Bearings with hardened rolling filements and polymeric cages for use submerged in very low temperature fluids
First Claim
1. A magnetic drive pump for use in pumping a very low temperature fluid at less than about −
- 100degrees centigrade comprising;
a back plate having a rotatable shaft journaled therein said rotatable shaft having a first end and a second end journaled in a bearing comprised of a hardened race in said back plate, a plurality of ceramic rolling filaments in said race, and a retainer comprised of a polymeric material holding said rolling filement is spaced apart position about said race;
an impeller mounted to a first end of said rotatable shaft;
a first magnet comprising a first material having coefficient of thermal expansion mounted to a second end of said rotatable shaft and contained within a casing mounted to said rotatable shaft, said casing comprising a material having a second coefficient of thermal expansion greater than the first coefficient of thermal expansion of the material comprising said magnet;
said back plate being mounted within a housing having openings formed therein for intake and exhaust of a fluid to be pumped at very low temperature; and
a second magnet positioned in close proximity to said housing for rotation therearound and adapted for mounting to the shaft of a motor for rotating said first magnet in the housing.
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Accused Products
Abstract
A selflubricating bearing for use submerged in cryogenic fluids. The self-lubricating bearing comprises hardened races, hardened rolling elements and polymeric retainers or cages. More particularly, the rolling elements maybe hardened balls, and the polymeric cages may include PEEK. In particular a bearing for self lubricated use in seal-less, magnetic drive pump for pumping fluids at very low temperaturesand cryogenic temperatures below about −100 degrees centigrade such as liquid nitrogen and temperatures below about −150 degrees centigrade such as liquefied natural gas (LNG). An environment for submerged use of such a bering may be a magnetically driven cryogentic pump with a housing having an intake and exhaust with a back plate mounted therein in which a shaft is journaled in self-lubricating bearings having hardened stainless steel or ceramic balls, stainless steel races and polymeric retainers or cages for retaining the balls for rolling contact in the races. An impeller is mounted on the first end and a first magnet is mounted on the second end of the shaft.
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Citations
20 Claims
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1. A magnetic drive pump for use in pumping a very low temperature fluid at less than about −
- 100degrees centigrade comprising;
a back plate having a rotatable shaft journaled therein said rotatable shaft having a first end and a second end journaled in a bearing comprised of a hardened race in said back plate, a plurality of ceramic rolling filaments in said race, and a retainer comprised of a polymeric material holding said rolling filement is spaced apart position about said race;
an impeller mounted to a first end of said rotatable shaft;
a first magnet comprising a first material having coefficient of thermal expansion mounted to a second end of said rotatable shaft and contained within a casing mounted to said rotatable shaft, said casing comprising a material having a second coefficient of thermal expansion greater than the first coefficient of thermal expansion of the material comprising said magnet;
said back plate being mounted within a housing having openings formed therein for intake and exhaust of a fluid to be pumped at very low temperature; and
a second magnet positioned in close proximity to said housing for rotation therearound and adapted for mounting to the shaft of a motor for rotating said first magnet in the housing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 16, 17, 18, 19)
- 100degrees centigrade comprising;
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12. A magnetic drive pump for pumping a fluid at very low temperature having an impeller mounted on a rotatable shaft journaled in a pump housing comprising said shaft being journaled in a ball bearing said ball bearing further comprising a ball race a plurality of ceramic balls and a ball retainer, wherein said ball retainer comprises a polymeric material having self-lubricating properties in fluid at said very low temperatures.
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14. A bearing for self-lubricating use submerged in a cryogenic fluid, said bearing comprising
a) an inside race comprising stainless steel, b) an outside race comprising stainless steel c) a plurality of rolling elements sized for rolling engagement between said inside race and said outside race, d) a polymeric cage holding said rolling elements spaced apart for rolling between said races.
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20. A self-lubricating bearing for use submerged in cryogenic fluid comprising:
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a) an inside race comprising stainless steel;
b) an outside race comprising stainless steel;
c) a plurality of ceramic balls sized for rolling engagement between said inside race and said outside race; and
d) a polyether ether ketone cage holding said ceramic balls spaced apart for rolling between said races.
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Specification