渣浆泵特性曲线的用途

离心泵的实际特性曲线表明，泵在恒定转速下工作时,对应于泵的每一个流量Q必定相应有一个确定的扬程H、功率P、效率η和汽蚀余量[NPSHr]。在实际中,每条曲线都有其作用。
    (1)H-Q曲线是选择和操作使用泵的主要依据。因各种泵的结构型式不同,所以H-Q曲线有“陡降”、“平坦”及“驼峰”等形状。具有平坦形H-Q曲线的离心泵的特点是:在流量变化较大时,扬程H变化不大;具有陡降H-Q特性的离心泵正好相反，当扬程变化较大时，流量Q变化不大;具有驼峰形H-Q特性的泵，在某一流量范围(小于峰值流量)内，容易产生不稳定工况。用户可根据工作要求来选择具有不同特性的离心泵。

对具有平坦或陡降H-Q特性的离心泵，流量Q增大，扬程H下降，反之亦然。因此，在离心泵操作中，可以用减小或增大扬程H来调节流量Q。生产中常采用调节泵出口阀门，改变管路阻力损失，进而使泵提供的扬程H发生变化，达到调节流量的的。

(2)P-Q曲线是合理选择原动机功率和正常启动的依据。通常应按所需流量变化范围中的最大功率，再加上适当的安全余量来确定原动机的功率。应确保泵在耗功最小的条件下启动，以降低启动电流保护电动机。一般当Q=0时，离心泵的功率最小，因此，启动泵时，应关闭出口调节阀门，待泵正常运转后，再调节到所需流量。渣浆泵

(3)η- Q曲线是确定泵工作经济性的依据。离心泵实际运行效率是判断离心泵运行是否经济的主要指标,离心泵的工作点如果对应的效率较高，即能够满足经济性要求。工程上将泵最高效率点称为额定点，与该点相对应的工况称为额定工况(即额定流量、额定扬程、额定功率),它一般就是泵的设计工况。离心泵的设计流量按照最高效率点确定,因此，当离心泵的实际流量偏离设计流量较多时，离心泵的效率下降就较多。在实际工作中，要保证离心泵的工作点能够接近离心泵效率最高点，泵应尽量在高效率区域工作。为了扩大泵的使用范围,通常规定:对应于最高效率点以下7%的工况范围为高效工作区，有些离心泵样本上只给出高效工作区内的各特性曲线。
    (4)NPSHr-Q曲线是检查泵是否发生汽蚀的依据。泵的安装高度和入口阻力损失等应全面考虑，防止泵发生汽蚀。、

Application of characteristic curve of slurry pump

The actual characteristic curve of centrifugal pump shows that when the pump works at constant speed, each flow Q corresponding to the pump must have a certain head h, power P, efficiency η and NPSHr. In practice, each curve has its own function.

(1) H-Q curve is the main basis for selecting and operating pumps. Because of the different structure types of pumps, H-Q curve has "steep drop", "flat" and "Hump" shapes. The characteristics of the centrifugal pump with flat H-Q curve are as follows: when the flow changes greatly, the head h does not change much; the centrifugal pump with steep drop H-Q characteristics is just the opposite, when the head changes greatly, the flow Q does not change much; the pump with hump H-Q characteristics is easy to produce unstable conditions in a certain flow range (less than the peak flow). The user can choose the centrifugal pump with different characteristics according to the working requirements.

For the centrifugal pump with flat or steep drop H-Q characteristics, flow Q increases, head h decreases, and vice versa. Therefore, in the operation of centrifugal pump, the flow Q can be adjusted by reducing or increasing the head H. In production, the outlet valve of the pump is often adjusted to change the resistance loss of the pipeline, so that the head h provided by the pump changes to adjust the flow.

(2) The P-Q curve is the basis for the reasonable selection of prime mover power and normal start-up. Generally, the power of the prime mover should be determined according to the maximum power in the range of the required flow change and the appropriate safety margin. It shall be ensured that the pump is started under the condition of minimum power consumption to reduce the starting current to protect the motor. Generally, when q = 0, the power of centrifugal pump is the minimum. Therefore, when starting the pump, the outlet regulating valve shall be closed, and after the pump operates normally, the required flow shall be adjusted. Slurry pump

(3) η - Q curve is the basis to determine the economic performance of pump. The actual operation efficiency of centrifugal pump is the main index to judge whether the operation of centrifugal pump is economical. If the corresponding efficiency of the working point of centrifugal pump is high, it can meet the economic requirements. In engineering, the highest efficiency point of pump is called rated point, and the corresponding working condition is called rated working condition (i.e. rated flow, rated head and rated power), which is generally the design working condition of pump. The design flow of centrifugal pump is determined according to the highest efficiency point. Therefore, when the actual flow of centrifugal pump deviates from the design flow more, the efficiency of centrifugal pump will drop more. In practical work, to ensure that the working point of centrifugal pump can be close to the highest efficiency point, the pump should work in the high efficiency area as much as possible. In order to expand the scope of use of the pump, it is generally stipulated that the operating range corresponding to 7% below the highest efficiency point is the high efficiency working area, and some centrifugal pump samples only give the characteristic curves in the high efficiency working area.

(4) Npshr-q curve is the basis of checking whether the pump has cavitation. The installation height and inlet resistance loss of the pump shall be fully considered to prevent cavitation of the pump.