JPH0778463B2 - Air filter dust measuring instrument - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dust measuring device for measuring the amount of dust due to air leakage in an air filtering device provided in a clean room or the like.

(Prior Art) In recent years, in various fields such as precision industry for manufacturing semiconductors, biotechnology, or pharmaceutical industry, a high degree of clean space is required. The air is being cleaned.

For example, as shown in FIG. 3, (1) is a working chamber for cleaning, and a side wall (2) has a rectangular air supply chamber (3) and an exhaust chamber (4) whose front faces are indoors. It is installed by opening. An ultra-high performance filter (HEPA filter) (5, 6) is provided in the interior opening of each chamber (3, 4).
Is provided, and an air supply port (7) and an exhaust port (8) are opened on the side surface. An air supply duct (10) equipped with an air supply fan (9) is provided at the air supply port (7) of the intake chamber (3), and suction means is provided at the exhaust port (8) of the exhaust chamber (4). The exhaust ducts (12) each having the exhaust fan (11) are connected in series.

Therefore, outside air is sucked by the air supply fan (9), filtered through the filter (5) and then sent into the room, while contaminated air in the room is sucked by the exhaust fan (11) and filtered through the filter (6). After that, it is discharged outdoors.

The attachment structure of each chamber (3, 4) and filter (5, 6) in this air filter device is formed as a dust leakage prevention structure. Explaining this attachment structure on the exhaust side shown in FIG. The front end of the chamber (4) is bent and formed into a substantially L shape, and the front end and the side wall (2) of the working chamber (1) are formed.
Silicon caulking (13) is applied between and to keep airtight. In addition, the fixed seat (14) of the filter (6) is fixed in the exhaust chamber (4) by protruding inward, while the filter (6) is a filter media (6a).
A frame (6b) is formed around the circumference of.

Then, the frame body (6b) of the filter (6) is clamped by the tightening metal fitting (16) between the fixing seat (14) and the supporting metal fitting (15), and at the same time, the frame body (6b) and the fixing seat (14). ) And a gasket (17) are interposed between them and are kept airtight. This prevents the leakage of dust. Reference numeral (18) is a decorative plate such as a punching plate, which covers the indoor side opening of the exhaust chamber (4).

In this air filtering device, the dust is prevented from leaking as described above, but scratches and mounting defects (such as poor tightening and gasket (1
Air leakage may occur due to (7) Non-uniform contact surface. This air leak cannot be visually confirmed, and if it is used as it is, for example, in a biohazard control facility, pathogenic bacteria and the like are released into the air, which causes a serious human injury accident.

Therefore, an air leak test, that is, dust measurement is performed when the filters (5, 6) are attached or regularly. This dust measurement includes a scanning test and a total efficiency test. This scanning test is performed in the magazine "Air Purification", Vol. 24, No. 2 (published by the Japan Air Purification Association), page 16, 5.5.5- (7). ) Is disclosed.

That is, as shown in FIG. 3, a DOP generator (dioctyl phthalate generator) (20) according to JIS-Z-8901 is installed at the air supply end of the air supply duct (10) and contains DOP. Inhale contaminated air. Then, the front surface of the filter (5) is scanned by the sampling hose (21) to measure the dust amount,
Presence of air leak is detected.

However, this scanning test is possible on the air supply side as described above, but it is not possible on the exhaust side because the inside of the exhaust chamber (4) is airtight. Therefore, on this exhaust side, as shown in FIG. 4, a sampling hole (a) is bored in the bottom surface of the exhaust chamber (4) and the exhaust duct (12) to perform a comprehensive efficiency test. That is,
DOP in front of the exhaust chamber (4) in the working room (1)
The generator (20) is installed, the contaminated air is sucked in as in the scanning test, and the exhaust air that has passed through the filter (6) is sampled from the inside of the exhaust chamber (4) through the sampling hole (a) to measure the amount of dust. Is measured to detect the presence or absence of air leaks.

(Problems to be Solved by the Invention) However, as shown in FIG. 5, the above-described air leak phenomenon causes air leak A from the pinhole H of the filter media (6a).
In addition to the above, there is a possibility that air leakage B may occur around the gasket (17) due to improper mounting.
The air leak A was extremely fine, and there was a problem that the air leak A could not be detected by sampling from the sampling hole (a) as described above.

