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Daniel Ausling delivered the presentation at 2014 Bulk Materials Handling Conference. The 11th annual Bulk Materials Handling Conference is an expert led forum focusing on the engineering behind the latest expansions and upgrades of bulk materials facilities. This conference will evaluate the latest engineering feats that are creating record levels of throughput whilst minimising downtime. For more information about the event, please visit: http://www.informa.com.au/bulkmaterials14
Citation preview
Quality Assurance Test Methods Rela5ng to Conveyor Idler Rolls and
Prac5cal Consequences
Mr Daniel Ausling Consul'ng Engineer TUNRA Bulk Solidsin associa5on with
The Centre for Bulk Solids & Par5culate Technologies The University of Newcastle
Overview
• Standard Rolling Resistance and extensions • Dust and Moisture Ingress Tes5ng • Total Indicated Run-‐out (TIR) • Maximum Indicated Slope (MIS) • Noise Tes5ng • Dynamic Unbalance • Internal inspec5on for comparison • Underground Applica5ons (FRAS Tes5ng) • Changing Selec5on Criteria for varying applica5ons • Push for a new Australian Standard
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Idler Rota5onal Resistance
• Represents one of three sta5c mo5on resistance of conveyor systems.
• Indenta5on Rolling Resistance • Belt/Bulk Material Flexure • Idler Rota5onal Resistance
• Significance in total mo5on resistance varies from minor to significant depending on system layout/design.
• Basic measure of idler rota5on resistance is commonly known as Rim Drag tes5ng.
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Rim Drag Tes5ng
• TBS rim drag tes5ng apparatus • Other designs exist.
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Rim Drag Tes5ng
• Most common tes5ng conducted at “standard condi5ons”
• 25kg Load (equivalent to no load) • 20-‐25oC Ambient Temperature • Variable Speed – generally tailored for specific client applica5on
• Varia5on in behaviour exists as test condi5ons change
• Varia5on with temperature • Varia5on with rota5onal speed • Varia5on with load
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Rim Drag Tes5ng
• Important to consider and test for idler behaviour under all condi5ons expected to be experienced during idler life5me.
• Also consider transient behaviour.
• Ini5al behaviour – Breakaway Force • Ini5al behaviour – Maximum Start-‐Up Force
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Rim Drag Tes5ng
• Breakaway Force is force required to overcome sta5c fric5on in bearing and seal arrangements of conveyor idler rolls.
• Maximum Start-‐Up Force is the peak rota5onal resistance during the transient phase of the conveyor idler roll.
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Typical Conveyor Idler Roll Rota5onal Resistance Profile
• Force as measured at shell radius
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Idler Rota5onal Resistance – Research Data
• Example Data Set
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0
50
100
150
200
250
300
350
G1 G2 G3 G4
Force (%
)
Idler Group Number
Rim Drag
P1
Bh
Indenta5on Rolling Resistance – Idler Diameter Influence
• Generally the major mo5on resistance component in a conveyor system. • Larger diameter idler rolls leads to a lower indenta5on rolling resistance. • In appropriate applica5ons consider use of larger diameter central idler in a troughing configura5on in order to reduce indenta5on rolling resistance and load related idler component fa5gue.
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Approximate load distribution at the belt and idler roll interface
Indentation rolling resistance distribution (bottom view)
Indenta5on Rolling Resistance – Idler Diameter Influence 11
Ø125 mm Idler Roll Ø150 mm Idler Roll
Ø178 mm Idler Roll
Dust and Moisture Ingress
• Standard test exists as South African standard. • Measure of how much and how quickly fine “dust” and/or water ingresses into a seal arrangement
• Exis5ng rig provides harder test for idlers by inclining the idler face and applying a normal load.
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Dust and Moisture Ingress
• Dust Ingress rig under development to test to SANS and harsher condi5ons as required.
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Total Indicated Run-‐out (TIR) and Maximum Indicated Slope (MIS)
• TIR is a measure of the concentricity of an idler shell • TIR provides a general indica5on of the manufacturing quality of a conveyor idler roll • MIS is a measure of concentricity of an idler shell every 6 degrees. • MIS has been shown to be a reliable indicator of opera5ng noise of a conveyor idler roll. • Low noise idlers are generally required to have an average MIS of less than 0.1mm.
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TIR and MIS
• Industry specs range in recommended values. • Can depend on idler diameter, length, specifica5on document etc.
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TIR MIS
Conveyor Idler Roll Noise Tes5ng
• Two key terms: Self Noise and Opera'ng Noise • Self Noise is a measure of the noise created by the interac5on between sealing arrangement components • Opera'ng Noise is a measure of self noise and the noise created due to idler shell and conveyor belt interac5on. • Tes5ng or measures for self noise is pointless as a tool for predic5ng noise of a conveyor system.
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Conveyor Idler Roll Noise Tes5ng
• TBS Opera5ng Noise rig. As close to realis5c tes5ng as possible. • Results have greater relevance however are only directly comparable to tes5ng conducted under iden5cal condi5ons. • Self noise tes5ng can be useful as a measure of incremental improvement of successive idler designs.
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Dynamic Unbalance
• A test to determine the out-‐of-‐balance mass and loca5on for each end of the conveyor idler roll.
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Dynamic Unbalance
• Standard test speed of 650rpm however other speeds available to suit a par5cular conveyor system speed. • Another general indicator of manufacturing quality. • Lower out-‐of-‐balance mass will reduce stresses on idler componentry throughout life cycle. • Experience suggests out-‐of-‐balance masses of <10g represent very well balanced idlers. With masses of 10g-‐30g represen5ng a well balanced general purpose conveyor idler roll.
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Internal Inspec5on
• A useful tool for comparison and verifica5on of internal design specifica5ons. • Can be used as visual aid for sealing mechanism comparison for a supply tender. • Can be used as idler internal componentry verifica5on. • Can be used as inves5ga5ve means where unusual results are recorded or anomalies are found.
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Underground Systems – FRAS Tes5ng
• Fire Resistant An5-‐Sta5c test procedures are required for any non-‐steel idler components (MDG3608 – NSW Guideline). • Rag of tests to determine opera5ng performance of idlers within an underground coal mining environment.
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Underground Systems – FRAS Tes5ng
• Idler related current test range • Combus5on Propaga5on Characteris5cs (Gallery Test) • Ignitability and Maximum Surface Temperature of Idler Subject to Fric5on. • Ignitability and Flame Propaga5on Characteris5cs (Finger Burn Test) • Oxygen Index • Electrical Resis5vity • Toxicity of Products of Combus5on
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Conveyor Idler Roll Selec5on Criteria
• Purpose defines selec5on criteria. • Selec5on criteria defines scope of tes5ng.
• Consider: • Conveyor system layout • Above or below ground • Environmental extremes • Noise requirements • Life5me calcula5ons • Costs
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New Australian Standard
• Push to develop a standardised ra5ng system for conveyor idler rolls. • Example system for ranking idlers based on following characteris5cs:
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Very High High Good Standard
Shell and Bearing Fa>gue Life A B C D
Seal Effec>veness A B C D
Rim Drag A B C D
Shell Dimensional Tolerance A B C D
QUESTIONS?