Polyvalor S.e.c.

Macmillan Bloedel Limted

Pevifibe Papers Inc.

Olivier Reglat

Philippe Andre Tanguy

Malcolm Kenneth Smith

David Richard Elvidge

Fran&ccedil;ois Bertrand

Alfa Arzate

The apparatus ( ) is used for determining the consistency index (k) and the power law index (n) of a Newtonian fluid or non-Newtonian power law fluid. A method is also disclosed. Accordingly, the fluid flows in a laminar manner through a first ( ) and a second static mixer ( ) successively connected together by means of an intermediary pipe ( ). A first pressure differential (&Dgr;P ) corresponding to a pressure drop of the fluid through the first static mixer ( ) is measured. Similarly, a second pressure differential (&Dgr;P ) corresponding to a pressure drop of the fluid through the second static mixer ( ) is measured. Finally, the consistency index (k) and the power law index (n) are calculated using the Metzner and Otto concept generalized to static mixers. The apparent viscosity may also be calculated. This invention may be mounted directly on a main supply pipe ( ) and allows the rheological properties of the fluid to be known in real time. It also improves the mixing of the fluid and maintains its homogeneity.

Apparatus and method for measuring the rheological properties of a power law fluid

The system and the method are used to determine the process viscosity (&mgr;) of a fluid ( ) in a film metering device ( ) used to form a film ( ) to be applied on a substrate ( ), such as a paper web or any other suitable flexible materials. The apparent shear rate ({dot over (&ggr;)}) of the fluid, indicative of the flow field, may also be calculated. These parameters are calculated using a pressure profile representing the pressure of the fluid between a transfer roll ( ) and a metering rod ( ) which controls the thickness of the coating film ( ). The torque (T) applied on the metering rod ( ) is also measured and taken into account in the calculations. The system and method allow the process viscosity (&mgr;) to be easily and accurately determined during the operation of the film metering device ( ) without the need of testing the fluid in an external device and attempting to extrapolate the results to the process.

System and method for determining the process viscosity of a fluid in a film metering device

A coater head for applying coating to a size press roll of a size press coater, the coater head has a flow passage with a metering device at its outlet end and a metering chamber immediately adjacent to the metering end. A shear developing passage delivers coating to the metering chamber and a mixing passage leading into the metering chamber mixes fresh coating with return coating on the surface of the roll to carry the fresh coating to the outlet end of the metering chamber. The metering chamber is dimensioned to form a stable vortex within the chamber thereby to improve the uniformity of the coating wet film.

Coater head

A pilot coater for applying a coating on a moving web sample is formed by a backup roll, a transfer roll and a coating flow metering system metering coating flow onto the transfer roll. A pneumatic actuating system holds the transfer roll in a ready position until a sensor detects a specific portion of the web is moving into a nip found between the backing roll and transfer roll and triggers movement of the transfer roll and coating metering system to move to a coating position with the transfer roll pressed onto the paper supported on the backing roll. After a preselected period of time, the transfer roll is moved from the paper to terminate the coating operation.

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Montreal, Canada

Olivier Reglat