That is, since the air leakage A is minute, the exhaust air is in a substantially linear flow state on the downstream side of the filter (6), dust flows along the flow to the exhaust duct (12), and at the bottom surface of the exhaust chamber (4). Dust could not be satisfactorily measured from the sampling hole (a), and the test results were unreliable.

Therefore, in order to perform a highly reliable measurement, it is conceivable to provide a considerable approach distance to the sampling hole (a) or to disturb the air in the exhaust chamber (4). However, the former one has a problem that it is difficult to distinguish it from the background such as air leak from the exhaust duct (12). Further, the latter one has a drawback that the pressure loss becomes large, and it is difficult to adopt any of them.

Furthermore, in the sampling using only the sampling hole (a), there are air leaks from the pinhole H and the gasket (17) as described above. There was a problem that could not be determined. Therefore, in the case of air leak A in the pinhole H, the filter (6) needs to be replaced, but in the case of air leak B in the gasket (17), only the retightening of the fastening metal fitting (16) and the gasket (17) are necessary. Although it can be prevented by replacing the filter, there is a problem that the filter (6) is erroneously dealt with.

In view of such a point, the present invention focuses on the point that the exhaust air in the exhaust chamber contracts toward the exhaust port, and the exhaust air is sampled in front of the exhaust port to accurately detect the leak air. An object of the present invention is to enable detection and also to determine the leak content by sampling the exhaust air at the outer peripheral edge inside the filter chamber.

(Means for Solving the Problems) In order to achieve the above-mentioned object, means taken by the present invention are as follows.
As shown in FIG. 1, an exhaust chamber (4) is provided with a filter (6) for filtering air, an exhaust port (8) is opened, and the exhaust port (8) is provided with suction means (11). It is premised on an air filtering device in which an exhaust duct (12) is connected.

A sampling cylinder (32) made of a hollow body is provided in the exhaust chamber (4) in the state of being close to the exhaust port (8) and longitudinally crossing the exhaust port (8). Further, the sampling cylinder (32) has a sampling hole (34) formed on the side surface on the air upstream side. Further, one end of the sampling cylinder (32) is closed and the other end is connected to an extension pipe (33) led out into the room.

On the other hand, a sampling ring (42) formed by annularly forming a hollow body in the exhaust chamber (4) is provided close to the outer peripheral edge of the filter (6) inside the chamber (4). Further, a sampling hole (44) is formed on the inner peripheral surface of the sampling ring (42). In addition, an extension pipe (43) led out into the room is connected to the sampling ring (42).

Exhaust air passing through the outlet (8) from the sampling tube (32) and the sampling ring (42).
Further, the exhaust air in the outer peripheral edge portion inside the chamber (4) of the filter (6) is sampled.

(Operation) With the above configuration, in the present invention, the filter (6)
The exhaust air flowing through the discharge port (8) in a linear flow state and contracted at the discharge port (8) is sampled by the sampling cylinder (32). Then, the amount of dust is measured from this sampling air to detect leakage.

Therefore, the air leaked from the filter (6) flows toward the discharge port (6) together with the discharge air, so that the sampling cylinder (32)
The leak can be detected reliably, and highly reliable detection can be performed.

Further, since the exhaust air at the peripheral portion of the filter (6) is sampled by the sampling ring (42) and the amount of dust is measured, only the air leak at the peripheral portion of the filter (6) can be detected separately.

Therefore, the sampling tube (32) and the sampling ring (42)
Since the cause of air leakage can be determined by and, it is possible to accurately replace the filter (6) or the like according to the cause of air leakage.

(Example) Hereinafter, the Example of this invention is described in detail based on drawing. In addition, since the air filtering device provided in the various working chambers (1) has already been described (see FIGS. 3 and 4),
Detailed description thereof will be omitted.

As shown in FIG. 1, (31) is the first dust detection means for sampling the exhaust air passing through the exhaust port (8), and (41) is the inner peripheral edge of the ultra high performance filter (HEPA filter) (6). Is a second dust detecting means for sampling the exhaust air of the.

As shown in the enlarged view of FIG. 2, the first detecting means (31) is formed by connecting an extension pipe (33) to the lower end of a sampling cylinder (32), and the sampling cylinder (32) is a straight cylinder. It is formed of a hollow body. Furthermore, the upper end surface of the sampling cylinder (32) is closed, and in the exhaust chamber (4), in front of the exhaust port (8) (air upstream side).
The exhaust port (8) is provided so as to be close to it, and the exhaust port (8) is provided in such a manner that a substantially central portion thereof is vertically cut vertically.

