MXPA96004640A - Method for the formation of better construction pipe - Google Patents

Abstract

The present invention relates to a method of forming plastic tubing having an improved construction comprising the steps of: having a flow of hot plastic through a die and subsequently being extruded through a die head to form a component of extruded wall having first and second end walls, the die head has formed therein a plurality of first dimensioned spaces and a plurality of second dimensioned spaces, the second dimensioned spaces have an opening located inside each of the second spaces dimensioned, the die is attached to a manifold assembly, the manifold assembly comprises sets of tubes located centrally to each other, each set of tubes comprises a water inlet tube, a tube through which a vacuum is drawn, and a tube of water return, each of the sets is placed longitudinally inside a manifold tube of d With the outermost surface of each set of tubes separated at a first distance from the respective die manifold tube, each of the respective die manifold tubes extends through the die, having air at a pressure on the scale of 29.57-59.14 milliliters of flow through the die head openings in the same direction as the plastic being extruded, having the plastic extruded on at least two calibration tips that are secured to the die, each of the extremities of calibration has a proximal portion adjacent to the head of the die, the proximal portion of each of the decalibration limbs is spaced a second distance from the die head, each of the calibration limbs has a first section having an external surface, the first section has: 1) at least one water receiver channel connected to the water inlet pipe, 2) a channel connected to the water inlet pipe, uo through which a vacuum is drawn, and 3) the water return pipe centrally positioned on the external surface of the first section, the first section having formed in the same openings connected to the channel connected to the tube through which extracts a vacuum, each of the calibration limbs has a second calibration end section having an external surface and an internal channel, the second section has the water return tube centrally positioned from the external surface of the second section, the distal end of the water return pipe extends beyond the distal end of the second section, the second section has formed therein openings connected to the inner channel, having water flow through the water receiving channel in a first direction, water flows through the first section to the second section and through the openings of the second section on the outer surface The vacuum of each of the second calibration end sections so as to flow between the outer surface of the second section and the extruded plastic, have a vacuum drawn through the respective tubes and channels in the manifold assembly, the vacuum is extracted the plastic extruded down on the outer surface of the first section of each of the calibration tips, and have the water elevation to a level within the extruded plastic that is above the far edge of the water return pipe so that the water flows into the water return pipe and flows through the manifold assembly in a second direction

Description

METHOD FOR THE TRAINING OF IMPROVED CONSTRUCTION PIPELINE Background of the Invention This invention relates generally to a method for forming an extruded plastic pipe and, more particularly, to a method for forming pipe of an improved construction. Plastic pipe has found a variety of uses especially in relation to drainage. One of the concerns in the manufacture of plastic pipe is the amount of raw materials consumed and the weight resulting from the finished product. For example, a solid wall plastic pipe with an internal diameter of 121.92 cm weighs approximately 296 kg / m. It has recently been discovered that plastic tubing having openings formed therein, when the tubing is seen in cross section, weighs approximately 44.4 kg / linear m. However, there is a problem in the manufacture of the pipe having the desired cross section. In general, extruded plastic pipe is formed on a production line that has a variety of specific machines incorporated into the manufacturing process. One of the first machines is an extruder. The plastic powder, or more preferably pellets, are fed through the extruder where they are subjected to high temperatures so that the plastic melts.

The plasticized plastic then proceeds through a feed tube, at the end of which the plastic enters into a drum shaped die typically. On the front of the die is the specific cross section profile to be extruded. As the hot plastic exits the die, it passes over what are called calibration tips or gauges or bales that help maintain the desired cross-sectional shape that has been extruded. These calibration tips are part of a manifold assembly. The rest of the manifold assembly extends from above the die as well as beyond the calibration limbs. In addition to the extruder and the die that is supported on a die post assembly, the plastic pipe is manufactured using a former or forming head. The prior art of pipe manufacturing has not been able to manufacture plastic pipe that, besides being aesthetically pleasing, has a cross section that incorporates openings. Although patents have described inventions in tubing having openings incorporated therein when the tubing is viewed in cross section, as a practical matter it has apparently been impossible to have manufactured the tubing. In contrast, when flowing through the die head, the hot plastic collides on the intended openings to be formed therein. Additionally, another problem in the attempt to manufacture the plastic pipe having said cross-section is that the hot plastic tends to get stuck as it leaves the die head and begins to flow on the bales.

