外文翻译-管状带式输送机的参数计算和结构设计大学论文.doc

中文3150字
英文原文
Parameters Calculation and Structure Design of Pipe Belt Conveyer
Zaimei Zhang1, Fang Zhou2, Jianheng Ji2
1School of Mechanical Engineering, University ofJinan, Jinan 250022, Shandong Province,China
2Departments ofInformation Engineering, Shandong Water Vocational College, Rizhao 276826,Shandong Province, China
Abstract: Pipe belt conveyor is a new type of special belt conveyor and it is wildly used in conveying powder material. In the paper, the advantages of pipe belt conveyor are introduced. Calculation of pipe belt conveyor s main parameters is different from that of conventional belt conveyor s. The parameters such as throughput, belt speed, belt width, resistance, tension in belt and power are described. The length of transition
section is analyzed because it is important to the belt life. Hexagon supporting rollers and tipping device are necessary parts ofpipe belt conveyor. The structures of them are also discussed.
keywords: Pipe Belt Conveyor, Transition Section,Hexagon Supporting Rollers, Tipping Device
1. Introduction
Pipe belt conveyor is a new type of special belt conveyor which developed from the conventional belt conveyor. In this conveyor, flat belt is forced to be tubular by supporting roller groups and material conveyed is enveloped in it. Therefore airproof convey is realized in whole conveyance line. Pipe belt conveyor was proposed in 1964 by Japan Pipe Conveyor (JPC), and it went into real use in 1979[1] .After that, it was rapidly developed in Gennany and America and widely used abroad. But it is not deeply studied and its' use is much limited in China.
2. The characteristics of pipe belt conveyor
Figurel is for the structure of pipe belt conveyor. The load is putted on by the feeder at the end of conveyor.
The belt is flat when it runs through the driven roller and it is conducted by a series of supporting rollers to be tubular gradually. Thus airproof conveyance is realized. In order to discharge, the pipe is also conducted by a series of supporting rollers to be flat near the driving roller. The conveyor discharges at its head. Two-way conveyance can be realized. But tipping device for belt must be added. Characteristics are obvious due to its special structure comparing with other belt conveyor[1].
(1) Unpolluted conveyance
In pipe belt conveyor, material doesn't come out and isn't influenced by environment because the belt is tubular and the two sides lap over each other. When it conveys powder, food and chemical material etc., this advantage is obvious.
(2) Big obliquity of conveyance
Obliquity can reach about 18 in the conventional belt conveyor. But in pipe belt conveyor, material is enveloped in pipe and friction between material and belt is greater than before. So obliquity can be increased to 30 The bigger obliquity is, the shorter conveyance length will be. This can result in lower cost.
(3) Two-way conveyance is convenient
Belt can be tubular in return of pipe belt conveyor and material can be conveyed in the reverse direction by special device such as special feeder and tipping device.
(4) Conveyor bed is narrow
In conveyance, bed is narrow because the cross section is a circle. The required building space and building steel are reduced. The bed cost is low and it can be used when space is limited.

3 .Main parameters calculation of pipe belt conveyor
Main parameters in pipe belt conveyor are throughput, belt width, belt speed and power. But production throughput is always given.
3.1 Calculation throughput
Throughput of conveyor can be fonnulated as follows[2]:

Where is belt speed, is the pipe area, is density of material conveyed and is coefficient of material filling, = 0.44～0.8. If material size is less than one third of pipe diameter, =0.8. If material size is one third of pipe diameter, =0.75. If material size is half of pipe diameter, =0.58. If material size is two thirds of pipe diameter, =0.44.
3.2 Belt speed
Belt speed is determined by characteristic of material, throughput, belt width and the installation method of conveyor. Generally speaking, quick belt speed is beneficial because it can reduce belt width and tension in belt when throughput is constant. This will economize on investment in belt and power consumption. Belt speed usually used is 2～5m/s[3].
3.3 Belt width
Belt width can be calculated according throughput. The belt diameter can be expressed[2]:

Where d is pipe diameter.
The lap of two sides is about one third or half of pipe diameter. When belt is tubular, the relationship between belt width and pipe diameter is as follow:

3.4 Running resistance calculation
The method has no difference in resistance calculation between pipe belt conveyor and conventional belt conveyor. Generally, Coefficient of resistance is usually used in resistance calculation. Tension in belt is calculated point by point. Extrusion force is increased because material is enveloped in pipe. Therefore coefficient of resistance in pipe belt conveyor is greater than that in conventional belt conveyor.
(1)Resistance in tangent
Resistance in belt with load[2]:

