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存檔編碼： 無(wú)錫太湖學(xué)院 2013 屆畢業(yè)作業(yè)周次進(jìn)度計(jì)劃、檢查落實(shí)表 系別：信機(jī)系 班級(jí)：機(jī)械95 學(xué)生姓名：李歡 課題（設(shè)計(jì)）名稱：工業(yè)窯爐的設(shè)計(jì)（輸送裝置） 開(kāi)始日期：2012年11月12日 周 次 起止日期 工作計(jì)劃、進(jìn)度 每周主要完成內(nèi)容 存在問(wèn)題、改進(jìn)方法 指導(dǎo)教師意見(jiàn)并簽字 備 注 1-3 2012年11月12日-2012年12月2日教師下達(dá)畢業(yè)設(shè)計(jì)任務(wù)，學(xué)生初步閱讀資料，完成畢業(yè)設(shè)計(jì)開(kāi)題報(bào)告。 按照任務(wù)書(shū)要求查閱論文相關(guān)參考資料，填寫畢業(yè)設(shè)計(jì)開(kāi)題報(bào)告書(shū) 存在問(wèn)題：對(duì)課題理解模糊，對(duì)設(shè)計(jì)目的及要求不明確，實(shí) 際設(shè)計(jì)能力不足。 改進(jìn)方法：向指導(dǎo)老師請(qǐng)教，通過(guò)導(dǎo)師指導(dǎo)后，翻閱圖書(shū)館 的書(shū)籍等途徑查閱資料，重新填寫報(bào)告。 4-10 2012年12月3日-2013年1月20日 指導(dǎo)專業(yè)實(shí)訓(xùn) 機(jī)械制造綜合實(shí)訓(xùn)，機(jī)械零件加工方法和加工工藝編制 存在問(wèn)題：發(fā)現(xiàn)理論知識(shí)與實(shí)際操作、設(shè)計(jì)存在很大差別， 加工工藝編制存在著一些問(wèn)題。 改進(jìn)方法：及時(shí)的對(duì)自己的知識(shí)點(diǎn)查漏補(bǔ)缺，了解設(shè)備的基 本操作及特點(diǎn)，理解工藝編制，重新修訂加工工藝。 11-12 2013年1月21日-3月1日 指導(dǎo)畢業(yè)實(shí)習(xí) 到企業(yè)進(jìn)行崗位實(shí)習(xí)，了解本專業(yè)的實(shí)踐知識(shí) 存在問(wèn)題：缺乏實(shí)際動(dòng)手能力。操作中遇到問(wèn)題無(wú)法自己解 決。 改進(jìn)方法：向工廠師傅請(qǐng)教，不斷學(xué)習(xí)，恪盡職守的工作。 補(bǔ)充自己專業(yè)知識(shí)和師傅們討論一起解決一些難題。 13 2013年3月4日-3月8日 查閱參考資料 查閱與設(shè)計(jì)有關(guān)的參考資料不少于10篇，其中外文不少于5篇 存在問(wèn)題：身邊資料欠缺，相關(guān)理論知識(shí)不足。 改進(jìn)方法：利用空余的時(shí)間去校圖書(shū)館、新華書(shū)店等地方翻 閱書(shū)籍、在相關(guān)專業(yè)網(wǎng)上搜索相關(guān)資料，并利用工作之余在 網(wǎng)上搜索相關(guān)資料加以整理修改。 14 2013年3月11日-3月15日 翻譯外文資料 翻譯外文資料（8000-10000字符） 存在問(wèn)題：英語(yǔ)水平低，專業(yè)詞匯不足。 改進(jìn)方法：上網(wǎng)查詢，翻閱字典并結(jié)合翻閱軟件，向同學(xué)求 助等方法，不斷提升英語(yǔ)翻譯能力。 15 2013年3月18日-3月22日 熟悉帶式輸送機(jī)的整體裝配 分析產(chǎn)品圖、分析零件，優(yōu)選確定零件的制造方案 存在問(wèn)題：缺乏設(shè)計(jì)經(jīng)驗(yàn)，零件制造方案不合理，存在材料 浪費(fèi)，工藝性差。 改進(jìn)方法：多去車間部門了解實(shí)際生產(chǎn)過(guò)程，向有相關(guān)設(shè)計(jì) 的工程師和同學(xué)尋求幫助，設(shè)計(jì)合理的結(jié)構(gòu)方案，建立正確 的零件制造方案。 16 2013年3月25日-3月29日 選用適宜電動(dòng)機(jī) 確定零件尺寸 存在問(wèn)題：零件尺寸設(shè)計(jì)不合理。 改進(jìn)方法：詢問(wèn)導(dǎo)師及工廠師傅，上網(wǎng)查找電動(dòng)機(jī)相關(guān)參數(shù) 。 