or red light respectively to indicate go no go conditions an advantage of this modular construction is that either the power supply in housing part 24 or the filter in housing part 22 may be replaced or returned to the manufacturer for maintenance also as the system is improved either the filter part 22 or the power supply part 24 may be upgraded with a newer design the internal construction of the filter housing part is shown in fig2 inside housing part 22 molded cleats or ribs 48 are formed periodically along the length of the interior housing walls the dimensions are such that a plurality of perforated electrostatic plates 50 52 may be inserted into and supported by tracks formed by the ribs 48 these plates are uniformly perforated across their entire surface a few of the perforations being shown in the drawings and labeled 34 p1 34 the end spaces 54 56 are empty to collect water a similar foreign fluid or the like which may be entrained in the fluid being processed two conductive bars 26 28 extend throughout substantially the full length of the housing part 22 and on into jacks 27 29 which are energized by the power pack in housing part 24 one of the bars here 28 is at a positive voltage the other of the bars here 26 is at a negative earth ground potential this means that bar 28 is at one of the positive potentials 5 000 10.