GAS FILTER

摘要

A gas filter particularly a room air filter which comprises a square frame and an interchangeable filter package which includes a gas entrance and a gas discharge port and contains a filter web with a zig-zag configuration for forming a plurality of proximate filter pockets. The filter web is secured between encircling walls and further comprises a support grid for receiving the same which is mounted in the frame and which has a shape complementary to the folds of the filter web which is characterized in that all encircling walls of the filter package have a stiff constructions and together form a rigid container, the gas entrance port thereof is adapted to be closed by bending in and folding over the marginal strip of the encircling walls which is adjacent to the port, and that the folds adjacent to said gas discharge port are held by tension means which extend in the direction of the folds and are anchored in opposing encircling walls.