Abstract: Better mechanical properties are achieved with tubes for shell and tube heat exchangers by providing a coating on the tubes which is formed of fibers and a fluorine-containing polymer covering the fibers. The tubes are formed of fluorine-containing polymers whose use in heat exchangers is normally limited by the comparatively small compressive strength and fatigue resistance of the tubes.

Abstract: A flexible coaxial conduit in a recirculating paint supply system disposed between a flow control restrictor connected to a paint spray nozzle and a pressurized paint supply line and return line for supplying paint to the nozzle in a quantity in excess of that required to insure continued recirculation and uniformity in the composition and quality of the liquid coating composition. The coaxial conduit is substantially transparent and in the preferred embodiments, the outer tube is of a composite construction to provide optimum flexibility while retaining resistivity to the attack from the liquid paint composition and from solvents.

Abstract: In a tubular structure for forming a fishing rod, an amorphous metal long fiber tape is spirally or crosswise wound on a prepreg sheet tube with a predetermined pitch, not being overlapped in each turn, so that the prepreg sheet and the amorphous long fiber tape are joined together with high adherence, whereby its twisting strength, collapsing strength and bending strength are improved.

Abstract: A polyvinyl choride resin pipe serves as an inner lining material for the existing pipes. The resin pipe is formed of a resin composition which comprises as a main component either a polyvinyl chloride having a degree of polymerization DP of 600 to 1,050, or a mixture of 40 to 60% by weight of a polyvinyl chloride having a lower average degree of polymerization DP.sub.L of 400 to 600 and 60 to 40% by weight of another polyvinyl chloride having a higher average degree of polymerization DP.sub.H of 1,050 to 1,350. The resin composition further comprises 3 to 25 parts by weight of a modifying agent blended with 100 parts by weight of the main component. The modifying agent is composed of MMA- and/or MBS-modifiers.

Abstract: In a construction material comprising a flexible carrier substrate impregnated or coated with a water-hardening resin, the resin contains as an additive polyether polysiloxane polyurethanes of the formula ##STR1## in which R.sup.1 is lower alkyl,m is the average number of siloxane groups in the range from 5 to 25,R is ##STR2## in which X is lower alkylene,Y is an aliphatic, cycloaliphatic, aromatic or araliphatic moiety, which is unsubstituted or substituted by further ##STR3## Z is a polyether moiety based on ethylene oxide units propylene oxide units, or both with the average number of ethylene oxide and propylene oxide units being in the range fro 10 to 100 andR.sup.2 is lower alkyl.

Abstract: A refrigerant transporting hose including a polyamide resin innermost layer, at least one intermediate rubber layer positioned radially outwardly of the innermost layer, a reinforcing fiber layer positioned radially outwardly of the intermediate rubber layer or layers, an outer tube which is positioned radially outwardly of the fiber layer and has at least one layer including an outermost layer, and at least one phenolic resin layer formed of a phenolic resin and having a total thickness within a range of 5-100 .mu.m. Each phenolic resin layer is provided at a corresponding one of interfaces between adjacent layers which are selected from the innermost layer, the intermediate layer or layers, the fiber layer and the layer or layers of the outer tube.

Abstract: An electroconductive composite tube assembly is provided. The assembly includes a metal end member having at least one cylindrical wall. A tube main body of PTFE and having an outer circumferential surface is further provided. The outer circumferential surface of the tube main body is disposed in engagement with an inner circumferential surface of the cylindrical wall of the metal end member. An electroconductive tube formed from a heat-shrinkable resin is disposed over the cylindrical wall of the metal end member and over the outer circumferential surface of the tube main body. The electroconductive tube is heat-shrunk into laminated engagement with both the cylindrical wall of the metal end member and with the outer circumferential surface of the tube main body to enable efficient grounding of the electrostatic charges developed in the composite tube.

