Canned motor pump for use at high temperatures

• US 4,652,218 A
• Filed: 12/06/1985
• Issued: 03/24/1987
• Est. Priority Date: 01/16/1981
• Status: Expired due to Term

• Current Assignee: Nikkiso Company Limited
• Original Assignee: Nikkiso Company Limited
• Inventors: Ohki, Hiroshi, Tsutsui, Toshiaki
• Primary Examiner(s): Croyle, Carlton R.
• Assistant Examiner(s): Stout, Donald E.
• Application Number:
  US06/805,876
• Time in Patent Office: 473 Days
• Field of Search: 417/368, 417/370, 417/369, 417/366, 417/371, 417/372, 310/43, 310/87, 310/208, 310/214, 310/215, 252/567, 428/324, 428/369, 428/370, 428/450, 106/DIG. 3, 106/287.1, 174/110 R, 174/110 S, 264/61, 501/151, 501/154
• US Class Current: 417/368
• CPC Class Codes: F04D 13/064 Details of the magnetic circuit
• CPC Class Codes: H01B 3/04 mica
• CPC Class Codes: H01B 7/292 using material resistant to heat
• CPC Class Codes: H02K 3/32 Windings characterised by the shape, form or construction of the insulation
• CPC Class Codes: H02K 5/128 using air-gap sleeves or air-gap discs

Abstract

A canned motor pump is adapted for use at high temperatures and enables generated heat from the motor to be absorbed in a treating fluid or liquid upon circulation through the motor thereby conserving heat values in the treating fluid or liquid. The canned motor pump can circulate high temperature treating fluids, or liquids through the canned motor portion without damaging the coils of the motor because of a ceramic-like high temperature insulation used for the electrical field windings, which insulation is provided by mixing a silicone resin, synthetic fluoro-mica and a devitrified mica glass and impregnating the electrical winding coils with such material, whereafter the material is cured and then subjected to an elevated temperature above 300° C. to form the ceramic-like insulation.

Claims

1. A canned motor pump for use with high temperature process fluids having temperatures above 200°

C., comprising a canned motor having a rotor assembly including a rotor shaft to which an impeller is secured, said impeller extending into a chamber of the pump having a suction side and a discharge side, spaced apart rotor chambers at opposite ends of said rotor assembly, said rotor chambers comprising a front rotor chamber and a rear rotor chamber, and means forming part of the pump defining a fluid circulating path for circulating a portion of the fluid in the pump into and through the rotor chambers forming part of said fluid circulating path, one of said rotor chambers communicating with said suction side of the pump and another of said rotor chambers communicating with the discharge side of the pump whereby said portion of the fluid flowing into and through the rotor chambers effectively cools the canned motor, and to resist breakdown of the canned motor when subjected to operating current and high temperature fluids, said canned motor has field windings impregnated with a ceramic-like insulating material which is the reaction product of an impregnant comprising a suspension of a silicone resin and a synthetic fluoro-mica in an organic solvent, said reaction product being derived on subjecting the impregnant, after curing, to temperatures above 300°

C. to thermally decompose the silicone resin, evidenced by loss of organic radicals from the silicone resin with resulting conversion of the resin to polysiloxane which is exposed to a fluoro-compound vaporized from said synthetic fluoro-mica at the same temperature as that at which decomposition of the silicone resin occurs.

2. The canned motor pump according to claim 1, wherein the synthetic fluoro-mica contains devitrified mica glass.

3. The canned motor pump according to claim 2, wherein the silicone resin comprises a polyphenylmethyl silicone.

4. The canned motor pump according to claim 3, wherein the silicone resin is KR-282 and the synthetic fluoro-mica is PDM KM 325.

5. The canned motor pump according to claim 3, wherein said polyphenylmethyl silicone has the following basic structure ##STR2##

6. The canned motor pump of claim 1, wherein the reaction product of polysiloxane and synthetic fluoro-mica has a dielectric strength against ground of at least 4.32 and between phases of 3.92 and a modulus of elasticity of between 4 and 5 thousand Kg/μ

m.

7. The canned motor pump according to claim 1, wherein the pump and the canned motor are interconnected by an adapter formed with a passage for interconnecting canned motor passages with pump passages.

8. The canned motor pump of claim 7, wherein said canned motor includes a stator, said front rotor chamber communicating via said adapter with a peripheral portion of the impeller at a discharge side of the pump;

and the rear rotor chamber communicates with the front rotor chamber via a gap between said rotor and stator, said rear rotor chamber also communicating with the suction side of the pump via an internal conduit formed in the rotor shaft.

9. The canned motor pump of claim 8, wherein a liner disc having an opening is arranged between said suction side of the pump and said adapter and forming an extension dividing said adapter passage into two parts, one communicating with said opening in the liner disc and the other part with that end of the internal conduit nearest said front rotor chamber.

10. The canned motor pump of claim 1, wherein the fluid circulating path includes an external conduit connected at one end thereof with the discharge side of the pump, an opposite end of the external conduit communicating with the rear rotor chamber, said front rotor chamber in addition to communicating with said rear rotor chamber through said gap also communicating with said pump chamber on a back side of said impeller.

11. The canned motor pump of claim 1, wherein the fluid circulatory system includes an auxiliary pump chamber disposed between said chamber into which said impeller extends and said front rotor chamber and communicating with said chamber into which said impeller extends on a back side of said impeller, said auxiliary pump chamber also communicating at its delivery side with the rear rotor chamber via an external conduit and having a suction side communicating with said front rotor chamber.

12. The canned motor pump according to claim 1, wherein the field windings of the motor comprise a nickel-plated copper wire coated with a glass insulating material, a wedge of laminated mica bonded with an inorganic material, a flexible insulating sheet of laminated mica, silicone resin adhesive and an insulating impregnating material comprising a silicone resin filled with synthetic fluorinated mica.

13. The canned motor pump according to claim 1, further comprising thermal insulation surrounding the periphery of said canned motor.