It is evident therefore that there is a need for a method for manufacturing an aesthetically pleasing product having the desired cross section.

BRIEF DESCRIPTION OF THE INVENTION The problem associated with the above methods of plastic pipe manufacturing is overcome in accordance with the present invention by a method for manufacturing plastic pipe so that the pipe has openings formed therein when the pipe is viewed in cross section, comprising stages of having hot plastic flow through a die and subsequently being extruded through a die head to form an extruded wall component having first and second end walls, with the die head having formed therein a plurality of first dimensioned spaces and a plurality of second dimensioned spaces, with the second spaces' dimensioned having an opening located within each of the second dimensioned spaces. The die is secured to a manifold assembly, with the manifold assembly comprising sets of tubes located centrally to each other, each set of tubes comprising a water inlet pipe, a tube through which a vacuum is drawn, and a water return pipe. Each set of tubes is longitudinally positioned within a respective die manifold tube with the outermost surface of each set of tubes separated a first distance from the respective die manifold tube. Each of the respective die manifold tubes extends through the die. Another step in the process is to have air at a pressure in the range of 29.57-59.14 milliliters of flow through the die head openings in the same direction as the plastic being extruded. Still another step is to have the plastic extruded on at least two calibration limbs that are secured to the die, each of the calibration limbs having a proximal portion adjacent to the die head. The proximal portion of each of the calibration limbs is spaced a second distance from the die head. Each of the calibration limbs has a first section with an exterior surface, with the first section having: 1) at least one water receiver channel connected to the water inlet pipe; 2) a channel connected to the tube through which a vacuum is extracted; and 3) a water return pipe positioned centrally of the outer surface of the first section. The first section has formed in the same openings connected to the tube through which a vacuum is extracted. Each of the calibration limbs has a second calibration end section having an external surface and an internal channel, with the second section having a water return tube positioned centrally of the external surface of the second section. The distal end of the water return pipe extends beyond the distal end of the second section, with the second section having formed therein openings connected to the inner channel. An additional step is to have water flow through the water receiving channel in a first direction. The water flows through the first section and into the second section and from there through the openings of the second section on the external surface of each of the second calibration end sections to flow between the external surface of the second section and the extruded plastic. Another step in the process is to have a vacuum drawn through the respective tubes and channels in the manifold assembly, with the vacuum pulling the extruded plastic down on the outer surface of the first section of each of the calibration tips. Still another step is to have the water rising to a level within the extruded plastic, whose water weight is above the distal end of the water return pipe so that the water flows into the water return pipe and flows through the water. Multiple assembly in a second direction. The method also comprises the additional step of winding the extruded wall component until the first wall is adjacent to the wall. second wall and merge to it. The method also comprises the step of ventilating the manifold assembly to the atmosphere. The method also comprises the additional step of applying water to the external surface of the plastic after it has been extruded. A method for forming rolled plastic tubing having an improved construction comprising the steps of extruding the plastic through a die head on a plurality of calibration limbs, with each of the calibration limbs having flowing water is also described. through them both in a first and in a second direction and, a vacuum extracted, with the plastic when extruded forming a wall component having first and second end walls and a plurality of cavities of a first and second size and , simultaneously, causing the air to flow through the die head and into the cavities of the second size. An additional stage has a vacuum drawn through each of the calibration tips, with the channels formed at each calibration end extending to the outer surface of each calibration end. The vacuum draws the extruded plastic down on the outer surface of the calibration tip. Another stage has water flowing in the first direction of flow through the openings in the calibration and flow extremities between each external surface of the calibration end and the extruded plastic to cool the extruded plastic. Still another step includes winding the extruded wall component until the first end wall is directly adjacent to the second end wall. The first extreme wall is then fused with that one. Subsequently water is applied to the external surface of the plastic after it was extruded. The above method also includes the step of ventilating the manifold assembly to the atmosphere. It is the primary object of the present invention to provide an improved method for the manufacture of tubing that has an improved construction. Other objects and advantages of the invention will become apparent from the following description, the accompanying drawings and the appended claims.

