JPH0593686A - Liquid particle counter - Google Patents

Abstract

(57) [Summary] [Structure] In a submerged particle counter that measures particles in liquids such as water and chemicals, a mechanism that can separate the piping system for measurement from the piping system that performs liquid sampling is provided. Liquid particulate counter with a function to maintain high cleanliness of the measurement part by filtering and circulating a highly clean liquid such as pure water through the piping system for performing standby measurement. Compared to the case of using a liquid particle counter, the measurement time can be significantly shortened and the stability of the measurement data can be obtained. Especially, after measuring a sample with low cleanliness, high cleanliness such as ultrapure water can be obtained. The effect is remarkable when measuring things.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid fine particle counter used for measuring particles in pure water or chemicals used in the manufacturing process of semiconductor devices, etc. It protects the measurement part and enables efficient and reproducible measurement.

[0002]

2. Description of the Related Art FIG. 2 is a piping diagram of a conventional liquid particle counter.

There is only one piping system for liquid sampling and one piping system for measurement, which is shown by reference numeral 8 in the figure, and the liquid flows in the piping at the same flow rate during measurement and during standby.

Liquid such as pure water and chemicals to be measured is sucked from the sample inlet 12 into the particle counter sensor portion indicated by 1 in the figure, and passes through the liquid flow path portion 8 into the transparent particle detection cell 2. Reach

When the particle detection cell is irradiated with laser light 5 emitted from the laser optical system 4 and particles are present in the liquid in the particle detection cell, the laser light scattered by the particles is transmitted to the lens system 6. Thus, the light is collected and photoelectrically converted by the light receiving unit 7, and the particle size of particles is determined by the wave height analyzer counter 3, and the number of particles is counted.

When changing the liquid to be measured here, the sample inlet is changed to the liquid tank.
When the kind of the liquid is different or the particle level is significantly different, a large amount of the sample liquid is flown into the pipe to perform replacement, and then the measurement is performed.

[0007]

However, in the conventional method, since the measuring portion usually has a small flow rate, a large amount of the measuring liquid is flown in the piping in order to remove the influence of contamination adhering to the pipe wall in the sampling pipe. Since it is necessary, measurement becomes difficult when the sample amount is limited.

When measuring a liquid having a high degree of cleanliness such as pure water, a large amount of pure water is poured so as not to be affected by the sample measured immediately before, and therefore the measurement takes a long time. There was a problem such as requiring

[0009]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the above-mentioned conventional method, and is a mechanism capable of individually separating the piping system for measurement from the piping system for liquid sampling. Is installed, and the pipe system for performing the standby measurement is provided with the function of constantly maintaining a high cleanliness of the measurement part by filtering and circulating a highly clean liquid such as pure water.

[0010]

EXAMPLE FIG. 1 is a schematic diagram of the internal piping of a laser light scattering type liquid fine particle counter according to the present invention.

Liquid such as pure water and chemicals to be measured is sucked from the sample introduction port 12 into the particle counter sensor portion indicated by 1 in the figure, passes through the liquid flow passage portion 8 and is transferred to the transparent particle detection cell 2. Reach

When the particle detection cell is irradiated with the laser beam 5 emitted from the laser optical system 4 and particles are present in the liquid in the particle detection cell, the laser beam scattered by the particles is transmitted to the lens system 6. Thus, the light is collected and photoelectrically converted by the light receiving unit 7, and the particle size of particles is determined by the wave height analyzer counter 3, and the number of particles is counted.

Here, a switching valve 9 is provided in the middle portion of the liquid flow path portion 8 in front of the sample introduction side and in front of the drainage port so that the pure water which has permeated the sample or the filter can be switched and flowed if necessary.

At the time of normal measurement, the sample is sucked from the inlet 12 as in the conventional method, and is discharged from the outlet 13 through the particle detection cell.

After the predetermined measurement is completed, the switching valve 9 is operated until the next measurement is started to supply the pure water that has permeated the filter into the pipe, and while the particles are initially counted and the pipe is counted. After flowing out for a certain period of time until the chemical solution inside was discharged, the switching valve on the discharge side was operated and pure water was circulated by the circulation pump to keep the inside of the pipe and the particle detection cell part in a clean state.

In the above state, the apparatus stands by in preparation for the next measurement, so that the measurement could be started smoothly when the measurement of a new measurement sample was started.

Further, it is possible to obtain the effect of neutralizing the chemical liquid in the pipe by selecting the kind of the circulating liquid as required.

[0018]

As a result of the measurement using the liquid fine particle counter adopting the method according to the present invention, the measurement time is greatly shortened and the measurement is performed as compared with the case of using the liquid fine particle counter according to the conventional method. The stability of the data could be obtained, and the effect was remarkable especially in the case of measuring a sample having a low cleanness and then measuring a sample having a high cleanliness such as ultrapure water.

[Brief description of drawings]

FIG. 1 is a schematic diagram of piping of a liquid particle counter according to the method of the present invention.

FIG. 2 is a schematic diagram of piping of a liquid particle counter according to a conventional method.

[Explanation of symbols]

 1 particle counter sensor part, 2 particle detection cell, 3 wave height analyzer counter, 4 laser optical system, 5 laser light, 6 lens system, 7 light receiving part, 8 liquid flow path part, 9 switching valve, 10 filter, 11 circulation Pump 12 sample introduction port, 13 drainage port,

Claims (1)

[Claims] 1. A standby system is provided with a mechanism capable of individually separating a piping system for measurement from a piping system for liquid sampling in a submerged particle counter for measuring particles in liquid such as water and chemicals. <A liquid fine particle counter characterized by having a function of maintaining high cleanliness of a measurement unit by constantly circulating and circulating a highly clean liquid such as pure water through a piping system for measurement.