25 are shown with relation to one of the springs 41 located at the side of the replendam 25 the first leg 86 of the spring 41 extends to the reticulated wall 80 and the second leg 88 extends to the inner support frame 89 a short lateral support member 92 connects the inner support frame 89 to the outer frame 95 as described above the outer frame 95 conforms to the six sided shape of the sorbent bed 16 the outer frame 95 is formed with the v shaped rib 50 on the bottom and with the v shaped groove 53 on the top in fig1 16 the cover 19 is shown in greater detail the cover 19 has a complex shape with a round section 110 extending outward from a six sided planar section 113 the round section 110 corresponds to the shape of round filter media 13 other shapes for section 110 for use with non round filters would also be suitable the six sided planar section 113 terminates in side walls 115 that extend substantially perpendicular to the planar section 113 in fig1 the opening 24 is covered by the grill or reticulated wall 23 the round filter media 13 fig4 is potted in the round section 110 by applying a glue 111 best shown in fig4 to the perimeter of the filter media 13 such that a r is prevented from passing around the edges of the filter media 13 between the media 13 and the inner wall of the cover 19 as shown in fig4 the air dam 83 acts as a adhesive barrier to prevent glue from entering the plenum chamber 40 in fig1 the hook 68 and the first and second v shaped ribs 56 59 are.