鋼坯火焰清理機(jī)的鋼坯輸送系統(tǒng)設(shè)計,鋼坯火焰清理機(jī)的鋼坯輸送系統(tǒng)設(shè)計,鋼坯,火焰,清理,清算,輸送,系統(tǒng),設(shè)計 湘潭大學(xué)機(jī)械工程學(xué)院畢業(yè)設(shè)計工作中期檢查表 系 機(jī)制系 專業(yè) 機(jī)械設(shè)計制造及其自動化 班級 07興湘機(jī)一班 姓 名 李 珂 學(xué) 號 2007964224 指導(dǎo)教師 胡自化 指導(dǎo)教師職稱 教授 題目名稱 鋼坯火焰清理機(jī)的設(shè)計—總體方案設(shè)計和總體裝配 題目來源 ■科研 企業(yè) 其它 課題名稱 鋼坯火焰清理機(jī)的設(shè)計—總體方案設(shè)計和總體裝配 題目性質(zhì) 工程設(shè)計 ■ 理論研究 科學(xué)實(shí)驗 軟件開發(fā) 綜合應(yīng)用 其它 資料情況 1、選題是否有變化 有 ■否 2、設(shè)計任務(wù)書 ■有 否 3、文獻(xiàn)綜述是否完成 ■完成 未完成 4、外文翻譯 ■完成 未完成 由 學(xué) 生 填 寫 目前研究設(shè)計到何階段、進(jìn)度狀況： 通過對資料的查詢，已經(jīng)確定了鋼坯火焰清理機(jī)初步設(shè)計方案?，F(xiàn)階段著力對各個構(gòu)件外形設(shè)計和計算。與此同時還通過對一些復(fù)雜的裝配圖形的裝配和仿真熟悉和了解三維制圖軟件 由 老 師 填 寫 工作進(jìn)度預(yù)測（按照任務(wù)書中時間計劃） 提前完成 按計劃完成 拖后完成 無法完成 工作態(tài)度（學(xué)生對畢業(yè)論文的認(rèn)真程度、紀(jì)律及出勤情況）： 認(rèn)真 較認(rèn)真 一般 不認(rèn)真 質(zhì)量評價（學(xué)生前期已完成的工作的質(zhì)量情況） 優(yōu) 良 中 差 指導(dǎo)教師（簽名）： 年 月 日 建議檢查結(jié)果： 通過 限期整改 緩答辯 系意見： 簽名： 年 月 日 注：1、該表由指導(dǎo)教師和學(xué)生填寫。 2、此表作為附件裝入畢業(yè)設(shè)計（論文）資料袋存檔。 湘潭大學(xué)興湘學(xué)院 畢業(yè)論文（設(shè)計）任務(wù)書 設(shè)計（論文）題目： 鋼坯火焰清理機(jī)的鋼坯輸送系統(tǒng) 學(xué) 號： 2007964224 姓名 李 珂 專 業(yè)： 機(jī)械設(shè)計制造及其自動化 指導(dǎo)教師： 胡自化 系主任： 一、主要內(nèi)容及基本要求： 1、鋼坯運(yùn)送方案確定； 2、滾筒輸送機(jī)傳動方案確定； 3、滾筒輸送機(jī)動力系統(tǒng)設(shè)計； 4、滾筒輸送機(jī)傳動系統(tǒng)設(shè)計； 5、完成畢業(yè)論文的文稿工作，要求：使用A4編輯及打印裝訂成冊； 6、技術(shù)圖紙：滾筒輸送機(jī)裝配圖1張（0號）、減速器齒輪軸圖1張（3號）、電動機(jī)圖1張（3號）； 7、翻譯英文技術(shù)資料：翻譯國外滾筒輸送機(jī)相關(guān)課題的英文資料。要求：3000單詞，復(fù)印原稿與翻譯(打印)稿同冊裝訂。 二、重點(diǎn)設(shè)計的問題： 1、 滾筒輸送機(jī)傳動方案設(shè)計； 2、 滾筒輸送機(jī)傳動系統(tǒng)設(shè)計； 3、 滾筒輸送機(jī)動力系統(tǒng)設(shè)計； 三、進(jìn)度安排 各階段完成的內(nèi)容 起止時間 1 熟悉課題及基礎(chǔ)資料 第一周 2 調(diào)研及收集資料 第二周 3 方案設(shè)計與討論 第三~四周 4 初步方案可行性討論 第五~八周 5 CAD軟件學(xué)習(xí) 第九周 6 CAD制圖 第十周 7 撰寫說明書 第十一周 四、應(yīng)收集的資料及主要參考文獻(xiàn) [1]彭萬喜，胡英強(qiáng).廠內(nèi)運(yùn)輸機(jī)械.武漢：華中科技大學(xué)出版社，2006. [2]濮良貴，紀(jì)名剛.機(jī)械設(shè)計.北京：高等教育出版社，2008. [3]吳宗澤，羅圣國.機(jī)械設(shè)計課程設(shè)計手冊.北京：高等教育出版社，2006,23 . [4]機(jī)械手冊聯(lián)合編寫組.機(jī)械設(shè)計手冊（上冊，第一分冊）.北京：化學(xué)工業(yè)出版社 [5]機(jī)械手冊聯(lián)合編寫組.機(jī)械設(shè)計手冊（上冊，第二分冊）.北京：化學(xué)工業(yè)出版社 [6]機(jī)械手冊聯(lián)合編寫組.機(jī)械設(shè)計手冊（中冊，第一分冊）.北京：化學(xué)工業(yè)出版社 湘潭大學(xué)興湘學(xué)院 畢業(yè)設(shè)計說明書 題 目： 學(xué) 院： 興湘學(xué)院 專 業(yè)： 機(jī)械設(shè)計制造及其自動化 學(xué) 號： 2007964224 姓 名： 李 珂 指導(dǎo)教師： 胡自化 完成日期： 2011年05月31日 湘潭大學(xué)興湘學(xué)院 畢業(yè)設(shè)計 題 目： 學(xué) 院： 興湘學(xué)院 專 業(yè)： 機(jī)械設(shè)計制造及其自動化 學(xué) 號： 2007964224 姓 名： 李 珂 指導(dǎo)教師： 胡自化 完成日期： 2011年05月31日 湘 潭 大 學(xué) 興湘學(xué)院 本科畢業(yè)設(shè)計開題報告 題 目 鋼坯火焰清理機(jī)之鋼坯輸送系統(tǒng)設(shè)計 姓 名 李珂 學(xué)號 2007964224 專 業(yè) 機(jī)械設(shè)計制造及其自動化 班級 興湘學(xué)院機(jī)械一班 指導(dǎo)教師 胡自化 職稱 教授 填寫時間 2011年3月20 日 2011年3月  說 明 1．根據(jù)湘潭大學(xué)《畢業(yè)設(shè)計(論文)工作管理規(guī)定》，學(xué)生必須撰寫《畢業(yè)設(shè)計（論文）開題報告》，由指導(dǎo)教師簽署意見，系主任批準(zhǔn)后實(shí)施。 2．開題報告是畢業(yè)設(shè)計（論文）答辯委員會對學(xué)生答辯資格審查的依據(jù)材料之一。學(xué)生應(yīng)當(dāng)在畢業(yè)設(shè)計（論文）工作前期內(nèi)完成，開題報告不合格者不得參加答辯。 3．畢業(yè)設(shè)計(論文)開題報告各項內(nèi)容要實(shí)事求是，逐條認(rèn)真填寫。其中的文字表達(dá)要明確、嚴(yán)謹(jǐn)，語言通順，外來語要同時用原文和中文表達(dá)。第一次出現(xiàn)縮寫詞，須注出全稱。 4．本報告中，由學(xué)生本人撰寫的對課題和研究工作的分析及描述，應(yīng)不少于2000字。 5．開題報告檢查原則上在第2～4周完成，各系完成畢業(yè)設(shè)計開題檢查后，應(yīng)寫一份開題情況總結(jié)報告。 6. 填寫說明： (1) 課題性質(zhì)：可填寫A．工程設(shè)計；B．論文；C. 工程技術(shù)研究；E.其它。 (2) 課題來源：可填寫A．自然科學(xué)基金與部、省、市級以上科研課題；B．企、事業(yè)單位委托課題；C．校級基金課題；D．自擬課題。 (3) 除自擬課題外，其它課題必須要填寫課題的名稱。 (4) 參考文獻(xiàn)不能少于10篇。 (5) 填寫內(nèi)容的字體大小為小四，表格所留空不夠可增頁。本科畢業(yè)設(shè)計(論文)開題報告 學(xué)生姓名 李珂 學(xué) 號 2007964224 專 業(yè) 機(jī)械設(shè)計制造及其自動化 指導(dǎo)教師 胡自化 職 稱 教授 所在系 機(jī)制系 課題來源 科研 課題性質(zhì) 工程技術(shù)研究 課題名稱 鋼坯火焰清理機(jī)之鋼坯輸送系統(tǒng)設(shè)計 一、選題的依據(jù)、課題的意義及國內(nèi)外基本研究情況 鋼坯火焰清理(searfing of billet)利用高溫火焰的氣割和熔除作用將鋼坯表面缺陷燒除。