Neal consulting Engineers operate over a wide range of industry sectors. Examples of our work can be found on this page – use the image links to take you to the sector of interest:
Wind turbine gearbox failures: NCEL has investigated reliability issues with various models of wind turbine gearboxes. Root causes have included assembly errors, lubrication deficiencies, thermal expansion issues, manufacturing defects.
Wind turbine main shaft bearings: Premature failures of main shaft bearings were studied, root causes were a combination of manufacturing defects and lubrication issues.
Premature failures of aerator drives: A major sewage works in a capital city experienced short lives on several hundred new aerator geared motor drives. Investigation revealed inadequate sealing permitting water ingress, combined with inadequate design safety margins. A detailed specification for improved life units was drawn up, and replacement drive units were procured.
Archimedes screw pump drive failures: Gear tooth pitting and spalling failures were occurring. Investigation showed that the gears were adequately designed, but that overheating had occurred in early service due to a lack of oil coolers, which had resulted in surface wear on the teeth, which subsequently triggered tooth spalling failures.
RBC (rotating biological contactor) bearing failures: The entire bearing units were failing prematurely, and also overloading and damaging their attachment bolts. Studies revealed that the design had failed to take into account some components of the forces applied to the bearings.
Rolling stock axle-box bearing failures: Various studies have been conducted for various train users. Even a small failure rate is unacceptable because the failure or seizure of an axle-box bearing risks derailment. Root causes have included electrical current damage, thermal expansion issues, and contaminants such as water or dust entering the bearing.
Escalator step chain reliability and development: Studies for a major city metro system showed that premature wear of escalator step chains was a major cause of unreliability and maintenance cost. Lost lubricant (oil or grease) was a fire risk that required eliminating or controlling. We devised, rig tested and piloted a new design of step chain that required minimal lubrication and was more reliable than existing standard chain. This innovation has since been adopted in various metro systems.
Passenger lift rope failures: A major city metro was experiencing unacceptable short rope lives on some passenger lifts. Investigations showed that the lift mechanism design, although meeting all mandatory standards, was inherently sub-optimal for the operating duty. Improvements were made to the operating regime, and enhanced rope lubrication was introduced. An improved specification was suggested for future lift mechanism procurement.
Points failures: Study of failures in service of rail “switches” (also called “points” or “turnouts”), and assessment of design improvements for the actuator and sensing mechanisms to enhance reliability.
Internal Combustion Engine Failures: Diesel, gasoline and gas IC engines rely on various highly stressed tribological components, which can fail for various reasons. Numerous studies have been conducted for engine manufacturers, and also for users. Topics have included piston ring and cylinder liner wear, bearing failures, crankshaft failures, camshaft wear, and other issues.
Engines studied have ranged from small motorcycle engines, through truck and locomotive engines, generator engines, up to large slow speed marine 2-stroke Diesel engines. The same tribological principles apply to all sizes, though the design details, and the optimal solutions to problems, vary considerably.
Steam turbine and gas turbine bearing failure investigations: Several such investigations have been conducted. Root causes discovered have included assembly and commissioning defects, poor oil filtration, electrical grounding brushes malfunctioning, electrical current damage, inadequate oil film generation during rundown, incorrect settings on jacking oil systems.
Cooling tower fan gearbox studies: A common cause of failure discovered has been water ingress into the gearbox oil, other failure modes seen include system vibration frequencies resonating with blade passing frequency, gearbox manufacturing defects, incorrect oil levels in gearboxes, inadequate cooling of gearboxes.
Hydropower turbines thrust bearing failures: Large hydropower turbines can suffer thrust bearing problems and wipes during start-up and warm-up, due to thermally induced distortion of the bearing pads.
Flywheel energy storage bearing system design: A study of bearing systems for ultra high speed flywheels in a vacuum environment, including some novel options.
Emergency generator engine failures on startup: Generators used as part of uninterruptible power supplies suffered sporadic crankshaft bearing failures a few minutes after startup. The damage was severe and obscured the initiating causes, but after inspections of several engines it was found that vibration damage occurring when the engine was stationary was the initiating cause of failure. Changes were introduced including frequent pre-lubrication, and recommended changes to the bearing material.
Drift mine main conveyor failure: The failure, which interrupted all production at a major coal mine, was found to be caused by manufacturing defects and non-optimum design of the main head shaft support bearings, which had been specially designed and made for this application.
Stacker-reclaimer slewing bearing failures: Premature failures were found to be caused by non-uniform stiffness of the structure supporting the bearing, which resulted in “hard spots” that increased the rolling contact stresses locally in parts of the bearing circumference.
