US 2941915 A
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Description (OCR text may contain errors)
June 21, 1960 F. w. MANNING METHOD oF 'MAKING REINFORCED COMPOSITE PIPE 2 Sheets-Sheet l Filed Dec.
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June 2l, 1960 F. w. MANNING 'mon oF MAKING REINFORCED COMPOSITE PIPE;
2 Sheets-Sheet 2 Filed Dec. 28, 1954 United States Patent METHOD OF MAKING REINFORCED CMPOSITE PIPE Fred W. Manning, P.0. Box 125, Palo Alto, Calif.
Filed Dec. 28, 1954, Ser. No. 478,047
6 Claims. (Cl. 154-83) My invention relates to hollow structures, such as standards for electric lighting fixtures, parking meters, etc.; more particularly it relates to piping and tubing, and methods and apparatus for their construction. This application is a continuation-in-part of my copending applications, Serial Nos. 384,882, and 444,510, filed October 8, 1953, and July 20, 1954, respectively, now Patent Nos. 2,750,317 and 2,749,965, respectively.
It has been the practice heretofore to form reinforced plastic pipe by winding continuous filaments or tapes about a mandrel, coating and bonding the windings by a suitable resin to form a pipe of the required diameter, curing the pipe, and removingit from the mandrel, all in separate operations.l
'Ihe primary purpose of the present invention is to combine the several operations of prior practice to produce light weight plastic pipe reinforced by stretchoriented discontinuous filaments of substantial length and strength in one continuous operation.
A further object is to provide a method and apparatus for producing light weight reinforced plastic pipe in either rigid or flexible form.
Other objects will become apparent from the following description.
In accordance with one aspect of my invention, the reinforcing fibre-forming material is forced o`r fiows from an extrusion device, melting furnace, or other feeding device, in finely divided portions, threads, or streams onto the periphery of a rotor which is preferably coated with or enclosed by an antiadhesive material, such as polytetrauoroethylene. The movement of the rotor brings discrete solids held in the pockets of its peripheral Wall into adherent contact with the fibre-forming portions. The latter are then preferably pulled a predetermined distance and attenuated into laments before the solids are blasted from the pockets through a stretching and directing barrel.
The fibre-forming streams are in an adhesive` condition at the time of contact is made with the discrete solids. The temperature and force of the propulsion fiuid are such that the solids, upon being propelled from the rotor, attenuate the comparatively short length adhesive fil aments into filaments of substantial length and strength compared with filaments normally produced by force of elastic fluid streams without the aid of pulling solids.
The filaments may be only a few inches in length for a short length barrel and a close-up depositing surface, or they may be many feet in length for the usual length of barrel, or they may be continuous. The propulsion fluid temperature may be atmospheric for cold-drawn laments, or it may be the adhesive temperature of the filaments if the latter are to be deposited in an adhesive condition. The propelling fiuid pressure may be the few ounces per square inch used in an ordinary blowing machine, or it may be 50 to 100 lbs. or more per square inch when the solidsv are to be propelled great distances, as when a web is to be spun over a fruit tree.
Stretch-orientation of a filament ordinarily commences y 2,941,915 Patented June 21, 1960 ice at the moment a filament can be sufficiently tensioned to assume a substantially straight line between horizontal holding and pulling means without the aid of suppott between the two said means. This may be at the moment it leaves the extrusion device, and for sometime thereafter the filament may continue to be in a plastic and an adhesive condition, as indicated by the distance usually maintained betweena spinneretand the first windup bobbin to prevent sticking of adjacent filaments; and so long as a filament is maintained inthis'- plastic and adhesive condition, or is attached to a source` of supply in this plastic and adhesive condition,v the filament or source of supply may be drawn out indefinitely. Honrever, once the filament has become set, additional stretching will usually bring it to its initial point of elasticity, and from there until its elastic limit has been reached it may be truly elastic, returning to its initial point of elasticity when the stretching force has been' removed.
