Mechanical Conveyors Selection And Operation Pdf To Jpg
KamaqalTo calculate the torque required you first need to calculate the inertia of the 15m belt dryer conveyor and anything that is sat on the conveyor when the whole thing starts up ie from zero speed to its final speed.The formula for that is T= I.α where I is the rotational inertia of the system and α is the angular acceleration of the rollers and mass on the conveyor.What 3DDave was trying to tell you was that if you look on your existing motor nameplate and gearbox nameplates the information there would help you calculate this torque figure. RE: Gear Box selection, Torque Calculation (Aerospace) 6 Apr 15 01:31.
Your motor output will likely be the limiting factor with regards to torque in the drivetrain. Based on your OP it sounds like you have an existing motor that is capable of driving the system, so why not use that motor's characteristics to size your gear drives?Also, a speed reduction ratio of 1450/0.02 is extremely high. Just what are the criteria for your redesigned drivetrain? Do you expect to get this speed reduction from a single gearbox? RE: Gear Box selection, Torque Calculation (Aerospace) 6 Apr 15 02:13. My favorite extreme reduction scheme: Machine with Concrete - Arthur GansonIt's not clear what part is running at.02 RPM. Is it a drive roller or the entire belt?Also it isn't clear what the goal is.
Without a goal it sounds more like a new design with incomplete constraints than a change to an existing one. If one is moving material, power, not torque, is the primary consideration. This includes the energy required to accelerate material that drops on the belt and friction in the bearings and losses in flexing of the belt. RE: Gear Box selection, Torque Calculation (Aerospace) 6 Apr 15 02:56.
Flat belt drive in the machine shop at theA belt is a loop of flexible material used to link two or more rotating mechanically, most often parallel. Belts may be used as a source of motion, to efficiently or to track relative movement. Belts are looped over and may have a twist between the pulleys, and the shafts need not be parallel.In a two pulley system, the belt can either drive the pulleys normally in one direction (the same if on parallel shafts), or the belt may be crossed, so that the direction of the driven shaft is reversed (the opposite direction to the driver if on parallel shafts). As a source of motion, a is one application where the belt is adapted to carry a load continuously between two points.
The belt drive can also be used to change the speed of rotation, either up or down, by using different sized pulleys. A small section of a wide flat belt made of layers of leather with the fastener on one end, shown in an exhibit at the inFlat belts were widely used in the 19th and early 20th centuries in to transmit power in factories. They were also used in countless, and applications, such as, for filling or, water (for, mines, or farm fields),.
Flat belts are still used today, although not nearly as much as in the line-shaft era. The flat belt is a simple system of power transmission that was well suited for its day.
It can deliver high power at high speeds (500 hp at 10,000 ft/min, or 373 kW at 51 m/s), in cases of wide belts and large pulleys. But these wide-belt-large-pulley drives are bulky, consuming lots of space while requiring high tension, leading to high loads, and are poorly suited to close-centers applications, so V-belts have mainly replaced flat belts for short-distance power transmission; and longer-distance power transmission is typically no longer done with belts at all. For example, factory machines now tend to have individual electric motors.Because flat belts tend to climb towards the higher side of the pulley, pulleys were made with a slightly convex or 'crowned' surface (rather than flat) to allow the belt to self-center as it runs. Flat belts also tend to slip on the pulley face when heavy loads are applied, and many proprietary were available that could be applied to the belts to increase friction, and so power transmission.Flat belts were traditionally made of leather or fabric. Today most are made of rubber or synthetic polymers. Grip of leather belts is often better if they are assembled with the hair side (outer side) of the leather against the pulley, although some belts are instead given a half-twist before joining the ends (forming a ), so that wear can be evenly distributed on both sides of the belt.
