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"Pump and Pump Station" Experimental Guide Jiang Yanli compiled Liaoning Engineering University Civil Engineering and Architecture Engineering Experiment a leaf pump basic structure and parts understanding 1, the purpose and requirements of the experiment (1) to understand the structure and working principle of the vane pump, to further (2) Understand the main components of the vane pump and understand the structure and function of the main components of the vane pump (3) Establish the perceptual knowledge of the flow of the water flow in different types of vane pumps. (4) Understand Pumping device composition and the role of pipeline accessories .2, the experimental content (1) observe the centrifugal pump, mixed flow pump and axial flow vane pump objects and wall charts; (2) the students do it yourself disassemble the three vane pumps (3) show the basic structure of the pump video or slide; control the physical characteristics and working principle of the vane pump; (4) refer to the pumping equipment and piping accessories to explain the pump pumping device The composition and the role of the pipeline attachment .3, experimental equipment centrifugal pump, mixed flow pump, axial flow pump, other pumps, pumping equipment, demolition tools, wall charts, etc .. IS type single-stage centrifugal water pump structure diagram 4 Steps and precautions (1) Removal of the pump cover: Before the demolition of the pump cover and the pump body should be marked at the junction, unscrew the nut, you can remove the pump cover, if too tight can be top jack to lift the pump cover (2) Disassembly of the impeller: 1. Remove the impeller fixing device: Open the retaining washer that locks the impeller nut; Remove the impeller's counter-retaining nut and retaining washer with special or common tools.2 Remove the impeller: Screw the two special tools into the two threaded holes in the balance hole, the positive spindle end, slowly turn the handle to pull out the impeller; if the impeller rust on the shaft and pull Not move, you can brush a little kerosene at the key joint, wait a moment, you can pull out the impeller. (3) After removing the impeller, you can remove the flat key, the sleeve and the mechanical shaft seal device Ring (4) Disassembly of the pump body: The pump body is screwed with the bearing seat, the markings should be made before dismantling, then the nut is removed, the pump body is removed, and the static ring is removed from the pump body. ) Disassembly of the pump coupling: 1. Unscrew the locking cap of the fixed coupling 2. Pull out the coupling slowly from the shaft end with a special pull (puller) Screw must be top positive pump shaft center, So that the coupling on both sides of the force evenly, can not be pounded by hand hammer, so as to avoid damage to the pump shaft, bearings and coupling.If not down, you can use cotton yarn dipped in kerosene, combustion along the coupling around Its uniform thermal expansion, so that it will be easy to remove, but in order to prevent the shaft and the shaft together with the thermal expansion, the wet shaft to wrap the pump shaft (6) bearing removal: first remove the bearing housing on the front and rear two bearing caps, Then use a wooden pad on the shaft end of the coupling and tap the wooden block with a hand hammer to remove the shaft together with the bearing. Take special care when removing the bearing from the shaft and do not damage the bearing , Generally with a special bearing pull to demolition, pull the hook must grasp the bearing inner ring.If the bearing and the pump shaft is very tight, the oil can be heated to 100 ℃, with oil pot poured (7) Clean the parts after disassembly with kerosene or light diesel oil, and place them in order to prepare for inspection and measurement. (8) Precautions: 1 . Tools used in the selection, proper and proper: 2. Disassembly or assembly process is correct .3. Some important components should be marked before demolition to prepare complex Bit .4 disassembled parts and components should be properly placed to prevent the loss of .5 pairs of joints and easy to bump place, need to take the necessary protective measures .6 process properly, in line with technical specifications .7 tools finishing (2) how to replace the packing experiment 2 Determination of centrifugal pump characteristic curve 1, the purpose and requirements of the experiment through the centrifugal pump performance test deepen Centrifugal pump performance curve to understand the centrifugal pump performance curve of the conventional test methods, including: understanding of the performance of experimental devices, to master the measurement and calculation of performance parameters, the performance curve