Abstract:
A method and an apparatus for measuring the amount (CW) of a coating (2) on a paper web (1). The amount (CA) of at least one component in the coating (2) on the paper web (1) is measured and the composition (CC) of the coating (2) to be transferred to the paper web (1) is determined. The amount (CW) of the coating (2) on the paper web (1) is determined on the basis of the amount (CA) of at least one component in the coating (2) on the paper web (1) and the composition (CC) of the coating (2) to be transferred to the paper web (1).
Abstract:
A method of controlling the quality and/or condition of a fibre web in a process for manufacturing and/or finishing the fibre web, which includes, monitoring the fibre web with at least one optical spectrum separating measurement device, determining a quality variable of the fibre web, measuring electromagnetic radiation reflected from the fibre web using an optical spectrum separating measurement device synchronously with a movement of the fibre web, and measurements in the form of spectral data, generating a continuous quality variable chart, dividing the continuous quality variable chart into successive matched partial charts having a cycle length, detecting deviations and/or discontinuities of the quality variable from the successive matched partial charts, and detecting malfunctioning of a rotating/moving means using the detected deviations and/or discontinuities of the quality variable.
Abstract:
The invention relates to a method in the process of manufacturing and/or finishing a fibre web, in which method said continuous and moving web, and/or a moving means related to the processing of the web, is monitored by at least one optical spectrum separating measurement device to determine at least one quality variable of said object for the purpose of controlling the quality or condition. According to the invention, spectral data is collected in synchronization with the movement from the object which is being examined and is in a progressive and/or rotating movement, by measuring electromagnetic radiation, which has been transmitted, reflected, or otherwise emitted by the object, in a temporally and spatially resolved manner. On the basis of this spectral data, a two-dimensional quality variable chart is formed, which is substantially continuous in the direction of movement of the object and presents at least one quality variable of the object, and in order to determine the characteristics of the object and/or to detect defects in the object from said continuous quality variable chart, local deviations and/or discontinuities are detected in said continuous quality variable chart, especially in the direction of movement. The cause of these deviations and/or discontinuities is identified on the basis of the periodicity of said phenomena in the direction of movement.
Abstract:
Optical radiation sources functioning on different optical bands radiate on different optical bands and focus optical radiation on a region in a web surface as pulses in such a manner that illumination areas of the pulses overlap on the plane of the web. At most one optical radiation band is focused on the web from the direction of the normal. The spatial intensity distribution of at least one optical band differs from the uniform distribution and the intensity distributions of at least two different optical bands differ from one another in a predetermined manner. A camera forms still images of the web surface region on each optical radiation band. An image-processing unit determines the surface topography of the web on the basis of the images. In addition, a controller may control the paper manufacturing process on the basis of the determined surface topography.
Abstract:
A method for the calibration of measuring equipment, and measuring equipment. The measuring equipment comprises at least one first sensor, at least one second sensor and at least one reference piece. When the measuring equipment is calibrated, a moving web is supported against the reference piece and the reference piece with the moving web supported thereto is moved to different distances from the first sensor and the second sensor. Further, a distance between the first sensor and the moving web and a distance between the second sensor and the reference piece is measured at least for two different distances, and the first sensor and the second sensor are calibrated to be uniform in relation to the movement of the reference piece.
Abstract:
A micro-optical grid structure is produced on a surface layer of a substrate by an embossing device and method. The embossing device includes an embossing member and a backing member, a temperature adjuster for adjusting the embossing temperature and a pressure adjuster for adjusting the pressure exerted by the embossing member and the backing member to the surface layer of the substrate. An optical measuring device is arranged to produce a diffraction signal dependent on the intensity of light diffracted from the surface of the substrate. The embossing pressure and/or temperature is/are adjusted on the basis of the diffraction signal to produce an optimal and even pattern depth of the grid structure. With the adjustment based on the diffraction signal, it is possible to avoid the sticking of the surface of the substrate to the embossing member due to too high an embossing temperature. When the pattern depth is optimal, collapse of the substrate caused by the too high embossing pressure is avoided.