标准编号:	GB/T 36698-2018
中文名称:	带式输送机设计计算方法
英文名称:	Basis for calculation of belt conveyors
中标分类:	J81    输送机械
行业分类:	GB    国家标准
ICS分类:	53.040.10 53.040.10    输送机 53.040.10
发布机构:	国家市场监督管理总局 国家标准化管理委员会
发布日期:	2018-09-17
实施日期:	2019-4-1
标准状态:	valid
翻译语言:	英文
文件格式:	PDF
中文字符数:	54000 字
翻译价格(元):	3780.0
交付时间:	付款后 1 个工作日

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative. This standard is developed in accordance with the rules given in GB/T 1.1-2009. This standard was proposed by China Machinery Industry Federation. This standard is under the jurisdiction of National Technical Committee 331 on Continuous Handling Equipment of Standardization Administration of China (SAC/TC 331). Basis for calculation of belt conveyors 1 Scope This standard specifies the basis for design calculation of belt conveyors, which is used to determine the basic parameters and layout design of their main components (such as driving unit, braking unit, take-up unit, pulley, idler and conveyor belt). This standard is applicable to belt conveyors used for conveying bulk materials. This standard is not applicable to the basis for design calculation of special belt conveyors such as cable, pipe and air cushion belt conveyors. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 7984 Conveyor belts of textile construction for general use GB/T 9770 Steel cord conveyor belts for general use GB/T 10595 Belt conveyors GB/T 14521 Terms of continuous handling equipment GB/T 28267.1-2012 Steel cord conveyor belts - Part 1: Design, dimensions and mechanical requirements for conveyor belts for general use GB/T 28267.2 Steel cord conveyor belts - Part 2: Preferred belt types GB/T 28267.3 Steel cord conveyor belts - Part 3: Special safety requirements for belts for use in underground installations GB/T 28267.4 Steel cord conveyor belts - Part 4: Vulcanized belt joints GB/T 31256 Conveyor belts - Specification for rubber- or plastics-covered conveyor belts of textile construction for underground mining GB 50431 Code for design of belt conveyor engineering 3 Terms and definitions For the purposes of this document, the terms and definitions given in GB/T 14521 and the following apply. 3.1 starting for inherent characteristics mode where the belt conveyor is started according to the inherent mechanical characteristics (relationship between rotational speed and torque) of driving unit 3.2 starting for motion control starting mode where the belt conveyor is controlled according to the set starting acceleration or speed curve 3.3 nominal capacity conveying capacity used for belt conveyor design according to the requirements of engineering design 4 Symbols, definitions and units Symbols, definitions and units are given in Table 1. Table 1 Symbols, definitions and units Symbol Definition Unit A Cross-sectional area of carried materials m2 A1 Cross-sectional area of the upper part of carried materials m2 (mm2)a A2 Cross-sectional area of carried materials when θ = 0° (cross-sectional area of lower part of carried materials) (3-roller idler set) Cross-sectional area of inverted trapezoidal part on outer roller (5-roller idler set) m2 (mm2)a A3 Cross-sectional area of inverted trapezoidal part on inner roller (5-roller idler set) m2 (mm2)a AN Cross-sectional area of carried materials under nominal capacity m2 AGr Effective contact area between the working face cleaner and the conveyor belt mm2 AGr1 Effective contact area between the non-working face cleaner and the conveyor belt mm2 B Belt width mm C Additional resistance coefficient — D Diameter of pulley mm D1 Datum diameter of pulley determined according to the service life conditions of the conveyor belt mm ELB Longitudinal elastic modulus of the conveyor belt N/mm F Tension or resistance of the conveyor belt N Fa Inertial force caused by acceleration/deceleration under unsteady operating condition N FbA Inertial resistance of conveyed materials and/or frictional resistance between conveyed materials and the conveyor belt in feeding section N Fc1 Conveyor belt tension at the start point of convex or concave curved section N Fc2 Conveyor belt tension at the end point of convex or concave curved section N FD Average tension of conveyor belt on the pulley N FE Indentation rolling resistance per unit length obtained based on the test results N/m Ff Frictional resistance between the conveyed materials and the side plates of the skirt board in feeding section N FH Major resistance N Fgl Frictional resistance between the conveyed materials and the side plates of the skirt board outside the feeding section N FHs Locking force N FI Bending resistance of conveyor belt when winding the pulley N Fr Frictional resistance of the working surface cleaner N Frl Frictional resistance of non-working face cleaner N FN Additional resistance N Fp Frictional resistance of the tripper N FR Rotating resistance of idler per unit length obtained based on the test results N/m FS Special resistance N Fsbn Frictional resistance of buffer bed (sliding bed) N FSk Frictional resistance of apron seal of skirt board in feeding section N FSk1 Frictional resistance of apron seal of skirt board outside the feeding section N FSp Take-up tension of take-up pulley