US1733953A - Well casing and method of sinking - Google Patents

Description

Oct. 29, 1929. G. EVANS WELLIIASING AND METHOD OF SINKING Filed Oct. 25, 1928 gwumtow Ga/en 6mm I Patented Oct. 29, 1929 UNITED STATES GALEN EVANS, OF SHELTON, NEBRASKA WELL CASING AND METI-IGD OF SINKING Application filed October 25, 1928. Serial No. 314,936.

My invention relates to well casings and to the methods of sinking well casings.

One of its objects is the provision of a novel well casing possessing str ctural advantages over other well casings and capable of being produced on the job and largely from mate rials taken from the well cavity.

Another of my objects is the provision of a novel method whereby the well casing is armed to sink in a substantially radial direction of its own weight and the weight of its contents.

The novel method of sinking the well casing also contemplates the provision of a step whereby the internal pressures will substantially balance the pressures on the outside of the casing so that the casing cannot be crushed during its sinking.

Another of my objects contemplates the step in the method whereby the excavated subsoil is returned to the well cavity during the sinking of the casing and the provision of bailles for keeping the splash away from the casing.

Another object which 1h ave in view in connection with the novel method is the provision of a retaining casing passing through the surthe soil and through portion of the sand and gravel ant extending below the water level.

Another at my ol jects is the provision of a floor "for the casing with a suction pipe pr. jecting tl'icrethrough for withdrawi the w ter and sand in advance of the sinlnn the casing.

Still another object is the t oision of a pipe and whereby the w and sand within the caci g may be wit id. awn after the casino; has bee ,sunlrt the desired d Having in view these objects OtllCiS which will be pointed out in the following description, I will now refer to the drawings, in which Figure l is a median vertical sectional view of the well casing during the process of sinln ing and showing also the relation oi the well to the retaining casing and to the soil layers.

Figure 2 is a median vertical sectional View of the lower end of a similar casing showing a somewhat modified form of floor.

Figure 3 is a median vertical sectional View on a somewhat reduced scale of a portion of the casing showing particularly the sealing plug applied between the casing and the re taming wall after the casing has been SllIlh and after the contents of the casing have been removed.

Fi ure SA is a median vertical sectional view similar to Figure 2 but showin the form of floor adapted for loosely receiving the lowermost section of tubing.

i gure l is a view in enlarged scale showing the gate and the operating mechanism whereeontents ot' the well casing may be the pumped. out after the casing has been sunk to the desired depth.

Both the casing and the method have been designed with particular reference to certain soil conditions. As shown in Figure 1, the soil has a top layer of clay underneath which a layer of sand and gravel. The water mratum is within the sand and gravel, the water level being shown at the line A-A. l l hile the casing and the method hereinafter descr bed are applicable to many other kinds of soils they are particularly adapted for use in soils of the kind described.

The casing 10 is preferably made by cementh together gravel which is small enough to pass through a 3 mesh screen and too 1 go to pass through a 16 mesh screen. Such gravel makes an ideal water filter if it is not permitted to become clogged with fine sand or other material filling the voids. Such material is frequently used for surrounding metallic or wooden well casings for the purpose of preventing line sand from reaching the well casing. It has heretofore been impossible to use such gravel as the material out of which the well casing itself is constructed because the mass of gravel has no definite form. I overcome this objection by the use of Portland cement in such minute quantities that the cement merely causes the gravel particles to firmly adhere to each other. Great care must be employed so as not to fill the voids or any appreciable portion of the voids between the particles of gravel since such filling would destroy the eltect-iveness of the well casing as a filter. The well casing may be cast in forms and as subsequently described it may be formed on the 3' ob and almost exclusively from materials taken from the well cavity.

