Title of Invention

Liquid Filled Electric Motor

Abstract Liquid filled electric motor. The motor 1 comprises a tubular housing (3) closed at the ends with a bottom end shield (7) and a top end shield (6) and filled with a liquid coolant cum lubricant (4). A stator assembly (2) is fitted in the tubular housing and a rotor assembly (5) is rotatably disposed within the stator assembly and having a shaft (5a) rotatably held on the bottom end shield and in the top end shield with bearings (8a, 8b), The top end of the shaft protrudes out through the top end shield with the clearance therebetween sealed with a seal (9). The motor further comprises a funnel shaped partition sleeve (10) disposed between the rotor assembly and stator assembly in spaced apart relationship with each other to partition the liquid in the tubular housing into an active zone and a passive zone. The lower end of the sleeve is wide and fixed on the bottom end shield and provided with liquid recirculation openings (12a) therethrough. The upper end of the sleeve extends upto the upper end of the stator assembly. A baffle (11) is disposed at the upper end of the sleeve and fitted to the top end of the shaft. The shaft is provided with liquid recirculation openings (12b, 12c) therethrough at the bottom end thereof and at the top end thereof above the baffle. The liquid recirculation openings in the wide lower end of the partition sleeve facilitate recirculation of the liquid between the active and passive zones. The recirculation openings at the bottom end of the shaft facilitate recirculation of the liquid in the active zone and the recirculation openings at the top end of the shaft facilitate recirculation of the liquid in the passive zone. The baffle rotating with the shaft isolates the active zone from the passive zone and facilitates recirculation of the liquid in the active zone. Also a submersible pump comprising the motor. (Fig 1).
Full Text FORM 2
THE PATENTS ACT, 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
Liquid filled electric motor
APPLICANTS
CROMPTON GREAVES LIMITED, CG House, Dr Annie Besant Road, Prabhadevi, Mumbai 400025, Maharashtra, India, an Indian Company
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed :







FIELD OF INVENTION
This invention relates to a liquid filled electric motor. BACKGROUND DESCRIPTION
Liquid filled electric motors are used for driving submersible pumps which
are usually used to pump out liquids such as oil or water from bore wells. A
typical liquid filled electric motor comprises a stator assembly fitted in a
tubular housing closed at the ends with a bottom end shield and a top end
shield and filled with a liquid coolant cum lubricant such as water, glycerin,
or off. A rotor assembly having a shaft is rofatabfy disposed within the stator
assembly with its shaft rotatably held in the top end shield and on the
bottom end shield using bearings. The top end of the shaft protrudes out
through the top end shield and the clearance between the top end of the shaft
and top end shield is sealed with a seal. In a submersible pump and liquid
filled electric motor combination, the pump is mounted on the tubular
housing (motor housing) at the top thereof with the impeller of the pump
mounted on the top end of the shaft. During operation of the motor, the rotor
rotates to deliver power. Due to rotation of the rotor, the entire liquid in the
tubular housing is churned. The stator and the stator windings offer
resistance to the liquid being churned. Power utilized in churning the liquid
leads to churning losses thereby reducing power output and efficiency of the

motor. Due to the force of churning and the turbulence created in the motor housing, the liquid in the motor housing leaks out through the seal between the top end shield and the top end of the shaft of the motor. Besides, air outside the tubular housing enters the housing through the seal due to the differential pressure in the housing and outside the housing. The more intense the agitation of the liquid, the greater the leakage of the liquid and entry of air into the housing. The air form air bubbles around the bearings thereby reducing the surface area of contact between the bearings and the liquid. This results in improper and insufficient lubrication of the bearings and premature failure thereof leading to frequent replacement of the bearings and increase in the maintenance cost thereof.
OBJECTS OF INVENTION
An object of the invention is to provide a liquid filled electric motor, which reduces churning losses and improves power output and efficiency of the motor.
Another object of the invention is to provide a liquid filled electric motor, which prevents premature failure of the bearings of the motor thereby

