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为及时监测大豆预处理车间刮板输送机在生产中出现的断链、脱链等故障问题，保障刮板输送机的设备安全，分析了刮板输送机断链、脱链的故障原因，并提出了将刮板断链保护器应用于刮板输送机中。刮板断链保护器由速度传感器与信号处理器组成，当刮板输送机出现断链、脱链故障时，速度传感器所传输的脉冲信号频率会下降，信号处理器通过检测脉冲信号频率快速有效地作出反应，快速停机并发出声光报警，保障设备和生产安全。断链保护器结构简单，安装方便，并且不影响刮板输送机的正常运行，适合应用于一些传统企业中。In order to timely monitor broken chain, chain loss and other failure problems in the production of scraper conveyor in the soybean pretreatment workshop, to ensure the equipment safety of the scraper conveyor, the causes of the failure of the scraper conveyor broken chain and chain loss were analyzed, and the application of scraper broken chain protector to the scraper conveyor was put forward. Scraper broken chain protector consists of speed sensor and signal processor. When the scraper conveyor appears broken chain or chain loss failure, the frequency of the plulses transmitted by the speed sensor decreases, and the signal processor can quickly and effectively respond to the rapid shutdown and sound and light alarm by detecting the pluse frequency to protect the equipment and production safety. Broken chain protector is simple in structure, easy to install, and does not affect the normal operation of the scraper conveyor, suitable for application in some traditional enterprises.

石蜡加热器是浸出车间石蜡尾气回收工艺中的重要设备，石蜡加热器温度闭环系统是典型的非线性、时变、不确定性系统，难以建立精确的数学模型。为提高石蜡加热器电动调节阀温度闭环控制效果，以检测石蜡加热器的温度偏差（e）和温度偏差变化率（ec）为输入，模糊PID控制器的KP、KI、KD为输出，构造了二输入三输出的模糊PID控制器。以西门子S7-300 PLC为下位机，WINCC组态软件为上位机，采用STEP 7软件编写模糊PID控制的算法程序，并将程序下载到S7-300 PLC存储卡中,利用S7-300 PLC对电动调节阀开度进行调节，从而实现石蜡加热器温度闭环控制。模糊PID控制器应用于浸出车间石蜡加热器温度闭环控制系统可以减少系统超调量，具有响应速度快、稳定性高等优点，提高了石蜡加热器温度闭环控制系统的运行效率。 Paraffin heater is an important equipment of paraffin vent gas recovery process in leaching workshop. The temperature closed-loop system of paraffin heater is a typical nonlinear, time-varying and uncertain system, which is difficult to establish an accurate mathematical model. In order to improve the temperature closed-loop control effect of electric regulating valve of paraffin heater, taking the temperature deviation e and temperature deviation change rate ec of paraffin heater as inputs and KP, KI and KD of fuzzy PID controller as outputs, a two input three output fuzzy PID controller was constructed. Taking Siemens S7-300 PLC as the lower computer and WINCC configuration software as the upper computer, the algorithm program of fuzzy PID control was compiled with STEP 7 software, and the program was downloaded to S7-300 PLC memory card. S7-300 PLC was used to adjust the opening of electric regulating valve, so as to realize the temperature closed-loop control of paraffin heater. The fuzzy PID controller applied to the temperature closed-loop control system of paraffin heater in leaching workshop can reduce the overshoot of the system, and has the advantages of fast response speed and high stability, thus improving the operating efficiency of the temperature closed-loop control system of paraffin heater.

BackgroundTritium leakage is a typical nuclear accident scene, which is harmful to human and environment. Therefore, numerical simulation of tritium leakage is of significance to nuclear accident emergency decision making.PurposeThis study aims at the numerical simulation of high-pressure tritium leakage.MethodsA numerical simulation method based on AN-EOS model was proposed to solve the problem of tritium leakage from high pressure storage vessels. The AN-EOS model embedded into Fluent by user defined functions was used to describe the tritium leakage transient behavior. The leakage process of tritium and variation rule of concentration were simulated in closed and ventilated environment based on Fluent.ResultsThe results show that the concentration of tritium increases rapidly when the leakage occurs. After stopping leakage, the concentration of tritium in a closed environment increases first and then stabilizes, and gradually decreases in ventilated environment.ConclusionsVentilation has a significant effect on the diffusion of tritium gas, which can effectively achieve the purpose of tritium removal.

In order to correct the evaluation distortion caused by the fluctuation of index value in the field of shield tunnel structural health comprehensive evaluation, this paper, with reference to a subway tunnel section project in combination with regular inspection, health monitoring, disease treatment and other relevant measured data, proposes a comprehensive evaluation model of shield tunnel structure health based on the improved variable weight matter element extension model. This model employs the variable weight theory to improve the traditional fixed weight so as to reflect the influence of fluctuation of index value on index weight. The key indexes with significant adverse effects on structural health are identified through sensitivity analysis. The results show that, compared with the traditional method of fixed weight, the model can correct the evaluation distortion caused by fluctuation of index value and had good evaluation effect. As the case indicates, of all ten indexes, the settlement rate, segment error amount, leakage water and vertical curve radius change are the key indexes which pose significant threat to the tunnel structure, and relevant references can be provided for tunnel maintenance in later stage. [ABSTRACT FROM AUTHOR]

Taking the X80 steel used in the second West-East Pipeline Project (WEPP II) as a study object, this paper researched the effects of Cl- and SO42- with different concentration(wt% ) on internal corrosion behavior of X80 pipeline steel in stimulated solution for pigging product, discussed the nternal corrosion mechanism of WEPP II by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) experimental. The results showed that, in the stimulated solution only conaining different Cl- mass fraction, the polarization curves of X80 pipeline steel have typical characterstics of active dissolution, the corrosion current density(icorr) and the internal corrosion rate of X80 teel increases along with the increase of Cl- mass fraction; in the stimulated solution containing both 0. 05% Cl- and different SO42- mass fraction, the polarization curves of X80 pipeline steel also have typical characteristics of active dissolution, but the internal corrosion rate firstly increases and then decreases with the increase of SO42- mass fraction. When the mass fraction of SO42- is 0.50%, the icorr reaches the maximum value while polarization resistance reaches the minimum value, and the corrosion behavior of X80 steel is the most serious at this time; when the stimulated solution contain both Cl- and SO42-, the corrosion potential of X80 steel decreases while the icorr increases than the stimulated solution only containing Cl-, with the increase of SO42- mass fraction; when the stimulated solution contain both Cl- and SO42-, with the increase of SO42- mass fraction, SO42- can adsorb on he metal surface faster than Cl-, which decreases the corrosion aroused by Cl-. [ABSTRACT FROM AUTHOR]