US2210977A - Strainer for submersible motor pumps - Google Patents

Description

' Aug. 13, 1940.

A. HOLLANDER Filed Dec. 8, 1937 STRAINER FOR SUBMERSIBLE MOTOR PUMPS INVENTOR.

, Patented Aug. 13, 194i) UNITED STATES- g 10,911 s'r'asnma non sununnsmm moron rusnrs A Aladar Hollander. Angele's, 'Calif., assignor to. Byron Jackson 00., Huntington Park, Calif, a

Corporation of Delaware Application December a, 1937, Serial No. 178,738

' 3 Claims. (01. ins-111) This inventi n relates to motor pump units adapted to be suspended within a well and im- ,mersed ln'the liquid to be pumped. i r

3 1 More'particularly, the invention is directed to improvements in; a motor. pump unit in-which the motor is suspended below the pump in axial alignment therewith, and the pump intake is located intermediatethepumpand the motor.

In-a unit of the aforementioned type a strainer is usually provided for the" purpose of limiting the maximum size of solid particlesentering the pump. Inasmuch as the strainer section is interposed between the pump and -the motor, it serves to support the weight of the motor and 18 also to transmit the reaction torque of the motor to-the pump casing. Furthermore, thestrain'er is of an appreciable length, in order to provide a flow capacity commensurate with the pump capacity, thus giving rise to the necessity of pro- 20 viding a bearing support for the pump shaft at l a point intermediate the pump and the motor.

In prior devices of the aforementioned type embodyinga strainer, the well liquid is deflected radially inwardly as it enters the strainer from thewell casing,- and is then agalndeiiected'inan upward direction. This change in direction seriously impedes the .flow of the liquid, and causes turbulence therein at the point of entry of the liquid into the throat of the pump. By the pro- .30 vision-of the novel strainenhereinafterdescribed,

in conjunction with a suctionspiece of novel construction interposed between the strainer and the pump, this difliculty is overcome and there is provided substantially straight-line new. from the well casing to the pump. p

The suction piece referred to in the preceding jparagraph functions additionally as an adapter,

nbetween the pump and the strainer, the basic design of the suction piece being such a's'to o render it susceptible ,of construction in a wide variety of relative upper andflower diameters.

Irrespective of the particular relative. diameters.

however. it cooperates with thefstrainer to eifectsubstantially straight-line flow of-iiqnidfrom the well casingtothepump. I

A principal object of thisinvention is taprovide a strainer of novel and improved construetio'n, having incorporated thereina shaft support as an integral part thereof.

A iurther object of the invention lies in the provision of a strainer .which provides substantially 'straight-line flolw of fluidfrom the well resistance'to flow of fluid theretlirough.

.pump. which is substantially free from directionpacity and h'ead. as well as we'll diameter limitaindependently of the motor shaft. Furthermore. g

of the upper end of the motor casing is required 'vide a novel motor pump-assembly wherein an provision of a strainer which is constructedto withstand torsional as well as tensile strains imposed thereon by the motor, while retaining fea-' Another object of the invention lies in thecoms bination of a novel strainer with a novel suction piece, the eombined eflect of which is to provide changing surfaces. .10

Individual well requirements as to flow cations, call for the selection from a wide' range of pump sizes and of motor sizes for most eflicient operation. It is a further object of this inven- 18 tion to. provide a novel motor pump assembly which permits oi the use of a wide range of pump sizes with 'an equally wide range or motor sizes, without the necessity of supplying a different size :if strainer for .each motor pump size combinaon. v For obvious reasons, the weight of the motor casing in a motor pump unit of the type referred to herein is carried by the superposed sections,

access to' the interior of the unit in the're'gion duringassembly of the unit after the sections have been. connected together and the umt is suspended from above. Yet another object of .a the invention resides in the novel arrangement aflording free and unobstructed access to the interior of the unit between the motor and the pump while the unit is suspendeddrom. above.

A still further object'of the invention is to pro- 3 adspteris'interposed'between the motor and the strainer for the purpose of adapting motors oi varying easing diameters to a single strainer,

the-adapter supporting the motor and-being dl- 1" vided'longitudinaily into two or more sectionsg whe eby one section ma be removed to provide unobstructed access to. the interior thereof while P an&hersectionfsupports the motor. I

, er obieets and advantages will be apparent n tothose'skilled-lntheart andwillbemadeeviconjunction with the accompanying drawing,

" liiguiei'i is aview. partlyin side elevation and "I I j partly-in vertical section, of a motor pumpassembly embodying the invention: casing to the pump, thus oil'ering" aminim'um of Figure 2 is a vertical sectional viewpf. the" strainer, taken on line 2-4 of Flgr33 Figure}. is a'horlzontalsection throughthe strainer taken on line 3-4 of Figure 2; and

Figure 4 is a horizontal section through the light adapter, taken substantially on line l-l of Referring to Fig. 1 of the drawing, a pump l, herein shown as a centrifugal pump, is adapted to be attached to the lower extremity of a string of pipe (not shown) and lowered into a well and immersed in the liquid to be pumped.

