US 2283195 A
Description (OCR text may contain errors)
May 19, 1942. A. FARRELL ETAL 2,233,195
ADJUSTABLE MOTOR-PUMP Filed mar h '22, 195 j '2 She'ets-Sheat 1 May 19, 1942. A. FARRELL :TAL v ,283,195
ADJUSTABLE MOTOR-PUMP Filed March 22, 193B 2 Sheets-Sheet 2 Patented May 19, 1942 STATES PAE ADJUSTABLE oron p Application March 22, 1938, Serial No. 197,394
This invention relates generally to submersible motor-pump units, and is directed particularly to a motor-pump unit having means operable from the surface of the well for adjusting the pumping elements.
Submersible motor-pump units comprise generally a submersible electric motor and a pump, both suspended from the lower end of a discharge column extending from the well surface to adjacent or below the level of the well liquid. The pump is usually a multi-stage centrifugal pump of the bowl type having impellers mounted on a pump shaft projecting downwardly through the suction inlet at the lower end of the pump. The motor casing is usually suspended from the pump casing, with a motor adapter and strainer interposed between the two casings. The motor shaft and pump shaft are direct connected, the downward hydraulic thrust of the pump being transmitted to the upper end of the motor shaft and absorbed by a thrust bearing in the motor housmg.
When a deepwell pump of the open or semienclosed impeller type is first installed in a new well, it is customary to provide considerable clearance between the impellers and the lower walls of the impeller chambers, because of the relatively large amount of sand in the well liquid. As the well becomes cleaned out, it is desirable to decrease this clearance in order to increase the pump eficiency. In deepwell turbines wherein the motor is located at the surface of the well and is connected to the pump by a drive shaft extending downwardly from the surface, the impeller clearance can be changed by axial adjustment of the pump shaft.
However, in a submersible motor-pump unit no shaft extends to the surface and consequently, if an adjustment of the impellers is to be eff ected without pulling the pump out of the well, some other provision must be made.
A principal object of this invention is to provide a submersible motor-pump unit including means operable from the surface of the well for adjusting the pumping element relative to its casing while the unit remains in the well.
A further object is to provide a submersible motor-pump unit including means operable from the well surface for adjusting the pumping element, without requiring additional equipment extending from the unit to the surface.
A still further object is to provide means for adjusting the pumping element through a wide range of adjustment, by a series of very small increments.
A still further object is to provide adjusting means operable by energization of the motor in reverse direction.
Yet a further object is to provide an adjustable coupling between the motor shaft and the pump shaft, capable of varying the effective length of said shafts.
A further object is to provide a ratchet adjusting means between the motor shaft and the pump shaft, operable to effect a wide range of adjustment through successive increments, each increment of adjustment being obtained by energization of the motor in a direction reverse to the normal direction of rotation.
A still further object is to provide a ratchet adjusting means between the motor shaft and pump shaft, which is positive in action and incapable of effecting inadvertent adjustment as the result of involuntary torque reversals.
Other objects and advantages will be apparent from the following description, taken in conjunction with the accompanying drawings, wherein:
Fig. l is an elevation of a motor-pump unit installed in a well, with parts broken away to show one of the pumping elements and the adjusting means;
Fig. 2 is a view of the adjusting means, partly in elevation and partly in longitudinal section;
Fig. 3 is a view similar to that shown in Fig. 2, but taken at a right angle to the latter; V
Fig. 4 is a fragmentary view of a portion 0; the device of Figs. 2 and 3, showing a portion not visible in those figures; and s Fig. 5 is a transverse section on line 5--5 of Fig. 2.
Referring to Fig. 1 cf the drawings, a submersible motor-pump unit is shown comprising a pump casingv I having a pump shaft 2 rotatable therein, a strainer 3 bolted to the lower end of the pump casing, a motor adapter 4 secured to the lower end of the strainer, and a housing 5 of a submersible electric motor secured to the lower end of the motor adapter. An impeller 6 of the open runner'type is mounted on the shaft 2. While for-purpose of illustration only one pump bowl is shown, it will be understood that ordinarily a plurality of such bowls are connected in series. The pump shaft 2 extends downwardly through the strainer and terminates within the adapter 4, where it is connected in driving relation with the upper end of the mo-,
tor shaft 1 by an adjustable coupling means generally designated ID.
The unit is suspended from the surface of the well by a discharge column (not shown) to the ,lower end of which the pump casing is secured. The motor receives current through a conductor cable l2 extending from the motor to a control panel at the surface.
