JPS6161609A - Process for cleaning air to superhigh purity - Google Patents

Abstract

PURPOSE:To realize cost reduction by performing primary cleaning using a filter, and performing also secondary cleaning such as pretreatment by the addn. of steam, etc. condensation by adiabatic expansion, collection of chemical material by using a filter medium, etc. CONSTITUTION:Contaminated air is guided into a pretreating apparatus 1, and fine water particles are added from a nozzle 9 while the air passes through a filter medium 5, and a sterilizing device 6. Then, the air is transported to a secondary cleaning device 3 with a compressor 2 and the temp. and humidity are conditioned by a heater 7 and a humidity controlling device 11b. The air is guided into an introducing chamber 14a where it is expanded adiabatically to condense the moisture. When the air passes through a throttle plate 15a, the condensation is progressed further. Fine water particles are grown in the expanding chamber and condensation chamber 17a, and are deposited on a collecting material 18 in a collecting chamber 19a. When the water content attains a certain amt., it is discharged through a drain pipe 22 in the form of liquid mixture.

Description

[Detailed Description of the Invention] <Industrial Application Fields> This invention is applicable to manufacturing factories for electronic parts such as LSI and VLSI that require extremely high precision, and to so-called biotechnology technology represented by gene replacement technology. The present invention relates to a method for ultra-cleaning air to obtain an ultra-clean environment, which is a problem in sterile environments required in practical factories and laboratories in the technical field, medicine, biology, food industry, and other fields.

Conventional techniques〉 Conventional air purification methods are broadly divided into mechanical dust collection and electrostatic collection, but in order to obtain a high dust collection rate with mechanical dust collection, for example, an indoor pack filter type It is said to be about .3μ, and even with electrostatic precipitation, it is thought that the limit is about 0.01μ.

<Problems to be solved by the invention> In contrast to the above-mentioned conventional technology, for example, ultra-ultra LSI
In the manufacturing environment of LSIs with an IC density of 1 to 4 megabits, called 0.1 to 0.04 μm solid particles are controlled, and it is clear that the mechanical separation method cannot handle this. According to the above, although it is partially satisfactory, it is still insufficient near the minimum particle diameter, and the electrostatic precipitator has the disadvantage of extremely high initial cost.

Means for Solving the Problems> In the air ultra-cleaning method of the present invention, first, the air to be purified at room temperature and pressure is passed through a filtration device or a filter to collect relatively coarse particles. Next, the air to be purified is subjected to pre-treatment including heating to a constant temperature, compression to a constant pressure, and addition of high-purity steam or minute water droplets, and then the pre-treated air is shaped into a cylinder. The air to be purified containing the condensed water is sent into the purifier and passed through a diaphragm plate that partitions the inside and has a number of diaphragm holes, which causes adiabatic expansion and condenses the water contained therein. It is characterized by filling the air with a heat-resistant filtration replenisher and performing a secondary cleaning process in which chemical substances contained in the air to be purified are collected in moisture.

Function: In this invention, relatively coarse particles in the air that are easy to collect mechanically are collected in the primary cleaning process, and in the preliminary treatment, the air to be cleaned is heated to high temperature and pressure, so that it can be used for the next secondary cleaning. Increasing the expansion and temperature change due to adiabatic expansion in
Steam or minute water droplets are added to increase the amount or content of condensed water above a certain level. The water added at this time is of high purity such as distilled water so as not to interfere with air purification.

In the process of secondary cleaning treatment, the moment high-temperature, high-pressure air passes through the iris plate, volumetric expansion occurs, and the contained water vapor becomes saturated and condenses into minute water droplets.

These water droplets are based on various solid particles in the air to be purified from the moment they are generated, but as they grow and combine with other water droplets and particles in the collection chamber, they adhere to the filtering material, and the It continues to grow even after attachment.

The solid particles that are attached and collected by the Uni contain all kinds of dust in the air to be purified, such as metal and non-metal fine particles, and chemical substances such as nitrate ions and sulfate ions are dissolved in the moisture. Collection of these is also possible.

Some of the solid particles collected in this way remain attached to the collection material, while others flow out from the purifier to the outside together with water droplets that have condensed and grown, and all solid particles and air are removed from the purifier. Various chemical substances contained in the air are removed and the air is discharged outside as ultra-clean air.

〈Example〉 Figure 1 shows one of the air ultra-cleaning devices for carrying out the present invention.
As an example, the apparatus is comprised of a pretreatment device 1 that performs primary cleaning and pretreatment, and a secondary purifier 3 connected to its rear end via a compressed air blower 2.

In the pretreatment device 1, a filter material 5 made of glass wool, stainless steel wool, mesh material, a filter, etc. is inserted into the opening end of a striped main body 4 for introducing air, and a filter material 5 made of glass wool, stainless steel wool, mesh material, a filter, etc. Sterilizer 6 using etc.
is inserted, and a heating 7 consisting of a heater or the like is further inserted behind it.

