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Publication numberUS1387067 A
Publication typeGrant
Publication dateAug 9, 1921
Filing dateJan 6, 1921
Priority dateJan 6, 1921
Publication numberUS 1387067 A, US 1387067A, US-A-1387067, US1387067 A, US1387067A
InventorsMurray Thomas E
Original AssigneeMurray Thomas E
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of making a molded conduit
US 1387067 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)



1,38?,06? a Patented Aug. 1921.,


Application filed January 6, 1921.

To all whom it may concern:

Be it known that I, THOMAS E. MURRAY, a citizen of the United States, residing at Brooklyn, in the county of Kings and State of,New York, have invented a certain new and useful Improvement in Methods of Making a Molded Conduit, of which the following is a specification.

Conduits of cement or like plastic material have been molded upon a spiral core of wire or the like provided with a cover or wrapping of paper or similar flexible material. When the core is withdrawn after the cement has hardened, the paper is left in the bore. Where the conduit is used to convey water or other liquid, the paper is softened and eventually detached, and thus becomes washed into elbows, valves or smaller branch pipes-in all cases more or less choking these and so stopping or impairing the flow.

My present invention is a method of molding said conduits so that the paper cover becomes a lining permanently affixed to the surface of the bore and which cannot be loosened or washed away, thus avoiding the abovedescribed difliculty. My said method consists in the steps performed in the order stated more particularly in the claim.

In the accompanying drawing- Figure 1 represents in'longitudinal section a portion of the conduit and core there in. Fig. 2 is a similar view of said conduit after the removal of the core.

Similar numbers of reference indicate like parts.

In performing my method, I first make a spiral core 1 of wire or strip metal. Upon said core I apply, preferablyby wrapping,

Specification of Letters Patent.

Patented Aug. 9, 1921.

Serial No. 435,408.

a cover 2 of paper or similar flexible sheet material. To this cover I next apply a coating 3 of pitch or other viscid adhesive material which will h'arden. While the pitch coating is still viscid, I apply thereto plastic cement or concrete 4 to form the conduit body, and allow said plastic material to become hard. Finally, I withdraw the core l. The cover 2 remains firmly held by the pitch coating and said coating in turn uniteswith the cement surrounding it, so that the cement, the cover and the pitch form a solid hard mass, of which the coverforms a fixed lining having a smooth inner surface, and which is not washed away nor loosened by liquid flow in the conduit. The said mass, besides, is wholly of insulating material,

thus adapting the conduit to the conveyance of electrical conductors. Where the cement or concrete is at all porous, the pitch layer renders it impervious to both gases and liquids. I

I claim:

The method of making a molded conduit, which consists in, first, producing aspiral metal core; second, covering said core with flexible material; third, applying to said cover a coating of adhesive material; fourth. forming upon said coated core the conduit body'of plastic material and allowing the same to harden, and fifth, withdrawing said spiral core.

' In testimony whereof I have a-flixed my signature in presence of two witnesses.




Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2901775 *Sep 7, 1954Sep 1, 1959Zonolite CompanyMethod of insulating pipe
US3379591 *Dec 18, 1963Apr 23, 1968Richard C. BradleyFilament winding of tubular articles with incorporation of cut lengths of roving during winding
US4102972 *Nov 25, 1977Jul 25, 1978Tomiji TarukawaRefractory pipe fittings and production thereof
US5885508 *May 20, 1997Mar 23, 1999Terumo Kabushiki KaishaCatheter tube and a method of processing the inner surface of a tube
U.S. Classification264/135, 264/313, 425/468, 264/219, 138/175
International ClassificationB28B21/86, B28B21/00
Cooperative ClassificationB28B21/86
European ClassificationB28B21/86