Therefore, if the entire length of a filament is colddrawn between a pulling pellet and a succeeding pellet and its elastic limit has been reached, the filament. will usually break at the succeeding pellets; if the inner end of a filament remains adhesively connected to a succeed ing pellet, or the former has not reached its elastic limi-t, the succeeding pellet can usually be shot from the rotor without any breakage in the filament, thus producing a continuous filament with adherent pellets spaced at regular intervals along its length. In other words,` propul sion temperatures, pressures and distances can be so r'egulated that a discontinuous filament can be produced if cold-drawn by a pellet beyond its maximum strength and elastic limit; a continuous filament can be produced if stretched by a pellet within its maximum strength and elastic limit, and the rotating mandrel on which the filament is deposited will function as a wind-up drum.-
To prevent adherence to the gun barrel of filaments or pellets during propulsion, the pellets are usually shot centrally through the barrel in a line that istangential to the peripheral movement of the rotor. The inside of the barrel can also be coated or lined with an antiadhesive enamel or tubing, such as polytetrauoroethylene. This will normally prevent adherence. However, if because of high temperature and/or pressure a finely divided portion of fibre-forming material is disrupted into a multitude of adhesive filaments and the filaments dispersed sufficiently to contact the sides of a barrel before exit therefrom, the barrel can also be protected by being shortened as much as is necessary and an ejector placed thereover. The' propulsion of an annular column of higher pressure duid through the ejector barrel will' prevent adherence of filaments or pellets to either barrel, even without the above lining. Obviously, the length of the barrels will vary within wide limits depending mostly upon their diameters which will be determined fromV the volume of pellets to be shot simultaneously therethrough.
If the filaments are cold-drawn by propulsion pellets of lower softening temperature than the filaments, both are then calendered at a temperature and pressure lat which the pellets are fluid and adhesive but below the softening point of the filaments, i.e., point atA which they begin to lose their stretch-orientation. The pellets should be of uniform'siZe and carefully proportioned to the weight of the fibre-forming material, and may be almost anything up to percent of theweig/ht of the filaments, or they may Weigh many times the latter, depending upon the material used and the purpose for which the pipe is required. The filaments will usually vary between lO microns and one mil in diameter, but may be even finer or coarser than these figures indicate.
In yaccordance with another aspect of my invention, if an, inorganic material, such as glass, is to be used for reinforcing purposes, it can |be deposited in fibre-forming uid and adhesive portions on the peripheral surface of a. primary member moving through an endless circuit. Simultaneously discrete pulling solids are deposited on an adjacent peripheral surface of a secondary member, also moving through `an endless circuit. The converging and diverging paths of the two surfaces result in contact being made between the glass portions and the pulling solids, and the glass portions being attenuated into lilaments of predetermined length. The solids are then propelled by force of a fluid stream t-o increase the attenuation of the filaments.
Sometimes, however, it is desirable to deposit the glass or other bre-forming material on a primary member in discrete solid portions, and reduce the solid portions to fibre-forming iiuid and adhesive portions before contact Vwith the pulling solids, or by contact with heated pulling solids. The filaments then produced4 by propulsion of the solids can 1be deposited in an -`adhesive" condition on a rapidly revolving mandrel and the solids will be bonded by the iilaments It the filaments are stretched and deposited at a temperature below that at which they are connect with radial openings 7 in the inner ring, and the said openings connect through suction and pressure ports 8 and 9 respectively, with suction and pressure pipe connections 10 and 11, respectively.
The lower part of the casing forms a hopper 12 for the pulling pellets 13; and the former is equipped with an air inlet 14, check valve 15, check valve cage 16, and flexible strips 17 to prevent removal of air from the upper part of the casing.. The top of the latter forms a gun barrel 18 whose longitudinal axis is tangential -with the periphery of the rotor. The inner end' of the barrel encloses the outer end of an extruding device 19, described in my U.S. Patent No. 2,437,263, through which the adhesive, ,they and the solids can be bonded by `a vinyl,
phenol-formaldehyde, polyester, or' other resin. In any event, such a resin can be used to coat and impregnate the cylindrical web of solids and filaments, and the web then subjected to calendering and quenching to cure a thermoplastic resin, or calendering Iand heating to set a thermosetting resin.
