US2027398A

US2027398A - Well-point

Info

Publication number: US2027398A
Authority: US
Publication date: 1936-01-14
Anticipated expiration: 1953-01-14

Description

WELL POINT Filed NOV, 20, 1935 [X'LTHRWEEYS Patented Jan. '14, 1936 UNITED STATES PATENT OFFICE WELL-POINT Thomas F. Moore, Morris Plains, N. J. Application November 20, 1933, Serial No. 698,799

19 Claims.

This invention relates to certain improvements in well-points of the class set forth in my Patents Nos. 1,570,697, January 26th, 1926; 1,648,587, November 8th, 1927; 1,657,684, January 21st, 1928; and 1,729,790, October 1st, 1929; and also in my pending application Serial No. 644,482, filed November 26th,. 1932 maturing into Patent No. 1,959,174, granted May 15, 1934.

These well-points are adapted to be sunk to any required depth into and around a limited area of water-containing soil and connected individually or in multiple with a suitable suction pump or other device whereby the water content of the soil may be conveniently and expeditiously displaced to some remote locality in preparation for excavation and erection of subsurface Or super-surface structures within and around the dehydrated area.

The conditions of the soil into which these well-points are sunk varies greatly in different localities and also at different depths in the same locality and while it is possible to use well-points of relatively large diameter in some soils such as silt, sand and other more or less loose earth, the same well-points would be impracticable in the harder soils such as clay, shale and the like without the use of extra tools and machinery such as hole punchers of the class set forth in my Patent No. 1,906,706, May 2nd, 1933, and extra high-pressure pumps usually of the multistage centrifugal type all of which delays the progress and greatly increases the cost of the work.

The main object of the present invention is to provide a simple, practical and efficient wellpoint of appreciably less cross-sectional area than has heretofore been practised without reducing the effective intake area of the screen or jetting area of the interior pipe so that it may be sunk into and through practically all soil conditions under its own weight aided by occasional turning movement about its axis and also by jetting water or other fluid therethrough and thereby to avoid the delays and excessive expense incidental to the use of the extra tools and extra high-pressure pumps referred to.

In other words, I have sought to simplify the method of removing the water from the soil within restricted areas through the use of a specially constructed well-point which is capable of being sunk into widely varying soils to any required depth and attached to the usual fluidpressure and suction devices without the use of extra tools or machinery.

One of the specific objects is to construct the well-point so as to afford relatively large intake and jetting capacities within a relatively small cross-sectional area and thereby to enable the well-point to penetrate soils which would otherwise be diflicult of penetration by the usual jetting methods heretofore employed.

A further object is to prevent premature entrance of the air from the outside to the interior of the well-point before the external ground water has been lowered by suction to the level of the upper end of the lower cage pipe and thereby to assure the withdrawal of the water from the adjacent ground to at least that level when the suction device is in operation.

Another object is to provide the well-point with a tubular screen extending the major portion of the length thereof around and in spaced relation to the inner pipe and within the outer cage unit where it is protected from direct contact with the surrounding soil to allow the passage of the water therethrough to the inner pipe during the suction operations.

Additional objects are to provide the wellpoint with separate check-valves, one for checking the passage of the jetting fluid from the lower I end upwardly around the outside of the inner pipe during the jetting operation, and the other for preventing the entrance of sand, stones and other solid objects into said inner pipe and suction pump during the operation of withdrawing the water from the soil.

Other objects and uses will be brought out in the following description.

In the drawing:-

Figure 1 is a side elevation of a well-point embodying the various features .of my invention, the central portion thereof being broken away.

Figure 2 is an enlarged longitudinal vertical sectional view, partly broken away, taken on line 2-2, Figure 1.

Figures 3, 4 and 5 are transverse sectional views taken respectively in the planes of lines 33,

44,, and 55, Figure 2.

As illustrated, this well-point may be of any suitable length and preferably consists of an outer cage unit I, an inner jet-and-suction unit 2, and an intermediate tubular screen unit 3 arranged one within the other about a common axis and operatively connected to each other in a manner necting ring or head 6, a lower head or pipe section I, and a multiplicity of lengthwise reamer bars 8 arranged in uniformly spaced relation circumferentially around the outside of the tubular screen 3 in radial spaced relation thereto and having their upper and lower ends welded or otherwise rigidly secured to the upper ring 6 and to the lower pipe section 1 respectively, thereby establishing rigid connections between the ring 6 and pipe 1 in which the bars 8 serve the double purpose of reaming and enlarging the hole as the well-point enters the ground and also of protecting the screen against direct contact with the soil.

