1.Overview

The refining process is a major consumer of electricity in the entire tire production, and improving refining efficiency and reducing refining energy consumption has been an important topic of research in the industry. The low temperature primary refining technology changes the traditional multi-stage mixing technology into a one-stage mixing technology. This technology achieves continuous production of mixing, one-time final rubber, high automation and high production efficiency; reduces the number of operators and ensures stable rubber quality, so the low-temperature primary rubber refining system also has very high requirements for automation control and drive.

A large tire factory in Guangdong has launched two sets of low-temperature primary rubber mixing systems, and NewSky ME series special inverter has become the drive inverter for these two systems with its specialization, stability and convenient communication function.

2. Process introduction

The low temperature primary refining method is to put the rubber discharged from the compacting machine into 0# refining unit first, after a short time of mixing, so that the rubber can be cooled down and formed into sheets, which is easy to convey; through the automatic queuing of the program, it is conveyed to one of the 1-6# units, on which the rubber cooling, mixing, sulphur addition, refining, discharging to the pressing and opening machine to discharge the sheets, and finally cooling and stacking on the film cooling line to complete a truckload of rubber. The mixing of the film is completed. In this process, after the rubber is discharged from the compactor, it does not need to go through the process of parking and so on, but only needs to go through the knapper to complete the final refining. The system employs six sulfur-added refining units, which work in tandem with the refiner to maximize capacity.

3.System Configuration

3.1 System drive diagram

Figure 1 Drive diagram of the low temperature primary refining system

The project uses 11 ME series frequency converters for the low-temperature primary refining system: 2 for the compacting machine and 9 for the knapping machine. The system control bus uses the Profinet communication bus method, which is more implementable, and Profinet, as an Ethernet bus method, can transmit TCP or IT data at the same time, making factory automation easier to realize.

Table 1 Single primary refining drive configuration

3.2 Features of the ME500 low voltage inverter drive for the knapper

1）ME500 low-voltage inverter adopts advanced motor model control and open-loop vector control in the field, which can quickly respond to load abrupt changes and meet the requirements of open refiner load drive.

2）Accurate rotor magnetic chain orientation control capability, fast response and stable operation even at 0Hz load torque abrupt change.

3）0.1s full load acceleration, fast torque response, small speed overshoot, improve production efficiency.

4）Communication bus control, more convenient control and stronger anti-interference ability.

Figure 3-4 Inverter cabinet in field commissioning

Figure 5-6 Process system diagram of tandem compacting machine and primary refiner (0#, 7#)

4 Summary

ME series special inverter is successfully used in the low temperature primary refining system. The whole refining system saves about 10%-15% energy than the traditional DC speed control system, which provides a new direction for the energy saving and emission reduction of the factory.