Dust monitoring of exhaust gases from manufacturing processes - Manufacturing, Other

DynOptic dust monitors use the innovative Dynamic Detection Principle (DDP) to measure dust and particulate within exhaust gases from various manufacturing processes. DDP, or optical scintillation as it sometimes referred to, measures the dynamic fluctuation in light transmission as dust particles move through a light beam. This dynamic fluctuation derives from temporal distributions of the dust particles which attenuate the light beam. The more dust present in the exhaust, the greater the amplitude of these fluctuations. DDP instruments calculate the dynamic response, or the ratio of light variation to light intensity, which for particular applications, is proportional to dust concentration and when calibrated against standard reference measurements, this can be presented as a reading in mg/m³.

DDP, or optical scintillation as it sometimes referred to, measures the dynamic fluctuation in light transmission as dust particles move through a light beam. This dynamic fluctuation derives from temporal distributions of the dust particles which attenuate the light beam. The more dust present in the exhaust, the greater the amplitude of these fluctuations.

DDP instruments calculate the dynamic response, or the ratio of light variation to light intensity, which for particular applications, is proportional to dust concentration and when calibrated against standard reference measurements, this can be presented as a reading in mg/m³.

Unlike the standard transmission technique, DDP has immunity to gradual reductions in the absolute intensity of the light signal. Therefore, DDP instruments have the advantage that they are significantly less susceptible to drift with time, temperature or dirtying optics, than traditional opacity monitors and less sensitive to misalignment. In practice, this means that the instruments require less maintenance.

In order to determine whether DDP is suited to your application, it is necessary to consider a number of factors such as the typical size distribution of the particulates to be measured, whether they have constant or variable physical properties and the ease of which the heads can be accessed for routine cleaning of the optical surfaces. The following table summarises the key requirements for using DDP as compared to the more traditional opacity monitors.

Parameter

DDP

Opacity

Optimum particle diameter (mean of the particle diameter mass distribution)

>10μm

<1μm

Dependence on optical properties of the particles

Low

High

Dependence on optical surface contamination

Low

High

Dependence on noise pick-up (optical or electrical)

High

Low

Dependence on gas flow velocity

High (<3m/s)
Low (>3m/s)

Low