Leaking seals

Potential problems associated with centrifuges include mechanical friction from bearings vibration leaking seals static electricity and overspeed. 

Often, centrifugal pumps develop seal leaks. If the suction of a centrifugal pump is under a vacuum, air will be drawn into the pump through the leaking seal. The pump s capacity will be severely reduced. To stop the suspected air leak, I sprayed water from a hose over the pump s seal. Now, instead of sucking air, the leaking seal drew in cold water. As a result... 

Condensate, however, may not always be usable as boiler feedwater, due to the presence of certain process contaminants (see Table 1). When steam is used for heating, to power equipment, and for varied process applications, condensate comes into contact with oil and other impurities. Contamination from fuel-oil heaters or leaking seals in steam-driven equipment, such as pumps, turbines or compressors, is common. Also, the raw water used as plant makeup, may contain significant levels of solvents, uel oils, gasolines and greases. In addition to these general contamination sources, each industry has its unique one. (Table II). If any of these contaminants become entrained in the returned condensate stream, numerous and sometimes unpredictable problems in the boiler and related systems cs.n occur. 

Edwards, S.C. (1993a) Leak sealing, in The Repair of Concrete Structures (eds R.T.L. Allen, S.C. Edwards and J.D.N. Shaw), Blackie Academic Professional, Glasgow, pp. 117-19. 

Edwards, S.C. (1993a) Leak sealing, in The Repair of Concrete Structures (eds R.T.L. Allen, S.C. Edwards and J.D.N. Shaw), Blackie Academic Professional, Glasgow, pp. 117-19. Edwards, S.C. (1993b) Surface coatings, in The Repair of Concrete Structures (eds R.T.L. Allen, S.C. Edwards and J.D.N. Shaw), Blackie Academic Professional, Glasgow, pp. 122-39. 

Leaks. —> Check for loose fittings, pump leaks, seals. 

Pump condition - Check for worn and/or leaking seals and packing. 

Check the product conductivity at each housing to isolate the leaking seals... 

Seals which leak more than 0.5 cc per hour are still useful for many applications and might be specified as zero leak seals in many testing programs, but in the present study, any seals which leaked more than 0.5 cc per hour were rejected as unsatisfactory. 

Before beginning work within the enclosure and at the beginning of each shift, the NPE shall be inspected for breaches and smoke-tested for leaks, and any leaks sealed. 

Glovebags shall be smoke-tested for leaks and any leaks sealed prior to use. 

Leaking seal (liquid squirting out around the shaft)... 

Destructive afterburn can then result in the preheater. The leaking seal... 

FIGURE 15-8 Air preheater with leaking seal (courtesy Oil Gas Journal)... 

Air can also be drawn into the suction of the pump through a bad seal. Try increasing the seal oil pressure to see if this suppresses cavitation. It is also possible to pour seal oil from a can over the seal to test for a leaking seal. However, take precautions because this could cause a seal oil fire. 

Insufficient quench Overflow of TGO pan Too much gland oil pressure Leaking seal Suction screen plugged Air leak in suction piping... 

The NRC issued an information notice to alert licensees to an application of an on-line leak sealing process which substantially degraded the integrity of the reactor coolant pressure boundary and has worked with the industry on the proper application of on-line leak sealants. 

USNRC Inspection Manual Part 9900, Assessing on-line leak sealing of ASME Code class 1 2, October 19, 1994. 

On-Line leak sealing A guide for nuclear power plant maintenance personnel, July 1989, Electric Power Research Institute... 

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