N FSt Lifting resistance of conveyed materials (which includes the lifting resistance of conveyor belt in section resistance calculation) N Fl Pulley bearing resistance N FT Tension of conveyor belt at characteristic point N FT1 Tension at the point of contact between the conveyor belt and the pulley N FT2 Tension at the separation point between the conveyor belt and the pulley N FTm Average tension of the conveyor belt N FTr Peripheral driving force of the pulley N FU Traveling resistance (equal to the peripheral driving force of the pulley) N FV Vector sum (numerical value) of the conveyor belt tension acting on the pulley and the weight of pulley rotor N Fw Additional bending resistance of convex or concave curved section N Ft Forward tilt resistance N ΔFTm The difference between the average conveyor belt tension, FTm, and the minimum conveyor belt tension, FTmin N Im,N Nominal capacity by mass kg/s Im,th Theoretical capacity by mass kg/s IV,N Nominal capacity by volume m3/s IV,th Theoretical capacity by volume m3/s J Moment of inertia of pulley kg·m2 JD Moment of inertia of driving unit rotor on the high-speed shaft of the reducer kg·m2 Jf Moment of inertia of flywheels kg·m2 L Conveyor length m Ka Scraper coefficient N/m PA Total power of driving pulley required to overcome traveling resistance under steady operating condition kW PM Total power of driving motor kW PM,N Rated power of driving motor kW Q Nominal capacity t/h Ra Curvature radius of vertical concave curved section m (mm)a Re Curvature radius of vertical convex curved section m (mm)a S Safety coefficient relative to nominal tensile strength of conveyor belt — S0 Safety coefficient of conveyor belt determined with joint process conditions considered — S1 Safety coefficient determined with expected life and working stress of conveyor belt considered — Smin Minimum safety coefficient relative to the minimum nominal tensile strength of conveyor belt — a Acceleration or deceleration m/s2 b Effective width of conveyor belt (theoretical width of conveyor belt carrying materials) m (mm)a b1 Width of materials stacked on conveyor belt mm b2 Width of materials on 3-roller idler set mm bS Width of conveyor belt on side rollers (only for 2-roller and 3-roller idler sets) mm bSch Clear width between skirt boards m c0 Calculation coefficient used to determine the minimum diameter of pulley — cK Coefficient of minimum joint fatigue strength determined based on edge tension of conveyor belt — cR Calculation coefficient for converting the rotating mass of idler to the equivalent mass on the periphery of the idler — cRank Coefficient of active lateral pressure — cS Speed correction coefficient of simulated friction coefficient — CSchb Coefficient of additional resistance caused by material disturbance in the feeding section — cT Temperature correction coefficient of simulated friction coefficient — cTd Coefficient used to determine the datum value of the minimum length of the troughing transition section — cε Calculation coefficient of forward tilt resistance — d0 Inner diameter of pulley bearing mm dB Thickness of tensile element (core) of conveyor belt (excluding the upper and lower coatings of conveyor belt) mm dR Diameter of idler m e The napierian base (e=2.718 28…) — eK Height difference from neutral datum line to the edge of conveyor belt mm eM Height difference from the neutral datum line to the center of the conveyor belt mm fbase Datum value of simulated friction coefficient — Δfs Correction of simulated friction coefficient related to belt speed — ΔfT Correction of simulated friction coefficient related to temperature — f Simulated friction coefficient — fi Simulated friction coefficient for each section of the upper and lower branches — fr Rotating frequency of rollers in an idler set at a certain belt speed Hz fp Approximate inherent vibration frequency of cross-sectional of conveyor belt Hz fRMBT Pulley load factor (determined by the maximum tension and nominal tensile strength of conveyor belt) — g Gravitational acceleration (g=9.81 m/s2) m/s2 h Height difference (h > 0 in upward case; h<0 in downward case) m hk0 Distance from the plane formed by the edges of both sides of the conveyor belt to the lowest plane of the trough m hk1 Distance between the plane formed by the edges of both sides of the conveyor belt and the upper generatrix plane of the pulley m hTr Distance between the upper generatrix plane of the pulley in the troughing transition section and the lowest plane of the trough (the height of pulley elevation) m i Drive ratio — k Conveyor belt tension relative to conveyor belt width (average conveyor belt tension over belt width) N/mm kK Tension per unit width at the edge of conveyor belt N/mm kM Tension per unit width in the central area of the conveyor belt N/mm kN Nominal tensile strength of conveyor belt N/mm kN,min Minimum nominal tensile strength of conveyor belt N/mm hrel Sag of conveyor belt (ratio of the maximum sagging amount of conveyor belt between idler sets to the spacing between idler sets) — kt Datum fatigue strength of conveyor belt joint (tensile strength of conveyor belt with strength reduction of conveyor belt joint