formed by the outer braided cover of the filter or extractor elements and this liquid will be drawn into the recirculating loop and deposited into the dirty portion of the process liquid storage tank the level of liquid in the vessel will drop as the liquid is extracted by the extended elongated flexible filter elements 120 as the level of liquid drops the concentration of particulate matter to liquid will of course increase however as long as the particulate matter is sufficiently wet so as to be movable in suspension the extracting action induced by the suction in the flexible filter tubes will still act as the level of liquid drops below the bottom of the front wall 70 of vessel 61 the lack of liquid will cause the particulate matter to form a cake around the elongated flexible filter or extractor tubes 120 and this cake will prevent the direct of access of air into the filter tubes 120 which would substantially diminish the vacuum in the manifold the lower portion of the vessel namely that portion nearer the manifold 80 would still contain liquid and the portions of the elongated flexible filter tubes 120 located in the still wet areas would still continue to extract liquid from.