US2270666A - Deep well pump - Google Patents

Description

Jan. 20, 1942. A. ARUTUNOFF DEEP WELL` PUMP 2 Sheets-Sheet l Filed NOV. 4, 1957 Jan. 20, 1942. A ARUTUNOFF DEEP WELL PUMP 2 Sheets-Sheet 2 Filed Nov. 4, 1937 miv, f

Patented `ian.. 20, i942 DEEP WELL PUMP Armais Arutunoi, Bartlesville, Okla., assignor to Reda Pump Company, Bartlesville, Okla., a

corporation of Delaware Application November 4, 1937, `Serial No. 172,761

Claims.

My invention relates to deep well pumps and more particularly to an electrically driven, submergible, deep Well pump adapted to be positioned at the bottom of a deep well.

A deep well, such as an oil well or a water well must necessarily be of comparatively small diameter. Many oil Wells, for example, are equipped with a well casing, having a seven inch diameter. The wells may vary in depth over wide limits. Some are comparatively shallow,

being about one thousand feet in depth. Others are extremely deep, being over seven thousand feet. The lifting of oil or water through such comparatively great distances necessitates a pump having a high discharge pressure. I have been able to obtain pressures in excess of 3300 pounds per square inch by a multistage, centrifugal pump of my invention. Due to the small diameter, a large number of stages must be employed and the impeller elements must be rotated at comparatively high speed. i The thrust of such an assembly under the speeds involved requires a rugged construction and a novel means of lubrication. It is extremely important that the bearings be protected against the deleterious effects of penetration of liquids, in the well in which the pump is submerged, into the bearings. I have found it necessary to employ pumps having as many as three hundred stages. The number of stages, of course, will vary, depending on the type of impeller employed and the height through which the fluid is to be lifted and the type of fluid being pumped. In all cases, however, it is necessary to use a comparatively large number of stages. The manufacture of a pump of this nature is an extremely dimcult task.

The pump must be placed in the well in a vertical position and the thrust bearing must resist at least the thrust against the area of the shaft occasioned by the high pressure of the discharged oil. If the discharge pressure, for example, is 3300 pounds per square inch and a shaft an inch in diameter is employed, the thrust bearing must carry a load of approximately 2,700 pounds. Rotating at high speeds, it will be seen that the thrust bearing is doing yeoman service.

inasmuch as the positioning of a pump at the -bottom of a well is a time consuming task,'pro vision must be made not only to adequately lubricate the thrust bearing but also to prevent the seepage of uids from the well, which would deleteriously affect the bearing.

One object of my invention is to provide a novel pump assembly wherein a multi-stage, centrifugal M pump may be manufactured having any desired number of stages.

Another object of my invention is to provide a multistage, centrifugal pump adapted to be submerged in a deep well in which each impeller carries its own thrust.

Another object of my invention is to provide a thrust bearing assembly provided with combined means to lubricate the assembly and to prevent the seepage of deleterious uids from the well to the bearing and to the motor.

Other and further objects of my invention will appear from the following description.

In general, my invention contemplates the provision of a pump in which a plurality of diffusers and impellersare assembled in an elongated casing, each of the diffusers and impellers being of identical design, whereby any desired number of stages may be easily achieved, in which the impellers are constrained to rotate with the shaft but are free to move axially thereof, whereby each individual impeller thrust is carried by respective diffuser sections instead of being transmitted to the shaft. The shaft is driven =by an electric motor between which and the pump assembly is interposed aprotector adapted to seal the motor against fluids from the well. interposed between the protector and the pump I disposed a thrust bearing and employ a viscous lubricant such as a grease as a sealing fluid whereby the sealing uid is adapted to exercise a combined protecting action against seepage and lubricating action upon the thrust bearing.

In the accompanying drawings which form part of the instant specification and are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views:

Figure 1 is a diagrammatic view of a cross section of a well provided with a pump unit of my invention.

Figure 2 is an enlarged sectional elevation with parts broken away, of my motor-protector-pump assembly.

Figure 3 is an enlarged sectional view of a pump embodying my invention.

Figure 4 is a perspective view, showing the `details of assembly.

Figure 5 is a sectional View of a thrust bearing of my invention.

' Figure 6 is a sectional View of the protector of my invention.

More particularly referring now to the drawings, the well is provided with a casing I which is normally closed by a. casinghead 2. Eduction tubing 3 for the removal off liquid from the well is provided. 'I'he eduction tubing receives the discharge of pump 4. The pump takes suction through screen 5 and is driven by an electric motor 6; A protector 1 is interposed between the pump 4 and the motor 6. The motor proper forms no part of the instant invention and is furnished electrical energy for its operation through an electric cable 3 which is normally stored upon a cable reel 9. A control panel Ill may contain an entrance switch II, an ammeter I2, a magnetic switch I3, and the customary fuses, lightning arresters, and the like. A transformer I4 is provided, the output of which is impressed upon the motor through the cable 8.