Abstract: The method for lining a pipe laid in the ground, especially a sewer conduit made from concrete, asbestos cement or stoneware, comprises making a lining tube for the pipe with an outer layer and an inner layer made from fiber fleece and a barrier layer impermeable to fluid located between the inner layer and the outer layer. The outer layer is soaked with a stress-free hardenable plastic resin adhering well to the pipe in one or more regions of over its entire length and the inner layer is soaked with the same or another plastic resin having reduced shrinkage not impairing the outer layer. The lining tube is introduced into the pipe and pressed on the inner surfaces of the pipe to be sanitized. The plastic resin is hardened to form an adhesive bond between the pipe and the outer layer. Advantageously the outer layer is soaked with epoxy resin and the inner layer is soaked with polyester resin. The product of this method, a sanitized conduit, is also described.

Abstract: The molding has a body (3) of thermoplastic. A sound-muffling layer (4), which is affixed to the body (3) by the injection-molding process, consists of a thermoplastic elastomer. The body (3) protrudes at its end from the sound-muffling layer (4). Welding sleeves (2) are welded onto these unlayered areas (5) of the body (3). Molding (1) in the course of repair work can also be severed in the area of the sound-muffling layer (4) and joined by means of butt welding. The thickness of the sound-muffling layer (4) is comparatively small.

Abstract: A fuel delivery rail assembly for supplying fuel to a plurality of fuel injectors in an engine is provided. The assembly comprises an elongated conduit and a plurality of sockets. The conduit has a four-wall section consisting of a single aluminum wall and three steel walls. Opposing steel walls are provided with cavities for receiving edges of the aluminum wall. Abutment portions between the aluminum wall and the steel walls are mechanically shrinked from outside and combined tightly. The sockets are integrally formed with the aluminum wall through an aluminum die casting process. The steel walls can be made from a high damping steel element.

Abstract: A transfer tube is produced comprised of a high density ceramic oxide tube having a low density multi-layered ceramic oxide shell directly bonded to its outer surface wall.

Abstract: A tubular member having a liner adhesively affixed to an inner surface thereof. The liner comprises a porous material formed from a plurality of needle-punched unwoven fibers so as to have a pair of oppositely facing surfaces. The liner also includes a first mat of finespun woven filaments of glass defining an inner surface thereof and a second mat of finespun woven filaments of glass defining an outer surface thereof. The inner and outer surfaces of the liner, formed by the first and second mats, are generally coextensive with the porous material. The liner also includes the first mat being secured to an inwardly facing surface of the porous material and the second mat being secured to an outwardly facing surface of the porous material. The liner is adhesively impregnated so as to adhesively bond the outer surface of the liner to the inner surface of the tubular member. Further, a method of lining a tubular member by adhesively bonding a liner to the tubular member is disclosed.

Abstract: A transfer tube is produced comprised of a high density ceramic oxide tube having a low density multi-layered ceramic oxide shell directly bonded to its outer surface wall.

Abstract: A separating pot for glandless electrical or magnetic drive assemblies includes a pot jacket having a generally tubular body with two ends and a flange portion at one of the two ends, the pot jacket being composed of fiber reinforced plastic with the fiber being wound in alternating layers of circumferential windings and helical windings, and with the flange portion being composed of additional circumferential windings; a bottom member disposed within and closing off the other of the two ends of the pot jacket, the end of the pot jacket being an open end, the bottom member having a generally cup-shaped portion which includes a rim portion surrounding an interior bottom face, the rim portion facing the open end of the pot jacket and extending in an axial direction away from the interior bottom face, the bottom member being in a press fit with the pot jacket and being glued to the pot jacket, the rim portion having a generally conically-shaped interior surface which is enlarged in a direction away from the inte

Abstract: A rubber hose having an outer rubber tube and an inner rubber tube located radially inwardly of the outer rubber tube, the inner rubber tube including an inner layer and an outer layer located between the inner layer and the outer rubber tube, the inner layer being formed of a first polymer blend of acrylic rubber and fluorine-contained resin, the outer layer being formed of a second polymer blend which is different from the first polymer blend and which contains epichlorohydrin rubber. The rubber hose may further have a reinforcing fiber layer disposed between the outer rubber tube and the outer layer of the inner rubber tube such that the inner and outer rubber tubes and the fiber layer constitute an integral tubular body.