Resistance in belt without load:

Where is resistance in running, is the unit mass of belt per meter, is the average unit mass of the upper supporting rollers per meter along the belt, is the unit mass of material per meter along the belt, is the average unit mass of the below supporting rollers per meter along the belt, is the length of conveyance, is obliquity of conveyance and is coefficient of resistance in supporting rollers, showed in table 1.
Table 1.Coefficient of resistance in supporting rollers

(2) Resistance in curvature
Resistance in curvature is caused by belt ossification and friction in roller bearings. It is proportional to the tension at curvature entrance. That is[2] :

Where is the tension in belt at curvature exit, is the tension in belt at curvature entrance and is coefficient of resistance.
3.5 Tension calculation in belt
After resistance in each section has been calculated, we can calculate the tension at every point. We can divide whole path into several tangents and curvatures and number every joint before we calculate. Tension at any point is calculated by the formula as followed[2]:

Where and are tension in belt at point and point , is resistance between point and point .
The tension at driving roller entrance and driving roller exit can be obtained. Circumferential force on driving roller can be described by following expression:

Where is circumferential force on driving roller, is the tension in belt at driving roller entrance and is the tension in belt at driving roller exit.
The following condition must be satisfied because the belt do not permitted to slide on driving roller[2].

Where is the coefficient of friction between the belt and driving roller, is angle of the belt enveloping on the roller.
3.6 Power calculation
Power is mainly consumed in overcoming running resistance. And some power is used in elevating material in sloping conveyor. Power on driving roller shaft can be calculated by the follower expression[2]:

So the motor power is:

Where is a factor of safety and is transmission device efficiency.
4 Structure design of pipe belt conveyor
4.1 The length of transition section

Figure 2 Length of transition section
Transition section is shown in figure 2. The belt is flat at driving roller and driven roller. The belt is turned from flat belt into tubular one at transition section. The length of transition depends on the permissible extension of belt. If transition section is too short, additional deformation and stress will be great in both sides of belt. This will result damage to belt. If transition section is too long, distance of airproof conveyance in whole line will be shortened. Generally speaking, the length of transition section equals to 25 diameters in nylon belt while 50 diameters in wire rope belt[3].
4.2 Design of supporting rollers
Parallel supporting rollers must be used near driving roller and driven roller so that the angle of the belt enveloping on the roller is big enough. But at other position in transition section trough supporting rollers are used. Thus the flat belt can become tubular one gradually and additional stress at edge of belt can be reduced. So trough angle is usually 20°,30° ,45° ,60° and 90°. Since impact load at material entrance is inevitable, three groups of cushioning supporting rollers can sever to reduce the intensity of shock loads and its' spacing is about 300～500mm[4].
Hexagon supporting rollers are widely used after the flat belt becomes tubular onel5J • Rollers can be equipped on the same side or two sides of the supporting board. is easy to positioning rollers precisely and the force in belt is uniform when the six rollers are equipped on the same side of supporting board. Generally speaking, the adjacent rollers spacing should not exceed the belt thickness, usually 4～8mm. If the spacing were too big, the edge of belt would jam in it. There are three rollers on each side of the supporting board when rollers are equipped on two sides of it. The length of roller can be longer than the length of hexagon side and the belt can not jam in the space of adjacent rollers. On the other hand, the force in supporting board is uniform. Rollers on supporting board are shown in fig.3 and fig.4.

Figure 3 .Rollers on same side of suppporting board

Figure 4. Rollers on two side of suppporting board
Rigidity is greatly increased after flat belt becomes tubular. So supporting rollers spacing can also be increased. Supporting roller groups spacing with load is about 1.2m or 1.0m and it is 3.0m in return in conventional conveyor, while it varies with the pipe diameter in pipe belt conveyor. The greater pipe b diameter is, the greater the spacing is[5]. The relationship etween pipe diameter and the spacing is shown in table 2[5].