17 2013年4月1日-4月5日 減速器齒輪和軸系零件的選用 初步確定零件尺寸 存在問(wèn)題：計(jì)算原理不對(duì)，錯(cuò)誤使用各種計(jì)算公式，沒(méi)有合 理的排布尺寸。 改進(jìn)方法：查閱相關(guān)資料，翻閱理解前人的設(shè)計(jì)方案和書(shū)籍 ，通過(guò)分析公式的計(jì)算原則和應(yīng)用條件，合理運(yùn)用各種公式 計(jì)算出所需尺寸。 18 2013年4月8日-4月12日 主要零件結(jié)構(gòu)設(shè)計(jì)和計(jì)算 主要零件結(jié)構(gòu)設(shè)計(jì)和尺寸計(jì)算 存在問(wèn)題：箱體零件的結(jié)構(gòu)設(shè)計(jì)不合理，甚至存在不能按設(shè) 計(jì)要求加工的情況，零件結(jié)構(gòu)尺寸選取不合理。選用零件不 合理。 改進(jìn)方法：詢問(wèn)指導(dǎo)老師，結(jié)合加工設(shè)備，重新零件及結(jié)構(gòu) 。 周 次 起止日期 工作計(jì)劃、進(jìn)度 每周主要完成內(nèi)容 存在問(wèn)題、改進(jìn)方法 指導(dǎo)教師意見(jiàn)并簽字 備 注 19 2013年4月15日-4月19日 畫(huà)零件圖，裝配圖及爆炸圖 初步繪制沖壓模裝配圖 存在問(wèn)題：不能熟練操作繪圖軟件的指令，實(shí)際裝配不正確 。 改進(jìn)方法：加以訓(xùn)練CAD、UG等繪圖軟件，并表示出合理的 裝配關(guān)系。 20 2013年4月22日-4月26日 完成裝配圖 初步完成裝配圖紙 存在問(wèn)題：裝配圖中標(biāo)準(zhǔn)件畫(huà)法及查找的尺寸不正確，填寫 技術(shù)要求意識(shí)模糊，沒(méi)能正確填寫明細(xì)欄和技術(shù)要求。標(biāo)注 不合理。 改進(jìn)方法：翻閱書(shū)本，請(qǐng)導(dǎo)師檢閱。改正正確畫(huà)法及尺寸 21 2013年4月29日-5月10日 繪制零件圖 繪制減速器主要零件的零件圖 存在問(wèn)題：零件圖的表達(dá)方案不合理，零件圖上尺寸公差不 合理，粗糙度選用不規(guī)范。對(duì)于一些重要零件沒(méi)能正確表示 。 改進(jìn)方法：請(qǐng)老師檢閱修改零件圖以求以求達(dá)到合理要求。 22 2013年5月13日-5月17日 設(shè)計(jì)說(shuō)明書(shū)（論文）、摘要和小結(jié)編寫 完成設(shè)計(jì)說(shuō)明書(shū)（論文）、摘要和小結(jié) 存在問(wèn)題：說(shuō)明書(shū)（論文）的格式不規(guī)范，摘要不合理要求 等。 改進(jìn)方法：按學(xué)院要求重新修改書(shū)面格式，重新并編寫摘要 。 23 2013年5月20日-5月25日 上交資料、準(zhǔn)備答辯 整理所有資料，打印后上交指導(dǎo)教師，準(zhǔn)備答辯 按指導(dǎo)老師要求結(jié)合學(xué)院要求整理書(shū)籍及資料 說(shuō)明： 1、“工作計(jì)劃、進(jìn)度”、“指導(dǎo)教師意見(jiàn)并簽字”由指導(dǎo)教師填寫，“每周主要完成內(nèi)容”，“存在問(wèn)題、改進(jìn)方法”由學(xué)生填寫。 2、本表由各系妥善歸檔，保存?zhèn)洳椤?編號(hào)
無(wú)錫太湖學(xué)院
畢業(yè)設(shè)計(jì)（論文）
相關(guān)資料
題目： 工業(yè)窯爐的設(shè)計(jì)（輸送裝置）
信機(jī) 系 機(jī)械工程及自動(dòng)化 專業(yè)
學(xué) 號(hào)： 0923220
學(xué)生姓名： 李 歡
指導(dǎo)教師： 徐偉明（職稱： 教 授 ）
（職稱： ）
2013年5月25日
目 錄
一、畢業(yè)設(shè)計(jì)（論文）開(kāi)題報(bào)告
二、畢業(yè)設(shè)計(jì)（論文）外文資料翻譯及原文
三、學(xué)生“畢業(yè)論文（論文）計(jì)劃、進(jìn)度、檢查及落實(shí)表”
四、實(shí)習(xí)鑒定表
無(wú)錫太湖學(xué)院
畢業(yè)設(shè)計(jì)（論文）
開(kāi)題報(bào)告
題目： 工業(yè)窯爐的設(shè)計(jì)（輸送裝置）
信機(jī)系 機(jī)械工程及自動(dòng)化 專業(yè)
學(xué) 號(hào)： 0923220
學(xué)生姓名： 李 歡
