螺桿泵的性能
Screw pump performance
1 排量
A displacement
螺桿泵的理論排量可由下式計(jì)算：
Qt=60Ftn m3/h
The theory of displacement screw pump can be calculated by:
Qt = 60Ftn m3 / h
式中：F—泵缸的有效截面積，cm2；t—螺桿螺紋的導(dǎo)程， m；n—主動螺桿的每分鐘轉(zhuǎn)數(shù)。
螺桿泵的內(nèi)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—泵的工作壓力；σ—所排送的液體的粘度；α—與 螺桿直徑和有效長度有關(guān)的系數(shù)；m=0.3-0.5。
泵在壓送不同粘度的液體時(shí)，其排量會發(fā)生變化。排量和 粘度的關(guān)系可由下式表示：
Q2=Qt-(Qt-Q1)(σ1/σ2)m
式中：Q1—粘度為σ1時(shí)的排量；Q2—粘度為σ2時(shí)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
泵的軸功率一般為水功率、摩擦功率和泄漏損失功率這三部分的總和。
The pump shaft power is generally water, power, friction loss of power and leakage power of these three parts combined.
水功率Nc是指單位時(shí)間內(nèi)泵傳給液體的能量，也稱輸出 功率，可用下式計(jì)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—泵的排出壓力和吸入壓力之差，帕；Q—泵的實(shí) 際排量，m3/s。
Where: P-pump discharge pressure and suction pressure difference, Pa; Q-the actual displacement pump, m3 / s.
摩擦功率是指液體粘性阻力產(chǎn)生的摩擦損失，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—轉(zhuǎn)速；D—主動螺桿的外徑；—粘度；K—與螺桿長度有關(guān)的系數(shù)；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.
由上可見，當(dāng)泵運(yùn)送的液體粘度不同時(shí)，泵的軸功率也將不同。
Is clear from the viscosity of the fluid delivery when the pump is not the same time, the pump shaft power will be different.
泄漏損失是指液體從高壓處漏回低壓處所造成的功率損失。
Leakage losses is the liquid from the high voltage at low drain back to the premises caused by power loss.
所以，當(dāng)計(jì)算泵的軸功率時(shí)，如采用理論排量，則泵的軸功率由下式表示：
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 |
