US2042790A - Well point - Google Patents

Description

W. W. LEE

June 2, QSG,

WELL POINT Filed Feb. 18, 1935 Patented June 2, 1936 UNITED STATES PATENT OFFICE WELL POINT William W. Lee, Maywood, Ill.

Application February 18, 1935, Serial No. 7,001

'7 Claims. (C1. 166--5l '10 it rapidly and eiciently to drill into the soil,

ahead of the point, upon forcing fluid under pressure down through the same.

The various features of novelty whereby my invention is characterized will hereinafter be l pointed out with particularity in the claims; but,

for a full understanding of my invention and of its objects and advantages, reference may be had to the following detailed description taken in connection with the accompanying drawing, l wherein:

, Figure 1 is an elevation of a well point, one of the coupling elements being shown in section; Fig. 2 is a central longitudinal section, on a larger scale, through the lower end of the point,

the parts being in the relative positions assumed during a drilling operation; Fig. 3 is a view similar to Fig. .2, showing not quite the same fragment as does Fig. 2, the parts being inthe relative positions occupied during the times water is being Y .drawn up through the point and which are also the normal positions when the point is idle; Fig. 4 is a section on line 4-4 of Fig. 3, the wire mesh and perforated sheet metal sheathing which are vshown in Fig. 2 being omitted from this `view as is also the'case with respect to Fig. 3,; and Fig. 5 is a section on line 5-5 of Fig. 3. The well point as a whole, aside from the improved jetting means, may take any usual or preferred form since the present invention is not concerned with the details thereof. In the arrangement shown, there is a soil-piercing head I: vsecured to the lower end of a suitable tubular strainer element. The strainer element is illustrated as a piece of heavy pipe 2 screwed into the 5 head and lled with holes 3, a wire mesh layer 4 surrounding the pipe, and a sheathing in the form of a shell or sleeve 5 of thin perforated sheet metal surrounding the whole. As shown in Fig. 1, there is a coupling or union 6 screwed upon the upper end of the pipe 2 and, fixed in this member, is a tube or conduit 'I whose external diameter is considerably smaller than the internal diameter Aof the pipe 2. 'Ihe tube l is coaxial with the pipe 2 and extends down through the v latter into the vicinity of the head I. When a partial vacuum is created in the pipe 'I, through a connection with a pump or the like, while the point is immersed in water, water enters the lower end of the tube 'I and flows up through the latter. into the interior of the tubular strainer throughout the entire height of the latter, water is withdrawn from the bottom thereof only.

The upper half of the head I is bored out to a diameter suicient to receive the pipe 2 and therefore contains a chamber 8 of considerable size. There is an axial bore 9 extending from the bottom of the chamber 8 down through the nose or tip of the head. This bore is enlarged, beginning a short distance from the lower end, to receive a short tube I0 whose internal diameter is equal to that of the lower section of the bore. The tube I0, which may be a pressed fit in the bore 9, is long enough to extend up through the chamber and into the lower end of the tube l. The tube Ill is of smaller diameter than the internal diameter of the tube 'I.

Surrounding the lower end of the tube 1 is a long sleeve, II, held against rotation therein but slidable up and down on the same within limits. In the arrangement shown, the tube I has therein two diametrically opposed longitudinal slots I2, and the sleeve II has a pair of pins projecting inwardly into these slots. The pins may conveniently be screws I3, as shown. The length of the slots determines the distance through which the sleeve II may move up and down. The tube "I and the sleeve I I have therein large side openings I4, I4 and I5, I5, respectively; the combined areas of the openings in each being preferably greater than the crosssectional area of the tube l. These openings are so disposed that when the sleeve is lowered as far as it will go, solid or imperforate portions thereof cover the openings I4 in the tube 'I and imperforate parts of the wall of the said tube extend over the openings I5 in the sleeve, as indicated in Fig. 2; whereas, when the sleeve is moved up as far as it will go, each side opening in the sleeve registers with the corresponding side opening in the tube 'I, as indicated in Figs. 3 and 4. The member II may therefore be regarded as a sleeve valve.