The weight of the pump shaft and impellers, and the downwardly acting hydraulic thrust exerted during operation, are transmitted from the pump shaft 2 to the motor shaft I, and are transferred to the motor housing by a thrust bearing (not shown) on the motor shaft within the motor housing. In the present instance the clearance between the impeller 6 and the casing is varied by varying the effective length of the shafting' between the thrust bearing and the impeller. The means by which this is accomlished will now be described. I
Referring to Figs. 2 and 3, the adjacent ends of the shafts 2 and I are connected in driving r'elation by' a pair of complementary coupling members l5 and I6 keyed at H and I8 respectively to the shafts. The upper, driven coupling member I5 is provided with a pair of depending segmental jaws l9 and 26 projecting within recesses formed between complementary upstanding jaws 2| and 22 on the lower driving coupling member I6. The normal direction of rotation of the motor is counterclockwise as viewed from above, and is indicated by the arrows 25, Figs. 2, 3, and 5. During normal rotation the advancing radial faces 26 and 21 on the driving coupling jaws 2| and 22 engage opposed radial faces 28 and 29, respectively, on the driven coupling jaws i9 and 20.
As shown in Figs. 4 and.5, each of the jaws is slightly less than 90 in angular extent, whereby the receding faces 3| and 32 on jaws 2| and 22 are spaced arcuately from faces 33 and 34 on jaws l9 and 20 during normal rotation. Consequently on reversal of the direction of rotation of the motor there will be a slight lost motion prior to engagement of faces 3| and 32 with faces 33 and 34 respectively. The reason for the provision of this lost motion will be explained presently.
The lower end of the pump shaft 2 is provided with an integral, reduced stud 4| having left-hand threads cut thereon. Threaded to the stud is a ratchet nut 42 having ratchet teeth 43 on its outer periphery, the teeth being inclined in the direction of 'normal rotation of the motor, as shown in Fig. 5. The nut normally extends below the lower end of the stud 4|, and engages the upper end of the motor shaft 1. It will be obvious that by adjusting the nut axially of the stud the pump shaft 2 may be raised or lowered. The ends of the coupling jaws are axially spaced from the bases of the complementary recesses into which they extend, so as to insure that the axial thrust will be transmitted through the nut irrespective of the adjusted position of the latter on the stud 4|.
The purpose of the lost motion between the jaws is to eflfect a partial rotation of the nut 42 on the stud 4| each time the motor is energized in reverse direction. To accomplish this result, a pawl 45 having a tooth 46 engageable with the teeth on the nut 42 is resiliently mounted for sliding movement in a radially extending bore in the jaw 2|. The pawl is yieldably urged inwardly by a leaf spring 48 secured by a set screw. 46 in a recess 50 in the jaw, whereby on reversal of the direction of rotation of the motor the tooth 46 on the pawl engages a tooth on the nut 42 and turns thelatter relative to the stud 4| while taking up the lost motion between the coupling jaws. The direction of rotation of the nut on the stud is clockwise as viewed from above, and since the threads on the nut and stud are lefthand, the nut is moved upwardly on the stud. When the direction of rotation of the motor is again reversed back to normal, the spring 48 yields to permit the tooth 46 to ride over the adjacent tooth on the nut and drop into the recess behind the next tooth, preparatory to the next adjustment.
Reference to Fig. 2 discloses the manner in which the spring is adequately supported against misalignment. The lower end thereof is rigidly secured by the set screw 49, and the upper end is reduced at 5| to enter a slot 52 in-the head of the pawl 45. The spring is thus securely retained in operative engagement with the pawl.
The spring '48 should be sufiiciently strong to insure that the pawl tooth 46 engages a tooth on the nut. There is the possibility, therefore, that during retrograde movement of the pawl the nut will return with the pawl, provided the spring 48 unduly resists outward movement of the pawl. However, in order to positively insure against such an occurrence, a holding pawl 55 is slidably mounted in a bore in'the driven coupling jaw l8 and is provided with a tooth 56 similar to tooth 46. The pawl 55 is resiliently urged inwardly by a leaf spring 58, and in this case a second leaf 58 is provided to offer suflicient resistance to turning of the nut to prevent inadvertent adjustment thereof.
During the adjustment of the nut by the pawl tooth 46 as described above, the holding pawl tooth 56 rides over the adjacent tooth on the nut and drops into the recess adjacent said tooth. Reversal of the motor to normal directionv of rotation merely results in the driving faces 26 and 21 re-engaging the driven faces 28 and 29, the nut being held in its new adjusted position by the holding pawl.
