US3168924A - Plastic well screen point - Google Patents

Description

Feb. 9, 1965 L. w. ANDERSON PLASTIC WELL SCREEN POINT 2 Sheets-Sheet 1 Filed May 10, 1963 INVENTOR. LOUIS W. ANomzsoN BY %%W j Feb. 9, 1965 L. w. ANDERSON 3,168,924

PLASTIC WELL SCREEN POINT Filed May 10, 1963 I 2 Sheets-Sheet 2 fiugn rum INVENTOR. Lows W. ANDEEsQN A TTOENE Y5 t t I United States Patent Ofitice 3,158,924 Patented Feb. 9, 1965 3,168,924 PLASTIC WELL SCREEN POINT Louis W. Anderson, 7 49 61st Ave. S., St. Petersburg, Fla. Filed May 10, 1963, Ser. No. 279,445 4 Claims. (Ci. 175314) This invention relates to apparatus for draining water from soil, and more particularly to well points.

A main object of the invention is to provide a novel and improved means for draining a well point, said means enabling a maximum quantity of water to be passed therethrough for a given diameter and length thereof, the screening means acting to block fine soil particles, thereby enabling relativelyclear water :to be produced through the associated well, the screen device being light in weight so that it is inexpensive to fabricate and to handle, being mechanically rugged, and being free of rusting or corrosive action.

A further object of the invention is to provide an improved plastic Well screen for use with a well point system, the screen being economical to manufacture and to transport, providing a high capacity of water flow therethrough, preventing the intake of air into the associated well, being easy to handle by workmen so that it reduces the possibility of accidents and minimizes the requirement for using heavy equipment, being nonconductive to electricity so that it is safe to. use when working under or adjacent'to power lines, being free of any tendency to form scale'or to develop electrolytic action, and being relatively chemically inert so that it will last indefinitely.

A still further object of the invention is to provide a novel and efficient jetting head associated with the well point screen structure, said jetting head having no moving parts and providing an efiicient and practical means for jetting the well screen structure into the ground.

A still further object of the invention is to provide an improved plastic well screen and meansfor drivingthe same into the ground. i

A still further object of the invention is .to provide a screened well point provided with an inner pipe extension device to prevent entry of air into the associated well piping caused by a dropping static water level, or caused by draw-down air intake due to heavy or prolonged pumping.

" Further objects and advantages of the invention will the present invention provided with a plastic drive point. In performing excavation work in areas where the water level is relatively high so as to interfere with excavating, it is a customary practice to sink a row of pipes by means of which the groundwater is pumped out and the excavation rendered possible. For this purpose, the pipes are provided at their lower ends with Well points, namely, devices carrying means for discharging water so as to facilitate the descent of the pipes by displacing the soil in the path of the pipes, and also including means for removing the subsurface water by pumping. For jetting action, namely, for projecting water from the pipes for the purpose of facilitating the sinking of the pipes, the water employed must be capable of passing freely from the bottom ends of the pipes into the subjacent soil, whereas for draining the soil, the water must be able to pass freely into the pipes at locations immediately above the bottom ends of the pipes for upward removal through the pipes. The pipes should be properly screened to block the entry of soil particles and so that acceptably clear water will be produced. Thus, it is highly desirable that the well screen employed with. a pipe expose the maximum amount of intake surface possible for a given diameter and length of screen, while suitably blocking the entry of fine soil particles. Also, it is desirable that the material employed for the screen be substantially noncorrosive and not subject to scale deposits, since corrosion and the deposition of scale would seriously impair the free flow of waterthrough the screen.

It will be understood that the screen structure presently to be described is applicable not merely with pipes .ot

become apparent from the following description and claims, and from the accompanying drawings, wherein: FIGURE 1 is a perspective view of an improved well screen assembly provided with a jetting head, constructed in accordance with the present invention, the parts being shown in separated positions, and certain parts being shown partly broken away.

, FIGURE 2 is a vertical cross sectional View showing a screened well assembly provided with a jetting head, as illustrated inFIGURE 1, installed in a Well bore, a portion of the screen assembly being broken away.

FIGURE 3 is an enlarged horizontal cross sectional View taken substantially on the line 33 of FIGURE 2; FIGURE 4'is a fragmentary vertical cross sectional view taken substantially on the line 4-}4 of FIGURE 3. FIGURE 5 is a fragmentary vertical cross sectional view of the lower portion of the assembly of FIGURE 4 with the jetting pipe removed. 1

FIGURE 6 is a perspective view of an inner pipe extension device which may be employed in a well screen assembly in accordance with thepresent invention.

1 FIGURE 7 is a fragmentary vertical cross sectional view, similar to FIGURE 4, but showing the extension device of FIGURE 6 installed therein.

