Submersible pump

Claim 2

A submersible pump for the transfer of liquids comprising a drive mechanism, a substantially vertically depending cylindrical shaft extending from and rotable around its axis by said drive mechanism, said shaft having a length which is greater than eighty times the means radius of its outer surface and having a free end remote from said drive mechanism and said shaft being free of support bearings between said drive mechanism and said free end, a stationary impeller housing at said free end of said shaft-and extending around the axis of said shaft, said housing having fluid inlet and outlet openings, an impeller in only said housing and mounted on said shaft at the free end thereof for rotation therewith and a stationary guide tube intermediate said housing and said drive mechanism and depending from the drive mechanism housing, said guide tube being co-axial with and surrounding said shaft and having an inner surface mean radius which is greater than said mean radius of said outer surface of said shaft, the ratio of said latter outer surface radius to said inner surface radius being in the critical range of 1:1.15 to 1: 2.0 and said shaft otherwise being free of contact with stationary bearings and glands from said free end thereof to said drive mechanism.

Claim 3

A submersible pump as set forth in claim 1, said ratio of said outer surface radius to said inner surface radius is in the range from 1:1.15 to 1:1.5.

Claim 4

A submersible pump as set forth in claim 1, wherein the length of said guide tube which surrounds said shaft is at least 10 times said means radius of the outer surface of said shaft.

Claim 5

A submersible pump as set forth in claim 1, wherein the length of said guide tube which surrounds said shaft is at least 20 times said mean radius of the outer surface of said shaft.

Claim 6

A submersible pump as set forth in claim 1, wherein the drive mechanism is an electric motor.

Claim 7

A submersible pump for the transfer of liquids comprising a drive mechanism, a substantially vertically depending cylindrical shaft extending from and rotatable around its axis by said drive mechanism, said shaft having a length which is greater than eighty times the mean radius of its outer surface and having a free end remote from said drive mechanism, a stationary impeller housing at said free end of said shaft and extending around the axis of said shaft, said housing having a wall extending transversely to said axis and an opening therethrough larger than the diameter of said shaft so as to provide space around said shaft intermediate it and said wall and said housing having an outlet opening, an impeller in said housing on the side of said wall opposite from said drive mechanism and mounted on said sjaft at the free end thereof for rotation therewith and a stationary guide tube intermediate said wall and said drive mechanism and depending from the drive mechanism housing, said guide tube being co-axial with and surrounding said shaft and having its end nearer said wall spaced from said wall in the direction of said drive mechanism, said guide tube also having an inner surface mean radius which is greater than said mean radius of said outer surface of said shaft, the ratio of said latter outer surface radius to said inner surface radius being in the critical raNge of 1:1.15 to 1:2.0 and said shaft otherwise being free of contact with stationary bearings and glands from said free end thereof to said drive mechanism.

Claim 8

A submersible pump for the transfer of liquids comprising a drive mechanism, a substantially vertically depending cylindrical shaft extending from and rotatable around its axis by said drive mechanism, said shaft having a length which is greater than eighty times the mean radius of its outer surface and having a free end remote from said drive mechanism, a stationary impeller housing at said free end of said shaft and extending around the axis of said shaft, said housing having a wall extending transversely to said axis and an opening therethrough larger than the diameter of said shaft so as to provide space around said shaft intermediate it and said wall and said housing having an outlet opening, an impeller in said housing on the side of said wall opposite from said drive mechanism and mounted on said sjaft at the free end thereof for rotation therewith and a stationary guide tube intermediate said wall and said drive mechanism and depending from the drive mechanism housing, said guide tube being co-axial with and surrounding said shaft and having its end nearer said wall spaced from said wall in the direction of said drive mechanism, said guide tube also having an inner surface mean radius which is greater than said mean radius of said outer surface of said shaft, the ratio of said latter outer surface radius to said inner surface radius being in the critical raNge of 1:1.15 to 1:2.0 and said shaft otherwise being free of contact with stationary bearings and glands from said free end thereof to said drive mechanism.