指導(dǎo)教師： 徐偉明（職稱： 教 授 ）
（職稱： ）
2012年11月20日
課題來(lái)源
本課題來(lái)源于導(dǎo)師布置的任務(wù)導(dǎo)老師
科學(xué)依據(jù)（包括課題的科學(xué)意義；國(guó)內(nèi)外研究概況、水平和發(fā)展趨勢(shì)；應(yīng)用前景等）
輸送裝置的設(shè)計(jì)是機(jī)械工程及其自動(dòng)化專業(yè)所包含的一個(gè)較為基礎(chǔ)的內(nèi)容，選擇輸送裝置方向的畢業(yè)設(shè)計(jì)題目完全符合本專業(yè)的要求，從應(yīng)用性方面來(lái)說(shuō)，輸送裝置又是很多機(jī)器所必不可少的一個(gè)部分。有效保證輸送裝置的功率及穩(wěn)定性能夠達(dá)到設(shè)計(jì)的要求，具有很好的發(fā)展前途和應(yīng)用前景。
研究?jī)?nèi)容
1、 選擇電動(dòng)機(jī)，計(jì)算傳動(dòng)裝置的運(yùn)動(dòng)和動(dòng)力參數(shù)；
2、 擬定、分析傳動(dòng)裝置的運(yùn)動(dòng)和動(dòng)力參數(shù)；
3、 進(jìn)行傳動(dòng)件的設(shè)計(jì)計(jì)算，校核軸、軸承、聯(lián)軸器、鍵等；
4、 繪制減速器裝配圖及典型零件圖（圖紙數(shù)達(dá)到3張或以上）；
5、 完成設(shè)計(jì)說(shuō)明一份，分析明晰，計(jì)算正確，闡述清楚。適合的生產(chǎn)加工工 藝
擬采取的研究方法、技術(shù)路線、實(shí)驗(yàn)方案及可行性分析
首先確定整體設(shè)計(jì)方案，由公式的演算得到電動(dòng)機(jī)的動(dòng)力和運(yùn)動(dòng)分析，在以此推算相配的傳動(dòng)件，軸系零部件的尺寸規(guī)格。綜上計(jì)算可以得到相關(guān)尺寸，再根據(jù)力學(xué)性能對(duì)所得零部件尺寸進(jìn)行校驗(yàn)從而驗(yàn)證整體方案是否可行。
研究計(jì)劃及預(yù)期成果
研究計(jì)劃：
2012年11月 布置任務(wù)。
2013年1月 對(duì)課題研究方向進(jìn)行學(xué)習(xí)
2013年2月~3月 擬定方案，提出專機(jī)總體方案，供討論
2013年4月5日~10日 確定方案，專機(jī)總體布置
11日~20日 整機(jī)設(shè)計(jì)、部件設(shè)計(jì)
21日~30日 改進(jìn)并完成設(shè)計(jì)
2013年5月1日~10日 撰寫設(shè)計(jì)說(shuō)明書(shū)
11日~15日 總結(jié)
預(yù)期成果：圖紙、設(shè)計(jì)說(shuō)明書(shū)
特色或創(chuàng)新之處
帶式輸送機(jī)本身便具有價(jià)格便宜，標(biāo)準(zhǔn)化程度高特點(diǎn)，使成本大幅降低。高速級(jí)齒輪常布置在遠(yuǎn)離扭矩輸入端的一邊，以減小因彎曲變形所引起的載荷沿齒寬分布不均現(xiàn)象。
已具備的條件和尚需解決的問(wèn)題
與指導(dǎo)老師的溝通中，對(duì)自己所做課題有了整體的認(rèn)識(shí)，清晰了思路。指導(dǎo)老師提供了論文指導(dǎo)，從而使自己明確了每一步的方向。因第一次繪制復(fù)雜的裝配圖，所以在繪圖方面還有待提高。
指導(dǎo)教師意見(jiàn)
同意作為本專業(yè)學(xué)生畢業(yè)設(shè)計(jì)課題，其難度和工作量均合適。
指導(dǎo)教師簽名：
年 月 日
教研室（學(xué)科組、研究所）意見(jiàn)
教研室主任簽名：
年 月 日
系意見(jiàn)
主管領(lǐng)導(dǎo)簽名：
年 月 日
英文原文
Esign of Speed Belt Conveyors
G. Lodewijks, The Netherlands.
