 operates the blowers 16 arranged in parallel. When adjusting the discharge pressure, the blower 16 arranged in series is operated. Further, the air flow can be finely adjusted by controlling the operating frequency of the selected blower 16. As a result, the indoor pressure can be controlled to be the reference pressure. Note that the volume of the air flowing through the casing may be controlled by the volume damper 20.

It is a figure which shows the structure outline of the pressure control unit which concerns on embodiment. It is a figure which shows the relationship between the discharge pressure of a pressure control unit, and an air volume. It is a figure which shows the structure outline of the pressure control system using a pressure control unit. It is a figure which shows the structure outline of the conventional pressure control system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ......... Pressure control system, 2 ......... Indoor, 3 ......... Air supply duct, 4 ......... Multi-blade fan, 5 ......... Pressure monitoring point, 6 ......... Controller, 10 ......... Pressure control Unit, 12 ......... Duct, 14 ......... Case, 16 ...... Blower, 18 ...... Control unit, 20 ......... Volume damper, 22 ......... Closed wall, 30 ...... Pressure control system, 40 .... Indoor, 50 ... Pressure sensor.

Claims (2)

A plurality of blowers that are arranged in series in a casing formed in the middle of a duct through which indoor air circulates to vary the discharge pressure of the air, and are arranged in parallel in the casing to vary the air volume of the air. When,
Control means for controlling the pressure in the room by adjusting the discharge pressure or the air volume in combination with the blower;
A pressure control unit comprising the pressure control unit. The pressure control unit according to claim 1, wherein a detection value of the indoor pressure sensor is input to the control unit, and an output of the blower is controlled based on the detection value.

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