The rotation of the mandrel with the relative axial 4 movement of the windings thereover result in the windings being built up that intersect or cross at an acute angle with one another in both spiral and helical direc` tions, but not in regular parallel lines unless the filaments retain their continuity between the feeding device for the fibre-forming material and the mandrel. The -relative axial movement may result simply from the movement of the windings along Itheir mandrel as the pipe is formed, or in addition to the said movement there may be a simultaneous reciprocating relative movement of the mandrel and the spinning gun. Of course, when a conical structure is being built, such as sometimes required for standards to support street lighting fixtures, there will, as `a rule, be no relative axial movement of the deposited windings over their conical supporting structure.
The invention is exemplified in the following description and preferred arrangements are illustrated by way of examples in the accompanying drawings, in which:
Fig. 1 is a vertical section of a spinning apparatus with cross section of a pipe forming device taken on line 1--1 of Fig. 2.
Fig. 2 is a longitudinal section of the pipe forming device shown in Fig. 1.
Fig. 3 is a modication of the pipe forming device shown in Fig. 1.
Fig. 4 is a cross section of the filament stretching barrel taken on line 4 4 of Fig. l. I
Fig. S is a vertical section of a modified form of spinning apparatus with cross section of the pipe forming device taken on line 5-5 of Fig. 6.
Fig. 6 is a longitudinal section of the pipe forming device shown in Fig. 5.
Fig. .7 is a cross section of the grooved collar taken tates about a shaft 3 which is maintained in a stationary position by the side walls of the casing 4. The outer ring equipped with pockets 5 and passages V6 which fibre-forming material 20 is extruded in finely divided streams by pistons 21 as the material is brought to fluidity by heating coils 22, and these extruded streams are attenuated into filaments 23 by pull of the pellets. Brackets 24 and pins 2S, attached to the casing, take the rollers 26 which ride on rails 27; and -also attached to the casing is ya bracket 28 to be connected to the operating cylinder described below. Hub 29 of the rotor extends through the side wall of the casing and is driven by a belt from a source of power not shown.
Fig. 2 shows a pipe forming device which is particularly suitable for producing exible pipe. A bed or baseplate 30 supports a winding shaft 31 which is annular for the greater part of its length, and to its open end is attached a swing joint 32 and pipe connection 33 to a source of suction for introduction of a treating fluid which Ifinally escapes through openings 34. Axially grooved collar `35 and circumferentially beaded collar 36 are rigidly attached to the inner end of the shaft, and to the beaded collar is attached the supporting pipe 37, the shaft being rotated by gear 38. Enclosing the shaft and driven by gear 39 is a perforated feeding sleeve 40 whose exterior threads 41 cooperate with the interior threads 42 of the gear `43 to helically groove the plastic pipe 44 and move it along the perforated supporting sleeve 45, `driven by gear 46, as the pipe is formed thereon. Ihe calender roll 47 is equipped with helical rings 48, rotates in bearings `49 and 50, is enclosed in casing 51, `and driven by 'gear 152. The pipe, after being helically grooved and the grooves shoved together, is subjected to heat in casing 53 from lamps 54, orto a temperature regulating fluid that enters and leaves through connections 55 and 56, respectively. During the curing period the pipe is supported by the stuingbox 57 and gland 58, which may also aid the feeding threads 41 and 42) in shoving the helical grooves together.
Figs. 3 and 4 show a modified arrangement of the pipe forming apparatus in which the mandrel, calender roll, and suction outlet 59 are all in axial alignment with the filament stretching barrel. Angle iron ring 60 and cover plate 61 attached to the barrel prevent -ingress of air around the barrel while the conveying uids from the barrel `are being exhausted through the outlet.
Fig. 5 shows ya modified form of a spinning gun particular-1y suitable for the spinning of glass fibres. In this arrangement discrete fibres 70 are conveyed by an endless belt 71 over a roll 72 and deposited in a uniformly distributed condition on the periphery of a foraminous Vdrum or rotor 73. This drum, which is in rolling contact with the lower rotor, rotates about the stationary arms 74, 7S, 76, and 77, held in fixed position between the sidewalls of the housing, thereby forming a neutral chamber 78 having no connections; suction chambers 79 and 8G, the former having a connection 81 to a source of suction, and the two being connected by an opening 82 in the arm 75; and a blowing chamber 83 having a connection 84 to a source of uid pressure.
