Proper selection of twin screw pump to start what data?

Twin screw pump is the use of screw rotation to suction liquid. The middle of the screw for the active screw, driven by the prime mover rotation, the screw on both sides of the driven screw, with the active screw for reverse rotation. The main, driven screw thread are double-headed thread. Due to the mutual engagement of the screws and the close cooperation of the screw with the inner wall of the liner, one or more sealed spaces are separated between the suction and discharge of the pump. As the screw is rotated and engaged, these sealed spaces are constantly formed at the suction side of the pump, sealing the liquid in the suction chamber therein and continuously displacing in the axial direction of the screw from the suction chamber to the discharge end to be closed in the respective spaces Continued discharge of liquid, like a nut in the screw rotation is constantly moving forward, as the case, which is the basic working principle of the screw pump. As a positive displacement pump, mainly with the flow, speed, pressure and viscosity are related: Flow Q of the factors: the main speed N, the pressure P and the viscosity of the media V. Influencing factors of rotation speed N: During the operation of the screw pump, a sealed chamber is formed between the two screws and the bushing. Each time the screw rotates one time, a sealed chamber is removed from the inlet to the outlet, that is, the volume of liquid in a sealed chamber is discharged. Ideally, there is no leak inside the pump, so the pump flow is proportional to the speed. Pressure factors: pump actual work process, its internal existence of leakage, also known as slip. Because there is a certain gap in the sealed chamber of the pump, there is a pressure difference ΔP before and after the sealed chamber. Therefore, there is a part of liquid backflow, that is, there is a leak, and the amount of leakage is expressed by △ Q, then Q = Qth- △ Q. Before and after the sealed chamber, the pressure difference △ P increased, the amount of leakage △ Q gradually increased. The impact varies depending on the type and structure. Factors Affecting Viscosity: Clear water and viscous paste are leaked out of the funnel-type container in the same volume. Clearly, water leaks faster than paste. Similarly, for the twin-screw pump, viscous fluid smaller than the viscosity of liquid leakage is small, the amount of leakage and medium viscosity has a certain proportion.