摘要:
The invention relates to a method for dealing with faults occurring during the calendering of a material web, said method comprising at least the following steps of: -identifying the location of a fault (H) on the surface of a roll (5) or in a material web and estimating or calculating an arrival time of the fault (H) at a roll nip (N) and a dwell time for the fault in the roll nip, -transmitting from a control system (4) to at least one digital valve unit (100), used for controlling a nip pressure of the roll nip (N), a feed-forward adjustment instruction (F) for dealing with a fault in the roll nip (N) of a calender, -reducing as per adjustment instruction (F), through the intermediary of at least one digital valve (1), a nip pressure of the roll nip (N) at the latest when the fault (H) arrives at the roll nip (N) and increasing the nip pressure as the fault exits the roll nip.
摘要:
The invention relates to a processing device and a method applying the same for processing a coated or uncoated fibrous web. The device comprises a belt (2) adapted to extend around a guiding element (3), at least one counter-element (5) being disposed outside said belt to provide a contact area with the belt, such that the belt (2) and the counter-element (5) establish therebetween a web processing zone for passing a web to be processed therethrough. The processing zone length is defined by means of the disposition of the belt's (2) guiding element (3) and/or by means of the design of the counter-elements (5). The contact pressure applied to a web in the processing zone is adapted to be adjustable within the range of about 0.01 MPa to about 200 MPa. The invention further relates to a method for switching paper, board or tissue from one grade to another, where the adjustment of the temperature applied to the web is essentially performed only by means of the adjustment of the metal belt temperature, a mechanism for the adjustment of a belt-tension inflicted compression force, a device for controlling and profiling the lateral tension and/or temperature of the belt, a processing device where the metal belt loop os adpated to run in an enclosed or isolated space and a processing device where the position of the belt in lateral direction is adjusted.
摘要:
The object of the invention is a control and an adjustment method for the fibre web machine. According to the invention -an emitting voice is measured continuously at least from one section of the fibre web machine and frequency bands (df) and/or the combinations of the frequency bands and amplitudes of the same, which correlate state and change of different process values, are separated measuring signals (fm); - the measuring signals are compared with reference signals (fref), which correlate an ideal state or a desired state; and - control signals are generated from deviations of the measuring signals and reference signal (fA), by which control signals the measured process values are returned closer to the ideal state or the desired state.
摘要:
The invention relates to a method for treating a fibrous web downstream of slitting. In the method, the finishing of a fibrous web for providing desired properties is performed by using one or more finishing units, at least one of which comprises a web processing apparatus provided with a metal belt.
摘要:
The invention relates to a fibrous web processing apparatus with a metal belt loop for different uses in a paper/board machine, the processing apparatus comprising a metal belt (2) rotating around at least one guide means (3). The ratio of the length of the metal belt (2) to its width is greater than 0.8 and more preferably more than 1.
摘要:
A method for producing calendered paper by an on-line manufacturing system comprising at least a paper machine and a multi-nip calender. The method comprises following steps; removing water from a formed paper web by pressing, drying the pressed paper web by at least one dryer, calendering the dried web by the multi-nip calender, measuring a cross machine moisture profile or a variable relative thereto, and altering the moisture of the web so that the moisture profile of the web in cross direction is even when the web enters the first nip of the calender.
摘要:
The invention relates to a nip roll of a paper or board machine, the roll being a heatable roll manufactured of steel. The thermal shock resistance of the roll is over 6000 W/m2.
摘要:
A drive device is proposed which comprises a roll (10) for transporting material, and a variable reluctance motor including a stator (20) and a rotor (10a), said rotor comprising salient poles (30), wherein the roll comprises a shaft part (10b) and the rotor.
摘要:
The invention relates to a digital hydraulic controller (2) comprising at least two rows of valve elements, one of said rows of valve elements being adapted to connect a supply conduit to a controller outlet and the other row of valve elements being adapted to connect the controller outlet to an outlet conduit. The valve elements of every row of valve elements are connected in parallel in the controller (2) and can be switched simultaneously either individually or in various combinations thereof. Each valve element of a row of valve elements has a different flow cross-section. The valve element which has the smallest flow cross-section is present in the row of valve elements twice. The invention further relates to a system unit comprising a differential cylinder (1) and a digital hydraulic controller (2) which has four rows of valve elements, two of which are connected to one pressure chamber of the differential cylinder with their common controller outlet while the other two rows of valve elements are connected to the other pressure chamber of the differential cylinder (1) with their common controller outlet. Due to the fact that the pressure in the two pressure chambers can be independently set, the differential cylinder can be used as a linear actuator that can be precisely set.