A compressed air blower 2 consisting of a blower or the like is provided in a connecting part 8 connecting the rear end of the pretreatment device 1 and the front end of the secondary purifier 3.
A nozzle 9 is inserted in front of the compressed air blower 2 to eject high-purity water vapor or fine water droplets. This nozzle 9 is connected to an externally provided humidifier 11b, from which highly purified water vapor or particulate water droplets are supplied.

A temperature sensor 10a and a humidity sensor 10)+ are attached to the front end of the purifier 3 to constantly detect the temperature and humidity of the air to be purified flowing into the purifier 3, and send the detection signals to the control device 11.
I am sending it to a.

This control device 11a includes the heating device 7 and the humidifier 11 described above.
b, and heats and controls the air flowing into the purifier 3 so that the temperature and humidity of the air to be purified are always kept above a certain level.

The humidity controller 11b is filled with high-purity water that does not contain any impurities, and this water contains dermanium to help dissolve small particles such as mediums that are difficult to dissolve in water in the air to be purified into water droplets. It is mixed as a solution.

The secondary purifier 3 has a cylindrical main body 12 and is equipped with a cooling jacket 13 that cools the main body 12 by circulating a refrigerant such as cooling water or air around the outer periphery of the main body 12, and the air to be purified is introduced into the front end of the jacket 13. An introduction chamber 14a is provided, and a squeeze plate 15a is further provided to partition the inside of the main body 12. This squeeze plate 15a has a squeeze hole 16 made up of a large number of small holes, and a condensation chamber 17a made of a certain space is formed behind the squeeze hole 16.

At the rear of the condensation chamber 17a, there is provided a collection chamber 19a having a certain volume filled with a heat-resistant bolt 18 made of stainless wool, glass wool, stainless mesh, etc.
Behind it is the second stage introduction chamber 14a, the L burr plate 15b,
Condensation chamber 17b.

A collection chamber 19b is formed, and the thickness, volume, number of stages, etc. of these binding plates and the collection chamber are determined in design depending on various conditions required for ultra-cleanliness.

A rear collection pan 20 is provided at the rear of the last stage collection chamber 1.9b in the purifier 3 for colliding the air to be purified discharged therefrom to collect solid particles therein. An exhaust port 21 for discharging secondary purified air is attached to the rear end of the purifier 3 behind it. In addition, a plurality of drain pipes 22 are inserted into the bottom of the secondary purifier 3 to discharge water droplets containing solid particles and chemicals grown inside the secondary purifier 3, particularly in the collection chambers 19a and 19b. All components combined with water in the liquid are discharged while remaining contained in this liquid.

With the above-mentioned device, contaminated air from a room, etc. is first introduced into the pretreatment device 1, where relatively large circular particles are attached and collected by the filter material 5 at the front end, and then sterilized by the next sterilization device 6. conduct.

Next, in the heating device 7, in order to promote the condensation of moisture during the expansion action in the secondary cleaning, heating is performed according to the detected value of the temperature sensor 10a, and then heating is performed in order to adjust the moisture necessary for the condensation. High purity water vapor or minute water droplets are added through the nozzle 9.

Subsequently, the compressed air blower 2 applies a constant pressure to the air to be cleaned and blows it into the secondary purifier 3. The air at this time is the heating device 7 and the humidifier! 1b, and the temperature and humidity are adjusted so that the range of temperature drop due to adiabatic expansion is as large as possible and the amount of water condensation is the largest, and the most suitable range is about 90°C-zoooC. The temperature drop in the case is about 30°C to 60°C (
However, the difference between the inlet and outlet of Cleaner 3) When the air to be purified, which has been made high temperature and high pressure and contains a certain amount of moisture (steam) as described above, is introduced into the introduction chamber 14a, the compressed air expands and the temperature drops by a certain amount due to adiabatic expansion. At the same time, the water vapor condenses to some extent and becomes minute water droplets. Further, when passing through the aperture plate 15a, the adiabatic expansion occurs even more significantly, and condensation of water vapor also occurs here.

These condensed water droplets not only dissolve chemical components in the air, but also contain microparticles contained in the air as their core. In this way, as the temperature drops, microscopic water droplets move into the expansion chamber 14.
Even in the process of turbulence in the condensation chamber 17a and the condensation chamber 17a, it grows by combining with microparticles and other water droplets in the air.
By introducing the growing particles into the trapping material 18, the growing particles adhere to the collection material 18 inside the collecting material 18, resulting in more remarkable bond growth.

As a result, a combination of fine particles containing moisture is sequentially attached to and collected on the collection material 18, and when a certain amount of moisture is reached, it becomes a mixed liquid and is dripped at the bottom of the secondary purifier 3 and is discharged through the drain pipe 22. +flS is discharged.

