US3638726A

US3638726A - Well screens

Info

Publication number: US3638726A
Application number: US874315A
Authority: US
Inventors: David L Sibley
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-11-05
Filing date: 1969-11-05
Publication date: 1972-02-01
Anticipated expiration: 1989-02-01

Abstract

The well screen has an outer tube and a telescoping inner tube. The tubes have identical horizontal series of slots therein. The outer tube is initially adjusted longitudinally with respect to the outer tube to gauge the slot openings through the communicating slots of the tubes. Solvent cement is used for securing the tubes in adjusted position.

Description

W 0 United tates ateitt 1151 3,638,726

Sibley 1 lFeb. 1, 1972 [54] WELL SCREENS 1,594,788 8/1926 McLaughlin et al ..l66/236 X 1,861,722 6/1932 Searle ..l66/236 [721 wmdwy Lane 2,681,111 6/1954 Thompson ...l66/236 x Paagmld, 72450 2,973,814 3/1961 Adams et a1. ..l66/236 x 22 i N 5 19 9 3,502,145 3/1970 DuMee et a1. ..166/236 X PP 874,315 Primary Examiner-Stephen J. Novosad Attorney-Alexander & Dowell [52] 11.8. C! ..ll66/236 AB '1 [51] ....E031) 3/20, E21b 43/08 [57] STRAC [58] Field 01 Search ..166/236, 227,205,513 The well screen has an outer tube and a telescoping inner tube. The tubes have identical horizontal series of slots 5 References Cited therein. The outer tube is initially adjusted longitudinally with respect to the outer tube to gauge the slot openings through UNITED STATES PATENTS the communicating slots of the tubes. Solvent cement is used for securing the tubes in adjusted position. 419,606 1/1890 Jewell ..166/236 UX 1,500,828 7/ 1924 Layne 1 66/236 4 Claims, 5 Drawing Figures Io w PATENIEBFEB mm 353 7 TTOR N EYS WELL SCREENS DESCRIPTION OF INVENTION This invention is a novel well screen for use in the procurement of underground water at well sites, and the principal object of the invention is to provide a well screen consisting of inner and outer plastic tubes each having identical horizontal series of slots therearound, the series in one tube being slightly offset from those of the other, and the tubes being initially relatively adjusted longitudinally to gauge the slot openings through communicating slots, after which the tubes are welded together by solvent cement.

Another object of the invention is to provide a well screen of the above type in which the gauging of the slots between the inner and outer tubes may be effected at the well site, the solvent cement being applied to weld the inner and outer tubes together before insertion of the well screen into the well.

Heretofore well screens have been provided using only one tube rather than inner and outer tubes, said tube being provided with horizontal slots of the thickness of the saws, i.e., about 0.008 in., but it has been found that there is a need for well screens having a finer slot than 0.008 in. The saws making slots of substantially 0.008-in. thickness are so thin that their use becomes expensive because of frequent breaks and necessary frequent sharpening of the saws. But I have provided a well screen in which circular gang saws of thickness greater than 0.008 in. may be used, thereby eliminating the problem of slot thickness in a single tube, since by adjustment of the slots in the inner tube with those of the outer tube the effective slot thickness can be reduced to approximately 0.0001 in.; also the offset lips of the slot provide high superiority in that they are nonclogging and economical; and just before the slots are properly gauged the contacting surface of the inner and outer tubes are coated with a solvent cement, thus closing all openings therein except the gauged slots which are left open for screening purposes.

Other minor objects of the invention will be hereinafter set forth.

I will explain the invention with reference to the accompanying drawing which illustrates one practical embodiment thereof to enable others familiar with the art to adopt and use the same; and will summarize in the claims the novel features of construction, and novel combinations of parts, for which protection is desired.

In said drawing:

FIG. 1 is a perspective elevational view of a section of my novel well screen showing the arrangement of slots in the inner and outer tubes.

FIG. 2 is an enlarged transverse section on the line 22, FIG. 1.

FIG. 3 is a vertical section through the assembly shown in FIG. 1.

FIG. 4 is an enlarged detailed view illustrau'ng the gauging of the slots in the inner and outer tubes.

