Introduction to the basic structure of a centrifugal pump is composed of six parts, respectively impellers, pump, pump shaft, bearings, seal rings, stuffing box. 1, is a core part of the centrifugal impeller, which speed up force, the blades on the impeller also played a major role in the assembly before the impeller through the static equilibrium experiments. The inner and outer surfaces of the impeller required to be smooth to reduce flow friction losses. 2, pump, also known as the pump casing, which is the main water pump. Fixed play a supporting role, and connected with the installation of the bearing bracket. IMG_20141104_095307 3, the role of the pump shaft and the motor is connected by the coupling, the torque of the motor is transferred to the impeller, so it is the transmission of mechanical energy of the main member. 4, the sliding bearing using a clear oil as a lubricant, the fuel to oil level line. To much oil leaking along the shaft, bearings and also too hot to burn accident! In the course of the operation of the pump bearing the highest temperature of 85 degrees, usually run at about 60 degrees. 5, sealing ring, also known as reduced leakage ring. 6, stuffing consists of packing, lantern ring, packing tube, packing gland, seal tube. The main role of the stuffing box gap is to be closed between the pump housing and the shaft, to prevent the water flowing out from the pump to not let outside air into the pump. Always keep the vacuum pump inside! When the shaft and packing friction heat to rely on the seal to seal the circle take control of water to cool the filler! Maintain the normal operation of the pump. Therefore, the inspection process is running tour of inspection of the pump stuffing is particularly pay attention! 600 hours running around going on packing replacement. 2 product analysis of the basic structure of the basic structure of the centrifugal pump is composed of eight parts, namely: impeller, pump, pump cover, retaining ring, shaft, bearings, seal rings, stuffing, axial force balancing device. 1, is a core part of the centrifugal impeller, which speed and high output force. 2, pump, also known as the pump casing, which is the main water pump. Fixed play a supporting role, and connected with the installation of the bearing bracket. 3, the role of the pump shaft and the motor is connected by the coupling, the torque of the motor is transferred to the impeller, so it is the transmission of mechanical energy of the main member 4, the sealing ring also known leak reducing ring. 5, stuffing consists of packing, do not let the water flow out of the pump to not let outside air into the pump. Always keep the vacuum pump inside! When the shaft and packing friction heat to rely on the seal to seal pipe water cooling circle the filler! 6, the axial force balance device, centrifugal pump is running, because the liquid is at low pressure into the impeller, and the outflow at high pressure, ranging from pressure on both sides of the impeller, resulting in the entry point to the direction of the axial thrust, will cause the rotor axial movement occurs, resulting in wear and vibration, and therefore should be set axial thrust bearing, in order to balance the axial force. One species, according to the classification of a number of impeller, single-stage pump: that is, in only one of the impeller shaft. 2, multi-stage pump: i.e., the pump shaft has two or more impellers, then for the total head of the pump head of the impeller and the n. IMG_20141104_092632 two, according to the working pressure to classify a low-pressure pump: pressure is below 100 meters of water; 2, medium-pressure pump: pressure is between 100 to 650 meters of water; 3, high-pressure pump: pressure is higher than 650 meters of water. Third, according to Impeller method to classify a unilateral water pump: also known as single-suction pump, that the impeller is only one intake; 2, bilateral water pump: also known as double suction pump, that both sides of the impeller has an intake. It's twice the size of a single flow-priming pump, can be approximated as two single-suction pump impeller put together back to back. Fourth, according to the classification of a combination of the pump casing, horizontal split pumps: that is, in the horizontal plane through the axis opened a seam binding. 2, the vertical joint surface pump: the combination of surface perpendicular to the shaft axis. Five, according to the classification of a shaft position, horizontal pumps: shaft in a horizontal position. 2 Horizontal pumps Horizontal pumps, vertical pumps: shaft in a vertical position. Six, according to the classification of a way out of the impeller, volute pump: water from the impeller out directly into the pump casing has a spiral shape. 2, guide vane pump: water from the impeller out into it set out vanes, then enter the next level or into the outlet pipe. Seven, according to the classification of a mounting height, self-filling centrifugal pumps: shaft below the pool deck pool suction, irrigation is not required when you start, you can start automatically. 