钢管自动下料机的设计【定位块式托辊钢管切断机】
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河南理工大学万方科技学院本科毕业论文 英文原文Latest Developments in Belt Conveyor TechnologyM. A. AlspaughOverland Conveyor Co., Inc.Presented at MINExpo 2004Las Vegas, NV, USASeptember 27, 2004AbstractBulk 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.IntroductionAlthough 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 todays long distance conveyance requirements. The four specific topics covered will be:l Energy Efficiencyl Route Optimizationl Distributed Powerl Analysis and SimulationEnergy EfficiencyMinimizing 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 Resistancel Rubber indentation due to idler supportl Material/Belt flexure due to sag being idlersl AlignmentThese 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 OptimizationHorizontal AdaptabilityOf 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 todays 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.ODonovan & 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.TunnelingAnother 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 ConveyorsAnd 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 ConveyorAnother 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 AdaptabilitySometimes 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.Continentals 100th installation of the HAC? was a unique shiftable installation at Mexican de Caneneas heap leach pad (Figure 17).PocketliftThe 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 PowerOne 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 SimulationMany 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 StoppingWhen 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 stressesl Maximum forces on pulleysl Minimum belt stresses and material spillagel Take-up force requirementsl Take-up travel and speed requirementsl Drive slipl Breakaway torquel Holdback torquel Load sharing between multiple drivesl Material stability on an inclineIt 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 belts 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 member2. Resistances to motion which are velocity dependent (i.e. idlers)3. Viscoelastic losses due to rubber-idler indentation4. 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 PointsOne 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 andl Pluggingl Belt and Chute Damage and Abrasionl Material Degradationl Dustl Off Center Loading/SpillageIn 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 “learning 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 computational fluid dynamics (CFD).The DEM explicitly models the dynamic motion and mechanical interactions of each body or particle in the physical problem throughout a simulation and provides a detailed description of the positions, velocities, and forces acting on each body and/or particle at discrete points in time during the analysis. In the analysis, particles are modeled as shaped bodies. The bodies can interact with each other, with transfer boundary surfaces and with moving rubber conveyor belt surfaces. The contact/impact phenomena between the interacting bodies are modeled with a contact force law which has components defined in the normal and shear directions as well as rotation. The normal contact force component is generated with a linear elastic restoring component and a viscous damping term to simulate the energy loss in a normal collision. The