The sampling cylinder (32) is formed to be slightly shorter than the vertical length of the exhaust port (8) because the exhaust air contracts at the exhaust port (8). (4 in the drawing) circular sampling holes (34) are provided in parallel in the vertical direction, and a part of the exhaust air passing through the exhaust port (8) is introduced into the sampling tube (32) from the sampling hole (34). Is configured to flow into.

The extension pipe (33) communicates with the inside of the sampling tube (32) at the upper end, and the lower end has the filter (6).
Is located at the front opening of the exhaust chamber (4) and is led out into the working chamber (1). The inner end of the extension pipe (33) serves as a connecting end (35) of the measuring device main body (not shown) and is normally closed with a plug.

On the other hand, the second detecting means (41) includes a sampling ring (4
An extension pipe (43) is connected to 2), and the sampling ring (42) also serves as the fixed seat (14) of the filter (6) shown in FIG. The sampling ring (42) has a horizontally long rectangular hollow body formed in an annular shape along the inner surface of the exhaust chamber (4), and an outer peripheral surface thereof is airtightly fixed to the inner surface of the exhaust chamber (4). The inner peripheral surface is located at the inner peripheral edge of the filter frame (6b).

A filter (6) is provided on the sampling ring (42).
Are airtightly connected by a frame (6b) via a gasket (17), and the sampling ring (42) is provided close to the outer peripheral edge of the filter (6) inside the chamber (4). Further, a plurality of sampling holes (44) are formed in a circular shape on the inner peripheral surface of the sampling ring (42) so that the exhaust air in the peripheral portion inside the chamber (4) of the filter (6) is discharged. It is configured to flow into the sampling ring (42) through the sampling hole (44).

Further, the extension pipe (43) communicates with the inside of the sampling ring (42) at an upper end, and the lower end has a filter (6).
Is located at the front opening of the exhaust chamber (4) and is led out into the working chamber (1). As with the first detecting means (31), the indoor end of the extension pipe (43) serves as the connecting end (45) of the measuring device main body (not shown), and is normally closed with a plug.

The extension pipe (33) of the first detecting means (31) is the second pipe.
The sampling ring (42) of the detection means (41) is extended to extend through the sampling ring (42) and the extension pipe (3).
An airtight treatment is made between 3) and a sealing material (36) such as silicon caulking. Furthermore, the sampling ring (42)
The sealing material (46) is also hermetically sealed between the extension pipe (43) and the extension pipe (43).

Further, the filter (6) is attached to the sampling ring (42) by the support fitting (15) and the fastening fitting (16) as in FIG. 4, and the front surface of the exhaust chamber (4) is a decorative plate (1).
8) covered with.

Next, a dust measurement operation in the exhaust chamber (4) will be described.

First, as in the conventional dust measurement, as shown in FIG.
A DOP generator (20) is installed in front of the exhaust chamber (6) so that polluted air containing DOP is sucked into the exhaust chamber (6). And polluted air is a super high performance filter (6)
Will be filtered through. At that time, as shown in FIG. 5, if there is a pinhole H in the filter medium (6a), air leakage A will be generated and dust will be discharged. If the contact surface of (17) is not uniform, air leak B will be generated from the outer peripheral edge of the filter (6) and dust will be discharged.

Therefore, a measuring device body (not shown) is connected to the extension pipes (33) and (43) of the first and second detecting means (31) and (41) to sample the exhaust air in the exhaust chamber (6). After passing through the filter (6), this exhaust air flows toward the exhaust port (8) in a substantially linear flow state, and the exhaust port (8)
In the vicinity, the flow is contracted and flows into the exhaust duct (12). Then, the dust generated by the air leaks A and B flows together with the exhaust air, and a part of the exhaust air containing the dust flows from the sampling hole (34) in front of the exhaust port (8) to the sampling tube (3).
Inflow into 2). The discharged air is guided to the measuring instrument body through the extension pipe (33) to detect the dust amount. By this detection, air leaks A and B will be detected.

Further, the air discharged from the peripheral portion of the filter (6) also enters the sampling hole (4) in the sampling ring (42) of the second detecting means (41).
4) will flow in through. Then, the discharged air is guided to the measuring device main body through the extension pipe (43), the amount of dust is detected, and the air leak B at the peripheral portion of the filter (6) is detected.