Brief Description of the Drawings Fig. 1 is a side view of a die and a die post assembly with a manifold assembly secured thereto in an operative position for use in accordance with the method of the present invention. Fig. 2 is a front elevational view of a die and a die post assembly in which the die will extrude the wall of a plastic pipe having openings formed therein, specifically 8 apertures of generally small triangular shape as well as 3 openings of generally larger circular shape.

Fig. 3 is a side elevation view of the first more central calibration end section associated with the method of the present invention. Fig. 4 is a side elevational view of the intermediate tube which in the preferred embodiment of the invention is formed and then inserted into the first calibration end section shown in Figure 3. FIG. 5 is a vertical sectional view taken in FIG. a very enlarged scale along line 5-5 of Fig. 3, however, this particular view shows the first assembled calibration end section, thus describing both the outer shell as well as the presence of the tube intermediate. Fig. 5A is a vertical sectional view taken at a greatly enlarged scale and similar to Fig. 5, however, this particular view shows a first extreme end assembly section assembled. Fig. 5B is a vertical sectional view taken on a greatly enlarged scale and similar to Figs. 5 and 5A, however, this particular view shows the other first section of more extreme calibration end assembled. Fig. 6 is a perspective view on a greatly enlarged scale taken along the top of the die of FIG. 1 . Fig. 7 is a vertical cross-sectional view on a greatly enlarged scale taken along line 7-7 of FIG. 1 .

Fig. 8 is a vertical cross-sectional view on a greatly enlarged scale taken along line 8-8 of FIG. 1 .

