heavy rotors carrying fastened projections revolve inside a casing。 The projection breaks the rock by primary impact and propels the rock against the case where it is broken by secondary impact。 Hammer mills are similar to impact breakers except hammers are pivoted on rotor and usually only one rotor is used。 They may have a great difference at the discharge, the spacing of which determines the product size。 Feeder breakers are utilized in soft applications to medium hard applications when the requirement is to coarsely break material for belt conveying, frequently used for overburden and underground duty
5 Using fuzzy TOPSIS method to primary crusher selection The hierarchical structure of the problem is shown in Fig。 3。 The fuzzy TOPSIS method is applied to solve this problem。 The decision makers use the linguistic variables to evaluate the importance of attributes and the ratings of alternatives with respect for various attributes。 In this work, to select the suitable primary crusher for studied mine, in order to illustrate the idea of fuzzy MCDM, we deliberately transform the existing precise values to seven-levels, fuzzy linguistic variables; very low (VL), low (L), middle Low (ML), middle (M), middle high (MH), high (H) and very high (VH), where VL=(0, 0, 1), L=(0, 1, 3), ML=(1, 3, 5), M=(3, 5, 7), MH=(5, 7, 9), H=(7, 9, 10) and VH=(9, 10, 10)。 Among the commonly used fuzzy numbers, triangular and trapezoidal fuzzy numbers are likely to be the most adoptive ones, due to their simplicity in modeling and easy of interpretation。 Both triangular and trapezoidal fuzzy numbers are applicable to the present study。 We feel that a triangular fuzzy number can adequately represent the seven-level fuzzy linguistic variables which used for the analysis hereafter。Ratings and weights of primary crusher selection by three experts (D1, D2 and D3) under six criteria for the eight crushers are presented in Table 4。 The fuzzy linguistic variables are then transformed into a fuzzy triangular membership function, as shown in Table 5。 This is the first step of the fuzzy TOPSIS analysis。 The second step in the analysis is to find the weighted fuzzy decision matrix。 The normalized fuzzy decision matrix is formed in Table 6。 Then weighted normalized fuzzy decision matrix is formed in Table 7。 According to Table 4, we can define the fuzzy positive-ideal solution (FPIS, A*) and the fuzzy negative-ideal solution (FNIS, A−)。 This is the third step of the fuzzy TOPSIS analysis。 The results of all alternatives distances from FPIS and FNIS are listed in Table 8。 For the fourth step, the distance of each alternative from A* and A− can be calculated using (6)。 The results of all alternatives distances from FPIS and FNIS are listed in Table 9。 For example: According to the closeness coefficient of eight alternatives, the order of these alternatives is A1>A7>A4> A3A6>A8>A2>A5。 Gyratory primary crusher is selected as its closeness coefficient has the highest value。 In other words, the first alternative is closer to the FPIS andfarther from the FNIS。 模糊TOPSIS方法对初级破碎机英文文献和中文翻译(4):http://www.youerw.com/fanyi/lunwen_92562.html