HK1124568B - Fusion process for conduit - Google Patents

Description

Fusion process for pipeline

The application is a divisional application of Chinese patent application entitled "fusion process of pipes" filed in 2006, 1 month and 9 days, application number 200480019501.9, which is filed by underground solution Co.

Technical Field

The present invention relates generally to systems for fusing or joining pipe or pipe sections, such as polyvinyl chloride pipe, and more particularly to a fusion process for effectively and permanently joining a first pipe section to a second pipe section.

Background

Worldwide, piping systems are used in many applications to transport or transport materials, such as water or other fluids, from one location to another for distribution throughout the system. For example, bulky piping systems are used to distribute water for use and further processing by residential or industrial enterprises. Typically, such piping or tubing systems are located underground because the tubing above ground is both unsightly and inconvenient.

Typically, water piping systems transport materials through pipes made of different materials, such as cast iron, ductile iron, reinforced concrete, asbestos cement, and the like. These pipes are buried underground with branches extending in all directions to reach the end user. Generally, after many years of use, or for other reasons, underground pipes break and begin to leak, thereby reducing the pressure of the pipeline and allowing water to leak unnecessarily into the area surrounding the pipe. Such leakage not only impacts the system, but also increases the processing costs of the supplier, which in turn increases the costs to the end user. These leaks must therefore be repaired quickly and precautions taken to ensure that further leaks are avoided.

Repairing a leaking pipe is very labor intensive and time consuming due to the sub-surface location of the piping system. A trench must be dug down the pipeline to locate the leak and to effect repair of the pipe before it can be placed back for reuse. In accordance with the prior art, to seal leaking or broken pipes, various liner systems have been developed to either repair existing cracks or to preventively ensure that they are not broken or damaged any further. In addition, a method has been used which employs a much smaller diameter tube within a larger diameter cracked or broken tube. However, this is merely a problem of replacing the split outer tube with a cracked or leaking inner tube. Also, systems using such pipe-in-pipe significantly reduce the flow through the piping system and are clearly undesirable and can change pressure parameters.

To this end, a pipe liner and method of installation thereof has been developed, as disclosed in U.S. patent 5794662 to st. The onsge patent aims to provide a method of relining a sewer line, water pipe or natural gas pipe using a segmented liner of small size relative to the pipe being relined. However, the st.onge patent uses heat and/or pressure to swage small size tubes onto the relined tubes as opposed to leaving only small diameter liners in large diameter outer tubes. In particular, the inner or liner tube is a thermoplastic tube, typically a polyvinyl chloride (PVC) tube, which expands and molds against the inside of the existing pipe when exposed to heat or pressure, thereby effectively relining the pipe. Both the full length of the pipe and the damaged section can be lined with this process, which is commonly referred to as "field repair".

According to st.onge, once the full length of the liner tube is inserted into the existing or main tube, both ends of the liner tube are plugged and exposed to steam under pressure, thereby heating the liner tube along its length and applying pressure which causes the liner tube to expand and contact the inner wall of the surrounding main tube. Once the liner has fully expanded to conform to the existing inner wall of the pipe, it is cooled and the plug removed. The resulting expanded liner pipe conforms to the wall of the host pipe, thereby avoiding any further leakage. Likewise, the method of st.onge patent requires only trenching of both ends of the repaired pipe section.

Although the st. In particular, in order to transport and insert a liner pipe into a host pipe, the liner pipe must be manufactured in sections or portions, which are typically much shorter in length than the final and desired liner pipe length. Thus, when running a liner conduit into a host conduit, portions of the liner conduit must be joined on site. In addition, it is desirable to be able to connect multiple lengths of liner pipe through a joint having the strength of the original pipe without increasing the diameter of the joint area beyond the original pipe diameter. In addition to the expansion applications described above, the use of multiple and connectable tube sections is useful in many different applications. For example, the use of multiple and fused conduits is particularly useful in sliplining, where a slightly smaller diameter fused conduit is inserted into a larger diameter pipe that needs repair but does not require full capacity flow. In this case, the liner is pulled into the pipe and stays in place, but does not expand. In most cases, the space between the liner and the host pipe is filled with a low strength grout to secure the new pipeline in place. However, the slip-lining process may require the use of piping that can accommodate larger diameter couplings or mechanical joints.

Fused conduit is also desirable in various other applications, such as in rehabilitation applications, where a fused joint is used in conjunction with a horizontal drilling process. The method drills a pilot hole in the ground and can be precisely adjusted to control height and alignment. After the pilot hole is completed, the borehole is enlarged in diameter and filled with drilling mud to keep the larger hole open. The drill sleeve is then pulled through the drilling mud to form a pipe in situ. However, this process requires a larger drill to accommodate mechanical couplings and joints made of PE or HDPE.

Alternatively, fused conduit may be used in a pipe burst application. In pipe bursting, large hydraulic or pneumatic cutting heads are used to cut the old pipe and embed the fragments into the surrounding soil. This allows new pipe of the same or larger diameter to be pulled in from the existing pipeline. This process is used in situations where the capacity of a new pipeline must be significantly increased. Likewise, fused conduit is of course useful in direct-bury applications.

