Brief introduction, mechanical structure, classification, centrifugal pump, submersible pump, piston pump, micro-circulation pump, user's guide, used for submersible pump, self-priming pump, water pump maintenance, non-use storage, brief introduction of common pumps are piston pump, centrifugal pump and axial flow pump. The piston pump adopts atmospheric pressure, such as ordinary pressurized water pump. Centrifugal water pump uses the impeller to rotate, driving water to obtain centrifugal force, and water will rise to a high place, but the height of the suction port of centrifugal pump is still restricted by atmospheric pressure. Axial flow pumps are similar to electric fans, with rotating blades pushing water behind the pump shaft. Axial flow pump has a large flow, but the lift (lift) is not large. The basic structure of mechanical centrifugal pump consists of six parts, namely: impeller, pump body, pump shaft, bearing, sealing ring and stuffing box. Pump 1, impeller is the core component of centrifugal pump, its speed is higher than the force, and the blades on the impeller play a major role. The impeller must pass the static balance experiment before assembly. The inner and outer surfaces of the impeller should be smooth to reduce the friction loss of water flow. 2. The pump body, also known as the pump shell, is the main body of the pump. It plays a supporting and fixing role, and is connected with the bracket for mounting the bearing. 3. The function of the pump shaft is to connect with the motor through the coupling and transfer the torque of the motor to the impeller, so it is the main component to transfer mechanical energy. 4. Bearings are components that are sleeved on the pump shaft to support the pump shaft, including rolling bearings and sliding bearings. Plain bearings use transparent oil as lubricant. Add oil to the oil level. 5. The sealing ring is also called leakage reduction ring. 6. The stuffing box is mainly composed of packing, water seal ring, packing cylinder, packing gland and water seal pipe. The function of the stuffing box is mainly to seal the gap between the pump casing and the pump shaft, to prevent the water in the pump from flowing outward and the outside air from entering the pump. Always keep the vacuum in the water pump! When the pump shaft and the packing are heated by friction, it is necessary to cool the packing by putting water in the water seal ring by the water seal pipe! Keep the water pump running normally. Therefore, special attention should be paid to checking the stuffing box when the pump is running for inspection! After running for about 600 hours, the packing should be replaced. Centrifugal pump Centrifugal pump 1 and pump body, also known as pump shell, are the main body of water pump. It plays a supporting and fixing role, and is connected with the bracket for mounting the bearing. 2. The function of the pump shaft is to connect with the motor through the coupling and transfer the torque of the motor to the impeller, so it is the main component to transfer mechanical energy. 3. Bearings are the components that are sleeved on the pump shaft to support the pump shaft, including rolling bearings and sliding bearings. Rolling bearings should be properly coated with butter as lubricant, generally 2/3 ~ 3/4. If the volume is too large, it will generate heat, and if it is too small, it will generate noise and heat! Plain bearings use transparent oil as lubricant. Add oil to the oil level. Too much oil will seep out and drift along the pump shaft, and too little bearing will overheat and burn out, causing accidents! During the operation of the water pump, the maximum temperature of the bearing is 85 degrees, and it usually runs around 60 degrees. If it is high, it is necessary to find out the reason (whether there are impurities, whether the oil is black, whether it is flooded) and deal with it in time! 4. The sealing ring is also called leakage reduction ring. The gap between the impeller inlet and the pump casing is too large, which will cause the water in the high pressure area of the pump to flow to the low pressure area through this gap, which will affect the water output of the pump and reduce the efficiency! If the clearance is too small, the friction between the impeller and the pump casing will cause wear. In order to increase reflux resistance, reduce internal leakage and prolong the service life of the impeller and the pump casing, a sealing ring is installed at the joint between the inner edge of the pump casing and the outer edge of the impeller, and the sealing gap should be kept between 0.25 ~1.10 mm. The working principle of centrifugal pump The working principle of centrifugal pump is that the liquid depends on the high-speed rotating impeller to obtain energy under the action of inertial centrifugal force to increase the pressure, and before the pump works, the pump body and inlet pipe must be filled with water. When the impeller rotates rapidly, the blades urge the water to rotate rapidly, and the rotating water flies away from the impeller under the action of centrifugal force. After the water in the pump is thrown out, the central part of the impeller forms a vacuum zone. Under the action of atmospheric pressure (or water pressure), water from the water source is pressed into the water inlet pipe through the pipe network. In this way, continuous pumping can be realized. It is worth mentioning that the centrifugal pump must be filled with water before starting, otherwise it will cause the pump body to heat and vibrate, reduce the water output, damage the pump (referred to as "cavitation"), and cause equipment accidents! Cavitation refers to the phenomenon that when a centrifugal pump is started, if there is air in the pump, the centrifugal force generated after the rotation is very small due to the low air density, so the low pressure formed in the central area of the impeller is not enough to suck the liquid with the liquid level lower than the pump inlet into the pump, and the fluid cannot be transported. Classification of centrifugal pumps There are many kinds of centrifugal pumps. The common classification methods are as follows: 1. According to impeller suction, there are single-suction centrifugal pumps and double-suction centrifugal pumps. 