increasing the life of the bearings and avoiding frequent replacement and maintenance cost thereof.
Another object of the invention is to provide a submersible pump comprising a liquid filled electric motor, which reduces churning losses and improves power output and efficiency of the motor.
Another object of the invention is to provide a submersible pump comprising a liquid filled electric motor, which prevents premature failure of the bearings of the motor thereby increasing the life of the bearings and avoiding frequent replacement and maintenance cost thereof.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention there is provided a liquid filled electric motor comprising a tubular housing closed at the ends with a bottom end shield and a top end shield and filled with a liquid coolant cum lubricant, a stator assembly fitted in the tubular housing and a rotor assembly rotatably disposed within the stator assembly and having a shaft rotatably held on the bottom end shield and in the top end shield with bearings, the top end of the shaft protruding out through the top end shield with the clearance

therebetween sealed with a seal, wherein the motor further comprising a funnel shaped partition sleeve disposed between the rotor assembly and stator assembly in spaced apart relationship with each other to partition the liquid in the tubular housing into an active zone and a passive zone, the lower end of the sleeve being wide and fixed on the bottom end shield and provided with liquid recirculation openings therethrough, the upper end of the sleeve extending upto the upper end of the stator assembly and a baffle disposed at the upper end of the sleeve and fitted to the top end of the shaft, the shaft being provided with liquid recirculation openings therethrough at the bottom end thereof and at the top end thereof above the baffle, the liquid recirculation openings in the wide lower end of the partition sleeve facilitating recirculation of the liquid between the active and passive zones, the recirculation openings at the bottom end of the shaft facilitating recirculation of the liquid in the active zone and the recirculation opening at the top end of the shaft facilitating recirculation of the liquid in the passive zone and the baffle rotating with the shaft isolating the active zone from the passive zone and facilitating recirculation of the liquid in the active zone.

According to the invention there is also provided a submersible pump comprising a liquid filled electric motor having a tubular housing closed at the ends with a bottom end shield and a top end shield and filled with a liquid coolant cum lubricant, a stator assembly fitted in the tubular housing and a rotor assembly rotatably disposed within the stator assembly and having a shaft rotatably held on the bottom end shield and in the top end shield with bearings, the top end of the shaft protruding out through the top end shield with the clearance therebetween sealed with a seal, wherein the motor further comprising a funnel shaped partition sleeve disposed between the rotor assembly and stator assembly in spaced apart relationship with each other to partition the liquid in the tubular housing into an active zone and a passive zone, the lower end of the sleeve being wide and fixed on the bottom end shield and provided with liquid recirculation openings therethrough, the upper end of the sleeve extending upto the upper end of the stator assembly and a baffle disposed at the upper end of the sleeve and fitted to the top end of the shaft, the shaft being provided with liquid recirculation openings therethrough at the bottom end thereof and at the top end thereof above the baffle, the liquici recirculation openings in the wide lower end of the partition sleeve facilitating recirculation of the liquid between the active and passive zones, the recirculation openings at the bottom end of the shaft

facilitating recirculation of the liquid in the active zone and the recirculation opening at the top end of the shaft facilitating recirculation of the liquid in the passive zone and the baffle rotating with the shaft isolating the active zone from the passive zone and facilitating recirculation of the liquid in the active zone.
The following is a detailed description of the invention with reference to the accompanying drawings, in which the sole Fig 1 is a schematic crosssectional view of a liquid filled electric motor according to an embodiment of the invention. The liquid filled electric motor 1 as illustrated in Fig 1 of the accompanying drawings comprises a stator assembly 2 fitted in a tubular housing 3 filled with a liquid coolant cum lubricant such as water marked 4. The core and windings of the stator are marked 2a and 2b. A rotor assembly 5 is rotatably disposed within the stator assembly with its shaft 5a rotatably held in the top endshield 6 and on the bottom end shield of the motor using bearings 8a and 8b, respectively. The top end of the shaft protrudes out through the top end shield. 9 is a seal between the top end of the shaft and top end shield of the motor. 10 is a partition sleeve disposed over the rotor assembly 5 in spaced apart relationship with the rotor assembly and stator assembly 2 of the motor. The

