Abstract: This new sewer cleaning hose is a rubber hose that concentrates on the ability to improve flexibility and cover resistance to cutting and abrasion while providing a six inch minimum bend radius. What makes this hose design unique is the low friction the hose cover offers under operation. No other sewer hose offers the easy capability of routing through sewer applications like the proposed new hose design. The hose comprises an inner tube of an acrylonitrile rubber and an outer cover of UHMW plastic.

Abstract: A heat-resistant hose for transport of high temperature fluid, wherein the inner surface of the hose in contact with said fluid comprises a material containing blended rubber of fluorinated rubber (FKM) and acrylic rubber (ACM). In particular, a heat-resistant hose for transport of fluid containing high temperature oil which comprises an inner tubular body composed of one or more layers at least the most inner layer of which consists of blended rubber of FKM and ACM, fiber reinforcements wound around the outer surface of said inner tubular body the thread extracting force of which the fiber reinforcements is not less than 1N/mm, and an outer tubular body composed of one or more layers bonded on the surface of said fiber reinforcements, said most inner layer preferably containing carbon black having the value (A.times.B) of not more than 3500 obtained by multiplying the value A of nitrogen adsorption specific surface area (m.sup.

Abstract: A pipe or hose (10) intended primarily for fire protection purposes and capable of withstanding high heat flux densities. The pipe or the hose has an internal, tubular rubber layer (11) and a casing (12) provided with holes which casing embraces the tubular rubber layer (11) in close contact therewith. The holes in the casing (12) are situated close together and have a limited cross-sectional area such that liquid transported in the pipe or hose (10) at a current liquid pressure above atmospheric pressure and through the medium of a nozzle effect in direct contact with the casing (12) and, subsequent to release from said casing contact, is able to form a free-standing liquid jet. When used in sprinkler systems or like fire extinguishing systems, the pipe or the hose will be imparted herewith self-sealing and self-protecting properties, and will withstand a heat flux density caused by a jet fire of up to about 500 kW/m.sup.

Abstract: A reinforced pressure hose for use in boring or other construction work comprises a rubber core tube, a rubber cover tube or sheath and a plurality of reinforcing layers interposed therebetween and adapted for reinforcement against pressure imposed upon the core tube, reinforcement against tensile load and reinforcement further against wear of the hose. The tensile reinforcing or bearing layer is formed from a web of organic fibers knitted at a selected bias angle such that the hose can withstand increased tensile forces while retaining sufficient flexibility to facilitate bending as when it is taken up on a reel. The bias angle relationship between the various reinforcing layers is set so as to allow easy removal of the hose from a mandrel.

Abstract: A fuel transporting hose used in a fuel pipe system is disclosed which includes: an inner layer made of a fluorine-contained resin; an intermediate layer made of a rubber material and formed on an outer surface of the inner layer; a fiber reinforcing layer formed on an outer surface of the intermediate layer; and an outer layer made of a rubber material and formed on an outer surface of the intermediate layer. The intermediate layer has a thickness which is 3 to 30 times as that of the inner layer, and the outer layer has a thickness which is 3 to 35 times as that of the inner layer.

Abstract: A laminated air brake tubing includes inner and outer nylon layers with an intermediate fiber reinforcing layer. The tubing further includes one and preferably two layers of high density polyethylene positioned adjacent either of said nylon layers with a protective layer separating the fiber reinforcing layer from the high density polyethylene layer. The protective layer is preferably a thin layer of nylon or nylon alloy. Further, the high density polyethylene layer may include compatibilizing agents preventing delamination. The air brake tubing of the present invention meets the current requirements for air brake tubing, however it is less expensive than currently available air brake tubing.

Abstract: A thermoplastic and elastomer composite product, in particular a pipe for conveying coolant fluid in a motor vehicle air conditioning circuit, the product comprising an inside layer made of a mixture of a polyamide 6 and at least one modifying agent such as a grafted poly(1,2-vinylbutadiene), a polyoctene, a brominated isobutylene-p-methylstyrene, a silane, or an ethylene and acrylic acid copolymer, and a layer of an elastomer such as a brominated butyl rubber modified by a grafted poly(1,2-vinylbutadiene), a silane, an ethylene and acrylic acid copolymer, or a copolymer of ethylene and of propylene grafted with maleic anhydride, there being total adhesion between the thermoplastic and the elastomer.

