Excessive hydraulic pressure within the press nip damages the web structure by over-draining water, resulting in sheet crushing. Inspect the felt tensioning and felt guiding devices. Wash or replace dirty, clogged press felts; check felt design and wear conditions. Check for blockages in felt Uhle boxes and/or raise vacuum level. Test pulp freeness; lower beating degree or adjust fiber furnish to improve freeness. Reduce press nip load to prevent rewetting between nips; inspect shower water and clean clogged spray nozzles. Consider revising the felt design or lowering machine speed to extend dwell time in the press section. Clean or replace suction press rolls; inspect Uhle box seals for air leakage; check pulp buildup on press roll surfaces, which may trigger crushing. Verify camber and crown curvature of press rolls; replace rolls if necessary. Excessively hard roll covers can cause sheet crushing. Likewise, check vacuum level of suction press rolls. Check and adjust load distribution evenly across the pres

How to Fix Wire Marks on Paper Adjust the slice lip toward the apron to reduce dewatering on the breast roll. If feasible, adjust the curvature of the apron slice lip so that the ejected pulp travels further forward along the forming wire. Reduce refining for pulp with slow dewatering performance. Gradually increase the vacuum level of vacuum boxes and put all vacuum boxes into service. Tighten the forming wire if it is too loose. Raise the headbox consistency to lower the moisture content of the paper web. Inspect the position and alignment of forming boards, dewatering elements and vacuum boxes. Raise the position of the dandy roll. Reduce the load of press rolls. Evaluate the feasibility of adopting a higher-mesh forming wire. Wire marks are sometimes related to the degree of fiber penetration through the forming wire. Excessive dewatering during initial forming will cause fiber ends to stand upright and embed into the forming wire. Excessive dewatering without turbulence may seal the paper web. This resul

Excessive dilution water is added to the vacuum broke chest. Especially when the chest only processes paper trims, check the spray water control and water pressure. Overflow from the wire pit flows into the vacuum broke chest. Adjust the overflow of the wire pit to prevent excessive dilution water from entering the broke handling system. The vacuum broke chest has insufficient capacity to process wet broke. Modify the dispersing equipment to meet the dispersion requirements for full-width broke. Inspect all pumps and control systems equipped for the broke handling system. Verify whether the pump capacity can meet high flow demands, and check the length of the pump suction line. Check the control configuration of the vacuum broke chest. Broke floats in the pulper. The pulper shall submerge the broke and defiber it promptly. Adjust the position of the spray pipe. Check the circulation system. Ensure sufficient agitation to draw the broke into the rotor area. Liquid level fluctuation occurs in the broke pulper.

Causes of forming fabric arching White water continuously flows to a single point on the inner side of the forming fabric. Remove accumulated fibers and take proper measures to eliminate factors causing white water tray overflow. Pulp deposits on breast roll, press roll and turn roll, which are formed as water flows around the rolls. Check the alignment of breast roll, couch roll and turn roll through the seam line and running track of the forming fabric. Remove burrs on all rolls including table rolls. Clean the holes of the couch roll before installing the forming fabric. Replace worn dewatering elements and turn rolls. Adjust the tension of the forming fabric with tension rolls and stabilize tension fluctuation. Consider installing spreader rolls on the fabric return path. Repair or replace worn and deformed vacuum boxes. Reduce vacuum degree to avoid suction and dragging of the forming fabric. Internal arching is mainly caused by pulp deposits on internal breast rolls, turn rolls, couch rolls an

The main spare parts of the dryer section are dry fabrics and felt ropes. Damage and premature removal of dry fabrics are mostly caused by external and operational factors. Common faults include holes, edge cracking, local creasing, fabric wandering, and squeeze breakage. Except for unexpected and unavoidable failures, most of these problems can be prevented by careful and standardized operation.