Dust monitoring

There are two types of dust monitor one is the fixed filter type and another is the moving filter type. 

The ventilated air and gaseous waste from the controlled area are released through the stack after dealing with high efficiency particulate air filters. There are two methods of continuously monitoring the concentration in exhaust gas. One is to measure the gas directly with a detector inserted into the stack or duct and the other is to measure a portion sampled from the exhaust air with a dust monitor or a gas monitor. 

Fig. 15.22 Physical arrangement of the Philips PW 9770 Dust Monitor. (Courtesy of Philips).

Continuous monitoring data for a large-scale automotive foundry are given in Annex 2. These data show dust monitoring for sand preparation, sand transport and shot blasting. 

The air, after passing the dust-monitoring device, is passed through a C.W.S. filter and then into the annular type ionization chamber. The purpose of the second filter is to further ensure dust-free air. The annular type chamber consists of two concentric cylinders and utilizes maximum geometry by allowing the radioactive air or gas to pass through the innermost cylinder while the outer chamber is filled with argon gas at a pressure of 20 atm. 

A=UV spectrometer-multicomponent B=Opacity motor C=Velocity meter/temperature probe D=0 analyser E=CO monitor F=Dust monitor... 

Figure 3.3.10 Laser nephelometer - direct reading dust monitoring instrument...

K. L. Williams and R. P. Vincent, Evaluation of the TEOM Dust Monitor, Bureau of Mines Information Circular, 1986, United States Department of the Interior. 

The best way to detect background dust sources is to use an instantaneous dust monitor with data logging capability. By monitoring the worker s exposure throughout the entire workday, significant dust-producing events can be identified and controlled. 

Radiation control Remote high dose-rate measuring instrument Dust monitor Contamination inspection apparatus Waste package contamination and dose rate monitor... 

---