The lower rotor 85 is driven by shaft 86 from a source of power not shown, and is equipped onits peripheral surface with uniformly spaced pockets or reservoirs for the filament forming material 87. This latter is first introduced into'hopper 88 in discrete and -nely divided portions, as from 50 to 200 mesh. The rateI of feed of this material is regulated by rotary valve 89 at the entrance to the feed pipe 90, and the material is then dispersed and delivered in fibre-forming uidity against the periphery of the rotor by a blast from the burner 91, which is supplied by fuel and yair under pressure through pipe 92 from a source of supply not shown. A scraper 93, pressured by a spring 94, removes excess from the surface of the rotor and the drip escapes through the `drain 95 in the refractory wall 96 andsteel casing 97. When the peripheries of the rotors enter diverging paths, short discontinuous filaments 98 are formed which are attenuated into long discontinuous filaments 99 when the fibres connected at its outer end are blasted from that portion of the foraminous drum passing over the pressure chamber 83. A jet ame 100 may be used to sever the inner ends of the filaments, if the pull on the latter does not completely empty the pockets of their fibre-forming material.
Figs. 6 and 7 show the modified pipe forming device indicated by cross section in Fig. 5. The bed or baseplate 101 supports the winding mandrel which consists of an annular shaft 102 equipped with peripheral openings 103. The shaft is driven by gear 104 and enclosed by a perforated supporting sleeve 105, the latter being driven by gear 106. Rigidly attached to the inner end of the shaft are the helically grooved collar 107 (Fig. 7) and the circumferentially beaded collar 108, and into the open end `of the shaft is screwed a plug 109 to which is connected swing joint 110 and pipe line 111 for entrance of steam or other treating fluid.
The reinforrned plastic pipe 112 is moved along the mandrel sleeve as formed by means of a helical thread 113 on the primary calender roll 114, the latter being driven by gear 115; and cooperating with the calender thread is the internal thread 116 of the gear 117. The primary calender roll is supported by bearings 118 and 119, and secondary calender roll 120 by bearings 121 and 122. After passing between the secondary roll and the beaded collar, the plastic pipe is supported internally by the sleeve 123 attached to the annular shaft, and externally by stuffing-box 124 and gland 125. Casing 12'6 encloses the forward end of the plastic pipe, and its temperature is regulated by infra-red ray lamps 127, or a treating fiuid that enters and leaves the casing through pipe connections 128 and 129, respectively. Wheels 130 are attached to shafts 131 which pass through front and rear bearings 132 and 133, respectively, in the baseplate, and travel on rails 134. A lug 135 is suitably connected to the bed for connection to a piston rod.
Fig. 8 shows a hydraulic cylinder 136 which is bolted to the fiooring in fixed position. It is equipped With a two-way rotary valve 137 having pipe connections 13S, 139, 140, and 141, to pump, reservoir, and to opposite ends of the cylinder, respectively; and a lever 142. The piston rod 143 is connected to thel baseplate lugby n ut 144; and pins 145, suitably positioned in the baseplate, reverse the valve lever whenever the piston rod has reached the end of its travel.
The operation of the apparatus vdescribed above has been indicated in part in connection with the foregoing description. The following examples will more completely illustrate the methods that can be used in the practice of my invention.
Example I Flexible 6 inch diameter pipe is produced from wholly organic materials, such as polyamide filaments and poly ethylene pellets, as indicated in Figs. 1 and 2.
Passage of air through hopper 12, pockets 5, air passages 6 and 7, port 8, and suction outlet 10, results in one or more polyethylene pellets about 1A; inch in diameter filling each pocket as the periphery of the rotor passes over hopper 12. The passages 6 are smaller than the' pellets, and'consequently thelatter are held inthe pockets under. a diiferential pressure as long asthe pasd sages are connected to the suction port 8. Polyamide material having a molecular weight of about 20,000 is brought to fibre-forming uidity at 300 F. by coils 22 andv extruded in finely divided adhesive streams 20 by the pistons 21. Extrusion is tangential to the movement of the periphery of a rotor 18 inches in diameter, rotating at 5 to l0 r.p.m., and rotation of the latter resultsl in contact being madey at a temperature of about 300 F. between a fiuid stream and a pellet, or a plurality of streams and an axial row of pellets. Adherence between a stream and a pellet and a lesser adherence betweenthe stream and the polytetrailuoroethylene liner 1, resultsr in a positive pulling or stretching of a stream 20 into a filament 23.