These bars also serve to rigidly hold the ring 6 and pipe 'I in axially spaced relation and as shown in Figure l are slightly bowed outwardly midway between their ends to enable the well-point to more easily enter the soil and to slightly enlarge the hole midway between the ends of the wellpoint during the descent thereof, the reaming operation being performed by angular movement of the well-point through the medium of any wellknown turning device, not necessary to herein illustrate or describe.

The upper end of the ring or nipple 6 is reduced in diameter and threaded externally for engagement with the lower internally threaded end of the coupling 4 which extends upwardly some distance above the nipple 6 and preferably has its lower end engaged with the upper ends of the bars 8.

The internal threads of the coupling member 4 extend to the upper end thereof for receiving and engaging the lower end of the pipe 5 which latter may be extended upwardly to any required length for connection with a suction pump, not shown, or with a source of fluid supply under pressure.

The portions of the bars 8 between the upper end of the pipe 1 and lower end of the nipple 6 are reinforced and held in uniformly spaced relation circumferentially by tie rings 9 which are arranged in uniformly spaced relation axially of the well-point and are welded or otherwise rigidly secured to the inner faces of the adjacent portions of the bars, thus forming a part of the cage structure.

These rings 9 extend around the periphery of the adjacent portion of the screen 3 in radially spaced relation thereto and serve to hold the bars against contact with the screen and also to assist in preventing undue pressure of the surrounding soil against the screen, it being understood that the spaces between the bars and also the spaces between the rings permit the ground water to readily pass therethrough and thence through the screen and thereby to facilitate the removal of the water from the ground by suction in a manner hereinafter more fully explained.

A tubular cutting or jetting section I ll of hard ened steel or equivalent material is inserted from the underside upwardly into the lower end of the pipe section I and is rigidly secured thereto by a rivet II or equivalent fastening means to form a unitary part of the cage, the upper portion of the section I being reduced in diameter to form a shoulder I0 abutting against the lower end face of the section I to assist in holding those parts in rigid relation.

The lower end face of the cutting or jetting section I0 is serrated to form teeth I2 to assist in cutting away the soil as the well-point is turned by hand or otherwise about its axis during its descent into the ground, the spaces between the teeth also serving to permit the passage of the jetting fluid from the interior to the exterior of the well-point around the lower end thereof.

The section I0 extends some distance above the rivet II and is provided with an internal valve chamber I3 for receiving a spherical float valve I4 and a support i5 therefor, the purpose of which will be hereinafter more fully described.

The upper end of the section 40 terminates some distance below the lower end of the inner pipe of the unit 2 and is provided with a plurality of, in this instance four, upwardly projecting ribs I6 arranged in uniformly spaced relation circumferentially to form intervening fluid passages I6, as shown by full lines in Figure 2 and by dotted lines in Figure 4.

The upper surfaces of these ribs forms a seat for receiving and supporting a ring valve I! in vertically spaced relation to the bottom walls of the passages I6 to avoid obstructing said passages when the valve is at rest upon its seat for a purpose hereinafter described.

The inner unit 2 comprises a cap section I8 and a central pipe section I9 extending through a central opening in the cap section I8 and having its upper end swaged outwardly and welded or otherwise secured to the cap section to form a unitary part thereof.

The cap section I8 is provided intermediate its ends with an outwardly projecting annular flange adapted to rest upon the upper end of the nipple 6, the portion of the cap below the flange being of slightly less diameter than the interior diameter of said nipple into which it is adapted to be inserted forming with the nipple an annular groove 28 for the reception of the upper end of the screen 3.

The upper portion of the cap I8 is also reduced in diameter and preferably tapered for receiving a gasket or packing ring 22 which is seated upon the upper face of the flange 29 between the reduced upper end of the cap I8 and inner periphery of the coupling section 4, as shown more clearly in Figure 2.

