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How can the service life of the flights in a triple-pass dryer be extended?
release time:
2026-10-17
After a triple-pass rotary dryer has been running for one or two years, many customers find that the drying performance has noticeably declined—at the same hot air temperature, the moisture content of the discharged mate
After a three-pass rotary dryer has been running for one or two years, many customers find that drying performance has noticeably declined—at the same hot air temperature, the moisture content of the discharged material is higher than before, and undried "wet clumps" often appear at the rear of the drum. When the heat source and rotation speed are checked and found normal, the problem usually lies with the lifting flights.
Once flight wear exceeds one-third of the original height, the material can no longer be lifted. The function of the lifting flights is to carry the quartz sand up to a certain height and then drop it, forming a material curtain that fully contacts the hot air. As the flights wear thinner and shorter, their material-lifting capacity decreases, and a large amount of wet sand accumulates at the bottom of the drum, forming a "dead material zone" that greatly reduces the heating surface area. The diagnosis is simple: after shutting down, enter through the manhole, measure the flight height with a tape measure, and replace them once wear exceeds one-third.
If the spacing between lifting flights is too large, the material curtain will not be fully covered. Normal spacing should be kept between 150-200 mm. When spacing is too large, no material is lifted in the areas between flights, and the hot air passes straight through the gaps, significantly reducing thermal efficiency. During inspection, measure section by section along the drum axis; where spacing is uneven or exceeds 200 mm, weld on additional flights or adjust the position of the existing ones.
Choosing the wrong flight material can multiply the wear rate. Ordinary carbon steel flights are worn down substantially within three to five months under the scouring action of quartz sand. It is recommended to use flights made of wear-resistant steel (such as NM400), whose wear resistance is more than three times that of ordinary carbon steel. Be sure to tighten the bolts during installation to prevent loosening and falling off due to operating vibration. After replacing the flights, run the dryer without load for half an hour and confirm there is no loosening before feeding material.
During routine inspections, watch for "wet clumps" or unevenly dried material at the discharge end. If the heat source temperature is normal but drying performance continues to decline, check the flight wear first. Shanlu Heavy Industry has accumulated years of experience in the field of quartz sand drying equipment and can provide customized flight solutions and replacement recommendations based on drum specifications. If you encounter problems during equipment operation, you are welcome to contact the Shanlu Heavy Industry technical team: Manager Zhang 13583776655 (same on WeChat).
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