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Belts ends are joined by lacing the ends together with leather thonging (the oldest of the methods),steel comb fasteners and/or lacing,or by gluing or welding (in the case of polyurethane or polyester). Flat belts were traditionally jointed, and still usually are, but they can also be made with endless construction.Rope drives In the mid 19th century, British millwrights discovered that multi-grooved pulleys connected by outperformed flat pulleys connected by leather belts. Were occasionally used, but, and rope saw the widest use. Typically, the rope connecting two pulleys with multiple V-grooves was spliced into a single loop that traveled along a path before being returned to its starting position by an that also served to maintain the tension on the rope. Sometimes, a single rope was used to transfer power from one multiple-groove drive pulley to several single- or multiple-groove driven pulleys in this way.In general, as with flat belts, rope drives were used for connections from to the and of mills, and sometimes from line shafts to driven machinery. Unlike leather belts, however, rope drives were sometimes used to transmit power over relatively long distances. Over long distances, intermediate sheaves were used to support the 'flying rope', and in the late 19th century, this was considered quite efficient.
Round belts Round belts are a circular cross section belt designed to run in a pulley with a 60 degree V-groove. Round grooves are only suitable for idler pulleys that guide the belt, or when (soft) O-ring type belts are used. The V-groove transmits torque through a wedging action, thus increasing friction. Nevertheless, round belts are for use in relatively low situations only and may be purchased in various lengths or cut to length and joined, either by a staple, a metallic connector (in the case of hollow plastic), gluing or welding (in the case of ). Early utilized a leather belt, joined either by a metal staple or glued, to great effect.Spring belts. A two-stage transmission using spring belts on a toy vehicleSpring belts are similar to rope or round belts but consist of a long steel helical spring. They are commonly found on toy or small model engines, typically steam engines driving other toys or models or providing a transmission between the crankshaft and other parts of a vehicle.
The main advantage over rubber or other elastic belts is that they last much longer under poorly controlled operating conditions. The distance between the pulleys is also less critical. Their main disadvantage is that slippage is more likely due to the lower coefficient of friction. The ends of a spring belt can be joined either by bending the last turn of the helix at each end by 90 degrees to form hooks, or by reducing the diameter of the last few turns at one end so that it 'screws' into the other end.V belts.
A multiple-V-belt drive on anV belts (also style V-belts, vee belts, or, less commonly, wedge rope) solved the slippage and alignment problem. It is now the basic belt for power transmission. They provide the best combination of traction, speed of movement, load of the bearings, and long service life. They are generally endless, and their general cross-section shape is roughly (hence the name 'V'). The 'V' shape of the belt tracks in a mating groove in the (or sheave), with the result that the belt cannot slip off.
The belt also tends to wedge into the groove as the load increases—the greater the load, the greater the wedging action—improving transmission and making the V-belt an effective solution, needing less width and tension than flat belts. V-belts trump flat belts with their small center distances and high reduction ratios. The preferred center distance is larger than the largest pulley diameter, but less than three times the sum of both pulleys. Optimal speed range is 1,000–7,000 ft/min (300–2,130 m/min). V-belts need larger pulleys for their thicker cross-section than flat belts.For high-power requirements, two or more V-belts can be joined side-by-side in an arrangement called a multi-V, running on matching multi-groove sheaves. This is known as a multiple-V-belt drive (or sometimes a 'classical V-belt drive').V-belts may be homogeneously rubber or polymer throughout, or there may be fibers embedded in the rubber or polymer for strength and reinforcement. The fibers may be of textile materials such as cotton, (such as ) or polyester or, for greatest strength, of steel or (such as, or ).When an endless belt does not fit the need, jointed and link V-belts may be employed.
Most models offer the same power and speed ratings as equivalently-sized endless belts and do not require special pulleys to operate. A link v-belt is a number of polyurethane/polyester composite links held together, either by themselves, such as Fenner Drives' PowerTwist, or Nu-T-Link (with metal studs).
