Downhole pump top plunger adapter with improved sand handling capability

Abstract

An adapter for coupling between a rod and a plunger in a downhole pump has a shaft with an axial through bore, and a cup spanning around a neck portion of the shaft to create an open-topped sand trap annulus between the shaft and cup. Sand trap ports in the shaft wall fluidly communicate the axial through bore and sand trap annulus. A sand trap shoulder on the shaft above the sand trap annulus is flushed clean during the pump downstroke by angled cleanout ports in the shaft wall. The sand trap shoulder is of lesser outer diameter than the cup, whereby the sand trap shoulder denotes a partial sand trap that captures a first fractional portion of sand found in fluid above it, while permitting a second fractional portion of sand to pass downwardly by the sand trap shoulder for capture by the sand trap annulus.

Claims

1. An adapter for coupling between a rod and a plunger in a downhole pump system, said adapter comprising: a shaft having an axial through-bore passing axially therethrough from a top end of the shaft to an opposing bottom end thereof, and being configured at an upper coupling portion for coupled attachment to a first component of the downhole pump system of uphole relation to the adapter; a cup having a chambered upper portion spanning circumferentially around the shaft at a neck portion thereof that resides below said upper coupling portion and inside a hollow upper chamber of the chambered upper portion of the cup, said hollow upper chamber being open at a top end of the cup and having an internal diameter that exceeds an external diameter of the neck portion of the shaft, thereby leaving an open sand trap annulus between the shaft and the cup at the chambered upper portion thereof; one or more sand trap ports penetrating a peripheral wall of the shaft at the neck portion thereof and thereby fluidly communicating the axial through-bore of the shaft with the open sand trap annulus between the shaft and the cup at chambered upper portion thereof; a sand trap shoulder provided on the shaft at a location thereon above both the neck portion of the shaft and the upper chambered portion of the cup, said sand trap shoulder spanning circumferentially around the shaft and imparting a localized increase of external diameter to the shaft relative to neighbouring areas thereof immediately above and below the sand trap shoulder to hinder passage of sand, situated outside the shaft, from above the sand strap shoulder downwardly therepast toward the plunger; and angled cleanout ports penetrating an exterior of the peripheral wall of the shaft just above the sand trap shoulder and penetrating an interior of the peripheral wall, into the axial through bore of the shaft, at lesser elevation thereon than where the angled cleanout ports penetrate the exterior of the exterior of the peripheral wall, said angled cleanout ports being operable to flush clean the sand trap shoulder during a downstroke of the downhole pump system; wherein an outer diameter of the sand trap shoulder of the shaft is less than an outer diameter of the cup so that the sand trap shoulder denotes a partial sand trap effective to capture a first fractional portion of said sand, while permitting a second fractional portion of said sand to pass downwardly past the sand trap shoulder to the cup, where the second fractional portion of said sand capturable by the sand trap annulus at the chambered upper portion of the cup, whereby the sand trap and the cup cooperatively inhibit downward passage of sand to the plunger.

2. The adapter of claim 1 wherein the angled cleanout ports are each smaller in size than each of the one or more sand trap ports.

3. The adapter of claim 1 wherein the angled cleanout ports are provided in greater quantity than the one or more sand trap ports.

4. The adapter of claim 1 wherein the angled cleanout ports are distributed, in a circumferential direction around the shaft, in a more densely spaced distribution than the one or more sand trap ports.

5. The adapter of claim 1 wherein the exterior of the shaft comprises a flared transition beneath the sand trap shoulder that gradually widens theretoward.

6. The adapter of claim 5 wherein said flared transition is concavely contoured.

7. The adapter of claim 1 wherein the shaft comprises additional angled cleanout ports in the neck portion thereof that penetrate the exterior of the peripheral wall inside the hollow upper chamber of the cup, and penetrate the interior of the peripheral wall at an elevation lower than where said additional cleanout ports penetrate the exterior of said peripheral wall.

8. The adapter of claim 7 wherein the additional angled cleanout ports reside below the one or more sand trap ports.

9. The adapter of claim 7 wherein the angled cleanout ports are each smaller in size than each of the one or more sand trap ports.

