8管道材质走向及弯头汇总.docx

1、8管道材质走向及弯头汇总8Pipeline Material, Orientation, andBends管道材料、走向、及弯头1 INTRODUCTION介绍A major advantage that pneumatic conveying systems have over alternative mechanicalconveying systems is in flexibility in continuous pipeline routing. Pipelinescan run horizontally, and with bends in the pipeline, flows

2、can go verticallyup or vertically down, with little restriction on numbers of bends or distances.Pipelines inclined upwards are not generally recommended and so flow in inclinedpipelines is examined.气力输送系统相对机械输送系统的一个重要的优点是是管道可以方便的布置。水平管道通过弯头，可以垂直向上或向下，对弯头的数量或距离几乎没有限制。一般不建议管道倾斜向上，因此要诊察倾斜管道内的流动。Up to

3、now pressure gradient has been discussed in global terms of pressuredrop available and distance over which a material must be conveyed, with highpressure gradients being required for dense phase conveying. Data is included inthis chapter to show how pressure gradient varies with conveying parameters

4、 forhorizontal and vertical conveying in both dilute and dense phase flows. 截至目前，我们已经讨论了许可压降及物料必须被输送的距离方面的压力梯度的问题，密相输送要求有高的压力梯度。本章中的数据将用来说明压力梯度是怎样随稀相及密相流动中水平和垂直流动常数而变化的。Conveying parameters were introduced in the previous chapter for pipelinebore and conveying distance. In this chapter scaling param

5、eters are presented forother pipeline features including vertical flow. The influence of conveying parameterson pressure drop across bends is considered, for both dilute and densephase flow, and losses are presented in terms of both a pressure drop and anequivalent length. Pipeline material is also

6、considered, with particular reference tothe use of flexible rubber hose.上一章中已经介绍了管道口径和输送距离等输送参数。在这一章将提出其它管道特征，包括垂直流动的换算参数。将研究稀相和密相流动中输送参数对弯头压降的影响，压损用压降和当量长度这两种形式来表达。也将关注管道材料，特别是挠性软管的应用。2 PRESSURE GRADIENT DATA压力梯度数据All the conveying data presented so far has been for total pipeline systems. This isu

7、sually obtained from a test facility comprising a pipeline test loop that generallyincludes horizontal pipeline lengths, a number of bends and possibly an element ofvertical lift. The pressure drop data in the conveying characteristics presented hasbeen for the entire pipeline.迄今为止所有输送数据都是针对全体管道系统的。

8、这通常是从一个试验装置获取，试验装置由一个管道试验回路组成，通常包括水平管长，一些弯头，可能还有一个垂直提升部分。输送特性中的压降数据是针对整个管道的。In order to isolate the effect of any individual element of pipeline, such as astraight section of horizontal or vertical pipeline, or a bend in the pipeline, pressuretappings must be fitted into the pipeline. Some of these

9、issues are consideredin this chapter but are considered in more detail in Chapter 23. 为了隔离管道中任何单个部分的影响，如水平或垂直直管段，或管道弯头，必须从管道取压。其中的一些问题在在本章中讨论，但在第23章中有更详细的论述。2.1 Horizontal Conveying水平输送Typical conveying data for flow in a horizontal section of pipeline is presented inFigure 8.1. The data is for bari

10、te, which is often used as a drilling mud powder.This material has a particle density of about 260 lb/ft3 but despite this it will beseen that the material could be conveyed at solids loading ratios in excess of 100and at low velocity. For drilling purposes it is used as a very fine powder and sohas

11、 very good air retention properties in this form. As a consequence of the airretention properties the material will convey in dense phase flow.管道水平段流动的典型输送数据显示在图8.1中。这些是重晶石的数据，重晶石通常被用作钻井泥浆粉末。 这种物料的颗粒密度约为260 lb/ft3（注：约4165kg/m3），除此之外，还可看到，物料能超过100的混合比低速输送。用在钻井上，是一种非常细的粉末，因此以这种形式它具有良好的。由于其存气性，它能以密相来输送

