This paper introduces the status of cleaning techniques for condenser at present,expands the advantage of auto cleaning techniques for plastic twister.

0 m/s,and it is difficult to have self-clean by using plastic twisted tape.

The technique of plastic twisted tape c an not only self-clean away the fouling but also enhance heat transfer.

The analysis of some problems in the design of plastic belt;

To study the relations between main structure parameters of sliding plastic belt and intensity of belt by experimented and analyzed on simulative projectile.

The mechanisms of decreasing initial disturbance and increacing firing dispresion by the action of sliding plastic belt of fin-stabilized projectiles in a rifled gun and gas-tightening plastic belt of spin-stabilized projectile are experimentally studied.

The plastic strip-insert with oblique teeth has the greater heat transfer invigoration effect compared to twisted-insert smoothly,the heat transfer strength scope is 5 times than the traditional plastic belt,it is suitable to the numerous quantity low speed flow heat-changer with speeds of 1.