摘要:
Properties of paper are controlled by modeling the effect of at least one variable (fD) of the paper dryer section on the paper moisture (Moi) and the effect of the stock flow (Fts) and/or stock composition and the flow of retention agent (Fra) on the paper moisture (Moi). By means of the modeling, the paper moisture (Moi) is adjusted by simultaneously controlling at least one variable (fD) of the paper dryer section, the stock flow (Fts) and the flow of retention agent (Fra).
摘要:
Method for regulating a basis weight of a paper or cardboard web in the manufacturing process. The method includes determining a basis weight at an end of the manufacturing process, calculating a deviation of the determined basis weight from a predetermined target value, adjusting a concentration of a material suspension supplied to a headbox via a first control loop such that the calculated deviation is corrected, one of directly and indirectly measuring a basis weight of a resulting web in a region upstream, with regard to a web travel direction, a drying section, and supplying a signal related to the measured basis weight to a second control loop.
摘要:
The invention concerns the short circulation of a paper or board machine and in particular a simplified process arrangement for the short circulation, which arrangement comprises a metering system (20) for the stock (M) or stocks, pumps (110, 130, 170), a headbox (150), and a wire part (160) as well as a pipe system interconnecting the devices, with means of regulation, and in which arrangement a high-consistency stock (3) is fed into the headbox (150), and the white water (4) recovered from the wire part (160) is fed by means of a diluting pump (170) into the headbox (150) so that diluting of the stock suspension is carried out in the headbox.
摘要:
A sample collecting device takes samples from the white water drained from the web through the wire in the wire part, at a number of points in the cross direction of the web. An analyzer analyses the samples and forms a retention profile for controlling the paper machine. The device for measurement and regulation of the retention profile comprises means for measurement of the retention profile across the web width from different points of width of the web. The headbox comprises ducts passing to different points of width of the headbox to pass a flow of liquid containing a retention agent in the headbox into connection with the stock flow to regulate the retention profile across the web width. The ducts have valves which are regulated on the basis of the retention profile data for regulating the retention agent into duct flow.
摘要:
A method of selecting bulk wood units for mechanical pulping, which consists of establishing a reference scale by selecting a test sample measuring the acoustic velocity through each sample unit, selecting acoustic velocity band from the sample results, processing the sample units using known mechanical pulping processes, testing the resulting pulp to measure the freeness of the pulp, and then graphing the pulping energy measurements against the pulp freeness measurements for each of the velocity bands to produce a reference scale; measuring the acoustic velocity through each of the units, comparing the velocity measurement for each unit against the reference scale, and then dividing the tested units into subgroups according to the predicted mechanical pulping energy.
摘要:
Method and apparatus for controlling the mixing proportions of feed streams being supplied to a headbox, using devices for sampling two or more of the feed streams upstream of the headbox and devices for measuring concentration of constituents in or other properties of those samples. A method of regulating one or more properties of a moving web, and especially a paper web during manufacture, employing the aforesaid method and apparatus are also disclosed.
摘要:
The present invention relates to a method for producing and testing a fiber bed (39), includes a housing (12), a main inlet passage (14) and a main outlet passage (16), a cavity (18) in said housing in fluid connection with said inlet and outlet passages, a body (20) rotatably arranged in said cavity, said body being arranged with a through-going passage (24) having a first and a second opening, a screen (25) arranged in said through-going passage, and means (40) for measuring properties of the fiber bed. The method is characterised in positioning said body so that the first opening is connected to the main inlet and the second opening is connected to the main outlet, creating a first passage, leading a fiber suspension through the first passage in order to produce a fiber bed on the screen, measuring the properties of the bed, rotating said body such that the second opening is connected to the main inlet and the first opening is connected to the main outlet and creating a flow through the first passage for removing said fiber bed from the screen through the outlet. The present invention also relates to a device for performing the method of the invention.
摘要:
A method for applying a foam to a paper web is provided. Specifically, a foam is first formed from a liquid-based composition and a gas, such as air. Once formed, the foam is applied by a foam applicator to the web. In one embodiment, for example, the foam applicator applies the foam without substantially contacting the web. When applied with the foam, the web typically has a solids consistency less than about 95% by weight of the web. In some embodiments, one or more vacuum slots can be utilized in conjunction with the foam applicator to facilitate uniform application of the foam to the paper web.
摘要:
A multi-layer headbox for a paper or board machine including stock inlet headers each providing one stock and coupled to a tube bank which in turn is coupled to a respective intermediate chamber. The stock flows from the intermediate chambers into a turbulence generator and through pipes in the turbulence generator into a slice cone to be discharged therefrom onto a forming wire. The multi-layer headbox includes distribution valves for regulating the flow of dilution water across the width of the headbox. Each distribution valve communicates with a distribution plate placed in connection with the tube bank. From each valve, the dilution liquid is distributed at the same time to all the stocks that form the different layers of the web in the multi-layer headbox at a specific position of width of the multi-layer headbox.