JP6321527B2 - Air purifier with fan filter unit - Google Patents

Description

  The present invention relates to an air cleaning device including a fan filter unit that combines a blower (fan) and a filter and supplies clean air.

  Conventionally, as a typical air purifier used in clean rooms that require clean air such as semiconductor, liquid crystal and micromachine manufacturing factories, and pharmaceutical and cosmetics manufacturing factories, fan filter units (hereinafter referred to as “fan filter units”) Called "FFU"). That is, the FFU is used in an environment in which clean air is supplied, such as a clean room, local cleaning of a semiconductor manufacturing apparatus, a clean stocker, and a clean booth. In particular, FFU is effective in an application where high reliability is required and serious damage is caused when the supply of clean air is stopped.

  FFU is also used for air purifiers installed in manufacturing equipment rooms that require more clean air, such as ceilings of clean rooms that manufacture semiconductor wafers and liquid crystal panels, and the interior of manufacturing equipment installed in clean rooms. It is used as.

  As a prior art, Patent Document 1 discloses that a pressure in an apparatus equipped with an FFU is detected and feedback-controlled with respect to the FFU (Embodiment 12). Further, in Patent Document 2, when a power supply abnormality is determined for each FFU, the fan driving motor is rotated at the instruction rotational speed at the time of abnormality, and the operation is continued without stopping the FFU until maintenance, and the instruction rotation is performed. A technique is disclosed in which an alarm is issued when the difference between the number and the actual rotational speed exceeds a reference value.

JP 2009-180446 A JP 2014-126214 A

  Since the FFU is used for the ceiling part of the clean room and the manufacturing apparatus in the clean room as described above, if the FFU is abnormally stopped due to an abnormality in the fan or filter being used, the semiconductor manufacturing apparatus or the like is stopped. The semiconductor production line may stop.

  Therefore, the FFU is always required to perform stable continuous operation. Therefore, it is necessary to constantly monitor the operating state of the FFU so that the FFU does not reach a stopped state. In the unlikely event that the FFU stops abnormally, it is necessary to quickly identify the cause, remove the cause of the FFU stoppage, and restart the FFU at an early stage.

  The present invention provides an air cleaning device that monitors the operating state of an FFU so that the FFU does not reach a stopped state, and can detect the cause of the abnormality when the FFU stops abnormally.

  The present invention relates to a fan, a chamber surrounding the fan from above, a filter provided at a blower outlet of the fan, a pressure gauge for detecting the pressure in the chamber or an anemometer for detecting the wind speed of the fan filter unit, Using a fan filter unit equipped with a tachometer that detects the number of rotations, the pressure value detected by the pressure gauge or the wind speed value detected by the anemometer and the tachometer for the static pressure-wind speed characteristics of the fan filter unit. By comparing the actual operating point obtained from the rotational speed and the operating point during normal operation based on the initial pressure characteristics of the filter, the operating state of the fan filter unit is monitored to detect the cause of the abnormality.

  According to the present invention, in an air purifier equipped with an FFU, an abnormality that causes the FFU to stop is detected by monitoring the current operating state of the FFU, and if the FFU stops abnormally, the cause of the abnormality Can be detected promptly.

FIG. 1 is a cross-sectional view illustrating the configuration of the FFU according to the first embodiment. FIG. 2 is a characteristic diagram illustrating a state of the FFU in the first embodiment. FIG. 3 is a cross-sectional view illustrating the configuration of the FFU according to the second embodiment. FIG. 4 is a characteristic diagram illustrating the state of the FFU in the second embodiment.

  Hereinafter, Examples 1 and 2 will be described with reference to FIGS. 1 to 4 as embodiments of the present invention.