Table 2. The relationship between pipe diameter and supporting roller groups spacing

4.3 Belt tipping device
Remnant material on belt will pollute environment and adhere to rollers and supporting rollers after discharge. This will result to belt wear. So the same side of belt is always used when conveying material. Belt tipping device severs to overturn the belt [6]. It consists of several rollers. The belt is hold by two horizontal rollers and two vertical rollers and tum 90° Then another two horizontal rollers hold the belt and tum it 90° at the same direction. Thus belt overturn is realized. The spacing between horizontal rollers and vertical rollers depends on belt width and operation conditions.
5. Conclusion
Compared with conventional belt conveyor, pipe belt conveyor has so many advantages that it will be widely used in the future. When calculating parameters, some formals in convention belt conveyor can be used in pipe belt conveyor, but some coefficients must be modified. The power is greater in pipe belt conveyor than in conventional belt conveyor because friction is great in pipe belt conveyor. The transition section length depends on the belt type and pipe diameter. Parallel supporting rollers and trough supporting rollers in conventional belt conveyor can also be used in pipe belt conveyor, but trough angle varies with the poison where trough supporting rollers are installed. Hexagon supporting rollers and tipping device exist only in pipe belt conveyor and their structure is described in this paper. Supporting roller groups spacing also varies with pipe diameter.
References
[1] Kai Liu, "Application and Development of Pipe Belt Conveyor", Coal Technology, 2006,25(09): 19-21
[2] Maton A E, "Power and Capacity Review of Tubular Pipe and Trough Conveyor", Bulk Solids Handing, 1997,17(1):47-50
[3] Zhiping Li, "Application of Pipe Belt Conveyor in Bulk Handling", Electric Power Survey &Design,2003,1:48-52
[4] Weigang Song, Ye Yu, "The Development and Critical Techniques of the Pipe Belt Conveyor", Cement, 2005,04:42-46
[5] Yuefeng An, "Pipe belt conveyor", S P & BMH Related engineering. 2006,2:39-42
[6] Gregory A Vaka, "Pipe Conveyor---Development and Advantages", Bulk Solids Handling, 1998,18(3):451-455

中文译文
管状带式输送机的参数计算和结构设计

摘要:管状带式输送机是一种新型的专用带式输送机，它可广泛应用于粉状物料的运输。论文介绍了管状带式输送机的优点。计算了不同于普通带式输送机的管状带式输送机的主要参数。描述了管状带式输送机的输送能力、带速、带宽、摩擦阻力、胶带张紧力和功率。分析了过渡段长度，因为它对胶带寿命很重要。六边形托辊和倾翻装置是管状带式输送机的必要原件。它们的结构在论文中也进行了论述。
关键词：管状带式输送机，过渡段，六边形托辊，倾翻装置
1.绪论
管状带式输送机是在普通带式输送机基础上发展起来的一种新型专用带式输送机。在该输送机中，平直的胶带被托辊组卷成管状，物料被包在管状胶带中运输。因此可实现整个运输路线封闭运输。1964年，日本管状输送机公司研发了管状带式输送机，1979年正式投入使用。随后，该输送机在德国和美国获得了迅速发展和广泛应用。但是，中国对该输送机未进行深入研究，其应用被大大限制了。
2.管状带式输送机特性
管状带式输送机结构如图1所示。在输送机尾部的进料器将物料装载到输送机胶带上。
当胶带通过从动滚筒时，它是平直的，然后经一系列托辊引导，逐渐转变为管状。从而可以实现封闭运输。为了卸载，管状胶带也需要一系列靠近驱动滚筒的托辊引导从而转变为平直的。该输送机在其机头部卸载。它可以实现双向运输。但是必须加设倾翻装置。由于其特殊结构，与其他带式输送机相比，它的特征是很明显的[1]。
（1）清洁运输
在管状带式输送机中，物料不会泄露出来并且不受环境的影响，因为运输胶带是管状的，胶带的边缘搭接在一起。当运输粉状物料、食物和化学物料等时，该优点十分突出。
（2）大倾角运输
普通胶带运输机的倾角可以达到18°左右。但是，在管状带式输送机中，物料被包在管状胶带中，物料和胶带的摩擦力较大。因此其倾角可以增加到30°。倾角越大，运输长度将越短。这可以使成本降低。
（3）便利的双向运输
返回时，管状带式输送机胶带可以转变为管状。通过专用进料器和倾翻装置，物料可以进行反向运输。
（4）狭窄的运输机架
在管状带式输送机中，运输机架是狭窄的。因为管状胶带的横截面是圆形的。这减少了必需的建筑空间和建筑物料。运输机架成本很低，当安装空间被限制时依然可以使用。

