如何判断分子筛是否需要更换？

  如何判断分子筛是否需要更换？高温除湿机，260度除湿干燥机

# How to Judge Whether Molecular Sieve Needs Replacement 中英双语 ## English ### 1. Dew point keeps high and cannot drop to standard value Under normal working condition, the dew point of PET dryer should stay at -40℃~-50℃. - After cleaning all filters, checking air tightness of pipeline and heating system, dew point still hovers above -30℃ for a long time; - Dew point fluctuates sharply up and down during operation; These are typical signs of molecular sieve failure. ### 2. Visible deterioration after opening adsorption tower Shut down and cool down the machine, open the tower for inspection: 1. Molecular sieve powderizes seriously, a lot of fine powder accumulated at the bottom of tower; 2. Pellets agglomerate into blocks, cannot flow freely; 3. Sieve is contaminated by oil, dust, plastic volatiles, turns yellow, black or grey; 4. Filling volume obviously reduces, lots of sieve leaked out through filter screen. ### 3. Drying effect deteriorates obviously PET materials still have high moisture after standard 4–6h drying, finished products appear continuous bubbles, whitening and haze defects in injection molding. Even prolonging drying time cannot improve quality. ### 4. Short service life reminder Normal 3A molecular sieve service life: 1.5–3 years under clean workshop environment; If the workshop has heavy oil mist, high humidity or long-term operation with dirty compressed air, service life will shorten to 6–12 months, scheduled replacement is required in advance. ### 5. Abnormal noise and frequent filter clogging A large amount of sieve powder circulates with airflow, leading to frequent blockage of post filter; Turbid circulating air causes abnormal friction noise inside the tower during operation. ## 中文对照 如何判断分子筛需要更换 ### 1. 露点居高不下，达不到标准 PET除湿机正常稳定露点应维持在-40℃~-50℃： 清理全部滤芯、检修管路密封性、确认加热系统无故障后，露点长期稳定高于-30℃； 运行时露点大幅上下剧烈波动，无法稳住低露点，说明分子筛吸附能力衰减。 ### 2. 开塔直观检查出现劣化现象 停机降温后拆开吸附塔观察： 1. 分子筛严重粉化，塔底堆积大量细粉末； 2. 颗粒吸水板结结块，无法松散流动； 3. 被油污、粉尘、塑料挥发物污染，发黄、发黑、发灰； 4. 填充量明显变少，大量分子筛从滤网漏出。 ### 3. 物料干燥效果明显变差 原料按标准4–6小时烘干后含水率依然超标，注塑成品持续批量出现气泡、发白、雾斑，延长烘干时长也无法改善不（良）。 ### 4. 使用周期达到更换年限 洁净车间3A分子筛正常使用寿命1.5–3年； 车间油雾大、湿度高、压缩空气含油含水严重时，寿命缩短至6–12个月，需提前计划性更换。 ### 5. 滤芯频繁堵塞、设备异响 大量分子筛粉末随气流循环，后端过滤器极易堵塞； 循环风浑浊，设备运行时塔内出现异常摩擦异响。 ## Supplementary Tip 补充判断小技巧 If only one tower has poor dew point performance, you can swap the two towers for test. After swapping, the high dew point problem follows the original tower, which directly confirms that the molecular sieve of that tower fails and needs replacement. 单塔露点异常可双塔互换测试，互换后高露点故障跟随原塔转移，即可确定该塔分子筛失效，必须更换。