HigH Tension Conveyor Pulley - ppi-global.com · ... PPI has developed a unique Finite Element Analysis ... experiences the full belt tension, every High Tension Pulley ... HigH Tension

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CORPORATE OFFICE

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800.247.1228641.628.3115fax 641.628.3658

PPI 011 11/12 Subject to change without notice PPI® is a registered trademark of Precision Inc. Copyright ©2008, Precision Pulley & Idler, All Rights Reserved

HigH Tension Conveyor Pulley

What is a High Tension Pulley?

Many think of a pulley as an assembly of parts, but to PPI it is a dynamic system. One cannot isolate the design of any one part, as any change in a part will change the loading on the rest of the pulley. These parts interact dynamically as they rotate. In order to design the assembly correctly, one must look at the complete pulley, and how the parts interact.

Typically, these pulleys are used when T1 exceeds 100,000 lbs., the shaft is 12 inches or greater in diameter, or the client desires maximum reliability for smaller shafts and lower tension.





CORPORATE OFFICE


800.247.1228641.628.3115fax 641.628.3658


PFeA

Working with state universities, PPI has developed a unique Finite Element Analysis program, PFEA. PFEA has brought new understanding to the dynamics of a conveyor pulley system Today, it is used on each and every High Tension Pulley that PPI builds. It gives our Engineers the effect of stress on life expectancy of a pulley assembly. This unique combination of PFEA and IP-Life Analysis gives our Engineers state of the art tools to design World Class High Tension Pulleys.

leT us exAmine eACH oF THe CriTiCAl ComPonenTs: end disCs

High Tension Pulleys experience very high loads transmitted from the belt through the shaft. By controlling shaft deflection, loading on the end disc and rim is minimized. While there are many different types of end discs used, they can be grouped into four main categories:

1. Welded Plate designs are the most common type of pulley construction. With appropriate engineering, they can provide good value. The disadvantage is that the stress concentration developed at the toe of the welds in the end disc can be excessive for high tension applications.

2. Integral Hub removes the welded connection between the hub and end disc. The disadvantage is higher loads on the rim weld and bushing.

3. Profile Disc improves on the Integral Hub design. Machining of the end disc reduces its stiffness and consequently the loads on the rim weld and bushing. The disadvantage is that the rim to end disc joint can still cause stress risers in this junction.

4. Turbine-T design is the ultimate in reliability. It is a smooth machined end disc from a solid piece of steel. This design moves the rim weld away from the stress concentrations in the rim-end disc connection to an area of lower stress.

rims

Because the rim experiences the full belt tension, every High Tension Pulley System rim is analyzed for stresses generated by the tension as well as the wrap of the belt, and the end couple that is caused by the bending moment being transferred to the rim by the end disc. Typically, high tension systems will be using high modulus belts, which will require the rim to be machined to insure concentricity between the rim and the shaft.

Welding

Welding is a critical part of each pulley, but its even more important in High Tension Pulley. Each weld is carefully optimized in the design phase with PFEA. However, it

does not stop there. From joint preparation, through preheat and welding, each is done to the appropriate AWS specification.






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800.247.1228641.628.3115fax 641.628.3658


AssemBly

Just as important as the construction of the parts is how they go together. Our staff is well trained, not just by Precision, but also by manufacturers of components that are to be mounted by Precision.

THermAl sTress relieve

Testing has shown a significant increase in life for pulleys that are thermally stress relieved. This cost-effective option has proven to be of such value that PPI has installed a thermal stress relief oven in our factory.

line Boring

Line boring is used for many High Tension Pulleys with locking assemblies to improve hub alignment and shaft run out. PPI line bores all pulleys with locking assemblies 240 mm or larger or as required by customer specifications.

sHAFTing

Shaft deflection and shaft bending stress are fundamental elements of High Tension Pulley System design and their limits are based on CEMA recommendations and/or customer specifications. For the High Tension Pulley, special design considerations are considered in the “land” for the locking assembly in addition to any stress concentrations in the shaft. The standard shafting used in PPI pulley assemblies is 1045. Sometimes 4140 or other materials are provided as dictated by customer specifications and/or when the design requirements exceed shafting specifications.

sHAFT Pulley ConneCTion

While the XT® hub & bushing provide reliability and a cost effective method of attaching the pulley to a shaft on conventional pulleys, keyless locking assemblies are often used on high tension pulleys. Regardless as to which is used on your conveyor, the selection of a shaft to pulley connection is extremely critical because it must transmit not only the torque, but also the bending loading between shaft and pulley. For High Tension Pulley Systems, PPI recommends keyless locking assemblies. While normally used on shafts 12 inches or greater in diameter, they are available from less than an inch (20mm) to over 23 inches (600mm) and larger upon request.






CORPORATE OFFICE


800.247.1228641.628.3115fax 641.628.3658


QuAliTy AssurAnCe

Quality begins before the steel is even purchased. To start, the design(s) must be certified before the material is ordered. Second, the material must be inspected and certified before it arrives at PPI. Then it is tracked through the system, where hold points are identified for inspection and Non-Destructive Testing, as required. Finally, when all conditions are met, it is tagged as a Precision product and is ready for shipment.

Field suPPorT

Our Field Support Engineers are stationed across the USA to help you before, during and after the manufacture of your High Tension Conveyor Pulley(s). Each member goes through an extensive and rugged 2 year training program. They have the experience and expertise to handle ANY situation.

ssP - sTATiC sHAFT Pulley

The static shaft pulley has proven itself as a cost effective alternative in Non-Drive High Tension applications. The static shaft pulley moves the spherical bearing from the pillow block to inside the hub. The advantage is that the spherical bearing acts like a hinge and does not transmit the bending of the shaft to the pulley. This allows the SSP to utilize a conventional welded product in the most demanding applications around the world.

World Wide ACCePTAnCe

Precision High Tension Pulley Systems, as well as other Precision pulley styles are in mining service throughout the world. A partial list of industries served

would include: Aggregate, Aluminum, Bauxite, Cement, Coal, Copper, Diamond, Gold, Gypsum, Iron, Lumber, Nickel, Oil Sands, Power Plants, Pulp & Paper,

Steel, Silver, Taconite, and Tunneling. A partial list of countries would include: Argentina, Aruba, Australia, Bolivia, Brazil, Canada, Chile, China, Costa

Rica, Colombia, Dominican Republic, Ecuador, Egypt, El Salvador, Germany, Guatemala, Guyana, Honduras, Hong Kong, Indonesia, Iran, Jamaica, Japan, Korea, Luxembourg, Mali, Mexico, Netherlands, New Guinea, Norway, Oman,

Peru, Philippines, Puerto Rico, Russia, Taiwan, Thailand, Trinidad, United States, Uruguay, and Venezuela.


Documents

HigH Tension Conveyor Pulley - ppi-global.com · ... PPI has developed a unique Finite Element Analysis ... experiences the full belt tension, every High Tension Pulley ... HigH Tension