Abstract: A laminated air brake tubing includes inner and outer nylon layers with an intermediate fiber reinforcing layer. The tubing further includes one and preferably two layers of high density polyethylene positioned adjacent either of said nylon layers. The polyethylene layers are cross-linked preferably by irradiation. Further, the high density polyethylene layer may include compatibilizing agents preventing delaminating. The air brake tubing of the present invention meets the current requirements for air brake tubing, however it is less expensive than currently available air brake tubing.

Abstract: A refrigerant conveying hose, being wholly made of a synthetic resin, is formed of an inner tube forming an inner side layer, an intermediate layer on the outer periphery surface of the inner tube, a fiber reinforced layer on the outer periphery surface of the intermediate layer and an outer tube forming the outer covering layer.

Abstract: The invention relates to a fiber-reinforced rubber hose having an inner tubular portion made of a first rubber; an outer tubular portion which is made of a second rubber and surrounds the inner tubular portion; and a reinforcing layer interposed between the inner and outer tubular portions. At least one of the first and second rubbers is a carboxyl-containing acrylic elastomer prepared by vulcanizing a carboxyl-containing acrylic copolymer. The reinforcing layer is prepared from polyester fibers containing terminal carboxyl groups which are in an amount of up to 20 equivalents per metric ton of the polyester fibers. The rubber hose can be produced with a relatively low cost due to the use of polyester fibers. Furthermore, the rubber hose is superior in metal contact resistance and calcium chloride resistance, in addition to satisfactory heat resistance, oil resistance, pressure resistance and sealing capability.

Abstract: A reinforced rubber hose including an inner tube and a reinforcing yarn layer externally contacting the inner tube. The inner tube includes at least an inner-tube inside layer and an inner-tube outside layer, the inner-tube outside layer being formed of a vulcanized diene rubber composition, the inner-tube inside layer being formed of a vulcanized hydrogenated nitrile rubber composition. Both the diene rubber compound and the hydrogenated nitrile rubber composition are vulcanized by a sulfur vulcanization agent. Further, the diene rubber composition contains about 5 to 25 phr of talc, wherein the talc has an average particle diameter of about 1 to 5 .mu.m and an aspect ratio of about 5 to 20.

Abstract: A fuel transporting hose used in a fuel pipe system is disclosed which includes an inner layer made of a fluorine-contained resin, and an outer layer made of a rubber material and formed on an outer surface of the inner layer. The outer layer has a thickness which is 5 to 30 times as that of the inner layer.

Abstract: Refrigerant transporting hose comprising an inner tube formed of a rubber composition based on an isobutylene.p-methylstyrene copolymer in which part or all of the p-methylstyrene units are brominated, and an outer tube around the inner tube with a reinforcing layer interposed, is improved not only in softness and resistance to the permeation of refrigerants but also in vibration and sound absorbing characteristics.

Abstract: This device is a hose for air conditioning purposes that is a barrier hose. The hose comprises an innermost tube of a thermoplastic vulcanizate. The innermost tube of thermoplastic vulcanizate is coextruded with a flexible polyamide barrier material as a second tube. A backing of thermoset rubber is extruded or calendared over the polyamide barrier tube. A reinforcement layer follows which is then covered with an EPDM outer cover.

Abstract: A twin tube air brake hose for delivering compressed air to brakes on a vehicle such as a truck includes a first tube which serves as a service tube and a second tube which serves as an emergency tube. The first tube and second tube have an inner layer surrounded by a reinforcing layer which is in turn surrounded by an outer rubber layer. The outer rubber layers of each tube are joined by a web which is unitary with the outer layers. Adjacent opposite ends of the twin tube brake hose, the tubes are separated to form free end portions, each of which have a metal fitting. Reinforcing bands are fitted around the twin tube air brake hose just inboard the tail ends to prevent the web from splitting.

Abstract: A flexible tube (10), in particular for use in oleodynamic circuits, comprises a substrate shaped in the form of a tubular core (12) around which at least one reinforcing layer (14) is arranged. The substrate (12) comprises a radially internal layer of elastomeric material extruded longitudinally (16) and a radially external layer (20) obtained as a result of winding a strip of rubber-coated fabric spirally around the internal layer (16).