The attenuation of a fluid stream 20 into a filament by positive pull of a pellet, with or without adherence of the stream to the periphery of the pocket liner, is continued until a pellet pocket passage opens to port 9 and pressure connection 11, whereupon the pellet is propelled from its pocket by a blast of air at room temperature and l0 lbs. pressure. This cold-draws the filament and strips it from the periphery arc of the liner back to the next pellet at which point the elastic limit of the filament will have been reached and it will break, providing the pellet has been shot a reasonable distance, as for instance, ten to twenty feet for a filament 1/32 inch diameter at its point of Contact with a pellet conveyed in a pocket spaced about 4.5 inches from a succeeding pocket. Or if a filament has not reached its elastic limit, or at least a portion of it has been maintained in an adhesive condition by using steam -or other propulsion fluid at a temperature of 300 F., a string of pellets can be propelled through the gun barrel in a continuous succession, uniformly spaced on unbroken fila ments, the conveying fiuid' escaping through suction outlet 59. Size of fibre stream, temperature and pressure 'of propulsion fluid, and distance the pellets are propelled may all vary within wide limits to give continuous or discontinuous filaments.
Propulsion of the pellets through the gun barrel results in the former being deposited on the foraminous supporting sleeve 45 which has a rotative speed of about 20 r.p.m. and is maintained at a temperature of 200 F. by steam entering shaft 31 through the swing joint 32 from pipe vconnection 33 and passing through the perforations of the shaft, pullingI sleeve, and supporting sleeve. At thisv temperature the polyamide filaments lose none of their stretch-orientation, and the rapid rotation of their supporting sleeve with back and forth movement of gun on rails 27 results in the filaments being deposited uniformly and in both spiral and helical coils about the sleeve with the filaments crossing one another at an acute angle. But the temperature of 200 softens the pellets, and rotation of the calender roll 47 results in a uniform spread of the pellets over and in the interstice's of the filamentary web to form a smooth surface pipe which is nonadherent to either roll or sleeve due to their coating with an antiadhesive, such as polytetrauoroethylene. The left hand or rear portion of the supporting sleeve where the first thin shell of pipe is formed is imperforated, and there will be no tendency for vthe uid pellets under calender pressure to enter the forward perforations.
The to-and-fro movement of the spinning gun across the length of the calender roll can be obtained by 'any ordinary fluid (steam, air, water, etc.) operated cylinder actuated by a rotary valve, all of which is well known to those versed in the art. In the present case, the cylinder 136 (Fig. 8) is bolted to the iioor and its piston rod is attached by nut 144 to the bracket'28 of the rotor casing. Fluid from a pump connnection 138 enters valve 137 and is forced to opposed ends of the cylinder alternately through pipe connections and 141. The returnof the iiuid, if liquid, to its reservoir is through whenever the piston rod has reached the end of its stroke. y
The travel of the plastic pipe along its supporting sleeve as the former is built thereupon is accomplished by the pull of the internal thread l42 of the gear 43 and the external thread 41 of the feeding sleeve 40, the two threads or helices being displaced in respect to each other to the extent of one-half their pitch, and decrease in this pitch and tightening of the packing in stuing-box will aid in shoving the grooved helices of the plastic pipe closer together. `The forward movement of the plastic pipe may also be aided by the helical thread 113 of the calender roll and steam pressure passing through the perforations of the shaft, pulling sleeve, and supporting sleeve. Axially grooved collar 35 (somewhat similar to 107 in Fig. 7) prevents turning of the plastic pipe on its supporting sleeve, and the collars circumferential beaded portions removes any ridges made by the axial grooves. Curing of the plastic pipe is accomplished by passing air at zero temperature through the casing 53 from inlet connection 55 to the outlet connection 56.
