Shafts are always made to have circular crosssection and could be either solid or hollow. Shortcut method deflection of beam mechanicalcivil. Shaft stress can usually be handled by using better materials, and is a lesser problem. The calculus of the mixing rotating devices shafts based on the energonics method 109 on each mixer i i 1,n0 mounted on the shaft, a bending radial force acts either in the xoy plan being notedfy,i, or in the xoz plan being noted fz,i, depending on the mixer blades orientation as function of the chosen coordinate system. Agitator shaft length should be calculated on which basis. Complete range of materials available, carbon steel, stainless steel, and high corrosion resistant alloys hastelloy, titanium, tantalum, etc.
A practical guide to shaft alignment plant services. Review on design of agitator 1akash j patil, 2sachin b rajude 3mayur s thok, 4ajit r pawar be student. Agitator shaft deflection bearing mechanical gear scribd. Never expose the agitator to undue vibrations or shocks. Detection of failure mode of pressure vessel agitator due to.
When an agitator is supplied with a shaft seal for closed stirred tank applications or when stirred tank internals heating coils, draft tube, limit ring, etc. Figure 2 stepped shaft showing relationship of shaft deflection and wear for. Review on design of agitator to optimize its performance. Student 2professor 1,2department of mechanical engineering 1,2msss cet, jalna abstractmixing is very important operation in any process industry. Never lift the agitator using the extension shaft as a lift point. Process engineering mind mixer mechanical design chemical.
Deflection and critical speed are related of course, so shaft stiffness is of primary concern. It is true that flexible couplings are designed to take misalignment, typically up to 400 mils or more radial offset of the shafts. The agitator was driven thru a right angle gearbox via a motor operating at 1,780. However, these thresholds are often exceeded in practical application. The loads are active and are transmitted from the impeller blades to the agitator shaft. Extra capacity reducer shaft due to a large crosssection, the lowspeed shaft inside the drive minimizes gear misalignment and deflection. The result is ultimate fatigue failure of the gearbox shaft.
Pdf understanding the mechanisms of shaft deflection in. Feb 27, 2019 in this video, i show how to set up define an ansys mechanical model and solve for the deflections of a stepped shaft subjected to an intermediate load. Finite element analysis fea used to calculate critical speed and shaft deflection. The agitator shaft assembly is used in all kitchenaid stand mixers.
In this study, the failure fracture of an agitator shaft with a circumferential notch was selected. Agitator should be designed to operate at less than 70% of the critical speed. Redesign and structural analysis of agitator shaft for. Bending moment is the hydraulic force fh acting on a shaft at a length away from the bearings perpendicular to the axis of rotation.
Shaft deflection, runout, vibration, and axial motion chapter d4 page 4 contact kalsi engineering search this handbook bearing internal and mounting clearances influence shaft runout side loads cause the shaft to articulate within mounting clearances, resulting in lateral shaft deflection at the location of the rotary seal. I am asking this because on low level alarm 20 % of tank, agitator is not getting immersed in liquid resulting in frequent damage to bearing due to vibration so we have changed alarm value to 50% instead of 20%. Double lip seals on the drive shaft prevents oil loss or the infiltration of contaminants. Failure of agitator shaft leads to breakdown of whole plant. Design and analysis of agitator blade of pressure vessel. Bending moment causes the shaft to bend away from the central rotational axis and is critical to determine the shaft material. During a starting up, the shaft has to withstand key words.
Agitation free download as powerpoint presentation. The deflection due to each load p contact pressure acting independently is given. Shaft design for industrial tank agitators thomasnet. Agitator output speed, shaft diameter and extension, impeller. Shaft and bearing calculations 121 shaft and bearing calculations gert hallgren itt flygt ab abstract. Another aspect to consider when you are selecting your seal is radial shaft deflection.
Examples of lateral shaft displacement are dynamic runout, deflection, and vibration. Tom 05 vibration critical speed or whirling of shaft youtube. Installation, operation and maintenance manual mrd and. Design and implementation of differential agitators to maximize agitating performance saeed asiri king abdulaziz university, 21589, jeddah, p.