2. According to the number of impellers: single-stage centrifugal pump and multi-stage centrifugal pump; 3. According to the impeller structure: open impeller centrifugal pump, semi-open impeller centrifugal pump and closed impeller centrifugal pump; 4. According to working pressure: low-pressure centrifugal pump, medium-pressure centrifugal pump and high-pressure centrifugal pump; 5. According to the position of the pump shaft: horizontal centrifugal pump and vertical centrifugal pump. Submersible pump 1. Select standardized water pump 1. What is a standardized water pump? Standardized water pump is the latest model of water pump formulated and implemented by the state according to the requirements of ISO. Its main features are small size, light weight, excellent performance, convenient operation, long service life and low energy consumption. It represents the latest trend of the current water pump industry. Submersible pump 2. How to choose a water pump? When users choose water pumps, it is best to go to the sales point recognized by the agricultural machinery department, and the manufacturers must recognize it clearly. It is recommended to give priority to the purchase of water-filled submersible pumps, and the brand and product quality certificate should be clearly seen. Never buy "three noes" (that is, no manufacturer, no production date and no production license) products, otherwise there will be problems and users will be helpless. 3. What brand of water pump is good? As a user, due to the limitation of professional knowledge, it is difficult to decide. The best way is to consult a water pump expert. If you really can't find someone to consult, it is a wise choice to consult some old water pump users, especially those who are close to their own use conditions, and buy products that users trust, have reliable quality and are relatively mature. At the same time, it is necessary to decide whether to use single-phase pump or three-phase pump according to the local power supply situation. Second, choose a pump that meets the lift requirements. 1, pump head selection. The so-called lift refers to the required lift, not the height of lifting water, so it is particularly important to make it clear for selecting pumps. The lift of the pump is about 1. 15 ~ 1.20 times of the lifting height. For example, the vertical height from a water source to the water use site is 20 meters, and the required lift is about 23 ~ 24 meters. When selecting a water pump, the lift on the nameplate of the water pump should be close to the required lift. In this case, the water pump is the most efficient and will be more economical to use. However, absolute equality is not necessarily required. Generally speaking, as long as the deviation does not exceed 20%, the pump can work in a relatively energy-saving situation. 2. What is the lift of the nameplate? Choosing a pump whose lift on the nameplate is far less than the required lift will often fail to meet the user's wishes. Even if it can pump water, the amount of water is pitiful, and it will even become a useless "idle pump". Is it better to buy a pump with a higher lift? Actually, it is not. When high-lift pump is used for low-lift, the flow will be too large, which will lead to motor overload. If the motor runs for a long time and the temperature of the motor rises, the winding insulation will gradually age and even burn the motor. Third, choose the appropriate flow pump. The flow rate of the pump, that is, the water output, should generally not be too large, otherwise it will increase the cost of purchasing the pump. Specific analysis of specific problems, such as the self-priming pump used by users to draft their own water, the flow rate should be as small as possible; If users use submersible pump for irrigation, they can choose one with larger flow. Piston pump is also called "suction pump". The water inlet pipe at the lower part of the machine body is inserted into the water. The water pump is a cylinder with a piston, which can slide up and down and closely cooperate with the cylinder wall. There are valves v 1 and v2 at the bottom of the cylinder and the piston, which can only be opened upward. When in use, if the piston moves upward, the valve v2 is closed under the action of atmospheric pressure, and the air under the piston is thin, and the atmospheric pressure is less than the external atmospheric pressure. Then, the lower water is pushed into the cylinder by atmospheric pressure. When the piston presses down, the valve v 1 at the bottom of the cylinder is closed by the pressure of water, which prevents the water from flowing downwards, so the valve v2 is pushed up and the water enters the upper part of the cylinder. When the piston is lifted again, the water above the piston closes the valve v2 and the water flows out from the side pipe. At the same time, the water in the well pushes open the valve v 1 under the action of atmospheric pressure and enters the circular tube. In this way, the piston keeps moving up and down, and water keeps flowing out of the nozzle. This kind of pump is simple in structure and convenient to operate, but the water output is small, the water lifting height can only reach about eight meters, and the efficiency is also low. 1, before starting the pump, the suction pipe and pump must be filled with liquid. After the pump is started, the impeller rotates at high speed, and the liquid inside rotates with the blades. Under the action of centrifugal force, it flies off the impeller and shoots outward. The speed of the liquid sprayed from the diffusion chamber of the pump shell gradually slows down, the pressure gradually increases, and then it flows out from the pump outlet and the discharge pipe. At this time, because the liquid is thrown around, a vacuum low-pressure area with neither air nor liquid is formed in the center of the blade. Under the action of atmospheric pressure on the pool surface, the liquid in the liquid pool flows into the pump through the suction pipe, so that the liquid is continuously pumped up from the liquid pool and continuously flows out from the discharge pipe. The working principle of piston pump The working principle of piston pump is also called suction pump, which uses the movement of piston to discharge air, causing the pressure difference between inside and outside to make water rise and be pumped out under the action of air pressure. When the piston is pressed, the water inlet valve is closed and the exhaust valve is opened. When the piston is lifted, the