Paper-forming Nets Are Prone To Problems And Causes

Molding net is an important equipment on paper machine. It is a device for forming and dewatering paper on paper machine. It dehydrates the pulp suspension from the headbox and runs the paper web to the subsequent section. The polyester forming net is a general water filter net for the forming part of the paper machine. It used to use copper mesh and polyester mesh. The forming mesh was mainly made of polyester monofilament. In order to increase the service life of the forming wire, some manufacturers added nylon monofilament weaving with better wear resistance in the weft.

Paper-making nets are prone to problems and causes

First, the mesh edge wears too fast: the most serious wear of most paper machines is in the joint with vacuum and no vacuum (10-375px position of the mesh);

Solution: 1. Try to increase the width of the vacuum box opening in sequence. 2. Apply atmospheric pressure lubricating water to the edge of the vacuum box. 3. Apply reinforcing ribs at appropriate locations. 4. Check if the edge wiper and vacuum box have corners or gaps. In particular, the seam of the ceramic panel is a weak link. 5. Check whether the edge of each roller is seriously worn (the diameter becomes thinner after the wear, so that the tension of the mesh is smaller than the normal mesh surface to further accelerate the wear)

Second, the overall wear is too fast:
1, panel quality but off
2. The mesh tension is too small, the single-layer net return tension is 3-4kg/cm, and the return tension of the two-layer forming net is 5-6kg/cm.
3. The quality of the filler is poor.
4, the mesh breathable large filler loss, too much filler particles between the net and the vacuum box panel will also be faster than the overall wear of the fast mesh.
5, the net ventilation small filter water is slow, only the increase in vacuum speeds up wear.
6, the guide roller speed and network speed are not synchronized.
7, the network speed of the upper and lower network is not synchronized.

Third, the local longitudinal length is too fast wear: whether the forming plate, the wiper plate, the vacuum box panel are wrong, uneven and notched; whether the rollers have local wear and rust.

Fourth, the partial longitudinal length of the drum: whether the molding plate, the wiper plate, the vacuum box panel is wrong, uneven, whether the chest roller vacuum roller has protrusions such as solder joints, whether the rubber roller has impurities.

5. Guide roller sizing: cleaning water pressure low mesh internal fiber; low mesh ventilation; cleaning method has two layers of half mesh should clean the paper exit surface, nozzle is blocked, the optimal distance between nozzle and mesh is 15 -500px.

Sixth, the vacuum box topping: the mesh permeability is not suitable, the pulp fiber is shortly lost, the retention agent quality is not good or the addition amount is small.

Seventh, when the network is running, the amplitude of the movement is large: the corrector works abnormally, and the network edge is not straight.

8. The net is narrowed after a period of use: the partial wear of the forming plate, the wiper plate, the vacuum box panel or the guide roller causes the mesh to run for a period of time, and the marking line becomes inclined (the local mesh is not working properly).

Nine, plus D-type device and the previous network life comparison: Add D-type device can effectively solve the two sides of the paper, speed up the dehydration and increase the speed, but the life of the forming net will decline, mainly because the water line becomes shorter and the wear is accelerated. Usually life expectancy drops by 1/3 or even 1/2.