12、。Figure 8.1 Pressure gradient in horizontal flow for barite in 2 inch bore line.重晶石在2英寸口径管道中的水平流动压力梯度。The data in Figure 8.1 is presented in exactly the same form as the conveyingcharacteristics, with material flow rate in Ib/h plotted against free air flow ratein fVVmin. The family of curves plotte

13、d is now of pressure gradient in lbf/in2 per100 ft length of pipeline rather than a pressure drop for the total pipeline. Lines ofconstant solids loading ratio are also included as these are simply straight linesthrough the origin as before. The juxtaposition of these two sets of curves on theone pl

14、ot is particularly useful for illustrating once again the problem of maintainingflow in dense phase with increase in conveying distance.图8.1中的数据与输送特性具有完全一样的形式，图中横坐标为自由空气流量（ft3/min），纵坐标为物料流量（lb/h）。现在用压力梯度（lbf/in2每100 ft）的一组曲线来替代总管线的压降。恒定混合比线也列入其中，像以前一样它们是通过原点的直线。这两组曲线并列显示在一个图上，对再次说明随输送距离增加维持密相流动的难题特别

15、有用。2.1.1 Long Distance Conveying长距离输送As expected, it will be seen that as the solids loading ratio increases, the pressuregradient increases. At a solid loading ratio of about 100 the pressure gradient isapproximately 10 lbf/in2 per 100 ft length of pipeline. With a limit on air supplypressure becau

16、se of air expansion problems, and the consequent need to step thepipeline, the scope for long distance dense phase flow is strictly limited. This doesnot take account of the additional pressure drop due to bends and sections of verticallyupward pipeline that might need to be included either. 正如预期的那样

17、，可以看到，随着混合比的增加，压力梯度也增加。混合比约100时的压力梯度大约为10 lbf/in2每100 ft长度的管道。因为空气膨胀的问题对供气压力有一定的限制，而且需要对管道扩管，长距离密相输送的范围受到了严格限制。这并不没有考虑到可能需要列入的由于弯头和垂直向上管段生产的附加压降。For longer distance conveying there must be a compromise and this is toconvey at a lower value of solids loading ratio where the pressure gradient islower.

18、 In Figure 7.2Id, magnesium sulfate conveyed over a distance of 2500 ft ispresented and the maximum value of solids loading ratio, with a conveying linepressure drop of 30 lbf/in2, is only about 1 /2. 对于长距离输送，必须要折衷考虑，压力梯度更低时的输送混合比也就更低了。在图7.21d中 ，输送硫酸镁的距离为2500 ft，输送线压降为30 lbf/in2 ，而最大混合比只有约1 /2。3 VER

19、TICAL CONVEYING垂直输送Apart from the difficulty of finding a suitable wall or structure on which to mounta vertical pipeline for testing purposes, a test loop needs to be used, unless twoconveying systems are available, one conveying to the other. The former was usedfor the test work reported here 1. A

20、n advantage of this method is that the pipelinemust go down as well as up and so data can be obtained for both sections of pipelinein every test run. 除了难以找到合适的墙壁或结构来支撑进行试验的垂直管道之外，需要使用一个试验回路，除非有两个输送系统，一个输送到另一个。用于试验工作所使用的模型回报于此 1 。这种方法的一个优点是，管道必须下降和上升同样的高度，因此在每次测试运行中可以同时测得两段管道中的数据。A sketch of the test

21、 pipeline is given in Figure 8.2 together with dimensionaldetails. A high pressure top discharge blow tank was used to feed material into thepipeline. The layout of the test facility was such that the material was conveyedvertically down first and then vertically up. The fall and rise elements of th

22、e pipelinewere both 53 ft long. The total pipeline length was about 185 ft. Two pipelineswere available; one of two inch and another of three inch nominal bore, bothfollowing an identical routing.图8.2给出了试验管道的示意图与三维细节。采用一个高压上引式发送罐来供料。试验设施的布局是这样的，物料先是垂直向下输送，然后垂直上升。下降和上升管道均为53 ft长。管道总长度约185 ft。有两条管道，一个

