外文翻译题 目 离心泵学生姓名 冯涛专业名称 机械设计制造及其自动化指导教师 史革盟2012 年5月18日Centrifugal pumpThe concept of centrifugalCentrifugal inertia is the performance of an object, such as umbrellas on the water droplets, when the umbrella slowly rotating, the water droplets will follow the umbrella rotation, because the umbrella and the friction of water droplets to drop as the centripetal force of shiran. However, if the umbrella rotation speed, the friction enough to make water droplets in a circular motion, then drop the sport from the umbrella to the outer edge, like a rope pulling the stones to do with circular motion, if the speed is too fast, the rope will disconnect, stones will be flying out. This is the so-called centrifugal.Centrifugal pump is designed according to this theory, high-speed rotation of the impeller blades rotate driven water, throw water, so as to achieve the purpose of transportation.Good variety of centrifugal pumps, from the use can be divided into civil and industrial pumps; from the transmission medium can be divided into clear water pump, trash pump, corrosion pump and so on.Basic structure centrifugal pumpBasic structure of the centrifugal pump is composed of six parts, namely: impeller, shaft, bearings, seal rings, stuffing box.1 centrifugal impeller is a core component of its speed and high output force, the impeller blade has played a major role in the assembly before the impeller by static test. Impeller on the inside and outside surfaces required to be smooth to reduce flow friction loss.2, pump, also known as the pump casing, which is the main water pump. Play a role in supporting fixed, and with the installation of the bearing bracket connected.3, pump shaft and motor function is connected by coupling, the motor torque transmission impeller, it is the transfer of mechanical energy of the main components.4, the bearing is set on the support shaft in the shaft component, there are two kinds of rolling bearings and plain bearings. Rolling to use butter as lubricant oil to be appropriate is 2 / 3 3 / 4 size too much may have a fever, there are too few sound and heat! Pump bearing structure is transparent to the oil used for lubricants, fuel to the oil level line. Too much oil to be leaking along the shaft and drift *, too little overheated bearings and also burn the accident! Bearing in the pump during operation the maximum temperature of 85 ℃in the general run of 60 degrees, if we should find out the reasons high (whether impurities, oil is black, is water) and timely manner5, sealing ring, also known as leakage reduction ring. Impeller and pump casing of imports over the gap between high-pressure areas cause the pump's water flow through the gap area of low pressure affecting the pump out water, reducing efficiency! Gap is too small will cause the impeller and pump casing friction and wear. In order to increase the return to reduce the internal leakage resistance and delay of the impeller and pump casing life of the pump impeller shell edge and foreign aid junction with sealing ring, sealing the gap remained at 0.25 ~ 1.10mm hydrometer.6, stuffing mainly by the packing, seal ring, filler tube, packing gland, seal tubes. The main function of stuffing is to be closed between the pump casing and shaft gap, not to pump the water does not flow out to not let outside air into the pump. Always maintain the vacuum inside the pump! When the pump and fill the water seal friction depends on the heat pipe to live on the water to seal circle to fill the cooling! To maintain the normal operation of pumps. So check the pump to run during the tour of inspection of the stuffin g is the special attention! About running 600 hours on the packing should be replaced.The working principle of centrifugal pumpImpeller installed inside the pump casing 2 and fastened in the shaft 3, the shaft directly driven by the motor. Central has a liquid pump casing and suction pipe inhaling 4 5 connection. Liquid through the bottom valve 6 and the suction tube into the pump. Pump casing liquid discharge outlet on the discharge pipe 8 and 9 connections. Before starting the pump, the pump is transported shell filled with liquid; starts, starts, the impeller shaft driven by the high-speed rotation, the liquid between the blades must rotate with. Under the action of centrifugal force, the liquid was thrown from the center of the outeredge of the impeller and get energy from the impeller at high speed into the volute pump outer shell. In the spiral case, the fluid flow, gradually as the expansion slowed down in turn part of the kinetic energy into static pressure energy, the final discharge at higher pressure into the pipeline, sent to the need to place. The flow of liquid from the center of the outer edge of the impeller when the impeller center in the formation of a certain vacuum, due to the pressure tank above the liquid level is greater than the pressure at the entrance to the pump, the liquid will be pressed into the impeller in a row. Can be seen, as long as the constantly rotating impeller, the liquid will continue to be sucked and discharged.The phenomenon of gas tieWhen the pump casing to the existence of air, because air density is much smaller than the density of the liquid caused by a smaller centrifugal