Abstract: A method of controlling the properties of a paper web across the feed direction, i.e., cross profile, in a paper machine. The cross profile is adjusted in a plurality of setting positions across the web. Proceeding from a measured cross profile and desired cross profile, an optimum correction in the setting positions is calculated, so that the cross profile is brought into agreement with the desired one. At this calculation the circumstance is utilized, such that a disturbance in the stock in a certain setting position results in a corresponding change in the cross profile of the paper web.

Abstract: Web tension measurement in that the web (5) is caused to oscillate transversely with the resonance frequency for the portion of the web (5) defined by a support (2,2a). The oscillations are measured by detectors (6,7) for determining the web tension. The measuring is carried out free of contact in that a thin air layer is maintained between the support (2,2a) and web (5).

Abstract: Fiber content measuring instruments having radiation detectors are used to indicate the average radius and/or the average length of particles in a flowing medium. In order to determine the average radius, a signal based on the alternating current voltage portion of the signal from a radiation detector having a high resolution is divided by a signal based on the direct current voltage portion and the signal from a radiation detector having the same or another resolution. In order to determine the average length a signal based on the alternating current voltage portion of the signal from the radiation detector having a low resolution is divided by a signal based on the alternating current voltage portion of the signal from the radiation detector having a high resolution.

Abstract: Methods of measuring the crill content of pulp suspensions are disclosed. The methods include passing a first light radiation, preferably ultraviolet light, having a wavelength comparable to the particle diameter of the crill, through the pulp suspension, passing a second light radiation having a wavelength longer than the first wavelength but shorter than the mean pulp diameter through the pulp suspension, collecting both light radiations after they have transilluminated the pulp suspension, and measuring absorbencies for both of these collected light radiations so that the crill content can be determined therefrom.

Abstract: A method and apparatus is provided for measuring the ratio between web tension and web substance by causing the web to vibrate at its resonance frequency, measuring the pressure variations or the signal causing the web vibration to produce a first signal, measuring a signal in phase and representative of the vibration of the web and to produce a second signal, comparing the phase difference of the first and second signals so that a deviation from a predetermined phase difference produces an output signal, and controlling the frequency of the signal or pressure variations causing the web to vibrate in response to the output signal so that the predetermined phase difference is maintained.