Close contact with the market has opened up new fields of application. The two main parts of the pump are the impeller and the diffuser. Mounting pad accessory drives a splined shaft is recommended on applications where the pump shaft is coupled directly into a transmission or gearbox. Why centrifugal pumps break shafts and how to prevent it. Axial flow pumps are high flow, low pressure pumps which lift fluid in a direction parallel to the impeller shaft. Design of centrifugal pump pressure gauge pressure measuring instruments design of centrifugal pump leave a reply cancel reply. Shaft materials, shaft layout, torque transmission, calculating static stresses, dynamic stresses and fatigue, determining critical stress locations, deflection, critical speed a shaft is a mechanical part that normally has a circular crosssection. The causes of such failure could be classified based on a faulty design or misapplication of the materials. Any system design that requires hydraulic force to operate. The second gear, being the driven gear, is also shrinkfitted on a precisionground and polished driven shaft. The pump shaft is the central component of a centrifugal pump rotor and carries the impellers, the shaft sleeves e. The possibility of interference between the shaft and. Pull total torque out of shaft side torque, and handle head torque less than 90 nm setting of pressure and the displacement upon shipment p.
Vibration when a shaft is spinning, particularly at higher speeds, vibration within the pumping equipment becomes a. The basic shaft design will address torque as the primary dynamic because torque is the most important design element speed and power are integral factors of torque. Sealing systems for pumpssealing systems for pumps part ii presented by. As the pump shaft rotates, the rotating face rotates against the stationary. It transmits the rotary motion from the motor to the impellers of the pump stage. It provides an axis of rotation for a variety of mechanical components.
Running volutestyle pumps at a lower capacity than the manufacturer recommends can put lateral stress on the shaft of the pump, increasing wearandtear on the seals and bearings, and on the shaft itself. S0 design requirements s10 design methods the design rules presented in this section are provided as guidance to the designer of pump shafts. Capability for handling entrained gas is an important design consideration for. Pdf design, production and testing of a single stage centrifugal. The impeller is the device that rotates in the liquid and is usually contained inside a volute, or casing. This allows rotating elements of the pump to be dismantled. Pumps and pumping system bureau of energy efficiency 1 syllabus pumps and pumping system. Centrifugal pump casings are fabricated to accept a given maximum impeller diameter allowing for a hydraulic clearance to facilitate fluid motion to the pump discharge point.
Centrifugal pump mechanical design, analysis, and testing author. Split casing design allows pump to be splitted axially. They include suggestions for the loads to be considered. The second step in the design sequence is the mechanical design of the mixer components. Pdf centrifugal pump handbook, third edition sulzer. The diagram shows the main parts of the centrifugal pump. Pressure seal at shaft connection is ensured by packing seal. These bars, however, are manufactured to a higher standard than common steel bars. However all pump systems are different, in some systems the friction energy may represent 100% of the pump s energy, this is what makes pump systems interesting, there is a million and one applications for them. Pump configuration pump shaft radial support options pump series description a 338 series d 387400 series s 538 series g 540 series h 562 series j 675 series l 725 series m 862 series n 950 series p 1125 series intake types. Pump housing impeller packing leakage shaft process fluid.
Cavitation may be an important design consideration when liquids are involved if the pressure at any point within the flow is reduced to vapor pressure. What makes a pump shaft quality stainless steel bar. The rotor shaft drives the pump through a crank mechanism. This new edition of the centrifugal pump handbook takes full account of the recent progress that has been made in pump construction and technology. For a shaft of two diameters d 1 under the seal sleeve and. Retaining rings, which are installed in grooves provided on the shaft, ensure that the gears will not move axially, and a key. For a shaft of two diameters d 1 under the seal sleeve and d 2 between the bearings see figure 2, the shaft stiffness. In an axial flow pump, the impeller pushes the liquid in a direction parallel to the pump shaft. The blue pump curve represents either of these options. By this design axial load generated within pump, get balanced without need for balance disc or impeller balance holes. The design engineer can figure the weights of the shaft and the impeller. Tkv vertical pump tkv pumps are vertical, centrifugal multistage pumps connected to the drive generally an electric motor by flexible coupling. However all pump systems are different, in some systems the friction energy may represent 100% of the pumps energy, this is what makes pump systems interesting, there is a million and one applications for them.
