JPH0576781A - Clean draft chamber - Google Patents

Abstract

PURPOSE:To discharge the contaminated air which has been generated in operation and accumulated in a recess and to secure a clean and large working space with a low power cost by forming the recess for setting a chemical container in the working bench set in the working space in a chamber. CONSTITUTION:A blower 5 provided with an air filter 4 is set on the ceiling of a clean draft chamber 1, and the clean air is supplied to a working space 3. An exhaust port 12 is formed in a working bench 6, and the contaminated air is forcedly discharged by an exhauster 7. An air suction port 11 is formed in the bench 6 along the edge of its opening 8 and used as the air inlet of the blower 5. A recess 10 is formed in the bench 6 to set a chemical container 13. The exhaust port 12 is provided between the side wall 14 of the recess 10 and the suction port 11 and communicated with the exhauster 7 through an exhaust duct 17. A cleaned air injection nozzle 19 is set on the ceiling to generate a high-speed air current to be introduced into the recess 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clean draft chamber which is used when performing a work requiring a dust-free environment while using a chemical solution that generates a harmful vapor or gas such as a volatile organic solvent or an acid. It is a thing.

[0002]

2. Description of the Related Art A clean draft chamber is used when it is necessary to perform a cleaning or etching operation using a volatile organic solvent or an acid in a dust-free environment in the manufacturing process of semiconductor products, precision machine parts and the like. A normal draft chamber equipped only with an exhaust device for discharging harmful gas takes in dusty air around the draft chamber from its working opening, but the clean draft chamber has a high ceiling as shown in FIG. Performance A blower 32 with an air filter 31 is installed to supply purified air to the work space 33 from the ceiling, and an exhaust port 35 is provided in or around the workbench 34 so that contaminated air is forcibly discharged by the exhaust device 36. Therefore, the working space 33 is kept in a clean environment with less suspended dust than the surroundings of the draft chamber.

When this clean draft chamber is used, in order to prevent the organic solvent and acid vapor contained in the container 37 from leaking out of the working opening 38 of the chamber, a high-performance air filter 31 is used. The amount of polluted air in the chamber Q ₃ exceeding the flow rate (m ³ / min) Q ₁ of the supplied clean air is discharged by the exhaust device 36, whereby an amount Q ₂ of ambient air equal to Q ₃ −Q ₁ is generated. Working opening 38
To always flow into the chamber at wind speed v.
However, the cleanliness in the chamber decreases as the inflow amount Q _{2 of the} surrounding air with a large amount of suspended dust decreases, so it is not preferable to increase the amount too much, and the wind speed v can be increased depending on the type of work performed in the chamber. As 0.25 m / se
It is limited to c or less, 0.4 m / sec or less, or 0.5 m / sec or less.

When the wind speed v is maintained at a predetermined value, the peripheral air inflow amount Q ₂ is proportional to the opening height H which is variable by the vertically moving shutter 39. The inflow amount Q ₂ increases. Therefore, when the height H of the opening is increased due to work requirements, a large amount of ambient air is taken into the draft chamber and discarded, which increases the air conditioning cost of the draft chamber installation room. Become. Further, in order to ensure the cleanliness in the chamber while taking in the ambient air, the clean air supply amount Q ₁ must be set to a high level, which results in a large amount of contaminated air Q _{3 in the} chamber and the blower 32. There is also a problem that the power cost of the exhaust device 36 is high. Therefore,
A device that generates clean jet air that flows down from the upper part of the work table to the work area across the work table periphery in order to reduce the amount of ambient air taken into the draft chamber and ensure the cleanliness of the chamber. However, when a highly volatile solvent is used, some areas cannot be covered by the above clean jet air.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in a clean draft chamber and to secure a clean and wide working space with a small amount of ambient air intake and a low power cost. To provide a draft chamber.