FIG. 5 is a perspective view, partly in section, showing gauged slots.

As shown in FIG. 1, my novel well screen comprises an outer tube 1 and a telescopically arranged inner tube 2 of desired diameter, each having aligned rows of horizontal slots 1a, 2a, therein, five such rows being shown in FlG. 2 equally spaced around the periphery of the tubes, with the slots 2a of the inner tube 2 being disposed substantially directly behind the slots 1a of the outer tube 1. The slots la and 2a may preferably be formed in the tubes 1 and 2 by means of a circular gang saw in which the saws are equally spaced apart and are of equal thickness so that the slots 1a, 2a are substantially identical in both the inner and outer tubes. Preferably the assembly of inner and outer tubes would be delivered to the well site, and before gauging of the opening between adjacent slots lla, 2a, as shown in FIGS. 4 and 5, the inner surface of the outer tube 1 and the outer surface of the inner tube 2 would be coated with a suitable solvent cement. The inner tube 2 would then be adjusted within the outer tube 1 to rovide the desired gauge, indicated at X, FIG. 4, by ad usting e tops of the slots 24; to the desired gauged position above the bottoms of the communicating slots la, as shown in FIG. 4, so that when the solvent cement acts and sets the slots 2a in the inner tube 2 and slots 1:: in the outer tube 1 are gauged the correct distance for the desired screening purpose, which distance X may, as above stated, be in the vicinity of 0.0001 in. up to 0.008 in. or

more.

After the solvent cement has acted and set the tubes will be permanently secured together, having the desired gauge X, and the cement will close all openings in the tubes except the gauged slots X which are left for screening purposes.

My well screen thus provides the industry with a screen that will have openings X which are finer or narrower than the present screens available on the market. The industry needs a well screen using plastic tubes which provide a gauge slot X finer than 0.008 in. This cannot be accomplished using the expensive saws now on the market which are so thin that the saw has frequent breakage and requires frequent sharpening. The industry needs economical screening slots down to 0.005 in. to screen out small articles. My well screen eliminates this problem and provides a slot which can be closed to 0.0001 in. and the offsetting lips of the slots provide a high superior nonclogging screen involving simplicity and economy. Moreover, my well screen can be assembled and gauged at the well site to suit the actual conditions prevailing at such site. The use of the solvent cement between the inner and outer tubes closes all openings in the tubes except the gauged slots X which are left for screening purposes.

I claim:

l. A well screen comprising an outer tube, a telescoping inner tube, said tubes having identical horizontal series of slots therein formed such that the series of slots in said inner tube are capable of registering with the corresponding series of slots in the outer tube, the inner tube being adjusted longitudinally with respect to the outer tube to gauge the slot openings through the communicating slots of the tubes; and means for securing the tubes in adjusted position comprising solvent cement applied to the contacting faces of the said tubes prior to adjustment of the tubes, the cement when set closing all openings in the tubes except the gauged slots.

2. In a well screen as set forth in claim I, said tubes being of plastic material, and the series of slots being arranged in vertical rows substantially evenly spaced around the periphery of the tubes, with the rows in the inner tube disposed directly behind those of the outer tube.

3. In a well screen as set forth in claim 1, the gauged slots being defined by the spaces between the tops of the slots in the outer tube and the bottoms of the slots in the inner tube.

4. In a well screen as set forth in claim 3, said tops and bottoms of the slots forming offset lips preventing clogging of the gauged slots.

Claims

1. A well screen comprising an outer tube, a telescoping inner tube, said tubes having identical horizontal series of slots therein formed such that the series of slots in said inner tube are capable of registering with the corresponding series of slots in the outer tube, the inner tube being adjusted longitudinally with respect to the outer tube to gauge the slot openings through the communicating slots of the tubes; and means for securing the tubes in adjusted position comprising solvent cement applied to the contacting faces of the said tubes prior to adjustment of the tubes, the cement when set closing all openings in the tubes except the gauged slots.

2. In a well screen as set forth in claim 1, said tubes being of plastic material, and the series of slots being arranged in vertical rows substantially evenly spaced around the periphery of the tubes, with the rows in the inner tube disposed directly behind those of the outer tube.