Rechargeable particulate filter for radioactive contaminated gas streams

In combination with a rechargeable gas filter of the type wherein a plurality of parallel laterally spaced vertically oriented generally parallelepiped filter beds are provided within a generally rectangular housing having a gas inlet and a gas outlet, wherein said beds each have two rectangular parallel vertical perforate walls for containing adsorbent material therebetween and having two vertical plates, one at the inlet side and the other at the outlet side, welded to said spaced perforate walls, two said vertical plates and two said perforate walls defining therein a single filter bed, said rectangular walls oriented with the sides of the rectangle vertical and horizontal, such that the bottom of the portion of the parallelepiped bed exposed to gas flow is flat and horizontal, and having vertically disposed channels welded between adjacent beds and between end beds and sides of said housing, alternately at the inlet and outlet, said vertical channels at the outlet defining gas inlet channels communicating with the inlet end of said housing and said vertical channels at the inlet thereby defining gas exhaust channels communicating with the outlet of the housing such that the spaces between adjacent filter beds alternately are inlet channels and exhaust channels whereby for gas to pass from an inlet channel to an exhaust channel gas must pass through the two spaced perforate parallel walls of a filter bed, wherein means connect said beds with one another and with said housing so that gas passing from said inlet to said outlet must pass laterally through said perforate walls of one bed and adsorbent material contained therein, the improved means for evacuating said filter of adsorbent material which comprises:

• a. a pair of longitudinally extending inwardly inclined funneling walls extending from bottom margins of adjacent filter beds entirely along the longitudinal length thereof, each wall of said pair extending downwardly and inwardly from an outer perforate wall of one of the adjacent filter beds, said pair of funneling walls forming a downwardly diverging discharge chute remote from the filter beds extending the length of the filter beds, said discharge chute being of greater length at one end of said filter beds and of lesser length at an opposite end of said filter beds;
• b. channel means laterally extending exterior of said discharge chute along the entire longitudinal length thereof;
• c. a well extending longitudinally the length of said discharge chute thereby encapsulating said discharge chute, secured to said channel means;
• d. a pipe extending in the longitudinal direction from the end of said well where said discharge chute is of greater length;
• and
• e. port means in the top of said housing for the introduction of adsorbent material to the filter therethrough;
• whereby when said filter is filled with granular adsorbent through said port means, granular adsorbent from said adjacent filter beds above said funneling walls will fall through said discharge chute and form a heap on the portion of said well below said discharge chute along the entire longitudinal length thereof until the angle of repose of the heap of particulate granular adsorbent closes the discharge chute;
• whereby when suction is applied to said pipe granular adsorbent in said well will be progressively drawn through said pipe, with granular adsorbent remote from said pipe in said well being drawn out first, such that all granular adsorbent in said adjacent filter beds above said funneling walls will be removed therefrom with the adsorbent in a corner of the parallelepiped most remote from the pipe being removed first.