Dust lamps

Airborne particulates include dust, fume and aerosols. Many such particles are invisible to the naked eye under normal lighting but are rendered visible, by reflection, when illuminated with a strong beam of light. This is the Tyndall effect and use of a dust lamp provides a simple technique for the rapid assessment of whether a dust is present, its flow pattern, leak sources, the effects of ventilation, etc. More sophisticated approaches are needed for quantitative data. Whether personal, spot or static sampling is adopted will depend upon the nature of the information required. 

MDHS 82 The dust lamp - A simple tool for observing the presence of airborne particles... 

Assessment and control of wood dust use of the dust lamp... 

HSE. The Dust Lamp—A Simple Tool for Observing the Presence of Airborne Particles. MDHS 82. London HMSO, 1997. 

This kind of spotlight enhances the visibility markedly and is very useful for the visualization of fine particles emitted from a relarively small source. Figure 12.2 illustrates the effect of a dust lamp used to visualize wood dust einissiori and exposure when sanding wood. 

Air flow patterns can be shown by tracers from smoke tubes which produce a plume of smoke when air is puffed through them (Figure 21.6). For workplaces where airborne particles are released it is possible to visualise the movement of the particles by use of a dust lamp. This shines a strong parallel beam of light through the dust cloud highlighting the particles in the same way that the sun s rays do. 

The Code of Practice lays down the tests to be carried out which include, for both Parts I and II, checks of pressures, velocities at various points and pressure differences across fans and filters. Part I tests should also include for sampling and dust lamp tests to check that the airborne asbestos is being controlled. Part II tests should, additionally, include a qualitative check using the dust lamp (Figure 29.2). 

A dust lamp is a very useful and versatile direct reading instrument. Many particles of dust are too small to be seen by the naked eye under normal lighting conditions but when a beam of strong light is passed... 

Tyndall (dust) lamp Figure 4.5.2) and/or fuming sulphuric acid test static pressure behind the captor hood. This is perhaps the most important test as this will determine whether the performance of the LEV equipment has altered ... 

LInknown broadband influences due to atmospheric aerosols, lamp fluctu ations, and dust on the mirrors are minimized by dividing the spectrum by a fitted fifth-order polynomial. The construction of the measuring instrumentation IS shown in Fig. 13.50. 

Tyndall lamp A parallel light beam pro jected onto a cloud of dust particles gen crated from a process to produce scattering of the light, allowing an assessment of the magnitude and path of the cloud. 

Clark La Motta (Ref 7) showed that LOX made with gas black or lamp black are more sensitive to impact than the standard Bureau of Mines 40% straight Dynamite. Impact sensitivity increased when small amounts of iron oxides, aluminum dust or ferro-silicon were added to the LOX. Impact sensitivity also increased as absorbent particle size was reduced. As the oxygen evapd, impact sensitivity, as expected, decreased... 

Coal Mines, Determination of Firedamp and of Coal Dust In Atmospheres of. Although many instruments have been designed to detect the presence of firedamp (or rather methane) in mine atmospheres, the principles of the flame safety lamp (Davy-type lamp) still form the basis of many detectors. The Davy lamp invented in 1815 is briefly described under COAL MINE EXPLOSIONS AND FIRES and it is stated that each US mine should have at least two Davy-type lamps to serve as detectors of firedamp or of lack of oxygen. If firedamp is present in small quantity, the flame of Davy lamp elongates and if the gas is present in considerable quantity, the lamp becomes filled with blue flame. For more definite detection of gas, the flame of the lamp is lowered until the yel part is at a minimum. Then the gas will be discernible as a small blue cap over the flame. This method is described in Refs 1, 9, 12 25. Some investigators consider that the safety lamp method of detection of firedamp is not very reliable (Ref 7)... 

Did you know that dust can explode Any flammable dust—for example, flour, sawdust, or grain dust—can explode under the correct conditions. The first recorded flour explosion occurred in an Italian flourmill in 1785. There were probably earlier explosions, but this is the first one ever recorded. In this case, a lamp in a bakery supposedly ignited the flour dust. Luckily, no one died in the explosion. 

Methane gas is found in pockets in the coal mines. The miners use a lamp for illumination and cut the coal seams using metal tools. Sometimes, the heat generated by this causes explosions in the mines. An explosion is always followed by the formation of carbon monoxide. Carbon monoxide is extremely poisonous when inhaled even in small quantities. This gas often prevents rescue work. Sometimes the mines are flooded, sometimes the roofs collapse trapping the miners. Miners continuously inhale the fine coal dust. This results in lung diseases. 

The substrate is heated under reflux with a drop of Hg in a quartz vessel illuminated with 254-nm light from a low-pressure Hg lamp until the desired degree of conversion has been achieved. The liquid product is poured from the mercury (dissolved Hg can be removed with Zn dust (excess, 1 h)) and the product is isolated by conventional distillation, chromatography, or crystallization, depending on the exact properties of the target compound. Yields from 85-95 % are typical. Details are given elsewhere [3-8]. 

A runway treated with GKZh will never be covered with ice. Water slides like mercury off its surface. Covering windshields of airplanes and automobiles with a thin layer of silicone liquid or varnish prevents ice and mist formation. Silicone compositions are used to cover lenses and optical glass to improve light permeability and resistance to atmospheric effects. Oligomethylsiloxanes are used for the outer covering of glass fluorescent lamps to keep dust off the surface. 

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