linear elasticcomponent is modeled with a spring whose coefficient is based upon the normal stiffness of the contact bodies and the normal viscous damper coefficient is defined in terms of an equivalent coefficient of restitution (Figure 29).Figure 30 shows particles falling through a transfer chute. The colors of the particles in the visualization represent their velocity. The RED color is zero velocity while BLUE is the highest velocity. Perhaps the greatest benefit that can be derived form the use of these tools is the feeling an experienced engineer can develop by visualizing performance prior to building. From this feel, the designer can arrange the components in order to eliminate unwanted behavior. Other quantitative data can also be captured including impact and shear forces (wear) on the belt or chute walls.FutureBigger Belt ConveyorsThis paper referenced Henderson PC2 which is one of the longest single flight conventional conveyors in the world at 16.26 km. But a 19.1 km conveyor is under construction in the USA now, and a 23.5 km flight is being designed in Australia. Other conveyors 30-40 km long are being discussed in other parts of the world. Belt manufacturers have developed low rolling resistance rubber with claims of 10-15% power savings as methods to quantify indentation have become known. Together with improved installation methods and alignment, significant power efficiencies are possible.Underground coal mines and tunneling contractors will continue to use the proven concept of distributed power to their best advantage, but now at least two of the longer surface conveyors in development will be installing intermediate drives in 2005.In Germany, RWE Rheinbraun operates coal conveyors with 30,000 tph capacities and other surface coal mines have plans to soon be approaching these loads. With capacity increases, comes increases in belt speed; again demanding better installation, manufacturing tolerances and understanding of resistances and power. Each time we go longer, higher, wider or faster, we stretch the limits of our analytical tools to predict system performance. And because each conveyor is unique, the only way we have to predict performance is our numerical analysis and simulation tools. Therefore it is imperative we continue to improve our design tools as our goals get bigger. Belt Conveyors for Bulk Materials, 6th Ed, CEMAThe Conveyor Equipment Manufacturers Association (CEMA), recognizing many of the trends discussed in this paper, is currently producing the 6th Edition of the worldwide reference manual “Belt Conveyors for Bulk Materials” with longer center conveyors in mind. This is the first major revision of this manual since the 1980s and reflects the need to update design methods for todays demanding applications.中文译文输送带技术的最新发展M. A. AlspaughOverland Conveyor Co., Inc.Presented at MINExpo 2004Las Vegas, NV, USASeptember 27, 2004摘要大量的物质运输需求在促使带式输送机继续朝大运量、长距离、多路径发展。为满足生产力的发展，在系统设计、分析和数值模拟等领域需要更多重要的技术革新。在这里我们将回顾一些复杂的、利用数学工具来保证其可靠性和适用性的实例。绪论尽管这篇文章的标题指出将会展现给大家带式输送机“新的”发展技术，但当中的大多数的思想和方法早已经四处流传了。恐怕其中任何一个的简单设备或想法对大多数人都不是“新的”。 所谓“新的”东西就是一个在成熟的条件下建立的复杂、重要的系统，是在一个系统检测(试运转)之前对系统性能的精确计算机模拟能力的提高。因而，我们讨论的主要焦点是，复杂带式输送机系统设计的最新发展，以及针对长距离运输的设计和优化。四个被涵盖的主题是：l 能量利用效率l 线路优化l 动力分配l 分析和仿真能量利用率将总耗电量降到最小不论对于带式输送机还是其它项目都是问题的关键。尽管地面大运量运输时利用带式输送机总是效率很高的手段，还是有很多方法来降低其能量需求。带式输送机的运行阻力由以下几部分组成：l 托辊阻力l 胶带与托辊架挤压l 胶带垂度的影响l 调心托辊的影响这些阻力加上其它各种次要的阻力以及用来克服重力的升力，就形成所需总共的动力。