Development of a multi channel airborne particulate matter detector by electrical technique

การพัฒนาเครื่องตรวจวัดฝุ่นละอองในอากาศแบบหลายย่านวัดด้วยเทคนิคทางไฟฟ้า

Name: Artit Yawootti

Classification :.DDC: 681.2

LCSH: Detectors

LCSH: Air -- Pollution

LCSH: Dust control

LCSH: Electric fields

Abstract: This thesis is about development of a multi-channel airborne particulate matter detector by electrical technique (PMx detector). The PMx can automatically measure and rapidly report a mass and number concentration. The PMx detector consists of the sample conditioning inlet section, the particle charging section, the particle size classification and collection, the particle detector with electrometer circuit, analog to digital converter, personal computer, operating software flow control system, electric power system and other accessory device. The operation starts at a vacuum pump sucking the airborne particulate matter into the sample conditioning inlet section. Air humidity is removed by diffusion drying with a silica gel. Then the sample air passes through the particle charging section and receive electric charge. The sample air are separated for PM10, PM2.5 and PM1.0. This part employs inertial impaction principle where the particles are accelerated and fling to the impactor plates. Particles that are bigger than a cutoff diameter are collected on this plate, while the smaller particles can pass through to the exit. The PM passes through and collected on a filter in the Faraday cup, then sending an electrical charge to an electrometer circuit for signal converting and amplifying. The electrical signal from measuring the airborne particulate matter is processed by the personal computer. Analytical and numerical methods were also used to estimate and validate the PMx detector. The flow analysis by COMSOL was conducted for the air conditioning inlet section, the particle charging section and the particle size classification. Particle trajectory analysis and electric field analysis were also carried out. Orcad PSpice software was used to simulate the low level signal amplifier circuit and comparing with a numerical calculation and laboratory test. The laboratory test was used to validate theoretical results, and to evaluate performance of the diffusion dryer and nano-particle loss, performance of the particle charging section under the temperature and humidity changes, performance of the particle size classification by the SEM analysis, a particle loss in the Faraday cage, stability of the electrometer circuit, and a long time test comparing with TEOM, Beta ray and light scattering technique since June 2013 to May 2016. The measurement data in a minute, hour and 24 hours average were compared and found to have high correlation about 0.98.

Chiang Mai University Library

Address: CHIANG MAI

Email: cmulibref@cmu.ac.th

Name: Tawatchai Charinpanitkul

Role: Chairman

Name: Nakorn Tippayawong

Role: Member

Name: Thawan Sucharitakul

Role: Member

Name: Det Damrongsak

Role: Member

Name: Khanoksak Sopajaree

Role: Member

Name: Somporn Chantara

Role: Member

Created: 2017

Modified: 2020-01-09

Issued: 2020-01-09

วิทยานิพนธ์/Thesis

application/pdf

CallNumber: Th 681.2 A791D

eng

DegreeName: Doctor of Engineering

Level: Doctoral Degree

Descipline: Energy Engineering

Grantor: Chiang Mai University

©copyrights Chiang Mai University

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