The lower end of the sleeve valve, beyond the lower end of ythe tube 1, is thickened in the inward direction, as at I6, to produce an internal diameter only a little greater than the external diameter of the short tube I0. The said thickened part is of considerable axial length so as to Therefore, although water may flow provide a narrow annular space I'I of considerable length between the tube I0 and the thickened part of the sleeve valve.v

Below the sleeve valve, and surrounding the tube I0 within the chamber 8, is a compression spring I8 which tends constantly to hold the valve in its raised position. When water or other fluid under pressure is forced down through the tube I and reaches the tube I0, some enters the tube I0 and some passes down around the outside of the latter until it reaches the internal annular shoulder on the sleeve produced by the thickened part I6. A little of the fluid escapes down through the annular passage I'I, but the pressure of the remainder on the said shoulder drives the valve down, against the resistance of the spring, into the position shown in Fig. 2. Thereafter, as long as the downward flow of fluid under pressure is maintained, the valve will be held down by the pressure of the fluid; and, becausev the side openings in the valve and the tube 'I are closed, the only outlets for the fluid are through the jetting passage 9 in the headfand through the little annular passage around the tube I0 into the chamber 8 in the head. Much the larger part of the uid travels down through the jetting passage and drills or dredges out the soil bel-ow the head to permit the point to descend. The smaller stream, which is discharged into the chamber in the head, flows out through the strainer and acts in the manner of a lubricant to reduce the friction between the point and the surrounding soil.

It will be seen that by discharging a powerful jet straight down at the top of the device, the hole into which the well point 'descends may be driven very accurately as to direction 'and without requiring more material to be dredged out than is necessary to make a hole .of just the proper size. Thework of driving a well point Vmay therefore be done rapidly, accurately, and

with a minimum expenditure of power or energy.

As soon as the downward pressure of the jetting fluid stops, the spring lifts the sleeve valve and places the interior of the lower end of the tube I in open communication with the surrounding space within the strainer. Then, upon producing a suction in the tube 1, water will be drawn in from the lower end of the chamber within the strainer, through the registering openings I5 and I4, and up through the tube l; 'Ihe strainer has an effective water inlet area extending entirely around the same and from top to bottom; and, because the strainer element is usually several feet long, such'effective inlet area is many times that of the cross-sectional area of the tube 'I and still larger in proportion to the cross-sectional area of the jetting passage in the head. Consequently, water will not be drawn up through the jetting passage in the head but will be taken from the supply that seeps in throughfthe wall of the strainer. If it be desiredto provide a positive closure of the jetting passage except while jetting, a suitable upwardly seating check valve device may of course be arranged in the head in association with the jetting passage.

I have found that sometimes there is a tendency to build up a back pressure below the sleeve valve during jetting and thereby cause the valve to rise and permit the fluid under pressure to flow out laterally through the side openings I4 and I5. In order to prevent Ythis I place within the chamber in the head a cylindrical shell I9, surrounding and coaxial with the tube I0, this shell bottoming on the bottom wall of the said chamber and terminating at the top at such a level that the lower end of the sleeve valve will touch the upper edge of the shell when the valve is at the lower limit of its movement. The outer diameter of the shell is preferably at least as great as the corresponding diameter of the valve. The shell may be in the form of a cup, as shown, the bottom wall of which has a central opening just large enough to permit itto bepressed down over the tube I Il and be frictionally held thereby against accidental displacement.I The shell I9,

or the cylindrical wall thereof if the shell be cup-shaped, has large openings or windows 20 therein at a short distance above the lower end. 'Ihe water that escapes down through the annular passage Il, around the tube Il), during jetting, ows out through the openings 20 and up in the free space within the strainer `around the central pipes or tubes and the sleeve valve, and escapes through the perforations in vthe strainer.

-I do not know whether it is due to va kind of in- -jector action that the water in the shell I9 fails to exert any lifting elort on the sleeve valve I I; but, at any rate, the presence of the shell prevents the happening of the objectionable lifting of thevalve at times when it should remain down. i .f

It will thus be seen that a well point constructed in accordance with my invention may be like any ordinary well point having a central suction pipe extending down into the vicinity of the lower end of the strainer element, except that the head has a jettingpassage, that there is on said central pipe a sliding sleeve valve and that there are at most two little pieces of extra tubing fixed in theheadyso that the cost of a well point containing my improvements, Yover that of an ordinary well point, is very small. Also, because there is only a single movable part, the sleeve valve which is housed in and protected by the body of the well point, the device is sturdy and rugged and in no greater danger of being damaged or.v worn than is the simpler type o non-jetting well point. I'While I have illustrated and described with particularity only a single preferred form of my invention, I do not desire to be limited to the exact structural details illustrated and described; but intend to cover all forms and arrangements which come within the definitions of my invention constituting the appended claims.