Detailed description of the invention Referring to the drawings, attention is first directed to Fig. 1 describing the manifold assembly associated with the method of the present invention generally described with the number 10. The manifold assembly extends through the die 15. The drum-shaped die having first and second ends is supported on a die post assembly 20. The die and the die post are of the type found in the plastic extrusion manufacture. The preferred embodiment of this invention uses a side feed die, spiral feed, although a cross feed die may be used. Similarly, the improved manifold calibration limbs 16 are located where prior art calibration rounds or limbs had been placed ie at the second end of the die where the plastic is extruded therefrom. This space ratio can be better appreciated from a consideration of Fig. 2 which describes the presence of a die head 17. Die heads are well known in the conventional extrusion technique. However, this particular die head describes the presence of 8 small triangular sections and 3 larger circular sections. The circular sections or spaces are of a first size and, the sections or generally triangular spaces are of a second size. Both types of die spaces can also be referred to as die openings or die cuts. During the extrusion of the pipe wall, the plastic flows through the die head through those spaces or sections 17a and 17b respectively. Additionally, it will be noted that there are air vents 17c located near the center of each of the triangular shapes. The die head and limbs of calibration cooperate to form the extrusion of a pipe wall component having a plurality of openings formed therein when the pipe wall is viewed in cross-section. Extending through the die and the die head 17 is a portion of the die manifold assembly 10 to which the calibration limbs are physically secured. This portion of the die manifold assembly 10 is shown on the leftmost side of the die head 17 and extends some distance from the drum form die, as will be described below. On the rightmost side of the die head 17 is the calibration tip 16 associated with the manifold 10 shown in its complete assembly, as can be seen from a comparison with Figure 1. The calibration tip 16 associated with This method of the invention is formed by having a first section 25 and a second section 26. The first section or tubular member 25 is shown as being itself secured to the portion of the die manifold assembly 10 used in the method of this invention, whose portion passes through the die 15 in the central portion of the die head 17 in Fig. 2. The first tubular member 25 is formed, in the preferred embodiment of the invention having a tubular outer shell 27. As can best be appreciated from from a comparison of Figs. 2 with Figs. 3, 5 and 7, the tubular outer shell 27 has a first end as well as a second end, 28 and 29 respectively. Additionally, the outer shell 27 is formed having an outer surface 30 with this outer surface having therein formed a first radial groove 33. Shaped in the first radial groove is a plurality of first section openings 35. Additionally, a second radial groove 37 is formed having a plurality of second section openings 39 formed therein. The tubular outer shell is preferably formed having u? first end end 40, a end housing 42, and a second end end 44. These three parts are components of the tubular outer shell and are secured to each other by respective brass connecting rings 48. Each ring 48 is only a ring with a threaded outer surface engaging a portion of the inner surface of the end housing 42. A threaded portion of the inner surface of the first end end 40 also engages with the connecting ring 48, with the inner surface of the first extremity end being 52. A threaded portion of the inner surface of the second end extremity 44 also engages with the connecting ring 48, with that internal surface of the second extremity end being 53. It will be appreciated from Fig. 3 that the first extremity end is tapered towards the die head. This allows for an easier initial flow of the heated plastic over the calibration end 16 as the plastic exits the die head 17. In addition to the first radial groove 33 and the second radial groove 37, the outer surface 30 of the outer tubular housing 27 preferably also has a spiral groove 55 formed therein. It should also be noted that the spiral groove intersects both the first radial groove and the second radial groove. It will also be appreciated that from a comparison of Figs. 3 and 5 that the outer casing of the first section 25 of the most central tube assembly is preferably formed having two relatively flat surface portions 60 and two curved surface portions 62, considering that the two sets of tubes have only one flat surface with with respect to its internal side wall as can be seen in Figs. 5A and 5B respectively. The intermediate tube 64 shown in Fig. 4 also has a first end 65 and a second end 66 and an internal surface 68 as can be seen from FIG. 5 as well as an external surface 69 as can be seen from Figs. 4 and 5. A plurality of longitudinally extending channels 70 are generally formed on the outer surface 69 of the intermediate tube 64. In the pipe wall formed using the method of this invention, there are six such water receiving channels 70. As stated above, Fig. 5 shows a vertical cross-sectional view at a greatly increased scale where the intermediate tube is positioned to be encircled by the tubular outer shell 27. As such, it can be seen that the different water receiving channels 70 are enclosed so as to allow the water to pass in a first direction and towards the second direction. Preferably the flow rate is 15.12-18.9 liters of water per minute for each set of tubes. Additionally, the presence of cold water in the six channels helps to cool the outer tubular shell in the presence of hot plastic. As can be seen in Fig. 5, the first tubular member 25 also has a plurality of radially extending channels from the inner surface 72 which extend from the inner surface 68 of the intermediate tube 64 to the openings in any of the radial slots 33 or 37. As will be described below, the internal surfaces 64 of the intermediate tube 64 help define a channel through which a vacuum is drawn. In the current assembly of the first tubular member, the tubular outer casing has an intermediate tube placed therein, then the appropriate holes were drilled through the tubular outer casing and the intermediate tube. First, the tubular outer casing and the intermediate tube