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2014SumShotcreteEMag

Nozzleman Knowledge nants, or external damage can prevent a fitting from accepting grease. Try a new fitting and a more powerful greasing device in conjunction with heat and vibration to free up clogged grease channels. However, bearing assemblies which will not accept grease are often blocked with hardened residue and will require com- plete disassembly. The most common cause of major bearing failure, hardened concrete residue within bearing assembly, is completely preventable by the use of proper on-the-job lubrication practices. In closing, wet-mix pumps, properly lubri- cated, may provide many years of trouble-free service, or conversely if not maintained require frequent major repairs. Proper daily on-the-job lubrication procedures are the single largest factor determining your pump’s long-term per- Fig. 5: Properly lubricated outlet bearing assembly at 3000 hours formance and durability. displays no visible wear Wet-Mix Lubrication Checklist • Verify oil, hydraulic fluid, and water-box (a) lubricant levels before every startup. • Use the manufacturer-recommended grease or a good-quality, water-resistant grease. • Train all operators of on-the-job lubrication requirements. Be sure a functioning grease gun and a supply of grease is ALWAYS available. • Know the location of all grease fittings, even the hidden ones. • Be sure ALL grease fittings are functioning properly and readily accepting grease. If a fitting will not accept grease, immediately take necessary steps to restore greasing function. • During EVERY washout, completely flush all concrete residue from bearing assemblies before it can harden. Stroke the pump in reverse and add grease until fresh, clean grease exits all bearing surfaces. (b) ACI Certified NozzlemanOscar Duckworth is an ASA and American Concrete Institute (ACI) member with over 15,000 hours of nozzle time. He has worked as a nozzleman on over 2000 projects. Duckworth is currently an ACI Examiner for Fig. 6(a) and (b): Swing-tube shaft and outlet the wet- and dry-mix processes. He currently bearing assembly is totally destroyed at serves as ASA Executive Committee Secretary 1600 hours due to poor on-the-job lubrication and newly appointed Chair of ASA’s Education practices. Note hardened concrete residue has Committee. He continues to work as a shotcrete clogged grease grooves of outlet housing on right consultant and certified nozzleman. 36 Shotcrete • Summer 2014


2014SumShotcreteEMag
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