considered) N/mm kt,rel Relative datum fatigue strength of conveyor belt joint — Δk Difference in tension per unit belt width between the edge and the central area of the conveyor belt N/mm l Length of section m l2 Length of 2 middle rollers (5-roller idler set) mm lb Length of the skirt board in the feeding section m lgl Length of the skirt board outside the feeding section m lK Edge length of conveyor belt in troughing transition section m lM Length of the middle idler of 3-roller idler set mm (m)a lR Spacing between idler sets m ls1 Contact length between outer idlers and materials m lTd Length of troughing transition section m lTd,eff Effective length of troughing transition section of steel cord conveyor belt m ΔlTd Additional length of transition section, namely, lTd,eff-lTd of steel cord conveyor belt m lw Length of turnover section of the conveyor belt m mf Equivalent mass of flywheel converted to the periphery of the pulley kg mD Equivalent mass of the pulley, flywheel (if set), driving and braking units converted to the periphery of the pulley kg mL Equivalent mass of conveyor belt, material and idler on belt conveyor line kg ∑m Sum of equivalent mass of conveyor belt, material and idler on belt conveyor line and equivalent mass of pulley, driving and braking units on belt conveyor line converted to the periphery of the pulley kg n Number of sections of belt conveyor divided — nR Maximum allowable rotating speed of roller under steady operating condition of belt conveyor r/min pA Starting coefficient related to driving pulley — pA,0 Starting coefficient related to driving — pB Braking coefficient related to braking pulley — pB,0 Braking coefficient related to braking — pD Power distribution coefficient — pGr Pressure exerted by the working face cleaner on the conveyor belt N/mm2 pGr1 pressure exerted by the non-working face cleaner on the conveyor belt N/mm2 pSk Effective positive pressure per unit length between conveyor belt and seal N/m pBp Allowable specific pressure of the conveyor belt N/mm2 pBs Allowable specific pressure under the steel wire rope of steel cord conveyor belt N/mm2 q Coefficient of estimation of major resistance — qB Mass per unit length of conveyor belt kg/m qR Mass per unit length of idler rotor kg/m qG,i Mass per unit length of material on a section kg/m s1 Thickness of conveyor belt mm sSp Working distance of take-up pulley m v Belt speed m/s v0 Speed of the material fed to the conveyor belt in the conveying direction m/s sB Braking distance m t1 Spacing between steel wire ropes of conveyor belt mm tB Braking time s zD Number of driving or braking pulley Pcs. zM Number of motors (driving units) Pcs. zR Number of idler sets on a section (in upper or lower branch) Set zTr Number of pulleys Pcs. zε Number of forward tilting idler sets on a section (in upper or lower branch) Set α Wrap angle ° or rad αc Central angle corresponding to the convex or concave curved section rad β Equivalent angle of move of materials used to calculate the cross-sectional area of materials ° θ Angle of move (angle of repose) of conveyed materials ° δ Conveying angle of inclination (δ>0 in upward case and δ<0 in downward case) ° ε Angle of inclination of side roller (top rake) ° φ Effective filling coefficient — φSt Cross-sectional reduction coefficient of theoretical total carrying cross-sectional area during inclined conveying — φSt1 Cross-sectional reduction coefficient of theoretical cross-sectional area of the upper part of carried materials during inclined conveying — λ Trough angle of idler set and outer roller (4-roller and 5-roller idler sets) ° λ1 Trough angle of 2 middle rollers (4-roller and 5-roller idler sets) ° μ Friction coefficient between conveyor belt and pulley — μ1 Friction coefficient between conveyor belt and conveyed material — μ2 Friction coefficient between the conveyed materials and the side plates of the skirt board — μ3 Friction coefficient between conveyor belt and idlers — μ4 Friction coefficient between conveyor belt and cleaner — μ5 Sliding friction coefficient between conveyor belt and sealing rubber — μ6 Friction coefficient between buffer bed and conveyor belt — ρ Bulk density of conveyed materials kg/m3 ΔεK Additional elongation (positive or negative) at the edge of conveyor belt relative to natural axial concave or convex curved section of conveyor belt — ΔεK∞ The limit value of ΔεK at the edge of conveyor belt with long curved section — ΔεM Additional elongation (positive or negative) at the central area of conveyor belt relative to natural axial concave or convex curved section of conveyor belt — ΔεM∞ The limit value of ΔεM at the central area of conveyor belt with long curved section — Δε∞ Difference in elongation between the central area and the edge of the conveyor belt with long curved section — η1 Total efficiency of all driving links between motor shaft and pulley shaft in motor mode — η2 Total efficiency of all driving links between motor shaft and pulley shaft in generator mode a Units in brackets are used in some formulae.   