Obviously, the pulling sleeve l40 with exterior thread 41 must turn at the same speed as the interior thread 42 of the gear 43, and the speed of these threads must be greater than the speed of the supporting sleeve, if both rotate in the same direction, in order to pull the plastic pipe along the latter; and the speed of the axial grooved collar `35, and annular shaft 31 to which it is aflixed, should be the same as the supporting sleeve 45 if the plastic pipe is to move forward without turning on the said sleeve.
Example Il Organic ilaments and inorganic pulling solids can be utilized in much the same way to produce flexible pipe. In this example, polyamide filaments are pulled by chopped glass strands from one-half inch to two inches in length in the same manner as described above for polyethylene pulling solids.
Upon deposition over the mandrel, the glass fibres and polyamide filaments are impregnated and coated by a polyester resin from spray 146 (Fig. 5) at a temperature below the softening point of the filaments, the weight of the resin usually varying between and 40 percent of the weight of the pipe. The impregnated pipe is calendered as it is moved along the mandrel, and radiant heat at a temperature of about 200 F. from the lamps 54 sets the resin as the pipe moves through casing 53.
Obviously, asbestos, micaceous mineral, and the like can also be used as pulling solids; also other resins, such as vinyl-chloride-acetate can be used for coating purposes, and cooling fluids used for setting purposes.
Example III Wholly inorganic materials, such as glass and asbestos, can be used in somewhat similar manner to produce rigid pipe, as -indicated in Figs. 5 and 6. The arrangement for spinning glass is similar to that described in the above mentioned Patent No. 2,750,317.
Asbestos -iibres 70 are conveyedon a belt 71 and uniformly distributed over a rotor consisting of a foraminous drum 73 of 100 mesh, which rotates about stationary arms 74, 75, 76, and 77. These arms enclose suction chambers 79 and S0, and thereby maintain the bres on the periphery of the drum until blasted therefrom by heated air or steam pressure from chamber 83.
Small, discrete particles of nbre-forming glass 87, such as from l00 to 200 mesh, are charged into the hopper 88 and fed as required by rotary valve 89 through pipe 90 to the burner 91, which is supplied by fuel under pressure by pipe 92 from a source not shown. The blast of burning fuel reduces the discrete particlesof glass to a libre-forming fluidity at a temperature of about 1900- F., and in that condition they are deposited on the peripheral surface and in the pockets of rotor or the particles, if deposited in a solid condition, will adhere to and be reduced to libre-forming iluidity by the rotor heated to about 2100u F. from a jet flame or other suitable means. The molten glass in either case is scraped by a spring pressured blade 93 into the pockets and the excess is removed entirely from the rotor and drained through outlet 95.
Converging paths of the two rotors bringI the discrete asbestos bres and the pockets filled with fibre-forming glass material into adhesive contact, and their diverging paths cause the glass in their respective reservoirs to neck down into positively stretched filaments 98 until iinally the fibres are cut off from their suction Contact with the peripheral surface of the primary rotor and blasted therefrom by heated air or steam pressure within the pressure chamber 83. The blast gives the fibres a theoretical initial velocity of at least 10,000 feet per minute and the pull exerted by the fibres to which the filaments 9S are adhesively connected, produce lilaments `99 from 2 to 20 feet in length.
The operation of the pipe production apparatus is much the same as that described in Example 1, with the following exceptions: the plastic pipe is moved along its supporting sleeve by means of the exterior helical thread 113 on calender roll 114 aided by interior helical thread 116 of the gear 117 and interior steam pressure from shaft 102; and the peripheral travel of these threaded surfaces Will ordinarily be greater than that of the supporting sleeve, if they rotate in the same direction, to move the plastic pipe forward. Helically grooved collar 107 permits a limited amount of turning of the plastic pipe during such movement, and this also aids the forward movement. The markings or ridges left by the feeding threads and grooves are removed by the secondary calender roll 120 and the circumferentially beaded collar 108. The glass filaments and asbestos bres are impregnated and bonded by a polyester resin from a series of sprays 146 within the casing 51, similar to that in Fig. 2, and the pipe is cured by radiant heat from lamps 127 within casing 126.
In the above examples the blast from the spinning rotor is exhausted from Vcasing 51 by suction'outlet 59, and entrance of air to the casing from other sources is prevented-by closure plate 61. This plate moves in close contact wit-h the entrance of the casing and extends sufficiently therebeyond to form a closure during the relative axial movement of the gun and pipe-forming device. The arrangement shown in Figs. 3 and 4 for equal distribution of the conveying fluid around the pipe-forming device will usually result in the iilaments being deposited more uniformly about the mandrel.
