From the experience of the development of foreign papermaking industry and the current level of domestic papermaking technology and equipment, the potential of using blankets (high-line presses, nets, acupunctures and blankets) to replace the full-fiber needled blankets (abbreviated as BOB blankets) commonly used by domestic papermaking companies is very high. Big and imperative. At present, some domestic blanket manufacturers not only have produced papermaking blankets suitable for medium and high-speed paper machines, but they have also developed chemically processed blankets that can replace imported products within a certain range.
1 Structure of BOM Papermaking BOM Papermaking blankets can be divided into three series according to the structure: single-layer bottom net blankets, double bottom net blankets, and multi-layer bottom net blankets; depending on the application, they can be divided into: BOM forming blankets, BOM Press carpet, BOM upper blanket, BOM dry blanket, BOM pulp blanket and so on. The BOM carpet is generally composed of a bottom mesh layer and a fiber layer, wherein the bottom mesh layer is divided into three types: single layer, double layer, and multi-layer, wherein the double bottom mesh is further divided into a double structure and a "1 10 1" composite structure. The multi-layer bottom network is divided into "l+2" and "2+2" composite structures. All the nets consist of warp and weft yarns made of nylon monofilament or monofilament plaiting and weaving with different weaving methods. The fiber layer is composed of polyamide fiber staples of different thicknesses. The combination of the fibrous layer and the bottom layer is accomplished by a needling process.
2 The performance of BOM papermaking carpet 2.1 Excellent drainage and permeability, high porosity, easy to clean the blanket, not easy to be blocked by foreign matter, ideal for large-scale vertical dewatering such as vacuum and blind holes.
2.2 The felt has good elasticity and the internal network has incompressibility. It can withstand extremely high line pressure and can be used up to a line pressure of 300kN/m, which can effectively reduce the moisture of the wet paper sheet in the area of ​​service, reduce the breakage of the paper sheet, and facilitate the increase of the vehicle speed.
2.3 With high tensile strength, it is not easily broken or torn under high pressure and high load conditions. The structure is stable, the stiffness is good, it is not easy to be discounted, and the elongation and shrinkage rate are extremely small, generally not more than 1%.
2.4 The blanket is flat and thick, which is beneficial to improve the appearance quality of the paper, and can effectively reduce and eliminate impressions such as carpet marks, groove marks, blind hole marks, true scratch marks, and the like.
2.5 Long service life, wear resistance. Wear-resisting, chemically treated blankets have the characteristics of anti-pollution, anti-fluffing, etc. Its comprehensive performance is equivalent to that of imported blankets and is 30%-50% longer than that of ordinary blankets.
3 Requirements of the papermaking Machine for the BOM of papermaking machines 3.1 Requirements The paper machine has a high degree of vacuum in the entire negative air system, and the configuration of the vacuum pump and the setting of the vacuum box are reasonable. According to the structure of the paper machine and the different types of paper produced, one system requires a vacuum of 0.049 MPa or more. The washing vacuum box should be separated from the dehydration vacuum energy vacuum system. The vacuum pressure roller low pressure zone is really above O.030MPa, and the high pressure zone vacuum should be above 0.049MPa.
3.2 BOM papermaking blankets are more suitable for large presses such as grooves, blind holes, vacuum, and large roller diameters. This type of tree press facilitates the vertical dewatering of the felt itself.
3.3 BOM Papermaking Blanket requirements The papermaking machine has good washing conditions, especially BOM forming blankets, BOM pre-press felting blankets, BOM press blankets.
3.4 dedicated blanket. Different types of blankets should be used for paper machines that produce different paper products.
BOM papermaking blanket maintenance 4.1 BOM papermaking blankets are designed for specific press sites, different press parts of the blanket should not be used for each other, some paper mills have not yet received enough attention, often there will be papermaking blankets and pressing a fit phenomenon, it is difficult Play blankets should have performance.
