Pump basic principle

First, the basic principles of the pump 1, the definition and classification of the pump (1), the concept: the pump is the prime mover (common prime mover diesel engines, gasoline engines and other internal combustion engines, motors, fire engines, Diesel or petrol engine) to a machine that pumps liquid energy. The prime mover drives the impeller to rotate through the pump shaft to work on the liquid to increase its energy so that the required amount of liquid is pumped by the sump to the required altitude or required pressure. Pump suction principle: The figure below shows a simple pump unit. The prime mover drives the impeller to rotate, drawing water into the pump from A and delivering to B. Pump plays a leading role in the impeller, the impeller blades forced liquid rotation, liquid centrifugal force thrown to the surrounding. This situation is like a rotating umbrella, the umbrella drops on the water around the same reason thrown. After the liquid in the pump is thrown out, the new liquid enters the pump at atmospheric pressure. So continuously from A to B at the water supply. Before starting the pump, it should be filled with water. If not filled with water, the impeller can only rotate the air, because the mass of the air unit volume is very small, the resulting centrifugal force is very small, unable to discharge the air in the pump and the drain, creating a vacuum in the pump, the water Can not suck up Pump at the end of the valve is used for irrigation, pump outlet side of the control valve is used to regulate the flow. Fire pump before the car can be filled with water, encountered must absorb water from the natural source, you need to start the pilot, the pump chamber and suction pipe air discharge, the liquid at atmospheric pressure into the pump, so the pump is also Continuous water can be absorbed. (2), the type of pump Pump can be divided into vane pumps, positive displacement pumps and other types of pumps three categories. ⑴, vane pump: also known as power pump, this pump is continuously applied to the liquid energy, such as centrifugal pumps, mixed flow pump, axial flow pump. ⑵, positive displacement pump: In this pump, by closing and filled with the cyclical changes in liquid volume, discontinuously to the liquid to exert energy, such as piston pump, gear pump, screw pump. ⑶, other types of pumps: The role of these pumps vary in principle, such as jet pumps, water hammer pumps, electromagnetic pumps and so on. The detailed pump classification is shown in Table 1-1. 2, the main flow of vane pump parts and structure of the structure: (1), vane pump overcurrent components have a suction chamber, impeller, pressure chamber (including vanes). Pump suction chamber is located in front of the impeller, its role is to lead the liquid to the impeller, a straight cone, pipe-shaped and spiral three forms. Pressurized water chamber is located outside the impeller, its role is to collect the liquid from the impeller out into the discharge tube. Pressure water room mainly spiral pressure chamber (volute), guide vane and space guide vane in three forms. The impeller is the pump's most important working element, is the heart of the over-current components. Impeller by the cover and the middle of the leaves. According to the liquid from the impeller out of the different directions, the impeller is divided into centrifugal (radial flow), Francis (oblique flow) and axial flow of three types. Centrifugal impeller - the direction of the fluid out of the impeller perpendicular to the axis; Francis impeller - the direction of liquid flow out of the impeller is inclined to the axis; pump classification vane pump centrifugal pump single stage (single suction, double suction, self-suction, Multistage (segmented, volute type) mixed flow pump scroll pump vane (fixed vane, adjustable vane) Axial flow pump fixed vane, adjustable vane vortex pump Single, multistage, self-priming, non-priming Positive displacement reciprocating pump (piston type, piston type) Double acting type steam cylinder (single cylinder, multi cylinder) Electric reciprocating type - Single acting, double acting ); Gear type (with the meshing, external meshing); circulating piston (internal circulation, external circulation); vane; cam; axial piston; radial piston type other types of jet pumps, gas Yang Water pumps, water hammer pumps, electromagnetic pumps, water pumps, etc. Axial flow impeller - Liquid flows out of the impeller in a direction parallel to the axis. (2) Structure of vane pump Structure of vane pump is divided into the following categories: a. Horizontal according to the direction of the main shaft: the horizontal position of the main shaft; vertical: the vertical position of the main shaft; inclined: the inclined position of the main shaft. b, according to the type of centrifugal impeller: Centrifugal centrifugal impeller; Francis: mixed flow impeller; Axial: Axial impeller. c, according to the way of inhalation Single suction: Single suction impeller; Double suction: Double suction impeller. d, according to the level of single-stage: equipped with an impeller; multi-level: the same shaft mounted two or more impellers. e, according to the blade installation method adjustable blade: impeller blade angle can be adjusted structure; fixed blade: impeller blade mounting angle is a fixed structure. f, according to the subdivision of the shell sub-type: the shell according to the plane perpendicular to the main axis of the subdivision; segmented: in the segmented structure in the form of each shell are separate; open: The housing is divided in the plane passing through the centerline of the shaft; horizontal open: in the open structure, the split surface is horizontal; vertical open: in the open structure, the split surface is horizontal Vertical surface; inclined to open: in the open, the split surface is inclined. g, according to the form of a pump scroll: impeller discharge side with a swirl chamber shell; double scroll shell: impeller discharge side of the shell with a double vortex chamber; Turbine: vaned centrifugal pump; barrel Bag type: the inner shell is equipped with a cylindrical pressure shell; double shell type: finger bag outside the double shell pump. h, according to the way the pump body suspension: Pump under the pump foot, fixed on the base, the bearing body hanging at one end; Bracket: the lower part of the bearing body fixed to the base, the pump body is supported by the bearing body One end; center support type: both sides of the pump body are fixed on the base on the horizontal plane passing through the axis. i, a special structure of the vane pump submersible pump: pump motor drive with the pump on the water used in the pump; Tubular pump: the pump body with motors and other drives; Shield pump: pump and motor direct connection (shared A shaft), inside the motor stator shield, to prevent liquid into the stator. Magnetic pump: the motor drives the external magnetic rotation, magnetic induction and the pump impeller connected with the inner magnet rotation, there is isolation between the inner and outer magnets, completely eliminate the liquid leakage; Self-priming pump: pump start again without irrigation Pump; Pipeline pump: The pump is installed as part of a pipeline and can be installed without special piping changes. Non-clogged pumps: Pumping of solid materials contained in liquids does not cause blockage in the pump. 3, the use of the pump Pump is a general machinery, many types, a wide range of applications, it can be said that in all sectors of the national economy, where there is liquid flow, said pump at work. Its main application areas are: farmland irrigation and drainage, petrochemical industry, power industry, urban water supply and drainage, mining and shipbuilding industries. In addition, pumps are also used in rocket fuel supply and ship propulsion.

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