The working principle of centrifugal pump
first, the principle of centrifugal pumps
1, the principle of centrifugal pumps
of impeller of a centrifugal pump installed inside the pump casing 2, and tighten the pump shaft 3, shaft driven directly by the motor. Center the pump casing is a liquid inhalation 4 and 5 connection of suction tube. Liquid through the valve 6 and at the end of the suction pipe into the pump. Liquid line exit 8 on the pump casing and discharge pipe 9 connections.
in the pump before starting, fill the pump casing is transmission fluid; starts, after the impeller shaft high speed rotation, liquids must also be between the blade turning. Under the action of centrifugal force, the liquid was thrown to the outer edge and gain energy from the impeller Center, leaving the outside edge of the impeller with high speed into the volute pump casing. In the volute, due to the flow of the liquid gradually slowed down, and some of the kinetic energy into pressure, and finally at high pressure into the discharge pipe, sending it to the needed place. Liquid flow from the center of the impeller when the outer edge, in the Center to form a certain vacuum impeller, since tank pressure above the liquid surface is greater than the pump inlet pressure, the liquid is continuously pressed into the impeller. Obviously, as long as the constantly rotating impeller, the liquid will continue to be inhalation and discharged.
Figure 2-1: centrifugal pump installation diagram
gas when the pump has air in the shell, the air density is much less than the density of the liquid and cause less centrifugal force. Thus, tank liquid level above the pump suction inlet pressure is not enough to press the tank liquids into pump, centrifugal pump not self-priming capacity, make it impossible for centrifugal pump liquid transport, this phenomenon is known as "tied".
to make the pump filled with liquid, usually along the bottom of suction tube filter bottom valve, the valve at the end of valve, filter damaged's role is to prevent solids from entering the pump impeller or interfere with the normal operation of the pump.
II, main parts centrifugal pump
the main parts of centrifugal pump impeller, pump housing and shaft seal.
impeller the impeller is the role of the prime mover's mechanical energy directly to the liquid to increase static pressure and kinetic energy of the liquid (mainly increase static pressure). General 6~12
impeller bent blade.
impeller has open, semi-closed and closed three, as shown in Figure 2-2.
Figure 2-2 centrifugal pump of impeller diagrams
open type impeller in leaves sides no cover Board, manufacturing simple, and cleaning convenient, applies Yu conveying contains more large suspended real of material, efficiency lower, conveying of liquid pressure not high; half closed type impeller in sucking entrance side no cover Board, and in another side has cover Board, applies Yu conveying easy precipitation or contains particles of material, efficiency also lower; closed type impeller in impeller in leaves sides has before and after cover Board High efficiency, suitable for transporting cleaning liquid does not contain impurities. General centrifugal pump impeller for this class.
impeller is single suction and double suction suction.
pump impeller closed shells are used to a certain amount of space, so that the impeller suction and pressure the liquid. Pump volute-shaped, so it is also called the volute. Due to flow path cross-sectional area gradually expanded, it gradually reduces from around the impeller out of high speed liquid flow, some kinetic energy is efficiently converted to static pressure. Pump case brings together not only by the impeller out of the liquid, but it is also an energy conversion device.
3, shaft seal
sealing system's role is to prevent the liquid in the pump casing leakage along an axis or an external air leakage into the pump housing.
packing seal and mechanical seal shaft seal device commonly used in two ways.
packing generally coated with oil or graphite asbestos rope. Mechanical seal is mounted on the shaft of the main ring with fixed between the stationary ring on the pump casing for relative motion reaches the end face seal ends.