• 书名:机械故障分析和故障排除
  • 价格:¥864 (不含邮费)
  • 作者:Butterworth-Heinemann
  • 购买咨询电话:0756-3360980-8013
  • 咨询邮箱:fengren@lclube.com.cn

Description

Solve the machinery failure problems costing you time and money with this classic, comprehensive guide to analysis and troubleshooting

  • Provides detailed, complete and accurate information on anticipating risk of component failure and avoiding equipment downtime
  • Includes numerous photographs of failed parts to ensure you are familiar with the visual evidence you need to recognize
  • Covers proven approaches to failure definition and offers failure identification and analysis methods that can be applied to virtually all problem situations
  • Demonstrates with examples how the progress and results of failure analysis and troubleshooting efforts can be documented and monitored

Failures of machinery in a plant setting can have wide-ranging consequences and in order to stay competitive, corporations across all industries must optimize the efficiency and reliability of their machinery.

Machinery Failure Analysis and Troubleshooting is a trusted, established reference in the field, authored by two well-known authorities on failure and reliability. Structured to teach failure identification and analysis methods that can be applied to almost all problem situations, this eagerly awaited update takes in the wealth of technological advances and changes in approach seen since the last edition published more than a decade ago.

Covering both the engineering detail and management theory, Machinery Failure Analysis and Troubleshooting provides a robust go-to reference and training resource for all engineers and managers working in manufacturing and process plants.

Author:

 Heinz P. Bloch and Fred K. Geitner

Published:

 2012

Format:

 Hardback

Pages:

 760

Excerpt:

"A rather large number of factors influences lubricating oil degradation and, consequently, pump bearing life. If your centrifugal pumps are equipped with rolling element bearings, there is little doubt that medium viscosity turbine oils (ISO Grade 68) will perform better than the lighter oils originally specified by many pump manufacturers. But, by far, the most frequent cause of lube-oil-related failure incidents is water and dirt contamination. With only 20 ppm water in pure mineral oil, bearing surface and rolling element fatigue life is reduced by an incredible 48 percent. Although the fatigue life reduction is less pronounced with inhibited lubricants, there are always compelling reasons to exclude dirt and water from pump bearing housings. Lip seals are a poor choice for centrifugal pump installations demanding high reliability. Face seals represent superior, "hermetic" sealing and should be given serious consideration.

"On a related subject, have you explained to your operators and maintenance personnel that a full-bottle oiler is no guarantee of adequate lubrication? The height of the beveled tube determines the level of oil in the bearing housing, and all too often there will be costly misunderstandings. However, there are at least two considerably more elusive problems involving bottle oilers.

"The first of these is that bottle oilers may malfunction unless suitably large bearing housing vents are provided. With a relatively viscous oil and close clearance at the bearing housing seal, an oil film may exist between seal bore and shaft surface. Good lube oils have a certain film strength and under certain operating conditions, this sealing film near the bearing end cap may break only if the pressure difference bearing housing interior-to-surrounding atmosphere exceeds 3/8 inch of water column.

"If now, the bearing housing is exposed to a temperature increase of a few degrees, the trapped vapors - usually an air-oil mix - floating above the liquid oil level will expand and the pressure may rise 1/4 inch of water column. While this would not be sufficient to rupture the oil film so as to establish equilibrium between atmosphere and bearing housing interior, the pressure buildup is nevertheless sufficient to depress the oil level from its former location near the center of a bearing ball at the 6 o'clock position to a new level now barely touching the extreme bottom of the lowermost bearing rolling element. At that time, the bearing will overheat and the lube oil in contact with it will carbonize. An oil analysis will usually determine that the resulting blackening of the oil is due to this high temperature degradation.

"The second of the elusive oil-related problems often causes the contents of bottle oilers to turn grayish color. This one is primarily observed on ring-oil lubricated rolling element bearings.

"Suppose you have very precisely aligned the shafts of pump and driver; nevertheless, shims placed under the equipment feet in order to achieve this precise alignment caused the shaft system to slant 0.005" or 0.010" per foot of shaft length. As a consequence, the brass or bronze oil slinger ring will now exhibit a strong tendency to run "downhill." Thus bumping into other pump components thousands of times per day, the slinger ring gradually degrades and sheds numerous tiny specks of the alloy material. The specks of metal cause progressive oil deterioration and, ultimately, bearing distress.

"Pump users may wish to pursue one of two time-tested preventive measures. First, use properly vented bearing housings or, better yet, hermetically sealed bearing housings without oiler bottles. The latter are offered by some pump manufacturers and incorporate bull's-eye-type sight glasses to ascertain proper oil levels.

"The second preventive measure would take into account the need for radically improved pump and driver leveling during shaft alignment or, even more desirable, apply flinger spools. Of course, oil mist lubrication or direct oil injection into the bearings would represent an altogether more dependable, long- term satisfactory lube application method for centrifugal pumps."


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