Referring now to Figure 3, which shows the pump proper, the pump comprises an elongated casing I5, closed at its upper end by a head I6, to which the eduction tubing 3 is secured. The lower end of the casing I5 is closed by a member I1, provided with intake passages I3 which are surrounded by a screen I9. The member I1 is provided with a recess in which is seated an impeller adapter 20 which carries a down-thrust washer 2l on which is seated an impeller 22. Surrounding the impeller 22 is a lower spacer 23. The up-thrust washer 24 is interposed between impeller 22 and diffuser 25.

Referring now to Figure 4, it will be noted that there is shown around shaft 26 the manner in which the parts are assembled. Starting from the bottom, there is an impeller 22, an up-thrust washer 24, a diffuser 25, a down-thrust washer 2 I, an impeller 22, an up-thrust washer 24, a diffuser 25, etc. 'I'his order of assembly is followed until as many stages as desired are assembled in the casing I5. The impellers 22 are constrained to rotate with the shaft through impeller key 21. The thrust of each impeller is imparted to the diffuser immediately below it by the down-thrust washer. Each diffuser is provided adjacent its upper portion with an internal shoulder 26 and adjacent its lower portion with an external shoulder 29. External shoulder 29 is adapted to seat on internal shoulder 23 so that there is a continuous column of nested diffusers formed, which column is housed by the casing I5. Formed integrally with each diffuser is a depending portion 30 of smaller diameter than the internal diameterof the diffuser. This depending portion is provided with passages 3l, adapted to conduct fluid inwardly toward the suction port 32 of an impeller. Each impeller is provided with aplurality of passages 33 through which the fluid is adapted to be thrown outwardly by centrifugal force into the diffuser space.

By referring to Figure 3, it will be obvious that liquid will be thrown out through the passages 33 of the impellers and will be conducted by the diffuser inwardly to the next impeller for continued travel through the pump, the liquid being thrown outwardly through the impeller passages 33 and flowing inwardly through the diffuser passages 3| to the port 32 of the next impeller. When a sufficient number of stages have been inserted in casing I5, a compression tube 34, provided with an external shoulder 35, Yadapted to seat upon the internal shoulder of the uppermost diffuser is set and the assembly located in place by an externally threaded, combined locking member and upper shaft bearing support 36. 'Ihe locking member is provided with a plurality of passages 31 through which the eduction fluid flows into the head I 6 and thence to the eduction tubing 3 and out of the well. A sleeve 33 is secured to the shaft above the uppermost impeller by means of set screws 39. A bearing bushing 49 is supported by the combined locking member and upper shaft bearing support 36. It

-will be seen that the thrust on each impeller is" transmitted to each diffuser so that the impeller thrusts are not transmitted to the shaft 26. The upper end of shaft 26, however, is exposed to the full pressure of the eduction fluid and this pressure, together with the weight of the shaft, is transmitted to a thrust bearing which is shown in Figure 5. The shaft 26 rotates at its lower end in a bearing packing 4I which may be of any suitable type. The shaft 26 terminates in a splined end 42 through which detachable connection is made with the thrust bearing through connecting member 43, which is provided with an integral thrust iiange 44. The thrust bearing proper comprises a housing 45, in which is positioned a plurality of anti-friction bearings shown in the drawings, as ball bearings, and provided with thrust races. The lower bearings comprise an inner race 46, formed with grooves 41 in which ball bearings 49 are adapted to travel. The outer races 49 are formed with lower seats 50 adapted to take downward thrust. A spacer ring 5I provided with passages 52 separates the upper bearing members from the lower bearing members. It will be noted that the outer race 53 of the uppermost bearing member is provided with a seat 54, adapted to take upward thrust. The outer race 55 of the lower of the upper two bearing members is similar in construction to the outer races 49 of the lower two anti-friction bearing members. It will be obvious that the downward thrust is transmitted from shaft 26 through thrust ange 44, through inner races to inner race rings of the three lower anti-friction members to their outer race rings and thence to annular shoulder 56, formed internally of the thrust bearing housing 45. The anti-friction members are held in assembled position in the thrust bearing by a snap ring 51. The thrust bearing housing is secured to the pump by means of stud bolts 58, the joint being made liquid-tight by a gasket 59. The member I1 is provided with a duct 60, through which before installation the air is vented under ingress of grease from the protector. As soon as grease reaches the duct 60, it is closed by a threaded plug 6I Referring now to Figure 2, it will be noted that the motor shaft 62 is coupled by coupling member 63 to an extension shaft 64 passing through the protector. The upper end of extension shaft 64 is coupled by coupling member 65 to the lower end of theshaft 66, which is in turn con-` rzisected by coupling member 43 to the pump shaft Referring now to Figure 3, it'will be obvious that fluid entering the pump through intake ports I3 will tend to seep under the pressure of submergence between the gland 4I and the shaft 26, seeping downwardly into the thrust bearing housing 45 and thence downwardly where, if the pump were directly connected to the motor, fluid would seep into the motor housing, causing damage which would eventually prevent continued operation. In order to obviate this seepage of fluid from the well, I interpose a protector between the motor and the pump. 'I'he arrangement of parts can be readily seen by reference to Figure 2. The protector proper comprises a casing 61. Within the casing 61 is a tube 13 through which the coupling shaft 64 passes. Within the casing 61 I position an annular piston 68 urged upwardly by a spring 69. The piston carries asealing member secured thereto by ring 1| and stud bolts 12. The casing 61 is provided with openings 1 I through which fluid within the well may readily iiow, exerting pressure upon the under side of piston 68. The space 1I within the housing 61 above the piston 68 is lled with a viscous lubricant such as a grease. A illiing duct communicating with the space 1I may be readily seen by reference to Figure 5. The duct is normally closed by a plug 16 and is provided with a check valve 11. Normally the spring 69 forces the piston upwardly until it makes contact with member 8D which closes the uppervportion of the housing 61. As grease is forced into the space 1l through the duct 15, the spring 69 is compressed. A spacer tube 8| is carried by the piston 68 and is adapted to contact member 82 which forms the bottom closure of the housing 61. The spacing tube 8| prevents the spring from being compressed beyond the desired extent.