are welded, with the inner surface of the outer casing 27 being welded to the external surface 69. Once the two components are stabilized and a hole diameter of 0.238 cm is drilled. , an aluminum tube with an external diameter of 0.238 cm with a 0.158 cm hole fits under pressure into the 0.238 cm hole until it reaches the inner surface 68. This process is repeated until the desired number of channels exists, which was established before with reference to Fig. 5 is six. The upper portions of the tubes can exit one by one and each respective radially extending channel 72 is sealed in place with the appropriate sealant. Preferably the radial groove is placed on the outer casing after the aforementioned welding and drilling have occurred, but prior to the insertion of the tubes that cause the channels to extend radially 72. The end casing 42 is approximately 45.72. cm in length in the preferred embodiment of the invention and has an external diameter of approximately 6.35 cm. Preferably the center of the first radial groove is 6.35 cm from the junction of the first end end and the end housing. Meanwhile, the second radial groove is approximately 3.96 cm from the junction of the second extremity end and the limb casing. The spiral groove is 0.238 cm wide and has a double step edge of 2.54 over the total 45.72 cm. Similarly, the radial grooves are 0.238 cm. In addition, the different longitudinally extending channels 70 are formed having a radius of 0.793 cm. In addition each of the slots is formed being 0.635 cm from the high point of the radius. The intermediate tube is approximately 41.91 cm and has an external diameter that adjusts the internal diameter of the outer shell. Preferably both the outer shell and the intermediate tube are made of aluminum. As can be seen from a comparison of Figs. 1, 2, 7 and 8 the second tubular member 26, also made of aluminum, comprises a first end 80 and a second end 82 as well as an internal surface 84 and an external surface 86. The longitudinal shape of the second tubular member 26 corresponds to the shape of the plastic product that is manufactured. When, as here, the manufacturing system is designed to produce the circular plastic pipe, the longitudinal shape of the second section is curved. As can be seen in the drawings, the second tubular member 26 also has a plurality of openings 88 formed therein with those openings extending between the inner surface 84 and the outer surface 86 of the second tubular member 26. Therefore, it can be seen that the second end of the tubular outer shell 27 of the first tubular member 25 is fixed to the first end of curved member 80. It should also be noted that the first tubular member is of a first length and the second tubular member is of a second length with this second length being larger than the first length. For example, in the embodiment of the invention described herein, the second tubular member measures 106.68 cm in length with the first 7.62 cm being straight. Specifically, it should be appreciated that the diameter of the openings of the curved member is greater than the diameter of the openings of the first member, mainly because the openings of the curved member facilitate the flow of water therethrough while the openings of the first member They are used to facilitate vacuum extraction. The vacuum helps in stabilizing the shape of the plastic as it is extruded. The portion of the die manifold assembly 10 secured to the die 15 'can be better appreciated from a comparison of Figs. 6 and 7. As can be seen from these figures of the drawings, the first end of the die head or rear face 93 is secured thereto a rear multiple tube housing 95, this securing being achieved preferably by four screws In the current manufacture this rear multiple tube housing comprises three components 95a, 95b and 95c respectively. It will also be appreciated that the O-rings of the manifold tube housing 96a, 96b and 96c are positioned adjacent the rear manifold tube housing component. A TEFLON 98 insulating tube connects the inside of the die on the rear face of die 93 with a low-pressure air inlet line 99. The air entering the die through this line is finally fired at through the openings 17c in the die head and helps to cool the triangular plastic walls as well as to exert pressure outwardly on the plastic to support the cavity and consequently prevents its collapse. The pressure is approximately 29.5-59 milliliters. Furthermore, a water inlet line, with a tube for each manifold calibration limb is secured to the back manifold tube housing. This water inlet line 100 allows cold water to be introduced into the manifold assembly. A rear vacuum pipe 103 extends from the rear manifold tube housing 95 and connects to a rear vacuum line 105. Once again it will be appreciated that the number of subsequent vacuum pipes 103 and hence the number of lines Subsequent vacuum tubes 105 correspond to the number of calibration limbs 16. A water ejection pipe 108 also extends from the rear manifold tube housing 95 with each water discharge pipe 108 being connected to the first water line section. water ejection outlet 1 10. While the rear vacuum pipe and the water discharge pipe are preferably formed of metal, the rear vacuum line as well as the first section of the water discharge outlet line are of a plastic composition. Each of the first sections of the water ejection outlet line 1 10 connects to a water ejector 1 12. It has been found that a well ejector package sold by "Teel Water Systems" as a shallow well ejector Heavy duty works well enough to facilitate the removal of water through the manifold after circulation through it. The different water ejectors 1 12 are secured to a water ejector mounting plate 1 13 which is part of the die post assembly 20. To facilitate the operation of the water ejector 1 12, the ejection inlet lines of 1 15 are secured in the water ejector mounting plate to be secured to the water ejector 1 12. Similarly, the second water ejection outlet line sections 120 are secured in the mounting plate of the water ejector. water ejector towards the water ejector. In the current operation, the flow of water through the water inlet inlet lines 1 15 within the water ejectors 1 12 creates a Ventu ri effect which results in the formation of a vacuum which in turn it draws the water through the first sections of the respective water expelling line and subsequently expelled the water in a forced manner through the second section of the water expelling outlet line 120.

