摘要:
A method and apparatus for identifying a moving web in a paper making machine are disclosed. The method includes of the steps of illuminating the web with the light from a transmitter, reflecting the transmitted light off the web, receiving the reflected light with a light transducer to produce an electrical signal corresponding to the intensity of the received light, and identifying the moving web based on the received signal. The intensity of the transmitted light is adjusted so that the received light signal from the transducer is normalized with respect to an optimum value. The apparatus includes a light transmitter, a light receiver, and a control and identification circuit which identifies the web based on a signal from the light receiver, and which adjusts the intensity of the light transmitter to optimize the reception of the signal from the light receiver in order to minimize the effects of environmental interference.
摘要:
Method and device for monitoring a moving web, such as a wire in a paper machine, a felt, or a material web, such as a board or paper web. A bar of radiation beams is directed at the face of the web to be monitored by a series of transmitters in a direction transverse to the direction of movement of the web. Radiation reflected from the web and the background is detected by a series of receivers. The measurement signals obtained in this way are passed to an electronic unit in which a quantity that characterizes the monitoring of the web is determined from the measurement signals. The approximate location of the edge, the edges, or of corresponding discontinuities of the web is detected "digitally" on the basis of the radiation beam of the radiation transmitter in whose area the greatest change takes place in the received radiation. The precise location of the edge or equivalent of the web to be monitored is determined analogously by comparing the amplitudes of the signals of the adjacent receivers placed closest to the last-mentioned radiation transmitter with one another.
摘要:
In a tissue machine, a roll is arranged to press a paper web against a Yankee cylinder. A steam box is arranged in connection with the roll. A steaming area of the steam box is arranged against the paper web substantially above the horizontal center line of the roll.
摘要:
A method for blowing steam against a paper web, whereby the steam is blown by a steam box having several profiling chambers in the cross direction of a paper machine. The cross-profile of the paper web is controlled by the steam supplied by the profiling chambers. A gas flow is provided between the profiling chambers to prevent the steam blown by a profiling chamber from affecting the effective area of the steam blown by the adjacent profiling chamber. Further, a steam box for implementing the method is disclosed.
摘要:
A steam box in a paper machine, the steam box including a main steam zone and at least one side steam zone through which steam is blown to a paper web. The side steam zone is placed in a side section of the steam box and arranged to form a curtain in order to prevent air from entering between the steam box and the paper web from outside the steam box and/or to prevent steam from exiting between the steam box and the paper web. Steam is supplied to the side steam zone from a steam chamber through a side steam zone valve arranged inside the steam box.