It will be observed that in the construction provided, the hydrostatic.v pressure of the fluid within the well, acting on the under side of the piston through opening 1|', augmented by the thrust `of spring 69 forces grease upwardly, whence it will ow through duct 19 controlled by valve 18 past the thrust bearing members and upwardly between the spaces between stuffing box bearing 4| and shaft 26 oozing out eventually at the upper end of stuffing box bearing 4|. The exudation of the lubricant from between the space between the shaft 26 and the bearing Il will prevent the ingress of fluids from the well, thus not only effectively protecting the motor but lubricating the bearing 4| and the thrust bearing assembly. The upper end of extension shaft 64 rotates in bearing bushing 83 between which and shaft 64 a lubricant from the protector cannot flow, because the motor is filled with oil.

The ow of the grease or lubricant from the protector chamber is governed by valve 18, which is closed when the lled protector is in transit and opened before installing it in the well. 'Ihe protector is suiiiciently large to hold a volume of grease, enabling the assembly to continue operating for an extended period of time. In practice, a pump according to my invention has operated in adeep oil well in the Oklahoma City eld continuously day and night for over a year.

If there is sand and abrasive matter in the fluid being pumped, the impellers and diifusers may eventually become Worn. This is evidenced by a drop in the output pressure. At such times, it is necessary to pull the pump from the well land replace the worn elements. By means of my invention, this may be easily accomplished as will be obvious from the foregoing description. The grease supply in the protector is such that it willprotect and lubricate for an extended period of time, making frequent removal unnecessary.

It will be observed that I have accomplished the objects of my invention. I have provided a novel pump enabling a large number of stages to be conveniently and expeditiously achieved. Each of the diusers is the same as the others. All of the impellers are identical. The thrust bearing arrangement is such that it is constantly and properly lubricated. My arrangement is such that the thrust bearing need only receive the thrust upon the end of the shaft, inasmuch as the positioning ofthe impellers for axial movement upon the shaft enables them to transmit the individual thrust of the impellers to respec-v tive diifusers.

`It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in details within the scope of my claims without departing from the spirit of my invention. It is, therefore, to be understood that my invention is not to be limited to the specific details shown and described.

Having thus described my invention, whatI claim is: i

1. In a centrifugal pump, a casing, a plurality of diifusers housed within said casing in nested relation and retained between elements rigidly mounted on the well casing, adjacent diiusers forming impeller chambers, each of said diffusers being formed with a plurality of radially extending passages and with an axially positioned bore, a shaft extending through said axial bores, hnpellers positioned in said chambers and slidable on said shaft, means for rotating said shaft and means for preventing relative rotation between said impellers and said shaft while permitting axial motion with respect to said shaft, and means for transmitting thrust from each of said impellers to respective adjacent diiusers.