partition sleeve is funnel shaped and its wide end 10a forms the lower end thereof and is fixed on the bottom end shield 7 of the motor. The upper end of the sleeve extends upto the upper end of the stator assembly. 11 is a disc shaped baffle disposed at the upper end of the sleeve and fitted to the top end of the shaft of the rotor. The lower wide end of the sleeve is provided with liquid recirculation openings 12a therethrough. The shaft is provided with liquid recirculation openings 12b and 12c therethrough at the bottom end thereof and at the top end thereof above the baffle, respectively.
During operation of the motor, the rotor rotates to deliver power. Due to rotation of the rotor, the liquid within the sleeve is intensely agitated and churned, whereas the churning effect in the liquid outside the sleeve is considerably reduced. The sleeve thus partitions the liquid in the housing into an active zone within the sleeve and a passive zone outside the sleeve. The openings 12a at the lower end of the sleeve allow the liquid to recirculate therethrough between the active zone within the sleeve and the passive zone outside the sleeve so as to cool the stator core and windings. The recirculation openings 12c at the bottom of the shaft facilitate recirculation of the liquid in the active zone. The recirculation openings 12b at the top end of the shaft facilitate recirculation of the liquid in the passive

zone. The baffle rotates with the shaft and isolates the active zone from the passive zone and also facilitates recirculation of the liquid in the active zone. As only a reduced quantity of the liquid within the sleeve is subjected to intense churning as compared to the entire liquid body in the housing in the conventional case, the force for churning the reduced quantity of the liquid is reduced and churning losses are also reduced thereby increasing power output and efficiency of the motor. Since the churning of the liquid is practically restricted to the active zone surrounding the rotor assembly within the partition sleeve and the force of churning is reduced, leakage of the liquid through the seal 9 between the top end shield and top end of the shaft is also reduced. Therefore, entry of atmospheric air into the motor housing through the seal due to differential pressure in the housing and outside atmosphere is also reduced. Formation of air bubbles between the end shield bearings is reduced and the reduced amount of air bubbles remain more and less at the top surface of the housing as indicated by 13. Therefore the surface area of contact between the bearings and coolant cum lubricant is almost maintained. Lubrication of bearings is not adversely affected thereby preventing premature failure of the bearings. The life of the bearings is improved and their frequent replacement and maintenance cost are avoided. Because of the recirculation of the liquid,

heat dissipation across the liquid in the motor housing is improved. The stator and stator windings are effectively cooled and the cooling efficiency of the motor is improved.
The baffle member can be corrugated and the openings in the shaft and at the lower end of the partition sleeve may be of any geometry and their numbers may vary. Such variations / modifications of the invention are obvious to those skilled in the art and are to be construed and understood to be within the scope of the invention.

We Claim:
1) A liquid filled electric motor comprising a tubular housing closed at the ends with a bottom end shield and a top end shield and filled with a liquid coolant cum lubricant, a stator assembly fitted in the tubular housing and a rotor assembly rotatably disposed within the stator assembly and having a shaft rotatably held on the bottom end shield and in the top end shield with bearings, the top end of the shaft protruding out through the top end shield with the clearance therebetween sealed with a seal, wherein the motor further comprising a funnel shaped partition sleeve disposed between the rotor assembly and stator assembly in spaced apart relationship with each other to partition the liquid in the tubular housing into an active zone and a passive zone, the lower end of the sleeve being wide and fixed on the bottom end shield and provided with liquid recirculation openings therethrough, the upper end of the sleeve extending upto the upper end of the stator assembly and a baffle disposed at the upper end of the sleeve and fitted to the top end of the shaft, the shaft being provided with liquid recirculation openings therethrough at the bottom end

thereof and at the top end thereof above the baffle, the liquid recirculation openings in the wide lower end of the partition sleeve facilitating recirculation of the liquid between the active and passive zones, the recirculation openings at the bottom end of the shaft facilitating recirculation of the liquid in the active zone and the recirculation opening at the top end of the shaft facilitating recirculation of the liquid in the passive zone and the baffle rotating with the shaft isolating the active zone from the passive zone and facilitating recirculation of the liquid in the active zone.
2) A submersible pump comprising a liquid filled electric motor having a tubular housing closed at the ends with a bottom end shield and a top end shield and filled with a liquid coolant cum lubricant, a stator assembly fitted in the tubular housing and a rotor assembly rotatably disposed within the stator assembly and having a shaft rotatably held on the bottom end shield and in the top end shield with bearings, the top end of the shaft protruding out through the top end shield with the clearance therebetween sealed with a seal, wherein the motor further Comprising a funnel shaped partition sleeve disposed between the rotor assembly and stator