A packing washer 23 is supported upon the upper face of the gasket 22 and is tightened against said gasket by means of a ring-nut 24 engaging the internal threads of the coupling section 4 to form an air-and-liquid tight joint between the coupling section of the cage unit I and the cap section of the inner unit 2, as shown in Figure 2, said ring-nut being provided with suitable means for engagement with a spanner wrench or equivalent device for tightening and loosening the same.

The central pipe section I9 extends from the upper end of the cap section I8 downwardly into and below the upper end of the lower pipe section I in radially spaced relation thereto and has its lower end provided with an outwardly and upwardly inclined flange 25 forming a valve seat for the ring valve I! when the latter is raised from its supporting ribs I6, in a manner presently described.

That is, the lower end of the inner pipe section I9 terminates a relatively short distance above the upper face of the valve ring I1 when the latter is resting upon the ribs I6, thus permitting a limited vertical movement of the valve ring from its normal position of rest into engagement with the lower face of the annular flange 25, see Figure 2.

A plurality of, in this instance four, lengthwise ribs or bars 26 of U-shaped cross section are welded or otherwise rigidly secured to the outerperiphery'of the innerpipeisection I9 to project outwardly therefrom across the inter- -vening space between said inner pipe section andthe inner face of the screen 3,-said ribs being arranged in uniformly spaced relation circumferentiallyabout theaxis of the inner pipe I9 with their opposite flanges substantially radial to said axis and the outer edges of the flanges offsetcircumferentially at 26 and loosely engaged with the, inner periphery of the screen to assist in holding the screen in concentric relation to the-inner pipe as shown more clearly in'Figure 3.

The tubular screen 3 is preferably made of relatively fine ,mesh'wire having its upper end fitted rather closely and tightly within the annular channelzl between the nipple 5 and capsection 18 which serve to hold the screen in concentric relation to the axis of the well-point and also in radially spaced relation to the inner pipe section I9 and bars -8 of the outer cage unit, and permits it to ,be removed for repacking or replacement.

The'lower end of the screen is closely-fitted within the upper end of the lower pipe section I of the cage unit I and is reinforced by a relatively thin but strong metal band or ferrule 21 inserted in the lower end thereof, the outer edges of the opposite flanges of the channeled ribs 26 being recessed at 28 to receive the band 27 which is preferably mounted upon the outer edges of the adjacent portions of the channeled ribs'26 and may be welded or otherwise secured thereto, if desired.

If necessary, the upper end of the screen 3 may be soldered or otherwise attached to the periphery of the lower reduced portion of the cap I8 to form a part of the inner unit 2 so that the latter with the screen thereon may be withdrawn upwardly from the interior of the cage unit for repairs or replacement when required in which case it would be necessary to detach the wellpoint from the pipe 5 by uncrewing the coupling 4 therefrom, thus permitting the ring nut 24 and washer to be removed by upward displacement from the well-point, whereupon the pipe I9 with the channeled ribs 25 and screen 3 thereon may also be removed by upward displacement from the cage unit I.

In some instances it may be desired to make the coupling 4 a part of the cage'unit in which case the lower end of the coupling 4 could be welded or otherwise secured at 4 to the upper ends of the reamer bars 8 in addition to its screwing engagement with the nipple 6.

As previously stated, the inner pipe I9 is arranged in radially spaced relation to the tubular screcn'3 while the flange or valve seat 25 on the lower end thereof is of appreciably less diameter than the interior diameter of the lower pipe section I, thus forming an annular port 33 communicating with the channels in the ribs 23 and also with the spaces between said ribs, and also with the space below the inner pipe I9.

This port is controlled by the valve ring H which is preferably made of relatively soft rubber and is adapted to be closed against its seat 25 immediately upon the introduction of the jetting fluid downwardly through the inner pipe I9. That is, when the-water or other jetting fluid is introduced into the well-point from the top downwardly for jetting purposes, a part of the fluid will pass outwardly and upwardly through the port and into the channels of the ribs 23 .andspacesbetween said ribs due to the accumulation of water in' the bottom of the well, thereby producing more or less upwardsuction through the port 36 in addition to the upward lifting pressure of the trapped water in the lower end of the well-point with the result that the ring valve I'I will be automatically closed against its seat 25 to check the further upflow of the jetting fluid around the outside of the pipev I9.

