Conduit system for conveying fibrous stock from deaerator chamber to headbox in papermaking machine

In papermaking apparatus comprising

• papermaking stock receiver means defining an enclosed evacuated chamber having a collecting zone for deaerated aqueous supply stock, and evacuating means associated with said chamber for maintaining its collecting zone under a vacuum sufficient to deaerate aqueous papermaking stock introduced therein,
• means for introducing aqueous papermaking stock into the collecting zone of said chamber in a manner facilitating deaeration thereof to produce deaerated supply stock therein,
• a papermaking machine including a forming wire for converting deaerated supply stock into a web of paper, and structure associated with said papermaking machine having an interior delivery passage provided with an exit slot for delivery therefrom in the direction of the papermaking machine axis of an effluent jet of stock onto said wire for conversion into a paper web upon removal of liquid therefrom, the improvement which comprises
• dropleg supply conduit means defining a flow course communicating said papermaking machine associated structure delivery passage and its exit slot to a bottom portion of the evacuated chamber collecting zone through which deaerated supply stock can be conveyed from said collecting zone to said papermaking machine and comprising a plurality of separate pipes, said pipes being parallel to each other and to said machine axis,
• said separate pipes each having a longitudinal through flow passage with upper entry ends thereof being connected to said collecting zone bottom portion and arranged in closely spaced array with respect to each other along a substantial part of a major lateral expanse of said collecting zone bottom portion, lower exit ends of said separate pipes being connected with said papermaking machine associated structure delivery passage along a relatively wide course extending transversely of said delivery passage, and being arranged in closely spaced array with respect to each other extending transversely in the direction of the transverse length of said exit slot, the flow course of said pipes between entry thereto and exit therefrom having no flow course deviation therein extending laterally of the axis of the papermaking machine, said receiver means being elevated above said exit slot a sufficient height to overcome the effect of vacuum on gravity outflow of stock from said receiver means, said distance of elevation being additionally such as to provide a stock pressure head sufficient to overcome flow frictional losses in said pipes and said papermaking machine associated structure delivery passage and its exit slot, and flow control means associated with each of said pipes for regulating the rate of flow of deaerated stock therethrough from said chamber collecting zone to said exit sot.