JPS63151339A - Induction type aerosol feeder - Google Patents

Abstract

PURPOSE:To stably supply an aerosol at predetermined temp. for a long period of time, by arranging a double pipe having an inside flow passage and an outside flow passage, a mixing chamber communicating with one end of the double pipe and the gaseous mixture flow passage communicating with the aforementioned mixing chamber. CONSTITUTION:The open air A is allowed to pass through an air filter 12 by an oilless pump 11 to obtain purified air B. The purified air B is sent out to the inside flow passage being one of the flow passages of a double pipe 2 by the oilless pump 11 and further injected in a mixing chamber 5. The outside flow passage being the other passage of the double pipe 2 communicates with the open air A and, when the purified gas B is injected from the terminal of the double pipe 2 in the mixing chamber 5 by emitting pressure, the open air A is sucked in the mixing chamber 5 by the induction action of the purified air B. The gaseous mixture C of the open air A and the purified air B mixed in the mixing chamber 5 is sent out to a required external apparatus through a gaseous mixture flow passage.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an induced aerosol supply device, and in particular to an induced aerosol supply device suitable for diluting constant concentration aerosol with clean gas and supplying a required concentration of aerosol over a long period of time. Concerning vessels.

Support Summer 3 Contamination diffusion tests in clean rooms required in semiconductor device manufacturing processes, air filter leakage tests,
Air containing a known concentration of particles is used for purposes such as on-site performance testing of filters installed in ducts. This test air is usually supplied by mixing particles from a standard particle generator or the like into clean air. However, this conventional method has problems such as variations in particle size due to functional limitations of the standard particle generator, variations in particle concentration due to similar causes, and contamination of oil particles from the blower.

is trying to do so. Accordingly, the problem to be solved by the present invention is to stabilize the particle size and particle concentration in aerosol such as test air and to prevent oil particles from being mixed into the aerosol.

1. To occupy - Referring to FIGS. 1 and 2, in the induced aerosol supply device 1 according to the present invention, one end of the inner flow path 3 and the outer flow path 4 of the double pipe 2 is connected to the mixing chamber. 5, and the mixing chamber 5 is further communicated with a mixture flow path 6. Clean gas is fed into the mixing chamber 5 from one of the internal and external channels 3.4 of the double pipe 2, and a constant concentration is maintained through the other channel by the attraction of the flow of the clean gas. The aerosol is sucked into the mixing chamber 5, and the mixed aerosol generated in the mixing chamber 5 is sent to the air mixture flow path 6.

For example, arrow B is added to the inner flow path 3 of the double pipe 2 as a clean gas.
The clean air shown by arrow A is introduced, and the outdoor air (hereinafter referred to as outside air) shown by arrow A is made into a constant concentration aerosol and sucked by the above clean air flow through the outer flow path 4.

The operation will be explained with reference to the example shown in FIG. This cleaning body 51 B is sent out to one flow path of the double pipe 2, that is, the inner flow path 3 in the illustrated example, by the discharge pressure of the oilless pump 11, and further from the end of the inner flow path 3 to the mixing chamber 5. It is ejected inside. The other flow path of the double tube 2, that is, the outer flow path 4 in the illustrated example, communicates with the outside air A, and the clean gas B is blown out from the double tube end bundle in the mixing chamber 5 by the above discharge pressure. During this process, outside air A is drawn into the mixing chamber 5 by the attraction of the clean gas B.

The mixture C of the outside air A and the clean gas B thus mixed in the mixing chamber 5 is sent to a required external device (not shown) via the mixture flow path 6.

It is generally known that the particle size distribution and particle concentration in outside air A, that is, outside air, are extremely stable. On the other hand, the particle concentration of the clean gas B obtained by purifying the outside air A with a suitable air filter 12 is kept much lower than that in the outside air. Therefore, as long as the particle size distribution and particle concentration in outside air A are stable, the particle size distribution and particle concentration of mixture C generated by mixing outside air A and clean gas B in mixing chamber 5 can be kept stable for a long time. becomes possible.

