Abstract: In a heat treatment apparatus for bobbins of yarn having a plurality of heat treatment baths arranged between a spinning machine and a winding machine, the bobbins from the spinning machine are carried into the heat treatment baths by a conveyor line with pegs, the heat treatment is performed in the baths with the bobbins mounted on the pegs, and the heat-treated bobbins are automatically delivered from the baths onto another conveyor line with pegs installed on the winding machine side.

Abstract: In filtering a tar mist-containing gas to remove the tar, a filter bag having an inner surface and an outer surface is coated with a tar absorbent powder by feeding the powder into the top of the bag for free-fall therethrough while maintaining a slightly reduced pressure outside the bag to deposit the powder on the inner surface of the bag and then feeding the tar mist-containing gas into the filter bag while maintaining a greatly reduced pressure outside the filter bag to collect a layer of tar on the coating, and thereafter stripping the powder containing the absorbed tar from the inner surface of the filter bag.