FIGURE 8 is a fragmentary 'vertijcal cross sectional view of the lower portion of a well screen according to the type used with wellpoints but also with pipes employed in drilled wells for the purpose of producing water from the wells. I i

Referring to the drawings, 11 generally designates a typical screened pipe assembly accordingto the 1 present invention, adapted to beemployed in a well bore 12 in amanner similar to that above described. Thus, the as-' sembiy 11 comprises a rigid plastic tubular main body 13 formed with a plurality of relatively wide, closely spaced inlet slots-14, said slots extendinghorizontally and being as large as possible consistent with the maintenance of adequate structural strength for the tubular body 13. Cemented to the tubular body/ 13 and covering the slots 14 is a relatively coarse inner plastic screen 15. Ce-

mented over the inner screen 15 is a relatively fine gauge plastic screen 16,- and cemented over the fine gauge screen 16 is a relatively coarse gauge outer plastic screen 17.

The relatively coarse gauge outer screen 17 provides mechanical protection for the fine gauge screen 16 without substantially blocking its filtering surface. The inner coarse gauge screen 15 acts as a stable support for "the fine gauge screen 16 and as a free connecting channel means between the fine gauge screen 16 and the intake slots 15%. r

Byemploying plasticmaterials for the tubular member 13, and the screens 15, 1'6 and 17, no corrosion occurs and there 18 no tendency to form scale deposits. Consequently, the assembly has a long productive life and is not.

readily subject to clogging. If clogging should occur, the screen assembly maybe backwashed underwater pressure accompanied by acid treatments, or by other well known methods. 5 i

As shown in FIGURE 2, a coupling collar member 18 is secured on the topend of the tubular body 13, for connection to a pipe'section ,l lwhose lower end is secured in the upper portion of the'coupling collar 18 in a conventional manner. The pipe 19 may be connected to the intake ofa suitable pump, not shown, of conventional construction,

Cemented on the lower end of the tubular plastic rigid body member 13 is a plastic jetting annular casing or head shell Zil. Cemented inside the shell 24) approximately midway therein is a plastic ring 21. Cemented on the ring 21 is a plastic screen wafer assembly, designated generally at 22 and comprising a relatively coarse gauge lowercircular screen 23, a relatively fine gauge intermediate circular screen 24, and arelatively coarse gauge circular upper screen 25, the screens 23, 24- and 25 being all of plastic screen material. The coarse gauge screens 23 and 25 act as' reinforcing members, whereas the intermediate fine gaugescreen 24 acts as a filtering member.

Cemented in the shell 20 over the screen assembly 22 is a tubular adaptor member 26 comprising a cylindrical lower portion 27 provided with an outwardly extending bottom flange 28 and a reduced top portion 29 having external threads 30 adapted to be threadedly engaged in the bottom end of the jetting drop pipe 31 shown in FIG- URE 4. The member 27 is formed of plastic material, as is pipe 31.. As shown in FIGURE 2, the top end of the pipe 31rnay be connected to a pressure water supply pipe 32 for furnishing water under pressure to the pipe 31, for the purpose of jetting same through the filter assembly 22 and through the bottom end of the shell 2% into the bottom portion 33 of the excavation 12. As indicated in FIGURE 2, the water thus injected into the excavation flows upwardly through the bore 12 an emerges from the here at ground level.

FIGURE 5 illustrates the assembly with the jetting drop pipe it removed, whereby the assembly, including the jetting head shell 29 and its contents may be employed simply as a screened well pipe for filtering water drawn upwardly therethrough.

Referring to FIGURE 8, an alternate construction is illustrated wherein a hard-shatter-proof plastic, generally conical drive point 34 receives and is secured to the bottom end of the tubular body 13, being cemented thereto so as to be rigid therewith. The drive point 34 is provided with the cylindrical upper portion 35 forming a cylindrical cavity receiving the lower end portion of the tubular member 13, the drive point being formed'centrally of said cavity with the upstanding centering lug 36.

. A drive pipe 37 of metal or. similar hard material may be lowered inside the well pipe and the tubular member 13 and the lower end of the driving member 37 may be received in the annulardriving recess 38 defined around the upstanding projection 36.

It will be noted that when the method employing a drive pipe 37 is used to advance the screened well pipe .into the soil, the driving impact is delivered directly to the drive point 34 and there is no impact applied to the top end of the tubular body 13, thus preventing any tendency for the body 13 to collapse or telescope away from the screen elements 14, 15 and 16. As the well point is 'moved into the'ground under its driving impact, it opens a1 hole into which the well screen and associated mixing pipe are pulled, .being placed more under tension than under compression. Y

In the previously'described embodiment of the invention,'namely, the form illustrated in FIGURES 1 to 4, employing the jetting pipe 31, the boring action is provided by the jetting of the water under pressure downwardly into the excavation bottom 33, providing a hydraulic boring action which digs a hole into which the well assembly willfollow until the desired depth is reached, assuming that no impenetrable objects are encountered.