Conveyor belt failure: Long belt conveyors handling coal at a power station suffered excessive vibration and premature failure of the drive system. The cause was found to be a design defect that induced a critical speed whirling vibration of the high speed input shaft.
Skip winch drive gears premature pitting: The winch gears, approximately 4 meters diameter, were found to suffer misalignment due to a combination of setting-up at installation, and elastic deflections of the drum shaft under load. Fitting crowned pinions and improving the alignment solved the problem.
Marine engine failures: These have included bearing failures, camshaft wear, piston ring sticking, and general wear caused by lubrication and filtration deficiencies. On some occasions design deficiencies have been found, and advice given on design improvements.
Deck crane failures: Slewing bearing and jib heel bearings failures have been investigated by Neale Consulting Engineers. These failures, if not caught in time, can result in catastrophic toppling of the whole crane, or collapse of the jib, with risks of injury and fatality.
Propeller shaft stern tube bearing failures: Various failures have been investigated, causes include seal leakage permitting water entry, and excess misalignment caused by dynamic forces during maneuvering.
FPSO turret system failure: The main turret of a large FPSO, supported on a multiple wheel and rail turntable, malfunctioned. Investigations showed that due to poor or absent lubrication, frictional forces became magnified and caused the rollers to mis-track, damaging the rails and risking jamming of the turntable.
Design assessment and advice on a controllable pitch propeller mechanism using unlubricated components: Legislation on oil leaks into the marine environment led to the development of a system that could operate unlubricated in a seawater environment.
Thruster gearbox failures: A detailed study of the design revealed deficiencies in strength and flexibility of various components, which in turn adversely affected the lives of the bearings and gears.
Development assistance to a textile machine manufacturer: Key reciprocating components were operating at close to their fundamental limits, and redesign was carried out to reduce reciprocating forces and increase load capacity, thereby increasing the machine’s speed capability.
Investigation of repeated clutch/brake failures in a 1300 tonne forging press: Multiple causes were found, the principal one being material defects in the clutch friction plates.
Cement mill main drive gearbox failure: Replacement gears for an existing machine failed from scuffing during early running. Various measures, including supplementary oil cooling and extra fine oil filtration were applied in order to assist running-in.
Iron ore processing plant polishing plant gearbox failure investigations: Multiple causes were found, including the gearboxes being undersized for the duty, due to limited physical space being available in the machine configuration. Improvements to lubrication, and to internal gear alignment procedures were suggested, to avoid major redesign of the machine.
Disintegrator fatigue failure: Mechanical “disintegrators” used in the production of wheat gluten and related products suffered fatigue failure of the rotating beaters. Investigation showed resonant vibrations were occurring, and also the mechanical clamping of the beaters assembly was inadequate leading to fretting damage and consequent fatigue crack initiation. The problems were addressed by minor redesign.
Investigation of vibration problems in a flour mill: The problem was so severe that the floor in the area around a machine could not be walked on. Resonant vibration of the floor structure was found to coincide with an excitation frequency generated by the machine. Changes to the floor structure were required to solve the problem.
Limited Slip Differential: Design assessment of a novel design of limited slip differential that avoided use of gears. The study identified the tribological and dynamic force limitations of the design.
Design review of a motorcycle gearbox: Study of the design at the drawing board stage enabled a number of improvements to be incorporated that greatly enhanced the lives of bearings and the safety factors in the gears.
Cylinder bore coatings: Study of surface coatings and surface treatments for Aluminum cylinder bores in small car and motorcycle engines.
Crash investigation support: Neale Consulting Engineers has participated in several investigations of crashes of helicopters and fixed wing aircraft, providing advice and analysis of tribological components such as bearings, gears, clutches, screw jacks, and also lubrication and maintenance regimes.
Design of a wind pump for manufacture and use in developing countries: This design was successfully implemented in several countries, and also won a design award from the Worshipful Company of Turners. A later development, the “Poldaw” wind pump, was also highly successful, with approximately 2000 machines supplied to date from factories in Africa and Asia.
Water turbines: Redesign of water turbines for manufacture and use in small scale hydro power schemes in developing countries.
Handpumps: Design and development of a handpump for use on boreholes at depths of up to 90 metres, deeper than the limits of most existing public domain handpumps. A four year test programme, with some modifications along the way, established the viability of the design.
Riser pipe design: Development and testing of a low cost corrosion-proof riser pipe system for the India Mk2 handpump, which is the most popular rural village handpump in the world, but suffers corrosion problems in aggressive water conditions prevalent in many regions.
Expert witness & legal support: Many of the machine investigations described have been commissioned due to a legal dispute. In addition, Neale Consulting Engineers has given evidence in Patent disputes involving machinery and devices, and also personal injury cases involving machinery.