23、的名义直径为两个英寸，另一个为两个英寸，它们的走向是一样的。Typical conveying characteristics for the total pipeline system are presentedin Figure 8.3 2. These are for barite conveyed through the three inch bore pipeline.Barite can be conveyed in dense phase, as was illustrated in Figure 8.1 and soconveying with air supply press

24、ures up to 30 lbf/in2 was possible and solids loadingratios of well over 100 were achieved.图8.3介绍了总的管道系统典型的输送特性 2 。这些都是通过三个英寸口径管道输送重晶石。如图8.1所示，重晶石可以密相来输送，因此当输送空气供应压力高达30 lbf/in2时，混合比远远超过100。Figure 8.2 Details of test pipeline试验管道详图。Figure 8.3 Conveying characteristics forbarite in figure 8.2 pipelin

25、e of 3 inch bore.图8.2的3英寸口径管道输送重晶石的输送特性。Once again this illustrates the conveying potential of relatively small borepipelines in that material flow rates of over 100,000 Ib/h were achieved. For thetotal pipeline the form of the conveying characteristics is little different from thatfor other pipelin

26、e systems presented in earlier chapters. 这再次说明了相对较小口径管道输送这种物料的输送潜力能超过100,000 Ib/h（注：约45t/h）。对于总的管道，输送特性的形式和前面几章中的其他管道系统没有什么不同。In order to obtain pressure gradient data for the two test sections there were15 pressure tappings (seven along the down section and eight along the up section).The first and

27、 last tappings at each section were placed about five feet fromthe bends in order to ensure that any upstream or downstream effects would haveminimum influence on the pressure readings. At each location a ring of four tappingswas used and all four were coupled to a common point. 为了获得这两个测试段的压力梯度数据，共有

28、15个取压点（七个在下降段，八个在上升段）。每个管段上的第一次和最后一个取压点都放在离弯头约五英尺远处，以确保任何上游或下游对压力读数的影响最小。在每个地点都有一圈四个取压口，这四个都是相对同一点对称布置。Results from two tests carried out with a fine grade of pulverized fuel ash(fly ash) in the two inch bore pipeline are presented in Figure 8.4 2, 3. The horizontalaxis represents the length of pipe

29、line (see Figure 8.2) from the bend inwhich the flow is horizontal to vertically down (bend number 4), to the bend inwhich the flow is vertically up to horizontal (bend number 7).在两英寸口径管道中对细粉级粉煤灰(飞灰)进行的两次试验的结果显示在图8.4 2, 3中 。横轴代表从水平转为垂直流动的弯头（弯头4）开始的管道的长度（见图8.2 ）到从垂直转为水平流动的弯头（弯头7）为止 。The first section

30、, therefore, represents the flow vertically down, along whichthere were seven pressure tapping locations, and the second section represents theflow vertically up, along which there were eight pressure tapping locations. Thevertical axis represents the pressure of the conveying air.因此，第一部分代表垂直向下的流动，在

31、这一段上有七个取压点，第二部分代表垂直上升的流动，在这一段上有八个取压点。垂直轴表示的是输送空气压力。The solid lines drawn represent the linearized dependence, from the measuredvalues of pressure, while the dotted lines represent an approximate developmentof the pressure in the region where the pressure was not measured.实线代表压力测量值的线性关系，而虚线代表没有测量点的区域

32、的大致压力。Figure 8.4 Typical pressure gradient results obtained with pulverized fuel ash.输送粉煤灰的典型的压力梯度。It will be noticed that in one case the pressure gradient in the verticallydown section was negative, while in the other it was positive. In the vertically upflow the pressure gradient was negative in each case, but there was a significantdifference between the two tests. The influence that conveying conditions canhave on the values of pressure gradie