Even a better appreciation of the internal operations of the die manifold assembly 10 associated with the process of this invention can be appreciated from the consideration of Fig. 7 which shows a water ejection port 125 through which the water passes. as it is drawn through the calibration end and the manifold assembly secured and then flows through the first sections of the water expelling outlet line. The water enters the water ejection port 125 from the internal manifold tube 130 which is connected to the proximal end 92 of the second component 90. It will also be appreciated that within the manifold manifold housing component 95b there is a vacuum port. 135. The rear multiple tube housing component 95b is preferably welded to the vacuum tube 140. Similarly, the rear manifold tube housing 95c is preferably welded to the external manifold tube 150. As the housing component The rear manifold tube 95a is preferably screwed onto the internal manifold tube. The distal end of the vacuum tube 140 is held in frictional engagement by the inner surface 68 of the intermediate tube 64 of the first section 25. When the second component 90 is frictionally secured to the distal end of the internal manifold tube 130, the vacuum line the rear and the rear vacuum pipe 103 allow a vacuum to be drawn inwardly through the openings in the radial grooves. Each internal manifold tube 130, the vacuum tube 140 and the external manifold tube 150 are preferably made of stainless steel. Also shown is a water inlet port 145 through which water enters the rear multiple tube housing 95c through the water inlet line 100. The water then flows through the respective external manifold tubes 150. A housing connector 155 secures the multiple manifold tube housing to a mounting plate 160 which in turn is secured to the first die head end or back face 93 by appropriate fasteners 163. Therefore, according to the tube of multiple of die 165 extends through the die itself, has therein the external manifold tube 150 through which the cold water is flowing in a first direction, the vacuum tube 140 through which a vacuum is being drawn in the opposite direction for the water flow and, the internal manifold tube 130 through which the hot water is also drawn in that second direction subsequently exiting through the s water ejection lines. The outermost surface of each set of tubes 150, 140 and 130 respectively, with the outer surface of the tube 150 being in the preferred embodiment of the invention, a first distance from the respective die manifold tube being separated. Within the die manifold tube 165 is a preferably hexagonal shaped structure 175 which is positioned to assist in the support and stabilization of the external manifold tube 150. This minimizes also the heat transfer between the cooler tubes and the hottest This hexagonal structure 175 can be seen by being positioned adjacent the mandrel extension tube 185 of the die, which mandrel extension tube in turn is secured on the front face of the die head in the die head openings 187, which are preferably fork nut wrenches. The mandrel extension tube is screwed into a chuck extension component of the die, with the mandrel extension of the type known in the art. The space between the internal surface of the die manifold tube 165 and the external surface of the external manifold tube 150 forms a ventilation channel 152. Thus the method of this invention has the manifold assembly vented to the atmosphere by the cooperation of the ventilation channel 152, the ventilation channel outlet 153 and the enclosed common air space 154. Preferably the ventilation channel outlet is only a single opening in the first end of the die, although there would be three ventilation channels as in the multiple assembly mode shown in the drawings. In the meantime, the plurality of appropriate venting channels associated with each of the sets of tubes preferably converge near the rear internal portion of the die to form a common enclosed individual air space. More preferably, this enclosed common space is directly adjacent to the outlet of the ventilation channel.