在鈉坯生產(chǎn)中，它是保證鋼坯質(zhì)量的重要工序。它是通過專門燒嘴將氧氣和煉焦煤氣進(jìn)行混合，燃燒火焰預(yù)熱連鑄鋼坯，然后利用高壓的純氧流與鋼坯表面產(chǎn)生氧化反應(yīng)，對鋼坯的一個頂面、一個底面和兩個側(cè)面的表面缺陷進(jìn)行火焰清理作業(yè)。 鋼坯火焰清理技術(shù)起源于美國，成熟于韓國，是全球冶金行業(yè)率先進(jìn)行批量化檢驗板坯皮下缺陷的先進(jìn)手段，目前正風(fēng)靡于世界冶金業(yè)。國外鋼坯火焰清理技術(shù)現(xiàn)處于極度保密的狀態(tài)，國內(nèi)需要花費(fèi)巨大的外匯來進(jìn)口國外的鋼坯火焰清理機(jī)的整機(jī)和關(guān)鍵核心部件，而且維修服務(wù)費(fèi)用昂貴。 基于我國目前火焰清理機(jī)研發(fā)十分落后的局面，注定我國民族冶金企業(yè)必須走自主創(chuàng)新、產(chǎn)學(xué)研相結(jié)合的道路，通過對鋼坯火焰清理機(jī)研發(fā)中的整體方案設(shè)計、結(jié)構(gòu)分析、制造與裝配等關(guān)鍵技術(shù)進(jìn)行校企聯(lián)合公關(guān)，我國才能夠較快較全面掌握鋼坯火焰清理技術(shù)，為我國冶金企業(yè)長期發(fā)展注入強(qiáng)勁的活力。因此，鋼坯火焰清理機(jī)的設(shè)計項目具有十分深遠(yuǎn)的現(xiàn)實(shí)意義和工程應(yīng)用價值。 二、研究內(nèi)容、預(yù)計達(dá)到的目標(biāo)、關(guān)鍵理論和技術(shù)、技術(shù)指標(biāo)、完成課題的方案和主要措施 火焰清理機(jī)的輸送系統(tǒng)能將鋼坯穩(wěn)定的輸送到清理區(qū)域以及冷卻區(qū)域。在輸送過程中必須保持鋼坯的穩(wěn)定輸送。因此，為滿足鋼坯輸送工序要求和項目技術(shù)指標(biāo)要求，鋼坯輸送系統(tǒng)應(yīng)具有如下功能： 1、鋼坯的穩(wěn)定輸送功能 2、鋼坯的準(zhǔn)確定位功能 3、鋼坯的支撐功能 技術(shù)指標(biāo)： 1、鋼坯的輸送速度為19.38m/min 2、將軋后的鋼坯在熱狀態(tài)下同時進(jìn)行四面(方坯)或兩面(板坯)的在線火焰清理 鋼坯輸送系統(tǒng)采用驅(qū)動式滾筒輸送機(jī)，并且采用準(zhǔn)齒輪傳動，能使鋼坯穩(wěn)定的輸送到需要的區(qū)域，以便對其進(jìn)行清理。 完成課題的方案和主要措施：先在導(dǎo)師的幫助下查閱相關(guān)的資料，對課題進(jìn)行初步的了解，然后通過分析計算對它做前面的了解，先通過三維軟件對之進(jìn)行動態(tài)仿真，看所設(shè)計的參數(shù)是否合理，最后將此產(chǎn)品研發(fā)出來。 三、主要特色及工作進(jìn)度 主要特色： 利用計算機(jī)輔助設(shè)計技術(shù)，基于solidworks軟件對理論設(shè)計的進(jìn)行參數(shù)化建模。 工作進(jìn)度： 收集查閱了有滾筒輸送機(jī)設(shè)計資料，現(xiàn)已經(jīng)對方案進(jìn)行了初步的討論。接下來將進(jìn)行方案的選取與確定，并制定了設(shè)計提綱方案和計劃，將按照計劃實(shí)施。 四、主要參考文獻(xiàn)（按作者、文章名、刊物名、刊期及頁碼列出） [1]彭萬喜，胡英強(qiáng).廠內(nèi)運(yùn)輸機(jī)械[M].武漢：華中科技大學(xué)出版社，2006. [2]濮良貴，紀(jì)名剛.機(jī)械設(shè)計[M].北京：高等教育出版社，2008. [3]吳宗澤，羅圣國.機(jī)械設(shè)計課程設(shè)計手冊[M].北京：高等教育出版社， . [4]機(jī)械手冊聯(lián)合編寫組.機(jī)械設(shè)計手冊[M]（上冊，第一分冊）.北京：化學(xué)工業(yè)出版社 [5]機(jī)械手冊聯(lián)合編寫組.機(jī)械設(shè)計手冊[M]（上冊，第二分冊）.北京：化學(xué)工業(yè)出版社 [6]機(jī)械手冊聯(lián)合編寫組.機(jī)械設(shè)計手冊[M]（中冊，第一分冊）.北京：化學(xué)工業(yè) 出版社 指導(dǎo)教師 意 見 指導(dǎo)教師簽名： 年 月 日 系意見 系主任簽名： 年 月 日 院意見 教學(xué)院長簽名： 年 月 日 湘潭大學(xué)興湘學(xué)院 畢業(yè)論文（設(shè)計）評閱表 學(xué)號 2007964224 姓名 李 珂 專業(yè) 機(jī)械設(shè)計制造及其自動化 畢業(yè)論文（設(shè)計）題目： 鋼坯火焰清理機(jī)鋼坯輸送系統(tǒng) 評價項目 評 價 內(nèi) 容 選題 1.是否符合培養(yǎng)目標(biāo)，體現(xiàn)學(xué)科、專業(yè)特點(diǎn)和教學(xué)計劃的基本要求，達(dá)到綜合訓(xùn)練的目的； 2.難度、份量是否適當(dāng)； 3.是否與生產(chǎn)、科研、社會等實(shí)際相結(jié)合。 能力 1.是否有查閱文獻(xiàn)、綜合歸納資料的能力； 2.是否有綜合運(yùn)用知識的能力； 3.是否具備設(shè)計方案的設(shè)計能力、設(shè)計方法和手段的運(yùn)用能力； 4.是否具備一定的外文與計算機(jī)應(yīng)用能力； 5.工科是否有經(jīng)濟(jì)分析能力。 論文 （設(shè)計）質(zhì)量 1.立論是否正確，論述是否充分，結(jié)構(gòu)是否嚴(yán)謹(jǐn)合理；實(shí)驗是否正確，設(shè)計、計算、分析處理是否科學(xué)；技術(shù)用語是否準(zhǔn)確，符號是否統(tǒng)一，圖表圖紙是否完備、整潔、正確，引文是否規(guī)范； 2.文字是否通順，有無觀點(diǎn)提煉，綜合概括能力如何； 3.有無理論價值或?qū)嶋H應(yīng)用價值，有無創(chuàng)新之處。 綜 合 評 價 評閱人： 2011年5月 日 河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文 英文原文 Latest Developments in Belt Conveyor Technology M. A. Alspaugh Overland Conveyor Co., Inc. Presented at MINExpo 2004 Las Vegas, NV, USA September 27, 2004 Abstract Bulk material transportation requirements have continued to press the belt conveyor industry to carry higher tonnages over longer distances and more diverse routes. In order keep up, significant technology advances have been required in the field of system design, analysis and numerical simulation. Examples of complex conveying applications along with the numerical tools required to insure reliability and availability will be reviewed. Introduction Although the title of this presentation indicates “new” developments in belt conveyor