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渣漿泵流量揚程的工作范圍

(1)泵的極限工作范圍是指圖1- 39中由曲線1.2.3.6圍成的區域EFGH.曲線1表示標準葉輪直徑D2時的H-Q曲線，曲線2表示最小葉輪直徑D.時的H一Q曲線，曲線3表示由最小連續流量[Qm.]確定出的相似拋物線.曲線6表示由最大極限流C[Qm確定出的相似拋物線。泵可以在極限工作范圍內連續運行。最小連續流量[Qmin]是指泵在不超過標準規定的噪聲、振動、溫升下能夠正常運行時的最小流量,一般由泵制造商提供。當泵的流量增加時，必需的汽蝕余量NPSH,也隨之上升,出現汽蝕的可能性增加，同時軸功率上升很快，存在過載的可能。因此，一般規定最大連續流量[Qmx]小于在最高效率點流量QN的125%~1 35 %。

(2)泵的高效工作范圍是指圖1- 39中由A.B.C.D所圍成的扇形陰影區域，泵在該區域內的任意一點工作均認為是合適的。A、B兩點為標準葉輪直徑D,時H-Q曲線上比最高效率點N效率7-低a7的等效率工況點。過A.B兩點可以作出兩條等效率切割拋物線4和5，并交最小葉輪直徑D..時的H-Q曲線于C.D兩點。關于單級渣漿泵、多級離心水泵、石油化工離心泵的效率,應符合GB/T 13007 2011 和GB 19762- 2007 的規定，一般規定泵工作時的效率與最高效率之間的差值4n應不大于7%。選泵時,運行工作點應落在此高效工作區內。一般離心泵樣本給出的特性曲線就是這種切割高效工作區的四邊形。

Working range of flow head of slurry pump

(1) The limit working range of the pump refers to the efgh. Curve 1 in the area enclosed by curve 1.2.3.6 in Figure 1-39 represents the H-Q curve of standard impeller diameter D2, curve 2 represents the H-Q curve of minimum impeller diameter D., curve 3 represents the similar parabola determined by the minimum continuous flow [QM.]. Curve 6 represents the similar parabola determined by the maximum limit flow C [QM.]. The pump can operate continuously within the limit working range. The minimum continuous flow rate [qmin] refers to the minimum flow rate when the pump is able to operate normally under the noise, vibration and temperature rise specified in the standard, which is generally provided by the pump manufacturer. When the flow of the pump increases, the necessary NPSH will also rise, and the possibility of cavitation will increase. At the same time, the shaft power will rise rapidly, and there is the possibility of overload. Therefore, it is generally specified that the maximum continuous flow [qmx] is less than 125% ~ 135% of the flow QN at the highest efficiency point.

(2) The efficient working range of the pump refers to the sector shadow area enclosed by a.b.c.d in Fig. 1-39. It is considered appropriate for the pump to work at any point in this area. A. Point B is the constant efficiency operating point with the standard impeller diameter D, which is 7-7 lower than the highest efficiency point n on the H-Q curve. Two equal efficiency cutting parabolas 4 and 5 can be made through point A.B, and the H-Q curve at the minimum impeller diameter D.. Can be intersected at point C.D. The efficiency of single-stage slurry pump, multi-stage centrifugal pump and petrochemical centrifugal pump shall comply with the provisions of GB / T 13007 2011 and GB 19762-2007. Generally, it is specified that the difference between the efficiency when the pump is working and the highest efficiency shall not be greater than 7%. During pump selection, the operating point shall be located in this efficient working area. Generally, the characteristic curve given by centrifugal pump sample is the quadrilateral of this cutting efficient working area.