US2682309A

US2682309A - Well screen structure

Info

Publication number: US2682309A
Application number: US298810A
Authority: US
Inventors: William J Banchback
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-07-14
Filing date: 1952-07-14
Publication date: 1954-06-29
Anticipated expiration: 1971-06-29

Description

June 29, 1954 w. J. BANcHBAcK WELL SCREEN STRUCTURE Filed July 14, 1952 a 3 3 u R 2 z 0, R f f f 9 9 9 l N V EN TOR. I/z'lliam J azzaaat Patented June 29, 1954 UNITED STATES PATENT OFFICE 6 Claims.

The present invention relates to well screens and comparable devices such as drive well points and has for an object the provision of devices of this kind that are exceptionally strong and eiTcient, and of a method whereby they can be made at a reasonable cost.

Another object oi the invention is to provide a structure of this kind including longitudinal bars and a helical winding of keystone wire secured thereto in a manner which provides for mutual mechanical interlock and mutual reinforcement of the parts so that accuracy of flow slot size may be maintained under adverse handling conditions.

A further object of the invention is to provide a method of forming devices of this kind wherein the base of the keystone wire is bent laterally in slots in the bars thereby strengthening the winding and simultaneously effecting the interlocking thereof with the bars.

A still further object of the invention is to provide a device of this kind with a maximum length of accurate and continuous flow slot to afford eiciency in operation.

These and other objects are provided by the means and method described herein and exemplified in the accompanying drawings in which:

Fig. 1 is a side elevational view of a Well screen embodying the invention, part being broken away.

Fig. 2 is a cross sectional view taken on line 2-2 of Fig. 1.

Fig. 3 is a cross sectional view taken on line 3-3 of Fig. 1 and illustrating the successive steps in the construction of the device.

In the manufacture of well screens and the like various arrangements have been used or suggested in attempts to secure, at reasonable cost, a structure that is strong and eicient but all of these have left much to be desired. The practice of welding the Winding and bars together and the practice of caulking the metal of the bars and/or winding have both presented diiiiculties of one sort of another.

According to the means and method of the present invention I employ a keystone type winding wire 5 of a special shape in which the base or web 6 is much higher than the keystone head 'I and secure the turns of such wire 5 in specially formed angularly turned slots 8 formed in the bars 9 of the screen structure as exemplified herein and indicated generally at III. The bars 9 are wide and may be relatively thin and these are initially arranged to be held edgewise in radial relation to the center axis of the well screen to outline a cylinder about which the keystone head 'I of the wire is arranged in accurately spaced turns to provide a continuous and uninterrupted selfcleaning flow slot I I.

The simple, strong and mutually reeniorcing structural connection which eliminates previous diiliculties in well screen construction consists in forming in each bar 9, where the winding intersects it, a slot 8 which extends perpendicular to the outer edge face I2 of the bar and then has an angularly turned extension I3. Into each angle slot 8I3 the entire base or web 6 of the keystone Wire is tted, leaving the head or keystone portion of the wire to form a helix of spaced turns extending outside the outer edge faces I2 of the bars so that the inwardly divergent slot II is continuous and uninterrupted.

As can be best understood from an inspection of Figs. 1 and 3 any desired number of bars 9, sufcient to support the required Winding to provide a predetermined flow space II, may be employed. Said bars 9 are arranged edgewise radially of a common center axis and in longitudinal parallelism to form the outline cf a cylinder. Any suitable mandrel (not shown) may be used for holding the bars in position during construction oi the well screen, and an end coupling member I4 is applied to the bars 9 by threaded and/or brazed connection at I5. The bars 9 are by preference initially unslotted and the bar slots 8--I3 are formed successively in adjacent bars along the path of a helix while the base of the winding wire is entered and then turned laterally to conform to the cross section of the slot in the bar.

As will be best understood from an inspection of Fig. 3, if the size of the well screen and the size of its flow slot be such that a relatively thicker keystone wire is indicated, then it is desirable that a longitudinal groove I6 be cut along the side face of the wire base 6 to assure bending of the base 6 along the line of said groove as the base is forced into the angle slot in the bar.

The Wire 5 has its base guidedly fed into the vertical portion 8 of the slot whereupon any suitable pressure means, e. g. a roller indicated in dashed lines at I'I forces the leading edge of the base 6 into the angularly related portion I3 of the slot until the slot 8-I3 is completely iilled with the base` Ii and the keystone head 'I of the wire extends from the outer edge of the bar. The act of laterally bending the wire to conformity with the cross section of the slot 8-I3 eiects a work hardening of the wire which cooperates to further strengthen the helical winding while the laterally turned longitudinal bend is progressively formed in the wire.