These provide easy installation and superior environmental resistance compared to rubber belts and are length-adjustable by disassembling and removing links when needed.V-belt history Trade journal coverage of V-belts in automobiles from 1916 mentioned leather as the belt material, and mentioned that the V angle was not yet well standardized. The endless rubber V-belt was developed in 1917 by John Gates of the. Multiple-V-belt drive was first arranged a few years later by Walter Geist of the corporation, who was inspired to replace the single rope of multi-groove-sheave with multiple V-belts running parallel. Geist filed for a patent in 1925, and Allis-Chalmers began marketing the drive under the 'Texrope' brand; the patent was granted in 1928 ( ). The 'Texrope' brand still exists, although it has changed ownership and no longer refers to multiple-V-belt drive alone.Multi-groove belts A multi-groove, V-Ribbed, or polygroove belt is made up of usually between 3 and 24 'V' shaped sections alongside each other. This gives a thinner belt for the same drive surface, thus it is more flexible, although often wider. The added flexibility offers an improved efficiency, as less energy is wasted in the internal friction of continually bending the belt.
In practice this gain of efficiency causes a reduced heating effect on the belt, and a cooler-running belt lasts longer in service. Belts are commercially available in several sizes, with usually a 'P' (sometimes omitted) and a single letter identifying the pitch between grooves. The 'PK' section with a pitch of 3.56 mm is commonly used for automotive applications.A further advantage of the polygroove belt that makes them popular is that they can run over pulleys on the ungrooved back of the belt.
Though this is sometimes done with V-belts with a single idler pulley for tensioning, a polygroove belt may be wrapped around a pulley on its back tightly enough to change its direction, or even to provide a light driving force.Any V-belt's ability to drive pulleys depends on wrapping the belt around a sufficient angle of the pulley to provide grip. Where a single-V-belt is limited to a simple convex shape, it can adequately wrap at most three or possibly four pulleys, so can drive at most three accessories. Where more must be driven, such as for modern cars with power steering and air conditioning, multiple belts are required. As the polygroove belt can be bent into concave paths by external idlers, it can wrap any number of driven pulleys, limited only by the power capacity of the belt.This ability to bend the belt at the designer's whim allows it to take a complex or ' path. This can assist the design of a compact engine layout, where the accessories are mounted more closely to the engine block and without the need to provide movable tensioning adjustments. The entire belt may be tensioned by a single idler pulley.Ribbed belt A ribbed belt is a power transmission belt featuring lengthwise grooves. It operates from contact between the ribs of the belt and the grooves in the pulley.
Its single-piece structure is reported to offer an even distribution of tension across the width of the pulley where the belt is in contact, a power range up to 600 kW, a high speed ratio, serpentine drives (possibility to drive off the back of the belt), long life, stability and homogeneity of the drive tension, and reduced vibration. The ribbed belt may be fitted on various applications: compressors, fitness bikes, agricultural machinery, food mixers, washing machines, lawn mowers, etc.Film belts Though often grouped with flat belts, they are actually a different kind. They consist of a very thin belt (0.5–15 millimeters or 100–4000 micrometres) strip of plastic and occasionally rubber. They are generally intended for low-power (less than 10 watts), high-speed uses, allowing high efficiency (up to 98%) and long life. These are seen in business machines, printers, tape recorders, and other light-duty operations.Timing belts. Belt-drive cog on a(also known as toothed, notch, cog, or synchronous belts) are a positive transfer belt and can track relative movement.
These belts have teeth that fit into a matching toothed pulley. When correctly tensioned, they have no slippage, run at constant speed, and are often used to transfer direct motion for indexing or timing purposes (hence their name). They are often used instead of chains or gears, so there is less noise and a lubrication bath is not necessary. Of automobiles, miniature timing systems, and often utilize these belts.
Timing belts need the least tension of all belts and are among the most efficient. They can bear up to 200 hp (150 kW) at speeds of 16,000 ft/min (4,900 m/min).Timing belts with a helical offset tooth design are available. The helical offset tooth design forms a chevron pattern and causes the teeth to engage progressively. Main article:Belt drives depend on to operate, but excessive friction wastes energy and rapidly wears the belt.