This paper discusses aspects of high-speed belt conveyor design. The capacity of a belt conveyor is determined by the belt speed given a belt width and troughing angle. Belt speed selection however is limited by practical considerations, which are discussed in this paper. The belt speed also affects the performance of the conveyor belt, as for example its energy consumption and the stability of it's running behavior. A method is discussed to evaluate the energy consumption of conveyor belts by using the loss factor of transport. With variation of the belt speed the safety factor requirements vary, which will affect the required belt strength. A new method to account for the effect of the belt speed on the safety factor is presented. Finally, the impact of the belt speed on component selection and on the design of transfer stations is discussed.
Belt machine by conveyor belt continuous or intermittent motion to transport all kinds of different things ，Can transport all kinds of bulk materials, but also transport a variety of cardboard boxes, packaging bags, weight of single pieces of small goods, a wide range of uses . Belt conveyor belt material: rubber, silicone, PVC, PU and other materials, in addition to ordinary material conveying, but also to meet the transmission oil resistant, corrosion resistance, antistatic and other special requirements for material. Belt conveyor structure: groove belt machine, flat belt conveyor, climbing belt machine, turning machines and other forms belt, conveyor belt can also be created to enhance the tailgate, skirts and other accessories, can meet a variety of technological requirements.The belt conveyor drive: deceleration motor drive, electric drive roller.Belt conveyor mode: frequency control, stepless transmission.The belt rack material: carbon steel, stainless steel, aluminum profile.Scope of application: light industry, electronics, food, chemical, wood, etc..Belt machine equipment characteristics: belt conveyor is stable, the material and the conveyor belt there is no relative motion, to avoid damage to the carrier material. Low noise, suitable for quiet work environment requirements. Simple structure, easy maintenance. Low energy consumption, low use cost.
