초록 ▼

A submersible pump system comprises a lowermost electrically driven pump unit (4,55) providing an inlet to the system for liquid to be pumped and one or more like pumps (5,55) positioned above it and connected in series. Electric power is supplied to the units by way of conductors within a central p

A submersible pump system comprises a lowermost electrically driven pump unit (4,55) providing an inlet to the system for liquid to be pumped and one or more like pumps (5,55) positioned above it and connected in series. Electric power is supplied to the units by way of conductors within a central pipe (14) concentric with an outer cofferdam pipe (12), dielectric oil being circulated through the conductor pipe and between it and the cofferdam pipe and thus through the pump unit motors which have hollow drive shafts (21) around the conductor pipe. The pump stack may be located within a well casing (52), by sealing rings (62) expanded by the dielectric oil pressure, or surrounded by an outer load-bearing pipe (10). The liquid pumped flows externally of the pump stack and the system can be constructed in separate lengths which can be readily assembled on installation.

대표청구항 ▼

1. A submersible pump system comprising a pump stack including a plurality of pump units, spaced vertically apart, each pump unit having an electric motor, impeller means driven by said electric motor, and an inlet and an outlet for liquid being pumped, the outlet of a lower pump unit communicating

1. A submersible pump system comprising a pump stack including a plurality of pump units, spaced vertically apart, each pump unit having an electric motor, impeller means driven by said electric motor, and an inlet and an outlet for liquid being pumped, the outlet of a lower pump unit communicating with the inlet of a next adjacent upper pump unit whereby said pump units operate in series, pipe means extending between said pump units, tubular electrical conductor means having an internal surface and an external surface, said tubular electrical conductor means being located within said pipe means and being connected to the electric motors of said pump units for supplying power to said motors, means including said internal surface and said external surface of said tubular electrical conductor means defining supply and return paths for dielectric liquid providing insulation for said electrical conductor means, and means for circulating said dielectric liquid along said supply and return paths. 2. The pump system of claim 1 wherein said pump units comprise a lowermost pump unit and at least one upper pump unit vertically spaced above said lowermost pump unit, wherein the electric motor of said at least one upper pump unit is located between said pipe means and said conductor means and includes a hollow drive shaft around said conductor means, and wherein said pipe means is constituted by a portion of said hollow drive shaft extending from said electric motor and having said impeller means connected thereto and by a pipe extending upwardly and downwardly from said hollow drive shaft portion. 3. The pump system of claim 2 wherein said dielectric liquid is a lubricant, and wherein one of said supply and return paths is between said pipe means and said electrical conductor means, whereby said electric motor is lubricated by said dielectric liquid. 4. The pump system of claim 2 wherein said tubular electrical conductor means comprises a plurality of concentric tubular conductors having solid insulation material therebetween, and wherein one of said supply and return paths is constituted by the interior of the inner tubular conductor and the other of said supply and return paths is defined between the outer tubular conductor and the said pipe means. 5. The pump system of claim 1 wherein the dielectric is a lubricant and wherein the electric motors of said pump units located in one of the supply and return paths, whereby said dielectric fluid is circulated through said electric motors. 6. The pump system of claim 1 further comprising a load-bearing outer pipe around the pump stack, and wherein liquid pumped by the pump units flows in the space between the load-bearing outer pipe and the pump stack. 7. The pump system of claim 1 suspended within a well casing, wherein there is a space between said pump stack and said well casing, and the liquid pumped by the pump units flows in said space. 8. The pump system of claim 7 further comprising locating means expandable between said well casing and said pump stack to locate said pump stack within said well casing. 9. The pump system of claim 8 wherein said locating means is expandable by pressure of said dielectric liquid. 10. The pump system of claim 1 further comprising in the lowermost of said pump units gas separator means driven by said dielectric liquid. 11. A pump system comprising: a pipe stack received within a well casing; a pump unit at the lower end of said pipe stack, said pump unit having impeller means, an electric motor driving said impeller means, inlet means and outlet means for fluid being pumped by said impeller means, and sealing means responsive to fluid pressure to effect a seal between said pump unit and said well casing at a position above said inlet means and below said outlet means; conductor means extending along said pipe stack for supplying power to said electric motor; a pipe surrounding said conductor means; means defining a fluid circuit having a supply path and a fluid return path along said pipe stack to said pump unit, means for circulating dielectric fluid on said circuit along said supply path to said pump unit and therefrom along said return path, said conductor means being tubular and having one of said supply and return paths along its outer surface and the other of said supply and return paths along its inner surface, whereby said dielectric fluid provides insulation for said conductor means; and means communicating said sealing means with said fluid circuit whereby said seal is effected in response to fluid pressure in said circuit. 12. The pump system of claim 11 wherein said circulating fluid is a lubricant and said pump unit motor is included in said fluid circuit. 13. The pump system of claim 11 further comprising at least one upper pump unit spaced along said pipe stack above said first-mentioned pump unit, said at least one upper pump unit having means responsive to fluid pressure in said fluid circuit to effect engagement between said upper pump unit and said well casing. 14. The pump system of claim 13 wherein said at least one upper pump unit comprises a motor, impeller means driven by said motor, a pipe having said motor and said fluid supply and return paths therewithin, and a sleeve around and spaced outwardly from said pipe for the passage of liquid pumped by said pump units between said pipe and said sleeve, and wherein said means responsive to fluid pressure comprises an expansible ring around said sleeve. 15. The pump system of claim 11 wherein said pipe stack further comprises at least one support means responsive to fluid pressure in said fluid circuit to effect supporting engagement between said pipe stack and said well casing at a location upwardly of said pump unit. 16. The pump system of claim 15 wherein said at least one support means is adapted to effect sealing engagement between said pipe stack and said well casing. 17. The pump system of claim 11 further comprising gas separator means in said pump unit, said gas separator means being driven by said fluid in said fluid circuit.