force. Thus, the tank liquid level above the entrance and the pressure difference between pump sufficient fluid pressure within the tank into the pump, that is not self-priming centrifugal pump, so pump can not transport liquid, such phenomenon is known as "gas tie phenomenon. " In order to pump full of liquid, usually installed in the suction pipe along the bottom of the bottom filter valve, the bottom valve until the valve, the filter is to prevent solid material into the pump impeller damage or impede the normal operation of the pump.The main components of centrifugal pump Main components are impeller, pump casing and shaft seal devices.1 impellerThe role of the impeller is the original motivation of the mechanical energy directly to the liquid, to increase the liquid static pressure energy and kinetic energy to the major increase in static pressure.Impeller are generally 6 to 12 after the curved blade.Impeller are open, semiclosed-type and closed three, as shown in Figure 2-2. Both sides of the blade open impeller without cover, create a simple, easy to clean, suitable for transmission over a large number of suspensions containing materials, inefficient delivery of the liquid pressure is not high; semi-enclosed impeller in the suction side of the non-cover board, while the other side of cover, precipitation, or easily applicable to transport materials containing particles, and lower efficiency; closed impeller, the impeller bladeson both sides of the front cover with high efficiency, suitable for delivery without impurities cleaning liquid. Multi-impeller centrifugal pumps in general for such.Impeller with a single suction and double suction two suction fluid ways.There is a single suction inlet, along with water from both sides for double suction.2 pump shellRole is to impeller enclosed in a certain space for the role by the impeller and the pressure of the fluid inhalation. Multi-spiral-shaped shell made of the pump, so called spiral. As the flow cross-sectional area gradually expanded to throw it around from the impeller speed liquid flow rate decreases, so that part of the kinetic energy is converted to static pressure can be effective. Together not only by the impeller pump casing throw the liquid, is also an energy conversion device.3 seal deviceRole is to prevent the pump shell along the axis of liquid leakage or air leakage into the pump outside the containment.Common seal device has two kinds of packing seal and mechanical seal.General packing coated with oil or graphite Baptist asbestos rope. Mainly by mechanical seal is mounted on the shaft of the ring and fixed on the pump casing static ring relative motion between the end face for the purpose to achieve the seal.Centrifugal flow passage componentsCentrifugal flow passage components are: inhalation chamber, impeller, achamber pressure of three parts. Is the core of the pump impeller chamber, is also part of the core flow. Pump liquid through the impeller on the Power, to increase the energy. Impeller according to the direction of liquid flow is divided into three categories:(1) run-of impeller (centrifugal impeller) and the liquid along the axis perpendicular to the direction of flow impeller.(2) oblique flow impeller (mixed flow impeller) of liquid along the axis tilt of the direction of flow impeller.(3) liquid axial flow impeller and the axis parallel to the direction.Impeller by way of inhalation is divided into two categories:(1) single-suction impeller (the impeller from the suction side of the liquid).(2) double suction impeller (the impeller from both sides of inhalation liquid).Divided into three categories according to the form of impeller cover:(1) closed impeller.(2) open impeller.(3) semi-open impeller.Closed impeller which is widely used, the aforementioned single-suction impeller double suction impeller belong to this form.Type of centrifugal pumpFrist. and, according to the number of categories impeller1, single-stage pump: that is, only one pump impeller.2, multi-stage pump.: In shaft with two or more of the impeller, when the total pump head for the n-of impeller and the resulting head.Second, according to classification of work stress1, low-pressure pump: pressure less than 100 m water column;2, medium pressure pumps: pressure is between 100 to 650 m water column;3, high-pressure pump: the water column pressure is higher than 650 meters.Third, by way of classification of the impeller inlet1, side water pump: also known as single-suction pump, which the impeller is only one intake;2, bilateral water pump: also known as double suction pump, which the impeller has an inlet on both sides. Its single suction pump flow ratio doubled in size, can be approximately regarded as two single-suction impeller placed together back to back.Fourth, according to the form of pump casing combined with joint classification1, horizontal split pumps: the line in the horizontal plane through the center of a combination of open seam.2, the vertically integrated surface pumps: the combination of surface and perpendicular to the axis line.Fifth, according to shaft position to Category1, horizontal pump: pump in the horizontal position.2, vertical pump: pump in the vertical position.Sixth, according to the impeller out of