Conveyor is a common don't have flexible traction component continuous conveying machinery, also called continuous conveyor.It is a material handling equipment, it with handling ability strong, persistent, direction, flexible, and other advantages in industrial production in large being applied. Although many types of belt conveyor, but its working principle is basic similar, most are driving draught device and drive transmission container transport materials. Conveyor can undertake level, the tilt and vertical conveyor, also can make the space transport routes, transmission lines is usually fixed, is a modern production and logistics transport indispensable important mechanical equipment. It has transmission capacity is strong, long distance transportation etc.
With the development of industry, conveyor also obtained fast development, conveyor products have been also gradually improved. With the emergence of the power equipment of similar principle is applied, conveyor continuing into the 19th century, britons use basketwork, wire rope for traction belt conveyor. The principle of belt conveyor, when applied in the 17th century also recorded conveyor, in 1880 German company developed driven by steam belt conveyor. Then the British and German and launched inertial conveyor, if the conveyor belt, the application of the principle, creating a tilt of the belt conveyor, belt, traction with chains. All sorts of conveyor during this time arise conveyor, based on human, hydraulic power drive such. All the structures conveyor successively appeared. In 1887 americans produced the screw conveyor, make enterprise internal, between enterprise and inter-city transportation possible. The development history of belt conveyor, they very ancient instead of the original motive for conveyor provide driving force. Ancient people began to use water overturned and high TongChe conveyor, in turn after the water conservancy project's belt conveyor begin in power. Quick-tempered exalts
According to the mode of operation conveying machinery can be divided into: 1: belt conveyor 2: screw conveyor 3: dou pattern lift machine
The future of large scale, will toward belt use scope, energy consumption, low pollution less, material automatically grading, etc.
Past research has shown the economical feasibility of using narrower, faster running conveyor belts versus wider, slower running belts for long overland belt conveyor systems. See for example [I]-[5]. Today, conveyor belts running at speeds around 8 m/s are no exceptions. However, velocities over 10 m/s up to 20 m/s are technically (dynamically) feasible and may also be economically feasible. In this paper belt speeds between the 10 and 20 m/s are classified as high. Belt speeds below the 10 m/s are classified as low.
Using high belt speeds should never be a goal in itself. If using high belt speeds is not economically beneficial or if a safe and reliable operation is not ensured at a high belt speed then a lower belt speed should be selected.
Selection of the belt speed is part of the total design process. The optimum belt conveyor design is determined by static or steady state design methods. In these methods the belt is assumed to be a rigid, inelastic body. This enables quantification of the steady-state operation of the belt conveyor and determination of the size of conveyor components. The specification of the steady-state operation includes a quantification of the steady-state running belt tensions and power consumption for all material loading and relevant ambient conditions. It should be realized that finding the optimum design is not a one-time effort but an iterative process [6].
Design fine-tuning, determination of the optimum starting and stopping procedures, including determination of the required control algorithms, and determination of the settings and sizes of conveyor components such as drives, brakes and flywheels, are determined by dynamic design methods. In these design methods, also referred to as dynamic analyses, the belt is assumed to be a three-dimensional (visco-) elastic body. A three dimensional wave theory should be used to study time dependent transmission of large local force and displacement disturbances along the belt [7]. In this theory the belt is divided into a series of finite elements. The finite elements incorporate (visco-) elastic springs and masses. The constitutive characteristics of the finite elements must represent the rheological characteristics of the belt. Dynamic analysis produces the belt tension and power consumption during non-stationary operation, like starting and stopping, of the belt conveyor.
This paper discusses the design of high belt-speed conveyors, in particular the impact of using high belt speeds on the performance of the conveyor belt in terms of energy consumption and safety factor requirements. Using high belt speeds also requires high reliability of conveyor components such as idlers to achieve an acceptable component life. Another important aspect of high-speed belt conveyor design is the design of efficient feeding and discharge arrangements. These aspects will be discussed briefly.
