MAKE/MODEL: Progressive 2000 System 2000
DESCRIPTION: Tail threader for Size press (New) This apparatus and method for threading a tail (sheet) through a dryer section of a papermaking machine in particular at the size press station.
BACKGROUND OF THE APPLICATION: The Tail Threding System employs a low pressure water jet which is mounted on a pneumatic actuator with a piston which can move ideally at least as fast in the cross machine direction as the paper web moves in the machine direction for a distance of 2 to 12 inches. Thus the low pressure water jet cuts a tail of 2 to 12 inches wide from the paper web.
The pneumatic actuator is mounted on a conventional screw or belt driven mechanism which traverses the width of the web. The pneumatic actuator allows a tail to be formed in the web with an identifiable beginning by
rapidly moving the water jet from the edge of the web towards the center of the web to form the tail.
The tail thus formed has a distinct beginning point defined by an edge which is ideally at most inclined forty-five degrees from a cross machine direction line.
The screw mechanism is used to continue the traverse of the low pressure water jet across the web, after
the tail has been threaded through the dryer section. Thus the screw mechanism widens the tail until it is as wide as the entire web and thus completes the threading process.
A controller coordinates an air jet positioned beneath a doctor blade on the last press roll. The air jet is actuated just before the beginning of the tail engages the doctor blade. In this way a tail with little or no streamer is formed and blown onto a dryer fabric supported on a vacuum roll which leads the tail into a single tier dryer section.
It is a feature of the present invention to provide a threading apparatus that both safely and efficiently threads a paper web through a papermaking machine. It is another feature of the present invention to provide a method of cutting a tail in a paper machine that eliminates long streamers of spent tail.
It is a further feature of the present invention to provide a paper machine threading apparatus that eliminates the need for the use of threading ropes. It is also a feature of the present invention to provide a dryer vacuum roll which engages the last press roll. Further objects, features and advantages of the invention will be apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 Tail Threading System
FIG. 1 is an isometric view of a prior art papermaking machine
llustrating how a streamer attached
a threading tail can be pulled out of
a broke pit when the tail is threaded into a dryer section.
FIG. 2 is a schematic view of a paper web moving through a
the threading apparatus of the present
FIG. 3 is an isometric view of a paper web tail being cut using the
method and apparatus of the present invention.