As an added precaution against inadvertent adjustment of the nut, a spring 6| may be interposed between the faces 3| and 33 on the jaws 2| and I8. This spring shouldbe of sufficient strength to maintain the faces 3| and 83 separated except when the motor is energized in reverse direction. In the latter event the spring will be forced into the recess 62 countersunk in the face 3|, permitting the faces 3| and 33 to engage and the nut to be turned by the pawl tooth 46 the full width of one of the teeth on the nut.
To prevent entrance of sand or other solids into the pawl mechanism, and to provide a lubriouter ends with inwardly facing shoulders II and I2, respectively, which limit the inward movementof. the pawls. The lower face of the nut 42 is beveled as shown 'at 13. This construction ermits the separate assembly of the coupling members with their respective shafts and the subsequent coupling of the shafts simply by relative axial movement thereof into abutting relation. During this movement the sleeve 65 passes over the coupling member l6 and the driving .jaws slide into engagement. The pawls 5 and 55 are engaged by the beveled shoulder 11 on the nut 42 and shifted outwardly a slight amount until the teeth 48 and 56 engage the toothed periphery of the nut. The pump shaft and coupling member I6 are then free to move downwardly until the lower face of the nut 42 rests on the end of the motor shaft 1.
'Thehere'in described adjusting device is particularly adapted to the adjustment of the im-- peller clearance of a deepwell centrifugal pump of the open or semi-enclosed impeller type. As
stated above, a relatively large clearance is required when the pump is first installed in anew well, because of the amount of sand in the well fluid. Subsequently the clearance should be reduced to a minimum. The present device protion of the usual coupling, rather than an added piece of equipment..
The adjustment effected by each reversal of the motor is positive andof a predetermined magnitude, and the possibility of inadvertent adjustment as the result of involuntary reversals of the torque is effectively precluded. As a consequence, the position of the nut on the stud is always known if a record of the adjustments is kept. The correct operating position can also be determined by observing the power input to the motor.
While we have shown what'is considered av preferred embodiment of the invention, it is to be understood that various changes maybe made within the spirit of the invention and the scope of the appended claims. a
1. In a rotary pump unit, a pump adapted to be supported in'a well and comprising a rotor and 'a stator, a rotor shaft, a drive shaft, means interconnecting said shafts in torque-transmitting relation whereby the rotor shaft is rotated by the drive shaft, said connecting means being vides a wide range of adjustment, of the order the stud M. The latter then rests directly on the motor shaft and further actuation of the adjusting mechanism results merely in screwing the nut farther up on the stud.
To reduce the impeller clearance, the motor leads are reversed and the motor circuit momentarily closed, energizing the motor in reverse direction and turning the nut -62 on the stud Al the width of one tooth. Reversal of the leads to normal position and closing the circuitcauses The latter is made of greater axial the coupling jaws to re-assume their normal driving relation. By repeating the foregoing steps the impeller clearance mayrbe reduced any desired amount. Inasmuch as the initial clearance is usually known and the amount of each adjustment is a predetermined, known amount, the number of adjustments required to obtain a desired clearance is easily ascertained. Also, by observing the power input to the motor while making the adjustment, the proper clearance can be ascertained.
A very desirablefeature of the adjusting device described is the absence of'auxiliary'equipment extending from the surface to the motor-pump unit, the adjusting force being transmitted from the surface through the motor conductor cable. The device is exceedingly simple, consisting of only a very few parts, resulting in economy of manufacture and adding little to the cost of the motor-pump unit. As shown in Fig. 1, the device is embodied in the shaft coupling usually provided between the pump and motor shafts, and consequently involves merely a slight modificalocated within the well and comprising a coupling member secured to each shaft, interengaging jaws on said coupling members, and a lostmotion connection between said jaws, and means associated with said connecting means for adjusting said rotor relative to said stator, comprising means operable during relative rotation of said jaws in one direction for adjusting said rotor shaft axially relative to said drive shaft.
2. A motor-pump unit comprising a pump and a motor adapted to be supported in a well, the
pump comprising a casing, a pump shaft rotatable therein, and a pumping element secured to the shaft; a motor shaft aligned with said pump shaft, means connecting said shafts in operative relation comprising a coupling member secured to each shaft, interengaging jaws on said coupling members, and a lost-motion connection between said jaws; means for adjusting one of said shafts axially relative to the other shaft during relative rotation between said jaws through said lost-motion connection, said adjusting means comprising a ratchet wheel threadedly connected to one of said shafts, a pawl mounted on the coupling member secured to the other shaft and operatively engaging said ratchet wheel, and a holding pawl on the other coupling member en'- gaging said ratchet wheel to prevent turning therleof during retrograde movement of said first paw 3. In a rotary pump unit, a pump adapted to be supported in a well and comprising a rotor and a stator, a rotor shaft, a drive shaft, means interconnecting said shafts in torque-transmitting relation, whereby the rotor shaft is rotated by the drive shaft, said means being located within the well, and means associated with said connecting mean and responsive to reverse rotation of said drive shaft for; adjusting said rotor relative to said stator, while said pump remains supported in the well, said torquetransmitting interconnecting means including a lost motion connection and said adjusting means being operable by rotation of said drive shaft relative to said rotor shaft through the extent of said lost motion only.