the water pressure out of room to lead the way classification1, volute pumps: water from the impeller out, directly into a spiral shape of the pump shell.2, guide vane pump: water came out from the impeller into the diffuser set it outside, and then proceed to the next level or into the outlet tube.Usually we say that a multi-stage pumps are pumps, impeller means in terms of how much. According to other structural features, which there may be horizontal pumps, vertical integration surface pumps, guide vane pumps, high pressure pump, water pump and so on one side. So according to different, it is called not the same. Also, according to use can also be classified as oil pump, water pump, condensate pump, ash pump, circulating water pumps, etc.Classification of the characteristics of centrifugal typeBy inhalation of a single suction pump means flow of liquid from the side of the impeller, there is the axial forceDouble suction pump liquid into the impeller from both sides, there is no axial force, the flow rate is almost double than single-suction pumps Series single-stage pump according to only one impeller shaftMulti-stage pump with a pump to upload two or more impellers, the liquid flow through each impeller in turn, more series, the higher lift Horizontal shaft by horizontal shaft orientationVertical shaft perpendicular to the horizontal planBy housing type pump housing by sub-vertical plane with the shaft portion between the segments and segment connections with long bolts Open-pump in the shell line in the plane through the center of SplitSpiral volute pump with pressurized water pump room, such as the common end-suction cantilever centrifugal pumpTurbine guide vane pump with pressurized water chamber of the pumpSpecial StructurePipeline pumps as part of pipeline, pipeline installation, no need to changeSubmersible pumps and motors made of one immersed in waterImmersed in liquid pump liquid pumpsShielding pump impeller and the motor rotor together as one and the same within a sealed shell without fully sealed, leak-free pumps areIn addition to magnetic pump inlet and outlet, the pump fully closed, the pump and motor coupling magnets can attract each other and driven by Special StructurePipeline pumps as part of pipeline, pipeline installation, no need to changeSubmersible pumps and motors made of one immersed in waterImmersed in liquid pump liquid pumpsShielding pump impeller and the motor rotor together as one and the same within a sealed shell without fully sealed, leak-free pumps areIn addition to magnetic pump inlet and outlet, the pump fully closed, the pump and motor coupling magnets can attract each other and driven by Self-priming pumps do not start filling liquidHigh-speed pump from the tank to pump speed to increase the growth rate, the general speed up 10000r/min above can also be called part of the tangential flow pump or booster pumpVertical Barrel Pump imports and exports over the same height in the upper part, there inside and outside the two-shell, internal shell from the rotor, stator, etc. component, shell body for the import diversion channel, the liquid from the lower part of inhalationMany different types of centrifugal pump, a common classification of the following ways1, by way of sub-suction impeller: single suction centrifugal double suction centrifugal pump;2, the number of points by the impeller: a single-stage centrifugalmulti-stage centrifugal pump;3 points by impeller structure: semi-open impeller centrifugal pumps with open impeller centrifugal pump closed impeller centrifugal pump;4 points by working pressure: low pressure centrifugal pump inhigh-pressure centrifugal pump;5 points by shaft position: horizontal centrifugal side of vertical centrifugal pumps.SG life to pumps, pump life, residential water pumps, life, water supply and drainage equipment, according to IS, IR-based performance parameters and vertical centrifugal pump's unique combination of design structure, and in strict accordance with ISO2858 requirements set wine production, with domestic water quality designed with the model, is the ideal next-generation horizontal pump. The product shall be used carbide mechanical seal. Applications:ISW-type pumps suitable for industrial and urban water supply and drainage, such as the pressurized water supply in high-rise buildings, garden irrigation, firebooster, long-distance transportation, HVAC refrigeration cycle, bathroom, and Equipment for Pressure, temperature does not exceed 85 ℃. ISWR pump widely used in: metallurgy, chemical, textile, paper, shops, restaurants and guest pressurized boiler heat the water, transport, and urban heating systems, SGWR type using the temperature does not exceed 120 ℃.Pipeline pump installation key technologies: the suction pump used to install a high degree ofFirst, the key to install the technology of centrifugal pumpInstallation of pipeline centrifugal pump installation key is to determine the height of the suction. The high water means the water pump impeller to the center line of the vertical distance, it allows a high degree of suction on the vacuum can not be mixed up, pump product specifications or nameplate allows a high degree of vacuum suction on the pump inlet section refers to the vacuum