GB1411346A - Devices for eliminating the expansion effect in a bed of granular material - Google Patents

Abstract

1411346 Ion exchange DEGREMONT SOC GENERALE D'EPURATION ET D'ASSAINISSEMENT 2 July 1973 [4 July 1972] 31409/73 Heading B1J A device for eliminating the expansion effect during backwashing or regeneration in a bed of granular material, such as a bed of ion exchange resins, through which an upwardly moving stream of backwashing or regenerating liquid is moving, comprises means for maintaining air at atmospheric pressure above said bed; means for introducing said liquid into the bottom of said bed and passing said liquid upwardly therethrough; and means for discharging said liquid from said bed and for maintaining the upper level of said liquid at a predetermined height below the upper surface of said bed without upwardly expanding said bed, said means for discharging and maintaining comprising: a header having attached thereto a purality of vertical pipes positioned within said bed below said upper surface thereof; vacuum means connected to said header to withdraw said liquid from said bed; and vertical slot means in each of said vertical pipes for allowing varying amounts of air from above said bed and of said liquid to pass to said header dependent upon variations in de mand, and to thereby maintain said upper liquid level at said predetermined height below said upper surface of said bed and to avoid upward expansion of said bed. As shown, liquid to be treated enters the apparatus at 9 and leaves at 13, alternatively, regenerant enters at 13 and leaves at 18. The header 18 has a number of dependent pipes 20 each having a slot 28 (Fig 2). For regeneration, vacuum is created by ejector 23 which draws off liquid down to the level of the slots. Regenerant is then admitted at 13, passes upwards and is withdrawn through the slots.