US3242360A - Submersible motor with plural cooling paths - Google Patents

Description

March 22, 1966 J. 'r. CARLE 3,242,360

SUBMERSIBLE MOTOR WITH PLURAL COOLING PATHS Filed Feb. 9, 1961 5 Sheets-Sheet 1 INVENTOR. JOSEPH T. CARLE BYWKW ATTORNEY.

J. T. CARLE March 22, 1966 SUBMERSIBLE MOTOR WITH PLURAL COOLING PATHS 5 Sheets-Sheet 2 Filed Feb. 9, 1961 G 3 G F 82 INVENTOR.

\IJOSEPH T. CARLE BY M g M ATTORNEY.

J. T. CARLE March 22, 1966 'SUBMERSIBLE MOTOR WITH PLURAL COOLING PATHS 5 Sheets-Sheet 5 Filed Feb. 9, 1961 ATTORNEY.

United States Patent 3,242,360 SUBMERSIBLE MOTOR WITH PLURAL COOLING PATHS Joseph T. Carle, Tulsa, Okla, assignor to Borg-Warner Corporation, Chicago, 111., a corporation of Illinois Filed Feb. 9, 1961, Ser. No. 88,223 1 Claim. (Cl. 31087) This invention relates to submersible electric motors adapted for insertion in deep wells for driving a pump therein and has for its principal object the provision of such motors with a new and improved means for circulating lubricating fluid therethrough for improved cooling, lubrication and better filtering.

A general object of this invention is to provide for better cooling, lubrication and filtering in the motor elements of motors which are limited in their diameter.

A still further object of this invention is to provide a submersible motor with means for directing cooling and lubricating fluid in primary and secondary circulating zones so that a major portion of the fluid is circulated through a heat exchanging zone for efiicient cooling .and filtering while a portion of this main circulation is further directed through the secondary zone for circulation throughout the remainder of the motor.

A still further object of this invention is to provide a submersible motor with means for circulating cooling and lubricating fluid in primary and secondary circulating zones and also to provide a means for circulating such fluid to and from a bearing for heat exchanger zone of a seal section used in connection with the motor; the latter zone forming a portion of or an adjunct to the secondary zone.

A still further object of this invention is to provide the motor with a means for directing cooling and lubricating fluid throughout the length of the rotor shaft and into the bearings thereof as well as along a portion of the outer periphery of the shaft intermediate the motor rotor providing for greater circulation of cooling fluid without a loss in horsepower and for a reduction in the number of hot spots in the motor and a reduction in the average operating temperature of the motor.

These and other objects of this invention will become apparent from the following description when taken in connection with the accompanying drawings in which:

FIG. 1 is an elevational view of the submersible motor constructed in accordance with the teachings of this invention;

FIG. 2 is a cross-sectional view taken along line 22 of FIG. 1 and looking in the direction of the arrows;

FIG. 3a is a partial elevatioual cross-sectional view taken along line 33 of FIG. 2 and illustrating to advantage the details of the upper portion of the submersible motor, FIG. 3a being only a portion of the entire motor by reason of the length thereof, for purposes of illustration in these drawings;

FIG. 3b is a partial elevational cross-sectional view taken along line 3-3 of FIG. 2 and showing a portion of the mid-section of the motor normally below that portion shown in FIG. 3a;

FIG. 30 is a partial elevational cross-sectional view taken along line 33 of FIG. 2 and illustrating the details of the lower portion of the motor; FIG. 3c being normally disposed below trail portion shown in FIG. 3b;

FIG. 4 is a cross-sectional partial schematic view taken along line 44 of FIG, 3 showing the connection means for the outside source of electrical power to be supplied to the electric motor;

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 3a, looking in the direction of the arrows, and illustrating to advantage the flow path of the cooling and lubricating fluid in the motor shaft;

3,242,360 Patented Mar. 22, 1966 FIG. 6 is a cross-sectional view taken along line 6-6 of FIG. 3a, looking in the direction of the arrows, and illustrating to advantage the centrifugal impeller mounted on the motor shaft for the circulation of the cooling and lubricating fluid; and

FIG. 7 is a cross-sectional view taken along line 77 of FIG. 3a, looking in the direction of the arrows, and illustrating to advantage a bearing shoe through which cooling and lubricating fluid flows.

