Abstract: During the application of a coating material to paper or to cardboard, air inclusions in the coating material can interfere with production in various ways. It is proposed to measure the air inclusion content in a coating material by taking samples of the material. Each sample is introduced at a predetermined first pressure into a measurement cell which has a closed first volume. This closed first volume in then reduced to a closed second volume at which a predetermined second pressure that is greater than the first pressure prevails in the measurement cell. The air inclusion content of the coating material can then be derived from the change in volume required to produce the predetermined pressure change. On the basis of the measured values, degassing equipment can be optimally adjusted.

Abstract: An apparatus for automated polyelectrolyte measurement in process materials comprises a sample vessel with an outer wall defining a cylindrical cavity and with a reservoir of larger diameter above and in communication with the cavity. A liner for the cavity and the reservoir are made of an electrically insulating material such as polytetrafluoroethylene. To clean the apparatus there is also provided an ultrasonic oscillator which is mechanically coupled to the sample vessel. In order to improve the cleaning process, the liner and preferably also the reservoir are attached to the outer wall in such a way as to resist tensile and shear forces and the ultrasonic oscillator is attached to the outer wall. Preferably, the liner is attached to the outer wall by an adhesive.