Many methods of analyzing a belt’s physical behavior as a rheological spring have been studied and various techniques have been used. An appropriate model needs to address:
1. Elastic modulus of the belt longitudinal tensile member
2. Resistances to motion which are velocity dependent (i.e. idlers)
3. Viscoelastic losses due to rubber-idler indentation
4. Apparent belt modulus changes due to belt sag between idlers
Since the mathematics necessary to solve these dynamic problems are very complex, it is not the goal of this presentation to detail the theoretical basis of dynamic analysis. Rather, the purpose is to stress that as belt lengths increase and as horizontal curves and distributed power becomes more common, the importance of dynamic analysis taking belt elasticity into account is vital to properly develop control algorithms during both stopping and starting.
Using the 8.5 km conveyor in Figure 23 as an example, two simulations of starting were performed to compare control algorithms. With a 2x1000 kW drive installed at the head end, a 2x1000 kW drive at a midpoint carry side location and a 1x1000kW drive at the tail, extreme care must be taken to insure proper coordination of all drives is maintained.
Figure 27 illustrates a 90 second start with very poor coordination and severe oscillations in torque with corresponding oscillations in velocity and belt tensions. The T1/T2 slip ratio indicates drive slip could occur. Figure 28 shows the corresponding charts from a relatively good 180 second start coordinated to safely and
smoothly accelerate the conveyor.
Figure 27-120 Sec Poor Start
BELTSPEED
BELT SPEED SELECTION
The lowest overall belt conveyor cost occur in the range of belt widths of 0.6 to 1.0 m [2]. The required conveying capacity can be reached by selection of a belt width in this range and selecting whatever belt speed is required to achieve the required flow rate. Figure 1 shows an example of combinations of belt speed and belt width to achieve Specific conveyor capacities. In this example it is assumed that the bulk density is 850 kg/m3 (coal) and that the trough angle and the surcharge angle are 35' and 20' respectively.
Figure 1: Belt width versus belt speed for different capacities.
Belt speed selection is however limited by practical considerations. A first aspect is the troughability of the belt. In Figure 1 there is no relation with the required belt strength (rating), which partly depends on the conveyor length and elevation. The combination of belt width and strength must be chosen such that good troughability of the belt is ensured. If the troughability is not sufficient then the belt will not track properly. This will result in unstable running behavior of the belt, in particular at high belt speeds, which is not acceptable. Normally, belt manufacturers expect a sufficiently straight run if approximately 40% of the belt width when running empty, makes contact with the carrying idlers. Approximately 10% should make tangential contact with the center idler roll.
A second aspect is the speed of the air relative to the speed of the bulk solid material on the belt (relative airspeed). If the relative airspeed exceeds certain limits then dust will develop. This is in particular a potential problem in mine shafts where a downward airflow is maintained for ventilation purposes. The limit in relative airspeed depends on ambient conditions and bulk material characteristics.
A third aspect is the noise generated by the belt conveyor system. Noise levels generally increase with increasing belt speed. In residential areas noise levels are restricted to for example 65 dB. Although noise levels are greatly affected by the design of the conveyor support structure and conveyor covers, this may be a limiting factor in selecting the belt speed.
BELT SPEED VARIATION
The energy consumption of belt conveyor systems varies with variation of the belt speed, as will be shown in Section 3. The belt velocity can be adjusted with bulk material flow supplied at the loading point to save energy. If the belt is operating at full tonnage then it should run at the high (design) belt speed. The belt speed can be adjusted (decreased) to the actual material (volume) flow supplied at the loading point. This will maintain a constant filling of the belt trough and a constant bulk material load on the belt. A constant filling of the belt trough yields an optimum loading-ratio, and lower energy consumption per unit of conveyed material may be expected. The reduction in energy consumption will be at least 10% for systems where the belt speed is varied compared to systems where the belt speed is kept constant [8].
Varying the belt speed with supplied bulk material flow has the following advantages:
Less belt wear at the loading areas
Lower noise emission
Improved operating behavior as a result of better belt alignment and the avoidance of belt lifting in concave curve by reducing belt tensions
Drawbacks include:
Investment cost for controllability of the drive and brake systems
Variation of discharge parabola with belt speed variation
Control system required for controlling individual conveyors in a conveyor system
Constant high belt pre-tension
Constant high bulk material load on the idler rolls
An analysis should be made of the expected energy savings to determine whether it is worth the effort of installing a more expensive, more complex conveyor system.