As can be seen in FIG. 1, a submersible motor for insertion in deep wells, constructed in accordance with the teachings of this invention, is indicated in its entirety as 10.

Submersible motor 10 has an outer multi-part housing or casing 11, suitably sealed, as by threading and welding as shown at 12, 13 and 14 (FIGS. 31: and 30), so as to be fluid-tight to protect the inner motor elements from the fluid in the well. A stator 15, of the motor 10, is aflixed in any suitable manner to the inner side of the casing, as by snap rings 16 and 17, and a motor rotor 18, is maintained on a motor shaft 19 in any suitable manner as by a key 20. The motor 10 is supplied with electrical power from a suit-able and conventional outside source through wiring connection shown schematically at 21 (FIG. 4).

Shaft 19 is maintained for vertical operation in upper bearings, indicated in their entirety as 22 (FIG. 3a), intermediate bearings indicated in their entirety as 23 (one only showing 3b) and lower bearings indicated in their entirety as 24 (FIG. 30), so that, upon the application of electric power through the stator coils 25, the rotor 18 drives the shaft 19 to rotate a deep well pump (not shown). The upper end of the shaft 19 is externally splined, as illustrated at 26, to be connected to a suitable seal assembly (not shown) usually and conventionally interposed between the deep well pump vand the submersible motor. Since the deep well pump and the seal may be of conventional construction and do not form a part of the present invention, no further description thereof is deemed necessary herein.

As previously mentioned herein, an important feature of this invention is the provision of means for circulating cooling and lubricating fluid so that this fluid maintains the motor cool as well as properly lubricated. This is accomplished preferably by the circulation of the fluid into two flow paths-a primary flow path and a secondary flow path-and in such a manner that there is no reduction in the power output of the motor. This feature will now be described.

At the lower end of the shaft 19, a centrifugal impeller 27 (FIGS. 30 and 6) is suitably afiixed for rotation with the shaft 19, as by key 28. Outlet 29 of the impeller is in open communication with a passage 30 formed in a bearing housing 31. Passage 30 is in turn in open communication with a cylindrical passage or space 32 formed in part by the inner wall 33 of the casing 11 and in part by the outer wall 34 of a heat-resistant tube 35 of a smaller outer diameter than the inner diameter of the easing 11. This heat-resistant tube 35 is 'aflixed to the lower end of the bearing housing 31 and is formed of laminated plastic material or the like, of any suitable type, to insulate chamber 36 formed in part by such tube in cooperation with the bottom wall 37 of the casing 11. Thus, fluid pumped by the impeller 27 will travel from the outlet 29 into and through passage 30 and between, down the inner side wall 33 of the casing, and then into the inner chamber 36 through a plurality of ports 38 formed in the insulating tube 35. The casing 11 serves as a 'heat exchanger to cool the coolant as it travels through passages 30' and 32 to the chamber.

Chamber 36 is normally filled with the cooling and lubricating fluid, such as oil, for lubricating the various parts of the motor, bearings, and the like, and as clearly seen, the shaft 19 is provided with an internal concentric axial bore 40 throughout its length, the lower end of which is in open communication with the chamber 36.

In FIG. 3c it is to be noted that a chamber 41 is formed immediately below and in part by the rotor and stator and in part by the upper end of the bearing housing 31. There is also provided a pair of radial passages 42 which communicate with the shaft bore 40 and chamber 41. Thus, the cooling and lubricating fluid flowing up through the passage 40 will flow or be thrown by the rotation of the shaft, out the radial passages 42 into the chamber 41 where it communicates with a pair of vertical inlet passages 43 and 44 in the bearing housing 31. These passages in turn are in open communication with an inlet chamber 45 immediate the inlet 46 to the impeller 27. Passages 43 and 44 are suitably spaced from the shaft 19 to permit a conventional sleeve bearing 47 and bushing 48 of previously identified lower bushing 24 to be operatively interposed between the bearing housing 31 and the shaft, and to permit some circulation of the lubricating fluid to pass therebetween for proper lubrication and cooling.

Thus, it can be seen that, in this invention, there is a path of cooling and lubricating fluid from the impeller 27 past the 'heat exchanger formed by the casing 11, into the chamber 36 past a suitable filter 50 interposed operatively between the shaft bore 40 and the chamber 36 (filter 50 being shown in chamber), up the passage 40, out passages 42 into chamber 41, and thence down the inlet passages 43 and 44 into the inlet chamber 45 to be again recirculated by the impeller past the heat exchanger. This forms a primary path of circulation of fluid and provides a means of cooling and filtering a major portion of the oil during operation of the motor.

