US1165137A - Double-walled strainer for culverts, drainage-casings, &c., and connecting means therefor. - Google Patents

Description

A. SMITH.

DQUBLE WALLED STRAINER FOR CULVERTS, DRAINAGE CASINGS, 610., AND CONNECTING MEANS THEREFOR.

APPLICATJION FILED JULY 29, 1913.

1,165,137, I Patented Dec. 21, 1915.

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DOUBLE WALLED STRAINER FOR CULVERTS, DRAINAGE CASINGS, &c., AND CONNECTING MEANS THEREFOR.

APPLICATION FILED JULY 29, 1913.

1,165,137. Patented Dec. 21, 1915.

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DOUBLE WALLED STRAINER FOR CULVERTS, DRAINAGE CASINGS, 810., AND CONNECTING MEANS THEREFOR.

APPLICATION FILED JULY 29, 1913.

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' APPLICATION FILED JULY 29. 1913.

Patented Dec. 21, 1915.

5 SHEETS-SHEET 5 UNITED STATES PATENT OFFICE.

ANDREW SMITH, OF SAN MATEO, CALIFORNIA.

DOUBLE-WALLED STRAINER FOR CULVERTS, DRAINAGE-CASINGS, 850., AND

CONNECTING MEANS THEREFOR.

To all "whom it may concern:

Be it known that L-ANDREW SMITH, a citizen of the United States, residing at San Mateo, in the county of San Mateo and State of, California, have invented certain new and useful Improvements-in Double-\Valled Strainers for Culverts, Drainage-Casings, &c., and Connecting Means Therefor, of which the following is a specification.

This invention relates to perforated casings for use in culverts, drainctiles, wellstrainers, or curbing, etc., andits' object is to provide a casing section-having airintegral, intermediate duplex draining -or strainer portion.

A further object is to. provide acasing section. having an intermediate doublewalled draining portion and single-walled terminal end portions which may be connected by threaded union members or otherv connecting means with the ordinary culvert, well, or other drainage casings.

It is frequently desirable to introduce draining sections into a line of culvert pipe or well casing. \Vhile such drainage section may comprise a single-walled perforated or slitted pipe, yet I have found that a double-walled casing is much more effective in securing an increased drainage capacity and is less liable to become clogged by the surrounding earth, sand and gravel. Vhen a casing is drilled with holes or otherwise perforated, the metal walls are necessarily much weakened but by my invention the perforated inner casing is strengthened by the outer perforated strainer portion which is welded or riveted to the inner casing 'so that the whole becomes an integralunit.

I The perforations-are confined .to .the. doublewalled portion, the single-walled ends'being imperforate.

The structural feature of my invention and-the advantages which are derived from its use will be understood from the follow ing description in connection with the accompanying drawings, in which Figure 1is an elevation of a casing partly in section, embodying my invention; Fig. 2 is anelevation of a casing showing one of my preferred forms of threaded connections; Figs. 3 to 28, inclusive, illustrate various embodiments of my invention.

Referring to Fig. 1, th casing section .of the punched metal parts.

Specification of Letters Patent. Patented Dec, 21, 1915, Appllcatlo i filed July 29, 1913. Serial No. 781,820.

comprises a main casing member 2, which I have illustrated as having threaded terminal portlons to receive ordinary coupling unions 3, and an intermediate portion provided with perforations which may be in the form of holes'drilled or punched or sheared there- 1n. The outer member '7 of the duplex drainage portion which is slid over the perforated portion of the main casing is prefer- I ably asingle tube but I may form it .of two similar parts which abut at the center, the

abutting flanges 9 beingwelded together, or,

parts may be riveted together to make an integral structure, as shown at 10, Fig. 3, but it is far preferable to weld them.

The outer element or member 7 is provided with narrow sheared slits to form a screen or strainer. In the shutter-like forms shown in Figs. 1, 6, 12, 14 and 22, the slits are bounded by the inner edges of the outer lips and the outer edges of the inner lips 14 The slits are preferably first formed in the sheet metal, from which the casing is constructed, by shearing the metal in the manner disclosed in my prior Patents Nos. 1,027,917, 1,028,066 or 1,055,615. The slits formed in accordance with the processes of my said prior patents are practically smooth-walled and may be thoroughly protected from corrosion by galvanizing, sherardizing or other coating process, and the width of the slits may be made as narrow as desired. depending upon the character of the formations in which the drain casing is to be embedded.

The sheared sheets are bent into tubular form and welded at the seam or joint to form tubular sections, but it is obvious that the narrow slots may be formed by perforating the casing. I prefer to form the outer member, or slip-over portion, of' each cas-.

ing section of a continuous length of sheared tube or pipe, making it necessary only to weld the ends 8 to the main casing.