4. In a rotary pump unit, a pump adapted to be supported in a well and comprising a rotor and a stator. a rotor shaft, a drive shaft, means interconnecting said shafts in torque-transmit.- ting relation, whereby the rotor shaft is rotated by the drive shaft, said means being located within the well, and means: associated with said connecting means and responsive to reverse rotation of said drive-shaft for adjusting said rotor relative to said stator while said pump remains supported in the well, said adjusting means including an adjusting member threadedly connected to one of said shafts and having abutting engagement wtih the other shaft, means for rotating said adjusting member relative to said threadedly-connected shaft, and means for holding said adjusting member in any adjusted position.
5. In a rotary pump unit, a pump adapted to be supported in a well and comprising a rotor and a stator, a rotor shaft, a drive shaft, means interconnecting said shafts in torque-transmitting relation, whereby the rotor shaft is rotated by the drive, shaft, said means being located within the well, and means associated with said connecting means and responsive to reverse rotation of said drive shaft for adjusting said rotor relative to said stator while said pump remains supported in the well, said torque-transmitting interconnecting means including a lost motion connection and said adjusting means comprising a ratchet wheel threadedly connected to one of said shafts, and a pawl secured to the other shaft cooperating with said ratchet wheel.
6. A rotary pump unit comprising a stationary element, a rotary pumping element,drive means connected to said pumping element for imparting rotation thereto in a pumping direction, and means including said drive means for adjusting said pumping element axially with respect to said stationary element, said adjusting means being operable solely in response to reverse rotation of said drive means, and said adjusting means including means for maintaining said pumping element in adjusted position throughout subsequent periods of rotation in pumping direction and during subsequent periods of rest. 4
7. A-rotary pump unit comprising a station-,
ary element, a'rotary pumping element mounted therein for rotation and axial adjustment relative thereto between predetermined limiting positions, drive means connected to said pumping element for imparting rotation thereto in a pumping direction, and means including said drive means for adjusting said pumping element axially with respect to said stationary element into successive intermediate positions between said limiting positions, each of said adjustments being efl'ected upon rotation of said drive means in reverse direction and subsequent rotation in pumping direction, and said adjusting means including means for maintaining said pumping element in any adjusted position during subsequent rotation in pumping direction and during subsequent period of rest.
8. In a rotary pump unit, a stator, a rotor mounted therein for rotation. and axial adjustment relative thereto, a rotor shaft, a drive shaft for rotating and axially supporting said i'otoi ble in responseto predetermined motion of said drive shaft for adjusting said thrust-transmitting means relative to said one shaft, to thereby adjust the axial position of said rotor with respect to said stator.
9. A rotary pump unit comprising a stator, a rotor normally rotatable in one direction, sectional drive means connected to said rotor for rotating and axially supporting said rotor, means for rotatably and axially supporting said drive means at a point spaced from said rotor, means interconnecting the sections of said sectional drive meansin positive driving relation with each other, said interconnecting means including means operable solely in response to reverse rotation of said drive means to axially adjust the sections of said sectional drive means with respect to each other and thereby vary the effective length of the latter between said supporting means and said rotor, said adjusting means including mean for maintaining said sections in axially adjusted relation during subsequent rotation in normal direction and during subsequent periods of rest. 4
10. A rotary pump unit comprising a stator, a rotor mounted therein for rotation and for axial adjustment with respect thereto between limiting positions, sectional drive means connected to said rotor for rotating and axially supporting said rotor, means for rotatably and axially supporting said drive means at a point spaced from said rotor, and means interconnecting the sections of said sectional drive means in positive driving relation with each other, said interconnecting means including means operable in response to rotation of said drive means in a predetermined direction to axially adjust the sections of said sectional drive means with respect to each other and thereby axially adjust said rotor with respect to said stator, said adjustment being in increments of predetermined magnitude less than the axial distance between said limiting positions of said rotor,-irrespective of the duration and speed of rotation of said drive means in said predetermined direction.
' ASA FARRELL.
ALADAR HOLLANDER. VAINO'AQ HOOVER.