JPH09229442A - Air flow controller for clean room - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air flow control device in which a variation in a degree of cleanliness caused by an external variation is easily restricted and a high reliability in operation can be attained. SOLUTION: When a direction of air stream detected by an air direction sensor SD arranged at an interface between adjoining area A and area B of a clean room is in a direction (B → A) which is opposite to a predetermined direction (A → B), an amount of clean air supplied from a blower 1 arranged at an area (area A) located at a downstream side is increased and a direction of air stream is controlled to the setting direction (A → B). In addition, as the air direction is corrected from its set direction in an opposite direction, the increased amount of clean air is reduced and then the amount of air is returned back to its original state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling an air flow in a so-called clean room in which dust particles and other contaminants in the air have been carefully removed in, for example, the semiconductor field, medical field, food manufacturing field and the like. .

[0002]

2. Description of the Related Art An air flow control device for a clean room supplies a quantity of clean air corresponding to each area of the clean room so that each area has a different degree of cleanliness. By keeping the amount constant for each area, that is, keeping the initial setting value, different cleanliness is ensured for each area. However, the cleanliness of each area easily changes due to people and things moving in and out of the clean room, so just keeping the amount of clean air supply constant will prevent dust particles and other contaminants from entering. That's not enough.

Therefore, the differential pressure between regions having different cleanliness is detected, and the supply amount of clean air in each region is increased or decreased so as to keep the differential pressure constant. There is known automatic control that suppresses fluctuations in cleanliness caused by.

[0004]

However, the pressure difference between the regions is often very small, such as several mmb, and the stability is poor, so the pressure difference must be set in advance. Also, for example, when the cleanliness of adjacent areas decreases (or increases) at the same time and the pressure difference does not change much, the amount of clean air supplied changes even if dust particles or other contaminants enter. There is also a defect that it does not exist. Further, it is complicated and difficult to sequentially set and control the differential pressure when a large number of regions are adjacent to each other.

Therefore, an object of the present invention is to provide a highly reliable airflow control device for a clean room, in which fluctuations in cleanliness due to external fluctuations are easily suppressed.

[0006]

In order to achieve the above object, the airflow control device for a clean room according to the present invention is provided for each area (A area, B area) of the clean room,
Blower (1, 2) that supplies clean air to the corresponding area
And a driver (3) for driving the blower (1, 2),
Areas adjacent to each other in the clean room (areas A and B) or areas adjacent to each other inside and outside the clean room (area B,
Wind direction sensor (SD, SE) that detects the wind direction of the boundary in (C area), wind speed sensor (SA, SB) that detects the wind speed of each area (A area, B area), and wind speed sensor (SA, SB) When the wind speed detected by) is within a predetermined permissible range, a control device (5) for controlling the supply amount of the clean air of the blower devices (1, 2) via the driver (3) is provided and controlled. In the device (5), the wind direction of the airflow detected by the wind direction sensors (SD, SE) is opposite to the preset direction (A → B, B → C) (B → A, C →).
In the case of B), the amount of clean air supplied from the air blowers (1, 2) provided in the regions located on the downstream side (A region, B region) is increased to set the wind direction of the airflow in the set direction (A → B,
B → C) (Claim 1).

Further, the control device (5) increases the blower device (1, 1 when the wind direction is corrected from the opposite direction (B → A, C → B) to the set direction (A → B, B → C). It is characterized in that the amount of clean air in 2) is reduced and returned to the original state (claim 2).

Symbols in parentheses indicate corresponding elements or matters in the description of the embodiments of the invention, which will be described later with reference to the drawings.

According to the first aspect of the invention, the direction of the clean air flowing at the boundary of the area is temporarily reversed due to external fluctuations such as an operator entering the area inside the clean room from the area outside the clean room. Even if it is turned on, the air volume of the downstream blower is automatically increased, so that the clean air again flows in the original positive direction. Thereby, the cleanliness can be automatically controlled so that the cleanliness is always higher in the order of the preset areas. Since such control of the degree of cleanliness is controlled not by the pressure difference between the conventional areas but by the wind direction and speed, the control is easy and highly reliable.