technology will be presented, most of the ideas and methods offered here have been around for some time. We doubt any single piece of equipment or idea presented will be “new” to many of you. What is “new” are the significant and complex systems being built with mostly mature components ，what is also “new” is the increasing ability to produce accurate computer simulations of system performance prior to the first system test (commissioning). As such, the main focus of this presentation will be the latest developments in complex system design essential to properly engineer and optimize today’s long distance conveyance requirements. The four specific topics covered will be: l Energy Efficiency l Route Optimization l Distributed Power l Analysis and Simulation Energy Efficiency Minimizing overall power consumption is a critical aspect of any project and belt conveyors are no different. Although belt conveyors have always been an efficient means of transporting large tonnages as compared to other transport methods, there are still various methods to reduce power requirements on overland conveyors. The main resistances of a belt conveyor are made up of: l Idler Resistance l Rubber indentation due to idler support l Material/Belt flexure due to sag being idlers l Alignment These resistances plus miscellaneous secondary resistances and forces to over come gravity (lift) make up the required power to move the material. In a typical in-plant conveyor of 400m length, power might be broken into its components as per Figure 1 with lift making up the largest single component but all friction forces making up the majority. In a high incline conveyor such as an underground mine slope belt, power might be broken down as per Figure 2, with lift contributing a huge majority. Since there is no way to reduce gravity forces, there are no means to significantly reduce power on high incline belts. But in a long overland conveyor, power components will look much more like Figure 3, with frictional components making up almost all the power. In this case, attention to the main resistances is essential. The specifics of power calculation is beyond the scope of this paper but it is important to note that significant research has been done on all four areas of idlers, rubber indentation, alignment and material/belt flexure over the last few years. And although not everyone is in agreement as to how to handle each specific area, it is generally well accepted that attention to these main resistances is necessary and important to overall project economics. At the 2004 SME annual meeting, Walter Kung of MAN Takraf presented a paper titled “The Henderson Coarse Ore Conveying System- A Review of Commissioning, Start-up and Operation”2. This project was commissioned in December 1999 and consisted of a 24 km (3 flight) overland conveying system to replace the underground mine to mill rail haulage system. The longest conveyor in this system (PC2) was 16.28 km in length with 475m of lift. The most important system fact was that 50% of the operating power (~4000 kW at 1783 mt/h and 4.6 m/s) was required to turn an empty belt therefore power efficiency was critical. Very close attention was focused on the idlers, belt cover rubber and alignment. One way to document relative differences in efficiency is to use the DIN 22101 standard definition of “equivalent friction factor- f” as a way to compare the total of the main resistances. In the past, a typical DIN fused for design of a conveyor