图1 管状带式输送机结构
3.管状带式输送机主要参数计算
管状带式输送机的主要参数包括：输送能力、带宽、带速和功率。但是输送机输送能力一般都是额定的。
3.1 输送能力计算
管状带式输送机的输送能力可以用下式表示[2]：

式中，—带速；
—胶带圆管截面积；
—物料堆积密度；
—装料充满系数，取0.44～0.8。当物料块度尺寸<1/3管径时， =0.8；当物料块度尺寸=1/3管径时， =0.75；当物料块度尺寸=1/2管径时， =0.58；当物料块度尺寸=2/3管径时， =0.44。
3.2 带速
管状带式输送机的带速由物料特性、输送能力、带宽和输送机安装方式决定。一般而言，较快的带速是有利的，因为当输送能力额定时，它可以减小带宽和胶带张紧力。这可以节省胶带材料和降低能量消耗。带速一般取2～5m/s[3]。
3.3 带宽
带宽可以根据输送能力计算。胶带管径可以表示为：

式中，—胶带管径。
胶带边缘搭接长度大约为1/3～1/2管径。当胶带是管状时，带宽和胶带管径关系如下：

3.4 运行摩擦阻力计算
管状带式输送机摩擦阻力的计算方法和普通带式输送机摩擦阻力的计算方法一样。一般，摩擦系数常用于摩擦阻力计算。胶带张紧力逐点计算出来。因为物料被包在管状胶带中，增加了对胶带的挤压力。因此，管状带式输送机摩擦系数比普通带式输送机大。
（1）切向摩擦阻力
加载时胶带摩擦阻力[2]：

卸载时胶带摩擦阻力

式中，—运行摩擦阻力；
—每米胶带质量；
—上部托辊沿胶带每米平均质量；
—物料沿胶带每米质量；
—下部托辊沿胶带每米平均质量；
—带式输送机长度；
—带式输送机倾角；
—托辊摩擦系数，见表1。

表1 托辊摩擦系数
环 境
平直托辊
槽形托辊
六边形托辊
清洁、干燥和无灰尘的户内
0.018
0.02
0.035～0.045
正常温度下少量灰尘
0.025
0.03
0.045～0.055
大量灰尘的户外
0.035
0.04
0.055～0.075
（2）弯曲摩擦阻力
弯曲摩擦阻力是由于胶带硬化和胶带与滚筒轴承摩擦引起的。它与弯曲入口处的张紧力成比例。即为[2]：

式中，—胶带弯曲出口处的张紧力；
—胶带弯曲入口处的张紧力；
—摩擦系数。
3.5 胶带张紧力计算
当计算出每一段的摩擦阻力后，我们可以计算出每一点的张紧力。在我们计算前，我们可以将整个运输路线分成若干切线段和弯曲段，并对每一个连接点进行编号。任意一点的张紧力均可用下式计算[2]：

式中，，—点、点处的胶带张紧力；
—点和点间的摩擦阻力。
驱动滚筒入口和出口处的皮带张紧力可以测得。驱动滚筒上的切向力可以用下式表示：

式中，—驱动滚筒切向力；
—驱动滚筒入口处胶带张紧力；
—驱动滚筒出口处胶带张紧力。
因为不允许胶带在驱动滚筒上滑动，所以必须满足下列条件[2]：

式中，—胶带和驱动滚筒摩擦系数；
—胶带在驱动滚筒上的围包角。
3.6 功率计算
功率主要消耗在克服运行摩擦阻力上。一部分功率用于倾斜输送机的物料提升。驱动滚筒功率可以用下式计算[2]：

因此电动机功率为：

式中，—安全系数；
—传动效率。
4.管状带式输送机结构设计
4.1过渡段长度

图2 过渡段长度
管状带式输送机的过渡段如图2所示。驱动滚筒和从动滚筒之间的胶带是平形的，而在过渡段，胶带的形状由平形转变为管状。过渡段的长度由胶带的最大允许伸长量决定，如果过渡段过短，其两面的附加变形和附加应力都比较大，这会导致胶带损坏。如果过渡段过长，输送装置的封闭输送线路部分就会变短。一般来说，材料为尼龙帆布时其过渡段的长度为25倍的直径，而材料为钢绳芯时，其过渡段长度应为50倍的直径[3]。
4.2 托辊的设计
为了确保滚筒的围包角足够大，平行的托辊必须安装于驱动滚筒与从动滚筒之间