10. The adapter of claim 7 wherein the additional angled cleanout ports are provided in greater quantity than the one or more sand trap ports.

11. The adapter of claim 7 wherein the additional angled cleanout ports are distributed, in a circumferential direction around the shaft, in a more densely spaced distribution than the one or more sand trap ports.

12. The adapter of claim 7 wherein the additional angled cleanout ports penetrate the exterior of the peripheral wall at, or upwardly adjacent of, a topside of an external abutment shoulder of the shaft that resides at a bottom of the sand trap annulus and abuts against an internal stop shoulder of the cup that is located at a bottom of the hollow upper chamber thereof.

13. The adapter of claim 12 wherein the additional angled cleanout ports penetrate the exterior of the peripheral wall at the topside of the external abutment shoulder, which topside of the external abutment shoulder is beveled.

14. The adapter of claim 12 wherein the shaft reaches downwardly past the internal stop shoulder of the cup.

15. The adapter of claim 10 wherein the additional angled cleanout ports penetrate the exterior of the peripheral wall of the shaft at or adjacent a bottom end of sand trap annulus.

16. The adapter of claim 1 wherein the shaft terminates at a bottom end thereof inside the cup.

17. The adapter of claim 16 wherein the axial through bore of the shaft is upwardly tapered at a lower region thereof adjacent said bottom end of the shaft.

18. The adapter of claim 1 wherein the shaft and the cup are separately embodied but matable components, mated together by threaded engagement of external male threads on the shaft and internal female threads on the cup, at a location below the chambered upper portion of the cup.

19. The adapter of claim 1 in combination with the plunger and a top connector, of which the top connector is coupled, or adapted for coupling to, the rod of the downhole pump assembly, and the upper coupling portion of the shaft is coupled, or adapted for coupling to, the top connector for indirect connection of the shaft to the top connector through said adapter.

20. The adapter claim 1 characterized, at least between the top end of the cup and the sand trap shoulder, by lack of any means for sealed sliding contact with a pump barrel of the downhole pump for uninhibited admission of the second fraction of sand into the open annulus between the neck portion of the shaft and the chambered upper portion of the cup.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Preferred embodiments of the invention will now be described in conjunction with the accompanying drawings in which:

(2) FIG. 1 illustrates a downhole pump of the prior art that is equipped with a sand snare chamber.

(3) FIG. 2A illustrates a different downhole pump of the prior art.

(4) FIG. 2B illustrates a top plunger adapter of the prior art for use in a downhole pump of the type shown in FIG. 2A.

(5) FIG. 3 illustrates an improved top plunger adapter of the prior art usable in place of that of FIG. 2, and equipped with a radially floating sleeve.

(6) FIG. 4A is an assembled cross-sectional view of a top plunger conversion adapter of the present invention.

(7) FIG. 4B is another assembled cross-sectional view of the top plunger conversion adapter of FIG. 4A, in a different cross-sectional plane offset 90-degrees therefrom.

(8) FIG. 5 is a cross-sectional exploded view of the top plunger conversion adapter of FIG. 4.

(9) FIG. 6 is a cross-sectional view, in same plane as FIG. 4A, of a modified shaft component for a variant of the top plunger conversion adapter of FIGS. 4 and 5.

(10) FIGS. 7A and 7B illustrate additional variants of the top plunger conversion adapter of FIGS. 4 and 5, again in the same cross-sectional plane as FIG. 4A.

(11) FIG. 8A illustrates another variant of the top plunger conversion adapter of FIGS. 4 and 5, again in the same cross-sectional plane as FIG. 4A.

(12) FIG. 8B illustrates a further variant of the top plunger conversion adapter of FIG. 8A, in the same cross plane.

(13) FIG. 9 illustrates the top plunger conversion adapter of FIGS. 4 and 5 assembled with a conventional top connector and plunger in an installed state of the top plunger conversion adapter, ready for use.

