Twin wire former in which drainage starts above a forming roll wrapped by two wires and continues between two rows of blades.
Definition source:
Brewer (2003)
Context:
The roll-blade former was developed in an attempt to combine the advantages of the two basic designs, and this approach has met with great success. Drainage starts at the forming roll wrapped by the two wires, but with a lower wrap than on a typical roll former. In this way fiber layers are formed on both wires. These layers prevent washing out of fines and filler during the subsequent pulsed drainage where the fabrics pass alternately between two rows of blades. On some newer designs, the blades on one side are fixed, while those on the opposite side are adjustable to provide better control of the pulse amplitude at each position.