.use larger apertures in the inner wall.

The elongated narrow slits in the outer- .13, .15, 19 and 23, the inner edges of the inturnedlips 14, may be constructed to bear against the inner. casing and maintain the inner and outer" walls spaced .apart sufliciently to insure a 'free unobstructed passage of the water oroil entering through v outer strainer casing or screen.

The main casing 2 is constructed from heavy sheet metal and can be made of noncorrosive material. The outer slip-over member 7, which is provided with practically smooth-walled shearedslits, isusually of thinner sheet metal and may be made of brass, copper or other non-corrosive metal,

or other metals may be used and galvanized or otherwise coated to protect from corrosion. The casing sections or units may be threaded upon either end in the usual manner with the threads either cut or rolled into the metal, as illustrated at 2 in Fig. 1, and be connected by means of threaded unions or coupling rings 3. In this form of coupling in which; the threads are cut into the metal, the walls of the pipe are weakened and the strength of the joint depends upon the comparatively shallow threads. The strength of such couplings is not over per cent. of the strength of the casing at other points.

In order to provide ameans for handling the sectional units without injury to the perforated portions, when they are being laid in an open ditch or being'forced through a tunnel in constructing a culvert or when belng lowered by elevators into the bore of 'a well, I leave a plain portion 2 between the duplex strainer portion and the corrugated or threaded end portion. The outer 'caslng member is preferably formed with plain end portions 8 for a distance of a few inches to provide reinforced plain portions,

At these plain pipe portions. the tongs, clamps'or elevators may be attached. The spiral corrugations or threads at the ends are always formed so that the sections will be turned *in a right-hand or clock-wise di-.

rection, in order that none of the sections may become disconnected. For this reason I arrange the lipsof the perforations in the arrangements shown in Figs. 1, 12, 14 and 23, so that they extend in a left-hand direction and when the casing is rotated in a right-hand direction the perforations will not be'comeclogged with earth, as would evidently be the case if they pointed in the opposite direction.

As previously stated, the outer slitted portion forms a strainer and also a reinforcement for the inner perforated member. The slits in the outer member 7, are made'to allow the very fine particles of earth to flow side of each shear cut may be forced inwardly as shown in- Figs. 12, 13, 18 and 19; or opposite sides of the cut may be forced in opposite directions as in Figs. 14 and 15. Under some conditions it maybe desired to have a perfectly" smooth exterior and the slits maybe formed by spreading the metal upon either side of a'row of slits as inFig. 3. The process of forming these slits is disclosed in my Patents Nos. 1,027,917 and 1,028,066, dated May 28, 1912 and No.

1,055,675 dated March 11, 1913. The slits are preferably \l-shaped in cross-section, with the narrower side outward so that the ing is to be subjected. The metal upon one slit will gradually increase in width from the outer to the inner side ofthe casing as shown in the outer casing in Figs. 17 and 21. With this construction the slits are not liable to become'clogged since any small particles of sand that pass into the slit will immediately pass into a larger opening and cannot wedge or bind between the sides of the slit.

Another method of forming slits is by forcing alternate strips of metal between the slits inwardly as shown at 16 in Figs. 1 and 5. In this construction the slits are formed between the edges of the forced-in strips 16? of the casing, which also serve to stiffen the casing. It is obvious that the perforated casing may be formed by bending the sheet 'in the reverse direction so that the sheared strips which have. been forced slightly out of the plane of the sheet will extend outwardly of the'casing. The slits may also be formed by forcing adjacent alternate strips inopposite directions', as indicated in Figs. 10 and 11. The parallel slits 17, thus formed may be made as narrow as desired for straining purposes,

as it is only necessary for the metal strips to be forced to one side slightly morethan halfthe thickness of the metal. This construction forms an exceedingly efiicient fully disclosedin myPatent No. 1,057,098

dated March 25, 1913. This form of slitted casing increases the draining capacity without decreasing the strength of the casing.

I have shown the slitted strainer member placed upon the outside of the inner casing which extends beyond ,the strainer member at the ends, but under some conditions the strainer member may be placed inside of the main casing member and become the inner part of the double-walled intermediate portion as illustrated in Fig. 26, and this arrangement is included within the scope of my claims. The casing may be made more rigid by means of corrugations 20 between the series of slits, which may extend circumferentially as in Figs. 12 and 16, or spirally as in Fig. 8/ It will be observed that the corrugations bear against the inner pipe and maintain the outer slitted "member spaced away from the inner member, thereby insuring an unobstructed passage for the water from the outside to the inside of the casing. The slits may extend into the corrugations in order to provide a passage for the fluids to flow around any obstructions that may be against the strainer.