Even minor shaft deflection causes loss of sealing function and increased wear. The reactor agitators type hwln are the most powerful agitators compared to the others in ekatos product range. Design stresses in shafts august 15, 2007 23 find the torsion in the shaft. The 7800 vessel seal family was originally developed for the north american market. Large sized agitators with a drive power of up to 3,500 kw, shaft lengths of more than 15 m, as well as 500 mm shaft diameters, have already been supplied. Installation, operation and maintenance manual mrd and mrp. The other major analysis in the design is the vibration characteristic of the mixer, especially the shaft since system harmonics can lead to amplification of any of the major forces. In any case, gear reducers, shafts, impeller blades and other basic components should be chosen to match the maximum motor load.
One of the major parameter to increase the overall performance of. Adaptations to interim or metricsized shafts are available on request. Btn agitators installation, operation maintenance manual. Installation dimensions according to din 288 part 1 are possible.
If the operating conditions are under high pressure or high temperature, the agitator must be equipped with a sealing system to keep tightened the inside of the tank when the shaft is crossing it. Agitator shaft deflection free download as pdf file. Complete range of agitator mechanical seals available from top seal manufacturers including chesterton, john crane and flowserve. The agitator is subjected to vibration due to multiaxial forces resulting from bending and torsional loading imposed by the mixing operation. The differential agitator is an electro mechanic set consists of. This research is to design and implement a new kind of agitators called differential agitator. Figure 2 stepped shaft showing relationship of shaft deflection. Lock out the mixer or agitator motor and valves to and from the vessel and seal. In general, the force exerted by the downsweep side of the agitator is greater than that of the upsweep.
Model 20 ht and gt agitators reliable performance and value. Use plant vessel entry procedure if it is necessary to enter the vessel. Shaft deflection, runout, vibration, and axial motion. The main forces are torque, bending loads, and thrust. Agitator design and selection standard engineers vineet. The extension shaft is also designed to minimize deflection for superior seal life. This will be the case unless the shaft is overloaded or damaged. In this video how to remember all the importants formulas of slope and deflection is explained by using a simple algorithm, which will help you to remember it till your lifetimeif you feel. Determine torque in shafts from gears, pulleys, sprockets, clutches, and couplings. Therefore, knowledge and understanding of the variety of factors that.
Design and analysis of conical curved agitator for medium. Shaft is supported in selfaligning ball bearings and gears are both 10 pitch, 40 tooth, 20 spur gears. To do this, it is necessary to know the local viscosity, which may vary with shear rate. Mixing solutions web strategy and design by advonet communications and ampedpixel media.
Shaft shown drives a gear set that is transmitting 5 hp at 1750 rpm. Jan 18, 2009 design of shaft length of agitator posted in industrial professionals. Centrifugal forces are also present while the shaft is rotating and agitator is out of balance. Detection of failure mode of pressure vessel agitator due. Apr 18, 2006 mind mixer mechanical design while most mixers can provide a long service life for instance, some are still operating after more than 30 years mechanical problems can shorten life or even break parts. A crack starts at a stress concentration from a keyway or a sharp radius, or, in rare cases, from a material impurity. Find bending moments from gears, pulleys, or sprockets that are transmitting loads to or from other devices. The flat beater, dough hook, and wire whip couple with this part to allow for mixing. Straight shafts are commonest to be used for power transmission. During starting, the shaft must be capable of resisting 1. Drive features internal shafting lowspeed internal shaft short bearing span reduces deflection and harmful gear misalignment lowspeed shafts have extra large.
Such shafts are commonly designed as stepped cylindrical bars, that is, they have various diameters along their. Propeller shaft tolerance tables aqualoy 17, 19, 22 and 22hs for new product home up aqualoy 17 propeller shaft aqualoy 19 propeller shaft aqualoy 22 and 22 hs propeller shaft 316 stainless steel propeller shaft 174 stainless steel propeller. If a std is employed, it is possible to change seals with the vessel loaded and under pressure shaft must be stationary. Vertical shaft deflection mechanical engineering general. Complex designs with auxiliary bearings do exist, which prevent radial deflection at the seal between the lips and the shaft. The agitator mounting plate fixed to the tank is constructed from stainless steel and a vring shaft sealing system is used.