drawn, analysis of experimental results.2, the basic principle of centrifugal Pump is a kind of liquid conveying machinery, which takes advantage of the high speed rotation of the pump impeller, so that the liquid filled in the pump body is thrown from the center of the impeller to the edge under the centrifugal force. During this process, the liquid gains energy and increases the static Pressure energy and kinetic energy.When the liquid leaves the impeller and enters the shell, some of the kinetic energy becomes static pressure energy due to the increase of the flow cross-sectional area, which further increases the static pressure energy.The amount of energy provided by the fluid depends not only on the Knot Structure and speed, but also with the fluid density.When there is air in the centrifugal pump, the air is much heavier than the liquid centrifugal force generated by the centrifugal pump is insufficient to form the required degree of vacuum at the pump inlet, can not inhale Liquid, the phenomenon known as "gas tied." In order to ensure the normal operation of the centrifugal pump, the centrifugal pump and suction line must be filled with liquid before starting and to ensure that the operation as much as possible to prevent air leakage in. Centrifugal pump main Performance is the head, flow, power, efficiency and speed. At a certain speed, centrifugal pump head, power, efficiency changes with the size of the flow. Head and flow characteristics of He = f (Qe), power consumption and flow Of the characteristic curve of the centrifugal pump N axis = f (Qe), and the efficiency and flow characteristics of the curve η = f (Qe) is the centrifugal pump of the three characteristics. They are centrifugal pump design, manufacture, must be determined experimentally. The Qe and N-axis in the curve are directly determined experimentally, and He and η can be calculated using the formula: From Bernoulli's equation: where: He is the head of the pump, m column of liquid, H is the pressure of the pump Gauge measured pressure, m liquid column); H vacuum gauge - vacuum gauge measured true Degree, m liquid column;  h0-- vertical distance between the pressure gauge and the center of the vacuum table, m; u2-- velocity of the fluid in the pump outlet tube, m / s;  u1-- velocity of the fluid in the pump inlet tube, m / s . The actual effective power obtained after the fluid has passed through the pump: where: ¾ He - the effective power of the centrifugal pump, kW;  Qe - the infusion volume of the centrifugal pump, m3 / s; Ï - Liquid density, kg / m3. The total efficiency of the centrifugal pump: Where type: N electric - motor input power, kW. 3, the experimental flow chart 4, the experimental steps (1) before the experiment, closed (2) Turn on the water inlet valve and the air release valve, turn off the water source, water inlet valve, and air release valve after the water filling pump is fully charged. (3) Turn on the water meter, Start the pump, switch on the power meter switch (4) open the pump outlet valve, adjusted to a minimum (= 0), record flow meter, pressure gauge, vacuum gauge, power meter reading. (6) At the end of the experiment, open the power meter switch, turn off the power to the pump and the turbine flow meter, and the experimental device should be restored to its original state. Clean the experimental site .5, experimental data record table device number; water temperature; instrument constant; centrifugal pump model; head; flow; serial number display instrument times / s vacuum gauge pressure gauge power meter diameter: into; out; 6, the data table No. Flow θ (m3 / h) Head H (m) Power N (KW) Efficiency η7, the experimental report  (1) The experimental data obtained and calculated by the calculated parameters on the coordinate paper Make three characteristic curves;  head and flow characteristic curve He ~ Qe. power consumption and flow characteristic curve N-axis ~ Qe. power and flow characteristic curve η ~ Qe. (2) experimental result discussion and analysis 8 , Thinking questions (1) why the centrifugal pump in the start before the start Drainage pump If you have dived irrigation pump but the centrifugal pump still does not start up, what do you think may be why the solution (2) why the centrifugal pump starts to close the outlet valve And pull down the power meter switch (3) Why adjust the outlet valve of the centrifugal pump to adjust its flow What are the advantages and disadvantages of this method is there any other way to regulate the pump flow (4) the normal operation of the centrifugal pump in its inlet pipe On the valve is reasonable, why (5) why Install low-energy-saving valve from the point of view, whether favorable bottom valve installed at the heart pump inlet pipe do you think should be how to improve