Stretchers are developed to automatically control the felt and wire tension in the press and dryer section of the paper machines. It includes a lever arm and a mass cooperating to exert a rotational force on a roll carrying the felt, whose rotation is converted to a lateral movement of the roll into the felt, thereby stretching the felt.
Operation :
The tension of the felt or wire is sensed by the sensor linked directly to the tensioning device. If the tension deviates from the set value, the tension roller is adjusted accordingly by means of chain or rack and pinion driven by motors in relation to signals sent from the control unit. In case of emergency it can be adjusted manually with the help of a hand wheel.
System Advantages :
1.
Precise tension control
2.
Increase in drying efficiency thereby improving the quality of paper
3.
Reduces the consumption of steam
4.
Reduces sheet breaks
5.
Avoids slippage of drive rolls
6.
Less expensive than the gear boxes and cross shaft system which have been used previously.
System features :
1.
Tension device driven by gear motor drive
2.
Backlash and friction free power transmission by chains/ Rack and Pinion
3.
Refined lateral movement by the air bellows
4.
Sensing device on one side which measures the tension in the roll.
