JPH0583138B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a device for measuring the particle size distribution of droplet-like particles, that is, mist, in exhaust gas in a process of treating exhaust gas discharged from a factory. Therefore, it is a suitable device to be installed at the outlet of a scrubber or the like used in the exhaust gas treatment process.

(Prior art) To measure the particle size distribution of aerosol particles, aerosol is ejected downward from a nozzle at high speed, and is collected by a disk-shaped collision plate installed directly below the nozzle. The method is common. In other words, particles in an aerosol obtain an inertial force proportional to the square of their particle size, and this method takes advantage of the fact that only particles with an inertial force above a certain level collide with and adhere to this collision plate. A funnel-shaped nozzle was constructed in several stages, with the diameter of the ejection port decreasing toward the bottom, and the particles collected on each collision plate installed directly below each nozzle were collected at each stage and weighed. There is a device called a cascade impactor that determines the particle size and distribution amount.

(Problem to be Solved by the Invention) However, the above device stores the aerosol particles to be measured on a collision plate for a certain period of time, and then takes them out to the outside and weighs them, so the actual exhaust gas processing time is There is a time lag, and in addition, if the particles are in liquid form, the mist collected on the collision plate may flow out from the collision plate, or may even be re-splattered. There was a risk that the amount of diameter distribution could not be obtained.

(Means for solving the problem) For this purpose, since mist is in a liquid state and is generally a volatile component, if it is forcibly evaporated by heating on the collision plate, the latent heat of evaporation will immediately deplete the mist. Moreover, instead of providing a nozzle and a collision plate, if the particle size before and after evaporation is measured by a light scattering method in space, all of the above-mentioned drawbacks of the conventional method can be eliminated. This invention was developed focusing on the above points.

(Embodiment of the invention) In the figure, 1 is an aerosol introduction port,
It is surrounded by a cylindrical clean air injection pipe 3 connected to a sheath air inlet 2. 4 is a vertical cylinder-shaped detection chamber, 5
is the outlet connected to the suction pump.

The circumferential surface of the detection chamber 4 includes a light source 6 provided outside the detection chamber, a condensing lens system 7, and a window hole through which each light ray emitted via the light source 8 and condensing lens system 9 passes, and these light rays. A window hole is provided through which the scattered light generated when the particle hits the particle, and light receivers 10 and 11 are provided on the outside to receive the scattered light. , 13 to a comparison analyzer 14. In addition, a heating device 1 is installed in the middle of the circumferential surface of the detection chamber.
5. A window hole is provided through which a heating source consisting of a heating beam introduced through the lens system 16 or a heating source such as a microwave is passed.

(Function, effect) The aerosol enters the detection chamber 4 through the inlet 1, wrapped in an inner tube with clean air, and the particles are irradiated with light from the light source 6, and the scattered light from the irradiated particles is received. The scattered light intensity is detected by a device 10, and the intensity of the scattered light is processed by a calculator 12 to measure the particle size.

Next, the mist is heated by a heating source using heat rays from the heating device 15, and volatile components are evaporated to become solid particles. The solid particles are irradiated with light from a light source 8, and the scattered light is detected by a light receiver 11 to measure the particle size.The solid particles are analyzed by a comparative analyzer 14 together with the amount processed by the light receiver 10. A required particle size distribution of mist can be determined.

The present invention analyzes the mist to be measured as described above directly using a light source and a heat ray without passing it through a nozzle or collision plate, and is extremely efficient because the measurement is performed in real time.

[Brief explanation of the drawing]

The drawing is an explanatory sectional view of the invention. 1...Inlet, 3...Clean air injection pipe, 4...
Detection chamber, 5... Outlet, 6, 8... Light source, 7, 9
...Condensing lens, 10, 11... Light receiver, 12,
13... Arithmetic unit, 14... Comparison analyzer, 15...
heating device.

Claims (1)

[Claims] 1. A vertical cylindrical detection chamber with an aerosol inlet surrounded by a clean air injection pipe at the upper end and an outlet connected to a suction pump at the lower end. Each arrangement includes a pair of upper and lower mechanisms that measure the size of the particles by exposing them to the particles and receiving the scattered light, and a heating mechanism located between these measuring mechanisms that emits heat rays to evaporate the liquid components of the mist. A device that measures the particle size distribution of the installed mist.