US Patent 2,091,612, granted 31 August 1937 to René Picard of Vaulx en Velin, France, and assigned to E. I. du Pont de Nemours & Company. It describes a rotating-plug regulating valve placed in the pipeline between the pump and spinning nozzle of a viscose or similar artificial-thread spinning machine. The valve intermittently interrupts the flow of spinning solution, producing filaments of uneven denier with nubs or sharp thick-thin variations that imitate materials such as pongee silk. The document includes a drawing sheet (Figs. 1-6), the specification and a single claim.