在一条 400 m 长度的典型厂内输送机中，动力可能依照图 1 被分成几部分，其中运输提升所需的动力是其中最大的一块，而所有摩擦阻力又占它的了多半数。对于大倾角输送机, 例如煤矿井下带式输送机,动力可能依照图 2 所示分配，其中用于提升的动力占了极大的一部分。 因为没有方法减少重力的影响，所以就没有方法能显著地减少在大倾角带式输送机上的动力消耗。但是在长距离地面输送机中，动力组成的几个部分就与图3所示较为相似，动力几乎全都消耗在摩擦阻力上。所以在这种情况下应特别关注带式输送机的主要阻力。有关详细的动力计算在这里不做赘述，但值得关注的是，对于托辊、胶带、调心、物料/胶带弯曲这四方面近年来已完成许多有意义的研究工作。对于各个具体方面的问题如何处理，虽然仁者见仁、智者见智，但通常大家都认为，将着眼点放在主要阻力上对整个工程的经济性是重要且必需的。在 2004 SME 年会上,MAN Takraf 的WalterKung 介绍了一篇题为“亨德森粗矿石运输系统运行、启动、操作评估”的论文。 这个工程于 1999 年12月启动，是由一条 24公里(3段)的地面输送系统来代替地下挖掘碾磨轨道拖运系统。这个系统 (PC2) 中的最长运送机长16.28 公里，提升高度475 m 。系统最重要的工况是使带空载运转时需要50% 的额定功率(约4000 千瓦，在1783 mtph 和 4.6 m/s时)，这时功率效率达到临界值。要把注意力集中在托辊, 覆盖胶和调心上。 一种判断效率上的相对差异的方法是使用 DIN(德国工业标准) 22101 标准定义中的 等效磨擦因数f ，就如比较各个主要阻力的相对差异的方法一样。过去，用于设计输送机的典型f值DIN规定为0.016左右，但 MAN Takraf 估计以他们对动力情况的了解，允许他们将f值降低30，达到0.011。该值的减少会给设备的基本投资节省一笔不小的开支。试运行后，6次换档的实测结果显示，f值为0.0075，或是更小，比期望值低30左右。 Kung说，只将f从期望值减少每年就会节省电费$100,000。路径最优化水平运输的适用性 当然，从一处到另一处运送物料最有效的方法是尽可能直接地运输。但是当我们用输送机长距离连续输送时,由于人为或自然的原因，能在直线运输的可能性少之又少。第一台水平曲线式输送机的安装在数年以前，但是今天几乎每一台安装的地面输送机都至少有一个水平方向的变化。而且今天的技术允许设计者相对容易地调整这些曲线。 图 5 和 6 显示在中国天津港务局，一条今年安装的地面带式输送机正将煤从仓库运送到装船机。 这条9 公里的带式输送机由 E.J.ODonovan与 Associates 设计、澳大利亚的Continental Conveyor 公司制造，运量为6000 mtph ，驱动功率为4 x1500 kW。 位于美国怀俄明州Powder River 盆地的Wyodak矿井,是自1923年美国有年产量记录以来最老的煤矿，而且如今还在不断地产煤。它现在利用一台水平半径为700 m(2,300 ft) 地面带式输送机(图 7) ，新煤坑离厂 756 m (2,482 英尺)。这证明受益于水平转向，带式输送机不需要非常的长。隧道 如果没有水平曲线，建造隧道就不能利用带式输送机了。全世界都在挖掘隧道，以作为下水道或是运输等基础设施。将挖掘隧道时产生的弃渣运出，最有效的方法是在隧道钻机的尾部连接一个推进式带式输送机。但很少有隧道是笔直的。例如，西班牙巴塞罗那的地下有一条直径为 10.9 m 隧道，它是伦敦地铁系统的延伸。Continental Conveyor 公司安装了如图 8 、9所示的第一个4.7 公里输送机，而且最近已经接受负责安装第二个 8.39 公里的输送机。Frontier Kemper Construction 正开始为Metropolitan St. Louis (位于密苏里州)的排水区挖掘一条6.18 公里(20,275 英尺) 长、3.6 m(12英尺)宽的隧道。 这个名为Baumgartner 的隧道(图 10) 将会装备一个长6.1 公里、带宽600 毫米、具有4个中间传动装置的带式输送机。管状输送机如果传统的输送机不能够满足半径的要求, 就可用其他带式运送机的变体例如管状带式输送机。简单的描述一下，一个管状输送机由一个卷成桶状的传送带与辊子组成。这种很基本的设计方法可以使物料被输送带完全包起来，直接产生较高的效益。托辊在各方向约束着胶带，就允许胶带朝各个方向较大地弯曲。 曲线可能是水平的，垂直的或二者的结合。而传统的输送机只能靠胶带和托辊的重力和摩擦力保证运输路径。管状输送机的另一个好处是能减少粉尘及洒漏，因为物料是完全被封闭的。这有一个经典的例子，在美国犹他州的Skyline 矿中(图 12)，路径与周围环境很好的适应. 这条3.38 公里(11,088 英尺)长的管状输送机是由ThyssenKrupp Robins 安装，穿过一个国家森林，而且中间水平换向22次、竖直换向45次。Metso钢绳输送机Metso钢绳输送机(MRC)是另一种从传统型变化而来输送机，人们一般称它为钢绳牵引输送机。这一产品以长距离输送闻名，世界最长的刮板式输送机在澳大利亚的 Worsley Alumina ，长度为30.4千米。它的牵引体与承载体是分开的(图 13)。垂直的适用性有时物质的需要被升起或降落，而常规的输送机的倾角被限制在16-18 度。 但是带式输送机的再一次突破常规的变化使带式输送机可以成功地增大倾角，甚至可以垂直输送。大倾角输送机 (HAC)大倾角输送机的第一台样机由Continental Conveyor & Equipment Co.制造出来，它用的是常规的部件、非常规的手段(图16)。人们认为采用这种方法，物料夹在两层输送带之间，整个输送机看起来就像一个大的三明治。Continental公司安装制造的第100台大倾角输送机是一种独特的、可拆移的输送机，它位于墨西哥的Mexican de Canenea 矸石过滤堆(图 17).Pocketlift图 18展示另一条非常规设计的输送带，它能用来垂直运输。这一条 Metso Pocketlift 输送带由Frontier Kemper Constructors 于2001年安装在 White County 的 Pattiki 2号井(图19)，现在它的运量是1,818 mtph，可将煤提升 273 m(895 英尺) 。动力分配当下有关带式输送机新技术的研究，最热门的内容应该数整个路线的动力分配问题了。将驱动装置布置在输送机头部和尾部，然后只让尾部驱动装置负责拉回输送带，这对于长距离带式输送机是不常见的。但现在的设计思想已发展成为允许设计者将动力布置在最需要的地方。将动力布置在带式输送机的多个部位的想法很早以前就有了。第一次在美国应用是在1974年，Kaiser煤矿。不久，地下矿井开始合并，长壁开采的煤矿的产量得到极大提高。其中采矿设备效率和性能的提高是非常引人注目的。矿工们正在寻找方法增大采区，以减少将采煤设备从一个采区搬到另一个采区所花费的时间。这样，煤区表面宽度与长度也不断增加。当矩形采煤区的长度增加时，就应注意一下运输条件。当长度增加到45千米时，输送机对动力与胶带强度的需要增加到前所未有的程度。问题包括：如此大尺寸的大功率驱动装置别说搬运了，即使皮带(传动)装置技术可以满足增加的强度需求,也意味着要费很大劲来回搬运传动装置，更重要的是要用硫化接头。由于长壁开采区的输送机需要经常改变长度，矿工们总是不停地从系统中增加或取去皮带传动装置的托辊。时间浪费更加严重。但现在需要超越了风险，而且广泛采用中间传动装置限制了皮带中的张力过大，并允许采用纤维带。今天, 中间驱动技术已被人们接受而且广泛地应用于地下矿井。世界上多数矿井经将它纳入他们当前和未来的开采计划以增加他们所有的开采工作的效率。 图20中的张力图简单地说明了带式输送机中间传动装置的主要优点。头部驱动输送机有一条简单的张力分布曲线，如图中黑线所示。虽然在一周张力平均值大约只有峰值的
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