\Vhile it is preferable that the slits should extend longitudinally "of the casing since this construction offers less resistance as.

the casing is. being forced into the bore of the earth during the construction of a culvert, draining .tunnel or well, 'yet under some conditions it-may be desirable to ar-. range the slots horizontally in longitudinal series as illustrated in Figs. 6 and 18. It is evident that instead of punching the holes in the inner casing, I may perforate it with sheared slits in the same manner as the outer member is slitted. The lips adjacent the slits in the outer member may be pressed inwardly and those in the inner casin'gmay be pressed outwardly. and the longitudinal I series of the inner and outer casing members mav alternate or interfit with each other in staggered relation, as illustrated in Fig.28. It isto be understood, therefore, that my claims cover constructions in which the outer and inner casing members are both provided with sheared slits. or either may be provided with sheared slits and the other with punched holes. Furthermore, it is to become clogged with evident that this arrangement of slitted or slitted and punched members may be applied to casings which are double-walled throughout their extent. The slits may also be arranged in other ways, as for instance, 1n sp1ral series as shown in Fig. 22. The

corresponding cross-sectional views adjacent each side elevation will make the construc-' tions clear.

I have referred to the single-walled end portions as being imperforate yet there may be conditions in which it is desirable to also provide 1 perforations in the end portions and it is to beunderstood. that such con structions come within the scope of my broader claims. I also regard as within the purview of my invention claimed herein, a construction in which the ends of the outer slip-over strainer member are extended as far as the connecting collars or .otherconcorrugations which I have described in connection with Figs. 10 and'20, may be applied to an imperforate pipe, conduit, drain tile, culvert or well casinghaving either plain or corrugated walls, or to a single-walled perforated casing. In Fig. 2, I have illustrated my reinforced spirally corrugated end connection applied to a single-walled culvert or well strainer casing provided with my shutter-like sheared slits.

I have described in detail the various modifications shown in the figures. of the accompanying-drawings for the purpose of illustrating specific embodiments of my invention, but it is evident that various changes may be made therein without departing from the spirit of my invention. I have shown in the various drawings anouter strainer member having narrow sheared slots therein but it is obvious that this strainer member may be used as an inner section.

The advantages to be derived from the use of my invention disclosed herein in' which each. sectional unit is an inte a1 structure and in which the intermedlate strainer portion comprises duplex walls which mutually reinforce each other, while the whole presents a comparatively smooth unobstructed exterior surface, will be appreciated by engineers. I

I claim 1. A sheet metal casing for culverts, wells and drainage purposes, comprising sectional Thus in Fig. 27, it is evident I and drainage purposes, comprising sectional units having an. lntermediateportion prounits having an intermediate portion pro-' vided with double walls weld-united at the ends of said portion and each of which is perforated, and imperforate single-walled end portions.

2. A sheet meta-l casing for culverts, wells,

vided with double walls rigidly united at the ends of said portion,and each of which is perforated, the perforations in the outer wall beingnarrow sheared slitsand the perforations in the inner wall being larger than those in the outer wall.

3. A sheet metal casing for culverts, wells and drainage purposes, comprising a tubu- 'lar memberhaving an intermediate portion provided. wlth double walls, each of which is'perforated, and spirally corrugated end portions, one end being tapered and the other end being correspondingly flared so that the tapered end of one section may be screwed into the flared end of another sect1on.

4. A sheet metal casing for culverts, wells and drainage purposes,rcomprising a tubular member havln I an intermediate portion provided with dou 1e walls which are weldunited, each of which is perforated, and single-walled end portions, and means for connecting adjacent casing sections together.

5, A sheet metal casing for culverts, wells and drainage purposes,'comprising a tubular memberhavin g an intermediate portion prosaid perforated intermediate portion.

ber provided with narrow. sheared slits, and

extending concentrically over said intermediate portion and having its ends rlgidly secured to said tubular member, the stralner member thereby forming a reinforce for 7. A sheet metal casing for culverts, wells and drainage purposes having double walls,

each of which is perforated and the perforations in one of the walls being narrow sheared slits.

8, A sheet metal casing for culverts, wells and drainage purposes having double walls with sheared 'slitsin one of the walls, portions of-said walls being spaced apart, thereby establishinga passageway for the fluid lengthwise of the drainage section.

In testimony whereof I affix my signature in presence of two witnesses.

, ANDREW SMITH.

Witnesses JAMES F. Ross, GUSTAV A. HERBST.

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