like this might be around 0.016. MAN Takraf was estimating their attention to power would allow them to realize an f of 0.011, a reduction of over 30%. This reduction contributed a significant saving in capital cost of the equipment. The actual measured results over 6 operating shifts after commissioning showed the value to be 0.0075, or even 30% lower than expected. Mr. Kung stated this reduction from expected to result in an additional US$100, 000 savings per year in electricity costs alone. Route Optimization Horizontal Adaptability Of course the most efficient way to transport material from one point to the next is as directly as possible. But as we continue to transport longer distances by conveyor, the possibility of conveying in a straight line is less and less likely as many natural and man-made obstacles exist. The first horizontally curved conveyors were installed many years ago, but today it seems just about every overland conveyor being installed has at least one horizontal change in direction. And today’s technology allows designers to accommodate these curves relatively easily. Figures 5 and 6 shows an overland conveyor transporting coal from the stockpile to the ship loader at the Tianjin China Port Authority installed this year. Designed by E.J.O’Donovan & Associates and built by Continental Conveyor Ltd of Australia, this 9 km overland carries 6000 mtph with 4x1500 kW drives installed. The Wyodak Mine, located in the Powder River Basin of Wyoming, USA, is the oldest continuously operating coal mine in the US having recorded annual production since 1923. It currently utilizes an overland (Figure 7) from the new pit to the plant 756m long (2,482 ft) with a 700m (2,300 ft) horizontal radius. This proves a conveyor does not need to be extremely long to benefit from a horizontal turn. Tunneling Another industry that would not be able to use belt conveyors without the ability to negotiate horizontal curves is construction tunneling. Tunnels are being bore around the world for infrastructure such as waste water and transportation. The most efficient method of removing tunnel muck is by connecting an advancing conveyor to the tail of the tunnel boring machine. But these tunnels are seldom if ever straight. One example in Spain is the development of a 10.9m diameter tunnel under Barcelona as part of the Metro (Train) Extension Project. Continental Conveyor Ltd. installed the first 4.7km conveyor as shown in Figures 8 and 9 and has recently received the contract to install the second 8.39 km conveyor. In another example, Frontier Kemper Construction is currently starting to bore 6.18 km (20,275 ft) of 3.6m (12 foot) diameter tunnel for the Metropolitan St. Louis (Missouri) Sewer District. The Baumgartner tunnel (Figure 10) will be equipped with a 6.1 km conveyor of 600mm wide belting with 4 intermediate drives. Pipe Conveyors And if conventional conveyors cannot negotiate the required radii, other variations of belt conveyor such as the Pipe Conveyor might be used. In its simplest description, a pipe conveyor consists of a rubber conveyor belt rolled into a pipe shape with idler rolls. This fundamental design causes the transported material to be totaled enclosed by the belt which directly creates all the advantages. The idlers constrain the belt on all sides allowing much tighter curves to be negotiated in any direction. The curves can be horizontal, vertical or combinations of both. A conventional conveyor has only gravity and friction