Referring to FIGURES 6 and 7, designated at 50 is a protective device which may be employed with the screened well pipe assembly of FIGURE where periodic lowering water tables would otherwise compel abandonmerit of the associated well during extreme periods of drougnL'or where the water table is excessively lowered by excessively high volume pumping to an extent'such that air may enter the top portion of the unprotected screened wellpipecausing the associated pump to be'par- 4, tially or totally deprimed. The entry of air into the top portion of the screened well pipe can cause damage to the pump as well as substantial loss of water.

The device 59 is adapted to serve as a downward extension of the connecting pipe 19 to a level below that of the water table. The extension device 59 comprises a cylindrical top member 51 slidably engageable inside the pipe 1% and provided with an annular sealing gasket 52 of resilient deformable material, such as neoprene, or the like, mounted in an annular groove formed in the lower portion of the member 51 and making sealing contact with the inside surface of the lower end portion of pipe 19, as shown in FIGURE 7. Secured in the cylindrical body 51 is the depending extension pipe 53 of substantial l ngth, the pipe 53, as well as the member 51 being made of plastic material. The member 51 is provided with the reduced externally threaded top portion 54 adapted to be connected to suitable lowering means, such as a connecting pipe for lowering the device 50 downwardly through the well pipe 19 to a depth such that the member 51 will be disposed within the upper end portion of the coupling member 13, and wherein the lower end ofthe drop pipe end of the screen assembly, as shown in FIGURE 7. v The gasket 52 provides suflicient frictional securement to prevent dislodgment of the assembly 5t under pumping conditions but will not prevent removal of the assembly 5% at some later time if so desired. When positioned in the manner above described and as illustrated in FIGURE 7,'the assembly 50 servesas an effective rechanneling device which requires the water entering the screened well pipe 13' to first flow downwardly toward'the lower end of the drop pipe 53 before it may be drawn upwardly into the well pipe 19. Thus,

the entry ,of air into the well pipe 19 is prevented as long asthe water table remains above the level of the bottom end of the drop pipe 53. i

It will be noted that the extensiondevice 59 may be employed in any type of well, either drilled, cased, jetted,

or driven, or wherever screens of any type are employed,

which are subject to the problem of possible entry of air due to a dropping water table.

It is tobe further noted that some wellscr eens fill up internally :with small particles of sand or other solid materials which are drawn into the well each timethe pump pulls, As long as the. movement of water in the vertical well pipe continues, no problem of immediate stoppage occurs, but each time the pump stops, the sand become plugged. The assembly .58 prevents this condi-I tion by requ ring that all water entering the well first sweep past the lower endof the well screen before enteringthe vertical well pipe. The jetting head assembly,

comprising the shell member 20 and its contents, also serves toprevent such plugging provided that its jetting screenassembly' 25 remains clean andactsas an additional intake'area at the bottom end of the well screen.

It is further to the noted that the jetting head assembly involves no moving parts. Prior art jetting headsemploying ball valves .or spring loaded check valves have developed considerable dilficulties in operationby sticking in closed positions or by being wedged open by rock fragments or other solids. No such difficulties are likely to be encountered with described."

FIGURE 7 illustrates a condition wherein the water table, shown at 60, has descended below the top portion of the screened well pipe, namely, has descended a sub 'stantial distance below the coupling memberlS, whereby air would enter thewellpipe without'the provision ofthe drop. pipe assembly 50. I

As this continues over a.

the jetting head assembly herein enessaa The slots in metal screens, as heretofore employed, tend to wear so as to greatly increase the sizes of the slots, due to the velocity of the water passing therethrough. A major portion of such wear occurs of the extremities of the slots.

Plastic well point tubes can only be slotted to a minimum Width of approximately 0.08 inch, which is too large to exclude objectionable solids. By employing inner and outer plastic screens, as above described, no limitation is placed on the size of the well point tube slots, and increased slot Widths may be employed, permitting larger volume of flow of water. The assembly is substantially unaffected by Wear and screens out all objectionable solids, for example, solids which are larger than those which will pass through a 120 mesh/inch screen.

While certain specific embodiments of an improved well screen and associated structure have been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. A well screen comprising a rigid tubular main body of non-metallic plastic material formed with spaced transverse slots of substantial width and distributed over the major portion of the length of said body, a relatively coarse gauge reinforcing first plastic screen secured on said main body overlying said slots, a relatively fine gauge filtering second plastic screen secured over said first screen, a relatively coarse gauge protective third plastic screen secured over said second screen, said screens allowing substantially free flow therethrough and through the slots but substantially preventing the passage of particles of solid material, an annular screen casing of plastic mate rial secured on the lower end portion of said main body, and a screen assembly extending transversely of the bore of and secured in said screen casing, said screen assembly comprising a coarse gauge plastic upper screen, a fine gauge plastic intermediate screen, and a coarse gauge plastic lower screen.

