1. SMOKE DENSITY MEASUREMENT
Particles emitted give rise to a nuisance factor
Plume visibility and haze due to finer particles
Ground level deposits in the case of larger particles
Appearance of plume assessed according to Ringelmann scale of plume greyness
Used for spot check
Shades of grey from white to black
Ringelmann 0 (white) to Ringelmann 5 (Black) in steps of 20% obscuration
<40% or Ringelmann 2 is legal requirement

2. SMOKE METER Photo cell type
Focused light beam through the duct or chimney on a photo cell
Variation in signal of the photo cell a measure of variation in obscuration of light source due to smoke and dust
Difference exists between what the meter shows and Ringelmann chart as Light path and chimney diameter not same

3. SMOKE METER Deposits of particles on the camera lens and Receiver
Aluminium tubes of length (4:1 dia for coarser and 16:1 for finer ) eliminates deposits
Zero drift due to ageing of components and dust
Misalignment of lamp and photocell with duct distortions more so with everclean windows
To be installed platforms not attached to duct.

4. DUST MONITORS Knowledge of dust emission as weight per unit volume
Got from dust samples
Continuous monitoring
Direct measurement on weight basis not given by instruments
Calibration done through dust samples and indication as a function of particle size
Particle size grading does not change (assumed)

5. DUST MONITORS - TYPES CERL flue dust monitor AEI flue dust monitor
Konitest flue dust monitor
SEROP flue dust monitor
FORDUST monitor

6. CERL flue dust monitor
Collects dust samples periodically and measures obscuration caused by this collection
A glass plate collects the dust and after measurement, dust blown away with compressed air
Favors larger particles, hence warns of emission likely to cause nuisance.
Recorder consists of circular chart with radial lines drawn proportional to dust.

7. AEI Flue dust monitor Withdraws a continuous sample of dusty gas
Given a swirl it results in electricity due to to friction
Measurement of this static electricity is a measure of dust

8. SEROP dust monitor Records light scattered by dust
An emitter beams light on to dust flow and scattered light collected by a photocell
No alignment problem
Scans larger volume
Free from corrosion as components are outside.