Abstract: An improved reinforced hose for conducting fluids and gases, and a method of manufacturing that hose, are disclosed herein. The improved reinforced hose includes an interior tube having an inner bore and an outer surface. The improved reinforced hose also includes an outer covering disposed directly about the outer surface of the interior tube. Such outer covering includes one or more layers of plastic threads, which are formed by disposing a plastic substance about core material. The improved reinforced hose may be used as an electrically insulating connection between a city water main or other water supply line and an appliance such as a water heater.

Abstract: A pipeline structure with a lining material wherein a hermetic outer tube is disposed at the inner surface of a pipeline, and an inner lining material is disposed at the inner surface of the outer tube, said inner lining being made of a rigid fiber-reinforced plastic wherein a thermosetting resin is reinforced by a fiber reinforcement material.

Abstract: A high pressure hose for refrigerant made up ofan internal resin tube;an inner rubber layer, which is applied to an outer circumference thereof;a first reinforcing layer comprising a first splicing yarn, which is spirally wound around an outer circumference thereof;a second reinforcing layer comprising a second splicing yarn, which is spirally wound in the opposite direction to the first reinforcing layer around an outer circumference thereof; and,an outer rubber layer, which is applied to an outer circumference thereof,the inner rubber layer comprising rubber material whose 50% modulus M.sub.50 at a temperature of 135.degree. C. is 20 to 40 kgf/cm.sup.2.

Abstract: A hose useful for handling low temperature fluids such as refrigerants is disclosed, which exhibits excellent resistance to ozone and moisture permeation. A cover or outermost tube of the hose is formed from a vulcanizate of a rubber composition comprising a first copolymer rubber having an isobutylene unit and a p-halogenated methylstyrene unit and/or a second copolymer rubber having an isobutylene unit, a p-halogenated methylstyrene unit and a p-methylstyrene unit.

Abstract: An improved reinforced hose for conducting fluids and gases, and a method of manufacturing that hose, are disclosed herein. The improved reinforced hose includes an interior tube having an inner bore and an outer surface. The improved reinforced hose also includes an outer covering disposed directly about the outer surface of the interior tube. Such outer covering includes one or more layers of plastic threads, which are formed by disposing a plastic substance about core material.

Abstract: An oil hose comprised of (i) an inner layer made of a vulcanized hydrogenated nitrile rubber composition, an intermediate layer made of a vulcanized unsaturated nitrile-conjugated diene copolymer rubber composition, and an outer layer made of a vulcanized ozone-resistant rubber composition, or (ii) an inner layer made of a vulcanized rubber composition comprising a hydrogenated copolymer rubber composed of an unsaturated nitrile, a conjugated diene and a copolymerizable ethylenically unsaturated monomer, and an outer layer made of a vulcanized ozone-resistant rubber composition. This hose has good oil resistance, thermal resistance and copper ion resistance, and caulking in the portion thereof connected to a copper pipe is strong and oil leakage at a low temperature is prevented.

Abstract: Elastomeric vehicle hoses based on ethylene, alpha-olefin, vinyl norbornene elastomeric polymers will exhibit improved cure state and improved long term heat aging. Long term heat aging is an important consideration, as vehicle lives get longer and under the hood temperatures get higher. Also, such elastomeric based hoses will have improved compression set under a wide range of service temperatures. Such excellent compression set values lead to improved sealability over a wide temperature range. Additionally, these elastomeric polymers exhibit lower compound viscosity leading generally to improved processability.

Abstract: A woven single jacket elastomer lined fold flat fire hose comprised of fibers having a burst strength of at least 750 p.s.i., a melting point of at least 400.degree. C., and a weight of between 0.05 and 0.08 lbs per foot.

Abstract: A pipe comprising a multilayer inner core (1) whose outer layer is made of polyamide or of EVOH to provide an effective barrier function, and outer reinforcement that withstands pressure. The outer reinforcement comprises at least one filamentary reinforcing structure (4) placed around the core (1), a covering outer layer (7), and at least one bonding agent (3, 5) for bonding the reinforcing structure (4) to the inner core (1), the agent being selected from polyurethane or polyamide hot melt adhesives and thermosetting polyesters.

