Infilco Degremont, Inc.

William R Nichols

Improved methods are disclosed for cleansing a plurality of seriate filter beds in automatic backwash filtering systems by backwashing the beds one at a time with backwash liquid from an effluent channel common to seriate effluent ports of the plurality of filter beds and pumping the backwash liquid seriatim through separate effluent ports of individual filter beds and then flowing filtered effluent from each bed through its effluent port into the effluent channel, repeating such steps of backwashing and flowing filtered effluent on individual filter beds until all the filter beds in the system have been backwashed wherein, simultaneously with the backwashing of a second bed, waste liquid from the first bed is pumped through its port while the waste liquid is monitored for turbidity and such waste liquid pumping is continued until the turbidity thereof reaches a predetermined low level. Meanwhile, the cleansing operation on the second bed is prevented from moving to a third bed until the turbidity of the waste liquid from the first bed reaches the predetermined low level. Such monitor control operation is applied to third and further ports until all filter beds in the system have been cleansed.

Method for monitoring turbidity of waste liquid in backwashing filter

Apparatus for sequentially backwashing a plurality of seriate filter beds

Automatic backwash filter systems including a filter tank divided into a multiplicity of seriate cells of substantially the same width by a plurality of vertical rectangular cell sheets are improved by provision of new spacer assemblies to mitigate bowing of the cell sheets during backwashing or other operations applied to the cells. Such spacer assemblies include horizontally aligned bores that extend through each cell sheet adjacent their top, one or more stringers that extend through the bores, and a plurality of tubes of approximately the same length substantially equal to the width of the cells. One of such tubes is positioned in each filter cell surrounding the stringer present in such cell and between the surfaces of the respective cell sheets. Where a plurality of stringers are used in the spacer assemblies arrangements are disclosed for making final connections to complete the assemblies.

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Richmond, VA, United States of America

William R Nichols