It can be seen from the consideration of Fig. 7 that the proximal tip 40 and the die head 17 are separated at a second distance. Therefore, ventilation to the atmosphere extends from the space of approximately 0.317 cm between the proximal tip 40 and the die head 17 to the first end of the die with the portion of the ventilation channel between the die manifold tube and the outermost surface of each set of tubes being only 0.158 cm. In the current assembly, the die is assembled to encompass the portion of the manifold assembly shown and described with respect to Fig. 7. When it is finished, the leftmost portion of the die head is reassembled as shown. in Fig. 2. The first section 25 is then slid over the secured die manifold assembly 10. The threads of the first end 190 are then secured to the threaded terminal corresponding to the terminal end of the external die manifold tube. Helping to maintain a good seal are a first pair of O-rings 192 placed within the appropriate slots on the first inner end end surface 52 as shown in Fig. 7. The first tubular member is then positioned as shown in the middle of the die head 17. The second tubular member at its first end has a female quick release mechanism of the type well known in the pipeline art. In the preferred embodiment of the invention this quick release mechanism is a straight-line, bronze flow valve manufactured by "Parker-Hanifin", whose mechanism is attached to the quick release female mechanism 195 placed at the second end 66 of the intermediate tube 64. Therefore, when used in combination to form three circular openings through a pipe wall when viewed in cross section, the flat sections 60 on each of the calibration tips are parallel to a section. flat on an adjacent calibration tip. A second pair of O-rings 198 is located in the appropriate grooves on the internal surface 68. In relation to the current practice of the method of this invention, the presence of atmospheric ventilation is extremely important. Initially the machine does not use this feature and the hot plastic, in fact, was sucked into the space between the proximal end of the calibration tip and the die head where the extrusion operation jammed. The addition of atmospheric ventilation does more than remedy the situation. Instead of clogging, the plastic flowed easily on the outer surfaces of the calibration limbs. In addition, in the current use the cooling water passes through the water inlet tube 150 and the water receiving channels 70 within each manifold calibration end while a vacuum is drawn through the medium manifold tube 140 and through radially extending channels 72 in the first section. Still further, water flows from the water receiving channels within the second section 26 and subsequently through the openings 88 in the second tubular member on the external surface 86 of the calibration end. Water flows in this way between the outer surface of the second section and the extruded plastic surrounding the calibration end when the plastic is being extruded to cool the extruded plastic pipe. The water is deposited inside the cavity of the extruded plastic. Eventually the level of water within the cavity reaches the distal tip 89 of the flexible tube 90 where it is sucked through the interior of this second component 90, through the seal of the second component with the first component 130 preferably within the second section 26, through the water return tube or the first component 130 surrounded by the die and finally through the respective tube that connects the outlet of the water return tube with the water ejector 1 12. The method of this invention it also has the plastic wall component wound around a machine known as a former until the first end wall of the wall component is directly adjacent to the second end wall of the wall component. After the wall component leaves the die head, a side wall guide cooled with water, preferably made of aluminum and secured to the former, stabilizes the first end wall upon cooling. A ceramic heater attached to the die post assembly heats, or more accurately overheats, the second end wall. Adjacent wall components have their respective end walls fused together. As the end walls fuse together, preferably three TEFLON rolls wind the seam downward. To further assist in the cooling of the plastic pipe as it is wound around the former, the method includes the additional step of applying water to the outer surface of the now tubular plastic pipe. Preferably at least one cloth and, more preferably, two cloths folded over the pipe act to spread the water on the surface of the pipe to effect cooling. Preferably also at least one cloth is folded over the pipe to aid in the drying of the pipe surface. From the above detailed description of the method of the present invention it will be readily apparent that an extremely original method is provided for the formation of plastic tubing of an improved construction. Insofar as the method described herein constitutes the preferred embodiment of the invention, it is understood that the invention is not limited to this precise method and that changes can be made therein without departing from the scope of the invention which is defined in the appended claims.

