very good results are achieved with the roll blade former for example with a view to sheet formation within an optimum operating window af opt which is defined by the following terminating straight lines throughput d s with the terminating straight lines at 15 000 1 min u00b7 m and 18 380 1 min u00b7 m and forming shoe dewatering e f at 1 300 1 min u00b7 m and 1 800 1 min u00b7 m 0054 fig6 illustrates an enlarged version of the optimum operating window af opt whereby the operating point ap is in the optimum operating window af opt on product changes the operating point ap leaves the optimum operating window af opt vertical down arrow and is placed on the curve k u2032 broken line outside the operating window a f providing poorer results with the known and aforementioned twin wire formers the fiber suspension throughput d s through the headbox must then be increased in a negative way upward arrow angled toward right in order to return to the optimum operating window in summary it can be said that the present invention of a twin wire former provides that the aforementioned disadvantages of the state of the art are completely avoided and that fiber suspensions containing long fibers which are particularly difficult to form for example papers can be put to optimum use while this invention has been described as having a preferred design the present invention can be further modified within the spirit and scope of this disclosure this application is therefore intended to cover any variations uses or adaptations of the invention using its general principles further this application.