螺杆泵的性能
Screw pump performance
1 排量
A displacement
螺杆泵的理论排量可由下式计算：
Qt=60Ftn m3/h
The theory of displacement screw pump can be calculated by:
Qt = 60Ftn m3 / h
式中：F—泵缸的有效截面积，cm2；t—螺杆螺纹的导程， m；n—主动螺杆的每分钟转数。
螺杆泵的内部泄漏量Qs：
Where: F-pump cylinder effective cross-sectional area, cm2; t-screw thread of the lead, m; n-take the initiative to screw revolutions per minute.
Qs = αp / σm
Qs=αp/σm
式中：p—泵的工作压力；σ—所排送的液体的粘度；α—与 螺杆直径和有效长度有关的系数；m=0.3-0.5。
泵在压送不同粘度的液体时，其排量会发生变化。排量和 粘度的关系可由下式表示：
Q2=Qt-(Qt-Q1)(σ1/σ2)m
式中：Q1—粘度为σ1时的排量；Q2—粘度为σ2时的排量。
Qs = αp / σm
Where: p-pump working pressure; σ-row by sending the viscosity of the liquid; α-and the screw diameter and effective length of the relevant factors; m = 0.3-0.5.
Pump pressure to send a different viscosity of the liquid, its emissions will change. The relationship between the displacement and viscosity by the following formula, said:
Q2 = Qt-(Qt-Q1) (σ1/σ2) m
Formula: Q1-viscosity when σ1 displacement; Q2-displacement when the viscosity is σ2.
2 功率
2 Power
泵的轴功率一般为水功率、摩擦功率和泄漏损失功率这三部分的总和。
The pump shaft power is generally water, power, friction loss of power and leakage power of these three parts combined.
水功率Nc是指单位时间内泵传给液体的能量，也称输出 功率，可用下式计算：
Water power Nc refers to the unit time to pass the liquid inside the pump energy, also known as the output power, can be calculated by:
Nc=PQ×10-3 千瓦
Nc = PQ × 10-3 kilowatt
式中：P—泵的排出压力和吸入压力之差，帕；Q—泵的实 际排量，m3/s。
Where: P-pump discharge pressure and suction pressure difference, Pa; Q-the actual displacement pump, m3 / s.
摩擦功率是指液体粘性阻力产生的摩擦损失，可由下式表示：
Friction power is generated by viscous friction loss of resistance, by the following formula, said:
Nf=Kn1.5D2 σm 千瓦
Nf = Kn1.5D2 σm kW
式中：n—转速；D—主动螺杆的外径；—粘度；K—与螺杆长度有关的系数；m=0.3-0.5。
Where: n-speed; D-active screw diameter; - viscosity; K-factor related to the length with the screw; m = 0.3-0.5.
由上可见，当泵运送的液体粘度不同时，泵的轴功率也将不同。
Is clear from the viscosity of the fluid delivery when the pump is not the same time, the pump shaft power will be different.
泄漏损失是指液体从高压处漏回低压处所造成的功率损失。
Leakage losses is the liquid from the high voltage at low drain back to the premises caused by power loss.
所以，当计算泵的轴功率时，如采用理论排量，则泵的轴功率由下式表示：
N=NfPQt10-3 千瓦
So, when calculating when the pump shaft power, such as the use of theoretical displacement, then the pump shaft power by the following formula, said:
N = NfPQt10-3 Qianwa |