2. A well screen comprising a rigid tubular main body of plastic material formed with spaced transverse slots of substantial width and distributed over a substantial portion of the length of said body, a relatively coarse gauge reinforcing first plastic screen secured on said main body overlying said slots, a relatively fine gauge filtering second plastic screen secured over said first screen, a relatively coarse gauge protective third plastic screen secured over said second screen, said screens allowing substantially free flow therethrough and through the slots but substantially preventing the passage of particles of solid material, an annular screen casing of plastic material secured on the lower end portion of said main body, and a screen assembly extending transversely of the bore of and secured in said screen casing, said screen assembly comprising a coarse gauge plastic upper screen, a fine gauge plastic intermediate screen, and a coarse gauge plastic lower screen.

3. A well screen comprising a rigid tubular main body of nonmetallic plastic material formed with spaced transverse slots of substantial Width and distributed over the major portion of the length or said body, a relatively coarse gauge reinforcing first plastic screen secured on said main body overlying said slots, a relatively fine gauge filtering second plastic screen secured over said first screen, a relatively coarse gauge protective third plastic screen secured over said second screen, said screens allowing substantially free flow therethrough and through the slots but substantially preventing the passage of particles of solid material, an annular screen casing of plastic material secured on the lower end portion of said main body, a screen assembly extending transversely of the bore of and secured in said screen casing, said screen assembly comprising a coarse gauge plastic upper screen, a fine gauge plastic intermediate screen, and a coarse gauge plastic lower screen, said screen assembly including an upstanding conduit having an externally threaded top end, and a jetting conduit extending through said tubular main body and being threadedly connected on said externally threaded top end.

4. A well screen comprising a rigid tubular main body formed therealong with spaced transverse slots of substantial Width, a plurality of screens extending about said body in obstructing relation wiht respect to said slots, said screens being of different gauge and allowing substantially free fiow therethrough but substantially preventing the passage of particles of solid material, and a jetting annular casing depending from the lower end of said body, and a fixed screen assembly disposed Within and extending across said casing inwardly of the free end thereof, said assembly embodying a plurality of screens of diiferent gauge arranged in superimposed abutting relation.

References Cited by the Examiner UNITED STATES PATENTS 1,211,415 1/17 Cross -314 1,688,356 10/28 Romney 175-314 2,035,313 3/36 Grifiin 166-157 2,090,545 8/37 Moore 175-314 2,176,540 10/39 Moore 166-157 2,717,040 9/55 Paish 175-314 2,877,852 3/59 Bashara 166-230 2,969,840 1/ 61 DAudifiret et a1 166-227 2,985,241 5/61 Hanslip 166-2 0 CHARLES E. OCONNELL, Primary Examiner.

Claims (1)

1. A WELL SCREEN COMPRISING A RIGID-TUBULAR MAIN BODY OF NON-METALLIC PLASTIC MATERIAL FORMED WITH SPACED TRANSVERSE SLOTS OF SUBSTANTIAL WIDTH AND DISTRUBUTED OVER THE MAJOR PORTION OF THE LENGTH OF SAID BODY, A RELATIVELY COARSE GUAGE REINFORCING FIRST PLASTIC SCREEN SECURED ON SAID MAIN BODY OVERLYING SAID SLOTS, A RELATIVELY FINE GAUGE FILTERING SECOND PLASTIC SCREEN SECURED OVER SAID FIRST SCREEN, A RELATIVELY COARSE GUAGE PROTECTIVE THIRD PLASTIC SCREEN SECURED OVER SAID SECOND SCREEN, SAID SCREENS ALLOWING SUBSTANTIALLY FREE FLOW THERETHROUGH AND THROUGH THE SLOTS BUT SUBSTANTIALLY PREVENTING THE PASSAGE OF PARTICLES OF SOLID MATERIAL, AN ANNULAR SCREEN CASING OF PLASTIC MATERIAL SECURD ON THE LOWER END PORTION OF SAID MAIN BODY, AND A SCREEN ASSEMBLY EXTENDING TRANSVERSELY OF THE BORE OF AND SECURED IN SAID SCREEN CASING, SAID SCREEN ASSEMBLY COMPRISING A COARSE GUAGE PLASTIC UPPER SCREEN, A FINE GAUGE PLASTIC INTERMEDIATE SCREE, AND A COARSE GAUGE PLASTIC LOWER SCREEN.

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