Flow meter

In a production plant for a cellulosic fibre from wood pulp sheets with apparatus to measure the weight of wood pulp fed as input to the plant, the improvement which comprises using a basis weight scanner as a flow meter for determining the weight of bone dry wood pulp sheeting fed to the plant.

Apparatus for determining the weight of bone dry cellulose in a pluri-layer web of wood pulp sheets advancing towards a processing plant past a measuring location, which, at said measuring location includes a scanning head adapted to sweep across the entire width of the pluri-layer web in a direction transverse to its advance from edge to edge thereof, the scanning head including means to determine the moisture content of the web and generating a beam capable of being attenuated by the layers of wood pulp constituting the web and providing a beam-receiving means to determine, in real time, the degree of attenuation of the beam by the layers in the web, and computing means to determine from an aggregate of localized values of the attenuation and moisture content determined in one scan of the scanning head across the web, the total weight of bone dry cellulose in the sheet material passing the measuring location into the plant.

Apparatus for determining the weight of bone dry cellulose in a pluri-layer web of wood pulp sheet material advanced past a measuring location to a cellulosic fibre processing plant, which at said measuring location includes a scanning head adapted to sweep across the web in a direction transverse to its advance from a position outwardly of one edge of the web to a position outwardly of the other edge thereof, the scanning head comprising (a) means for generating a beam of electrons capable of being attenuated by the layers of wood pulp constituting the web disposed on one side of the web and a beam-receiving means disposed on the other side of the web to determine, in real time, the degree of attenuation of the electron beam by the web, and (b) a microwave source disposed on one side of the web and a microwave detector disposed on the other side of the web to determine the moisture content of the web and computing means to determine from an aggregate of localized values of the attenuation and moisture content determined in one scan of the scanning head across the web, the total weight of bone dry cellulose passing the measuring location.