5 Capacity by volume and by mass 5.1 Theoretical cross-sectional area of materials The theoretical capacity by volume and by mass of belt conveyor are determined by the theoretical cross-sectional area and traveling speed of materials stacking on the conveyor belt. The cross-sectional area of materials depends on the angle of move of the conveyed materials, the specific structural type of the idler set and the feeding mode. In calculating the theoretical capacity by volume and by mass, this standard assumes that the cross section of the conveyed materials has upper surface with parabolic contour line. Figure 1 shows a cross section of materials on the supporting conveyor belt of a common troughing 3-roller idler set. Figure 1 Theoretical cross section of horizontally-carried materials conveyed by 3-roller idler set The theoretical cross-sectional area of carried materials is determined by the length, lM, of middle roller, the trough angle, λ, the effective width, b, of the conveyor belt, and the angle of move, θ. The effective width, b, is the width of the conveyor belt with a certain margin reserved to avoid spillage; it can be calculated using Formulae (1) and (2): b=0.9B-50 (if B≤2,000) (1) b=B-250 (if B>2,000) (2) where, B——the belt width, mm; b——the effective width of conveyor belt (theoretical width of conveyor belt carrying materials), mm. As for the belt conveyor with horizontal curves, the effective width of the conveyor belt may be reduced due to the inclined arrangement of rollers. As for the materials carried by supporting conveyor belt of 3-roller idler set on a horizontally-arranged belt conveyor, the theoretical cross-sectional area, Ath, calculated based on the angle of move θ may be determined based on the sum of cross-sectional areas, A1,th and A2,th, (see Figure 1); Formulae (3), (4) and (5) shall be used for calculation: (3) (4) Ath=A1,th+A2,th (5) where, Ath——the theoretical cross-sectional area of carried materials, m2; A1,th——the theoretical cross-sectional area of the upper part of carried materials, m2; A2,th——the theoretical cross-sectional area of carried materials when θ = 0° (cross-sectional area of lower part of carried materials), m2; lM——the length of the middle idler of 3-roller idler set, m; θ——the angle of move of materials, °; λ——the trough angle of idler set, °; b——the effective width of conveyor belt (theoretical width of conveyor belt carrying materials), m. When used to calculate the cross-sectional area A1,th, the equivalent angle of move β shall be calculated using Formula (6): (6) where, β=θ/1.5. The angle of move of materials depends on the characteristics of conveyed materials and factors of belt conveyors, such as length and belt speed. If empirical value of angle of move is not available, the following may be chosen: ——for materials with normal fluidity, take 0≤θ≤20°; ——for materials with high fluidity, take 20°≤θ≤30°. Theoretical cross-sectional area of materials carried by 2-roller idler set shall be calculated by substituting lM=0 into Formulae (3) and (4); Theoretical cross-sectional area of materials carried by 1-roller idler set shall be calculated by substituting lM=0 and λ=0 into Formulae (3) and (4). See Annex A for the calculation of the theoretical cross-sectional area, Ath, of materials carried by 1-roller, 2-roller, 4-roller and 5-roller idler sets respectively. Theoretical capacity by volume shall be calculated using Formula (7) based on the theoretical cross-sectional area of carried materials: IV,th=Ath·v (7) Theoretical capacity by mass shall be calculated using Formula (8): Im,th=ρAth·v (8) where, IV,th——the theoretical capacity by volume, m3/s; Im,th——the theoretical capacity by mass, kg/s; v——the belt speed, m/s; ρ——the bulk density of conveyed materials, kg/m3. 5.2 Cross-sectional reduction coefficient during inclined conveying When a belt conveyor feeds uniformly and travels horizontally and straightly, its theoretical cross section of materials can be fully utilized.   Under the influence of material weight, internal friction angle and other factors, the area of the upper part, A1,th, shown in Figure 1 will be reduced. When the belt conveyor is well centered, uniformly feeds and conveys materials with small particle size and the maximum angle of inclination, δmax on the belt conveyor line ≤θ, the reduction coefficient of the upper part shall be calculated using Formula (9): (9) where, φSt1——the cross-sectional reduction coefficient of theoretical cross-sectional area, A1,th, of the upper part of carried materials during inclined conveying, dimensionless; δmax——the maximum angle of inclination on the belt conveyor line, °; θ——the same as that in Formula (3). The reduction coefficient, φSt, of theoretical cross-sectional area of carried materials during inclined conveying shall be calculated using Formula (10): (10) where, φSt——the cross-sectional reduction coefficient of theoretical cross-sectional area, Ath, of the carried materials during inclined conveying, dimensionless. If Formulae (9) and (10) are used, attention shall be paid to that the maximum angle of inclination during inclined conveying can only be equal to the angle of move, θ. In this case, only cross-sectional areas A2,th is used for material conveying. 