Abstract: Pipes and couplings for manufacturing pipelines comprising a wall having at least one layer of core material consisting essentially of a crosslinked polyolefin resin and at least one layer of surface material consisting essentially of a thermoplastic resin, said core material being crosslinked to a rate higher than 30%.

Abstract: A metallic outer sleeve 10 is provided which is capable of enveloping a hollow metallic inner member 12 having continuous reinforcing fibers 14 attached to the distal end thereof. Inner member 12 is then introduced into outer sleeve 10 until inner member 12 is completely enveloped by outer sleeve 10. A liquid matrix member 20 is then injected into space 22 between inner member 12 and outer sleeve 10. A pressurized heat transfer medium 23 is flowed through the inside of inner member 12, thereby forming a fiber reinforced matrix composite material 26. The wall thicknesses of both inner member 12 and outer sleeve 10 are then reduced to the appropriate size by chemical etching, to adjust the thermal expansion coefficient of the metal-clad composite structure 28 to the desired value.

Abstract: A heat deformable tube having a melt liner of noncross-liquid, thermoplastic material, such that upon heating to a temperature high enough to cause the tube to return to its original shape; the melt liner melts and encapsulates the substrate.

Abstract: Disclosed is a rigid or flexible conduit usable particularly for transporting fluids and enabling to limit the permeability to transported fluids. According to the invention, the conduit comprises at least an inner flexible sheath (1) made of thermoplastic, elastic, or rubber material and an outer sheath (10) comprising a metal layer (3) and arranged around said inner sheath (1). Said metal layer comprises at least a layer of flat metal band (3) which is spirally wound with a winding angle .alpha. higher than 50.degree. and lower than 90.degree. with respect to the axes of the conduit. For rigid conduits, said metal layer (3) is adhered to said inner flexible sheath (1) on the major part of the width of the band (3).

Abstract: An innerduct is disclosed which can fit inside a preexisting conduit and extend along the length thereof or can be directly buried with a plow or in an open trench, for receiving transmission cables and, in particular, fiber optic cables. The innerduct is formed by coextruding first and second materials, the material for the inner portion of the innerduct including a lubricous material impregnated therein so that friction is reduced between the inner surface of the interduct and cables which are pulled therethrough. Ribs can be provided on the inner and outer surfaces of the innerduct of the duct can be formed with undulated walls so as to further reduce friction between same and cables slid therethrough by minimizing the surface contact between these elments. The ribs and/or undulations also faciliate the dissipation of heat due to friction of assembly, heat during the extrusion process, and from ambient sources of heat.

Abstract: The present invention relates to a unique fiber-reinforced metallic tubular element, along with a unique method for producing such tubular elements on a production basis. The tubular element includes a cylindrical aluminum tube surrounded by a fiber composite sleeve which includes a plurality of individual reinforcing graphite fibers oriented parallel to the longitudinal axis of the tube and uniformly positioned about the circumference of the tube. In the preferred embodiment of the invention, an isolation layer is positioned between the graphite reinforcing layer and the outer surface of the aluminum tube, and a protective covering layer of fiber material surrounds the tube and is adhered to the outer surface of the graphite reinforcing layer. In the preferred method of the present invention, a plurality of cylindrical metal tubes are coupled to one another in an end-to-end relationship by a plurality of joining plug members to form a longitudinally extending series of metal tubes.