It was a 3200 mm long, 50 mm 2 diameter, schedule 40, 316 stainless steel pipe with the 1. In this video, i show how to set up define an ansys mechanical model and solve for the deflections of a stepped shaft subjected to an intermediate load. Our core business was and is the technical design and production. Alwayssupport the shaft adequately, to protect shaft and bearings. The nbi series is a range of vertical agitators with directcoupled speed reduction gearbox. For side insert agitators, there is really no substitute for shaft diameter, since deflection is critical to packing, and even more to mechanical seal performance. This kitchenaid part comes directly from the manufacture. Maximum radial shaft deflection for agitators is defined in din 28161. Tubular applications with shaft lengths exceeding 60 feet. Design specification of the motor is then determined by. The break was dead in the middle between the two endsupporting roller bearings. We then calculate deflection, due to this force and impeller with hub acting at the end of shaft via.
Figure 1 shows a typical vertical shaft hydroelectric unit as found in bureau of reclamation powerplants. Food for thought you wanted to stir things up but, your mixing gave only agitation. Vertical shaft hydrounits description to better understand the alignment process, it is important to understand the basic construction of vertical shaft hydrounits. Still process overloads can occur and may damage the motor or shorten the life of other components. Unlike static deflection which bends the shaft downward, dynamic deflection forces the axis of the shaft upwards towards the upsweep side of the mixer. Review on design of agitator to optimize its performance rahul h. It also has an oversized output shaft, which reduces gear deflection and noise, with a true. Tubular shafts provide a stiff, light weight design which may be more cost effective in longer shaft designs. The agitator disperses a powder into water until it dissolves. The importance of shaft stiffness in api 610 11th edition. Lower shaft through vessel nozzle into tank and support with approximately 8 inches of shaft extending above the vessel flange.
Years of field experience and laboratory testing, together with advanced calculations, form the basis for development of flygt methods and computer programs used to analyze and dimension the rotating system of a pump or mixer. The screw conveyor auger shaft was broken in half right at the center. Shaft design objectives compute forces acting on shafts from gears, pulleys, and sprockets. In order to rotate the agitator at the required speed, it is attached to a shaft. Dynamic shaft deflection occurs when the mixer is operating. Agitator shaft, bending stress, impeller, reactor pressure vessel, torsional stress. The shafts are classified as straight, cranked, flexible or articulated. In this article, learn about all the mechanical problems that may befall your mixing equipment. Design of shaft length of agitator industrial professionals. Mixer agitator bending moment and shaft deflection.
Whether a kalsi seal is being used for high or low pressure. Consider adding bracing under the motor base to eliminate deflection at 2x motor speed. Castiglianos theorem, dummy loads, heaviside step functions and numerical integration. Agitator design and agitator systems about us we have figured it out stelzer ruhrtechnik is one of the leading companies in agitation technology and a soughtafter solutions partner for projectspecific process technology solutions. Compare combined stresses to suitable allowable stresses. I have an agitator that bolts to the center nozzle on the top head of a tank. The agitator must be equipped with such a tough sealing system, when the operating conditions are under high pressure or high. Mechanical agitator power requirements for liquid batches.
Mixer agitator bending moment and shaft deflection tuesday, september 06, 2016 bending moment is the hydraulic force fh acting on a shaft at a length away from the bearings perpendicular to the axis of rotation. Rotating shafts under bending stress accendo reliability. The speed of the agitator shaft below the red uc ti o ng ab x sh l f than 30 to 40 rpm maximum. Shaft deflection, runout, vibration, and axial motion kalsi. Design and implementation of differential agitators to. The dynamic forces of rotation, which act on drive shafts, of course, also increase with rotational speed. Figure 1 illustrates the forces acting on the impeller and shaft configuration. Shaft deflection, runout, vibration, and axial motion kalsi seals. An agitator is composed of a drive device, a guiding system of the shaft, a shaft and impellers.
Shaft deflection, runout, vibration, and axial motion chapter d4 page 4 contact kalsi engineering search this handbook bearing internal and mounting clearances influence shaft runout side loads cause the shaft to articulate within mounting clearances, resulting in lateral shaft deflection at. Therefore, all measurements follow imperial units, and standard designs are available for inchsized agitator shafts from 1. The burgmann seccomix is the ideal choice for these applications. The approach of metzner and otto 4 can often be used to predict local shear rate.