5.3 Nominal capacity and effective filling coefficient When nominal capacity by mass, Im,N, is given, nominal capacity by volume, IV,N, shall be calculated using Formula (11): (11) where: Im,N——the nominal capacity by mass, kg/s; IV,N——the nominal capacity by volume, m3/s. The cross-sectional area required shall be calculated using Formula (12): (12) where: AN——the cross-sectional area of carried materials required under nominal capacity, m2. The effective filling coefficient of belt conveyor shall be calculated using Formula (13): (13) where: φ——the effective filling coefficient of belt conveyor, dimensionless. The effective filling coefficient φ depends on: ——characteristics of conveyed materials; ——particle size and composition; ——angle of move θ; ——operating conditions of belt conveyor; ——uniformity of feeding; ——line layout of conveyor; ——conveying angle of inclination; ——reserve of conveying capacity. The effective filling coefficient, φ, is used to evaluate whether the theoretical sectional area, Ath, of materials matches with the sectional area required under nominal capacity. In this standard, some calculation parameters are selected on premise that the effective filling coefficient φ satisfies 0.7<φ<1.1; otherwise, the calculation parameters selected shall be corrected; in some cases, the effective filling coefficient will be out of the above range, in which the specific values will be determined based on the test data and the experience of the engineer. The mass per unit length of materials under nominal capacity shall be calculated using Formula (14): or qG=φρAth (14) where, qG——the mass per unit length of materials under nominal capacity, kg/m. Nominal capacity shall be calculated using Formula (15): (15) where, Q——the nominal capacity, t/h. 6 Traveling resistance and power consumption under steady operating condition 6.1 Calculation principle As a general rule, before calculating the traveling resistance, it needs to estimate the datum values of the parameters used (such as mass per unit length and simulated friction coefficient of conveyor belt and idler). These values shall be confirmed or corrected according to actual selection during calculation. In general, repeated calculations shall be carried out to achieve calculation results that are completely applicable to specific applications. The traveling resistance, FU, generated under steady operating condition is the total resistance generated by friction, gravity and other resistances together. The power, PA, required by the driving pulley of the belt conveyor is obtained by multiplying the sum of traveling resistances generated by the upper and lower branches by the traveling speed, v, as shown in Formula (16): (16) where, PA——total power on periphery of driving pulley required to overcome traveling resistance under steady operating condition, kW; FU——the sum of traveling resistances generated by the upper and lower branches, N. For the purpose of calculation, the traveling resistances of belt conveyor are classified into: ——major resistance FH (see 6.2); ——additional resistance FN (see 6.3); ——lifting resistance FSt (see 6.4); ——special resistance FS (see 6.5). The sum, FU, of traveling resistances is equal to the peripheral driving force, FTr, of pulley transmitted from the driving pulley to the conveyor belt, as shown in Formula (17): (17) where, FTr——the sum of peripheral driving force of pulley, N; FU,o,i, FU,u,i——the traveling resistance on sections i of the upper and lower branches respectively, N; no, nu——the number of sections divided in upper and lower branches respectively.   Resistance shall be determined by section. The sectioning principle is to have the same calculation parameters in each section, such as the angle of inclination δi, the simulated friction coefficient, fi, the mass per unit length of materials, qG,i, and the mass per unit length of the idler rotor, qR,i, on each section in the upper and lower branches of the belt conveyor. To facilitate computer programming calculation, during the resistance calculation, the sections shall be numbered from the tail section to the head section of the belt conveyor, with subscripted i as the serial number of the section, the subscripted o as the upper branch and the subscripted u as the lower branch (see Figure 2), and pulley numbered as separate section. In the text below, for the sake of uniform expression, the pulley number is indicated by subscripted j, and the point of contact by subscripted T1 and the separation point by subscripted T2. (See Figures 5 and 6). 