Winding – tensioning – or guiding – Convolute winding of material – With particular material connection to take-up
Reexamination Certificate
1999-10-21
2001-12-25
Nguyen, John Q. (Department: 3653)
Winding, tensioning, or guiding
Convolute winding of material
With particular material connection to take-up
C242S526000, C242S534000, C242S541000
Reexamination Certificate
active
06332587
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for threading a material web onto a reel, e.g., in a paper machine, The being of the material web to be threaded is guided around a drum that precedes the reel and, before being threaded onto the reel, is supplied to a preparation station, e.g., a pulper. The invention also relates to a device for performing such a process.
2. Discussion of Background Information
Threading of a material web onto a reel is required, for example, at the beginning of a winding process to wind a beginning of the web onto an empty reel. Likewise, a threading process is required in the event of a web break to thread a new web beginning onto either a wound reel or an empty reel. For this purpose, the empty reel or the wound reel is placed onto the drum after the previously wound reel has been removed.
Before the beginning of the web is threaded, it is supplied to a pulper in which the threading tip of the material web is removed. The threading tip is thus discarded into the pulper immediately after being guided around the drum that precedes the reel. After the material web has widened out with its continuous disposal of it into the pulper, the material web is cut and only then is it threaded onto the empty or wound reel,
One problem with the above-noted process is that the material web threads itself onto the reel before being cut. This problem occurs to a greater extent at high machine speeds.
Attempts have been made to solve this problem by embodying the drum preceding the reel as a suction drum, which produces a negative pressure within the drum that acts on the material web through corresponding openings in the drum to secure the material web against the drum. However, this arrangement can, to a large extent, prevent a self-threading of the material web onto the wound reel or the empty reel. Moreover, the negative pressure inside the drum makes it more difficult to remove the web for disposal into the pulper.
SUMMARY OF THE INVENTION
The present invention provides a process of the type generally discussed above, in which self-threading of the material web onto either a empty reel or a wound reel is prevented, to the greatest extent possible, without complicating the removal of the web from the drum preceding the reel. In addition, a suitable device for performing this process is disclosed
Therefore, before being threaded onto the reel, the material web can be kept away from the reel via blower air,
A device for performing the above-noted process can include a blower bar arranged cross-wise (laterally) to the web travel direction and having at least one exit opening for the blower air, a device for supplying blower air to the blower bar, and a control unit for controlling introduction of the blower air,
By keeping the material web away from the wound reel or the empty reel via blower air, self-threading of the material web onto the wound reel or the empty reel can be effectively prevented without necessitating suction to the drum preceding the reel. In this manner, removal of the web from the drum can be facilitated, even though the blower air does not significantly influence the web removal.
The empty reel that is placed onto the drum or the wound reel that is pressed against the drum is acted upon with blower air that is directed counter to the web travel direction and downstream of a contact line of the drum and reel. Therefore, the blower air forms a type of air knife, which cuts between the material web and the empty reel or the wound reel to prevent the material web from self-threading onto the empty reel or the wound reel. It can be advantageous if the blower air is introduced at a flat angle, e.g., between approximately 15° and 45°, and preferably between approximately 20° and 35°, onto a circumferential surface of the empty reel or the wound reel.
According to another embodiment of the invention, the blower air can at least intermittently introduced across an entire width of the material web. This embodiment can prevent self-threading and the material web may be conveyed away from the empty reel or the wound reel in a continuous fashion.
According to another embodiment of the invention, the blower air may be at least intermittently introduced only in a partial region of the material web, e.g., in a vicinity of a threading tip. This arrangement can save blower air without increasing the danger of self-treading and without impairing the guidance of the material web.
According to another embodiment of the invention, the blower air can be automatically activated in a threading process, which can simplify the operation of the device. It may be preferable for the blower air to be activated in a time-delayed fashion at the beginning of the threading process, which can in turn result in a savings of blower air.
According to another embodiment of the invention, the blower air may be activated by a break control, e.g., in the event of a web a break, which can simplify the activation of the blower air.
According to another embodiment of the invention, the blower air may be introduced at a predetermined distance. The distance can be preferably set by at least one distance sensor. The action of the blower air can advantageously be adapted to the respective conditions by adjustment of the predetermined distance. For example, the condition of the material web and the web travel speed can be taken into account.
The use of a blower bar for performing the process according to the invention can be structurally inexpensive and at the same time particularly effective. Due to the ability of the blower bar to be moved between a blowing position, in which the blower bar is disposed particularly near the circumferential surface of the empty reel or the wound reel, and a retracted position, a suitable distance between the blower bar and the respective circumferential surface can be adjusted without impairing the normal operation of the machine.
According to another embodiment of the invention, a positioning device may be provided to positionally adjust the blower bar to a predetermined distance, e.g., between approximately 1 and 20 mm, preferably between approximately 2 and 5 mm, and most preferably approximately 3 mm, from the empty reel or the wound reel. In this connection, the positioning device may preferably include at least one distance sensor. The blower bar can be moved in a suitable fashion via the positioning device.
The positioning device can be activated, e.g., automatically, in the event of a web break, which can be detected, e.g., via a web tension roll. Preferably, the blower bar may be then moved by the positioning device to the predetermined distance from the empty reel or the wound reel, In a likewise manner, the blowing process can be triggered, e.g., in a time-delayed fashion, when the positioning device is activated, e.g., between approximately 5 and 30 s, preferably between approximately 10 and 25 s, and most preferably between approximately 15 and 20 s. This arrangement can simplify the use of the device according to the invention to prevent self-threading, and save blower air.
According to another embodiment of the invention, the blower bar can extend across the entire width of the material web, The advantage of this embodiment is that the entire material web can be acted on with blower air.
By providing at least one separately controllable blowing zone, the blower air can advantageously be applied only in particular regions of the material web. In this manner, the blower air can be applied only in the vicinity of the threading tip of the material web, which can save blower air.
The present invention is directed to a process for threading a material web onto a reel in an apparatus that includes a drum positioned to precede the reel. The process includes guiding a beginning of the material web to be wound around the drum, directing blower air to keep the material web away from the reel, supplying the material web to a preparation station, and threading the reel with the material web.
In accorda
Leitenberger Werner
Maurer Jorg
Moller Roland
Greenblum & Bernstein P.L.C.
Nguyen John Q.
Voith Sulzer Papiertechnik Patent GmbH
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