DETAILED DESCRIPTION

(14) FIGS. 4A, 4B and 5 illustrate one embodiment of a novel top plunger conversion adapter 400 of the present invention that is installable, for example, between the top connector 156 and plunger 158 of the downhole pump of FIG. 2A, or between the alternative top connector 200 of FIG. 2B, if substituted for that of FIG. 2A, and the plunger 158. The top plunger conversion adapter 400 is designed to improve the downhole pump's ability to handle sand-laden fluids, but with a lesser part count than the sleeve-equipped prior art top connector 300 of FIG. 3. The present embodiment is referred to as a top plunger conversion adapter 400 because it is installed as an added conversion adapter to an existing top connector, such as that shown at 156 or 200 of FIG. 2A or 2B, to convert it into a sand capable top connector, instead of as a substitutable replacement of such existing top connector, like the prior art top connector 300 of FIG. 3. That said, in other embodiments, the inventive adapter 400 may alternatively incorporate the functional features of a top connector 156, 200 directly in the adapter 400, in which case the inventive adapter 400 may be employed as a substitute for, rather than an additional to, an existing top connector 156, 200, as shown in FIG. 9. Therefore, the inventive adapter 400 may be referred to herein generically as an adapter or top plunger adapter, regardless of whether it is installed in substitution for a top connector, or as a supplemental add-on thereto.

(15) The present embodiment of the inventive adapter 400 is a two-piece assembly, of which the first piece is referred to as a shaft component 402 (or simply a shaft, for brevity), and the second piece is referred to as a cup component 404 (or simply a cup, for brevity). The shaft 402 has a top end 402A and an opposing bottom end 402B, and an axial through-bore 406 passing axially through an entirety of the shaft 402 from the top end 402A thereof to the opposing bottom end 402B. An uppermost coupling portion 408 of the shaft 402 adjacent the top end 402A thereof is configured as an externally threaded male pin connection for threaded mating with an internally threaded female box connection at the bottom end of the top connector 156 or 200, where the plunger 158 would have conventionally been threadingly coupled directly to this top connector 156 or 200. A lowermost coupling portion 410 of the shaft 402 adjacent the bottom end 402B thereof is also externally threaded for threaded mating with an internally threaded portion of the cup 404, as described in more detail further below. The lowermost coupling portion 410 is of lesser outer diameter than the uppermost coupling portion 408.

(16) Immediately below the uppermost coupling portion 408 of the shaft 402, is a wide portion 412 thereof of greater outer diameter than the uppermost coupling portion 408 above it. The wide portion 412 is characterised by an annular stop shoulder 414 at its top end, attributed to the change in diameter from the smaller uppermost coupling portion 408 to the wide portion 412, which stop shoulder 414 abuts up against a bottom end of the top connector 156 or 200 when coupled thereto by threaded engagement of the shaft's uppermost coupling portion 408 therewith. Though not shown in the drawings, this wide portion 412 may feature opposing wrench flats thereon to enable tool aided rotation of the shaft 402 during assembly of the adapter 400, and during threaded coupling of the assembled adapter 400 to the top connector 156 or 200 at the uppermost coupling portion 408 of the shaft 402. Below the wide portion 412, the shaft 402 has a downwardly tapered portion 416 at which the external diameter of the shaft 402 gradually reduces moving axially downward therealong, before regaining uniformity of diameter and an axially adjacent over-shoulder portion 418 of the shaft 402.

(17) This over-shoulder portion 418 of the shaft 402 is referred to as such because it is immediately neighboured therebelow by a sand trap shoulder 420 that spans circumferentially around the shaft 402 and imparts a localized increase of external diameter to the shaft 402 relative to both the over-shoulder portion 418 situated above the sand trap shoulder 420 and a neck portion 422 of the shaft 402 residing below the sand trap shoulder 420. A topside 420A of the sand trap shoulder 420 is beveled, having an upwardly inclined slope toward the outer circumference of the sand strap shoulder 414. The outer diameter of the sand strap shoulder 420 may equal to that of the wide portion 412 of the shaft 402. The neck portion 422 and the sand trap shoulder 420 are joined via a flared transition 424 of upwardly flared profile that provides a gradual widening of the shaft 402 from the neck portion 422 to the sand trap shoulder 420, and which flared transition is concavely contoured in the illustrated embodiment.