Home pump expert advice why centrifugal pumps break shafts and how to prevent it. The pump shaft is coupled to the motor shaft through the intake and seal shafts. Fl floater design c compression, fixedimpeller design. Northern pumps commonly operate at standard motor speeds of 1150, 1750, and 3600. Design of a centrifugal pump the engineering concepts. Care must be taken when selecting the shaft material for each application. Reda electric submersible pump systems technology catalog. Find bending moments from gears, pulleys, or sprockets that are transmitting loads to or from other devices. The speed of the pump can be reduced or the existing impeller can be trimmed or new lower size impeller. Tutorial centrifugal pump systems by jacques chaurette p. This article is part of pumps 101, an elevenpart series of articles designed as an introduction to the fundamentals of centrifugal pump design, selection, and application. Jul 17, 2017 the pump shaft is coupled to the motor shaft through the intake and seal shafts. The impeller is typically connected to an electric motor which provides the energy to be. But there are other simpler options rather than replacing the pump.
Dec 17, 2011 these designs allow the pump shaft to pass through the hollow motor shaft, which simplifies the coupling process for pump shafts that must support the heavy water column associated with a deep well. Based on a modular design system, the ecpj pump provides dependable performance while offering maximum mechanical and hydraulic design flexibility. The calculations for shaft diameter are not quite as straightforward for a vertical hollow shaft motor. Impeller, which is the only moving part, is attached to a shaft and driven by a.
A practical guide to shaft alignment plant services. The pump shaft transmits the drive torque to the impellers of centrifugal pumps or to the displacement elements of rotary positive displacement pumps. In fact, virtually all modern vehicles use fluid power, and new vehicles and markets are appearing as. The designed pump delivers 100 ls flow rate against a head of 24 m. Fully compliant with iso 709api 610 vs4, latest edition, each ecpj pump can be custom.
Most pump manufacturers and repairers recommend that when repairing damaged pumps, bearings should always be replaced irrespective of apparent condition, since it is easy to miss minor damage to the bearing. To provide a certain amount of power to the liquid a larger amount of power must be provided to the pump shaft to overcome inherent losses. Pumps may be classified in two general types, dynamic and positive displacement. Pump, intake, and gashandling device nomenclature stage construction designation description fl floater design c compression, fixedimpeller design cr compression ring, fixedimpeller design compression design greatly improves reliability and extends the operating range of the esp compared with. The possibility of interference between the shaft and transmission splines, due. However, this occurs best at the manufacturers recommended capacity.
This line of best fit was converted into the formula. Fundamentals of fluid mechanics chapter 12 pumps and turbines. The impeller of a typical axial flow pump and the flow through a radial flow pump are shown in figure 7. The loop is equipped with instrumentation to measure temperature, pressure, flow rate, pump speed, pump shaft horsepower, shaft torque, and shaft axial. The shaft toque the torque that the shaft applies to the rotor and. Details as to considerations of pipe systems are given in chapter 6, design of pumps. Pump shaft of electric submersible pumps selection criteria.
Sealing systems for pumpssealing systems for pumps part i. Design, production and testing of a single stage centrifugal pump. Special attention was given to produce a manual that is interesting and informative for everybody, from the competent engineer to. Determine torque in shafts from gears, pulleys, sprockets, clutches, and couplings. The shaft passes through the pump casing and out through the stuffing box portion of the casing through which the shaft extends and where seal or packing is placed. An impeller a volute or diffuser style casing a shaft shaft sleeves bearings a sealing arrangement these parts can be subdivided into the wet end and the mechanical end. Pump shafts are stainless steel bars that can vary in shape depending on the pump application. This shaft extends outside the pump to permit coupling to an external prime mover. There are several cranks to support the bearings and seals. Basic pump parameters and the affinity laws instructor.