In my method of sinking the well casing l first sink a retaining casing 11 through the top soil and into the sand and gravel so as to extend below the water level. This I do by first excavating to a sufiicient depth by any of the common and well-known methods. The casing 11 may be made of any suitable well casing material or it may be made of solid material since it does not extend to an appreciable depth below the water leve To function as a lilter for introducing water into the cavity after the well is in operation, the retaining wall 11 may be of a lean concrete mixture but'since only a small portion projects below the water line and since considerable strength in the retaining wall requit-ed. it is best to use some more suitable material. The initial step of sinking the retain'ing wall 11 leaves'a lined cavity eictendin from the surface of the soil to within close proximity to the water line and this cavity is used very largely for carrying on the operations of sinking the well casing.

The well casing 10 is preferably formed by casting in the manner above described and the cavity inside the retaining casing 11 is used for this purpose. The intit'ial s when of the casing 10 is cast with the floor 12 integral therewith and having a section of tubing 13 projecting therethrough, or it may be cast with an aperture for the reception of a section of tubing. The initial section of tubin with the floor 12 is formed within the cavity with the floor resting on the surface of the soil in the cavity at or near the water line. Other sections of tubing similar to the section 13 are then added. The beams or other supports 1% are then placed across the top of the cavity to rest on the top edge of the retain' g wall 11, these beams being used for the support of the pump The pump 15 may be a centrifugal pump as shown in the drawin or it may be a pump of intern'iittent type commonly known as sand pump or sand bucket. It should be positioned as closely a possib e to the water line so as to reduce the lift of the water bearing gravel and san It may be driven "from an engine pos ioned entirely outside the well casing or the engine itself may be placed in close proximity to the pinup and inside the cavity. The pump is provi "l with. a suction pipe 16 which tel opes the pipe 17, the pipe 17 being sectional projecting to'a slight distance below the tloor 12. It should be noted that the tubin l3 and the pipe 17 areeach formed of int 1 ing sections of any desired type so t t may be extended as the well casino pipe 16 is the suction pipe for Nib i and the sand and gravel. from beneath the floor 12 and carrying it through the pump and through the goose neck 18 into the well. The reason for forcing the water bearing sand and gravel into the well is that the highly porous well casing above described does not have sullicient strength during sinking to withstand the external pressures together with. the friction in sinking. The pressure of the water and sand inside the casing thus balances the external pressures so that the casing cannot be crushed. Another very important advantage of having the water, sand and gravel inside the casing is that it adds weight to the casing exerting a force on the iloor 12 and the casing wall 10 to cause the casing to sink as the material beneath it is removed rough the pump 15. The operation of the np 15 quickly causes the casing to sink its full length into the soil when another section must he added above the initial section and tubing 13 must be extended accordingly. 1. he sections of the casing 10 may be separate, bu it is preferable that they be of monolithic construction.

The method of sinking the well casing as above deszribed makes it an easy matter to provide a well casing of monolithic construction with very little difliculty and at practically no expense for materials.

The water, sand and gravel passing through the goose neck 18 may be strained so that the water and fine sand all pass down into the well cavity leaving the coarser material in the strainer 19. This strainer is shown in a conventional term since any strainer suitable for the purpose may be employed for separating the coarser gravel from the water and liner materials. The strainer 19 may be withdrawn at intervals so that the contents may be run through an 7 other strainer to separate the larger particles which are too coarse for use in the construction of the casing 10. The water and the gregate are thus hoth obtained from the well cavity from materials which must of necessity be handled anyway so that the labor cost well as the material cost is almost insignificant. The only thing needed in addition to those taken from the well cavity is a very small. quantity of Portland cement which. may be mixed with. the aggregate and moistened and then cast into the forms so that the sinking and the casting of the well casing are simultaneous. In fact the continuous addition to the length of the well casing increases its weight tion of the moist material in the well casing so that in some instances it may disturb the equilibrium outside the well casing and inside the retaining casing so that there is dang r that the space will become partly filled with sand and gravel which tend to back up under the disturbance. The agitation is, of course, least when a centrifugal or other continuous pump is used but it becomes very great when a pump of the intermittent type is employed. For this reason I provide cylindrical baflies 2O suspended by ropes from the beams 14, the baffles being designed to check the agitation of the material at the casing 10. Likewise I provide other cylindrical baffles 20 surrounding the tubing 13 and suspended so that their up per eoge is at a lower level than the lo or edge of the batlies 20. In this manner I control all violent agitation which might disturb the operation of sinking the well casing.