Abstract: A laminated hose is present which is suitable for a fuel conducting hose or other hose, or diaphragm, used for example in an automotive vehicle, which structure is required to have excellent heat resistance and gasoline permeation resistance while maintaining suitable properties of bonding and flexibility. The hose is constituted by an inner veneer layer of THV, a terpolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride, as a permeation barrier layer. This inner layer is reinforced by an elastomeric tie layer, a reinforcing layer and an elastomeric cover.

Abstract: A reinforced hose includes an inner tubular rubber layer, a cover layer made of rubber, and at least two reinforcing thread layers, including an upper thread layer and a lower thread layer, disposed between the inner tubular rubber layer and the cover layer. At least the lower thread layer includes a polyester thread having the following physical properties: a tensile strength of 8 grams or more per a unit denier, an elongation of 10.+-.1.5%, and a loaded elongation of 2.7.+-.1.0% per a unit denier under 3-gram load. With this construction, the reinforced hose satisfies the fatigue resistance and volume expansion requirements simultaneously.

Abstract: A reinforcing-thread-buried resin pipe has a structure in which, by using a device of burying reinforcing threads, one or more reinforcing threads different in color from a number of reinforcing threads are mixed in the reinforcing threads or one or more filaments different in color from a number of reinforcing threads are mixed in the reinforcing threads.

Abstract: Polyfluorocarbon/elastomer bonded laminates are disclosed. Flexible, durable chemical-resistant hose for use in industrial applications, and improved construction for such hose including inner tube members characterized by a dual-layer feature employing such laminate, is also disclosed. This feature comprises an adhesive elastomeric composition which bonds a polyfluorocarbon thermoplastic veneer to a substantially non-polar chemical-resistant carbon-based elastomeric or thermoplastic elastomeric outer layer. The adhesive elastomeric composition useful in the present invention comprises unsaturated polymeric dicarboxylic acids, or derivative adducts, of ethylene propylene diene terpolymer.

Abstract: The present invention relates to a hose construction containing a fluoroplastic barrier. The hose comprises (1) an inner core comprising (a) acrylonitrile-butadiene rubber and (b) from 0.05 to 25 phr of unsubstituted or substituted phenol salts of 1,8-diazabicyclo-[5,4,0]undecene-7; (2) a barrier layer comprised of a terpolymer derived from tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride, wherein said barrier layer is directly adhered to said inner core; and (3) an elastomeric cover.

Abstract: The invention is directed to a hot water resistant pressure hose (1) comprised of an inner tubing (2) made of an elastomer safe for use with food, preferably silicone, whose outer surface (3) has wound around it a plurality of multifilament polyester yarns (7, 8) forming a braid structure (4). This results in a braiding (4) having meshes (6) for establishing a positive-engagement bond between the inner tubing (2) and an outer tubing (9) made of an elastomer, preferably silicone, that is applied to the braiding (4). The outside diameter D of the inner tubing (2) is smaller than or equal to 6 mm, preferably 4.7 mm. For each winding direction, 10 to 15, preferably 12 polyester yarns (7, 8) are used, with the polyester yarns (7, 8) having a diameter that results at a weight of 250 den, minimum, and 310 den, maximum, preferably 280 den. Further, each mesh (6) is to cover an area of between 0.25 mm.sup.2 and 2.25 mm.sup.2, preferably 1 mm.sup.2. A pressure hose (1) is obtained which is hot water resistant (95.

Abstract: A hose for automotive fuel piping has an inner layer formed of a molding of a terpolymeric fluoro-resin prepared from tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride, so that it can be provided with suitable flexibility. Both the vulcanization composition of an epichlorohydrin rubber or NBR/PVC blend to be disposed outside the inner layer and the vulcanization composition of an NBR rubber or fluororubber to be disposed inside the inner layer contain 1,8-diazablcylco(5.4.0)undecene-7 salts and organophosphonium salts. A satisfactory bonding strength can be attained merely by the vulcanlzation bonding without any surface treatment such as corona discharge on the surface of the inner layer fluororesin.

Abstract: The present invention provides a composite or hose which minimizes hydrocarbon emission in fuel systems. The composite or hose is especially suitable for motor vehicles. The composite or hose uses a thin, inner layer of a polyfluorocarbon polymer and an outer layer of a thermoplastic elastomer.

