Centrifugal pump principle

Centrifugal pump cited is based on the principle of centrifugal force design, high-speed rotation of the impeller blades to rotate the water, the water thrown, so as to achieve the purpose of delivery. There are many types of centrifugal pumps, from the use can be divided into civilian and industrial pumps; from the transmission medium can be divided into clear water pumps, impurity pumps, corrosion pumps and so on. Centrifugal is actually the manifestation of the object's inertia, such as water droplets on an umbrella. When the umbrella slowly rotates, the water droplets will follow the umbrella. This is because the friction between the umbrella and the water droplets serves as a centripetal force to the water droplets. But if the umbrella rotates faster, the friction is not enough to make the water drop in circular motion, then the water drop will move away from the umbrella toward the outer edge, just as a rope pulls the stone to make a circular motion. If it is too fast, the rope will Disconnected, the rocks will fly out. This is called Centrifugal. Centrifugal pump main working principle (1) the impeller is driven by the pump shaft rotation, located between the blade fluid doing work, the fluid by the centrifugal force, thrown from the center of the impeller to the periphery. When the fluid reaches the periphery of the impeller, the flow rate is very high. (2) The pump housing collects liquid that is thrown from the vanes and flows in the direction of the gradual enlargement of the volute-shaped passage in the housing to convert the kinetic energy of the fluid into static pressure energy and reduce the energy loss. Therefore, the role of the pump casing is not only to pool the liquid, it is more an energy conversion device. (3) Principle of Liquid Absorption: The high-speed rotation of the impeller forces the liquid in the center of the impeller to be thrown away at a high speed, so that a low pressure is formed in the center of the impeller. Therefore, the liquid in the lower tank is continuously sucked up. Barrage phenomenon: If the centrifugal pump in the shell before the start is full of gas, then start the impeller center gas is thrown there can not be formed in a large enough vacuum, so tank liquid can not be sucked up. This phenomenon is called gas binding. In order to prevent the phenomenon of gas binding, centrifugal pump should be filled with foreign liquid to fill the space before pump starts. This step is called filling pump. In order to prevent the liquid poured into the pump casing due to gravity flow into the lower slot, the pump inlet pipe at the inlet with check valve (bottom valve); if the pump position below the tank surface, then start without irrigation Pump. (4) The outer circumference of the impeller to install the guide wheel, so that the pump liquid energy conversion efficiency. The guide wheel is a fixed, bladed ring located on the periphery of the impeller. The bending direction of the blade is opposite to the bending direction of the impeller blade, the bending angle of the blade matches the direction that the liquid flows out from the impeller, guiding the liquid to change direction smoothly in the passage of the pump casing so as to minimize the energy loss and convert the dynamic pressure energy into High static pressure energy. (5) balance hole on the rear cover to eliminate axial thrust. The pressure of the liquid leaving the periphery of the impeller is already high and some of the liquid will seep to the rear of the impeller rear cover and the liquid inlet at the front of the impeller is under pressure and thus produces an axial thrust pushing the impeller to the pump inlet side. This easily causes the impeller and the pump housing contact wear, severe vibration will occur. The balance hole leaks part of the high-pressure liquid to the low pressure area to reduce the pressure difference around the impeller. But this will also reduce the pump efficiency. (6) shaft seal device to ensure normal and efficient centrifugal pump. Pipeline centrifugal pump in the work of the pump shaft rotation and the shell does not move, during which if the ring gap is not sealed or seal is not good, the outside air will infiltrate the low pressure area of ​​the impeller center, so that the pump flow, efficiency decreased. Serious when the flow is zero - gas tied. In general, a mechanical seal or a packing seal can be used to achieve a seal between the shaft and the shell.