It is obvious from the above examples that a libreforming material can be deposited on a retaining wall in discrete portions, or as a lm or threads connected to a source of supply, and the wall moved to bring the material and discrete pulling solids into adherent contact. Convers-ely, the solids can be deposited 0n a retaining wall in spaced portions or -uniformly distributed condition, and the wall moved to bring the solids and fibre-forming material into adherent contact. In any event the libre-forming material must be sufficient-ly adhesive to adhere to the fibre-.forming material, during propulsion of the solids.
yIt will furthermore be evident that puliing solids can be so regulated as to size and spacing on a retaining wall, and the distances and directions they are to be propelled from the wall so controlled, that they can be deposited with great `uniformity and spacing, and the filaments will have a predetermined stretch; and when thermoplastic pellets are subjected to heat and pressure to bond a filamentary web to a cylindrical web to be reinforced, the pellets can be calendered and thinned out to produce an impervious coating over, and/or fill the interstices of, the reinforcing web.
It will also be evident that laments and pulling solids can be deposited over the periphery of a mandrel without one being used to bond the other, and suction through the mandrel and swivel joint connections used to aid the said deposition to form a pervious cylindrical wall for a pipe or other struct-ure. The wall can then be impregnated and coated with a polyester or other suitable resin and calendered to make it impervious. And by siutable regulation of temperatures and materials, the filaments can be bonded by pulling solids without loss of stretchorientation to the filaments; or the solids can be bonded by the filaments without loss of stretch-orientation to the latter, if either or both are coated with a non-solvent adhesive by ejector in the stretching barrel or spray after deposition.
lIt will again be evident that the inorganic materials of Example vII=I can be used to -produce the flexible pipe of Examples II and II; also, the organic materials of Example I, or organic and inorganic materials of Example IfI, can 'be used to produce the rigid type of Example III. In similar manner, other breforming materials in molten, solution, or other condition, can be used to produce either rigid or flexible pipe. It' solvents are used to reduce `fibre-forming materials to fluidity, a portion will evaporate under heat from the mandrel in the pipe deposition chamber and be carried off through outlet 59, and the balance will be evaporated in the setting chamber and carried oi through outlet 56 in `Fig. 2, or outlet 129 in Fig. 6.
It will be understood throughout the specication and appended claims that a spiral is one Whose successive coils circle around a center and gradually recede therefrom, or approach thereto; a helix is one whose successive coils extend axially, as in an ordinary screw thread; and glass is used in a generic sense to include glass and mineral wool compositions, and the like.
I claim as my invention:
1. In a method for making pipe, the steps comprising: dispersing a bre-forming material in a heated gaseous atmosphere to produce discrete fluid particles; depositing the said particles on a primary rotating member to form a coating thereover of fibre-.forming uidity; adhesively contacting predetermined portions of the said coating with discrete solids; propelling the said solids by force of a huid stream movin-g in a controlled path to attenuate the said portions into solids-entrained, stretch-oriented filaments; depositing the said laments in a successive series of superposed windings about a secondary rotating member by relative movements of the windings in said controlled path and the said secondary member; and bonding `the said solids and windings together to form the wall of the said pipe.
2. The method of claim l for making pipe, including the step of calendering the said wall during the said relative movements to consolidate the said iilaments and solids and extend the said bonding throughout the said wall.
3. The method of claim 1 for making pipe in which the said filaments are built up in spiral and helical windings with the said solids uniformly distributed therethrough.
4. The method of claim 1 for making pipe, including the step of applying tractive yforce to the said wall to move Y the Wall axially along the said secondary member as the said windings are built in superposed layers thereupon.
5. The method of claim 4 for making exible pipe, and including the steps: Ihelically grooving the said pipe; compressing the helical grooves axially; and applying heat to set the said grooves during the movement of said wall.
6. r[The method of claim 5 for making exible pipe in which all the said steps are successive and continuous.
References Cited in the le of this patent UNITED STATES PATENTS