6.2 Major resistance 6.2.1 Calculation of major resistance The major resistance is generated over the entire length of the conveying lines of all belt conveyors. It includes rotating resistance of idler, indentation rolling resistance of conveyor belt, bending resistance of conveyor belt and internal friction resistance of materials. The major resistance shall be calculated separately for each section. In order to simplify the calculation of section resistance, the major resistance FH,i in each section of upper and lower branches shall be calculated based on the linear relationship between resistance and motion load, as shown in Formula (18): FH,i=lifig[qR,i+(qB+qG,i)cosδi] (18) where, FH,i——the major resistance on section i, N; li——the length on section i, N; fi——the simulated friction coefficient on section i, dimensionless; qR,i——the mass per unit length of the idler rotor on section i, kg/m; qB——the mass per unit length of conveyor belt, kg/m; qG,i——the mass per unit length of materials on section i, kg/m; δi——the conveying angle of inclination of section i, °; g——the gravitational acceleration, m/s2. To determine the conveyor belt tension, the major resistances, FH,o,i and FH,u,i, in sections of upper and lower branches respectively must be determined firstly (see 8.3). The major resistance of a belt conveyor is the sum of the major resistances, FH,o and FH,u, of upper and lower branches, as shown in Formula (19): (19) where: FH——the total major resistance of upper and lower branches, N; FH,o,i, FH,u,i——the major resistance on sections i of the upper and lower branches respectively, N; FH,o, FH,u——the sum of the major resistances of upper and lower branches respectively, N. Key: 0, 1, 2——characteristic points of conveyor line; lo,1, lo,2, lu,1, lu2——the lengths of sections 1 and 2 of upper branch and lower branch, respectively; FU,o,1, FU,o,2, FU,u,1, FU, u,2——the traveling resistance of sections 1 and 2 of upper and lower branches, respectively. Figure 2 Section division and traveling resistance of each section under steady operating condition In calculating the major resistance of each section, the effective filling coefficient, φ, of materials shall satisfy 0.7<φ<1.1. Otherwise, the datum values of calculation parameters given in this standard shall be corrected. The major resistance shall be calculated under extreme load conditions (nonuniform feeding, partial load and no load) if upward and downward sections are included on the line of belt conveyor, because the sum of resistances in this case may greatly exceed the resistance under steady operating condition. 6.2.2 Determination of simulated friction coefficient Choosing the simulated friction coefficient fi is more important than calculating the major resistance, because fi determines the major resistance, especially for belt conveyors with small lifting resistance. The simulated friction coefficient fi given in Table 2 may be used to calculate the major resistance of upper and lower branches. If measured or empirical value is unavailable, or only rough equipment parameters are available, the datum value of the simulated friction coefficient f may be selected according to the operating condition and structural characteristics given in Table 2. These datum values are obtained by summary based on a large number of measurements on the upper and lower branches and with the following restrictions considered:

Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Symbols, definitions and units 5 Capacity by volume and by mass 5.1 Theoretical cross-sectional area of materials 5.2 Cross-sectional reduction coefficient during inclined conveying 5.3 Nominal capacity and effective filling coefficient 6 Traveling resistance and power consumption under steady operating condition 6.1 Calculation principle 6.2 Major resistance 6.3 Additional resistance 6.4 Lifting resistance 6.5 Special resistance 6.6 Calculation method of total traveling resistance of belt conveyor 7 Design calculation of driving system 7.1 Contents of design calculation 7.2 Position of driving unit, specification and number of driving motor 7.3 Starting, braking and stopping 8 Calculation of tension and take-up tension of conveyor belt 8.1 Factors affecting conveyor belt tension 8.2 Conveyor belt tension 8.3 Traveling resistance and tension at characteristic point of upper and lower branch sections 8.4 Take-up tension and working distance of take up unit 8.5 Tension of conveyor belt at characteristic point of upper and lower branches 9 Tension distribution across the width of conveyor belt 9.1 Calculation principle 9.2 Troughing transition section 9.3 Curve section 10 Determination of tensile strength and coating thickness of conveyor belt 10.1 Selection principles 10.2 Calculation of break strength of conveyor belt 10.3 Determination of coating thickness of conveyor belt 11 Method for determination of minimum diameter of pulley 11.1 Principle 11.2 Determination based on the service life of conveyor belt 11.3 Determination based on allowable specific pressure of conveyor belt 12 Selection of idler and design of idler spacing 12.1 Calculation principle 12.2 Determination of roller diameter 12.3 Spacing between idler sets 12.4 Design to avoid resonance 13 Design of curvature radius of troughing transition section and vertical curved section 13.1 Calculation principle 13.2 Determination of minimum length of troughing transition section 13.3 Determination of minimum radius of vertical curved section 14 Design of turnover of the conveyor belt Annex A (Informative) Calculation of cross-sectional area of materials carried by 5-roller idler sets Annex B (Informative) Determination of total additional resistance based on additional resistance coefficient Annex C (Informative) Calculation of maximum conveyor belt tension for simply arranged belt conveyors Bibliography