During the sinking of the well casing the lower extremity of the pipe 17 extends to some distance beneath the floor 12. As the water bearing sand and gravel are drawn through the pipe 17 a conical shaped hollow space is constantly formed beneath the well casing thus permitting the gradual sinking of the well casing. The lower end of the pipe 17 must be slightly above the sand and gravel as it would otherwise become choked, thus temporarily stopping the operation of the pumping of water bearing sand and gravel. In some cases itis desirable that the floor 12 be slightly modified for at least partly filling up the vacant space underneath the floor. In Figures 2 and 8A I have shown two such modifications. In both the floor is materially thickened in its middle portion and the oral shape of the flooris conical. The floor 12 of Figure 2 is formed with the lowermost section of the tubing 13 cast therein. The floor 12 provided with an axial opening for permitting the lowermost section of the tubing 13 to pass therethrough but the figure shows this opening to be plugged up for reacans subsequently explained.

W hen the well casing 10 has been sunk to the desired depth it becomes necessary to remove the from its interior. During the sinking of the well casing this sand functo maintain t ie internal pressure against the friction and outside pressure against the well casing, but its important function is to add su'l'li'ient weight to cause the well casing to sink under its own weight as rapidly as the withdrawal of the water bearing sand and gravel underneath the floor permits. After the well casing has been sunk, the friction against the exterior surface is entirely absent iat it does not require internal pressures to prevent the collapse of the well casing. The additional weight is also not further required since the well casing is to remain stationary after it has been sunk to the desired depth.

For removing the contents of the well with the least possible effort I provide an opening at 21 in the casing 13. This opening should be at or near the lower end of the tubing 13 inside the well cavity. During the sinking of the Well this opening is kept closed by a slidable gate 22 having a rod 23 secured thereto. This rod may be positioned inside the tubing 13 but if it is placed outside it must be protected by a special pipe 24: for reducing friction during the opening of the gate. The lower end of the pipe 24 must be spaced from the gate 22 at least a distance equal to the height of the opening 21. After the sinking of the well casing it is an easy matter to open the gate 22 by drawing up on the rod 23 and it will be evident that this action will cause the sand and water to flow through the opening 21 and into the cavity beneath the floor 12 of the well casing. It will also be evident that the operation of the pump 15 will then cause this sand and water to be drawn up through the pump 15. he contents of the well casing include only water and sand since most of the coarser particles have previously been removec by means of the screen 19 so that the flow through the pump will be rapid. This sand must, of course, he delivered outside the well casing but this may be done by replacing the goose neck 18 with a discharge pipe 25 for carrying the sand and water outside and away from the well casing.

After the contents of the well casing have been removed and before the soil water has been permitted to flow into the well through the casing 10 the opening in the floor 12 must be plugged up so as to keep out the sand. This is done by first disconnecting the sections of tubing 13 and pipes 17 and then filling the opening with lean concrete. lVhen the floor has been cast with the lowermost section of the tubing 13 this section is left in place and is then merely filled with concrete. When the floor has been cast with opening large enough for the tubing 13 to slide there through, as in Figure 3A. the tubing is removed and the concrete is thrust into the opening. At this of the sinking of the well casing the upper edge of the well casing will be at or near the water level. and a plug must also be formed between the retaining wall 11 and the casing 10 as shown in Figure This should be done to prevent the sand and gravel from entering the. casing over its top edge. The well is then completed and it requires only the removal of the tubing 18, the pipes 17 and the pump 15 with its connections and supports after which the well is ready to he placed into use.