As will be seen, a secondary path of circulation is provided comprising a portion of fluid taken from the abovedescribed primary fluid so that the secondary circulation is always provided with a cool and filtered fluid without attempting to force the impeller to drive all of the cooling and lubricating fluid through the entire motor and back to the sump chamber. This maintains the coolant at an overall lower tempenature than could otherwise be accomplished.

Turning again to FIGS. 3a, 3b and 3c, it will be seen that the central shaft bore 40, above the radial passages 42, continues on throughout substantially the entire shaft up to and past the upper bearings 22. Intermediate the upper and lower hearings, pairs of radial passages 51 are provided in the shaft Where necessary to provide the intermediate bearings 23 with proper cooling and lubricating fluid thrown out by the rotating shaft from the passage 40. Intermediate bearings 23 comprise, in the embodiment shown, bushing 52 and a bearing ring 53, both of which have suitable means, such as openings 54, 55, to permit the flow of lubricant past the friction faces 56 and down between the stator or the rotor. Inasmuch as these hearings are of conventional construction, no further description thereof is deemed necessary. As the number of intermediate hearings will vary according to the length of the motor to give stability to the rotating parts, the number of such radial passages 51 will vary accordingly, one pair of such passages 51 being shown in FIG. 3b for the purposes of illustration.

Another pair of radial passages 57 are provided intermediate the intermediate bearing passages 51 to properly lubricate between the long bushing guide 58 and the shaft '19 and between the pair of bushings 60, 61, the former being provided between the upper part 62 of the casing and the shaft, as more clearly seen in FIG. 3a. Thus, there is a flow of fluid firomthese passages down the inner side of the bush ing guide and bushing and thence into upper chamber 63 provided by the casing, the upper end of the stator and rotor, and the upper casing part 62. The bushing guide and bushing are operatively held in their proper location by any suitable means, such as by snap ring 64.

Still another, but somewhat larger pair of radial passages 65 are provided in shaft 19 to communicate the shaft bore 40 with the upper bearings 22. Passages 65 communicate with a pair of radial passages 66 provided in a thrust ring 67 which is turn is maintained for roe tation with the shaft 19 by any suitable means; split ring 68, cap screws 70, lock ring 71 and key 72, being shown. Lubricating fluid is thrown out onto the bearing surfaces, onto thrust ring 67, and onto a non-rotating bearing shoe or ring 73 for proper lubrication and cooling thereof. Casing part 62 is provided with a cavity 74 enlarged radially opposite the bearing ring to receive the lubricant thrown out of the radial passage 66 and to permit the flow of such fluid down and through a plurality of such passages or slots 75 in the bearing ring; such slots being more clearly shown in FIG. 7. Slots 75 are in open communication with a pair of Iongitudinal passages or bores 76 and 77 formed in the casing part 62. Bores 76 and 77 are, in turn, in open communication with chamber 63 so that there is circulation of lubricant from the passage 40 in the shaft through the upper bearings 22. A suitable. restriction, as at 78, formed between the casing part 62 and the thrust bearing 67 is provided so that the main flow of fluid from the passages 65 and 66 will be downward towards the passages 75.

The shaft 19 is provided with a pair of longitudinal or coaxial grooves, diametrically opposed from one an-.

other, and, as more clearly shown in FIG. 5, at 90 from the key 20 as indicated at 80 and 81. These longitudinal grooves extend from that part of the shaft immediately above the rotor so that they open into the chamber 63 and continue below the rotor so that they open into the chamber 41, as more clearly shown in FIGS. 3a and 3c. Thus, fluid in the chamber 63 will flow down through these passages 80 and 81 between the shaft and the rotor to cool the same. Consequently, for proper lubrication and cooling it is not necessary to rely upon the spacing normally between the rotor and the stator, such spacing being indicated at 82, to supply cooling fluid through the motor. As taught by this invention, the motor may be properly cooled by the circulation of more fluid than heretofore possible without attempting to provide more circulation by enlarging the spacing or gap 82 to accomplish this purpose thus reducing the efficiency of the motor.

