High-temperature motor pump and method for operating thereof

• US 5,882,182 A
• Filed: 03/18/1997
• Issued: 03/16/1999
• Est. Priority Date: 03/18/1996
• Status: Expired due to Fees

• Current Assignee: Ebara Corporation
• Original Assignee: Ebara Corporation
• Inventors: Kato, Hiroyuki, Honda, Shuichiro
• Primary Examiner(s): Freay, Charles G.
• Assistant Examiner(s): TYLER, CHERYL JACKSON
• Application Number:
  US08/819,939
• Time in Patent Office: 728 Days
• Field of Search: 417/228, 417/366, 417/372, 417/423.8
• US Class Current: 417/366
• CPC Class Codes: F04D 29/588 cooling or heating the machine F04D29/5886, F04D29/5893 take precedence
• CPC Class Codes: H02K 2205/12 Machines characterised by means for reducing windage losses or windage noise
• CPC Class Codes: H02K 5/128 using air-gap sleeves or air-gap discs
• CPC Class Codes: H02K 9/197 in which the rotor or stator space is fluid-tight, e.g. to provide for different cooling media for rotor and stator

Abstract

A high-temperature motor pump is operated by a method wherein coolant is supplied in a manner to maintain the temperature thereof sufficiently high to keep its viscosity at a low level for smoothly flowing in a narrow gap between a rotor and a stator. Thus, the coolant performs a cooling function without frictional loss, and thereby the motor pump is stably operated with little energy loss.

Claims

1. A method of operating a motor pump including a pump portion for pumping a liquid, a motor portion for rotating said pump portion by way of a common rotation shaft and including a stator and a rotor, and a casing housing said pump portion and said motor portion, said method comprising:

providing a coolant to a gap between said stator and said rotor; and

controlling the temperature of said coolant in said gap to be higher than a predetermined temperature necessary to maintain the viscosity of said coolant in said gap at a level to reduce frictional loss between said rotor and said stator.

2. A method as claimed in claim 1, wherein said predetermined temperature is lower than a maximum operating temperature of said motor portion and is a temperature at which a kinematic viscosity coefficient of said coolant is less than 1/3 of the kinematic viscosity coefficient of said coolant at room temperature.

3. A method as claimed in claim 1, wherein said predetermined temperature is higher than the evaporation temperature of said coolant.

4. A method as claimed in claim 1, wherein said coolant is of a material the same as said liquid.

5. A method as claimed in claim 1, wherein said coolant comprises a portion of said liquid.

6. A method as claimed in claim 1, wherein said controlling comprises adjusting the flow rate of said coolant into said gap.

7. A method as claimed in claim 1, wherein said controlling comprises adjusting the temperature of said coolant supplied to said gap.

8. A method as claimed in claim 7, further comprising detecting said temperature of said coolant in said gap by a sensor located at said gap and generating a signal representative of the detected temperature, and wherein said adjusting is in response to said signal.

9. A method as claimed in claim 1, further comprising cooling a part of said motor portion with said coolant, and then supplying said coolant into said gap.

10. A method as claimed in claim 9, wherein said cooling evaporates said coolant, and said supplying comprises passing said coolant in a gaseous state into said gap.

11. A method as claimed in claim 1, wherein said motor portion has spaces at opposite axial ends thereof, and further comprising circulating coolant between said spaces through a cooling pipe located outwardly of said casing, and cooling the thus circulating coolant.

12. A high-temperature pump comprising:

a pump portion for pumping a liquid;

a motor portion for driving said pump portion, said motor portion including a stator and a rotor with a gap therebetween;

a rotation shaft for transmitting rotation from said motor portion to said pump portion;

a casing housing said pump portion, said motor portion and said rotation shaft;

a coolant passage in said casing for flowing a coolant to said gap;

a temperature sensor for sensing temperature in said gap and for generating a signal representative thereof; and

a controller receiving said signal and operable in response thereto to control the temperature of the coolant in said gap to be higher than a predetermined temperature necessary to maintain the viscosity of the coolant in said gap at a level to reduce frictional loss between said stator and said rotor.

13. A pump as claimed in claim 12, wherein said controller includes a valve for adjusting the flow rate of the coolant.

14. A pump as claimed in claim 12, wherein said controller includes a heat exchanger for adjusting the temperature of the coolant.

15. A pump as claimed in claim 12, wherein said predetermined temperature is lower than a maximum operating temperature of said motor portion and is a temperature at which a kinematic viscosity coefficient of the coolant is less than 1/3 of the kinematic viscosity coefficient of the coolant at room temperature.

16. A pump as claimed in claim 12, wherein said predetermined temperature is higher than the evaporation temperature of the coolant.

17. A pump as claimed in claim 12, further comprising a branch passage extending from a pump outlet to said coolant passage for supplying pumped liquid to said coolant passage as the coolant.

18. A pump as claimed in claim 12, wherein said motor portion has spaces at opposite axial ends thereof, and further comprising a cooling pipe extending between said spaces and located outwardly of said casing for circulating the coolant between said spaces.

19. A high-temperature pump comprising:

a pump portion for pumping a liquid;

a motor portion for driving said pump portion, said motor portion including a stator and a rotor with a gap therebetween;

a rotation shaft for transmitting rotation from said motor portion to said pump portion;

a casing housing said pump portion, said motor portion and said rotation shaft;

a coolant passage in said casing for flowing a coolant to said gap;

said casing having therein a stator housing portion including spaces housing opposite edge portions of stator coils; and

a cooling pipe extending between said spaces and located outwardly of said casing for circulating the coolant directly between said spaces without passing the coolant through a heat exchanger.

20. A pump as claimed in claims 19, further comprising a controller operable to control the temperature of the coolant in said gap to be higher than a predetermined temperature necessary to maintain the viscosity of the coolant in said gap at a level to reduce frictional loss between said stator and said rotor.

21. A pump as claimed in claim 20, wherein said predetermined temperature is lower than a maximum operating temperature of said motor portion and is a temperature at which a kinematic viscosity coefficient of the coolant is less than 1/3 of the kinematic viscosity coefficient of the coolant at room temperature.

22. A pump as claimed in claim 20, wherein said predetermined temperature is higher than the evaporation temperature of the coolant.

23. A pump as claimed in claim 20, wherein said controller is operable to adjust the flow rate of the coolant in said gap.

24. A pump as claimed in claim 20, wherein said controller is operable to adjust the temperature of the coolant in said gap.

25. A pump as claimed in claim 19, further comprising a branch passage extending from a pump outlet to said coolant passage for supplying pumped liquid to said coolant passage as the coolant.

26. A high-temperature pump comprising:

a pump portion for pumping a liquid;

a motor portion for driving said pump portion, said motor portion including a stator and a rotor with a gap therebetween;

a rotation shaft for transmitting rotation from said motor portion to said pump portion;

a casing housing said pump portion, said motor portion and said rotation shaft;

a coolant passage in said casing for flowing a coolant to said gap;

a temperature sensor for sensing temperature in said gap and for generating a signal representative thereof;

a controller receiving said signal and operable in response thereto to control at least one of the flow rate of the coolant and the temperature of the coolant;

said motor portion having spaces at opposite axial ends thereof; and

a cooling pipe extending between said spaces and located outwardly of said casing for circulating the coolant directly between said spaces without passing the coolant through a heat exchanger.