Abstract: A hose for transporting or otherwise handling refrigerants is disclosed which comprises an inner tube, an outer cover and a reinforcing layer disposed therebetween, the inner tube including a resinous inner wall and a rubbery outer peripheral wall. The inner peripheral wall is formed by a selected class of polymers having specified compositions, whereby the hose is rendered highly resistant to gas permeation and stress cracking and highly flexible and moisture-proofing.

Abstract: A process for producing hoses of laminated construction having a plastic inner tube is disclosed which comprises:- (a) extruding a thermoplastic resin on a mandrel to form an inner tube with a predetermined thickness, the mandrel being preformed of a thermoplastic resin or rubber and releasable from the inner tube, (b) laminating an outer tube integrally on the inner tube by extrusion of an unvulcanized rubber to form an integral hose body, (c) vulcanizing the hose body, (d) removing the mandrel from the vulcanized hose body. This hose is characterized by high resistance to load of impulse.

Abstract: There is provided a flexible composite hose constructed such that a plastics inner tube is covered with an outer tube of heat-shrinkable material, with the inner tube being compressed by the shrinkage force of the outer tube. It is produced by covering an inner tube with an outer tube having a slightly larger inside diameter than the outside diameter of the inner tube, and then heating the tube assembly at a proper temperature to effect heat shrinkage. It has good chemical resistance and pressure resistance.

Abstract: The invention provides a method of applying a resin impregnated lining sleeve to a length of passageway surface wherein the sleeve first of all has a carrier tube everted into the sleeve from one end and out of the other end, the carrier tube is re-inverted to draw the sleeve into the carrier tube and then the assembly of carrier tube and sleeve is positioned in relation to the passageway length to be lined and the carrier tube re-everted to position the sleeve on the surface in the required position. The resin is subsequently cured and the carrier tube removed leaving a hard tubular lining shell on the passageway surface.

Abstract: A curable resin coated sheet useful as an orthopedic bandage which has reduced tack is provided. The resin coated sheet is pre-lubricated with a lubricant which is (a) bonded to the resin, (b) added to the resin or applied to the surface of the coated sheet, or (c) a combination of (a) and (b). The lubricant is present in an amount to reduce the kinetic coefficient of friction of a surface of the coated sheet to less than 1.2.

Abstract: A Process is described for lining the inner surfaces of pipes or pipe sections using the Insituform method by pressing a tubular flexible laminate made up of an essentially liquid-impermeable membrane and a fibrous layer which has been impregnated with a binder which is not as yet fully cured with the face with the binder against the inner surface of the pipe by means of liquid pressure in such a way that the laminate takes on the shape of the inner surface of the pipe and the binder becomes fully cured in the state, forming a firmly adhering internal lining. The binder used according to the invention in this process contains(a) a curing agent which is a salt of one or more (poly)amines having at least one tertiary nitrogen atom and one or more aromtic polyols or one or more aliphatically substituted phenols, the aliphatic radical having at least 9 carbon atoms, and(b) a liquid epoxy resin or a liquid mixture of epoxy resins and can, if desired, also contain(c) further additives.

Abstract: A plastic pipe consisting of an outer corrugated plastic pipe and an inner smooth wall consisting of a wear resistant elastomer, particularly a thermoplastic rubber fixed in the inner bottoms wave valleys to said outer corrugated pipe. The inner wall consists of a pipe which has been coextruded with the outer corrugated pipe so that the inner and outer pipe are heat welded to each other.The cavities between the inner pipe and the corrugations may be filled with a foam plastic.This plastic pipe is used for repairing or renewing a sewage pipe by installing such a pipe from a vertical shaft of the sewage system into the sewage pipes. The interstices between the outer side of the corrugation and the inner side of the sewage pipe may be filled with a mortar.

Abstract: A method and apparatus for manufacturing a centrifugally cast pipe for use in a chemical and corrosive atmosphere is provided. The centrifugally cast pipe has an integrally cast socket or coupling at one end of the pipe. The socket is cast onto the pipe. At the same time that the pipe is cast, both socket and pipe are cured simultaneously, creating a homogeneous wall from body to socket through the transition zone.