[0006]

[Means for Solving the Problems] A blower with a high-performance filter is installed on the ceiling so that clean air can be supplied to the work space from the ceiling, and an exhaust port is provided on or around the workbench to contaminate the air. In a clean draft chamber in which the air is forcibly discharged by an exhaust device, an intake port is provided along the edge of the opening on the workbench, and this is used as the air intake port of the blower, and the workbench is installed A recess is provided, and an exhaust port is provided between the side wall of the recess for installing the chemical liquid container and the recess for installing the chemical liquid container on the work table and the intake port, and these exhaust ports are communicated with an exhaust device by an exhaust duct. A cleaning air injection nozzle was installed in the ceiling part that generates a high-speed air flow that flows into the recess for installing the liquid medicine container across the portion where the recess for installing the liquid container is not installed.

[0007]

When the clean draft chamber of the present invention is used, the chemical solution container containing the organic solvent or acid necessary for the work is placed in the chemical solution container setting recess in principle. This allows
The contaminated air generated during the work stays mainly in the recess for installing the chemical liquid container without diffusing into the entire work space. This contaminated air enters the duct through the exhaust port on the side wall of the recess when the exhaust device is operated, and is discharged outdoors. On the other hand, when the blower for supplying clean air is operated, the relatively clean air inside the chamber near the chamber opening and the ambient air are sucked in through the intake port and filtered by the high-performance air filter to become clean air from the ceiling. Run down to the workbench. Since most of this clean air is sucked in through the intake port, most of the clean air will circulate in the above path.

When an air pollution source such as a chemical solution container is placed on a portion other than the recess for installing the chemical solution container on the workbench, most of the contaminated air generated on the workbench is jetted from the cleaning air jetting device. The high-speed airflow that is generated and flows into the concave portion flows into the concave portion, merges with the contaminated air generated in the concave portion, and is discharged to the outside by the exhaust device. Of the contaminated air generated on the workbench that did not flow into the recess,
Before flowing into the intake port, it is sucked into the exhaust port between the recess and the intake port, merges with the contaminated air from the recess exhaust port, and is discharged outdoors.

The amount of air injected from the cleaning air injection nozzle may be a negligible amount as compared with the amount of cleaning air circulated by the blower, so that the ambient air inflow amount and the inflow wind speed from the chamber opening are practically the same. , Determined only by the amount of air discharged from the exhaust port.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the implementation of the clean draft chamber 1 of the present invention will be described below with reference to the drawings.

The clean draft chamber 1 of the present invention is
A high-performance filter 4 and a blower 5 for sending clean air into the chamber 2 are installed on the ceiling of the work space 3 inside the chamber 2, and the air around the work table 6 below the work space 3 is installed outside the chamber 2. An exhaust device 7 for sucking in and discharging the air to the outside of the chamber 2 is installed, and a circulation duct 9 for guiding the air near the opening 8 of the work space 3 to the blower 5 provided on the ceiling portion is provided. Worktable 6 has two recesses 10 for installing the chemical solution container.
And has an intake port along the edge of the opening 8 side in front of the
11, and a slit-shaped exhaust port 12 is provided between the suction port 11 and the drug solution container installation recess 10.

The recess 10 for installing the liquid medicine container is deep enough to completely accommodate the liquid medicine container 13. The side wall 14 has an exhaust port 15 and the bottom plate 16 has a drain pipe (not shown) such as cleaning water. Is for connecting). The intake port 11 is formed by a gutter-shaped perforated plate, and communicates with the blower 5 on the ceiling by a duct 9 passing through the bottom of the chamber 2 and the back of the work space 3. Below the blower 5, there is a high-performance filter 4, and all the air sent out by the blower 5 passes through this high-performance filter 4 and flows down into the work space 3.