From the foregoing description it will be evident that I have evolved a novel method for sinking well casings the method having numerous advantages over prior methods. Most of the prior methods contemplate the sinkin ot the well casing without a floor but with the application oi: sullicient weight or pressure to "force the well casing to the required depth in sand and gravel. This is usually done by applying heavy weights at the top oi the well asing. One difficulty with such a method is that the weights must be removed each time it is desired to add a section oi casino. The great drawback, however, is that it is impossible to properly balance such a weight and the result is that the casing); almost invariably will assume an inclined position when differences in the texture of the soil and sand strata are encountered. The prior methods are also counter to the principle that the friction increases to enormous extents in accordance with the depth to v. rich the well casin is sunl. Piles and piers for bridges and large building; structures are frequently used as supports, these piles or piers being merely sunk in the soft sand to a distance where they are firmly held by the friction and pressure of the sand. in well casings having no bottom. however, the friction and pressure is exerted on both the inner and the outer sum": res of the cas n so that it becomes almost impossible to sink the casi no; to an eitective depth. In the prior method, the weight of the load on the top of the casino is increased for forcing the casino; downwardly. Regardless of the form of well casing used there is a limit to its crushing: streuoth and this limit far hel ow the crushing effect of weight great enough to force the well casing down. lVith my method, on the other hand, the friction is entirely eliminated from the interior of the well casing, the exterior friction balanced by an excess ot inti 'nal preseaire and the weight is added proo'ressive and to the bottom of the well casino; so that its center of gravity is maintained at the lowest possible point. The result of this that the well casing; may be apidlv and easily sunk without danger of its use-aiming an inclined position.

While my primary object is the provision oi a. method for sinking wells, it is obvious that the method has somewhat wider range of usefulness. In H e proper soil condition the method would be equally effective for sinking; caissons, piers or piles and I therefore reserve to my. the right to the use of the method for all such purposes.

lVhile the above described method was designed particu arly for use in certain kinds oi soil involving large quantities of quick sand or the like. it obvious that the method of sinking well casinos is of much wider applicability and I thorn. re wish it to be understood that the word soil as used in the 'api'iended claims refers to any soils or combination of soils in which the method can be well casing may be so great that the well casing would not sink rapidly enough unless additional soil were put into the Well casing so as to give the casing sutlicient weight to overcome the friction of the surrounding soil. For this reason it may be necessary in some instances to raise the level of the soil within the casing during sinking to a considerable height above the water level. This can safely be done without'danger of bursting the casing since that port-ion of the casing which is subjected to the greatest internal pressure is seated deep in the soil. It is also apparent that the tubing 13 may be any one of a variety or" forms. For ease in manipulation, the sections must be interlocking. It is desirable, however, that the water from the Well casing seep through the tubing 13 and this may be done by employing sections of sheet metal Well tubing or by providing loose joints or in a niunher of other ways so that there will be a downwart flow oi water through the tubing 13.

aving thus described my invention in such tull, clear, and exact terms that its Lion and operation will be readily undemc-ood by others skilled in the art to which. it pertains. what i claim as new and desire to secure by Letters Patent of the United States is:

l. The method of forming and sinking a well casing, the said method consisting in forming the initial portion of the well casing with a bottom closure therethrough by castin a mixture of course gravel with a minute quantity of cement in excavating the soil berea ih said bottom closure, in conveying the soil thus excavated through the aperture in l bottom closure in separating: the coarse k vel from the sand'and water in said well casing; and in us ng the gravel thus separated for forming: add ional portions of the well casing. and finally in removing the soil from within the well casingafter said well casing has been sunli to the desired depth.

2. The method of sinking: a well casing having a bottom closure with an aperture much, th said method consisting in prevu ice tube communicating with the aperture in. said bottom closure and projecting); above the water level of the surroundin j soil. in providing; a ie within said tube in withdrawing; the soil and water -from beneath said well casing through said pipe and delivering the soil and water into said well casino on the outer side of said tube, and finally in discharg ng; the soil and water from the interior of. said well easing into the cavity beneath said bottom closure and witlr drawing the soil and water from the cavity beneath said bottom closure through said pipe and discharging it outside of said well casmgr.

In testimony whereof I aiiix my signature.

GALEN EVANS.

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