Abstract: A fiber reinforced composite composed of a scrim/mat. The scrim/mat includes a layer of fiber scrim to which is bonded a layer of fiber mat. This product can be formed into a tubular member such as a fuse tube. The tube is made by pultruding the scrim/mat.

Abstract: A method of producing a glass-lined metal pipe in which an unconsolidated tal or metal alloy powder is loaded into a sealable glass mold comprising a graphite core, a glass sleeve slipped over the graphite core with a sliding fit, a sealable outer glass envelope surrounding the graphite core and glass sleeve forming with them a sealable chamber for the metal or metal alloy powder, wherein the glass is a type which becomes plastic when heated. The air in the mold is removed under vacuum and the mold is sealed and placed into a free flowing refractory powder in a crucible and consolidated by sintering under atmospheric pressure (CAP.RTM. process). Removal of the glass envelope and the graphite core produces a glass-lined pipe in which the glass liner is slightly fused into and is under compressive force from the surrounding metal pipe.

Abstract: A self-contained, transportable apparatus for inserting a flexible liner having a leading end and a trailing end into a pipe comprises an inversion means or insertion conduit, and means for sealingly clamping the leading end of the liner with a fluid tight seal to the insertion conduit or inversion means. A conveyer means having an entry end and an exit end is provided for conveying the liner to the insertion conduit or inversion means. In one embodiment, the conveyer means is comprised of a single conveyer which is movable between a generally horizontally oriented transport position and a generally sloped operating position. Another embodiment of the invention comprises two separate conveyers aligned in end-to-end relation, the two conveyers being movable between a transport position in which both conveyers are generally horizontally oriented, and an operating position in which the distal ends of the conveyers are higher than the remainder of the conveyers.

Abstract: A blast pipe (2) primarily intended for introducing gas, such as oxygen gas, into molten metal in metallurgical processes, such as steel manufacturing processes, including a pipe element (1) made preferably of steel and coated at least externally with at least one protective layer (3). The blast pipe (2) is particularly characterized by the fact that the pipe element (1) is provided with an external, preferably high compact layer (3,4) which mainly comprises organic fibres, preferably wood fibres in the form of paper, and by the fact that the fibre layer (3,4) is preferably completely or partially impregnated with a refractory substance.

Abstract: A shrinkable tubular article comprises a tubular inner elastomeric member held in a radially expanded configuration by a tubular outer restraining means. The restraining means is prepared from a blend of a relatively rigid thermoplastic material and a segmented copolymer having at least one segment compatible with the thermoplastic and at least one segment compatible with the elastomer of the inner member. Optionally, the restraining means contains a tackifier. The inner surface of the outer member and the outer surface of the inner member are directly bonded together (i.e. without an interfacial adhesive). The bond between the members is sufficiently strong to restrain the inner elastomer member from shrinking to, or toward, its unexpanded configuration. In addition, the bond weakens sufficiently on application of solvent to permit the elastomeric member to peel away from the restraining outer member.

Abstract: A precompounded formulation that acts as an adhesive layer when subjected to heat and pressure in contact with thermoplastics such as polyethylene or polyvinyl chloride and elastomeric materials such as EPDM or chlorobutyl rubber. The formulation incorporates a formaldehyde donor/acceptor system such as resorcinol and hexamethoxymethylmelamine. The formulation is further comprised of a blend of thermoplastic materials, the composition of which varies depending upon the type of material that the bonding layer is required to adhere to. The formulation will also adhere to thermoplastic elastomers (TPE) making it feasible to manufacture a hose article with elastomeric and thermoplastic layers bonded together by the formulation without the need to vulcanize the article. Heretofore, thermoplastic elastomers were thought to be incapable of adhering to dissimilar materials without the application of a tackifier or an adhesive or glue-like material.