Factors that affect belt friction include belt tension, contact angle, and the materials used to make the belt and pulleys.Belt tension Power transmission is a function of belt tension. However, also increasing with tension is stress (load) on the belt and bearings. The ideal belt is that of the lowest tension that does not slip in high loads.
Belt tensions should also be adjusted to belt type, size, speed, and pulley diameters. Belt tension is determined by measuring the force to deflect the belt a given distance per inch of pulley. Timing belts need only adequate tension to keep the belt in contact with the pulley.Belt wear Fatigue, more so than abrasion, is the culprit for most belt problems. This wear is caused by stress from rolling around the pulleys. High belt tension; excessive slippage; adverse environmental conditions; and belt overloads caused by shock, vibration, or belt slapping all contribute to belt fatigue.Belt vibration signatures are widely used for studying belt drive malfunctions.
Some of the common malfunctions or faults include the effects of belt, speed, and misalignment conditions. The effect of sheave Eccentricity on vibration signatures of the belt drive is quite significant. Although, vibration magnitude is not necessarily increased by this it will create strong amplitude modulation.
When the top section of a belt is in, the vibrations of the machine is increased. However, an increase in the machine vibration is not significant when only the bottom section of the belt is in resonance.
Mechanical Conveyors Selection And Operation Pdf To Jpg Document
The vibration spectrum has the tendency to move to higher frequencies as the tension force of the belt is increased.Belt dressing Belt slippage can be addressed in several ways. Belt replacement is an obvious solution, and eventually the mandatory one (because no belt lasts forever).
Often, though, before the replacement option is executed, retensioning (via pulley centerline adjustment) or dressing (with any of various coatings) may be successful to extend the belt's lifespan and postpone replacement. Belt dressings are typically liquids that are poured, brushed, dripped, or sprayed onto the belt surface and allowed to spread around; they are meant to recondition the belt's driving surfaces and increase friction between the belt and the pulleys. Some belt dressings are dark and sticky, resembling or; some are thin and clear, resembling. Some are sold to the public in at auto parts stores; others are sold in drums only to industrial users.Specifications To fully specify a belt, the material, length, and cross-section size and shape are required. Timing belts, in addition, require that the size of the teeth be given.The length of the belt is the sum of the central length of the system on both sides, half the circumference of both pulleys, and the square of the sum (if crossed) or the difference (if open) of the radii.
Thus, when dividing by the central distance, it can be visualized as the central distance times the height that gives the same squared value of the radius difference on, of course, both sides. When adding to the length of either side, the length of the belt increases, in a similar manner to the Pythagorean theorem. One important concept to remember is that as D 1 gets closer to D 2 there is less of a distance (and therefore less addition of length) until its approaches zero.On the other hand, in a crossed belt drive the sum rather than the difference of radii is the basis for computation for length. So the wider the small drive increases, the belt length is higher.V-belt profiles.
Belt Conveyor Pdf
Needham (1988), Volume 5, Part 9, 207–208. ^ Needham (1986), Volume 4, Part 2, 108. Needham (1988), Volume 5, Part 9, 160–163.
By Rhys Jenkins, Newcomen Society, (1971). Links in the History of Engineering and Technology from Tudor Times, Ayer Publishing. Page 34,. James N. Farm Collector.
Retrieved 2010-04-04. (PDF). North Dakota Statue Univ. Archived from (PDF) on 2009-06-12. Retrieved 2008-11-19. Hit N Miss Enterprises.
From the original on 17 March 2010. Retrieved 2010-04-04. Robert Grimshaw, Vol. 9 (July 1892); pages 219–224. John J. Flather, Wiley, New York, 1895. A Modern Cement Plant Installation,.
1902); pages 17–19 and 29. Note: This journal is the house organ of the Dodge Manufacturing Company and is mostly devoted rope-power systems.
Editorial staff (1916-04-15), Horseless Age, 37 (8): 324. Editorial staff (1916-04-15), Horseless Age, 37 (8): 322. DIN 7867. (PDF). ^ Automotive Handbook (3rd ed.). Retrieved 2009-10-24.