Bolted or otherwise secured to the lower end of the pump is a suctionpiece 2, comprising an upwardly and inwardly converging neck portion 3 defining a throat l communicating with the impeller chamber of the pump.

The lower, or intake, end of the suction piece 2 is connected, by cap screws 5 or other suitable means, to the upper end of a strainer, designated generally by reference numeral 8.

Supported from the lowerend of strainer 6 is an adapter I, interposed between strainer 6 and an electric motor 8 deriving current from the sur-, face through an electric cable, (not shown). It will thus be seen that each elementof the assembly is subjected to the weight of those elements suspended below it, and also that the reaction torque of the motor is transmitted successively through each element to the pump above.

Referring now to the novel strainer 6, in its preferred embodiment it is formed as an integral structure, as by casting. An upper, annular flange member 9 and a lower annular flange member I0, of lesser diameter than the upper member, are connected by'a plurality of radially extending ribs ll (Figs. 2 and 3), herein shown as four in number. These ribs are formed as radial projections on a centrally disposed hub member l2 extending substantially the entire length of the strainer.

As will be seen from Figs. g and 3, the upper end of the strainer is open, the annular space between the upper flange member 9 and the hub l2 being bridged only at spaced intervals by the ribs 1 l, to provide passage for the flow of liquid to the suction piece. However, the lower end is closed by the flaring base portion l3 formed at the lower end of the hub l2 and uniting the latter with the lower flange member III.

Inasmuch as the strainer is subjected to the reaction torque of the motor, it is essential that the torque-transmitting portions thereof be of suflicient strength. In prior devices wherein the strainer portion is utilized to transmit torque, it has been found necessary to provide an excessively large strainer in order to furnish the requisite strength and also provide sufficient openings for the flow of liquid to the pump. By the provision, however, of a torque-transmitting member entirely distinct and separate from the strainer elements, whereby the-latter need not be relied on for this purpose, the strainer elements may be of appreciably lighter construction, affording a much higher ratio of flow area to strainer surface. As a result, the size of the strainer may be reduced appreciably while retaining the requisite flow capacity and torsional strength.

According tothe invention, the strainer elements comprise spaced bars ll extending longitudinally of the strainer between the peripheral portions of the upper and lower flanges-8 and II. The slots it formed stit-ute channels for' the passage of fluid from the well to the pump, while excluding solid particles exceeding a predetermined size. As shown in Fig. 3, the bars i4 taper radially inwardly, in order that the width of the slots It shall be at between adjacent bars con-'- least equal, throughout their depth, to the width at the outer periphery. In this way the possibility of solid particles becoming wedged in the slots is precluded. As shown in Fig. 1, the bars ll also taper downwardly in order to provide slots of uniform width from top to bottom; it has been found that by this arrangement more uniform flow conditions are obtained, as will be explained more in detail hereinafter.

Formed within the hub member l2 are spaced bearing supports IS, IS for the reception of sleeve bearings 11, ll (Fig. 1) in which is journaled the pump shaft l8 extending from the motor to the pump and coupled at i8a to the motor shaft By the provision of a bearing support integral with the strainer, adequate lateral support of the pump shaft is assured at this point. As shown in Fig. 1, the pump shaft terminates a short distance below the strainer, and the advantages of providing a bearing within the strainer will be readily apparent.

An important feature of this invention is the downwardly tapered construction of the strainer, in conjunction with the full length strainer slots and the suction piece. Motor pump units of this type are usually installed in a well at some point above the well screen forming a part of the well casing 19. The clearance between the motor casing and the well casing provides an annular space for the passage of liquid from theperforations of the weli screen upwardly around the motor casing and into the strainer. By the present invention, this upward course of the liquid is continued until it reaches the-pump impeller, with only a gradual deflection radially inwardly, in contrast to the relatively abrupt deflection inwardly and then upwardly which characterizes the usual cylindrical strainer with short, staggered openings. It will be obvious to those skilled in this art that improved operation of the pump will be effected by the elimination of turbulence at the pump intake as the result of this in-.- vention.