Abstract: Pipelines for transporting sewage, water, slurries, liquid and gaseous hydrocarbons, and like materials are interlined with a composite tubular lining having an inner skin layer and a foamed layer contiguous with the inner skin layer. The foamed layer is either contiguous also, along its opposite surface, with the inner wall of the pipe or may be spaced therefrom by an outer skin layer of the composite lining. The lining may be applied either before the pipeline is placed into service or afterward, whether in situ or removed for maintenance or repair. For application in situ the lining is preferably more flexible than will suffice for insertion into new pipes.

Abstract: A heat recoverable tubular composite article comprising an inner layer comprising a crosslinked elastomeric polymeric material having a modulus at 100% elongation at 20.degree. C. of about 40 to about 900 pounds per square inch and an outer layer comprising a thermoplastic material having a 2% secant modulus at 20.degree. C. of about 5,000 to about 100,000 pounds per square inch said composite article (1) being formed by coextrusion, (2) having a direct bond between said layers with a peel strength of at least 6 pounds per linear inch, and (3) being in a radically expanded configuration, said thermoplastic outer layer being capable of retaining the elastomeric inner layer in an expanded configuration at ambient temperature and incapable of retaining the elastomeric layer in an expanded configuration at a temperature above a predetermined temperature thereby permitting the composite article to recover to or toward its unexpanded configuration.

Abstract: This invention is concerned with a hose construction particularly suitable for Freon service in refrigeration systems. The hose comprises (1) a core tube of polyamide covered by an elastomeric friction layer such as EPDM rubber having incorporated therein a calcium ion source and an adhesion system and a curative, (2) a layer of tensioned reinforcement strands, (3) an adhesive/barrier/friction layer such as an ethylene acrylic acid copolymer, (4) a second layer of tensioned reinforcement strands, and (5) a cover selected from chlorobutyl rubber or other suitable materials wherein the chlorobutyl rubber utilizes a bis-dienophile as a crosslinker.

Abstract: A hydraulic brake hose has an inner tube made of nylon, an isocyanate adhesive layer formed on the outer surface of the inner tube, a chloroprene-rubber adhesive layer formed on the outer surface of the isocyanate adhesive layer, a reinforcing fiber layer made of high polymeric material selected from the group consisting of rayon, polyester, polyamid and polyvinyl alcohol, impregnated with resorcinol formaldehyde latex containing chloroprene-rubber and formed on the outer surface of the chloroprene-rubber adhesive layer and an outer tube made of chloroprene-rubber and formed on the outer surface of the reinforcing fiber layer. The inner tube has the modulus of elasticity of 7,000 to 15,000 kg/cm.sup.2 and has an inner diameter of not less than 2.0 mm, an outer diameter of not more than 6.0 mm and a thickness of not less than 0.7 mm.

Abstract: An example of an elastomeric article embodying the invention is a composite, reinforced, vulcanized elastomeric hose, which includes a tube, an outer cover, a reinforcement layer, and a specially compounded interlayer interposed either between the tube and the reinforcement or the cover and the reinforcement. The inner tube (or in some applications, the cover) is composed of either a fluoroelastomer, fluoroplastic, polypropylene, polyvinylchloride, chlorinated polyethylene, or acrylonitrile polymer. The compounded polychloroprene interlayrer effects a strong bond to these materials. The tube and the cover are composed of materials not readily bondable to each other. The polychloroprene interlayer forms a strong bond to those layers it is in contact with when vulcanized.

Abstract: A plastic pipe comprising an oxygen-impermeable casing, wherein the casing comprises a barrier layer for oxygen, and an adhesive layer adjacent to the circumferential surface of the pipe and attached to the circumferential surface by an sealed bond, wherein the casing surrounds the circumferential surface on all sides, and wherein the barrier layer is elastic, is substantially impermeable to oxygen and comprises a polyvinyl alcohol, a vinyl alcohol/ethylene copolymer, or polyacrylonitrile. Also disclosed is a process for the production of the pipe and a use of the pipe as a heating pipe.

