渣浆泵在交汇管路上工作的装置特性

在石油生产中，矿区中各转油站的原油汇集后输往油库的管路属于交汇管路。

交汇管路与两泵并联不同，设两泵分别从A、B两油罐吸入油品,并经过两条相当长的管路1、2把油品送到汇合点O,然后经一条管路3把油品送到储油处C点，如图1-49所示。这种管路系统的特点是:在整个系统工作时,尽管两台泵性能不同,管1和管2的阻力、静扬程也不同,但油品从泵I和泵II输送到O点后的剩余能头必须相等。

(1) 图解法。

交汇管路的工作状况可以用性能曲线图来分析。首先作出泵 I的性能曲线(H-Q)l和管路1的特性(h-Q)(包括泵I的吸入管和排出的总管路特性) .从泵I性能曲线的纵坐标上减去同流量下管1的管路特生的纵坐标,即得出在不同流量下泵I输送油品到O点的剩余扬程曲线l。它表示从泵1给出的能头中减去管1的阻力损失等能头后还剩余的能头，此剩余能头是用来克服管3的阻力损失及将油品输送到C处所需克服的位高能头。按同样的方法，可以作出泵lI输送油品至0点后的剩余扬程曲线lI。曲线I、lI就相当于装在0点处另两泵的性能曲线。把曲线I和Il并联相加,得并联剩余扬程曲线lll,它表示0点处油品在不同流量下的能头大小。
    作管3的管路特性与曲线lII相交于M点,则M点为工作点，该点对应的流量Qm就是管3中的流量Q3,必等于管1和管2中的流量和。M点的能头为管1和管2汇合后的剩余能头，也就是用来克服管3中阻力和位高差所需要的能头。
    为确定泵I和泵lI的工作点，过M点作水平线与曲线1和Il相交于点1和2.过点I和点2作垂线,分别交泵1性能曲线于M点，交菜口性能曲线于M,点。M点对应的流量Q就是管1中的流量，M2点对应的流量:就是管2中的流量。M点的纵坐标即泵l的工作扬程，M2点的纵坐标即泵II的工作扬程。

由此可见，只要掌握能量供应和能量消耗的关系，就能在任何复杂工况下确定每台泵的工作流量和工作扬程，即工作点。
(2)解析法。

分别由两台渣浆泵实测或泵特性曲线上取点得到几组扬程、流量数据，用最小二乘法回归得到泵的特性方程分别为:

泵l的特性方程   H1=a1-b1Q1

泵ll的特性方程   H2=a2-b2Q2

系数a1、b1、a2、b2可由式(1-69)计算得到。

管路1的特性方程为：  h1=（z-z1）+k1Q1

管路2的特性方程为：   h2=（z-z2）+k2Q2

管路3的特性方程为：   h3=（z-z3）+k3Q3

Device characteristics of slurry pump working on the intersection pipeline
In oil production, the pipelines that the crude oil from each oil transfer station in the mining area is collected and then transported to the oil depot belong to the intersection pipelines.
Different from the parallel connection of two pumps, two pumps are set to draw oil from oil tanks a and B respectively, and then send the oil to the confluence point O through two rather long pipelines 1 and 2, and then send the oil to the oil storage point C through one pipeline 3, as shown in Figure 1-49. The characteristics of this pipeline system are as follows: during the operation of the whole system, although the performance of the two pumps is different, the resistance and static head of pipe 1 and pipe 2 are also different, the residual energy head after the oil is transported from pump I and pump II to point O must be equal.
(1) Graphic method.
The working condition of the intersection pipeline can be analyzed by performance curve. Firstly, the performance curve (H-Q) l of pump I and the characteristics (H-Q) of pipeline 1 (including the characteristics of suction pipe and discharge pipe of pump I) are made. The vertical coordinates of the special pipeline of pipeline 1 under the same flow are subtracted from the vertical coordinates of the performance curve of pump I, and the residual lift curve l of the oil delivered by pump I to o point under different flow is obtained. It represents the remaining energy head after subtracting the resistance loss and other energy heads of tube 1 from the energy head given by pump 1. The remaining energy head is used to overcome the resistance loss of tube 3 and the potential energy head to be overcome when delivering oil to place C. According to the same method, the remaining lift curve (LI) after the pump Li delivers the oil to the zero point can be made. Curve I and Li are equivalent to the performance curve of the other two pumps installed at point 0. By adding curve I and IL in parallel, the curve LLL of the remaining head in parallel is obtained, which represents the energy head size of the oil at point 0 under different flow rates.
If the pipeline characteristic of work pipe 3 intersects with the curve LII at point m, then point m is the work point, and the corresponding flow QM at this point is the flow Q3 in pipe 3, which must be equal to the flow sum of pipe 1 and pipe 2. The energy head at point m is the residual energy head after the combination of tube 1 and tube 2, which is the energy head needed to overcome the resistance and height difference in tube 3.
In order to determine the working points of pump I and pump Li, the horizontal line passing through point m intersects with curve 1 and IL at points 1 and 2. The vertical line passing through point I and point 2 intersects with pump 1 performance curve at point m, and the performance curve passing through point m, respectively. The flow Q corresponding to point m is the flow in tube 1, and the flow corresponding to point M2 is the flow in tube 2. The ordinate of point m is the working head of pump L, and the ordinate of point M2 is the working head of pump II.
Thus, as long as we master the relationship between energy supply and energy consumption, we can determine the working flow and head of each pump under any complex working condition, that is, the working point.
(2) Analytical method.
Several groups of head and flow data are obtained from the actual measurement of two slurry pumps or the points on the pump characteristic curve. The characteristic equations of the pumps are obtained by least square regression
Characteristic equation of pump l H1 = a1-b1q1
Characteristic equation of pump ll h2 = a2-b2q2
The coefficients A1, B1, A2 and B2 can be calculated by formula (1-69).
The characteristic equation of pipeline 1 is: H1 = (z-z1) + k1q1
The characteristic equation of pipeline 2 is: h2 = (z-z2) + k2q2
The characteristic equation of pipeline 3 is: H3 = (z-z3) + k3q3