| 摘要 |
Method for preventing fibre flocculations to occur and to disperse already formed fibre flocculations, better to distribute additive chemicals, to increase fibrillation, to improve reaction and yield from two component chemicals, to prevent the forming of microbiological and other types of build-ups onto machine parts and other parts of the white water circulations, to prevent the filling of wires and felts, to prevent flocculation in coating equipments, to reduce content of air in the stock, and to reduce the foaming. This is achieved by that ultrasonic energy with a frequency of 15 - 60 kHz is added to the stock, machine parts, washing trays or coaters via externally mounted ultrasonic transducers or internally applied submersible ultrasonic units. The ultrasonic energy is added preferably by means of externally onto the head box mounted ultrasonic transducers or internally applied submersible ultrasonic units. The level of ultrasonic energy is controlled by in-line installed formation or flocculation size measurement systems to arrive at desired flocculation. The measured flocculation is used as a criterium for set point optimisation of weight per unit area for the paper or the board produced, and for maximum production per unit of time. |
