Design And Development Of A New Vertical Coal Sampling Mill

In recent years,thermal power generation has brought great economic benefits to the society and the country,and the quality of coal directly affects the efficiency of power generation.In the feeding stage of thermal power combustion system,the sampling system can provide reliable coal detection samples in time.The quality composition of coal can be obtained through the analysis of samples.According to the coal composition,the operation parameters of boiler can be adjusted to improve the utilization rate of coal for thermal power generation,so as to reduce environmental pollution.Therefore,the sampling system also plays an important role in high-quality power generation.As the core equipment of the sampling system,the coal sampling crusher realizes the automatic random sampling and sample preparation of the whole section of coal flow,eliminates the interference of human factors,and provides a reliable means for the modern management of enterprises.However,under the high-speed operation,the traditional horizontal hammer coal sampling pulverizer generally has the defects of low efficiency and easy to block coal,so it is urgent to design a new type of coal sampling pulverizer to solve the above problems.Aiming at the problems of traditional horizontal hammer coal sampling pulverizer in the process of operation,firstly,based on the crushing theory of the pulverizer,the overall structure of the new coal sampling pulverizer is designed and analyzed.According to the moisture and crushing state of coal,the overall design scheme of the new coal sampling pulverizer is determined.The design scheme of vertical rotor structure and symmetrical arrangement of multi-layer oblique cutting knives is determined.Through the mechanical characteristics of the mechanical structure,the design of the main parts of the pulverizer,such as the spindle,cutter head,oblique cutting knife and cutter shaft,is completed.Secondly,the main parts of the rotor system of the new coal sampling pulverizer are modeled by using the Computer-Aided Design Software Solidworks,the main parts are matched,and the assembly drawing of the rotor system of the pulverizer is generated.Based on the statics theory,the strength and stiffness of cutter shaft and spindle are analyzed by using ANSYS Workbench software,and the equivalent cloud images of cutter shaft and spindle are generated;According to the linear vibration theory,the modal analysis of different diameter of the main shaft of the grinder is carried out,and the natural frequency obtained from the modal analysis is studied to prevent the resonance of the main shaft under the action of external force,so as to avoid the damage of the structure of the main shaft of the grinder;At the same time,the modal analysis of the cutter head on the rotor of the coal sampling pulverizer is carried out.By studying the first six modal nephogram of the cutter head,it is verified that the resonance phenomenon will not occur in the working process of the cutter head.Finally,through the research and analysis of the mechanical properties of the new coal sample crusher,the test prototype is built,and the crushing test is carried out with different spindle speeds.Through the research and analysis of the test results,it is determined that when the spindle speed n = 1160 r / min,there is no coal blocking phenomenon,the crushing particle size qualified rate is the highest,and the production capacity is the largest,The rationality of the design is verified.The new type of coal sampling pulverizer studied in this paper is a vertical rotor type pulverizing equipment,which has the advantages of high crushing efficiency and stable work,and can avoid and improve the defects of low efficiency and easy coal blocking in the operation process of traditional horizontal hammer coal sampling pulverizer.The design and development of new coal sampling pulverizer enrich the design theory of crushing equipment in power industry,and has a certain guiding value.