Further, since the two gases are directly mixed by attracting the outside air A by the flow of the clean gas B after being purified by the air filter 12, there is no risk of contamination by oil droplets or other foreign matter from the pump.

The mixing ratio of outside air A and clean gas B can be controlled by adjusting the jetting speed of clean gas B into the mixing chamber 5 and adjusting the strength of its attracting effect, so that the particle size in the mixture C can be controlled. It is possible to control the distribution and particle concentration within certain limits.

Preferably, in order to ensure the attraction of outside air A at the outlet of the double pipe 2 in the mixing chamber 5, the ends of the inner flow path 3 and the outer flow path 4 at the outlet are throttled, as shown in FIG. An inner orifice 3a and an outer orifice 4a are formed. If necessary, a flow meter 13 may be arranged on the inlet side of the inner flow path 3 and outer flow path 4 of the double pipe 2 as shown in FIG.

Although the example of mixing outside air A and clean gas B has been described above, it is clear to those skilled in the art that the aerosol supply device of the present invention can be applied to any aerosol made of gas containing suspended particles.

The operating characteristics of the aerosol supply device 1 according to the present invention were measured using the apparatus shown in FIG. That is, by adjusting the speed of the oilless pump 11, the flow rate of the clean gas B sent to the aerosol supply device 1 via the air filter 12 is controlled, and while the flow rate is monitored by the flow meter 13, the mixture C is The particles inside were measured. In this case as well, outside air A was supplied to the outer wave path 4 of the double pipe 2, and clean gas B was supplied to the inner flow path 3 thereof.

FIG. 4 shows an example of measurement results of changes in particle concentration, that is, dust concentration, in mixer C with respect to changes in the flow rate of clean gas B. In the figure, curve P shows the concentration of particles with a particle size of 0.3 μm or more, and curve Q shows the concentration of particles with a particle size of 0.5 μm or more. As is clear from the figure, the particle concentration in the mixture C can be controlled by adjusting the flow rate of the clean gas B.

An example of measured values of the particle concentration in the mixture C over time is shown in FIG. Particle size of 1 μm is a problem in clean rooms
It was confirmed that the particle concentrations of the following particles remained stable for more than 3 hours.

Conventionally, it has been difficult to stabilize the particle concentration for more than one hour.

As explained in detail, the induced aerosol supply device according to the present invention draws a constant concentration aerosol into the mixing chamber by the attracting action of the clean gas flow introduced into the mixing chamber to form a mixed aerosol. Since it generates , it has the following effects.

(a) DOP (dioctyl phthalate), PSE, (
The required particles can be supplied by using atmospheric dust without using standard particle generators such as polystyrene latex.

(b) As long as the particle concentration in the atmosphere is stable, dust generation and concentration can be stabilized for a long time.

(c) It is possible to control the dust concentration within a certain range by adjusting the flow rate of the clean air flow that acts as an attraction.

(d) Since it can be made extremely small, it can be used for on-site measurements in narrow spaces such as clean rooms.

(e) It can also be used as a supply device for aerosols other than air.

(f) In addition to being an aerosol supply device, it can also be used as an aerosol diluter.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of one embodiment, FIG. 2 is an explanatory diagram of usage, FIG. 3 is a block diagram of a characteristic measuring device, and FIGS. 4 and 5 are graphs showing characteristics. 1...Aerosol supply device, 2...Double pipe,
3...Inner channel, 4...Outer channel, 5...
Mixing chamber, 6...Mixture flow path, 11...Oilless pump, 12...Air filter, 13...Flow meter, A...Outside air, B...Clean gas, C...
・Mixture.

Claims (1)

[Claims] A double pipe having an inner flow path and an outer flow path, a mixing chamber communicating with one end of the double pipe, and a mixture flow path communicating with the mixing chamber; Induction by attracting a constant concentration aerosol into the mixing chamber through the other channel of the double pipe by the attraction of the clean gas flow sent into the chamber, and sending the mixed aerosol to the mixture channel. Type aerosol supply device.