2. In a centrifugal pump, a housing having assembledl therein the following elements: an impeller, an up-thrust washer, a diffuser housing, a down-thrust washer, another impeller identical to said first impeller, an up-thrust washer identical to said first up-thru'st washer, a diffuser housing identical to said first diffuser housing, said diffuser housings being formed with means permitting them to be assembled in nested relationship whereby adjacent diffuser housings will form an impeller chamber, said thrust washers transmitting thrust from adjacent impellers to respective adjacent diffuser housings, means in each of said diffuser housings providing communication between an impeller chamber and the impeller positioned thereabove, a shaft extending centrally through said diffuser housings and said impellers, said impellersbeing positioned upon said shaft for axial movement therealong, means for rotating said shaft and means for preventing relative 'rotation between said impellers and said shaft.l

3. In a submergible, centrifugal pump assembly, an electric motor, a centrifugal pump, a 1ubricant reservoir positioned between said pump and said motor and forming a connection therebetween, a passage formed in said reservoir, a connecting shaft extending from said motor to said pump through said passage for driving said pump from said motor, said pump having a shaft, a thrust bearing for said shaft between said motor and said pump, a piston in said lubricant reservoir, a spring behind said piston, means providing communication between fluid in which said unit is submerged and the space behind said piston, a lubricant above said piston, and means providing communication between said lubricant reservoir and said thrust bearing whereby pressure exerted on said piston by said spring and said fluid in which the unit is submerged will cause lubricant to ilow to said thrust bearing.

4. In a submergible centrifugal pump assembly, a motor housing, a lubricant reservoir housreservoir housing being formed with an opening providing communication between fluid in which said assembly is submerged and the interior of said housing behindsaid piston; means providing communication between said lubricant reservoir above said piston and said thrust bearing.

5. In a submergible pump assembly, a centrifugal pump having impellers, a shaft for rotating said impellers, a prime mover for driving said shaft, a thrust bearing for said shaft, a lubricant reservoir secured to said pump, said thrust bearing being positioned between said reservoir i and said pump, a piston in said lubricant reservoir, lubricant; above said piston, means providing communication between said reservoir and said thrust bearing and means for urging said piston upwardly to force lubricant out of said reservoir through said passage to said bearing.

6. In a submergible pump assembly, a centrifugal pump having impellers, a shaft for rotating said impellers, a prime mover for driving said shaft, a bearing for said shaft, a lubricant reservoir secured to said pump, said bearing being positioned between said reservoir and said pump, a piston in said lubricant reservoir, lubricant above said piston, means providing communication between said reservoir and said bearing and means for urging said piston upwardly to force lubricant out of said reservoir through saidpassage to said bearing.

7. .In a submergible motor and pump assembly including a pump, an electric motor, a drive shaft connecting said motor to said pump for driving the latter, and an intermediate protector unit disposed around said shaft between said pump and motor, containing a sealing and lubricating fluid under pressure, said protector unit having means associated therewith for establishifm a pressure in said fluid which will cause said fluid to flow along said shaft away from said motor in the direction of said pump, the combination therewith of a bearing unit for disposition between said protector unit and said pump including a plurality of bearing elements ing, a thrust bearing housing and a centrifugal pump housing assembly in the order named, said forming a thrust bearing for supporting said shaft, said bearing unit having passages therein through which -said fluid flows, said bearing eleint being disposed in the path of said fluid 8. In'a submergible motor and-pump assembly including a pump and an electric motor, a

driveshaft connecting said motor to said pump for driving the latter, and an intermediate protector unit disposed around said shaft between said pump and motor, containing a sealing and lubricating fluid under pressure, said protector unit having means associated therewith for establishing a pressure in said fluid which will cause said fluid to flow along said shaft away` bly, the combination comprising a motor, a pro-` tector unit .having a sealing fluid reservoir mounted on said motor, a thrust bearing unit mounted on said protector unit, a packing chamber unit mounted on said bearing unit, a pump mounted on said packingchamber unit, a drive shaft extending from said motor through said unit into operating connection with said pump, said bearing unit being provided with passageways for conducting said sealing fluid from said protector unit to said packing chamber, and means for effecting a ilow of fluid from said reservoir to said packing chamber through said bearing unit.

10. In a centrifugal pump, a casing, a plurality of diifusers housed within said casing in nested relation, adjacent diusers forming impeller chambers. each of said diifusers being formed with a plurality of radially extending passages and with an axially aligned bore, a shaft extending through said axial bores, impellers positioned in said chambers and axially slidable on said shaft, respective thrust rings aboveeach impeller, respective thrust rings below each impeller, said thrust rings being adapted to transmit thrust from respective adjacent impellers to respective adjacent diffusers, means for rotating said shaft and means for preventing relative rotation between said impellers and said shaft. g l ARMAIS ARUTUNOFF.

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