Calculation And Research For Roller Pressure Of Roller Mills

Roller mills as a kind of processing equipment which make power grinding with the theory of crushing on the material bedding can be widely used in power engineering. Compared with traditional ball mills, roller mills have many advantages. Therefore, since the 1970s, roller mills begin to instead of ball mills in cement industry and become the lead system for grinding cement raw material. With the fast development of global economy and the continuous emergence of new technology, the growth of roller mills become even more rapidly and the enlargement of equipment will be the main development tendency in future.The reliability of large grinding equipment is a key problem to the design in which grinding pressure is a considerable principal element. Therefore, the research of grinding pressure has a significant meaning to the roller mills design.Because the contact situation between grinding roller of roller mills and the materiel is so complex that the actual grinding pressure of roller mills which is generally represented in traditional grinding pressure is hard to calculate accurately. But the contact surface between grinding roller and the materiel used by traditional grinding pressure is simplified to the surface or projecting plane of grinding roller that can't reflect the truth and cause obvious calculation errors. In order to improve the calculation precision of grinding pressure, a new calculation of grinding pressure for roller mills named mean curved grinding pressure computing method is presented in this paper.At first, the most representative vertical roller mill called Loesche is selected as an object to establishing the static analytical mechanical model of roller mills by analyzing the structure characteristics, technical condition and working principle of several typical roller mills. Than the static analytical mechanical model is built from three aspects, namely, the hydraulic system pressure, contact surface between grinding roller and the materiel and stress state of grinding roller with combining the characteristics of Loesche and the general calculating formula of mean curved grinding pressure is deduced by the curved surface integral, and results are obtained through the calculation of real samples by the procedure of MATLAB. Than the correctness and accuracy of this new method are validated by comparing the results separately calculated by mean curved grinding pressure computing method and traditional grinding pressure computing method in three different views namely the value of grinding pressure, stress and strain of main stress parts in roller mills and mill power and probing decisive factors of numerator and denominator in the computing formula and analyzing the influences of design parameters on the calculating result based on the formula of mean curved grinding pressure. The calculation analysis shows that this method is accurate and more closed to the realistic grinding pressure of roller mills than traditional grinding pressure, which provides references for the selection of design parameters and the design calculation of structural strength of roller mills.