value, it is a standard atmospheric pressure, water temperature under 20 ℃, tested and determined to come by. It does not take into account the water flow after suction pipe supporting position. The pump mounting height should be allowed to smoke on a high vacuum suction pipe loss deduction after the head, the rest of that part of the value, it is highly absorbent to overcome the actual terrain. Pump installation height can not exceed the calculated value, otherwise, would be no water to pump. In addition, the effect size calculated is the resistance to water absorption pipe head loss, therefore, should use the shortest possible piping arrangements, and elbows and other fittings installed as little as possible, also be appropriately equipped with larger diameter water mains to reduce the internal velocity.It should be noted that the pipeline centrifugal pump installation site elevation and the water temperature is different from the experimental conditions, such as local elevation of 300 meters or pumping the water temperature exceeds 20 ℃, the calculated values to be amended. That is, different elevation Department of atmospheric pressure and temperature higher than 20 ℃when the saturated steam pressure. However, the water temperature is 20 ℃below the saturated vapor pressure is negligible.From the pipe installation technology, water absorbing pipes require strict sealing, can not leak, leakage, otherwise it will damage the intake pump vacuum to pump out the water less serious or even no water to. Therefore, to carefully work out the pipe interface, ensuring the construction quality of the connection pipe.Second, pump installation height calculation HgAllows a high degree of vacuum suction on the pump Hs is the pressure p1 at the entrance to the maximum allowable vacuum.The actual height to allow the vacuum suction on the Hs values are not calculated according to the value, but by the pump manufacturer experimental determination of the value that is attached to the pump samples for user reference. Bit should be noted that pump the sample values are given in Hs with water as the working medium, and the operating conditions of 20 ℃and pressure of 1.013 ×105Pa when the value, when the operating conditions and the working medium is not the same time, the need for conversion.1 transport water, but the operating conditions and experimental conditions, Ke Yi-type conversion underHs1 = Hs + Ha-10.33 - Hυ-0.242 transport other liquid when the liquid is transferred and the villain and the experimental conditions, conditions are not the same time, the need fortwo-step conversion: the first step according to the type will be detected sample pump Hs1; second step according to the following formula will be converted into H Hs1 s2 cavitation margin ΔhFor the pump, when the installation height calculation used to calculate the cavitation margin Δh, which pumps the liquid to allow the v acuum suction, which allows the installation of the pump height in meters. Used by the oil pump cavitation margin Δh che ck sample taken, its value is also measured with 20 ℃water for. If the delivery of other fluids, should also be calibrated, detailed investigation of the books.Suction = standard atmospheric pressure (10.33 m) - NPSH - safe level (0.5 m)Standard atmospheric pressure to high vacuum pressure pipe 10.33 meters.Pump worksKey Parts of centrifugal pump with suction chamber, the impeller and the pressurized water chamber. Suction chamber is located in front of the impeller inlet, impeller play the lead role of the liquid; pressurized water main spiral chamber pressurized water chamber (spiral type), guide vanes and guide vanes are three forms of space; pump impeller is the most important element of work is the heart of flow parts, impeller blades from the cover and intermediate composition.Pump before work, first pump filled with liquid, and then start the pump, impeller rotation speed, rotating impeller blades driven liquid, liquid to the impeller rotational inertia when rely on flow to the outer edge, while the impeller from the suction chamber inhalation liquid, this process, the liquid flow around the impeller blades, in the liquid flow around the role of sport in alift on the blade, and this in turn leaves a lift equal and opposite force on the liquid, the force acting on the fluid, so that the fluid flow of energy and impeller, then the kinetic energy and pressure energy of liquid will increase.Rotating impeller centrifugal pump relies on the role of fluid mechanical energy of the original motivation delivered to the liquid. As the role of centrifugal flow of liquid from the impeller import export process, its speed can be increased and pressure to have been discharged from the impeller through the pressure of the liquid rooms, most of the speed can be converted to pressure energy, and transportation along the discharge pipe out, this time, the impeller discharges the liquid inlet formed by vacuum or low pressure, suction pool of liquid in the surface pressure (atmospheric pressure) under the action of being pressed into the impeller of imports, thus, rotating with the impeller on the continuous to suction and discharge liquid.离心泵离心的概念离心其实是物体惯性的表现，比如雨伞上的水滴，当雨伞缓慢转动时，水滴会跟随雨伞转动，这是因为雨伞与水滴的摩擦力做为给水滴的向心力使然。