Further, according to the second aspect of the invention, when the external fluctuation disappears, the increased air volume of the air blower is returned to the original state, so that there is no danger of the air volume increasing infinitely and there is no danger of each area increasing. The cleanliness level in can be always kept constant.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 shows an area A (area having a semiconductor wafer assembling apparatus) and an area B (area having a manual workbench) in an air flow control device of a clean room according to a first embodiment of the present invention. FIG. 2 is a block diagram showing a state in which it is applied to a clean room consisting of FIG. 2, and FIG. 2 is a block diagram showing a schematic configuration of a control system of an airflow control device of the clean room according to the first embodiment of the present invention.

As shown in FIGS. 1 and 2, the airflow control device of this clean room is provided with a blower 1 for supplying clean air to the area A and a clean air for the clean air in the area B as well. Blower 2 to supply, and blowers 1 and 2
A driver 3 having an inverter circuit for driving a wind direction sensor SD, a wind direction sensor SD for detecting the wind direction at the boundary between the adjacent areas A and B, a wind direction sensor SE for detecting the wind direction at the boundary between the area B and the area C outside the clean room, A wind speed sensor SA that detects the wind speed in the A area, a wind speed sensor SB that detects the wind speed in the B area, and the amount of clean air supplied to the blowers 1 and 2 via the driver 3 based on the input from each sensor. And a control unit 5 for controlling the operation.

The wind direction sensor SD and the wind direction sensor SE are
At the same time, the wind speed at the boundary of the area can be measured. The sensors SA, SB, SD and SE are of the hot wire Tr system. Alternatively, an ultrasonic type or a heat ray resistance type may be used. The control unit 5 is composed of a CPU that controls the entire operation, and is connected to a storage unit 4 such as a RAM or a ROM and an operation display unit 6 that can set the supply amount of clean air and the like. Power is supplied from the power supply unit 7 to these electric elements.

The clean air supplied from the blowers 1 and 2 passes through the HEPA filters 8 and 9 on the ceiling, and is in the areas A and B.
Supplied to the area. After that, the supplied clean air passes through the exhaust duct under the floor and returns to the blowers 1 and 2.

Next, the processing contents of the control unit 5 will be described with reference to FIGS. The control unit 5 initializes when the power is turned on (step 1; “the word step is omitted in parentheses” hereinafter). At initialization, internal timers, counters, etc. are set to initial values. Then, the control unit 5 sets a flag F indicating whether or not the wind direction preset by the wind direction sensors SD and SE has been reversed to 0, and 0.3 in the register VA that determines the air volume of the blower 1.
(M / s) is set, and 0.2 (m / s) is set in the register VB that determines the air volume of the blower 2 (2). The numerical values set in the registers VA and VB are input in advance via the operation display unit 6 and can be changed. As a result, in the clean room of the present embodiment, the air volume in the A area is set to be larger than the air volume in the B area, so that the wind direction at the boundary between the A area and the B area is normally from A to B (A → B). Further, the wind direction at the boundary between the B area and the C area is from B to C (B → C). That is, the cleanliness is set to increase in the order of C area, B area, and A area.

Next, the control unit 5 controls the set register VA.
And the blower 1 and the blower 2 corresponding to the value of the register VB
Determine the amount of airflow and blow it (3). In this embodiment,
At normal times, the air volume from the blower 1 is 0.3 (m / s) at the detection position of the wind speed sensor SA, and the air volume from the blower 2 is 0.2 (m / s) at the detection position of the wind speed sensor SB. Controlled. Next, the control unit 5 reads the wind speed / wind direction (4). Then, the wind speed values detected by the wind speed sensors SA and SB are stored in the registers VSA and VSB, respectively.
The wind direction detected by the wind direction sensors SD and SE is registered in the register DS
Store in D and DSE respectively.

Next, the control unit 5 controls the registers VSA and VSB.
Check whether both values are within the predetermined allowable range (5). If they are not within the allowable range, the blowers 1 and 2 may be overheated. Stop (6). If it is within the allowable range, the wind direction of the register DSE changes from the B area to the C area (B →
It is checked whether it is C) (7). If the wind direction is B → C as originally set, the register DSD is also used.
It is checked whether the wind direction of A is from A region to B region (A → B) (8), but if the wind direction of the register DSE is C → B which is the opposite direction to the initial setting, 1 is set to the flag F. Then, (9), the air flow to the area B located on the downstream side is increased (10). That is, the value of the register VB is increased by a predetermined value XB and the process returns to step 3 to increase the air volume of the blower 2. This is repeated until the wind direction of the register DSE changes from B to C. Further, in step 8, if the wind direction of the register DSD is B → A, which is the opposite direction to the original setting, the flag F is set to 1 (11), and the air blowing to the area A located on the downstream side is increased (12). ). That is, the value of the register VA is increased by a predetermined value XA and the process returns to step 3 to increase the air volume of the blower 1. The wind direction of register DSD is A
→ Repeat until it becomes B.