2, suction centrifugal pumps (centrifugal pumps non-self-filling): shaft above the suction surface of the pool basin. Before you start, you need to be filled with water pump casing and suction pipe, then the drive motor, the impeller speed rotation, water was thrown by the centrifugal force of the impeller, the impeller center negative pressure, water in the pool water at atmospheric pressure into the impeller action but also by the role of the high-speed rotation of the impeller, the impeller was thrown into the pressurized water pipes. In addition, it can be classified according to use, such as oil and water pumps, condensate pumps, ash pumps, circulating pumps. Characteristics by means Single suction pump liquid into the impeller from the side, there is a double suction pump axial force liquid into the impeller from both sides, there is no axial force, the pump flow by almost doubling the number of stages than single-stage single-suction pump Only one pump shaft multistage pump impeller shaft with a coat of two or more impellers, the liquid flows through every stage impeller, the series, the more the higher lift shaft by horizontal orientation Horizontal Vertical shaft perpendicular to the horizontal shaft type segmented by the housing by the pump housing portion and the plane perpendicular to the axis, between the segment and the segment is connected with a long bolt in the open pump housing in a plane through the axis of the split spiral volute pump fitted centrifugal pump pressurized water chamber, as usual end-suction pumps cantilever centrifugal turbine vane type air-pressurized water chamber of centrifugal pumps as part of the special structure of the pipe lines, no need to install changes in pipeline submersible pumps and motors made integral liquid immersion under water pump body immersed in liquid pump impeller and motor rotor shield together as one, and in the same sealed housing, without the use of sealing structure, belonging to no leakage magnetic pump pump In addition to the import and export, fully enclosed pump, pump and motor coupling using self-priming pump is driven magnet mutual suck without irrigation fluid pump when the pump is started by the high-speed growth of the box so that the shaft speed increases, the general speed of up to 10000r / min or more, can also be called partial flow booster pump or tangent vertical barrel pump and export the same height in the upper takeover, there are inner and outer layers of the housing, in the housing by the rotor, vanes and other components, shell for the import diversion channel, the liquid from the lower inhalation. ISG live feed pump, pump life, residential water pumps, water supply and drainage equipment life, according to IS, IR type centrifugal pump performance parameters and the unique structure of a combination of vertical pump design, and in strict accordance with ISO2858 requirements for design and manufacturing, the use of domestic high-quality hydraulic model design is made, is the best of a new generation of horizontal pumps. The products are used carbide mechanical seal. Applications: ISW pumps for industrial and urban drainage, such as high-rise building pressurized water, garden irrigation, fire booster, long-distance transportation, HVAC refrigeration cycle, bathroom, and equipment for pressurized, temperature does not exceed 85 ℃. ISWR pumps widely used in: metallurgy, chemical, textile, paper, as well as shops, restaurants Bin pressurized boiler heat water, transportation, and urban heating systems, SGWR type temperature does not exceed 120 ℃. Use pump commissioning shall meet the following requirements: ① driver should turn the steering pump is the same; ② identify pipeline pump and coaxial steering pump; ③ each fixed connection should be no loose parts, each filling lubricant lubrication The size and number of equipment shall comply with the technical documentation; ④ there are pre-lubricated parts should be required to carry out the required pre-lubricated; ⑤ each indicating instruments, safety protection device should be sensitive, accurate, and reliable; ⑥ disk drive should be flexible, no abnormal phenomenon; ⑦ high temperature pump before commissioning the pump should be preheated, the temperature should rise evenly, hourly temperature should not exceed 50 ℃; pump temperature difference between the surface and have a working medium import process piping should not exceed 40 ℃; ⑧ Set the connection device to eliminate the impact of temperature rise, setting a bypass connecting device to provide cooling water. Centrifugal operation should note the following: ① prohibits run dry, do not adjust the suction to reduce emissions, prohibit running at low flow; ② When the monitoring process runs completely prevent leakage of packing boxes, packing boxes must replace with a new filler; ③ ensure adequate mechanical seal flushing water, water-cooled bearing prohibit the use of excess water; ④ Do not use too much lubricant; ⑤ according to the recommended inspection cycle. Establish operational records, including hours of operation, adjustment and replacement filler, lubricant and other maintenance measures and time. Centrifugal pump suction and discharge pressure, flow, temperature, and vibration input power, lotions and bearings should be measured regularly records. ⑥ hosts rely on atmospheric pressure centrifugal water pumped at low height, and atmospheric pressure can only support up to approximately 10.3m in the water column, so the centrifugal pump out of the water 12 meters host does not work. Maintenance 3.1, pump mechanical seal failure analysis of a centrifugal pump is mainly composed of downtime caused by failure of the mechanical seal. Failure of performance, mostly leaks, leaks following reasons: ① static ring sealing surface leakage, the main reasons are: the end surface flatness, roughness does not meet the requirements, or surface scratches; between the end face of particulate matter, resulting in two The same can not run end face; installation is not in place, the wrong way. ② compensation ring seal leakage, the main reasons are: gland