A strong positive interlocking binding of the wire at each slot in each of the bars is thus effected. The overall structure of a well screen (or a drive well point) thus formed is strong and rigid and it resists distortion under any and all kinds of strains and stresses that may be imposed on it. The metal of the bars is not weakened by caulking of its metal as in some known forms of `well screens. Instead the winding and the bars mutually reenforce each other. The overall weight of materials may be appreciably less than in known screens intended and designed for identical duty.

When the strainer structure is of small diameter and the ow slot ll is very narrow, a keystone wire therein indicated may have its web thin enough to be bent without the use of a groove such as I6.

The lmethod of speedily making well screens according to the invention consists essentially in supporting the bars 9 to outline a cylinder, progressively cutting the angle yslots 8-13 along the path of a helix o'f desired lead, guidedly entering the base of the keystone wire to the full depth of the vertical slot portion 8 in the bar and finally exerting force on the top of the keystone head of the wire to cause the base of the wire to bend laterally into conformity and mutually interlocking relation with the angle slot 8-l 3. The angle slot 8-83 may be formed in various ways by means forming no part of the present invention.

What is claimed is:

1. A well screen device comprising a plurality of thin wide support bars arranged radially edge- Wise about a common center axis, said bars having angle slots in -spaced relation and disposed along a helical path about the plurality of bars, the slots being parallel sided and each slot entering perpendicularly into the edge of the bar for a distance and then turning obliquely toward one end of the bar, and a keystone Wire having a parallel sided base entered fully in and laterally bent along its length into conforming relation to each slot and disposing the keystone head thereof outwardly of the outer edges of said bars.

2. In a device of the class described the combination of a plurality of thin wide bars arranged edgewise radially about a common center axis, the bars having slots extending from the outer edges thereof perpendicularly for a distance and then angularly inclined toward a common end of the bars, and a keystone wire'including a base fitting snugly into the perpendicular and angularly inclined portions of the slot to form a mechanical interlock of the `wire base in each of said slots and to provide a longitudinal reenforcing bend in the wire.

3. In well screen the combination of parallel bars arrange-d to outline a cylinder and successively slotted to define a helical path passing through the outer portions of the bars, the slots each extending radially inwardly from the outermost portions of the bars and thence inclined toward a common end of said bars to present an angular cross section shape, and a keystone wire having a keystone shaped head located beyond the open end of the slot and a base having a longitudinal extending reenforcing bend conforming to the cross section of said base to the cross section of each groove and forming an interlocking permanent connection of the base of the wire within each Slot in each bar.

4. The method of making a Well screen which comprises the steps of disposing a plurality of bars in parallelism in the outline of a cylinder, progressively cutting angle slots in successive bars to dene a helical path in the plurality of bars, said slots extending from the outer edge of the bar perpendicularly for a `distance and then inclined angularly toward a common end of the bar, entering the base of a keystone wire into the open top of each slot on completion of the cutting thereof and forthwith subjecting the head of the keystone wire to pressure and causing the base of the wire to bend laterally into completely filling and interlocking relation with the sides of the angle slot.

5. The method of making well screens and the like which comprises the steps of form-ing a shallow longitudinal groove in one side wall of the base of a keystone wire, arranging a plurality of bars in the outline of a cylinder, progressively forming angle slots in successive bars along a helical path, said angle slots being parallel sided and entering perpendicularly from the outer edge of the bar for a distance and then inclined angularly toward an end of the bar, feeding the base of the wire into the open tops of said slots successively and forthwith forcing the base of the wire into the successive slots for forming a work hardened reenforcing bend extending longitudinally ci the wire from said groove to the vend of the base as said end of the base enters and iills the angle slots whereby an interlocking mechaniconnection is completed between the wire base and the bars at each slot in-said bars.

6. The method of making well screens .and .the like comprising the steps-of longitudinally grooving a key-stone wire along one face of .the base thereof, supporting a plurality -of bars` radially edgewise in the form Aof the -outline of a cylinder, progressively forming parallel sided :angle yslots in successive bars along a helical path about ysaid plurality of bars, the :angle slots each including a top portion extending vfrom the outer Vedge of the bar perpendicular thereto fora distance equal to substantially the distance between the .keystone head of the wire and the groove in the base thereof, said slot extending ang-ularly from Vsaid top portion toward the end of the bar, the tota-l cross sectional area 'of lthe wire base being substantially equal .to the cross sectional area of the slot, and successively forcing the base of 4thefkeystone wire into the successive yslots While winding the wire about the bars for laterally bending the base of the wire to conform the Ishape thereof `to the shape of the slot, said bending operation at. least partially closing the groove in the side y0.1i the wire base.

yReferences Cited in the le 'of this patent UNITED STATES PATENTS Number Name Date 691,994 1Webber Jan. 28, 1992 857,313 Stancliff June 18, 1907 856,559 Basye Sept. lTI, 19057 1,858,592 Johnson May 17, 1932 2,160,790 Swanson May 30, 1939