In step 7 and step 8 the register DS
Wind direction of E is B → C, and wind direction of register DSD is A → B.
If so, it is checked whether the flag F is set to 1, that is, whether the wind direction has already been corrected (13). If the flag F is 0, the process returns to step 3, but if the flag F is 1, the process of returning the blower whose air volume has been increased by the process of step 10 and / or step 12 to the original state is performed. First, it is checked whether the value of the register VB is equal to or less than 0.2 (m / s) of the initial setting (14), and if it is equal to or less than 0.2 (m / s), the blower 2 is in the original state. Then, it is determined whether the value of the register VA is equal to or less than 0.3 (m / s) which is the initial setting (15). If it is 0.3 (m / s) or less, it is determined that the blower 1 is in the original state, and the flag F is set to 0 (1
6) Return to step 3.

In step 14, the value of register VB is 0.2.
If it is larger than (m / s), the air blow to the B area is reduced (17). That is, the value of the register VB is decreased by a predetermined value XB and the process returns to step 3 to decrease the air volume of the blower 2. This is repeated until the value of the register VB becomes 0.2 (m / s) or less. Further, when the value of the register VA is larger than 0.3 (m / s) in step 15, air blowing to the area A is reduced (18). That is, register V
The value of A is decreased by a predetermined value XA and the process returns to step 3 to decrease the air volume of the blower 1. This is repeated until the value of the register VA becomes 0.3 (m / s) or less.

By the processing of the control unit 5 as described above, normally, due to an external variation such as an operator coming from the area C outside the clean room to the area B inside the clean room as shown in FIG. Even if the direction of the clean air flowing in the C area is temporarily reversed, the air volume in the B area is automatically increased, so that the clean air flows from the B area to the C area. Further, at this time, even if the direction of the clean air flowing from the A area to the B area is temporarily reversed, the air volume in the A area is automatically increased, so that the clean air flows from the A area to the B area. . As a result, the cleanliness is always set to be higher in the order of C area, B area, and A area (C <B <A) automatically. When the external fluctuation disappears, the increased air volume is returned to the original state, so that the cleanliness in the C area, B area, and A area is always kept constant.

(Second Embodiment) FIG. 5 is a block diagram showing a state in which an air flow control device for a clean room according to a second embodiment of the present invention is applied to a clean room including an F region and a G region. The wind direction sensor SH is provided at the boundary between the adjacent F and G regions, and the wind speed sensors SF and G are provided at the F region.
Wind speed sensors SG are provided in the respective regions.
Note that the outline of the configuration of the control system is the same as that shown in FIG. 2 shown in the first embodiment, and therefore its explanation is omitted.

Next, referring to FIG. 6, the processing contents of the control unit 5 according to the second embodiment will be shown. When the power is turned on, the control unit 5 initializes similarly to the first embodiment (21), and sets the flag F indicating whether or not the wind direction preset by the wind direction sensor SH is reversed to 0. With setting
The register VF that determines the air volume of the blower 1 is set to 0.3 (m /
s) is set and 0.2 (m / s) is set in the register VG that determines the air volume of the blower 2 (22). As a result, in the clean room of the present embodiment, the air volume in the F area is set to be larger than the air volume in the G area, so that the wind direction at the boundary between the F area and the G area is normally in the direction from F to G (F → G). It has become. Next, the control unit 5 determines the air volumes of the blower 1 and the blower 2 in accordance with the set values of the register VF and the register VG and blows them (23).
In this embodiment, normally, the air volume from the blower 1 is 0.3 (m / s) at the detection position of the wind speed sensor SF, and the air volume from the blower 2 is 0.2 (m / s) at the detection position of the wind speed sensor SG.
s) is controlled. Next, the control unit 5 controls the wind speed
The wind direction is read (24). Then, the wind speed values detected by the wind speed sensors SF and SG are stored in the registers VSF and VSG.
The wind direction detected by the wind direction sensor SH is stored in the register DSH.