The adapter 1, interposed between the strainer and the motor casing, comprises a frustro-conical, housing 2| provided with upper and lower bolting flanges 22 and 23. In the preferred form, the housing and flanges are split longitudinally at 24 on a diametral plane (Fig. 4) forming two mating sections 25 and 25,, and for the purpose of securing the two sections in assembled relation each section has formed thereon, at opposite sides thereof, a pair of radial flanges 21 extending between upper and lower flanges 22 and 23 and bolted together as at 28. In order to render the adapter capable of withstanding torsional strains imparted thereto by ribs 28 and 30 are provided.

As clearly shown in Fig. l, the end faces of the flanges 22 and 23 and the corresponding abutting faces on the lower endof the strainer and the upper end of the motor housing are provided with complementary centering shoulders machined to provide a true centering fltbetween these parts, assuring proper alignment of the shafts I3 and l8 and of the mating halves of Thus it is only necessary to secure one of the sections 25 or 26 of the adapter between the strainer and the motor housing in order to establish and maintain proper alignment of these elements and consequently of the shafts, the interior of the adapter being fullyvexposed and accessible for assembly of the coupling and inspection of the alignment of the shafts.

For various reasons, it is necessary to provide the coupling ll.

the motor, strengthening access to the interior of the adapter without disturbing the assembled relation of the motor,

in rigid assembly. It will be understood'that I after the unit is assembled and the motor casing is filled with a dielectric fiuid, as is customary, it

must be suspended in vertical position while performing various final assembly operations, such as axial adjustment of the pump, etc. It is in this connection that the split adapter aifords a convenient means for obtaining access to the interior while still supporting the motor therefrom, and'maintain ing axial alignment of the shafts.

Referring to the assembly as a whole, it will be observed that an adapter is provided both between the strainer and the pump and between the strainer and the motor. For the great variations of flow capacity, pumping head, and well diameter, it will be appreciated that a large number of pump sizes and of motor sizes are required, and the number of combinations of pump sizes and motor sizes is correspondingly greater. If

the pump and motor were connected directly to, opposite ends of the strainer, it is obvious that,

not only would a strainer of a diiferent size be required for each combination of motor and pump, but it would be impossible to provide in all cases a strainer of inverted frustro-conical shape having the improved hydraulic properties wdiscussed previously. By the provision of an adapter at each end of the strainer, it is' possible to provide a relatively small number of strainer sizes, each of which is of the proper relative upper and lower diameters to provide the desired taper. Furthermore, it will be observed that both the lowersplit adapter and the upper combined suction piece and adapter are of simple construction and capable of being manufactured at low cost, and consequently the capital investment involved in maintaining a stock of a wide variety of sizes of such adapters would be much less than would be the case if individual strainers were provided for each combination of pump and motor. o

From the foregoing it is believed that the novel of substantially constant width throughout their features of my invention may be'readily understood by those skilled in the art. It is to be understood that the particular embodiment shown and described is for illustrative purposes only, and that various changes and modifications 5 may be made without departing from the spirit of the invention. I I claim:

1. A strainer adapted to be connected between the pump and motor of a submersible motor 10 pump unit, said strainer comprising upper and lower end portions connectible respectively to said pump and to said motor, said upper end por tion being substantially of the same diameter as the suction inlet of said pump and adaptedto be in open communication therewith. said lower end portion being of lesser diameter than said upper end portion and being closed, and strainer bars extending-in spaced relation between said end portions and defining therebetween aninverted frus'toconical cage, the circumferential width of the strainer bars being decreased from top to bottom, whereby the spaces between the barsare ]Ength. I I

2. A combined strainer and bearing support adapted to be connected in supporting and torque-transmitting relation between the pump and motor of a submersible motor pump unit, comprising upper and lower end portions connectible respectively to said pump and.to said motor, said upper end portion being substantially of the same diameter as the suction inlet of said pump and adapted to be disposed in open communication therewith, said lower end portion being of lesser diameter than said upper end portion and being closed, a plurality of substantially radially extending ribs connecting said end portions'in supporting and torque-transmitting relation, a centrally disposed hub connecting the inner edges of said ribs, pump-shaft bearing means in said hub, and

' longitudinal" strainer bars extending in spaced relation between said end portions and defining therewith an inverted frusto-conical cage, the circumferential width of the strainer bars being decreased from top to bottom to provide strainer slots of substantially constant width throughout their length.

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