FIG. 1 is a cross-sectional view illustrating the configuration of the FFU according to the first embodiment. In FIG. 1, the FFU includes a fan 1, a chamber 2 that surrounds the fan 1 from above, and a filter 5 that is provided at the outlet of the fan 1. The pressure gauge 3 is attached to the chamber 2 and detects the pressure in the chamber 2. The tachometer 4 is provided, for example, at the top of the fan 1 as a position facing the rotation of the fan 1 and optically detects the rotation speed of the fan 1, for example. About this tachometer, you may divert not only the above but the rotation speed detection function mounted in the motor part of a fan motor. As a filter used for FFU, a HEPA filter is typical. Further, a DC brushless motor or an AC motor is used as the fan motor.

  Next, a state monitoring detection method according to the first embodiment will be described with reference to FIG. FIG. 2 is a characteristic diagram showing the state of the FFU based on actually measured values detected in the FFU of FIG. FIG. 2A shows the normal characteristics, and FIGS. 2B and 2C show the abnormal characteristics, respectively. 2A to 2C, the horizontal axis represents the wind speed (m / s) and the vertical axis represents the static pressure (Pa).

  Regarding the operating point of the FFU, in the normal characteristics shown in FIG. 2A, the initial pressure characteristic 8 of the filter and the static pressure-wind speed characteristic 9 of the FFU (hereinafter simply referred to as “fan characteristics 9”). The intersection 7 is a theoretical operating point during normal operation (hereinafter referred to as “normal operating point”). The initial pressure characteristic 8 of the filter is a filter initial value. The fan characteristic 9 is determined by the rotational speed of the fan as shown concentrically in FIG. 2. When the rotational speed increases, the radius of the arc increases and is positioned outward. Since the air volume is a product of the wind speed and the cross-sectional area of the flow path, if the cross-sectional area of the flow path is constant, the static pressure-air speed characteristics and the static pressure-air volume characteristics can be regarded as equivalent.

  In an actual FFU usage environment, the actual operating point 7 is the intersection of the pressure value 11 detected by the pressure gauge 3 and the fan characteristic 9 based on the rotational speed of the fan 1 detected by the tachometer 4. That is, the operating point actually obtained. The FFU operating state is monitored by comparing the actual operating point 7 with the normal operating point obtained from the filter initial value and the fan characteristic 9 (intersection of the filter initial pressure characteristic 8 and the fan characteristic 9). can do.

  The operating point 7 at the time of abnormality shown in FIG. 2B has a pressure value 11 lower than the operating point 7 during normal operation (FIG. 2A). Since this is a state in which the wind is lower than the pressure value of the filter initial value and easy to pass through, it can be determined that the filter 5 is broken if the pressure value drops below a certain level.

This certain degree can be changed as appropriate according to the amount of dust attached to the filter. Not only does the pressure value change according to the amount of dust or the like attached, but it also varies depending on the wind speed. For this reason, it is desirable to change a certain value depending on the relationship between the wind speed and the adhesion of dust or the like.
For example, in the case of a device whose pressure value changes by about 5% due to a change in wind speed, it is desirable to set a certain value as 20% and determine that it is in an abnormal state. In this case, even if it is affected by changes in wind speed, it can be determined that there is an abnormal state due to the adhesion of dust or the like.

  Also, if the pressure value changes only by about 1% due to changes in wind speed, and if the filter is operated with frequent changes in order to increase cleanliness, a certain value should be set as 5%. Can do. In this case, the influence of the wind speed is small, and the pressure change of the dust can be detected with high accuracy.

  Further, a certain value can be set as two stages. For example, when the value is 10%, the user can be notified as a caution state, and when the value is 15%, the user can be notified as an abnormal state. In this case, it is possible to know in advance the replacement time of the filter in operation, and the replacement filter can be prepared before it is determined to be abnormal.

  It is possible to detect an abnormality not only when the pressure decreases but also when the pressure increases. By setting a certain value to a low value of 3% or less, it is possible to determine a use state different from the normal state as an abnormal state. Further, at this time, it is desirable to display or notify the user that it is necessary to call a maintenance engineer instead of simply displaying an abnormality.

