Centrifugal Pumps Design and Application 2nd ed - Val S. Lobanoff, Robert R. Ross (Butterworth-Heinemann, 1992)
Rolling Element Bearings and Lubrications 541 Figure 20-9. Oil mist lubrication schematic (courtesy of Alemite Division of Stewart-Warner Corporation, Chicago, Illinois). mist then passes through a reclassifier nozzle before entering the point to be lubricated. This reclassifier nozzle establishes the oil mist stream as either a mist, spray, or condensate, depending on the application of the system. Since the mid-1950s, the oil mist lubrication concept has been accepted as a proven and cost-effective means of providing lubrication for centrifugal pumps. Typical petrochemical plant pump applications are illustrated in Figures 20-10 through 20-13. Centralized oil mist systems have also been highly successful on electric motors, gears, chains, and horizontal shaft bearings such as on steam turbines and steel plant rolling mill equipment. The actual method of applying oil mist to a given piece of equipment is governed to a large extent by the type of bearing used. For sliding bearings, oil mist alone is not considered an effective means of lubrication because relatively large quantities of oil are required. In this case, oil mist is used effectively as a purge of the oil reservoir and, to a limited extent, as fresh oil make-up to the reservoir. Purge mist lubricated pumps generally use a constant level oiler with a balance line between the bearing housing and the oiler lower bowl. This type of installation, which was shown earlier in Figure 20-5, is required for bearing housings having an excessive back pressure or vacuum and is ideally suited for purge oil
542 Centrifugal Pumps: Design and Application Figure 20-10. Oil mist console suitable for lubricating 30-60 pumps in a refinery (courtesy of Lubrication Systems Company, Houston, Texas). mist applications. A constant level can be maintained in spite of pressure or vacuum in the housing as the equalizing tube provides static balance of pressure between the bearing housing and oiler bowl. Rolling element bearings, on the other hand, are ideally suited for drysump lubrication. With dry sump oil mist, the need for a lubricating oil sump is eliminated. If the equipment shaft is arranged horizontally, the lower portion of the bearing outer race serves as a mini-oil sump. The bearing is lubricated directly by a continuous supply of fresh oil condensation. Turbulence generated by bearing rotation causes oil particles suspended in the air stream to condense on the rolling elements as the mist passes through the bearings and exits to atmosphere. This technique offers four principal advantages: • Bearing wear particles are not recycled back through the bearing, but are washed off instead.
- Page 506 and 507: Vibration and Noise in Pumps 491 th
- Page 508 and 509: Vibration and Noise in Pumps 4S3 fo
- Page 510 and 511: Part 4 Extending Pump Life
- Page 512 and 513: 19 by Malcolm G. Murray, Jr. Murray
- Page 514 and 515: Alignment 499 Figure 19-2. Pump dam
- Page 516 and 517: Alignment 501 The best designs fail
- Page 518 and 519: Table 19-1 Vertical Alignment Movem
- Page 520 and 521: Table 19-2 Continued Horizontal Ali
- Page 522 and 523: Alignment 507 bearing motors becaus
- Page 524 and 525: Alignment 509 meet results. It shou
- Page 526 and 527: Alignment 511 Determination of Tole
- Page 528 and 529: Table 19-3 Continued Primary Alignm
- Page 530 and 531: Alignment 515 Figure 19-3 A & B. Tw
- Page 532 and 533: Table 19*4 Continued Methods of Cal
- Page 534 and 535: Alignment 510 parallelism/perpendic
- Page 536 and 537: Alignment 521 Table 19-5 continued
- Page 538 and 539: Alignment 523 3. Essinger, J. N., B
- Page 540 and 541: Rolling Element Bearings and Lubric
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- Page 544 and 545: Roiling Element Bearings and Lubric
- Page 546 and 547: Rolling Element Bearings and Lubric
- Page 548 and 549: Rolling Element Bearings and Lubric
- Page 550 and 551: Rolling Element Bearings and Lubric
- Page 552 and 553: Rolling Element Bearings and Lubric
- Page 554 and 555: Rolling Element Bearings and Lubric
- Page 558 and 559: Rolling Element Bearings and Lubric
- Page 560 and 561: Roiling Element Bearings and Lubric
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- Page 564 and 565: Rolling Element Bearings and Lubric
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- Page 568 and 569: Rolling Element Bearings and Lubric
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- Page 572 and 573: Failure Analysis Mechanical Seal Re
- Page 574 and 575: Table 21-2 Causes of Seal Failures
- Page 576 and 577: Mechanical Seal Reliability 561 ^mi
- Page 578 and 579: Mechanical Seal Reliability 563 Sea
- Page 580 and 581: Mechanical Seal Reliability 565 run
- Page 582 and 583: Reliability Mechanical Seal Reliabi
- Page 584 and 585: Index A thermal growth, 519-522 ver
- Page 586 and 587: Critical speed analysis. See also V
- Page 588 and 589: Index 573 inlet angle, 37 classific
- Page 590 and 591: Index 575 Shaft design, 333-343 ind
- Page 592: double, 52-54 velocity ratio, 50-51
542 <strong>Centrifugal</strong> <strong>Pumps</strong>: <strong>Design</strong> <strong>and</strong> <strong>Application</strong><br />
Figure 20-10. Oil mist console suitable for lubricating 30-60 pumps in a refinery<br />
(courtesy of Lubrication Systems Company, Houston, Texas).<br />
mist applications. A constant level can be maintain<strong>ed</strong> in spite of pressure<br />
or vacuum in the housing as the equalizing tube provides static balance of<br />
pressure between the bearing housing <strong>and</strong> oiler bowl.<br />
Rolling element bearings, on the other h<strong>and</strong>, are ideally suit<strong>ed</strong> for drysump<br />
lubrication. With dry sump oil mist, the ne<strong>ed</strong> for a lubricating oil<br />
sump is eliminat<strong>ed</strong>. If the equipment shaft is arrang<strong>ed</strong> horizontally, the<br />
lower portion of the bearing outer race serves as a mini-oil sump. The<br />
bearing is lubricat<strong>ed</strong> directly by a continuous supply of fresh oil condensation.<br />
Turbulence generat<strong>ed</strong> by bearing rotation causes oil particles suspend<strong>ed</strong><br />
in the air stream to condense on the rolling elements as the mist<br />
passes through the bearings <strong>and</strong> exits to atmosphere. This technique offers<br />
four principal advantages:<br />
• Bearing wear particles are not recycl<strong>ed</strong> back through the bearing, but<br />
are wash<strong>ed</strong> off instead.
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