deformation, uneven preload; not properly installed; seals do not meet quality standards; seals wrong selection. Actual results show that the failure of most parts of the sealing element is dynamic and static ring end face, pump mechanical seal dynamic and static ring face is a common failure occurs cracking phenomenon, for two main reasons: ① When installing the sealing surface of the gap is too large, washes away the heat of friction produced too late; the fluid leakage from the sealing surface gap go, causing damage to the end face of overheating. ② vaporized liquid medium expands, so both end surfaces separated by vaporization expansion force, when the two sealing surfaces of bonding force, thereby causing damage to the end face of the lubricating film surface overheating. ③ Liquid medium poor lubrication, combined operating pressure overload, both seal faces trace rotation is not synchronized. For example, high speed pump speed is 20445r / min, diameter of the sealing surface center 7cm, after the pump is running its line speed up to 75 m / s, when there is a lag can not track the rotating seal face, the instantaneous high temperature caused by damage to the sealing surface. ④ seal flush fluid plate or filter is clogged, causing water shortage, making mechanical seal failure. In addition, the sealing surface of the surface slippery ditch, face a gap of bonding leads to failure of the sealing elements, for two main reasons: ① dirty liquid medium, there are small hard particles at high speed sliding sealing faces who will draw a facing surface injury and failure. ② pump coaxial transmission parts is poor, the pump is turned on every revolution of the end surface friction was shaking once, different ring trajectory heart, causing the end face of vaporization, thermal wear. ③ liquid medium hydraulic characteristics of pump vibration caused by frequent, resulting in the sealing surface dislocation and failure. Liquid medium of the corrosion of the sealing member, stress concentration, with the hard and soft materials, erosion, secondary seal 0-ring, V-ring, is incompatible with the liquid medium concave ring, deformation can cause mechanical failure of the sealing surface is damaged, so To their damage in the form of a comprehensive analysis to identify the root causes and ensure the long-running mechanical seals. 3.2, pump stopped functioning after the request ① stopped after the centrifugal pump of the population should be closed valves to be closed in order to cool down the pump valve subsidiary system. ② high temperature pump provides parking facilities shall perform technical documents, parking should be every 20 to 30min jigger partial semi-circle until the pump until the temperature dropped to 50 ℃. ③ When the cryogenic pump stop, when no special requirements, the pump should always be filled with liquid; suction and discharge valves should be kept normally open state; using double mechanical seal of cryogenic pumps, liquid level controller and pump seal cavity sealing liquid grout pump pressure should be maintained. ④ delivery pump easy to crystallize, easy to solidification, easy precipitation and other media, after stopping the pump should prevent clogging, and promptly flushed with water or other medium, pumps and pipelines. ⑤ accumulation of liquid in the pump discharge to prevent corrosion and cracking. 3.3 ① custody centrifugal pump has not been installed unpainted surfaces should be coated with a suitable rust, oil lubricated bearings should be filled with a suitable oil, grease lubricated bearings should be filled only a grease, do not use mixed grease. ② short pumped clean liquid, flushing, suction line, discharge line, pump housing and impeller, the pump housing net side by side, the suction line and discharge line of the flushing fluid. ③ drain the oil bearing housing, reraise clean oil, grease thoroughly cleaned and refilled with new grease. ④ the suction and discharge ports sealed population, the pump stored in a clean, dry place, protect motor windings from moisture, liquid rust and corrosion with a liquid jet pump housing interior. ⑤ shaft rotates once a month so as not to freeze, and lubricate the bearings. Start a former centrifugal pump to start the preparatory work started before the name of a centrifugal pump Check the oil, model, and raises the number of key performance meets the requirements of technical documentation; bearing lubrication system, sealing system and cooling system is intact, bearing of the oil, water is smooth; move the pump rotor disc 1 to 2 to check whether there is friction or rotor stuck phenomenon; in the vicinity of the coupling or belt guards, etc., if there interfere with the rotation of debris; pump, bearing, motor foundation anchor bolts are loose; valve or pump attachment system should be in the position of minimum load when the pump is running, you should close the outlet valve; inching pump, to see whether the steering wheel is consistent with the design of the steering If not, it is necessary that the impeller is fully stopped, the motor terminal after adjustment before restarting. b. centrifugal pumps filled with water before the start, the pump housing must be filled with water and suction pipe, which is due to the presence of air under the circumstances, can not form a vacuum pump intake and maintain. c. centrifugal pumping hot liquids warm multi-stage centrifugal pumps, power plants, such as boiler feed pumps must be warm before starting the pump. This is because the feed pump at startup to the high temperature water flows through the pump, so that the pump body rises quickly