assembly in spaced apart relationship with each other to partition the liquid in the tubular housing into an active zone and a passive zone, the lower end of the sleeve being wide and fixed on the bottom end shield and provided with liquid recirculation openings therethrough, the upper end of the sleeve extending upto the upper end of the stator assembly and a baffle disposed at the upper end of the sleeve and fitted to the top end of the shaft, the shaft being provided with liquid recirculation openings therethrough at the bottom end thereof and at the top end thereof above the baffle, the liquid recirculation openings in the wide lower end of the partition sleeve facilitating recirculation of the liquid between the active and passive zones, the recirculation openings at the bottom end of the shaft facilitating recirculation of the liquid in the active zone and the recirculation opening at the top end of the shaft facilitating recirculation of the liquid in the passive zone and the baffle rotating with the shaft isolating the active zone from the passive zone and facilitating recirculation of the liquid in the active zone


Documents:

303-MUM-2005-ABSTRACT(13-8-2010).pdf

303-mum-2005-abstract(granted)-(3-1-2011).pdf

303-mum-2005-abstract.doc

303-mum-2005-abstract.pdf

303-mum-2005-cancelled pages(13-8-2010).pdf

303-MUM-2005-CLAIMS(AMENDED)-(13-8-2010).pdf

303-mum-2005-claims(granted)-(3-1-2011).pdf

303-mum-2005-claims.doc

303-mum-2005-claims.pdf

303-MUM-2005-CORRESPONDENCE(22-10-2008).pdf

303-mum-2005-correspondence(23-4-2008).pdf

303-MUM-2005-CORRESPONDENCE(23-4-2009).pdf

303-MUM-2005-CORRESPONDENCE(27-7-2009).pdf

303-MUM-2005-CORRESPONDENCE(3-12-2010).pdf

303-MUM-2005-CORRESPONDENCE(4-12-2009).pdf

303-mum-2005-correspondence(ipo)-(5-1-2011).pdf

303-mum-2005-correspondence-received-210305.pdf

303-mum-2005-correspondence-received.pdf

303-mum-2005-descripiton (complete).pdf

303-mum-2005-description(granted)-(3-1-2011).pdf

303-MUM-2005-DRAWING(13-8-2010).pdf

303-mum-2005-drawing(granted)-(3-1-2011).pdf

303-mum-2005-drawings.pdf

303-mum-2005-form 1(30-5-2007).pdf

303-mum-2005-form 18(7-12-2007).pdf

303-mum-2005-form 2(granted)-(3-1-2011).pdf

303-MUM-2005-FORM 2(TITLE PAGE)-(13-8-2010).pdf

303-mum-2005-form 2(title page)-(complete)-(21-3-2005).pdf

303-mum-2005-form 2(title page)-(granted)-(3-1-2011).pdf

303-mum-2005-form-1.pdf

303-mum-2005-form-2.doc

303-mum-2005-form-2.pdf

303-mum-2005-form-26.pdf

303-mum-2005-form-3.pdf

303-MUM-2005-PUBLICATION REPORT(22-10-2008).pdf

303-MUM-2005-REPLY TO EXAMINATION REPORT(13-8-2010).pdf

303-MUM-2005-SPECIFICATION(AMENDED)-(13-8-2010).pdf

303-MUM-2005-SPECIFICATION(MARKED COPY)-(13-8-2010).pdf

abstract1.jpg


Patent Number 245121
Indian Patent Application Number 303/MUM/2005
PG Journal Number 01/2011
Publication Date 07-Jan-2011
Grant Date 03-Jan-2011
Date of Filing 21-Mar-2005
Name of Patentee Crompton Greaves Ltd
Applicant Address CG House, Dr Annie Besant Road,Prabhadevi, Mumbai.
Inventors:
# Inventor's Name Inventor's Address
1 Shanmugam Venkatachalam Ravi Crompton Greaves Ltd, Corporate R & D and Quality Analytical Laboratory, Kanjur Marg(E), Mumbai 400042,
PCT International Classification Number F04D13/08 H02K5/12
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA