Test Results for PTFE-Faced Thrust Pads, With Direct Comparison Against Babbitt-Faced Pads and Correlation With Analysis

Ettles, C. M. McC.; Knox, R T; Ferguson, J. H.; Hörner, Dietrich

doi:10.1115/1.1576427

Cited by 37 publications

(23 citation statements)

References 12 publications

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“…Thus, the tested PEEK lined pads and babbitt lined pads have similar power losses under the same speed and load conditions. This observation for PEEK and babbitt pads is in agreement with the direct comparison between PTFE lined pads and babbitt lined pads of two thrust bearings that were tested [9]. Figure 10 shows that the PEEK lined pads had a lower maximum 50/60 temperature over the tested range for the embedded instruments than the babbitt lined pads.…”

Section: Load Capacitysupporting

confidence: 78%

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Experimental Performance Study of a High Speed Oil Lubricated Polymer Thrust Bearing

et al. 2015

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Abstract:With the demand for turbomachinery to operate at higher speeds, loads, and power, fluid film bearings that support turbomachinery must be capable of operating in these more demanding applications. Thrust bearings operating at high speeds and loads can experience high surface temperatures and thin fluid film thickness. Typically, babbitt (white metal) is the bearing lining material for most turbomachinery bearings but is limited in operating temperature and allowable film thickness. Polymer based materials are alternative materials that can operate at high temperatures and with thin films and have been in use for many decades in high load applications, such as electric submersible pumps (ESP). Test results of polymer lined thrust bearings subjected to modern turbomachinery speeds and loads are presented and compared to babbitt lined bearings of the same design and under similar conditions. The test results show polymer lined thrust bearings can operate at higher bearing unit loads than babbitt.

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Section: Load Capacitysupporting

confidence: 78%

“…PTFE and babbitt comparisons have been published by Ettles, et al [9]. A comparison of PEEK and babbitt has not been published for high speeds and loads.…”

Section: Introductionmentioning

confidence: 99%

Experimental Performance Study of a High Speed Oil Lubricated Polymer Thrust Bearing

et al. 2015

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“…The coupling of the oil film pressure to elastic deformation of the surface has shown interesting phenomena [2]; at higher specific pressures the film becomes almost parallel with a constriction at the outlet similar to that found in conventional elastohydrodynamic lubrication. The minimum film is therefore at this constriction around the pad sides and trailing edge.…”

Section: Introductionmentioning

confidence: 97%

“…The use of PTFE faced thrust pads has a number of advantages. Testing has shown [2] that the pads can withstand a specific pressure (load divided by the surface area of the pads) up to 10 MPa, significantly higher than that which can be achieved with babbit. The PTFE thermally insulates the pad from the oil film so that there is less thermal crowing of the pad.…”

Section: Introductionmentioning

confidence: 99%

Oil film measurment in polytetrafluoroethylene-faced thurst pad bearings for hydrogenerator applications

Dwyer-Joyce

Harper

Pritchard

et al. 2006

Proceedings of the Institution of Mechanical Engineers, Part A:

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There is a growing trend in the replacement of the babbit facing in thrust pad bearings with a composite PTFE surface layer. The PTFE faced bearings have been shown to allow a greater specific pressure, reduce thermal crowning, and in some cases negate the need for an oil-lift (jacking) system. These designs of bearing require new methods for the measurement of oil film thickness both to assist in their development and for plant condition monitoring. In this work, an ultrasonic method of oil film measurement is evaluated for this purpose. An ultrasonic transducer is mounted on the back face of the thrust pad. Pulses are generated and transmitted through the pad material, bonding interlayer, and PTFE surface layer. The proportion of the wave that reflects back from the oil film layer is determined. This is then related to the oil film thickness using a series of calibration experiments and a spring stiffness model. In practice the reflected signal is difficult to distinguish, in the time domain, from other internal reflections from the pad. Signals are compared with reflections when no oil film is present and processing is carried out in the frequency domain.Experiments have been performed on a full size PTFE-faced thrust pad destined for a hydroelectric power station turbine. The instrumented pad was installed in a test facility and subjected to a range of loading conditions both with and without oil lift. Whilst there were some problems with the robustness of the experimental procedure, oil films were successfully measured and used to study the effect of the oil lift system on film formation.

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“…The codes used for bearing calculations are quite sophisticated, seeming to take into account all effects significant for bearing performance, such as deformations, lubricant properties as a function of temperature and pressure, oil mixing between the pads, heat exchange, etc. [8][9][10]. However, the accuracy of these codes is not clear, as there are few papers comparing theoretical and experimental results for large bearings.…”

Section: Introductionmentioning

confidence: 99%

Field Tests on Hydrodynamic and Hybrid Operation of a Bidirectional Thrust Bearing of a Pump-Turbine

2017

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Abstract:In vertical shaft pump turbines operating in pumped storage power plants an important role is played by a thrust bearing. Due to the bidirectional character of operation, thrust bearing tilting pads have to be supported symmetrically, which is known to be unfavourable from the point of view of their performance. Large thrust bearings have to be carefully designed so as to minimise excessive thermo-elastic pad deformations. The research into fluid film thrust bearings has been quite extensive over the years, comprising theoretical studies of bearing properties with the use of more and more sophisticated calculation codes. On the other hand, the availability of experimental field data on bearing operation is limited, for obvious reasons. In this paper the authors present part of the results of extensive field tests of a large bearing of a pump-turbine they have conducted in a pumped storage power plant. Hopefully this data will be of interest to other researchers to compare theoretical predictions to measurement data.

show abstract

Test Results for PTFE-Faced Thrust Pads, With Direct Comparison Against Babbitt-Faced Pads and Correlation With Analysis

Cited by 37 publications

References 12 publications

Experimental Performance Study of a High Speed Oil Lubricated Polymer Thrust Bearing

Experimental Performance Study of a High Speed Oil Lubricated Polymer Thrust Bearing

Oil film measurment in polytetrafluoroethylene-faced thurst pad bearings for hydrogenerator applications

Field Tests on Hydrodynamic and Hybrid Operation of a Bidirectional Thrust Bearing of a Pump-Turbine

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