As can also be seen at the top of FIG. 3a, the bore 40 of the shaft 19 continues on through to be connected to a seal section (not shown) conventionally used in connection with the motor to isolate the motor from the Well fluid being pumped. As is conventional in such seal sections, a chamber is provided, as indicated schematically at 83. Such chamber in the embodiment shown is also connected with the motor by a passage illustrated schematically as connected to the bore 40 so that the cooling and lubricating fluid circulating in the secondary zone of the motor may enter this chamber and be circulated by such flow of fluid. Return flow may be provided by the passage, shown schematically at 85, so that fluid may pass through the restriction 78 to return tothe primary zone.

The chamber 83 has for its purpose a means for compensating for the expansion and contraction of fluid in the motor due to the heating and cooling thereof during operation of the motor. This chamber receives the expanded fluid during the running of the motor and permits the contracting fluid to return to the motor and also prevents any well fluid from entering the motor as it contracts.

As more particularly explained in the submersible seal disclosed and claimed in the co-pending patent application of Joseph T. Carle entitled Submersible Seal, Serial No. 88,096, now Patent No. 3,153,160, filed concurrently herewith, the chamber 83 may have other functions. In that application, such a chamber is a bearing and heat exchanger chamber so that an important bearing in the seal chamber may be lubricated and cooled by the circulation of fluid in this chamber and also this chamber functions as a heat exchanger to cool such fluid as it returns to the motor. Thus, by the provision of a means of circulating this fluid in the chamber during the operation of the pump, this fluid can be maintained at a lower temperature than could otherwise be accomplished to reduce the temperature of the bearing in the seal. It is to be noted, however, that while this motor is particularly adapted to be' used with the seal section disclosed and claimed in said co-pending application, this motor may be utilized with any seal section having such a chamber, or with any other means for allowing for the expansion and contraction of fluid during operation of the motor; chamber 83 as shown herein schematically, being illustrative of any expansion chamber which may be utilized.

From the above description it can be seen that there are two flow paths in the submersible motor constructed in accordance with the teachings of this invention; a primary flow path to provide a large circulation of circulant past the heat exchanger for greater cooling and better filtering and, the secondary flow path so constructed and arranged to utilize a :portion of the flow from the primary flow path through the remainder of the motor and a portion of the expansion chamber and with a further improvement of introducing cooling fluid down the outer periphery of the shaft on the inner side of the rotor to cool the latter without interference and/or loss of efliciency of the motor.

While the various parts herein have been described as upper and lower or in a right or left position, such description refers only to the relative position of the parts as shown in the drawings and is not intended to be a limitation of the invention; it being understood that the appended claim should be construed as broadly as the prior art will permit.

What is claimed is:

In a submersible motor, the combination of:

a motor casing;

a stator in said casing;

a motor shaft rotatably mounted in said casing;

a rotor mounted on and carried by said shaft;

an impeller having an inlet and an outlet adapted to circulate cooling and lubricating fluid within said motor casing;

spaced apart bearings rotatably supporting said shaft within said motor casing;

an internal longitudinal bore formed within said shaft providing means to circulate fluid therethrough;

radial passages formed in said shaft providing fluid communication from said internal longitudinal bore to said bearings;

a first chamber formed in said casing above said rotor;

a heat exchange chamber formed in said casing below said rotor;

a groove formed in said shaft extending a distance from a location above said rotor to a location below said rotor to provide fluid communication between said shaft and said rotor; and

a gap formed between said rotor and said stator;

said internal bore providing fluid communication from said heat exchange chamber to said first chamber;

said groove and said gap providing parallel fluid communication paths from said first chamber to said inlet;

said 'inlet being in fluid communication with said groove;

said heat exchange chamber being in fluid communication with said outlet.

References Cited by the Examiner UNITED STATES PATENTS 2,285,436 6/1942 Hoover 3l087 2,315,917 4/1943 Arutunolf 31087 2,568,548 9/1951 Howard 31087 2,736,825 2/ 1956 Hill 310-87 2,894,155 7/1959 Labastie 310-59 2,897,383 7/1959 Barrows et a1. 31068 2,938,131 5/1960 Maynard 31087 2,951,165 8/1960 Arutunoff 310-87 X 2,974,240 3/ 1961 Arutunoif 310-87 FOREIGN PATENTS 1,087,959 3/ 1955 France.

ORIS L. RADER, Primary Examiner.

MILTON O. HIRSHFIELD, Examiner.

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