4.2 The BOM papermaking felt has a very strong positive and negative performance difference. Before being put on the machine, it must be seen clearly and positively. It must not be installed in reverse. It should be run in the direction specified by the arrow.
4.3 Be sure to flatten before applying pressure. Before the normal production of paper, the tension of the felt should be tightened at one time without prior relaxation. During the middle and later stages of tensioning, the general tension requirement is 2.45-4.41 kN/m.
4.4 The BOM forming blanket is used on the rotary screen machine. If the load is too heavy, the tension of the blanket is too large. It is better to transfer the first tray roller to the blanket roller after the main pressure is pressed out, and ensure that there is enough between the roller and the front roller. Distance to prevent blankets from breaking.
4.5 The non-pressurized setting and chemical treatment of the BOM blanket air running time requirements are relatively long. When the air is running, the alkali water softens the surface fibers to improve the adaptability of the initial paper production of the blanket.
4.6 BOM blankets should be used in combination with high-pressure moving water pins, fan-shaped water sprays, and vacuum suction boxes. High pressure moving water needle pressure should be different according to the speed of the vehicle, using different water pressure, generally required in the 0.6-2.5MPa, fan-shaped water spray pressure requirements in the O.2-0.4MPa, vacuum box suction vacuum requirements in the O. 030MPa or less.
4.7 BOM blanket washing requires continuous washing and regular washing. Regularly wash some laundry detergents such as paper-making blankets and non-ionic surfactants. The key dirty department uses high-pressure water guns and detergents to focus on washing. If you need to use pickling, you should control the washing time and concentration, a requirement of not more than 5% of dilute acid washing 15min, and timely rinse with water.
The above is a summary of the structure, performance, use and maintenance of BOM papermaking blankets. Compared with BOB blankets, BOMt blankets have a layer of incompressible underlay, which makes BOM blankets have a larger water capacity. During the dewatering process, a portion of the water passes through the felt and flows away. A portion of the water is carried away in the bottom web of the BOM, and is sucked away by the vacuum box on the return journey. This is the fundamental difference between BOM blankets and BOB blankets. In actual production, proper blanket washing conditions, reasonable pulp washing degree, and full understanding of the performance of the felt are the key to using a good papermaking felt to prolong its life.
1 Structure of BOM Papermaking BOM Papermaking blankets can be divided into three series according to the structure: single-layer bottom net blankets, double bottom net blankets, and multi-layer bottom net blankets; depending on the application, they can be divided into: BOM forming blankets, BOM Press carpet, BOM upper blanket, BOM dry blanket, BOM pulp blanket and so on. The BOM carpet is generally composed of a bottom mesh layer and a fiber layer, wherein the bottom mesh layer is divided into three types: single layer, double layer, and multi-layer, wherein the double bottom mesh is further divided into a double structure and a "1 10 1" composite structure. The multi-layer bottom network is divided into "l+2" and "2+2" composite structures. All the nets consist of warp and weft yarns made of nylon monofilament or monofilament plaiting and weaving with different weaving methods. The fiber layer is composed of polyamide fiber staples of different thicknesses. The combination of the fibrous layer and the bottom layer is accomplished by a needling process.
2 The performance of BOM papermaking carpet 2.1 Excellent drainage and permeability, high porosity, easy to clean the blanket, not easy to be blocked by foreign matter, ideal for large-scale vertical dewatering such as vacuum and blind holes.
2.2 The felt has good elasticity and the internal network has incompressibility. It can withstand extremely high line pressure and can be used up to a line pressure of 300kN/m, which can effectively reduce the moisture of the wet paper sheet in the area of ​​service, reduce the breakage of the paper sheet, and facilitate the increase of the vehicle speed.
2.3 With high tensile strength, it is not easily broken or torn under high pressure and high load conditions. The structure is stable, the stiffness is good, it is not easy to be discounted, and the elongation and shrinkage rate are extremely small, generally not more than 1%.