ENERGY CONSUMPTION
Clients may request a specification of the energy consumption of a conveyor system, for example quantified in terms of maximum kW-hr/ton/km, to transport the bulk solid material at the design specifications over the projected route. For long overland systems, the energy consumption is mainly determined by the work done to overcome the indentation rolling resistance [9]. This is the resistance that the belt experiences due to the visco-elastic (time delayed) response of the rubber belt cover to the indentation of the idler roll. For in-plant belt conveyors, work done to overcome side resistances that occur mainly in the loading area also affects the energy consumption. Side resistances include the resistance due to friction on the side walls of the chute and resistance that occurs due to acceleration of the material at the loading point.
The required drive power of a belt conveyor is determined by the sum of the total frictional resistances and the total material lift. The frictional resistances include hysteresis losses, which can be considered as viscous (velocity dependent) friction components. It does not suffice to look just at the maximum required drive power to evaluate whether or not the energy consumption of a conveyor system is reasonable. The best method to compare the energy consumption of different transport systems is to compare their transport efficiencies.
TRANSPORT EFFICIENCY
There are a number of methods to compare transport efficiencies. The first and most widely applied method is to compare equivalent friction factors such as the DIN f factor. An advantage of using an equivalent friction factor is that it can also be determined for an empty belt. A drawback of using an equivalent friction factor is that it is not a 'pure' efficiency number. It takes into account the mass of the belt, reduced mass of the rollers and the mass of the transported material. In a pure efficiency number, only the mass of the transported material is taken into account.
The second method is to compare transportation cost, either in kW-hr/ton/km or in $/ton/km. The advantage of using the transportation cost is that this number is widely used for management purposes. The disadvantage of using the transportation cost is that it does not directly reflect the efficiency of a system.
The third and most "pure" method is to compare the loss factor of transport [10]. The loss factor of transport is the ratio between the drive power required to overcome frictional losses (neglecting drive efficiency and power loss/gain required to raise/lower the bulk material) and the transport work. The transport work is defined as the multiplication of the total transported quantity of bulk material and the average transport velocity. The advantage of using loss factors of transport is that they can be compared to loss factors of transport of other means of transport, like trucks and trains. The disadvantage is that the loss factor of transport depends on the transported quantity of material, which implies that it can not be determined for an empty belt conveyor.
The following are loss factors of transport for a number of transport systems to illustrate the concept:
Continuous transport:
Slurry transport around 0.01
Belt conveyors between 0.01 and 0.1
Vibratory feeders between 0.1 and 1
Pneumatic conveyors around 1 0
Discontinuous transport:
Ship between 0.001 and 0.01
Train around 0.01
Truck between 0.05 and 0.1
INDENTATION ROLLING RESISTANCE
For long overland systems, the energy consumption is mainly determined by the work done to overcome the indentation rolling resistance. Idler rolls are made of a relatively hard material like steel or aluminum whereas conveyor belt covers are made of much softer materials like rubber or PVC. The rolls therefore indent the belt's bottom-cover when the belt moves over the idler rolls, due to the weight of the belt and bulk material on the belt. The recovery of the compressed parts of the belt's bottom cover will take some time due to its visco-elastic (time dependent) properties. The time delay in the recovery of the belt's bottom cover results in an asymmetrical stress distribution between the belt and the rolls, see Figure 2. This yields a resultant resistance force called the indentation rolling resistance force. The magnitude of this force depends on the visco-elastic properties of the cover material, the radius of the idler roll, the vertical force due to the weight of the belt and the bulk solid material, and the radius of curvature of the belt in curves in the vertical plane.
Figure 2: Asymmetric stress distribution between belt and roll [7].
It is important to know how the indentation rolling resistance depends on the belt velocity to enable selection of a proper belt velocity, [11].
Figure 3: Loss factor (tanb) of typical cove