(18) A plurality of angled cleanout ports 426 are provided in cooperative relation to the sand trap shoulder 420, and fluidly communicate the axial through-bore 406 of the shaft 402 to the exterior thereof by penetrating through a peripheral wall 428 of the shaft 402 that circumferentially surrounds, and thereby delimits, the axial through-bore 406 thereof. Each angled cleanout port 426 penetrates the exterior of the peripheral wall 428 of the shaft 402 just above the sand trap shoulder 420, and penetrates an interior of the peripheral wall 428, into the axial through bore 406 of the shaft 402, at a lesser elevation thereon than where the angled cleanout port 426 penetrates the exterior peripheral wall 428. Each angled cleanout port 426, for example, penetrates the interior of the peripheral wall 428 at an elevation equal to, or proximate, that of the bottom of the sand trap shoulder 420 or the flared transition 424. The angled character of cleanout ports 426 thus refers to an upwardly sloped inclination of each thereof in a radially outward direction from the axial through-bore 406.

(19) Further down the shaft 402 at the neck portion 422 thereof, one or more sand trap ports 430, of which there are two in the illustrated example, also penetrate through the peripheral wall 428 of the shaft 402 from the axial through bore 406 of the shaft 402 to the exterior thereof. These sand trap ports 430 are individually larger than the comparably small cleanout ports 426 at the sand trap shoulder 420, but are provided in lesser quantity than the comparably small cleanout ports 426, and therefore occupy positions of less densely spaced distribution around the circumference of the shaft. In the illustrated case of two such sand trap ports 430, they are distributed at equal 180-degree intervals around the shaft 402, whereas the illustrated embodiment has eight angled cleanout ports 426 distributed at equal 45-degree intervals around the shaft 402, denoting a more densely distributed layout in the circumferential direction around the shaft.

(20) In the present embodiment, the bottom end of the neck portion 422 of the shaft 402 is characterized by an external abutment shoulder 432 of greater outer diameter than the remainder of the neck portion 422 above this external abutment shoulder, but of lesser outer diameter than the sand trap shoulder 420. The purpose of this abutment shoulder 432 is to establish a fully mated position of the shaft 402 in its threaded coupling to the cup 404, where the external abutment shoulder 432 of the shaft 402 will abut against a corresponding internal stop shoulder of the cup 404 in the manner illustrated in FIGS. 4A and 4B, and described in more detail further below. In the illustrated example, the axial through bore 406 of the shaft 402 is downwardly tapered at a top region 406A of the through bore 406 that resides adjacent the top end 402A of the shaft 402, and is upwardly tapered at a bottom region 406B of the through bore 406 that resides adjacent the bottom end 402B of the shaft 402.

(21) Having fully described the geometry of the shaft 402, attention is now turned to the geometry of the cup 404, and the relationship between these two components 402, 404 in the assembled state of the novel adapter 400. The cup 404 has a top end 404A and an opposing bottom end 404B, the two of which lie oppositely of one another in an axial direction matching that in which the top and bottom ends 402A, 402B of the shaft 402 are of likewise opposing relation to one another. This axial direction is denoted in the drawings by a central longitudinal axis A.sub.L on which the shaft 402 and cup 404 are both centered in the assembled state of the adapter 400. The cup 404 features a chambered upper portion 450 having a hollow upper chamber 452 that is cylindrical in shape and fully open at the top end 404A of the cup 404. The diameter of the upper chamber 452, denoting the internal diameter of the chambered upper portion 450 of the cup 404, is larger than the external diameter of the neck portion 422 of the shaft 402. This enables receipt of the neck portion 422 of the shaft 402 into the hollow upper chamber 452 of the cup 404 in the assembled state of the adapter 400, as shown in FIGS. 4A and 4B.

