Aiming at some problems existing in the roll-bag workshop, this paper upgrades the main control, programming, HMI and communication of the injection controller, and adds new and effective functions, so as to achieve the best dust removal effect, visual monitoring and operation pictures, and effectively guarantee the normal production of the workshop. Dust-laden air enters the intake box from the intake port. Coarser particles of dust settle down by their weight and fall into the ash hopper. Fine dust is adsorbed on the outside wall of the filter bag under the suction of the fan. As time goes on, the accumulated dust becomes thicker and thicker, the resistance of the dust collector increases gradually.
When the resistance of the dust collector reaches the set value of pressure difference, the pulse controller starts to instruct the pulse valve to work, the nozzle starts to inject, so that the filter bag can be regenerated, and enters the next filtering process.
The dust blown back into the dust bucket by gravity, and passes through the drainage. Grey valve discharge.
At ordinary times, no matter whether the pressure difference exceeds the limit or not, thermostatic element the injection controller will circulate according to the injection settings to make the filter bag shrink – expand – shrink repeatedly, and gradually remove the dust adsorbed on the outer wall of the filter bag, fall into the ash hopper, and then discharge by the dust discharge valve. Nowadays, the injection controller can not directly help the operator to monitor the dust removal system in real time, and the display value sometimes can not meet the actual situation. Each dust removal system corresponds to different cigarette machine equipment, and the working state of the cigarette machine equipment for a period of time is not the same. It is necessary to reset the parameters according to the actual situation. But now all the values of the controller, including the display of fault information, are coded, and need to be set against the instructions, resulting in low work efficiency. During the operation of the dust removal system, there is often a phenomenon that the dust removal bags are knotted. Especially after holidays, it is necessary to remove and clean the dust removal bags manually, resulting in the suspension of the operation of the dust removal system. According to the statistical table of the replacement of the electrical components of the injection controller in the previous year, it can be seen that the frequency of the replacement of the power supply of the controller, Darlington tube and the main control board is the highest.
From the analysis of the current situation, the main defects of the pulse injection flat bag filter controller are: it can not effectively monitor the real-time, the parameters and fault information are all code display, it is easy to appear dust bag knot, electrical components failure frequently. The display screen not only displays mixed numbers of code, but sometimes the values are different from the actual ones. The content presented on the smaller screen is limited, so it needs to be flipped for viewing.
Through observation, it is found that the compressed air of dust cleaning is colder, the dust removal system works in a high temperature environment, sometimes the external environment temperature is too high, resulting in moisture on the surface of the dust bag, and the adherent dust is easy to form coagulation. Nowadays, the injection controller is the main control board made by single-chip computer. However, the single-chip computer is easily affected by the working environment, layout structure and other factors, resulting in poor anti-interference ability, high failure rate, and is not easy to meet the expansion needs. The inner part of the Darlington tube is composed of several tubes and resistors. It runs in high temperature, dust and high vibration environment, which easily leads to frequent failure of the Darlington tube. The former be junction is also connected with an input diode in reverse parallel.
It is found that the forward and reverse resistance values of the be junction are very close, and it is easy to misjudge. From the current controller, it can be seen that the control box is not tightly sealed, dust often enters, and the power supply is easy to absorb dust, resulting in power failure. Through the analysis of the defects of the pulse injection flat bag dust collector, the upgrading idea and the direction of improvement are clarified.
The effective control and real-time monitoring of the injection function will be realized through the combination of hardware and software. In view of the reasons for the above problems, a new injection controller is proposed based on the original system to ensure the effective injection of the system, while greatly reducing the system failure rate and maintenance time.
According to the above countermeasures (as shown in Table 2), we choose Gumei Text Integrative PLC as the new injection controller. The model is EX2N-25MR-40B-3AD-2V1NTC10K-S core controller main frame, which meets the requirements of countermeasures. Firstly, the machine integrates logic control, analog input and output, HMI, LCD display 192*64 pixels, can clearly display 6 lines*16 Chinese characters, two 10KAB high-speed counts, two 20K high-speed pulses; secondly, the machine provides 232 programming ports, PLC422 programming ports, 485 communication ports, and can support MODBU communication protocol, including host, slave mode, can be networked with multiple PLCs or other devices, edit simplified. It is simple, intuitive and rich in functions. It meets the requirement of adding peripheral pressure difference sensor and temperature sensor to realize effective control of injection function and room temperature monitoring. It also has 25 switch input and output points, and meets the requirement of installing more than 20 injection relays. Finally, it meets the requirement of IP65 for waterproof and dust-proof. The main frame of the new controller is selected and programmed according to the requirements. Firstly, according to the working environment, working requirements and equipment status, the appropriate injection time, injection interval and differential pressure action limit are set and the appropriate working mode items are selected.
Under the control of the working procedure, the controller is required to issue instructions to each solenoid valve according to the setting requirements, and open each solenoid valve in turn, and sequentially to each group of filter bags. High-pressure air is injected inside to accomplish the tasks of filtration, purification and dust removal. Secondly, the temperature sensor and pressure sensor are loaded into the controller, and the real-time display of working mode, ambient temperature and real-time pressure difference, as well as the working status of each solenoid valve on the LCD screen according to the working conditions on site, provides the necessary basis for maintenance and repair. After retrofitting the injection controller, the frequency of faults in one year was reduced from 28 times to 3 times, which affected the shutdown of single cigarette machine from 4 times to 1 time.
No one time in the whole year resulted in the shutdown of more than 6 units, and only 2 relays were replaced by electrical components. Effectively improve the failure rate of the dust removal and injection controller, and intuitively provide prompts and guidance for operators and repairmen. Based on the working status of the existing flue gas machine equipment, the working requirements of dust removal and the working environment, we upgraded and reformed the injection controller in terms of electronic control, program and so on. The new injection control system has compact structure, stable operation, convenient installation and maintenance, and can effectively improve work efficiency.
The new system is superior to the old injection control system in terms of stability, failure rate and function. The effect of this transformation is obvious and the expected goal has been achieved.