exhaust valve is closed and the water inlet valve is opened. Under the action of external atmospheric pressure, water flows from the water inlet pipe to the upper water outlet through the water inlet valve. In this way, the piston reciprocates up and down in the cylinder, constantly pumping out water. Note: both piston pumps and centrifugal pumps use atmospheric pressure to pump water up. Because the atmospheric pressure is limited, the pumping height of the pump is also limited, not exceeding 10. Micro-pump with micro-circulation pump can be used for water circulation cooling because of its many functions, and is often called micro-circulation pump. It has a water inlet and a water outlet, and can continuously form vacuum or negative pressure at the inlet; Forming a large output pressure at the drain; The working medium is water or liquid; A small instrument. There are also micro-liquid pumps, micro-pumps, micro-pumps. The characteristic of various micropumps is 1. Micro-AC Pump Micro-AC Pump Micro-AC Pump The commutation of the micro-AC pump is changed by the frequency of 50HZ of the commercial power, and the rotation speed is very low. There are no electronic components in the AC pump, which can withstand high temperature. The volume and power of AC pump with the same lift are 5- 10 times that of DC brushless pump. Advantages: the price is cheap and there are many manufacturers. 2. Brushed DC water pump: When the water pump works, the coil and commutator rotate, while the magnetic steel and carbon brush do not move. The alternating change of coil current direction is completed by the motor driving the commutator and brush to rotate. As long as the motor rotates the carbon brush, it will wear out. After the computer water pump runs for a certain period of time, the wear gap of the carbon brush will increase and the sound will also increase. After hundreds of hours of continuous operation, the carbon brush can't play the role of commutation. Advantages: low price. 3. Brushless DC electric pump: Brushless DC electric pump consists of brushless DC motor and impeller. The shaft of the motor is connected with the impeller, and there is a gap between the stator and the rotor of the water pump. After a long time of use, water will penetrate into the motor, increasing the possibility of motor burning out. Advantages: Brushless DC motors have been standardized and mass-produced by professional manufacturers, with low cost and high efficiency. 4. Brushless DC magnetic drive water pump: Brushless DC magnetic drive water pump adopts electronic components for commutation, instead of carbon brush for commutation, and adopts high-performance wear-resistant ceramic shaft and ceramic sleeve, which are integrally formed with magnets through injection molding to avoid abrasion, so the service life of brushless DC magnetic drive water pump is greatly enhanced. The stator and rotor of the magnetically isolated water pump are completely isolated. Stator and circuit board are encapsulated with epoxy resin, 100% waterproof. The rotor is made of permanent magnets, and the pump body is made of environmentally friendly materials, with low noise, small volume and stable performance. Various required parameters can be adjusted by winding the stator, and it can work under wide voltage. Advantages: long service life, low noise below 35dB, and can be used for hot water circulation. The stator and circuit board of the motor are encapsulated by epoxy resin, which is completely isolated from the rotor, and can be installed underwater and completely waterproof. The water pump shaft adopts high-performance ceramic shaft, which has high precision and good seismic performance. Correctly mastering the use method is an important factor to prolong the life of the pump and reduce the economic loss. Before starting the submersible pump, some necessary inspections should be carried out: whether the pump shaft rotates normally and whether there is jamming; Whether the position of the impeller is normal; Cables and cable plugs are free from cracks, scratches and fractures. Pay attention to the change of voltage during operation, and generally control it within 5% of the rated voltage. In addition, the position of the pump in the water is very important. Try to choose a place with abundant water, no sediment and good water quality, and hang it vertically in the water. It is not allowed to be placed horizontally, so as to avoid falling into mud or being blocked by suspended matter at the entrance of the pump, resulting in a sharp drop in water output or even inability to pump water. The self-priming pump should be placed in a well-ventilated place as far as possible to facilitate rapid heat dissipation and reduce the motor temperature. Otherwise, it is easy to burn out the motor after running for a long time. For example, when a farmer used a self-priming pump, the plastic film covering the motor was not removed, which caused the motor to overheat and burned the coil. In addition, before starting, be sure to check the water storage in the pump body, otherwise it will not only affect the self-priming performance, but also easily burn out the shaft seal parts. Under normal circumstances, the water should be discharged within 3 ~ 5 minutes after the pump is started, otherwise it should be stopped immediately for inspection. Maintenance of water pump When the water pump fails, do not disassemble it by yourself. Because when I dismantled it myself, first, I didn't know where the fault was, which led to blind dismantling; Second, there is no special tool, which often damages the original intact parts. The best way is to go to an experienced large-scale maintenance point for maintenance and replace "over-aged" parts and some wearing parts in time. Under normal circumstances, the water pump should be maintained once every six months to prevent "sick" work. If the pump is stored during non-use, it should be hoisted away from the water source in time, and the accumulated water in the pump should be discharged, especially in cold winter. Then put it in a dry place. Conditional users can also apply butter to the key parts of the water pump and add lubricating oil to the bearings to prevent the parts from rusting. In addition, the non-use period of the pump is not as long as possible. If it is not used for a long time, it will not only corrode parts, but also reduce the service life of the pump.