Magnetic shaft seals prevent hazardous leakage from wastewater agitators
The US Department of Energy's laboratory in Miamisburg, OH, operated by Monsanto Research Corporation, processes approximately 45,000 gallons per week of low-level radioactive wastewater to meet Federal Environmental Protection Agency quality standards. Preventing the spread of radioactive contamination throughout the operating area demands effective sealing of all process piping, valves, pumps, and agitators. Rotating shafts of pumps and agitators installed a the start of operations in 1947 were sealed by stuffing glands with graphite impregnated asbestos packing. These pumps proved to be unsatisfactory. In the mid-1970's, new process pumps with mechanical seals and some with magnetic drives were installed. Later, in January 1979, new agitator shaft drives with double tandem, spring-loaded mechanical seals were installed, maintenance of these pumps was costly. The agitator drive shafts were redesigned to accommodate magnetic seals of the type successfully used in blowers and vacuum/pressure pumps in other plant locations. One inherent advantage of the magnetic seal is that it operates with a face loading as much as 50% less than a conventional spring-loaded mechanical seal. The lower loading by a predetermined uniform magnetic force contributes to long face life. Other advantages include compactness, ease of assembly with only a few parts, and insensitivity to vibration. The magnetic shaft seals installed on the agitator shafts in February 1983 are still in service without any leakage or need for maintenance. Based on current operating data and a projected five-year meantime between failures, the estimated cost benefit of the magnetic seals over spring-loaded mechanical seals over spring-loaded mechanical seals will be $640 vs $2400 respectively per seal, with 60% less downtime for maintenance.
- Research Organization:
- Monsanto Research Corp., Miamisburg, OH
- OSTI ID:
- 6757101
- Journal Information:
- Chem. Process. (Chicago); (United States), Vol. 48:14
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
LIQUID WASTES
PUMPING
LOW-LEVEL RADIOACTIVE WASTES
PUMPS
MAINTENANCE
PERFORMANCE
SEALS
SERVICE LIFE
MOUND LABORATORY
RADIOACTIVE WASTE FACILITIES
SHAFTS
MACHINE PARTS
MATERIALS
NATIONAL ORGANIZATIONS
NUCLEAR FACILITIES
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
US AEC
US DOE
US ERDA
US ORGANIZATIONS
WASTES
052001* - Nuclear Fuels- Waste Processing