The above-mentioned action is carried out by the second stage introduction chamber 14b, [, the rising plate 15b, ? The same process is repeated in the M-binding chamber 17b, etc., to perform more complete secondary cleaning, and the water is finally purified by the rear collection dish 20 and discharged to the outside.

Although the expansion of the air to be purified, the drop in temperature, and the growth of moisture condensed particles in the secondary purifier 3 have been explained in relation to adiabatic expansion, in reality they are caused by polytropic changes.
chan8c) + polytrop
e) + instant cooling bond, squeezing, expansion, thermal deposition (thermophoresis l'1
It includes various types of M-like or partially overlapping gas thermal effects (these may be collectively referred to as "expansion phenomena") expressed by concepts such as IIJ) and the like.

Due to the above-mentioned actions and the collection action in the collection chamber, the size of the solid particles collected in the second purifier 3 is at least 0.
Furthermore, such fine solid particles have a size of 0.1 to 5 μ and have a large water equivalent of 40 to 60%, so solid particles can be collected by binding them with fine particles of condensed water. The amount that can be achieved is very high.

Incidentally, if it is necessary to further perform temperature control or humidity control on the clean air discharged from the secondary purifier 3, this may be done using a separately provided device.

<Effects of the Invention> As a result of this invention having the structure described above, it is possible to purify indoor air at room temperature and pressure with extremely high efficiency, and to collect much smaller solid particles than other mechanical fishing methods. Can be done. In addition, the performance of these methods is not inferior to that of electrostatic precipitators in the United States, and they can also collect chemical components such as nitrate ions and sulfate ions in the air to be purified. Since the pressurization by the blower 2 has little negative impact on other departments, it is possible to increase the volume of air flow, and the volume and length of the collection chamber and the packing density of the collection material can be increased (by increasing the volume and length of the collection chamber, and the packing density of the collection material). Since the flow can be slowed down, the collection rate of solid particles and chemical substances can be increased to nearly 100%.These equipments have the advantage of being considerably more cost-effective than electrostatic precipitators.

In addition, the method of the present invention can be used in a wide range of fields, such as the manufacturing field of precision electronic parts, the microbial application field, etc., as well as the industrial, agricultural, medical, and academic fields as already mentioned. It can be fully used for general household environmental cleaning purposes.

[Brief explanation of the drawing]

FIG. 1 is an overall cross-sectional view showing one example of an apparatus used for carrying out the method of the present invention. 1: Pre-treatment device 2: Compression blower 3: Secondary purifier 4: Main body 5: Filter material 6: Sterilizer 7: Heating device 8: Connection portion 9: 7 screws 10a: Temperature sensor-10b Humidity sensor 11a: Control device 1]l):Ill,
'ii Humidifier 12: Main body 13: Cooling jacket 14a, 14b: Introduction chamber 15a, 15b: L
Plate board 16: Squeeze holes 17a, 17b: ljJ joint chamber 18: Collection material 19a, 19b: Collection chamber
20: Rear collection book 21: Exhaust port 22: l'
Written amendment to the Ren pipe procedure (spontaneous) November 5, 1980 Patent Application No. 185138 2, Title of the invention Air ultra-purifying method 3, Relationship with the person making the amendment Patent applicant Address Kanagawa Prefecture 840 Junisho, Kamakura City Name: Ken Aoi 4, Agent
■340 Address: 2nd floor, 1139 Niisato-cho, Soka City, Saitama Prefecture
Contents of the amendment The following points are amended in the specification of the present application. 1. In lines 2 and 3 of page 7, replace the phrase “The air to be purified is difficult to dissolve in water” with “It is difficult to dissolve in water in the air to be purified.”
Delete one character and add one character. 2. On page 11, lines 12 to 14, the phrase ``Moreover, it is as large as this...by 40 to 60%'' is replaced by ``Moreover, such solid particles (such as soil particles) are Approximately 35% for diameters of 5 to 50μ, approximately 61% for diameters of 0.1 to 5μ
``The smaller the particle size, the larger the particle size.''

Claims (1)

[Claims] 1) Primary cleaning is performed by passing the air to be purified at room temperature and normal pressure through a filtration device or filter to collect relatively coarse particles, and then heat treatment of the air to be purified to a constant temperature and compression treatment to a constant pressure. The air to be purified after the pretreatment is then sent into a cylindrical purifier, and the inside is partitioned and a squeeze hole consisting of many small holes is applied. By passing through a perforated diaphragm plate, adiabatic expansion is caused to condense the contained moisture, and the air to be purified containing the condensed water is sent to a collection chamber filled with a heat-resistant filtration replenisher and passed through to collect fine particles. A method for ultra-cleaning air, which includes collecting particles and performing secondary cleaning in which chemical substances contained in the air to be purified are collected by including them in moisture.