(22) Below the chambered upper portion 450, the cup 404 features an internally threaded middle portion 454 of lesser inside diameter than the chambered portion 450. The internal female threading of this threaded middle portion 454 of the cup is matable with the external male threading of the externally threaded lowermost coupling portion 410 of the shaft 402, via insertion of the threaded lowermost coupling portion 410 of the shaft 402 through the open top end 404A and hollow upper chamber 452 of the cup 404 into the threaded middle portion 454 thereof. Owing to this difference in diameter between the chambered upper portion 450 and threaded middle portion 454, the cup 404 features an internal stop shoulder 456 at the bottom end of the hollow upper chamber 452. It is against this internal stop shoulder 456 that the external abutment shoulder 432 of the shaft 402 bottoms out when the shaft 402 and the cup 404 are threaded together into a fully mated state, thereby denoting the fully assembled state of the adapter, as shown in FIGS. 4A and 4B. Below the threaded middle portion 454, the cup 404 features a plunger coupling portion 458, which is another hollow female portion, like the chambered upper portion and threaded middle portion above it, so that the hollow interiors of the three portions of the cup cooperatively span a full axial length of the cup from the open top end 404A thereof to the open bottom end 404B thereof. In the illustrated example, the plunger coupling portion 458 is configured as an internally threaded female box connection of greater internal diameter than the threaded middle portion 454, and is thereby directly matable with a plunger whose top end is configured with an externally threaded male pin connection, such as the conventional plunger 158 shown in any of FIGS. 2A, 2B, 3 and 9. The plunger coupling portion 458 may alternatively be configured as an externally threaded hollow male pin connection for mating with a plunger whose top end is instead configured with an internally threaded female box connection.

(23) It will be appreciated that instead bottoming out of an external abutment shoulder 432 on the shaft with an internally shouldered bottom of the hollow upper cavity 452 of the cup 404, the cup may feature an internal stop shoulder at the bottom of its threaded middle section 454, at shown at 454A of the cup 404 in the variant adapters 400A, 400B of FIGS. 8A and 8B, for abutment thereof by the bottom end 402B of the shaft 402, in which case the shaft 402A, 402B may optionally omit the external abutment shoulder 432 at the bottom end of the neck portion 422, as likewise shown in FIGS. 8A and 8B. Among FIGS. 8A and 8B, FIG. 8B shows how the angled cleanout ports 426 need not be circular, oval-shaped or otherwise rounded in their cross-sectional shape, and for example could be slot-shaped in cross-section, with a slot-shaped profile that is notably narrower in the axial direction of the adapter than it is wide in the circumferential direction of the adapter. The narrow slot-shaped flow ports 426 could impart a more jet-like and effective cleanout action than the round holes of the other embodiments that of closer (if not equal) measure in the axial and circumferential directions.

(24) In the illustrated example, the cup 404 is externally cylindrica throughout its fully axial length, thus maintaining a uniform external diameter from the top end 404A of the cup to the opposing bottom end 404B thereof. This external diameter of the cup 404 denotes the maximum external diameter of the overall assembled adapter 400, whereby it is the cup 404 of the adapter 400 that is designed to reside in close proximity to the inside of the pump barrel 116 to achieve a fluid or hydrodynamic seal therewith.

(25) The inside diameter of the hollow upper chamber 452 of the cup 404 intentionally exceeds the external diameter of the neck portion 422 of the shaft 402, the purpose of which is leave an open annular gap between the shaft 402 and the cup 404 at the chambered upper portion 450 of the cup, which annular gap is also referred to herein as a sand trap annulus 460 of the adapter 400. The top annular rim of the cup 404 at the top end 404A thereof is a beveled edge 462, which like the beveled topside 420A of the shaft's sand trap shoulder 420, is angulated at a slope of upward inclination in radially outward relation from the central longitudinal axis A.sub.L. In the assembled state of the adapter 400, with the lowermost coupling portion 410 of the shaft 402 threaded into the internally threaded middle portion 454 of the cup 404, the neck portion 422 of the shaft 402 and the sand trap ports 430 therein reside inside the hollow upper chamber 452 of the cup 404.