带式输送机设计计算方法 1 范围 本标准规定了带式输送机的设计计算，用于确定带式输送机主要部件(如驱动装置、制动装置、拉紧装置、滚筒、托辊和输送带等)的基本参数与布置设计。 本标准适用于输送散状物料的带式输送机。 本标准不适用于钢丝绳牵引带式输送机、管状带式输送机、气垫带式输送机等特种带式输送机的设计计算，其通用部分的设计计算可参照使用本标准。 2规范性引用文件 下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本文件。凡是不注日期的引用文件，其最新版本(包括所有的修改单)适用于本文件。 GB/T 7984普通用途织物芯输送带 GB/T 9770 普通用途钢丝绳芯输送带 GB/T 10595 带式输送机 GB/T 14521 连续搬运机械术语 GB/T 28267.1—2012 钢丝绳芯输送带 第1部分：普通用途输送带的设计、尺寸和机械要求 GB/T 28267.2钢丝绳芯输送带 第2部分：优选带型 GB/T 28267.3 钢丝绳芯输送带 第3部分：井下用输送带的特殊安全要求 GB/T 28267.4钢丝绳芯输送带 第4部分：带的硫化接头 GB/T 31256输送带 具有橡胶或塑料覆盖层的地下采矿用织物芯输送带规范 GB 50431 带式输送机工程设计规范 3术语和定义 GB/T 14521界定的以及下列术语和定义适用于本文件。 3.1 固有特性启动starting for inherent characteristics 带式输送机按照驱动装置固有的机械特性(转速和转矩关系)的启动方式。 3.2 运动控制启动starting for motion control 带式输送机按照设定的启动加速度或速度曲线控制的启动方式。 3.3 设计输送量nominal capacity 根据工程设计要求的、用以进行带式输送机设计的输送量。 4符号、含义与单位 表1给出了符号、含义与单位。 表1 符号、含义与单位 符号 含义 单位 A 承载物料的横截面积 m2 A1 承载物料的上部的横截面积 m2(mm2)a A2 当θ=0°时承载物料的截面积(承载物料的下部的横截面积)(3辊托辊组) 外侧辊子上倒梯形部分横截面积(5辊托辊组) m2(mm2)a A3 内侧辊子上倒梯形部分横截面积(5辊托辊组) m2(mm2)a AN 设计输送量下对应的承载物料的横截面积 m2 AGr 工作面清扫器和输送带之间的有效接触面积 mm2 AGr1 非工作面清扫器和输送带之间的有效接触面积 mm2 B 带宽 mm C 附加阻力系数 — D 滚筒直径 mm D1 按输送带使用寿命条件确定的滚筒基准直径 mm ELB 输送带纵向弹性模量 N/mm F 输送带的张力或阻力 N Fa 非稳态运行条件下由加速/减速度产生的惯性力 N FbA 加料段输送物料的惯性阻力和(或)输送物料与输送带间摩擦阻力 N Fd 凸、凹弧曲线段起始点的输送带张力 N Fc2 凸、凹弧曲线段终止点的输送带张力 N FD 滚筒上平均输送带张力 N FE 根据测试结果得出的单位长度压陷滚动阻力 N/m Ff 加料段输送物料与导料槽侧板间的摩擦阻力 N FH 主要阻力 N Fg1 加料段外输送物料与导料槽侧板间的摩擦阻力 N FHs 逆止力 N FI 输送带绕经滚筒的弯曲阻力 N Fr 工作面清扫器的摩擦阻力 N Fr1 非工作面清扫器的摩擦阻力 N FN 附加阻力 N Fp 卸料器的摩擦阻力 N FR 根据测试结果得出的单位长度托辊转动阻力 N/m FS 特种阻力 N Fshn 缓冲床(滑动床)的摩擦阻力 N FSk 加料段导料槽裙板密封的摩擦阻力 N FSk1 加料段外导料槽裙板密封的摩擦阻力 N FAp 拉紧滚筒的拉紧力 N FAt 输送物料的提升阻力(在区段阻力计算中包括输送带的提升阻力) N Ft 滚筒轴承阻力 N FT 输送带特征点处张力 N FT1 输送带与滚筒相遇点的张力 N FT2 输送带与滚筒分离点的张力 N FTm 输送带的平均张力 N FTr 滚筒圆周驱动力 N FU 运行阻力(等于滚筒圆周驱动力) N FV 作用在滚筒上输送带的张力和滚筒旋转部分重力的矢量和(数值) N Fw 凸、凹弧曲线段的附加弯曲阻力 N Ft 前倾阻力 N ΔFTm 输送带的平均张力FTm与最小输送带张力FTmin之差 N Im,N 设计质量输送量 kg/s Im,th 理论质量输送量 kg/s IV,N 设计体积输送量 m3/s IV,th 理论体积输送量 m3/s J 滚筒的转动惯量 kg·m2 JD 驱动单元的转动部件在减速器高速轴上的转动惯量 kg·m2 Jf 飞轮的转动惯量 kg·m2 L 输送机的长度 m Ka 刮板系数 N/m PA 稳定运行条件下克服运行阻力所需的传动滚筒的总功率 kW PM 驱动电动机总功率 kW PM,N 驱动电动机额定功率 kW Q 设计输送量 t/h Ra 竖向凹弧段的曲率半径 m(mm)a Re 竖向凸弧段的曲率半径 m(mm)a S 相对于输送带名义拉断强度的安全系数 — S0 考虑接头工艺条件下的输送带的安全系数 — S1 考虑输送带预期寿命和工作应力的安全系数 — Smin 相对于输送带最小名义拉断强度的最小安全系数 — a 加速度或减速度 m/s2 b 输送带有效宽度(理论承载物料的输送带宽度) m(mm)a b1 物料堆积在输送带上的宽度 mm b2 3辊托辊组上的物料宽度 mm bS 位于侧辊上的输送带宽度(仅对于2辊和3辊托辊组) mm bSch 导料槽间的净宽 m c0 确定最小滚筒直径的计算系数 — cK 基于输送带边缘张力确定的最小接头疲劳强度的系数 — cR 将托辊转动质量等效到托辊周边上等效质量的计算系数 — cRank 主动侧压力系数 — cS 模拟摩擦系数的速度修正系数 — CSchb 加料段内由于物料扰动引起的附加阻力的系数 — cT 模拟摩擦系数的温度修正系数 — cTd 确定槽形过渡最小长度基准值的系数 — cε 前倾阻力的计算系数 — d0 滚筒轴承的内径 mm dB 输送带抗拉元件(芯层)的厚度(不包括输送带的上、下覆盖层的厚度) mm dR 托辊直径 m e 自然对数的底(e=2.718 28……) — eK 由输送带中性基准线到输送带边缘的高差 mm eM 由输送带中性基准线到输送带中心的高差 mm fbase 模拟摩擦系数的基准值 — Δfs 与带速相关的模拟摩擦系数的修正量 — ΔfT 与温度相关的模拟摩擦系数的修正量 — f 模拟摩擦系数 — fi 用以计算上、下分支各区段的模拟摩擦系数 — fr 在一定带速下托辊组辊子转动的频率 Hz fp 输送带的横截面振动的近似固有频率 Hz fRMBT 滚筒载荷系数(由输送带最大张力和名义拉断强度确定) — g 重力加速度(g=9.81 m/s2) m/s2 h 高差(上运时h>0；下运时h<0) m hk0 输送带两侧边缘构成的平面到槽形最低平面的距离 m hk1 输送带两侧边缘构成的平面与滚筒上母线所在平面的距离 m hTr 槽形过渡段滚筒上母线平面与槽形最低平面的距离(滚筒抬高高度) m i 传动比 — k 相对于输送带宽度的输送带张力(输送带张力在带宽上的平均值) N/ram kK 输送带边缘处单位宽度的张力 N/mm kM 输送带中心区域的单位宽度的张力 N/mm kN 输送带名义拉断强度 N/mm kN,min 输送带最小名义拉断强度 N/mm hrel 输送带的垂度(托辊组间输送带最大下垂量与托辊组间距之比) — kt 输送带接头基准疲劳强度(考虑输送带接头的强度降低的输送带拉断强度) N/mm kt,rel 输送带接头相对基准疲劳强度 — Δk 输送带边缘和输送带中心区域单位带宽上的张力的差值 N/mm l 区段的长度 m l2 中间2辊长度(5辊托辊组) mm lb 加料段导料槽的长度 m lK1 加料段外导料槽的长度 m lK 槽形过渡段输送带边缘的长度 m lM 3辊托辊组的中间辊的长度 mm(m)a lR 托辊组间距 m ls1 外侧托辊与物料的接触长度 m lTd 槽形过渡段的长度 m lTd,eff 钢丝绳芯输送带槽形过渡段的有效长度 m ΔlTd 过渡段的附加长度，钢丝绳芯输送带的lTd,eff-lTd m lw 输送带翻转段的长度 m mf 飞轮等效到滚筒周边的等效质量 kg mD 滚筒、飞轮(如果设置)、驱动和制动装置等效到滚筒周边的等效质量 kg mL 带式输送机线路上的输送带、物料和托辊的等效质量 kg ∑m 带式输送机线路上的输送带、物料和托辊的等效质量与滚筒、驱动和制动装置等效到滚筒周边的等效质量之和 kg n 带式输送机划分的区段数 — nR 带式输送机在稳定运行条件下允许的辊子最大转速 r/min pA 与传动滚筒相关的启动系数 N/mm pA,0 与驱动相关的起动系数 N/mm pB 与制动滚筒相关的制动系数 N/mm pB,0 与制动相关的制动系数 N/mm pD 功率分配系数 N/mm pGr 工作面清扫器作用到输送带上的压力 N/mm2 pGr1 非工作面清扫器作用到输送带上的压力 N/mm2 pSk 输送带与密封之间的有效单位长度正压力 N/m pBp 输送带的许用比压 N/mm2 pBs 钢丝绳芯输送带钢丝绳下的许用比压 N/mm2 q 主要阻力的估计系数 — qB 输送带的单位长度质量 kg/m qR 托辊旋转部分的单位长度质量 kg/m qG,i 区段上物料的单位长度质量 kg/m s1 输送带厚度 mm sSp 拉紧滚筒行程 m v 带速 m/s v0 给料到输送带上物料在输送方向的速度 m/s sB 制动距离 m t1 输送带的钢丝绳间距 mm tB 制动时间 s zD 传动或制动滚筒的数量 个 zM 电动机(驱动单元)的数量 个 zR 区段上(上或下分支)托辊组的数量 组 zTr 滚筒的数量 个 zt 区段上(上或下分支)前倾托辊组的数量 组 α 围包角 °或rad αc 凸、凹弧曲线段对应的圆心角 rad β 用于与物料计算物料横截面积的物料动堆积角的等效堆积角 — θ 输送物料的动堆积角(安息角) — δ 输送倾角(上运时δ>0，下运时δ<0) — ε 侧辊倾斜角(前倾角) — φ 有效填充系数 — φSt 倾斜输送时理论总承载截面积的截面缩减系数 — φSt1 倾斜输送时承载物料的上部的理论截面积的截面缩减系数 — λ 托辊组槽角、外侧辊的槽角(4、5辊托辊组) — λ1 中间2辊的槽角(4、5辊托辊组) — μ 输送带与滚筒间的摩擦系数 — μ1 输送带与输送物料间的摩擦系数 — μ2 输送物料与导料槽侧板间的摩擦系数 — μ3 输送带与托辊间的摩擦系数 — μ4 输送带与清扫器间的摩擦系数 — μ5 输送带与密封橡胶间的滑动摩擦系数 — μ6 缓冲床与输送带间的摩擦系数 — ρ 输送物料的堆积密度 kg/m3 ΔεK 相对于输送带自然轴向凹弧段或凸弧段上输送带边缘的附加伸长率(正或负) — ΔεK∞ 很长的曲线段输送带边缘的ΔεK的极限值 — ΔεM 相对于输送带自然轴向凹弧段或凸弧段上输送带中心区域的附加伸长率(正或负) — ΔεM∞ 很长的曲线段输送带中心区域的ΔεM的极限值 — Δε∞ 很长的曲线段输送带中心区域与输送带边缘之间的伸长率的差 — η1 电动工况电动机轴与滚筒轴之间全部传动环节的总效率 — η2 发电工况电动机轴与滚筒轴之间全部传动环节的总效率 — a 有些计算式中采用括弧内的单位。 5体积输送量和质量输送量 5.1 物料理论横截面积 带式输送机的理论体积输送量和质量输送量是由所输送物料在输送带上堆积形成的物料理论横截面积和运行速度所决定的。物料的横截面积则取决于输送物料的动堆积角、托辊组的具体结构型式及装料方式。 本标准在计算理论体积输送量和质量输送量时，假设所输送物料横截面的上表面的轮廓线为抛物线。图1为常见槽形3辊托辊组支承输送带上的物料横截面。 图1 3辊托辊组水平输送承载物料的理论横截面 承载物料的理论横截面积由承载托辊组的中间辊子长度lM、槽角λ、输送带有效宽度b及动堆积角θ确定。有效宽度b是在输送带宽度上留有一定的空边距以避免输送带撒料的宽度，见式(1)、式(2)： b=0.9B-50(当B≤2 000) (1) b=B-250(当B>2 000) (2) 式中： B——带宽，单位为毫米(mm)； b——输送带有效宽度(理论承载物料的输送带宽度)，单位为毫米(mm)。 