Therefore, even the minute air leak A generated from the pinhole H of the filter (6) flows toward the exhaust port (8) in a linear flow state and is contracted, so that the sampling cylinder (31) causes the air leak A to flow. Is reliably detected, and highly reliable measurement can be performed.

Further, since the leak B at the peripheral portion of the filter (6) is detected separately by the sampling ring (42) of the second detecting means (41), the leak A of the filter (6) itself or the gasket (17) is used. Since it is possible to determine whether the air leak is B, unnecessary filter (6) replacement can be prevented.

Although the sampling cylinder (32) is a cylinder in the above embodiment, it may be a rectangular cylinder or the like, and the sampling ring (42) may be a cylinder or the like in addition to the rectangular cylinder, and the fixed seat ( It is not necessary to combine 17).

Further, the sampling holes (34, 44) may be one slit or the like.

(Effect of the Invention) As described above, according to the dust measuring instrument of the air filtering device of the present invention, since the sampling cylinder is provided in the vicinity of the exhaust port and the exhaust air passing through the exhaust port is sampled, Since the exhaust air contracted in the linear flow state is sampled, leak air is sampled reliably, and highly reliable measurement can be performed, and the filter can be replaced accurately.

Further, since the dust can be measured from the room with the filter attached, the measurement can be easily performed.

In addition, since the sampling ring also samples the exhaust air at the outer peripheral edge of the filter inside the chamber to measure the amount of dust, the air leakage at the peripheral edge of the filter, that is, the air leakage due to improper mounting of the filter, etc. is separately provided. Can be detected. Therefore, it is possible to determine whether the air is leaking from the filter itself such as a pinhole or the air that is not properly attached to the filter by the sampling cylinder and the sampling ring. Therefore, it is possible to accurately replace the filter or the like depending on the cause of air leakage, and to prevent useless filter replacement in the event of air leakage due to poor mounting.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention. FIG. 1 is a vertical sectional view showing the inside of an exhaust chamber, and FIG. 2 is a perspective view of a sampling cylinder. FIG. 3 is a schematic view of an air filtration device. FIG. 4 is a vertical cross-sectional view showing the inside of a conventional exhaust chamber, and FIG. 5 is a vertical cross-sectional view omitting the same portion showing the air leakage phenomenon. (1) ... Work room, (3) ... Air supply chamber, (4) ...
... Exhaust chamber, (5), (6) ... Filter, (8)
...... Exhaust port, (11) …… Exhaust fan, (12) …… Exhaust duct, (17) …… Gasket, (31) …… First detection means, (32) …… Sampling tube, (33)… … Extension pipe, (34) …… sampling hole, (41) …… second detection means, (42) …… sampling ring, (43) …… extension pipe, (44) …… sampling hole.

Claims (1)

[Claims] 1. An exhaust chamber (4) whose front surface is open to the inside of the room.
A filter (6) whose peripheral portion is airtightly connected to the exhaust chamber (4) and attached to an indoor opening of the chamber (4); and an exhaust duct (12) formed in the exhaust chamber (4). And an exhaust port (8) connected to each other and a suction means (11) provided in the exhaust duct (12) for sucking indoor air
In the air filtering device, which comprises: (1) filtering indoor air through the filter (6) and discharging it through the exhaust duct (12), a sampling tube ( 32) is provided in a state of being close to the exhaust port (8) and longitudinally crossing the exhaust port (8), and the sampling cylinder (32) is provided with a sampling hole (34) on the side surface on the air upstream side. At the same time, one end of the sampling hole (32) is closed and the other end is an extension pipe (33) led out into the room.
And a sampling ring (4) formed by annularly forming a hollow body at the indoor opening of the exhaust chamber (4).
2) is provided close to the outer peripheral edge of the inside of the chamber (4) of the filter (6), a sampling hole (44) is formed in the inner peripheral surface of the sampling ring (42), and the sampling ring An extension pipe (43) led out into the room is connected to (42), and exhaust air passing through the outlet (8) from the sampling cylinder (32) and the filter (6) from the sampling ring (42). The exhaust air in the outer peripheral edge inside the chamber (4) is sampled respectively, and the dust measuring instrument of the air filtering device is characterized.