The ball type paraffin removal unit has low reliability in moving; while the tooth type unit has the disadvantages of teeth being apt to break and causing damage of tubing inwall.

• 球型清蜡器的主要缺点是运动的可靠性差，一旦钢球丧失锁紧功能，将失去“步进足”的作用；而齿型清蜡器的步进齿易破损及齿尖易刺伤油管内壁。