水平转弯运行的带式输送机由于辊子的倾斜布置可能会减小输送带的有效宽度。 水平布置的带式输送机的3辊托辊组支承输送带承载物料采用动堆积角θ计算的理论截面积Ath，可用截面积A1,th与A2,th之和来确定(见图1)，见式(3)、式(4)、式(5)： (3) (4) Ath=A1,th+A2,th (5) 式中： Ath——承载物料的理论横截面积，单位为平方米(m2)； A1,th——承载物料的上部的理论横截面积，单位为平方米(m2)； A2,th——当θ=0°时的承载物料理论横截面积(承载物料的下部的截面积)，单位为平方米(m2)； lM——3辊托辊组的中间辊的长度，单位为米(m)； θ——物料的动堆积角，单位为度(°)； λ——托辊组槽角，单位为度(°)； b——输送带有效宽度(理论承载物料的输送带宽度)，单位为米(m)。 当采用等效堆积角β计算横截面积A1,th时，见式(6)： (6) 其中，β=θ/1.5。 物料的动堆积角取决于所输送的物料的特性和带式输送机的长度、带速等因素。在缺乏动堆积角经验值情况下，可选择： ——对于正常流动性物料，取0≤θ≤20°； ——对于流动性较高的物料，则取20°≤θ≤30°。 2辊托辊组承载物料的理论截面积：将lM=0代入式(3)和式(4)进行计算； 1辊托辊组承载物料的理论截面积：将lM=0，λ=0代入式(3)和式(4)进行计算。 1辊、2辊、4辊、5辊托辊组承载物料的理论横截面积Ath的计算参见附录A。 根据承载物料的理论横截面积，理论体积输送量，见式(7)： IV,th=Ath·v (7) 理论质量输送量，见式(8)： Im,th=ρAth·v (8) 式中： IV,th——理论体积输送量，单位为立方米每秒(m3/s)； Im,th——理论质量输送量，单位为千克每秒(kg/s)； v——带速，单位为米每秒(m/s)； ρ——输送物料的堆积密度，单位为千克每立方米(kg/m3)。 5.2倾斜输送的横截面缩减系数 当带式输送机给料均匀、且水平、直线运行时，带式输送机的理论物料截面可以充分利用。 倾斜输送时，受到物料重力、内摩擦角等因素的影响，图1中的上部面积A1,th将缩减。当带式输送机对中良好并均匀给料、输送粒度小的物料；且带式输送机线路上的最大倾角δmax≤θ时，上部面积的缩减系数，见式(9)： (9) 式中： φSt1——倾斜输送时承载物料的上部的理论截面积A1,th的截面缩减系数，无量纲； δmax——带式输送机线路上的最大倾角，单位为度(°)； θ——同式(3)。 倾斜输送的承载物料的理论截面积缩减系数φSt，见式(10)： (10) 式中： φSt——倾斜输送时承载物料的理论截面积Ath的截面缩减系数，无量纲。 在应用式(9)、式(10)时，应注意倾斜输送时的倾角最大只能等于动堆积角θ。此时只有截面积A2,th用于输送物料。 5.3 设计输送量和有效填充系数 当给定物料的设计质量输送量Im,N时，设计体积输送量IV,N，见式(11)： (11) 式中： Im,N——设计质量输送量，单位为千克每秒(kg/s)； IV,N——设计体积输送量，单位为立方米每秒(m3/s)。 所需要的截面积，见式(12)： (12) 式中： AN——在设计输送量下需要的承载物料横截面积，单位为平方米(m2)。 带式输送机的有效填充系数，见式(13)： (13) 式中： φ——带式输送机的有效填充系数，无量纲。 有效填充系数φ取决于： ——输送物料的特性； ——粒度及其组成； ——动堆积角θ； ——带式输送机的运行条件； ——给料均匀性； ——输送机的线路布置； ——输送倾角； ——输送能力的储备。 有效填充系数φ用以评价理论物料截面积Ath与设计输送量下所需截面积匹配性。在本标准中，一些计算参数是在有效填充系数为0.7<φ<1.1范围内进行选择，否则，应对所选计算参数进行修正，并且在某些情况下将超出上述的范围，具体数值将依据试验数据和工程师的经验。 设计输送量下的物料单位长度质量，见式(14)： 或qG=φρAth (14) 式中： qG——设计输送量下输送带上物料的单位长度质量，单位为千克每米(kg/m)。 设计输送量计算见式(15)： (15) 式中： Q——设计输送量，单位为吨每小时(t/h)。 6 稳定运行条件的运行阻力和功率消耗 6.1 计算原则 运行阻力的计算通常是首先估计所用参数(如输送带和托辊的单位长度质量、模拟摩擦系数等)数值的基准值。这些数值应在计算过程中根据实际选择确认或修正。通常应进行反复计算，以达到完全符合具体应用的计算结果。 在稳定运行条件时产生的运行阻力FU是由摩擦力、重力和其他阻力产生的总阻力。带式输送机传动滚筒所需要的功率PA是由上、下分支产生的运行阻力总和与运行速度v的乘积得出，见式(16)： (16) 式中： PA——稳定运行条件抵抗运行阻力所需的传动滚筒圆周上的总功率，单位为千瓦(kW)； FU——上、下分支运行阻力的总和，单位为牛顿(N)。 为了计算运行阻力，将带式输送机运行阻力划分为： ——主要阻力FH(见6.2)； ——附加阻力FN(见6.3)； ——提升阻力FSt(见6.4)； ——特种阻力FS(见6.5)。 运行阻力之和FU等于从传动滚筒传递到输送带上的滚筒圆周驱动力FTr，见式(17)： (17) 式中： FTr——滚筒圆周驱动力的总和，单位为牛顿(N)； FU,o,i、FU,u,i——分别为上、下分支、区段i上运行阻力，单位为牛顿(N)； no、nu——分别为上、下分支划分的区段数。 阻力应以分段形式确定。分段的原则是在每个区段上具有相同的计算参数，例如：带式输送机的上分支、下分支，区段上的倾角δi、模拟摩擦系数，fi和单位长度物料的质量qG,i，以及托辊旋转部分的单位长度质量qR,i。考虑到方便计算机编程计算，在阻力计算中，可以采用从带式输送机的尾部到头部进行编号，脚标i为区段的序号，脚标o表示上分支、u表示下分支(见图2)，将滚筒作为单独的区段编号。在后面的描述中，为了表达统一，将滚筒编号用脚标j表示，脚标T1为相遇点、T2为分离点。(见图5和图6)。 6.2主要阻力 6.2.1 主要阻力的计算 主要阻力发生在所有的带式输送机的输送线路的整个长度上。它包括：托辊旋转阻力、输送带压陷滚动阻力、输送带弯曲阻力和物料内摩擦阻力等。主要阻力应在各个区段上分别计算。 为了简化区段阻力的计算，按照阻力与运动载荷为线性关系来分别计算上、下分支每个区段主要阻力FH,i，见式(18)： FH,i=lifig[qR,i+(qB+qG,i)cosδi] (18) 式中： FH,i——区段i上的主要阻力，单位为牛顿(N)； li——区段i的长度，单位为米(m)； fi——区段i上的模拟摩擦系数，无量纲； qR,i——区段i上托辊旋转部分的单位长度质量，单位为千克每米(kg/m)； qB——输送带的单位长度质量，单位为千克每米(kg/m)； qG,i——区段i上物料的单位长度质量，单位为千克每米(kg/m)； δi——区段i的输送倾角，单位为度(°)； g——重力加速度，单位为米每二次方秒(m/s2)。 在确定输送带张力时，必需确定上、下分支区段主要阻力FH,o,i、FH,u,i(见8.3)。 带式输送机的主要阻力是上、下分支主要阻力FH,o、FH,u之和，见式(19)： (19) 式中： FH——总的上、下分支主要阻力，单位为牛顿(N)； FH,o,i、FH,u,i——分别为上、下分支区段i上主要阻力，单位为牛顿(N)； FH,o、FH,u——分别为上、下分支主要阻力的和，单位为牛顿(N)。 头部 上分支运行方向 尾部 说明： 0、1、2——输送机线路特征点； lo,1、lo,2、lu,1、lu2——分别为上分支、下分支区段1，2的长度； FU,o,1、FU,o,2、FU,o,2、FU,o,2——分别为上分支、下分支区段1，2上运行阻力。 图2 区段划分和稳定工况下的各段运行阻力 计算各区段主要阻力时，物料的有效填充系数应在0.7<φ<1.1的范围内。否则，应对本标准所给出的计算参数的基准值进行修正。 在带式输送机线路中含有上运和下运区段时，应在极端载荷条件(给料不均匀、部分载荷和空载)下计算主要阻力，因为在这种情况下的阻力之和可能大大超过稳定运行条件下的阻力。 6.2.2模拟摩擦系数的确定 选择模拟摩擦系数fi比主要阻力的计算更为重要，因为它决定了主要阻力。特别是对于提升阻力较小的带式输送机尤为重要。表2中给出的模拟摩擦系数厂i值可以用作上、下分支主要阻力计算。 如没有测量值或经验值，或仅有粗略的设备参数，可根据表2中运行条件和结构特性选取模拟摩擦系数厂的基准值。这些基准值是通过对上、下分支大量的测量及下列限制条件总结得出的： ——上分支为3辊固定式托辊组； ——辊子采用滚动轴承和迷宫式密封； ——输送带垂度hrc1≤0.01； ——有效填充系数为0.7<φ<1.1。 在实际设计中，为保证有较高的安全性，对于驱动装置为发电运转方式，采用较小的模拟摩擦系数f；对于驱动装置为电动运转方式，采用较大的模拟摩擦系数f。 如果计算精确度要求不高，可以采用此模拟摩擦系数f，按式(18)计算主要阻力。 表2模拟摩擦系数f的基准值(有效填充系数为0.7<φ<1.1) 特征 特征程度 输送物料的内摩擦 中等 低 高 带式输送机的对中性 中等 好 差 输送带张力 中等 高 低 运行条件(粉尘，黏性) 中等 好 差 托辊直径/mm 108～159 >159 <108 上分支托辊组间距/m 1.0～1.5 <1.0 >1.5 下分支托辊组间距/m 2.5～3.5 <2.5 >3.5 带速/(m/s) 4～6 <4 >6 槽角/(°) 25～35 <25 >35 环境温度/℃ 15～25 >25 <15 模拟摩擦系数f 基准值≈0.020 导致 模拟摩擦系数f减小至 模拟摩擦系数f增大至 0.010 0.040 6.2.3考虑温度和带速的模拟摩擦系数的修正方法 当考虑温度和带速的影响对模拟摩擦系数进行修正时，首先用表3确定模拟摩擦系数fbase的基准值。 不同带建下的模拟摩擦系数的修正量，见式(20)： ΔfS=0.02·(cS-1) (20) 式中： ΔfS——与带速相关的模拟摩擦系数的修正量，无量纲； cS——由表4给出的模拟摩擦系数的速度修正系数，无量纲。 不同工作温度下的模拟摩擦系数的修正量，见式(21)： ΔfT=0.02·(cT-1) (21) 式中： ΔfT——与温度相关的模拟摩擦系数的修正量，元量纲； cT——由表5给出的模拟摩擦系数的温度修正系数，无量纲。 表3模拟摩擦系数fbase的基准值 安装情况 工作条件 模拟摩擦系数fbase 水平、向上输送及向下输送的电动工况，带速5 m/s 良好的工作条件，托辊转动灵活，输送物料的内摩擦较小，良好的安装与维护 0.017 正常的安装，通常的物料 0.02 不好的工作条件，低温，物料的内摩擦高，物料超载，维护差 0.023～0.030 下运发电工况，带速5 m/s 制造、安装正常，电动机为发电运行条件 0.012～0.016 表4速度修正系数cS 带速v/(m/s) 2 3 4 5 6 系数cS 0.80 0.85 0.90 1.00 1.10 表5温度修正系数cT 温度/℃ +20 0 -10 -20 -30 系数cT 1.00 1.07 1.17 1.28 1.47 修正的模拟摩擦系数，见式(22)： f=fbase+ΔfS+ΔfT (22) 式中： fbase——模拟摩擦系数的基准值，无量纲。 应用式(21)修正的模拟摩擦系数是偏于保守的。精确的模拟摩擦系数取决于实际所采用的输送带的类型和输送机的结构设计。当带速或温度不是表4或表5中的数值时，可以通过插值法计算修正量。 6.2.4通过托辊转动阻力和压陷滚动阻力测量确定主要阻力的方法 为了在保证带式输送机性能的同时最小化设备和运营成本，应精确确定模拟摩擦系数f值。模拟摩擦系数fi主要是由托辊转动阻力和输送带的压陷滚动阻力确定。当输送带垂度相对较大时，输送物料的挤压阻力也会占较大比例。当测得托辊转动阻力和压陷滚动阻力时，可用下面的方法估算主要阻力。 在有效填充系数为0.7≤φ≤1.1情况下，承载区段(一般情况下是上分支区段)输送带的压陷滚动阻力和托辊转动阻力之和的正常值在主要阻力中占50％～85％，平均值为70％。空载区段(一般情况下是下分支区段)约为主要阻力的90％。