An exhaust duct 17 is provided around and below the recess 10 for installing the liquid container, and its end portion is provided with the intake port 11 and the recess 10 for installing the liquid container as described above along the edge of the opening 8. The exhaust port 12 of the chemical liquid container installation recess 10 is open to the exhaust port 12 provided between the two. The exhaust duct 17 communicates with the exhaust device 7. A nozzle 19 for injecting purified air is fixed to the ceiling of the chamber 2. The mounting posture is selected so that the central axis X of the nozzle 19 crosses the working space 3 above the portion on the workbench 6 where there is no drug solution container recess 10 toward the center of the drug solution container recess 10. ing. The nozzle 19 is connected by a pipe 20 to a compressor 22 with a high performance filter 21.

The opening 8 has a shutter 23 that can be moved up and down, and by moving it up and down, the effective height H of the opening 8 can be adjusted.

When the clean draft chamber 1 is used for cleaning, etching and the like, a chemical solution container 13 such as a flat vat containing an organic solvent and an acid necessary for the operation is placed in the chemical solution container setting recess 10. When the blower 5, the exhaust device 7 and the compressor 22 are operated, clean air flows down from the high-performance filter 4 at a flow rate Q ₁ , and the working space 3 is kept clean. Further, when the cleaning air jet stream flows from the nozzle 19 toward the chemical liquid container installation concave portion 10 and the gas or vapor of the chemical liquid diffuses to the portion of the work table 6 other than the chemical liquid container installation concave portion 10, the gas Most of the vapor and vapor are guided to the recess 10 for installing the chemical liquid container.

Gas and vapor are generated from the solvent and acid in the liquid medicine container 13 in the liquid medicine container installation recess 10, but since they are heavier than air, the gas and vapor are located above the opening of the liquid medicine container installation recess 10. It does not diffuse, but accumulates in the drug solution container setting recess 10.

The contaminated air guided into the chemical liquid container installation recess 10 and the contaminated air generated in the chemical liquid container installation recess 10 are sucked by the exhaust device 7 via the exhaust port 15 and are in a negative pressure state. It successively flows into the exhaust duct 17. Of the polluted air generated on the workbench 6, the air diffused in the direction of the opening 8 without the attraction of the jet airflow from the nozzle 19 is also sucked in through the exhaust port 12 communicating with the exhaust duct 17. Enter the exhaust duct 17. The above two polluted air streams join together in the exhaust duct 17 to become a polluted air stream having a flow rate Q ₄ , are guided to the outside via the exhaust device 7, purified as necessary, and then released into the atmosphere.

Of the clean air having the flow rate Q ₁ flowing down from the high-performance air filter 4, the remaining portions Q ₁ -Q _{4 which} are not sucked into the exhaust duct 17 are directed toward the opening 8 but before exiting the opening 8. Then, the air flows from the intake port 11 into the duct 9 which is sucked by the blower 5. And high-performance filter 4
After that, it becomes a clean air and enters a circulation path that flows down to the work space 3.

By adjusting the amount of air blown by the blower 5 and the amount of exhaust air of the exhaust device 7 in accordance with the amount of pollutants generated in the work space 3, virtually all uncontaminated air is taken from the intake port 11. It is possible to operate to collect and circulate, and discharge the minimum amount of air out of the equipment to release pollutants. Although it depends on the amount of gas or vapor generated in the chamber 2 within a unit time, the air of the flow rate Q ₄ required for discharging pollutants is usually a small part of the clean air supplied at the flow rate Q _1. It's done.

Since there is no intake port for the blower 5 other than the intake port 11, ambient air of a quantity Q ₂ which is substantially equal to the quantity Q ₄ of polluted air discharged is sucked in from the intake port 11. .. The inflow air amount Q ₂ is not influenced by the change in the opening height H caused by operating the shutter 23. This ambient air is dusty air, but since the amount of clean air in the air curtain shape that intensively flows from the high-performance filter 4 to the intake port 11 serves as a blocking film, it enters the chamber before entering the intake port 11. Therefore, the work space 3 is not contaminated with floating dust.

When the operation is stopped while the blower 5 or the like is operating, it is advisable to provide the chemical solution container setting recess 10 with a suitable perforated lid for preventing chemical solution vapor diffusion. As a result, the leakage of the chemical liquid vapor is further reduced, and on the other hand, the air discharge of the flow rate Q ₄ by the exhaust device 7 is continued through the exhaust port 18, and the air volume balance is kept stable.