Under these conditions, the ring valve II will be closed almost instantly upon the introduction of ajetting fluid through the well-point, thus directingthe entire force of the jetting fluid downwardly through the pipe I9 and ring 20 to the lower end of the well-point for loosening and displacing the underlying soil and allowing the wellpoint to descend into the soil under its own weight aided by occasional angular movement of the wellpoint about its axis to cause the teeth I2 to additionally loosen the underlying soil.

As soon as the valve I1 is closed against the seat 25, thereby closing the port 30, it will be held in its closed positionby the pressure of the jetting fluid from the bottom upward as long as the jetting operation continues.

When the well-point has been sunk to the required depth in the soil the-supply of the jetting fluid will be cut off through the operation of a suitable valve, not shown, thereby allowing the valve ring H to open under its own weight to rest upon the upper faces of the ribs I6.

The tubular cutting section II] is provided with a central port 32 some distance above the supporting member I5 for the float valve I4 and just below the horizontal plane of the tops of the ribs I6 to establish communication between the interior of the pipe I8 and valve chamber I3 when the float valve I4 is open and also to establish communication between the port 30 and valve chamber when the ring valve I! is open, said port being provided with a valve seat 33 in its lower end adapted to be engaged by the float valve I4 under conditions hereinafter described.

The supporting member I5 for the float valve I4 is preferably tubular and pivotally mounted upon the cross bolt or rivet I I to enable it to adjust itself to a position co-axial with the upper port 32 and is provided on its upper end with a valve seat I5 for the float valve I4.

This tubular member I5 is also provided with a plurality of, in this instance four, upwardly projecting guide posts 3! arranged in uniformly spaced relation about the axis thereof for guiding the valve I4 in its vertical movement and maintaining it in axial alinement with the lower valve seat I5 and upper valve seat 33 without in any way interfering with the free vertical movement of the valve, the upper ends of said guide posts 3! being flared outwardly against the walls of the valve chamber to prevent violent vibration of the valve under the action of the fluid during the jetting or suction operations, as experienced when the valve rests upon the pin I I alone.

The diameters of the ball valve and its supporting member I5 are considerably less than that of the valve chamber I3 to allow free passage of the jetting fluid from the pipe I9 through H the passages I6 and port 32 and thence through the section Ill to the bottom of the well-point for jetting purposes, it being understood that under these conditions the jetting fluid will be free to pass through the valve ring I'I when the latter is in position for closing the port 30.

It is now clear that the pipe I9, ring valve I1, and float valve I4 are arranged in co-axial relation and in sequence from the top downwardly and that the port 30 and lower end of the pipe I 9 are disposed in a horizontal plane between the ring valve H and top of the lower pipe section 1, thus permitting the ground water to flow from the outside between the cage bars 8 and through the screen 3 and thence downwardly through the channels of and spaces between the ribs 26 and port 30 into the valve chamber l3 when the ring valve i1 is open.

The accumulation of ground water in the bottom of the well and lower end of the well-point will automatically float the valve l4 against its seat 33, thereby closing communication between the valve chamber l3 and pipe I9 to prevent the upward passage of sand, small stones and other foreign matter from the bottom of the well into the pipe i9 and incidentally preventing the passage of said foreign matter to the suction pump with the ground water during the operation of withdrawing the ground-water from the well.

Operation The various parts of the well-point may be assembled in any suitable sequence. For example, the parts of the outer cage including the upper and lower tubular sections 6 and l and reinforcing rings 9 may be welded co-axially to the corresponding ends and intermediate portions of the lengthwise bar 8 to form a unitary structure.

The lower cutting section I with the valves l4 and I! thereon may then be inserted from the bottom upwardly into the lower pipe section 1 until its shoulder 10 is engaged with the lower end of said pipe section at which time the section 9 may be adjusted angularly to register its bolt openings with those in the pipe section 1 for receiving the bolt or rivet I l which latter may then be upset at both ends to hold it in place.

The cap section l8 with the pipe l9, channel ribs 28 and tubular screen 3 may then be assembled as a unit and inserted from the top downwardly through the upper ring 6 and reinforcing rings 9 until the flange on said cap section rests upon the upper end of the upper ring section 8 at which time the lower ends of the screen 3 and pipe l9 will project into the upper end of the lower pipe section I of the cage.

