管状带式输送机的参数计算和结构设计.docx

1、管状带式输送机的参数计算和结构设计中文3150字英文原文Parameters Calculation and Structure Design of Pipe Belt ConveyerZaimei Zhang1, Fang Zhou2, Jianheng Ji21School of Mechanical Engineering, University ofJinan, Jinan 250022, Shandong Province,China2Departments ofInformation Engineering, Shandong Water Vocational College, R

2、izhao 276826,Shandong Province, ChinaAbstract: 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 o

3、f conventional belt conveyor s. The parameters such as throughput, belt speed, belt width, resistance, tension in belt and power are described. The length of transitionsection is analyzed because it is important to the belt life. Hexagon supporting rollers and tipping device are necessary parts ofpi

4、pe belt conveyor. The structures of them are also discussed.keywords: Pipe Belt Conveyor, Transition Section,Hexagon Supporting Rollers, Tipping Device 1. IntroductionPipe belt conveyor is a new type of special belt conveyor which developed from the conventional belt conveyor. In this conveyor, flat

5、 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 19791 .After that, it was rapidly dev

6、eloped 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 conveyorFigurel 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

7、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 h

8、ead. 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 conveyor1.(1) Unpolluted conveyanceIn pipe belt conveyor, material doesnt come out and isnt influenced by environment because the bel

9、t 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 conveyanceObliquity can reach about 18 in the conventional belt conveyor. But in pipe belt conveyor, material is enveloped in pipe and friction

10、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 convenientBelt can be tubular in return of pipe belt conveyor and material can be conveyed in

11、the reverse direction by special device such as special feeder and tipping device.(4) Conveyor bed is narrowIn 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 .

12、Main parameters calculation of pipe belt conveyorMain parameters in pipe belt conveyor are throughput, belt width, belt speed and power. But production throughput is always given.3.1 Calculation throughputThroughput of conveyor can be fonnulated as follows2:Where is belt speed, is the pipe area, is

13、density of material conveyed and is coefficient of material filling, = 0.440.8. 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

14、.44.3.2 Belt speedBelt 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 invest

15、ment in belt and power consumption. Belt speed usually used is 25m/s3.3.3 Belt widthBelt width can be calculated according throughput. The belt diameter can be expressed2: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

16、 between belt width and pipe diameter is as follow:3.4 Running resistance calculationThe 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 ca

17、lculated 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 tangentResistance in belt with load2:Resistance in belt without load:Where is res

18、istance 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 convey

19、ance, 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 curvatureResistance in curvature is caused by belt ossification and friction in roller bearings. It is proportional to t

20、he tension at curvature entrance. That is2 :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 beltAfter resistance in each section has been calculated, we can calculate the tension at every point.

21、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 followed2:Where and are tension in belt at point and point , is resistance between point and point . The tension at driving roller entrance a

22、nd 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

23、 be satisfied because the belt do not permitted to slide on driving roller2.Where is the coefficient of friction between the belt and driving roller, is angle of the belt enveloping on the roller.3.6 Power calculationPower is mainly consumed in overcoming running resistance. And some power is used i

24、n elevating material in sloping conveyor. Power on driving roller shaft can be calculated by the follower expression2:So the motor power is:Where is a factor of safety and is transmission device efficiency.4 Structure design of pipe belt conveyor4.1 The length of transition sectionFigure 2 Length of

25、 transition sectionTransition 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, addit

26、ional 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 di

27、ameters in wire rope belt3.4.2 Design of supporting rollersParallel 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 fla

28、t 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

29、spacing is about 300500mm4.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

30、on the same side of supporting board. Generally speaking, the adjacent rollers spacing should not exceed the belt thickness, usually 48mm. 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 side

31、s 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 b

32、oardFigure 4. Rollers on two side of suppporting boardRigidity 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 spacin