Abstract: A laminated hose is present which is suitable for a fuel conducting hose or other hose, or diaphragm, used for example in an automotive vehicle, which structure is required to have excellent heat resistance and gasoline permeation resistance while maintaining suitable properties of bonding and flexibility. The hose is constituted by an inner veneer layer of fluorovinylidene-hexafluoropropylene backed by a thin layer of Teflon. These layer are then reinforced by an elastomeric tie layer, a reinforcing layer and an elastomeric cover.

Abstract: The present invention relates to a composite flexible hose excellent in pliability without any adhesive layer between an innermost layer and an intermediate rubber layer. The hose consists of the innermost layer, the intermediate rubber layer, a fibrous reinforcement layer and an external rubber layer, each of which is formed in this order from the inside. The innermost layer is formed of a modified polyamide obtainable by blending of a polyamide and a carboxyl-containing modified polyolefin, and the intermediate rubber layer is formed of a rubber composition obtainable by a blend of 10 to 50 parts by weight of silicic acid or a salt thereof and 5 to 15 parts by weight of a brominated alkylphenol formaldehyde resin per 100 parts of the rubber material obtainable by blending butyl rubber and a halogenated butyl rubber at a weight ratio of 50/50 to 0/100. The composite flexible hose is completed by vulcanization after laminating each layer.

Abstract: The invention discloses a hose (10) which comprises at least one tubular layer (3) of plastic or rubber material, a mesh-network (4) of the chain type presenting mesh lines (5) and mesh rows (6) having a tubular shape being wound on the external surface of said inner layer, a possible external layer (7), and is characterized in that said mesh rows are slanted in relation to the longitudinal axis of the hose. According to a preferred embodiment the lines (5) of said meshes are slanted in relation to the longitudinal axis Y of the hose, following a direction opposite to the direction of the mesh rows (6).

Abstract: A new curable compounded halopolymer that exhibits in the cured state good to excellent adhesion to polyamides. These curable halopolymer achieves better adhesion due to a balance of carbon black relative to talc, preferable with the cyclohexyl benzothiazole sulfenamide or related benzothiazole sulfenamide and are highly desirable in making specialty hoses and belts.

Abstract: An hydraulic brake hose such as for automotive applications is formed of an EPDM elastomer core tube and one or more additional tube layers, each formed of such terpolymer compounded without processing oils and one or more interlying reinforcing layers of nonwater-base adhesive coated polyvinyl alcohol fibers. The absence of water from the reinforcing fibers provides thennal stability to the reinforcing layers, and the absence of compounding oil from the EPDM terpolymers also provides high temperature properties for the hose.

Abstract: A fluid conveying hose, especially a refrigerant conveying hose, that exhibits improved resistance to permeation of the refrigerant while still affording desirable flexibility, and a fitting for such hose and methods of making the hose and the union between the hose and fitting. Also provided is a coupling assembly for a hose and a service fitting that is a considerably less expensive alternative to existing assemblies equipped with relatively expensive shut-off valves or quick connect/disconnect couplers.

Abstract: Process for the manufacture of a flexible polymeric structure comprising a sealant barrier, consisting of a multilayer film a few microns thick, oriented longitudinally, in a continuous manner, whereby all of the components of said flexible structure are intimately bonded by a final heat treatment. Flexible polymeric structures manufactured according to this process. Application to the fields of the transport of all fluids and protection against external aggressive agents.

Abstract: Process for the manufacture of a flexible tubular structure comprising a sealant barrier, consisting of a monolayer film a few microns thick, oriented longitudinally, in a continuous manner, whereby all of the components of said flexible structure are intimately bonded by a final heat treatment. Flexible tubular structures realized according to this process. Application to the fields of the transport of all fluids and protection against external aggressive agents.

Abstract: A reinforced hose has an inner tube made of rubber, an inner reinforcing layer made of aromatic polyamide yarn formed on the inner tube, an intermediate layer made of rubber formed on the inner reinforcing layer, an outer reinforcing layer made of synthetic yarn formed on the intermediate layer which has a heat shrinkage ratio at dried condition of over about 0.5% due to the temperature of a curing process, and a covering layer made of rubber being formed on the outer reinforcing layer. By providing the inner reinforcing layer of aromatic polyamide yarn, the reinforced hose of the present invention has a high stretching strength. Furthermore, by making the outer reinforcing layer of synthetic yarn, which has a heat shrinkage ratio at dried condition of over about 0.5% due to the temperature of a curing process, the reinforced hose of the present invention can hardly be expanded by the pressure of inside fluid.