The gasket 22 is then placed in operative position between the upper reduced end of the cap section l8 and coupling member 4 and tightened in place by means of the washer 23 and nut 24 to seal the joint between the cap section l8 and upper ring 6 against the entrance of air or other fluid.

The coupling section 4 may then be screwed upon the upper ring sections 6 and connected to the lower end of the extension pipe 5 in the manner previously described.

When it is desired to sink the well-point into the ground, it, together with the pipe extension 5, is hoisted to an upright position with the lower end of the well-point resting upon the ground where it is to be sunk.

Water or other jetting fluid under pressure is then introduced into the pipe 5 from any available source and projected downwardly through the pipe l9, ring valve l1 and port 32 into the soil immediately adjacent the lower cutting edge of the section H) for jetting the soil away from the lower end of the well-point and allowing the latter to gradually sink into the ground to the required depth under its own weight aided by occasional turning movement thereof about its axis, thus constituting what may be termed the jetting operation.

At the beginning of this jetting operation, a portion of the jetting fluid under pressure will escape upwardly through the port between the lower end of the pipe l9 and upper end of the pipe section 1, thus producing an upward suction force in said port which, together with the water pressure trapped in the lower end of the wellpoint, closes the ring valve ll against its seat 25, thereby causing said valve to wedge tightly between the valve seat 25 and inner surface of the adjacent portion of the pipe I to stop the further upflow of the pressure liquid through the port, while the float valve l4 will be opened by the downward movement of the pressure fluid, thus directing the full force of the jetting fluid to the bottom of the well-point and consequently displacing the soil therefrom by erosion.

This jetting operation is continued until the well-point has been sunk to the required depth for draining the water from the surrounding soil at which time the supply of the jetting fluid will be cut off by a suitable valve, not shown, but provided therefor, thus allowing the ring valve IT to drop upon its supporting ribs l6.

Under these conditions, the jetting fluid or ground water accumulating in the lower end of the well-point will float the valve l4 against its seat 33, thereby cutting oir communication between the valve chamber 13 and pipe I9.

The ground water from the outside of the wellpoint will then flow between the bars 8 of the cage and through the screen 3 and thence downwardly through the lengthwise channels of and between the ribs 26 into the upper end of the pipe 1 and possibly into the valve chamber I3 until the valve i4 is floated to its seat 33.

The pipe 5 is then connected to a suction pump or equivalent device for withdrawing the ground Water from the interior of the upper end of the pipe 7 and upwardly from the lower end of and through the pipe H! to be discharged by the pump to any remote locality where it is prevented from seeping back to the well formed by the well-point.

This suction operation is continued until the water in the surrounding ground is completed or sufliciently drained to allow the sub-surface or super-surface work to begin.

When this withdrawal of the ground water is completed, the extension pipe 5 with the wellpoint thereon may be connected to any suitable hoisting device whereby it may be hoisted from the well preparatory to excavations for sub-structures or super-structures without liability of being impeded by the presence of ground water.

It is, of course, understood that several of these well-points may be simultaneously sunk into the ground in and around the water-containing area. to expedite the drainin of such area from ground water and that these several well-points may be connected alternately to one and the same source of fluid pressure supply or to one and the same suction pump without departing from the spirit of the invention.

During this suction operation of withdrawing the ground water from the interior of the wellpoint and from the surrounding ground, the float valve M will, of course, be drawn to its closed position against the seat 33 partly by suction and partly by the water which may be trapped in the botton of the well, but in either event it will be positively closed so that the entire suction force may be exerted in withdrawing the ground water from the outside inwardly and upwardly through the pipe I9 and discharged to some remote position by the suction pump or equivalent device.

What I claim is:

1. A well-point adapted to be sunk into watercontaining soil for withdrawing the water therefrom comprising an inner pipe, a tubular screen surrounding the pipe in radially spaced relation thereto, and a cage unit surrounding the screen in radially spaced relation thereto and having its lower end provided with a tubular head extended below the inner pipe in spaced relation thereto to form a port to allow the ground-water to pass therethrough and through the screen into the lower end of the cage unit, and. a ring-valve controlling said port.

