How To Pick Up The Paper Sheet From Forming Fabric To Press Felt?

How to Transfer The Paper Sheet from Forming Fabric to Press Felt?

Paper Machine Pick-up Method

There are generally three ways to transfer wet paper sheets from the couch roll to the press section, namely: open type pick up , stick paper type pick up, and vacuum type pick up. Choose which method of pick up paper, depend on machine speed and paper weight.

Open Type Pick-up

Open type pick-up is commonly used in medium and low-speed foudrinier paper machines to transfer paper from the forming section to the press section.

Open type pick-up use needle nozzle to cut the wet paper sheet to 50-100mm narrow strip after transferred to couch roll.

For low-speed paper machines with normal couch roll, generally use manual pick-up machine, which sticking a narrow strip of paper that has passed through the couch roll with a semi dry pulp and guiding it onto the press felt;

For paper machines that use suction couch roll, a compressed air nozzle installed inside the suction couch can be used to blow up wet paper sheets at a pressure of 4-6 atmospheres and send them onto the press felt.

Stick Paper Type Pick-up

This method is suitable for middle speed and low paper weight paper machine.

The stick paper pick-up is the process of applying wet paper from couch roll onto pick up felt, relying on the adhesion of a thin layer of water film on the felt surface and the weak suction effect of rotation.

This method require the felt have sturdy structure, tightly woven, flat surface, and needs to be brushed. And the felts (especially the two edges) must be cleaned during operation.

Vacuum Type Pick up

For high speed paper machine, due to the machine speed is too high so it’s difficult to use open type pick up paper, so that the majority of paper pick up from the forming section to the press section is done in a closed manner, using a vacuum pick up paper device.

In order to facilitate pick up paper, the forming fabric has a straight section with an inclination angle of about 45 ° after passing through the suction press roll. The wet paper sheet is here, and is sucked away from the forming fabric by the suction press roll through the combined action of vacuum and tube, and attached to the line felt. Then, through the paper pick up press, the wet paper sheet is transferred to the first press felt, and then enters the second press (the paper pick up press and the first press share the same felt).

The position of the suction pick up roll can be located between the suction couch roll  and the driving roll, or near the driving roll.

The structure of the suction pick up roll is similar to that of the suction press roll. When starting the paper pick up process, gradually lower the suction pick up roll to make contact with the forming fabric, and the vacuum degree of the paper pick up is generally 300-400mmHg.