Abstract: A composite hose is disclosed which is constructed essentially with an inner tube and an outer cover, the inner tube being formed from a composition comprised of a specified polymer alloy of a selected class of polyamide resins and acrylic rubbers and the outer cover from a composition comprised of a specified thermoplastic elastomer of a selected class of polyolefin resins and ethylene-propylene-diene rubbers and butyl-based rubber. Impermeability is greatly improved with respect to refrigerant gases and fuel oils.

Abstract: A refrigerant transporting hose having a laminar structure including an inner tube consisting of at least one layer, an outer tube disposed radially outwardly of and coaxially with the inner tube, and a reinforcing fiber layer interposed between the inner and outer tubes. The inner tube includes a resin layer formed of a resin composition which consists of a blend of modified polyolefin and polyamide resin, and 1-10% by weight of .epsilon.-caprolactam. A proportion by weight of the modified polyolefin to the polyamide resin is selected within a range between 40/60 and 10/90. The hose may have a sealing layer formed on the inner surface of the inner tube. The sealing layer consists of a chlorinated elastomer containing a dispersion of an acid receptive agent. Alternately, the sealing layer may be provided on the outer surface of a hose connector nipple.

Abstract: A fiber-reinforced rubber article has a rubber body portion with a fiber reinforcement embedded therein. The fiber reinforcement includes a plurality of tubular braided cords braided by yarns. Each of the tubular braided cords is braided by more than three yarns at a braid angle in a range between 10.degree. and 35.degree., wherein said braid angle is an angle between a yarn of the tubular braided cord and the axial line of the tubular braided cord. Each tubular braided cord also has a fistulous center hole defined by the tubular braided cord.

Abstract: A heat resistive sleeve (10) is capable of surrounding conduits, hoses and the like. The heat resistive sleeve (10) includes one outer layer (20) and, if necessary, a plurality of inner layers (12, 30, 38), all of which are fabricated of interwoven fiberglass yarns. To increase the insulating properties of the fiberglass, fibers of a second outer fiberglass yarn (24) are braided together to form a solid braid (26) having a radial thickness (T2) greater than the radial thickness (T1) of a first outer fiberglass yarn (22). A second inner layer (30) includes a first untextured fiberglass yarn (32) interwoven with a third textured fiberglass yarn (34), the textured fiberglass yarn (34) being less dense and having a radial thickness (T3) greater than the radial thickness (T1) of the untextured fiberglass yarn creating additional spaces (36) which further increase the thermal insulation of the heat resistive sleeve (10).

Abstract: A method for manufacturing a heat-shrinkable hose, wherein at least one shrinkable thread is wound around a basic hose element. A cover hose is provided that surrounds the basic hose element and overlies the heat-shrinkable thread. Longitudinal supporting threads can be provided for additional reinforcement.

Abstract: High performance hoses are disclosed which are characterized by enhanced heat resistance, leading to prolonged service life, and hence are suitable for use in automobile power steering units. Inner tubes are formed of hydrogenated acrylonitrile/butadiene copolymer rubbers of a selected composition. The inner tubes may be of a double-layered construction composed of an inner layer of hydrogenated acrylonitrile/butadiene copolymer rubber and an outer layer of rubber composition which comprises specified amounts of a selected class of sulfurs, organic peroxide and triazine compounds combined with selected sulfur-curable base rubbers.

Abstract: Rubber compositions are disclosed which are tailored to exhibit high adhesion to brass, sufficient resistance to heat and to oil and great elasticity. A selected class of highly hydrogenated acrylonitrile copolymer rubbers are blended with specified amounts of a selected class of trially isocyanurate compounds, organic sulfur-containing compounds or sulfur donors and organic peroxides. Also disclosed is a hose built with an inner tube formed from the above rubber composition and a reinforcing layer from a pressure-resistant, metallic wire plated with brass.

Abstract: A multi-layer tube suitable for use on motor vehicles composed of a cylindrical wall having an outer surface, and an inner surface essentially parallel to the outer surface. The cylindrical wall has a first region having an essentially uniform cross-sectional diameter and a second region which has a cross-sectional diameter differing from the essentially uniform cross-sectional diameter of the first region. The second region has at least one convolution contiguously adjacent to the cylindrical wall of the first region.