Abstract: The invention relates to a heat insulating piece comprising a transporting duct of a storage enclosure for liquids or gases, and a heat insulating covering.At least one layer of heat insulating material is deposited on the outer surface of the wall of the duct or of the enclosure, and an outer wall is disposed around said layer and is maintained with stiffeners which also reinforce the structure of the piece.

Abstract: A pipe cluster unit comprises a plurality of plastic pipes arranged parallel to one another and being in mutual engagement with one another along longitudinal lines of contact to form a pipe cluster and a cover layer bonded to external surface portions of the pipes. The cover layer connects adjoining pipes to one another by bridging the adjoining pipes at locations spaced from respective lines of contact between adjoining pipes.

Abstract: A method is described for curing an elastomeric tubular article having a thermoplastic jacket thereon. The curing is achieved either by heat or by microwave radiation. After curing, the thermoplastic jacket is removed.

Abstract: A length of longitudinally extending duct assembly for heated corrosive gases includes an outer support duct and a substantially gas-tight liner. The liner is spaced from the outer support duct by a relatively yielding spacer material that accommodates expansion of the liner in directions parallel to the inner surface of the outer support duct and in directions normal to the inner surface of the outer support duct without imposing any substantial resistance to such thermal expansion.

Abstract: A hollow filament wound tube having a plurality of cylindrical, hollow, open ended load bearing shells embedded between radially spaced layers of fiber of the filament wound tube, the shells having a longitudinal dimension less than that of the filament wound tube.

Abstract: A process for manufacturing a sealant coated heat recoverable polymeric article is disclosed. The process includes the steps of extruding at least two different polymeric materials to form a unitary shaped article and thereafter exposing the shaped article to a source of ionizing radiation to thereby cross-link one of the polymeric materials and convert the other polymeric material into a tacky sealant.

Abstract: A method for obtaining a positive bond between articles painted or coated with thermosets and concrete, involves treatment of the surface with an epoxy resin-cement mortar mixture containing an epoxy resin emulsion of the composition(a) a liquid epoxy resin;(b) water;(c) an emulsifier comprising a primary, aliphatic alcohol, an adduct thereof with ethylene oxide or, optionally, a polyglycol ester of a carboxylic acid; and(d) a latent curing agent comprising a reaction product of the essentially complete neutralization of a diamine of the formulaeH.sub.2 N--CH.sub.2 --R--NH.sub.2orH.sub.2 N--R--CH.sub.2 --R--NH.sub.2with oxyalic acid,wherein R is alkyl substituted alkylene or cycloalkylene; or the reaction product obtained by complete neutralization with oxalic acid of (i) a polyamine of the formulaH.sub.2 N--CH.sub.2 --CH.sub.2 --NH--.sub.x Hwherein x=2, 3, or 4, or of (ii) a reaction product, containing amino groups, of such a polyamine with a fatty acid.

Abstract: A flexible hose comprising a main fluid retaining carcass and a secondary carcass enclosing at least part of the main carcass, said secondary carcass being constructed to expand radially relative to said main carcass on leakage of fluid from said main carcass. Said hose includes means to control the radial expansion of said secondary carcass in a predetermined manner; said means may comprise localized bonding of said main and secondary carcasses and/or localized circumferential reinforcement of the secondary carcass.

Abstract: A concrete pipe of the type employed, for example, in large sewers is described, having a concrete wall and an inner lining sheet of a polymeric or other plastic material anchored to the wall by a layer of fabric welded or otherwise firmly connected to the sheet. The fabric includes a plurality of preferably monofilament projections having a higher modulus of elasticity than the material of the sheet which projections extend into the inner wall of the concrete pipe and anchor the fabric and sheet thereto. A protective plastic ring and a covering strip positively support the sheet at the joint between two pipes.