2.4 The blanket is flat and thick, which is beneficial to improve the appearance quality of the paper, and can effectively reduce and eliminate impressions such as carpet marks, groove marks, blind hole marks, true scratch marks, and the like.
2.5 Long service life, wear resistance. Wear-resisting, chemically treated blankets have the characteristics of anti-pollution, anti-fluffing, etc. Its comprehensive performance is equivalent to that of imported blankets and is 30%-50% longer than that of ordinary blankets.
3 Requirements of the papermaking Machine for the BOM of papermaking machines 3.1 Requirements The paper machine has a high degree of vacuum in the entire negative air system, and the configuration of the vacuum pump and the setting of the vacuum box are reasonable. According to the structure of the paper machine and the different types of paper produced, one system requires a vacuum of 0.049 MPa or more. The washing vacuum box should be separated from the dehydration vacuum energy vacuum system. The vacuum pressure roller low pressure zone is really above O.030MPa, and the high pressure zone vacuum should be above 0.049MPa.
3.2 BOM papermaking blankets are more suitable for large presses such as grooves, blind holes, vacuum, and large roller diameters. This type of tree press facilitates the vertical dewatering of the felt itself.
3.3 BOM Papermaking Blanket requirements The papermaking machine has good washing conditions, especially BOM forming blankets, BOM pre-press felting blankets, BOM press blankets.
3.4 dedicated blanket. Different types of blankets should be used for paper machines that produce different paper products.
BOM papermaking blanket maintenance 4.1 BOM papermaking blankets are designed for specific press sites, different press parts of the blanket should not be used for each other, some paper mills have not yet received enough attention, often there will be papermaking blankets and pressing a fit phenomenon, it is difficult Play blankets should have performance.
4.2 The BOM papermaking felt has a very strong positive and negative performance difference. Before being put on the machine, it must be seen clearly and positively. It must not be installed in reverse. It should be run in the direction specified by the arrow.
4.3 Be sure to flatten before applying pressure. Before the normal production of paper, the tension of the felt should be tightened at one time without prior relaxation. During the middle and later stages of tensioning, the general tension requirement is 2.45-4.41 kN/m.
4.4 The BOM forming blanket is used on the rotary screen machine. If the load is too heavy, the tension of the blanket is too large. It is better to transfer the first tray roller to the blanket roller after the main pressure is pressed out, and ensure that there is enough between the roller and the front roller. Distance to prevent blankets from breaking.
4.5 The non-pressurized setting and chemical treatment of the BOM blanket air running time requirements are relatively long. When the air is running, the alkali water softens the surface fibers to improve the adaptability of the initial paper production of the blanket.
4.6 BOM blankets should be used in combination with high-pressure moving water pins, fan-shaped water sprays, and vacuum suction boxes. High pressure moving water needle pressure should be different according to the speed of the vehicle, using different water pressure, generally required in the 0.6-2.5MPa, fan-shaped water spray pressure requirements in the O.2-0.4MPa, vacuum box suction vacuum requirements in the O. 030MPa or less.
4.7 BOM blanket washing requires continuous washing and regular washing. Regularly wash some laundry detergents such as paper-making blankets and non-ionic surfactants. The key dirty department uses high-pressure water guns and detergents to focus on washing. If you need to use pickling, you should control the washing time and concentration, a requirement of not more than 5% of dilute acid washing 15min, and timely rinse with water.
The above is a summary of the structure, performance, use and maintenance of BOM papermaking blankets. Compared with BOB blankets, BOMt blankets have a layer of incompressible underlay, which makes BOM blankets have a larger water capacity. During the dewatering process, a portion of the water passes through the felt and flows away. A portion of the water is carried away in the bottom web of the BOM, and is sucked away by the vacuum box on the return journey. This is the fundamental difference between BOM blankets and BOB blankets. In actual production, proper blanket washing conditions, reasonable pulp washing degree, and full understanding of the performance of the felt are the key to using a good papermaking felt to prolong its life.
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