from room temperature to 100 ~ 200 ℃, which causes the temperature difference between internal and external pump and between the various components, if not long enough transfer time and proper temperature control measures throughout the pump will inflate uneven, resulting in various parts of the pump body deformation, wear, vibration and bearing axle accident. Two, to pay attention vane pump is a centrifugal pump, relying on the rotating impeller during rotation, due to the interaction of the blade and the liquid leaves the liquid for imparting mechanical energy, can increase the pressure of the liquid, to achieve the purpose of transmission fluid. Centrifugal starting to pay attention to four points: ① head at a certain speed centrifugal produced a limited value. Operating point flow and shaft power depending on the device system connected to the pump case (difference, pressure difference, and line losses). Lift with the flow and change. ② stable, continuous delivery, flow and pressure pulsation. ③ generally no self-absorption capacity, the need to be filled with a liquid pump or evacuated after the pipeline can begin work. ④ centrifugal valve in the discharge line to start off, whirlpool and axial pumps in the valve is fully open state to start to reduce the starting power. Because centrifugal impeller centrifugal force is by vacuum suction to lift the water, so when the centrifugal start, you must first close the valve, irrigation. Parts above the water level exceeds the impeller, centrifugal pump discharge air before startup. After starting to form around the impeller vacuum to suck up the water, which can automatically open the valve, the water lifted. Therefore, you must first close the valve. Vibration Analysis 1. centrifugal rotor unbalance and misalignment. This problem centrifugal vibration problems in a larger proportion, about 80% ratio. Centrifugal rotor unbalance factors: material to prevent uneven parts of the structure failed, causing the rotor shaft centerline and the quality does not coincide with the center line of the eccentric According produce unbalanced formation. Centrifugal rotor unbalance correction can be divided into two. Static and Dynamic Balancing: General, also known as single-sided and double-sided balance balance. The difference is this: on one side the balance is calibrated balance in front of a school, and the balance is in the two-sided surface correction correction. 2. Install the reason: the foundation bolts loose, levelness school transfer is not adjusted before centrifugal work, to check whether its foundation bolts loose phenomenon, as well as the installation of a centrifugal pump is horizontal. These conditions can also cause the occurrence of centrifugal vibration at work. 3. Centrifugal foreign body inside. Before centrifugal pump, the internal pump to check the next, due to the long-term use, there may be some differences such as weeds, such as water inside the centrifugal pump. 4. due to prolonged use of centrifugal pump cavitation caused perforation. Unreasonable design 5. centrifugal presence, such as parts of sizes and other issues. However, relatively few such cases. Before playing a centrifugal pump, the workshop will be multiple internal testing work to ensure that the passing rate of the factory centrifugal pump. The main performance of a centrifugal pump power and the pump efficiency during operation due to various losses, so that the actual pump (valid) pressure head and flow rate lower than those of the theoretical value, and the input pump power is higher than the theoretical value, provided H______ effective pressure head of the pump, the energy per unit volume of liquid in the gravitational field is obtained from the pump, m; actual flow Q ______ pump, m3 / s; ρ ______ liquid density, kg / m3; Ne______ effective pump power, i.e., the unit within the time obtained from the liquid at the pump mechanical energy, W. Effective power can be written as Ne = QHρg shaft power from the motor input power is called centrifugal pumps to N represents. Effective power ratio is defined as the total shaft power and pump efficiency η, i.e., η = Ne / N two, various types of losses within the centrifugal pump loss are: loss of (1) the volume loss due to leakage caused by the pump is called volume loss. When there is no volume loss of the pump power loss when the volume ratio of the power of the pump is called the pump volumetric efficiency ηv. (2) loss of hydraulic fluid to flow through the impeller, the pump housing, there is a change in the pressure gradient and inverse velocity magnitude and direction caused the circulation and vortex, resulting in energy loss, this loss is called hydraulic loss. Rated flow centrifugal pump hydraulic efficiency ηh generally 0.8 to 0.9. And bearing friction losses, etc. The mechanical friction seal (3) high-speed rotation of the mechanical loss between the impeller and the liquid is called mechanical loss caused. Mechanical efficiency ηM generally 0.96 to 0.99. Note: 1, the main performance parameters of the centrifugal pump nameplate is 20 ℃ water for experiments under conditions of maximum efficiency measured values. 2, to understand and master the characteristic curve of each curve meaning and conditions of use, attention span most efficient area (η = 92% ηmax) and uses. 3 advantages of compact structure a wide range of flow and head wide range applicable to a variety of control options mildly corrosive liquid flow evenly, smooth operation, small vibration. No special damping foundation. Equipment installation, maintenance and lower maintenance costs.