Each liquid possesses diverse characteristics that may influence not only the choice of the pump, but also its configuration such as the type of the mechanical seal or the motor. Booster pumping filter backwash membrane feed chemical feed raw water wastewater treatment nonclog impellers. Compact design that enables greater flexibility and cost. There are a few components that virtually every centrifugal pump has in common. Compare combined stresses to suitable allowable stresses. A comparative study on centrifugal pump designs and two. Shaft size should take care of the torque and bending moment, should avoid. Removal and refitting in itself can cause bearing damage. Fundamentals of fluid mechanics chapter 12 pumps and. The shaft toque the torque that the shaft applies to the rotor and the rotation of the rotor are in the same direction, energy is transferred from the shaft to the rotor and from the rotor to the fluid. Pump leakage atmosphere housing shaft leakage di l t process fluid perpendicular to. Api 610 11th edition annex k gives a standardised method for calculating an overhung pump shaft flexibility index that can act as a baseline for comparing shaft flexibility between different pump designs. Since it is not practical to consider all these variables in a reasonably useful alignment. In household systems, friction can be a greater proportion of the pump energy.
In this frame, a nonclog type submersible pump that is capable of handling solids, up to a diameter of 80 mm is aimed to be designed. Pump cover, impeller, pump housing lantern, shaft and motor impeller onepart. Centrifugal pump mechanical design, analysis, and testing. The impeller is mounted on the pump shaft and within the pumps casing. Using a logarithmic scale, a line of best fit was found that could be used to evaluate a reliable shaft design for any pump. Mixed flow pumps are medium flow, medium pressure pumps which push fluid out away from the pump shaft at an angle greater than 90. Before starting up the pump, fill the pump case with clean hydraulic operating fluid. Clockwise or counter clockwise model code gear design pg displacement xxxx style a rotation x frame 511 pump p shaft a1 shaft end cover h2 seal material n side inlet xx side outlet xx rear outlet b1 rear inlet b1. Centrifugal pump problems 5 overview of pump problems typically found on centrifugal pumps. Elevated requirements come from a variety of factors.
Design and modification of shaft for an evaporation section. Axial flow pumps are sometimes called propeller pumps because they operate essentially the same as the propeller of a boat. The shaft of reciprocating positive displacement pumps takes the shape of a crankshaft or a camshaft. The main parts of a centrifugal pump intro to pumps. Cavitation may be an important design consideration when liquids are involved if. Centrifugal pumps are designed for optimal operation in their design point, i.
Alternative design methods may be used based on the pump manu. Index introduction page 1 chapteri,relationbetweenperipheralvelocity andhead 2 chapterii,design pump works by converting the energy of a spinning impeller to increase the velocity of a liquid. The shafts purpose is to transmit the rotational motion and power torque from the driver to the pump shaft components, mainly the impellers. Over the past twenty years, the application of hydraulics in agricultural, construction and materials handling vehicles has. Index introduction page 1 chapteri,relationbetweenperipheralvelocity andhead 2 chapterii,design api std. Pdf fatigue failure analysis of a centrifugal pump shaft. This allows rotating elements of the pump to be dismantled or fixed without disturbing suction and discharge flange connections, by just opening the casing cover. To get the most out of intro to pumps check out the full series. The performance of the pump was numerically optimized on a twodimensional centrifugal pump impeller to. In order to keep the liquid from leaking out of the casings.
The fundamental approach is straightforward, design for power torque and speed, then shaft loads, and finally mixer dynamics. Shaft stress calculations shaft 1 diameter38 material. Alignment and drive of line shaft is ensured by bush bearing located in pump casing and by the column pipe joints. Approximate upper limit of pressure and capacity by pump class. This paper presents a collection of pump shaft failures that have been encountered during the consulting activities at the university of the witwatersrand and the plant infrastructure and pipelines centre at the council for scientific and industrial research csir. Shaft design objectives compute forces acting on shafts from gears, pulleys, and sprockets. What we now need is a new pump which will operate with its best efficiency point at c. Sealing systems for pumpssealing systems for pumps.
The hydraulic efficiency is a measure of these losses and is the comparison of power input to the pump shaft to that of the poser transferred to the liquid. Impellers are manufactured in many styles each with its own. The importance of shaft stiffness in api 610 11th edition. Before starting up the pump, fill the pump case with clean hydraulic operating fluid through the lubrication port 39 cu in 2.
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