  The operating point 7 at the time of abnormality in FIG. 2C has a pressure value 11 that is higher than the operating point 7 at normal operation (FIG. 2A). This is a state in which the air flow is higher than the initial pressure value of the filter and is difficult for the air flow to pass. Therefore, if the pressure value rises above a certain level, it can be determined that the filter 5 is clogged.

  FIG. 3 is a cross-sectional view illustrating the configuration of the FFU according to the second embodiment. Components having the same reference numerals as those in FIG. 1 described above have the same functions, and thus description thereof is omitted. In the second embodiment, instead of the pressure gauge 3 in FIG. 1 in the first embodiment, an anemometer 6 is provided at an air intake port that the fan 1 takes in to detect the wind speed of the FFU.

  Next, a state monitoring detection method according to the second embodiment will be described with reference to FIG. FIG. 4 is a characteristic diagram showing the state of the FFU based on the actual measurement value detected in the FFU of FIG. FIG. 4A shows the normal characteristics, and FIGS. 2B and 2C show the abnormal characteristics. 4A to 4C, the horizontal axis represents the wind speed (m / s) and the vertical axis represents the static pressure (Pa).

  The operating point of the FFU is the same as that described with reference to FIG. As a characteristic during normal operation, the intersection of the initial pressure characteristic 8 (filter initial value) of the filter and the fan characteristic 9 shown in FIG. 4A is the theoretical operating point during normal operation.

  In an actual FFU usage environment, the actual operating point 7 is the intersection of the wind speed value 10 detected by the anemometer 6 and the fan characteristic 9 based on the rotational speed of the fan 1 detected by the tachometer 4. By comparing the actual operating point 7 with the operating point obtained from the filter initial value and the fan characteristic 9 (intersection of 8 and 9), the operating state of the FFU can be monitored.

  The operating point 7 at the time of abnormality of FIG.4 (b) has the wind speed value 10 raised with respect to the operating point 7 at the time of normal operation (FIG.4 (a)). This is because the wind is higher than the initial wind speed value of the filter and easy to pass through the wind (that is, the pressure value is low). If the wind speed value rises above a certain level, the filter 5 is damaged. Can be judged.

  The operating point 7 at the time of abnormality of FIG.4 (c) has the wind speed value 10 reduced with respect to the operating point 7 at the time of normal operation (FIG.4 (a)). This is a state in which the flow of air is lower than the initial wind speed value of the filter (that is, the pressure value is high). Therefore, if the wind speed value drops below a certain level, the filter 5 is clogged. It can be judged that

  In addition, since the air purifying device is configured by using one or more FFUs, in order to monitor the operating state as the air purifying device, a method of individually monitoring each operating state for each one or more FFUs is used. . Alternatively, in the case where the air purifying apparatus is configured by a certain number of FFUs, a method of comprehensively monitoring each FFU by a monitoring system that collectively manages them may be used.

According to the first embodiment and the second embodiment described above, when the FFU is abnormally stopped (for example, emergency stop due to the operation of the protection circuit), the operating point at that time is shown in the characteristic diagram of FIG. 2 or FIG. The cause of the abnormality can be identified by comparing with. In other words, depending on where the operating point at the time of abnormal stop is located on the fan characteristic 9 in FIG. 2 or FIG. 4, the cause of the abnormality such as filter clogging, filter breakage, or foreign matter entering the suction port may be caused. Can be detected.
Here, when foreign matter is mixed into the suction port, the rotational speed of the fan 1 decreases, so that the fan characteristic 9 in FIG. 2 or 4 shifts to the inner concentric circle and the operating point 7 is also located on the arc. become. By detecting the position, the cause of the abnormality (contamination of foreign matter) is determined.