(26) The shaft's sand trap shoulder 420 instead resides externally of the cup 404 in elevated relation above the open top end 404A and beveled top rim 462 of the cup 404. The sand trap shoulder 420 is intentionally of lesser external diameter of the cup 404 to leave flow clearance between the sand trap shoulder 420 and the pump barrel 116 to permit some amount of fluid found above the sand trap shoulder 420, and any sand contained in that fluid, to pass downwardly by the sand trap shoulder 420 to the preferably beveled top end 404A of the cup. At the same time, because the sand trap shoulder 420 is of greater exterior diameter than the over-shoulder portion 418 of the shaft 402 above the sand trap shoulder 420, a fractional portion of any such sand in the fluid above the sand trap shoulder can be captured atop the sand trap shoulder 420 and/or diverted into the internal through bore 406 of the shaft 402, and thus prevented from reaching either the cup 404 or the plunger 158 coupled to the bottom end 404B of the cup 404. Such capturing or diversion of a fractional portion of the sand by the cup-overlying sand trap shoulder 420 is made more effective by the preferably beveled character of the topside 420A of the sand trap shoulder 420, which encourages the sand radially inward, and thus away from the pump barrel 116.

(27) At the same time, because the sand trap shoulder 420 is intentionally smaller in external diameter than the cup 404, another fractional portion of the sand-carrying fluid above the sand trap shoulder 420 is intentionally permitted to pass downwardly by the sand trap shoulder 420 and onward to the preferably beveled top edge 462 of the cup 404, where this sand gets captured in the sand trap annulus 460 between the shaft 402 and the cup 404. The preferably beveled character of the top edge 462 of the cup 404, like the preferably beveled topside 420A of the sand trap shoulder 420, helps direct radially inward movement of the sand that bypassed the sand trap shoulder 420, thus directing such sand away from the wall of the pump barrel 116 and into the sand trap annulus 460 between the shaft 402 and the cup 404. Such collection of sand by the sand trap shoulder 420 and the sand trap annulus 460 typically occurs during the upstroke of the pump, and at times when the pump is stationary, during which sand can gravitationally settle out of the fluid situated above the sand trap shoulder 420.

(28) Between the top end 404A of the cup 404 and the sand trap shoulder 420 of the shaft, the adapter is completely void of any wipers or other means for making sealed sliding contact with the pump barrel wall, thus permitting uninhibited admission of the second fraction of sand into the open sand trap annulus between the neck portion of the shaft and the chambered upper portion of the cup. This, and the intentionally undersized character of the sand trap shoulder 420 relative to the external diameter of the cup 404 and the plunger 158 to specifically and intentionally permit a degree of sand passage downwardly therepast, runs contradictory of the prior art, where conventional thinking has been that in order to better prevent sand from reaching the plunger, the solution is the addition of wipers or other such sealing means to increase the overall quantity of sealed pump barrel contact above the plunger.

(29) During the downstroke of the downhole pump, fluid moving upward through the travelling valve travels up through the interior 159 of the plunger 158, and into the axial through bore 406 of the shaft 402 of the adapter 400, as permitted by the fluidically communicated relationship between the hollow interiors of the plunger coupling portion 458 of the cup 404 and the threaded middle portion 454 thereof, inside of the latter of which the open bottom end 402B of the shaft 402 resides in the adapter's assembled state. A fraction of this fluid moving upwardly through the axial through bore 406 of the shaft 402 is discharged therefrom through the sand strap ports 430 into the sand trap annulus 460 between the shaft 402 and the cup 404 at the chambered upper portion 450 thereof, thus helping flush out any sand that has accumulated in this sand trap annulus 460 and its flow ports 430. Likewise, a fraction of the fluid that passes onwardly up the axial through bore 406 of the shaft 402 past the sand strap ports 430 thereof during the downstroke of the pump is discharged from the shaft's axial through bore 406 through the angled cleanout ports 426 at the sand trap shoulder 420, to flush away any sand buildup that has accumulated at the sand trap shoulder 420 and its cleanout ports 426. During the upstroke of the pump, the relatively large sand trap ports 430 serve to draw sand toward or into into the axial through bore 406 owing to creation of a low pressure vacuum effect therein during the upstroke.