between the belt and idlers to keep it within the conveyance path. Another benefit of pipe conveyor is dust and/or spillage can be reduced because the material is completely enclosed. A classic example where both environment and adaptability to path were particularly applicable was at the Skyline Mine in UT, USA (Figure 12). This 3.38 km (11,088 ft) Pipe Conveyor was installed by Thyssen Krupp Robins through a national forest and traversed 22horizontal and 45 vertical curves. Metso Rope Conveyor Another variation from conventional is the Metso Rope Conveyor (MRC) more commonly known as Cable Belt. This product is known for long distance conveying and it claims the longest single flight conveyor in the world at Worsley Alumina in Australia at 30.4 km. With Cable Belt, the driving tensions (ropes) and the carrying medium (belt) are separated (Figure 13). Figure 15 shows a 10.4 km Cable Belt with a 430m horizontal radius at Line Creek in Canada. Vertical Adaptability Sometimes material needs to be raised or lowered and the conventional conveyor is limited to incline angles around 16-18 degrees. But again non-traditional variations of belt conveyors have been quite successful at increased angles as well as straight up. High Angle Conveyor (HAC) The first example manufactured by Continental Conveyor & Equipment Co. uses conventional conveyor components in a non-conventional way (Figure 16). The concept is known as a sandwich conveyor as the material is carried between two belts. Continental’s 100th installation of the HAC? was a unique shiftable installation at Mexican de Canenea’s heap leach pad (Figure 17). Pocketlift The second example shows a non-traditional belt construction which can be used to convey vertically (Figure 18). This Metso Pocketlift belt was installed by Frontier Kemper Constructors at the Pattiki 2 Mine of White County Coal in 2001 (Figure 19). It currently lifts 1,818 mtph of run-of-mine coal up 273 m (895 ft). Distributed Power One of the most interesting developments in technology in the recent past has been the distribution of power along the conveyor path. It has not been uncommon to see drives positioned at the head and tail ends of long conveyors and let the tail drive do the work of pulling the belt back along the return run of the conveyor. But now that idea has expanded to allow designers to position drive power wherever it is most needed. The idea of distributing power in multiple locations on a belt conveyor has been around for a long time. The first application in the USA was installed at Kaiser Coal in 1974. It was shortly thereafter that underground coal mining began consolidating and longwall mines began to realize tremendous growth in output. Mining equipment efficiencies and capabilities were improving dramatically. Miners were looking for ways to increase the size of mining blocks in order to decrease the percentage of idle time needed to move the large mining equipment from block to block. Face widths and panel lengths were increasing. When panel lengths were increased, conveyance concerns began to appear. The power and belt strengths needed for these lengths approaching 4 -5 km were much larger than had ever been used underground before. Problems included the large size of high power drives not to mention being able to handle and move them around. And, although belting technology could handle the increased strength requirements, it meant moving to steel reinforced belting that was much heavier and harder to handle