Next, the control unit 5 controls the registers VSF and VSG.
It is checked whether both of the values are within a predetermined allowable range (25), and if they are not within the allowable range, the entire system is stopped (26). If it is within the allowable range, it is checked whether or not the wind direction of the register DSH is from the F region to the G region (F → G) (27), but the wind direction of the register DSH is opposite to the initial setting G → F. If so, the flag F is set to 1 (28), and the air flow to the F region located on the downstream side is increased (29). That is, the value of the register VF is increased by a predetermined value XF and the process returns to step 23 to increase the air volume of the blower 1. This is repeated until the wind direction of the register DSH changes from F to G. If the wind direction of the register DSH is F → G in step 27, it is checked whether or not the flag F is set to 1, that is, whether or not the wind direction has already been corrected (30), and the flag F is set. If it is 0, the process returns to step 23, but if it is 1, the process of returning the blower 1 whose air volume has been increased by the process of step 29 to the original state is performed. That is, the value of the register VF is set to 0.3 of the initial setting.
It is checked whether or not (m / s) or less (31).
If it is 0.3 (m / s) or less, the blower 1 determines that it is in the original state, sets 0 in the flag F (32), and returns to step 23.

In step 31, the value of the register VF is 0.3.
If it is larger than (m / s), the air blowing to the F region is reduced (33). That is, the value of the register VF is decreased by a predetermined value XF and the process returns to step 23 to decrease the air volume of the blower 1. This is repeated until the value of the register VF becomes 0.3 (m / s) or less.

By the processing of the control unit 5 as described above, even if the direction of the clean air normally flowing from the F region to the G region is temporarily reversed due to the external fluctuation, the air volume in the F region is automatically increased. Therefore, clean air flows from the F region to the G region. As a result, the cleanliness is always set higher in the order of G area and F area (G <F) automatically. When the external fluctuation disappears, the increased air volume is returned to the original state, so that the cleanliness in the G region and the F region is always kept constant. In the present embodiment, the air volume of the blower 1 on the F region side is increased in order to make the reverse direction of the clean air from the F region to the positive direction of the G region, but at the same time, the air volume of the blower 2 on the G region side is increased. May be controlled so as to go down, and may be returned to the original state after correction.

[0026]

As described above, according to the first aspect of the present invention, the cleanliness can be automatically controlled so that the cleanliness becomes higher in the order of the preset areas. The control is easy and highly reliable because it is controlled by the wind direction and speed rather than by the minute pressure difference between the areas.

Further, according to the second aspect of the present invention, when the external fluctuation disappears, the increased air volume of the air blower is returned to the original state, so that there is no danger of the air volume increasing infinitely and there is no danger of each area increasing. The cleanliness level in can be always kept constant.

[Brief description of drawings]

FIG. 1 is a block diagram showing a state in which an airflow control device for a clean room according to a first embodiment of the present invention is applied to a clean room including an area A and an area B.

FIG. 2 is a block diagram showing a schematic configuration of a control system of an airflow control device for a clean room according to the first embodiment.

FIG. 3 is a flowchart showing processing contents of a control unit 5 according to the first embodiment.

FIG. 4 is a flowchart showing processing contents of a control unit 5 according to the first embodiment.

FIG. 5 is a block diagram showing a state in which an airflow control device for a clean room according to a second embodiment of the present invention is applied to a clean room including an F region and a G region.

FIG. 6 is a flowchart showing processing contents of a control unit 5 according to the second embodiment.

[Explanation of symbols]

 1, 2 Blower 3 Driver 4 Storage section 5 Control section 6 Operation display section 7 Power supply section 8, 9 HEPA filter SA, SB Wind speed sensor SD, SE Wind direction sensor SF, SG Wind speed sensor SH Wind direction sensor

Claims (2)

[Claims] 1. A blower device provided in each region of a clean room for supplying clean air to a corresponding region, a driver for driving the blower device, an adjacent region in the clean room or a region adjacent to the inside and outside of the clean room. At the boundary, the wind direction sensor for detecting the wind direction, the wind speed sensor for detecting the wind speed of each area, and the wind speed detected by the wind speed sensor within a predetermined allowable range, the driver of the air blower via the driver. A control device for controlling the supply amount of clean air, wherein the control device is arranged in a region located on the downstream side when the wind direction of the air flow detected by the wind direction sensor is opposite to a preset direction. Airflow control in a clean room, characterized in that the amount of clean air supplied from an air blower provided is increased to set the airflow direction of the airflow to a set direction. Location. 2. The airflow control of a clean room, wherein the control device reduces the increased clean air amount of the air blowing and returning to the original state when the wind direction is corrected from the opposite direction to the set direction. apparatus.