Claims (6)

1. CLAIMS 1 . A method of forming plastic tubing having an improved construction comprising the steps of: having hot plastic flow through a die and subsequently being extruded through a die head to form an extruded wall component having first and second end walls, the die head having formed therein a plurality of first dimensioned spaces and a plurality of second dimensioned spaces, said second dimensioned spaces having an opening located within each of said second dimensioned spaces, the die secured to a manifold assembly which comprises sets of tubes located centrally to each other, each set of tubes comprising a water inlet pipe, a tube through which a vacuum is drawn and, a water return pipe, each set placed longitudinally inside of a respective die manifold tube with the outermost surface of each joint of tubes separated at a first distance from the respective die manifold tube, each of the respective die manifold tubes extending through the die, having air at a pressure in the range of 29.57-59.14 milliliters of flow through of the die head openings in the same direction as the plastic being extruded, having the plastic extruded on at least two calibration limbs that are secured to the die, each of the calibration tips having a proximal portion adjacent to the die. the die head, the proximal portion of each of the calibration limbs being separated a second distance from the die head, each of the calibration limbs having a first section having an external surface, the first section having: ) at least one water receiver channel connected to the water inlet pipe; 2) a channel connected to said tube through which a vacuum is extracted; and 3) the water return pipe positioned centrally of the external surface of the first section, the first section having formed in the same openings connected to the channel connected to the tube through which a vacuum is extracted, each of the extremities of calibration having a second end section of calibration having an external surface and an internal channel, said second section having the water return pipe positioned centrally of the external surface of the second section with the distal end of the water return pipe extending beyond the distal end of the second section, the second section having formed therein openings connected to the inner channel, having water flow through the water receiving channel in a first direction, said water flowing through the first direction and inside the second section and from there through the openings of the second section on the outer surface Each of the second calibration end sections to flow between the outer surface of the second section and the extruded plastic, have a vacuum drawn through the respective tubes and channels in the manifold assembly, said vacuum extracting the plastic extruded down on the outer surface of the first section of each of the calibration limbs, and have the elevation of water to a level within the extruded plastic that is above the far edge of the water return tube so that the Water flows into the water return pipe and flows through the manifold assembly in a second direction.
2. 2. The method according to claim 1, comprising the further step of winding the extruded wall component until the first wall is adjacent to the second wall and merges therein.
3. 3. The method according to claim 1, which includes the step of ventilating the manifold assembly to the atmosphere.
4. 4. The method according to claim 1, which includes the step of applying water to the external surface of the plastic after it was extruded.
5. A method for the formation of plastic tubing having an improved construction comprising the steps of: extruding plastic through a die head on a plurality of calibration limbs, each of the calibration limbs having water flowing to through them both in a first and in a second direction and, an extracted vacuum, the plastic when extruded forming a wall component having first and second end walls and a plurality of cavities of a first and second sizes, causing simultaneously that the air flows through the die head and into the cavities of said second size, having a vacuum drawn through each of the calibration limbs with the channels formed at each calibration end that extend towards the surface external of each calibration end, said vacuum extracting the extruded plastic down on the surface and Xterna of the calibration tip, have the water flowing in the first direction through the openings in the calibration tips and flowing between each external surface of calibration end and the extruded plastic to cool the extruded plastic, roll the component of extruded wall until the first end wall is directly adjacent to the second end wall and fuse the first end wall thereto, and apply water to the external surface of the plastic after it is extruded.
6. 6. The method according to claim 5, which includes the step of ventilating the manifold assembly to the atmosphere. SUMMARY A method for manufacturing a plastic pipe so that the pipe has openings formed therein when viewing the pipe in cross section, comprising the steps of having hot plastic flow through a die and subsequently being extruded through the pipe. a die head (17) for forming an extruded wall component having first and second end walls, with the die head (17) having therein formed a plurality of first dimensioned spaces (17a) and a plurality of seconds dimensioned spaces (17b), second dimensioned spaces (17b) having an opening (17c) located within each of said second dimensioned spaces (17b). The die (15) is secured to a manifold assembly (10), with the manifold assembly (10) comprising sets of tubes (16) located centrally to each other, each set of your bosses (16) comprising an inlet tube of water (150), a tube through which a vacuum (140) and a water return pipe (130) are drawn. Each set of tubes (16) is longitudinally positioned within a respective die manifold with the outermost surface of each set of tubes (16) separated a first dice from the respective die manifold. Each of the respective tubes (16) extends through the die (15).