and more importantly, required vulcanized splicing. Since longwall panel conveyors are constantly advancing and retreating (getting longer and shorter), miners are always adding or removing rolls of belting from the system. Now the need surpassed the risk and the application of intermediate drives to limit belt tensions and allow the use of fabric belting on long center applications was actively pursued. Today, intermediate drive technology is very well accepted and widely used in underground coal mining. Many mines around the world have incorporated it into their current and future mine plans to increase the efficiency of their overall mining operations. The tension diagram in Figure 20 shows the simple principal and most significant benefit of intermediate belt conveyor drives. This flat, head driven conveyor has a simple belt tension distribution as shown in black. Although the average belt tension during each cycle is only about 40% of the peak value, all the belting must be sized for the maximum. The large drop in the black line at the head pulley represents the total torque or power required to run the conveyor. By splitting the power into two locations (red line), the maximum belt tension is reduced by almost 40% while the total power requirement remains virtually the same. A much smaller belt can be used and smaller individual power units can be used. To extend the example further, a second intermediate drive is added (green line) and the peak belt tension drops further. The tunneling industry was also quick to adopt this technology and even take it to higher levels of complexity and sophistication. But the main need in tunneling was the necessity of using very tight horizontal curves. By applying intermediate drives (Figure 21) to an application such as the Baumgartner Tunnel as described in Figure 10 above, belt tensions can be controlled in the horizontal curves by strategically placing drives in critical locations thereby allowing the belt to turn small curves. In Figure 22, the hatched areas in green represent the location of curved structure. The blue line represents carry side belt tensions and the pink line represents return side belt tensions. Notice belt tensions in both the carry and return sides are minimized in the curves, particularly the tightest 750m radius. Although aboveground overland conveyors have not used this technology extensively to date, applications are now starting to be developed due to horizontal curve requirements. Figure 23 shows a South American, 8.5km hard rock application which requires an intermediate drive to accommodate the four relatively tight 2000m radii from the midpoint to discharge. Figure 24 shows a comparison of belt tensions in the curved areas with and without distributed power. The benefit of distributed power is also being used on the MRC Cable Belt. However, since the tension carrying ropes are separate from the load carrying belt, installing intermediate drives is even easier as the material never has to leave the carry belt surface. The tension carrying ropes are separated from the belt long enough to wrap around drive sheaves and the carry belt is set back on the ropes to continue on (Figure 25). Analysis and Simulation Many will argue the major reason for our ability to build complex conveyors as described above is advancements in the analysis and simulation tools available to the designer. A component manufacturer can usually test his product to insure it meets the specification; however