[0022]

According to the clean draft chamber of the present invention, based on the above-mentioned structure, the diffusion of the chemical liquid vapor used is minimized, and only a small amount of heavily contaminated air is quickly discharged to the outside from the generation site. Therefore, leakage of contaminated air can be suppressed with an exhaust volume much smaller than the required exhaust volume in the conventional clean draft chamber that sucks and exhausts all the air in the chamber. Therefore, the clean draft chamber of the present invention is provided with a draft chamber as compared with the conventional clean draft chamber in which a large amount of clean air needs to flow while causing a large amount of ambient air to flow in from the opening in order to prevent diffusion of contaminated air. It has the features that a large amount of conditioned air in the room is not consumed and air conditioning cost is not significantly increased, and that the power cost of the blower and the exhaust device is low. In addition, dusty ambient air taken into the air supply system in an amount commensurate with the amount discharged outdoors does not enter the chamber directly because it is blocked by the air curtain-shaped clean air flow from the high-performance air filter toward the intake port. Since it enters the intake port, there is no risk of bringing in dust particles into the chamber. Furthermore, since most of the clean air is recycled and reused, the high performance air filter lasts a long time.

Furthermore, by combining the air injection from the ceiling portion toward the recess for installing the liquid medicine container and the exhaust from the exhaust port provided deeper than the intake port on the workbench, the workbench other than the recess for installing the liquid medicine container is used. Since the contaminated air generated above is reliably discharged without being mixed into the circulating air flow, there is no fear of increasing the degree of contamination of the circulating air, either in the recess for chemical liquid container installation or on the workbench depending on the work content. Can also be used. Even by the above-mentioned air injection, even if there are gas, vapor, etc. diffused around the recess for installing the chemical liquid container, they are
Since the gas is discharged to the outside of the chamber through the exhaust device from the exhaust port provided between the intake port along the edge on the opening side and the recess for installing the chemical liquid container, the degree of contamination of the working space is not increased.

As described above, the clean draft chamber of the present invention is extremely advantageous because it can stably realize a clean working environment at a much lower cost than conventional ones.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional side view of an embodiment of the present invention.

FIG. 2 is a schematic vertical sectional front view of an embodiment of the present invention.

FIG. 3 is a plan view of the workbench 1 in the above-described embodiment.

FIG. 4 is a schematic vertical sectional view showing an example of a conventional clean draft chamber.

[Explanation of symbols]

 1 Clean Draft Chamber 3,33 Work Space 4,31 High Performance Air Filter 5,32 Blower 6,34 Worktable 7,36 Exhaust Device 8,38 Opening 9 Circulation Duct 10 Recessed portion for chemical liquid container installation 11 Inlet 12,15 Exhaust port 13,37 Chemical container 14 Side wall of recess for installing chemical container 17 Exhaust duct 19 Nozzle

Continuation of the front page (72) Inventor Kansai No.7, Otsuka-cho, Yukiya, Ota-ku, Tokyo Alps Electric Co., Ltd.

Claims (1)

[Claims] 1. A blower with a high-performance filter is installed on the ceiling so that clean air can be supplied to the work space from the ceiling, and an exhaust port is provided on or around the workbench to remove polluted air by an exhaust device. In the clean draft chamber for forced discharge, the workbench is provided with an intake port along the edge of the opening, which is used as the air intake port of the blower, and the workbench is provided with a recess for installing a chemical solution container.
An exhaust port is provided between the side wall of the recess for installing the chemical liquid container and the recess for installing the chemical liquid container on the work table and the intake port, and these exhaust ports are communicated with an exhaust device by an exhaust duct. A clean draft chamber, characterized in that a clean air injection nozzle is installed in the ceiling part, which produces a high-speed air flow that flows into the recess for installing the liquid medicine container across the portion where the is not installed.