to the head 74 in any convenient manner and supports filter 78 which forms an extension of the filter head 74 and preferably is annular in shape the housing 76 is preferably connected to the filter head by way of a bolt 80 threaded to the extension 82 the filter head 74 has a flow passage 84 communicating at its upper end with the tube 68 passage 84 communicates at its lower end with the interior of the filter 78 by way of a plurality of flow passages 86 see fig4 and 5 the upper end of the tube 68 communicates with a right angle flow pasage 88 in the distributor head 66 a tube connector 90 has one end connected to the distributor head 66 and its other end connected to one end of a flexible withdrawal tube 92 tube 92 communicates with the interior of the vessel 40 by way of connector 90 passage 88 tube 68 passages 84 and 86 and filter 78 the upper end of tube 92 is connected to one end of a conduit 96 by way of a connector 94 supported by the insert 46 due to the fact that the agitator 51 orbits but does not rotate tube 92 does not wrap around the agitator 51 during operation referring.