the system engineer can seldom test the finished system until it is completed on site. Therefore computational methods and tools are absolutely critical to simulate the interactions of various diverse disciplines and components. Dynamic Starting and Stopping When performing starting and stopping calculations per CEMA or DIN 22101 (static analysis), it is assumed all masses are accelerated at the same time and rate; in other words the belt is a rigid body (non-elastic). In reality, drive torque transmitted to the belt via the drive pulley creates a stress wave which starts the belt moving gradually as the wave propagates along the belt. Stress variations along the belt (and therefore elastic stretch of the belt) are caused by these longitudinal waves dampened by resistances to motion as described above. Many publications since 1959 have documented that neglecting belt elasticity in high capacity and/or long length conveyors during stopping and starting can lead to incorrect selection of the belting, drives, take-up, etc. Failure to include transient response to elasticity can result in inaccurate prediction of: l Maximum belt stresses l Maximum forces on pulleys l Minimum belt stresses and material spillage l Take-up force requirements l Take-up travel and speed requirements l Drive slip l Breakaway torque l Holdback torque l Load sharing between multiple drives l Material stability on an incline It is, therefore, important a mathematical model of the belt conveyor that takes belt elasticity into account during stopping and starting be considered in these critical, long applications. A model of the complete conveyor system can be achieved by dividing the conveyor into a series of finite elements. Each element has a mass and rheological spring as illustrated in Figure 26. 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 unloading. The transfer chute is often sited as the highest maintenance area of the conveyor and many significant production risks are centered here.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. Mass Flow at Transfer Points One of the reasons for using intermediate drives and running single flight conveyors longer and longer is to eliminate transfer points. Many of the most difficult problems associated with belt conveyors center around loading and l Plugging l Belt and Chute Damage and Abrasion l Material Degradation l Dust l Off Center Loading/Spillage In the past, no analytical tools have been available to the design engineer so trial-and-error and experience were the only design methods available. Today, numerical simulation methods exist which allow designers to “test” their design prior to fabrication. Numerical simulation is the discipline of designing a model of an actual physical system, executing the model on a computer, and analyzing the results. Simulation embodies the principle of “l(fā)earning by doing''. To understand reality and all of its complexity, we build artificial objects in the computer and dynamically watch the interactions. The Discrete Element Method (DEM) is a family of numerical modeling techniques and equations specifically designed to solve problems in engineering and applied science that exhibit gross discontinuous mechanical behavior such as bulk material flow. It should be noted that problems dominated by discontinuum behavior cannot be simulated with conventional continuum based computer modeling methods such as finite element analysis, finite difference procedures and/or even comp