Cleaning of Spinneret

To clean spinneret, you may choose one of the following methods which we recommend:

1.Calcination: In automatic box type furnace, the spinnerets are heated to 450～480℃. When temperature is over 480℃, a superheated steam will pass the calcinator and blow out the     flames to lower the temperature.So that the spinnerets can be prevented from being damaged.

2.Salts Bath: Formed by NaNO₃45%-NaNO₂45%-NaOH10% in mixture, salts bath acts as strong oxidant at its operating temperature, i.e., 450～500℃. The polymer is decomposed to        CO₂ and H₂O very quickly during 60 to 90 minutes. After processed, remaining salts on spinnerets can be washed out by hot water and oxide removed by thin nitric acid.Then it   should be washed sequentially in clean water,ultrasonic tank and dried.

3.Procedyne Fluid Bed: At temperature of 450～500℃,aluminium oxide powder is fluidified by hot air stream and scour the spinnerets. About 70% Polymer is detached and     decomposed. Carbon becomes CO. All these including inorganic substances, such as TiO₂, are discharged in the air.The advantage of this method is that the spinnerets can be   cleaned automatically.

4.TEG: First put spinnerets in boiling solution which contents NaOH(15～20%) for 2 to 3 hours to remove most of the polymer, then in TEG bath at 260～280℃ for about 12 hours.         After cooled,spinnerets should still be washed sequentially in alkaline solution, water and ultrasonic tank before they can be dried and stored up.This process can avoid overheat      and is suitable for any type of stainless steel, but needs rather long time.

5.Vacuum Calciner: Burning in low pressure and vacuum, most of the polymer can be decomposed. Remaining part is washed out by water in the same furnace. The whole
   process can be automatically controlled and easily operated.

喷丝板的清洗:

可用下列各种方法：

1、锻烧法：在自动控温箱式炉中进行。煅烧温度450～480℃，当温度超过480℃时会有过热蒸汽通过炉膛，吹灭火焰，降低温度，以免烧损喷丝板。

2、盐浴法：盐浴大致成分为NaNO₃45%--NaNO₂45%--NaOH10%，盐浴熔点～200℃，使用温度450～500℃。盐浴在该温度时呈强氧化性状态，将聚合物氧化成CO₂和H₂O，作用过程相当快，约60～90分钟即可完成。从盐浴出来后，用热水清洗除盐，再用稀硝酸除去表面氧化膜，然后清水漂洗，超声清洗、干燥。

3、普鲁西丁流化床清洗法：流化床温度450～500℃，以热气流运载氧化铝粉粒，使粘附在喷丝板上的聚合物在气流中受冲刷剥离并分解氧化（约70%的聚合物直接分解，少量的碳粒生成CO），被排出室外。无机物如二氧化钛等留于板面，最终也随气流排出。此法的好处是喷丝板可以自行清洗干净。

4、三甘醇（TEG）清洗法：先将喷丝板置于含15～20%NaOH的沸腾溶液中，时间2～3小时，以清除板上的大部分聚合物。继而将板置于260～280℃的三甘醇溶液中，保持约12小时，然后冷却。冷却后的喷丝板还要通过碱液、清水、超声波清洗以及干燥等处理。本法的优点是操作温度不会过高，能适合各种不锈钢喷丝板的清洗。缺点是清洗时间较长。

5、真空清洗法：在低压真空中灼烧，能使多种化纤聚合物发生分解，残留物在同一炉中被水冲刷干净，能自动控制，操作方便。