Tail threading system for a papermaking machine

A papermaking machine comprising;

• at least one forming fabric on which a paper web is formed;
• a pressing section having at least one press and being without open draws, and in web receiving relationship with the forming fabric so the paper web is transferred between the forming fabric and the pressing section without an open draw;
• a carriage mounted to move in a cross machine direction across the paper web, before the web reaches the at least one press of the pressing section;
• a web cutting means positioned on the carriage and directed towards the web, wherein the web cutting means is mounted for rapid motion in a cross machine direction to cut a paper web tail having a blunt end;
• a dryer section without open draws having a vacuum suction roll positioned to receive the web from the pressing section;
• a means for facilitating the transfer of the tail from the pressing section to the dryer section mounted between the dryer section and the pressing section;
• and
• a means for controlling the vacuum suction roll and the means for facilitating the transfer of the tail, the means for controlling being responsive to the cutting of the paper web tail by the web cutting means to activate the means for facilitating the transfer of the tail when the blunt end of the tail first reaches the means for facilitating the transfer of the tail.

A papermaking machine comprising:

• a forming section with a forming fabric having a paper web disposed thereon;
• a closed draw pressing section engaged with the forming fabric, wherein the pressing section has a pick-up felt extending as an endless loop and receiving the paper web from the forming fabric;
• a closed draw suction pick-up roll disposed within the loop defined by the pick-up felt such that the pick-up felt is guided by and around the suction pick-up roll;
• a first suction press roll disposed within the loop defined by the pick-up felt;
• a first press felt extending as an endless loop having a first backing roll located therein, the first backing roll cooperating with the suction press roll such that the pick-up felt and the press felt extend through a first press nip defined between the first suction press roll and the first backing roll;
• a second backing roll disposed within the loop defined by the pick-up felt, the second backing roll cooperating with a center press roll such that the pick-up felt extends through a second press nip disposed downstream relative to the first press nip, the second press nip defined between the center press roll and the second backing roll;
• a second press felt extending in an endless closed loop, having a third backing roll disposed within the second press felt loop such that the second press felt is guided by and against the third backing roll, the third backing roll cooperating with the center press roll such that the second press felt extends through a third press nip disposed downstream relative to the second press nip, the third press nip defined between the center press roll and the third backing roll;
• a dryer section downstream of the press section, the dryer section having a vacuum suction roll disposed within an endless loop formed by a dryer fabric, the vacuum suction roll located in nipped contact with the center press roll such that a tail with an end on the paper web is guided to the dryer section by the vacuum suction roll;
• a plurality of vacuum rolls disposed within the dryer section downstream relative to the vacuum suction roll;
• a wet end tail cutting means for cutting a tail in the paper web in such a way that the tail reaches full width in a length approximately equal to the tail width;
• a doctor for doctoring the paper web from the center press roll, the doctor located beneath the vacuum suction roll;
• an air jet positioned to direct a flow of air to direct the doctored paper tail against the dryer fabric and vacuum suction roll;
• and
• a controller which synchronizes the traversing of the wet end tail cutter with the activation of the air jet to thread the paper web tail into the dryer section.

A method of threading a paper web through a papermaking machine, which comprises:

• transferring a paper web from a forming fabric onto a press felt without an open draw, passing the web and press felt through at least one nip in a press section, and threading the paper web into a dryer section, the press section having a final press roll defining a roll surface and a final press nip with at least one air jet positioned relative to a doctoring blade for doctoring the paper web off of the final press surface, the dryer section having a vacuum suction roll in contact with the final press roll surface for guiding the doctored paper web against a dryer fabric for threading into the dryer section;
• traversing a wet end tail cutter, positioned before the final press nip, across the moving web in the cross-machine direction at a rate of speed approximately equal to or greater than the rate of speed of the moving web to form a blunt tail end;
• and
• energizing the vacuum suction roll and plurality at least one air jet positioned at the doctoring means in synchronization with the cutting of the blunt tail end, such that the air jets and vacuum suction rolls are engaged approximately simultaneous with passage of the blunt tail end over the doctor blade, to thread the tail into the dryer section without a streamer.