2. A well-point adapted to be sunk into watercontaining soil for withdrawing the water therefrom comprising an inner pipe, a tubular screen surrounding the pipe in radially spaced relation thereto, and a cage-unit having axially spaced lower and upper end heads and lengthwise bars connecting said heads and spaced circumierentially and radially relatively to the outer periphery of the screen, the lower head being extended above the lower end of the inner pipe in spaced relation thereto to form a port, and a ring-valve co-axial with said pipe and controlling said port.

3. A well-point adapted to be sunk into watercontaining soil for withdrawing the water therefrom comprising an inner pipe, a tubular screen surrounding the pipe in radially spaced relation thereto, and a cage-unit having lengthwise bars spaced circumferentially and radially relatively to the outer periphery of the screen, said cage being adapted to be turned about its axis and having the intermediate portion of its bars bowed outwardly and angular in cross section for reaming the walls of the well during the turning movement of the cage.

4. In a well-point of the character described, an outer cage having a series of lengthwise bars arranged in uniformly spaced relation about a common axis, tubular heads secured to opposite ends of the bars, the intermediate portions of the bars between the heads being bowed outwardly, and a pipe extending lengthwise of and within the cage and adapted to be connected to a source of fluid supply for jetting the soil away from the lower end of the well-point.

5. In a well-point of the character described, an outer cage having a series oi lengthwise bars arranged in uniformly spaced relation about a common axis, lower and upper tubular members secured to opposite ends of the bars, and a pipe extending lengthwise of and within the cage below the upper end of the lower tubular member in radially spaced relation thereto to form a port and adapted to be connected to a suction device for withdrawing the ground-water from the interior of the cage, and a ring-valve controlling said port.

6. In a well-point of the character described, an outer cage comprising co-axial tubular members arranged in axially spaced relation, and a series of lengthwise bars arranged in circumferentially spaced relation. about the axis of said members and having their opposite ends rigidly secured to the corresponding members and their intermediate portions bowed outwardly, and means for holding said intermediate portions in their outwardly bowed positions, in combination with a pipe extending lengthwise of and within said members co-axial therewith and adapted to be connected to a suction device for withdrawing the groundwater from within the cage.

7. In a well-point of the character described, an outer cage comprising -co-axia1 tubular members arranged in axially spaced relation, and a series of lengthwise bars arranged in circumferentially spaced relation about the axis of said members and having their opposite ends rigidly secured to the corresponding members, in combination with a pipe extending into and below the upper end of the lower member in radially spaced relation. thereto to form a port and adapted to be connected to a source of fluid supply under pressure for jetting the soil away from the lower end of the cage, and a ringvalve controlling said port.

8. In a Well-point of the character described, an outer cage having co-axial tubular members arranged in axially spaced relation, in combination with a jetting and suction pipe extending lengthwise of and within said members coaxial therewith, the lower tubular member having a co-axial v port in a plane below the lower end of said pipe, a self-opening valve within said lower tubular member adapted to be closed by suction in said pipe, and a pivoted support for said valve when the latter is in its open position for steadying the valve against violent agitation during the jetting operation.

9. In a well-point of the character described, an outer cage having lower and upper coaxial tubular members arranged in axially spaced relation, in combination with a jetting and suction pipe extending lengthwise of and within said members -co-axial therewith, the lower member having a port below said pipe, a selfopening float-valve Within the lower tubular member controlling said port, and a tubular support for said valve when the latter is in its open position.

10. In a well-point of the character described, an outer cage unit having lower and upper tubular members arranged in axially spaced coaxial relation, in combination-with, a pipe extending into the upper end of the lower member in radially spaced relation thereto to form a port to allow the ground-water to pass from the outside through the cage and into the lower tubular member of the cage, and a ring-valve co-axi a1 with and below said pipe for controlling said port.

11. In a we l-point of the character described, an outer cage unit having lower and upper tubular members arranged in axially spaced coaxial relation in combination with a pipe extending into the upper end of the lower member in radially spaced relation thereto to form a port to allow the ground water to pass from the outside through the cage and into the lower tubular member of the cage, and a ring-valve supported within the lower tubular member of the cage and adapted to be actuated by the passage of fluid through the pipe for closing the space between the lower end of the pipe and lower tubular member.