(30) The sand trap shoulder 420, with its exterior diameter being less than that of the cup 404, denotes a partial sand trap effective to capture a first fractional portion of the sand while permitting a second fractional portion of said sand to pass downwardly beyond the sand trap shoulder to the cup, where the second fractional portion of said sand is instead captured by sand trap annulus 460 cooperatively formed by the shaft 402 and the cup 404. The sand trap and the cup thus cooperatively inhibit or prevent downward passage of sand to the plunger. Should one sand trap become overly clogged to the point it can't be flushed clean during the downstroke, a degree of sand handling capability is nonetheless retained by the other unclogged sand trap. By distributing the sand handling functionality of the adapter 400 between the sand trap annulus 460 and the additional shaft-carried sand trap shoulder 420, beneficial results are seen in terms of the overall sand handling capacity, minimization of a total sand plugging risk and inclusion failsafe redundancy should either one trap individually become irreversibly plugged, all of which is achieved in a relatively simple assembly having only two component parts.

(31) FIG. 6 illustrates a modified form of the shaft 402 in which a set of additional angled cleanout ports 426, of the same type found at the sand trap shoulder 420, are included at the abutment shoulder 432 at the bottom end of the shaft's neck portion 422, the purpose of which is to improve the self-flushing cleanout of the sand trap annulus 460 between the shaft 402 and the cup 404 at the chambered upper portion 450 thereof. The additional angled cleanout ports 426 penetrate the exterior of the peripheral wall 428 of the shaft 402 inside the hollow upper chamber 452 of the cup 404, at or near the bottom end of the sand trap annulus 460, which in the illustrated example is denoted by a beveled topside 432A of the abutment shoulder 432. The beveled topside 432A of the abutment shoulder 432 is of downwardly declined slope in the radially outward direction, in opposition to the outwardly inclined slope direction of the beveled topside 420A of the sand trap shoulder 420 and the beveled top rim 462 of the cup 404. The additional angled cleanout ports 426 penetrate the interior of the peripheral wall 428 of the shaft 402 at a lower elevation than where they penetrate the exterior thereof, for example penetrating the interior of the peripheral wall 428 at an upper region of the lowermost coupling portion 410 of the shaft 402. The shaft variant 402 of FIG. 6 also differs from the earlier example in that the sand trap ports 430 are given an upwardly inclined orientation, like those of the smaller angled cleanout ports 426, 426 to impart an upward directionality to the fluid used to flush out the sand trap annulus 460 during the downstroke of the pump.

(32) FIG. 7A illustrates a variant 400 of the adapter 400 in which the shaft 402 of FIGS. 4A, 4B and 5 has been modified to reconfigure the uppermost coupling portion 408 of the shaft 402 as an internally threaded female box connection to enable direct coupling of the shaft 402 to the rod 154 of the downhole pump, instead of indirect coupling thereto through a top connector, such as 156 or 200. In this variant 400, the sand trap ports 430 and the angled cleanout ports 426 define the ultimate outlets by which the fluid travelling up through the plunger from the travelling valve ultimately exits the travelling assembly 150, instead of through outlet openings 213 in the top connector 156 or 200. FIG. 7B illustrates a similar variant 400 in which the uppermost coupling portion 408 of the shaft 402 of FIG. 6 has likewise been reconfigured as an internally threaded female box connection, and illustrates how the shaft need not have a full-length axial through bore spanning all the way to the top end 402A of the shaft in either variant of FIG. 7, as illustrated by a solid interior of the downwardly tapered portion 416 in the FIG. 7B variant. In this variant, it is the sand trap ports 430 and the two sets of angled cleanout ports 426, 426 that form the ultimate outlets of the travelling valve assembly 150. The FIG. 7B variant also illustrates how the second set of angled cleanout ports 426 need not necessarily reside directly at the bottom of the sand trap annulus 460, and need not necessarily penetrate through a top-beveled external abutment shoulder 432 of the shaft.

(33) Since various modifications can be made in the invention as herein above described, and many apparently widely different embodiments of same made, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.