I claim: r

1. In a vdevice of the character described, a tubular strainer element having at the lower end a soil-piercing head provided with a jetting passage, a tubev within and extending lengthwise through the strainer element to and in open communication with said passage, said` tube having a large side opening near the lower end, and means including a sleeve slidable on said tube to close said opening when fluid is forced down through the tube and to uncover the opening when fluid is drawn up through the tube.

2. In a device of the character described, a tubular strainer element having at the lower lend a soil-piercing head provided with a jetting passage, a short tube forming the inner end of said passage, a long tube of larger diameter than the short tube extending up through said strainer element in alignment with the short tube,.a sleeve mounted on the lower end of the long tube and telescoped upon the upper end of the short tube, said sleeve having at the lower end an internal annular flange surrounding the short tube, there being side openings in the sleeve and the long tube which register when the sleeve is moved up and are brought out of registration when the sleeve is moved down, and a spring tending to hold the sleeve up.

3. The combination with a device comprising a tubular strainer element having at its lower end a soil-piercing head provided with a jetting passage, together with a conduit larger in diameter than said passage extending lengthwise through said strainer element to said passage, of means including a spring and an element engaged with said spring and subjected to a differential pressure due to the difference between the diameters of said passage and said conduit automatically to shut off communication between the interior of the conduit and the surrounding space in the strainer element when fluid under pressure is flowing down through said conduit and automatically to establish such communication at all other times.

4. In a device of the character described, a tubular strainer element having at the lower end a soil-piercing head provided with a jetting passage, a tube within and extending lengthwise through the strainer element to said passage, said tube having a large side opening near the lower end, and means including a sleeve slidable on and having a contracted portion beyond the lower end of said tube to close said opening when fluid is forced down through the tube and to uncover the opening when fluid is drawn up through the tube.

5. In a device of the character described, a tubular strainer element having at the lower end a soil-piercing head provided with a jetting passage, a short tube forming the inner end of said passage, a long tube of larger internal diameter than the external diameter of the short tube extending up through said strainer element in alignment with the short tube, a sleeve mounted on the lower end of the long tube and extending downward from the same around the short tube, the lower end of the sleeve being contracted to an internal diameter only slightly greater than the external diameter of the short tube, there being side openings in the sleeve and the long tube which register when the sleeve is moved up and are brought out of registration when the sleeve is moved down, and a spring tending to hold the sleeve up.

6. In a device of the character described, a tubular strainer element having at the lower end a soil-piercing head provided with a jetting passage, a short tube forming the inner end of said passage, a tube smaller in diameter than the strainer element and larger in diameter than said short tube extending lengthwise through the latter and surrounding the upper end of the short tube, a sleeve valve on the lower end of the long tube projecting down below the latter and contracted at its lower end to produce between the same and the short tube a very narrow annular passage, the sleeve valve and the long tube having large side openings which register when the valve is raised and are covered when the valve is lowered, a spring tending constantly to raise the Valve, and a shell longer than and surrounding the short tube, the shell terminating at an upper level such that the sleeve valve contacts with the upper end thereof when lowered, and there being outlet ports in the lower end ot the shell leading into the space within the device around the shell.

'7. In a device of the character described, a tubular strainer element having at the lower end a soil-piercing head provided with a jetting passage, a tube of larger internal diameter than said passage within and extending lengthwise through the strainer element to and in open communication with said passage, said tube having a large side opening near the lower end, a sleeve valve on said tube to control said opening, said sleeve valve having an annular internal shoulder forming a closure for the lower end thereof, said shoulder surrounding said passage and being subjected to the pressure of jetting fluid flowing down through said tube and into said passage.

WILLIAM W. LEE.

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