Patent ID: 7117595

Claim:
A method for manufacturing a conveying element for an axial type flow meter comprising an impeller ( 46 ) having at least a blade ( 46 A) extending from a hub ( 46 B) to which a rotation pin ( 46 C) is associated, and a conveying element ( 41 ) having a central core ( 42 ), a peripheral part ( 43 ) and one or more blades ( 45 A, 45 B) with a helical surface developing with at least a complete coil around said core ( 42 ), where the conveying element ( 41 ) has a profile and is made as one piece by molding a thermoplastic material, comprising the following steps: providing a molding element ( 60 , 70 ) defining an impression ( 61 , 71 ) for the formation of at least a part of the profile of the conveying element ( 41 ), said impression ( 61 , 71 ) forming a cavity; providing a male ( 75 – 76 ) comprising one or more spiral plates ( 75 , 76 ); positioning of said male ( 75 – 76 ) in said cavity through a corresponding injection opening ( 72 ); injection of a fluid thermoplastic material into said cavity through said corresponding injection opening to form the conveying element therein; removal, after setting of the thermoplastic material, of the male ( 75 – 76 ) from said cavity, by substantially unscrewing the male from the conveying element thus formed and moving the male backwards away from said cavity; extraction of the conveying element ( 41 ) thus formed from the molding element ( 60 , 70 ).