Drying five of the hottest future paper machine at

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Future paper machine: drying at high speed (V)

low pressure differential has the advantages of low steam flow and less corrosion to steam equipment. A key reason is that the mechanical rigidity of the siphon can not only prevent failures, but also maintain a stable and suitable spacing between the water diversion bracket and the shell

Johnson answer: on the modified paper machine, changing from rotating siphon to fixed siphon reduces the overflow problem of drying cylinder, and can provide more stable and reliable drying cylinder operation. For the new paper machine with blanket drive dryer, it is particularly important to fix the siphon. Because it can prevent overflow of the drying cylinder, fixing the siphon can minimize the change of drying speed and reduce broken ends. The zero differential pressure siphon will enable the paper workers to continuously empty the dryer and avoid all kinds of potential overflows, which will maximize the heat transfer to the paper web. Because the pressure difference is zero, these siphons can be designed and operated flexibly

there is no need to change the operating performance of the siphon when the paper type, vehicle speed or other operating parameters change. The energy loss of the condenser caused by the differential pressure of the siphon is eliminated, and the total efficiency of the machine is improved

the new adapter will generate information such as pressure measurement, flow rate, differential pressure, etc. the measurement of steam flow at each joint to speed up the upgrading of products can enable the staff to check the drying cylinder with poor performance and take action to solve the problem. Because the sensitive connector can display the service life of the internal components and send the information that the equipment needs to be repaired to the operator, this reduces the downtime and improves the efficiency

in addition, the full width turbulence device will provide uniform banner drying and improve the drying capacity. This is very important in the transformation of the paper machine, because it allows the single-layer drying part to be longer. In the long run, the overall efficiency of siphons and spoiler rods, even steam and condensation systems, is also important

using the correct monitoring system can significantly improve the siphon technology, which depends on the operator's ability to quickly respond to the fault location or adapt to high-efficiency drying operation. Even fuzzy logic collected by software according to the intelligence of the operator can be used

TAPPI magazine asked: is the synthesis of the drying section useful for 3000 ~ 3600m/min paper machines? What improvements need to be made

Beloit A: for high-speed operation, the cadre synthesis technology needs to be improved. At such a high speed, in order to maintain good thermal contact between the wet paper web and the surface of the dryer, the tension of the cadres must be increased. The cadre must be designed to carry the load and transmit higher transmission power to the dryer through surface contact

in order to cope with the increased drying rate in high-speed production, cadres must have high temperature resistance. The large diameter blanket roll that can withstand this high tension must be able to support the cadres. The blanket roll is too large to be installed in the pocket of most traditional dryers. This requires other dryer structures. The surface structure of the cadres must be improved to reduce the amount of air entering and the damage of the paper. The reaction time of the guiding system must be improved to avoid wearing edges

Gardner answer: when the drying cylinder operates at 3000 ~ 3600m/min, the stress and strain on the radial line are very large. There is no problem with the paper guide, but there is a great practical danger. Although it is not obvious now, there will be a problem in case of component failure. It is conceivable that due to tension failure, the drying cylinder will be stacked after breaking, and its height will exceed 100M/h

jhk answer: in recent years, the dryer blanket has been improved and designed to be breathable and meet the needs of high speed and high tension. The main problems of drying cylinder blanket at high speed are paper guiding and preventing sudden accidents of paper winding

Johnson answer: the speed difference caused by different drying cylinder diameters can be adjusted for the blanket transmission cadres of the new paper machine. This greatly affects the requirements for drying cylinders. The dryer must be designed to be flat and thin. In this way, when the paper runs around the vacuum steering roller, its elongation can be reduced and the running performance can be improved. Another factor affecting the blanket is the high characteristic chemistry of the wet end, which significantly improves the drying efficiency through rapid dehydration, because the cadres need less evaporation, which will significantly affect the design of the dryer

thermowisconsin A: Yes, the current blanket can work. Using computer PLC technology will improve the rapid response of the calibration system, which can provide the required accuracy tolerance

TAPPI magazine asked: what is the problem of guiding paper pages and papermaking fabrics on a fast paper machine

beloit answer: the guidance of the paper web is a problem of operation performance, and the necessary requirement for the high-speed operation of the paper web is that the whole process should be fully loaded. Now, this bearing is provided through the top blanket and other single-layer cadres (such as beloitbelruntm and Bel champtm cadre structures). In the future, this bearing system will be further improved to provide safe, reliable and controllable bearing for the paper web in all links. Now, several structures that can meet these requirements have been introduced

GL V answer: with the increase of the speed of the paper machine, paper control becomes increasingly important. Due to the increase of vehicle speed, the transmission pressure, rolling and dryer structure of the dryer must be considered, including the air control device. The key to high-speed operation performance is to control the paper jitter and the air volume in the dryer bag area

within this speed range, the current guiding device can be mechanically operated. Direction finding of blanket position may require non-contact sensors to eliminate excessive wear. In addition, the discretionary use system will need a faster response time

jhk answer: high speed shortens the reaction time to prevent machine damage. As the constraint time becomes shorter, the ability to prevent the deterioration of paper test performance will become worse. (end)

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