The Development Of Producing System For Irradiation Cross-linked Heat Shrinkable Materials Of Engineering Piping Amendment And Protection

Some polymer materials can be cross-linked by high energy rays irradiation, thus get the function of shape memory, and their mechanical properties, resistance to environment and heat have also been enhanced greatly. Heat-shrinkable materials made from cross-linked polymer have been universal applied in many industry fields.Up to now, among the several technologies of mending and protecting of engineering pipes welds, such as coating by pitch, coal tar, epoxy resins and coal tar mixture, and wrapping with plastic adhesive taps and so on, the application of irradiation cross-linked heat-shrinkable materials in mending and protecting of engineering piping is the most advanced technique, it takes more than 80% of the whole market.There are observable gaps existed between the domestic irradiation cross-linked heat-shrinkable materials and the foreign ones both in the quality and the output. The production of the unexpanded tape takes the most critical role in the whole producing process. In order to reduce the gaps to the foreign product, and expand the international market, Sichuan Jiu Yuan pays great effort on the development of new techniques and crucial production devices for irradiation cross-linked heat-shrinkable materials. As one component part of the whole project, our works are focused on the developing of the unexpanded tape producing techniques and the corresponding producing equipments.Under the requirements of the irradiation cross-linked heat-shrinkable materials for mending and protecting of engineering piping, the following works on the developing of the production devices for unexpanded tapes have been completed:1.The producing routine and the collective scheme of the system have been determined. The functionalities of the producing system are extending, elongating, and combining. And the system are made of six subsystem, they are extruding, extending & elongating and combining, pulling, cooling, picking up, and controlling subsystem, respectively.2.Studies on the design of extruding subsystem. The materials and structure of the crucial part, such as, screw, barrel, and die have been selected. And the mechanical strength of screw and barrel have been calibrated.3.Studies on the design of extending & elongating and combining subsystem. The arrangement style, inner structures and the driving method of the rolls have been determined. The rigidity of the rolls has also been taken into consideration.4. Design of the pulling, cooling, and picking up subsystems. 5.Studies on the controlling subsystem. It includes speed and temperature controlling. The temperatures are controlled with a PID. the speeds of the extruder, extending, elongating, combining, pulling and picking up are adjusted collectively or individual with a PLC controller.