  Further, the remaining time until the filter 5 reaches an abnormal state such as clogging, that is, the filter life, can be predicted by the position of the operating point 7 on the fan characteristic 9 in FIG. 2 or FIG. This filter life is determined by the final pressure loss (final pressure loss) of the filter. Since this closing pressure loss is a known value, when the pressure value at the current operating point 7 approaches the value obtained by adding the closing pressure loss to the pressure value at the operating point during normal operation, the filter will soon reach the end of its life. I can judge. Further, it is possible to predict the remaining time on the fan characteristic 9 from the degree of change in movement from the current operating point 7 to the pressure value of the operating point during normal operation plus the final pressure loss.

  The detection and prediction described above are handled by processing (execution) as software by monitoring by a control circuit (controller) included in the FFU or a monitoring system for monitoring the operation status of the FFU.

  In addition, various methods can be adopted as a method for notifying the detected abnormal state. For example, using several indicator lamps or display devices (for example, display displays) provided for each FFU, There is a method of informing through a display mode in which abnormal states are distinguished. In addition, using a monitoring system that manages the current FFU wind speed (air volume), pressure-related set values, detected values, etc., and manages them, the abnormal status is displayed as anomaly notification information. There is a method of making a notification according to a mode or a pronunciation mode.

1 Fan 2 Chamber 3 Pressure gauge 4 Tachometer 5 Filter 6 Anemometer

Claims (8)

With fans,
A chamber surrounding the fan from above;
A filter provided at the fan outlet;
A pressure gauge for detecting the pressure in the chamber;
Using a fan filter unit including a tachometer that detects the rotation speed of the fan,
A first operating point obtained from the static pressure-wind speed characteristic and the pressure value detected by the pressure gauge with respect to the static pressure-wind speed characteristic of the fan filter unit at the rotation speed of the fan detected by the tachometer. By comparing the static pressure-wind speed characteristic and the second operating point during normal operation obtained from the initial pressure characteristic of the filter, it is determined whether the filter is broken or clogged. An air purifier comprising one or more fan filter units, wherein an abnormal state of the fan filter unit is detected . The air purifier according to claim 1,
It said filter and an abnormal state is determined to be corrupted is when the pressure value of the first operating point is lowered below a predetermined degree than the pressure value of the second operating point <br/> An air purifier characterized by that. The air purifier according to claim 1,
Said filter abnormal state is determined to be clogged is when the pressure value of the first operating point is increased to a certain degree or more than the pressure value of the second operating point <br / > Air purifier characterized by that. With fans,
A chamber surrounding the fan from above;
A filter provided at the fan outlet;
An anemometer for detecting the wind speed of the fan filter unit;
Using a fan filter unit including a tachometer that detects the rotation speed of the fan,
A first operating point obtained from the static pressure-wind speed characteristic and the wind speed value detected by the anemometer with respect to the static pressure-wind speed characteristic of the fan filter unit at the rotation speed of the fan detected by the tachometer. By comparing the static pressure-wind speed characteristic and the second operating point during normal operation obtained from the initial pressure characteristic of the filter, it is determined whether the filter is broken or clogged. An air purifier comprising one or more fan filter units, wherein an abnormal state of the fan filter unit is detected . The air cleaning device according to claim 4,
It said filter an abnormal state to determine that is corrupted is when the wind speed value of the first operating point is increased to a certain degree or higher than the wind speed value of the second operating point <br/> An air purifier characterized by that. The air cleaning device according to claim 4,
It said filter abnormal state is determined to be clogged is when the wind speed value of the first operating point is lowered below a predetermined degree than the wind speed of the second operating point <br / > Air purifier characterized by that. The air purifier according to claim 1 or 4, wherein
The pressure values of the first operating point, before Kisei pressure - from wind characteristics on the variation degree of movement towards the second of the closing pressure loss added value of the filter to the pressure value of the operating point, the An air purifier characterized by predicting a remaining time until the lifetime of the filter. The air purification device according to any one of claims 1 to 7,
The fan display provided on the filter unit means or using said monitoring system which manages the operating state of the fan filter unit, before air cleaning apparatus characterized by notifying to distinguish dangerous out abnormal state.

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