A thermal precipitator for the gravimetric estimation of solid particles in flue gases

The instrument described is designed to collect all the solid matter from a representative sample of flue gases, and to handle a sufficiently large sample of gas for the deposit to be easily weighed. Its advantage over the usual filtering methods are that it does not offer excessive resistance to the gas flow, and that it is apparently capable of retaining the smallest size of particle present in flue gases. In addition, the use of aluminium foil collecting surfaces facilitates accurate weighing, since, unlike the usual filtering materials, their capacity for adsorbing moisture is negligible.