12. In a well-point of the character described, an inner pipe, a cage surrounding the pipe in radially spaced relation thereto and having its lower end provided with a tubular member extending some distance below said pipe, the upper end of said tubular member and lower end of the pipe being spaced radially to form a port through which the ground water may pass from the outside into said member, and a check valve operated by the passage of fluid through the pipe for closing said port, the check valve being made in the form of-a ring co-axial with the pipe to allow the fluid to pass therethrough.

13. In a well-point of the character described, axially spaced co-axial lower and upper tubular heads, a tubular screen having its lower and upper ends engaging the corresponding heads, a tubular cap inserted in the upper end of the screen, a cylindrical pipe secured to said cap to extend downwardly therefrom within and below the upper end of the lower head in radially spaced co-axial relation thereto and to the screen to form an intervening water passage, and channel bars of U-shaped cross section extending lengthwise of and within said passage in engagement with the screen and pipe to hold those parts in concentric relation.

14. In a well-point of the character described, axially spaced co-axial lower and upper tubular heads, a tubular screen having its lower and upper ends engaging the corresponding heads, a tubular cap inserted in the upper end of the screen, a cylindrical pipe secured to said cap to extend downwardly therefrom within and below the upper end of the lower head in radially spaced co-axial relation thereto and to the screen to form an intervening water passage, channel bars of U-shaped cross section extending lengthwise of and within said passage in engagement with the screen and pipe to hold those parts in concentric relation, and a ring-valve controlling communication between said passage and the interior of the lower end head.

15. In a well-point of the character described, axially spaced co-axial lower and upper tubular heads, a tubular screen having its lower and upper ends engaging the corresponding heads, a tubular cap insert in the upper end of the screen, a cylindrical pipe secured to said cap to extend downwardly therefrom within and below the upper end of the lower head in radially spaced coaxial relation thereto and to the screen to form an intervening water passage, channel bars of U-shaped cross section extending lengthwise of and within said passage in engagement with the screen and pipe to hold those parts in concentric relation, the lower head being provided with coaxial valve chambers connected through a port, a float-valve controlling said port, and a ring-valve controlling communication between said port and said passage.

16. In a well-point, axially spaced co-axial tubular heads, a foraminous tubular member connecting said heads in fixed co-axial relation thereto, a jetting-and-suction pipe connecting the heads co-axial therewith within said member and combining with the latter to form a drainage space normally in open communication with the interior of said pipe through the lower end thereof to allow the drainage water to be drawn from said space into the pipe during the suction operation, and means actuated by the passage of a jetting fiuid through said pipe for cutting oif said communication and thereby to prevent the escape of the jetting fluid through said space.

17. In a well-point, axially spaced co-axial tubular heads, a foraminous tubular member connecting said heads in fixed co-axial relation thereto, a jetting-and-suction pipe connecting the heads co-axial therewith within said member and combining with the latter to form a drainage space normally in open communication with the interior of said pipe through the lower end thereof to allow the drainage water to be drawn from said space into the pipe during the suction operation, and a ring-valve co-axial with said pipe and adapted to be actuated by the passage of the jetting fiuid therethrough for cutting off said communication.

18. A well-point having a lower tubular end head and a jetting pipe discharging into the upper end thereof, in combination with a foraminous tubular member extending upwardly from said head around the pipe and combined therewith to form a drainage space in normally open communication with the lower end of the pipe, and a ring-valve adapted to be operated by the jetting fiuid passing through said pipe for cutting off said communication and allowing the jetting fluid to pass through the valve.

19. In a well-point, the combination with an outer tubular shell having a relatively fixed tubular filtering screen through which the drainage water from the soil is adapted to pass, and an inner jetting-and-suction pipe in fixed co-axial relation to and combining with the outer shell to form a drainage chamber, said pipe and chamber being normally in open communication with each other to allow the drainage water to be withdrawn from the chamber through the pipe by suction, and means co-axial with said pipe and actuated by the passage of jetting fluid through said pipe for cutting oif said communication without obstructing the passage of the jetting fluid through the pipe.

THOMAS F. MOORE.