Fusion processes for pipes or conduits have been developed that employ mechanical joints, embedded wires at or near the fusion joints, or heat resistant elements to join the pipe sections together. See, for example, U.S. patent 6398264 to bryant.iii, U.S. patent 6394502 to Andersson, U.S. patent 6156144 to Lueghamer, U.S. patent 5921587 to Lueghamer, U.S. patent 4684789 to Eggleston, and U.S. patent 4642155 to Ramsey. For many years, welded polyethylene pipe (PE or HDPE) has been commonly used. See, for example, U.S. patent 3002871 to Tramm et al, U.S. patent 4987018 to Dickinson et al, U.S. patent 4963421 to Dickinson et al, and U.S. patent 4780163 to Haneline.Jr et al, and U.S. patent application publication 2003/0080552 to Genoni. Thus, an existing fusion apparatus can be obtained. However, the device must be modified in use and operating parameters for fusing polyvinyl chloride-based conduits. Unlike polyethylene pipe, which is typically joined by thermal fusion techniques, PVC pipe is generally limited in its application to applications where a sleeve joint may be used. This limitation limits the use of PVC pipe in skid-lined repairs. Accordingly, there is a need in the art to provide a PVC liner blank that is effectively a single element, without mechanical joints, which does not increase the diameter of the blank as would be the case with mechanical couplings. Such couplings or fusion joints must have similar strength characteristics to the original conduit and eliminate infiltration in the joint by eliminating such mechanical joints. Further, it is preferred that a coupling be provided that can withstand subsequent expansion processes and ultimately be used in a pressure conduit system.

Disclosure of Invention

It is therefore an object of the present invention to provide a fusion process for PVC pipe that overcomes the drawbacks of the prior art. It is another object of the present invention to provide a fusion process for PVC pipe that allows for the in situ joining of multiple lengths of PVC pipe. It is a further object of the present invention to provide a fusion process for PVC conduit that produces a joint having the same strength as the original conduit without having the joint area exceed the original conduit diameter. It is a further object of the present invention to provide a fusion process for PVC conduit that provides a one-piece blank without mechanical joints, which precludes permeation through such joints. It is a further object of the present invention to provide a fusion process for PVC conduit that produces a joint that can be subsequently expanded and used in pressure piping systems. It is a further object of the present invention to provide a fusion process for PVC conduit that produces a uniform joint with high strength characteristics. It is a further object of the present invention to provide a fusion process and apparatus which can be effectively used in conjunction with fusion pipes and joints in skid-lined, horizontal drilling, pipe break and in-line applications.

The invention aims to provide a welding process for pipelines. The fusion process includes an apparatus and a method for fusing a first conduit portion and a second conduit portion. The method comprises the following steps: (a) removably positioning the first terminal edge of the first conduit portion opposite the first terminal edge of the second conduit portion; (b) surface treating the first terminal edge of the first conduit portion and the first terminal edge of the second conduit portion; (c) aligning the first terminal edge of the first conduit portion with the first terminal edge of the second conduit portion; (d) melting at least a portion of the first terminal edge of the first conduit portion and the first terminal edge of the second conduit portion; (e) joining the melt terminal edge of the first conduit portion with the melt terminal edge of the second conduit portion; and (f) maintaining pressure between the joint terminal edges of the first and second conduit portions, thereby forming a fused joint region. This method may be employed where one or both of the first and second conduit portions are made of a polyvinyl chloride (PVC) material. The present invention also discloses novel operating parameters of a fusion apparatus for connecting a first conduit portion with a second conduit portion.

The present invention is also directed to a fusion apparatus for connecting a first conduit portion to a second conduit portion. The device includes: a first clamping mechanism for engaging and positioning the first conduit portion; and a second clamping mechanism for engaging and positioning the second conduit portion. A drive mechanism is operatively associated with one or both of the first clamping mechanism and the second clamping mechanism to drive them in a longitudinal direction. A surface treating mechanism is disposed between a terminal edge of the first conduit portion and a terminal edge of the second conduit portion. The surface treating mechanism "surface treats" or scrapes the terminal edges. A heater mechanism heats and melts one or both of the terminal edges of the conduit portions. One or both of the conduit portions are made of a polyvinyl chloride (PVC) material.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood from the following description of exemplary embodiments when read in connection with the accompanying drawings.

Drawings

FIG. 1 is a schematic view of a process for fusion of conduit according to the present invention;

FIG. 2 is a schematic view of an apparatus and system for fusion of conduit according to the present invention;

FIG. 3 is a side cross-sectional view of a fused joint area formed by the fusion process of conduit shown in FIG. 1;

figures 4-9 are graphs listing the optimum operating parameters at an interfacial pressure of 140psi for the process for welding the PVC pipe shown in figure 1, with specific numbers indicating nominal pipe diameter, pipe outside diameter, pipe inside diameter, surface area, gauge pressure and/or size ratio.

Detailed Description

For purposes of the following description, the terms "upper," "lower," "right," "left," "vertical," "horizontal," "top," "bottom," "lateral," "longitudinal," and derivatives thereof shall relate to the invention as oriented in the drawing figures. It is to be understood, however, that many alternatives, modifications, and variations in the steps of the present invention are possible, except where expressly stated to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting.

Various numerical ranges are disclosed herein. Because these numerical ranges are continuous, they include every value between the minimum and maximum values. Unless indicated otherwise, each specific numerical range given herein is an approximation.

The present invention is directed to a process for fusion of conduit, preferably a polyvinyl chloride (PVC) conduit, which includes fusing a first conduit portion 10 to a second conduit portion 12, as schematically illustrated in fig. 1, and employing a fusion apparatus 14 in this method. In a preferred embodiment, the method and fusion apparatus 14 may be used in conjunction with a pipeline expansion process and system to place a liner conduit 16 in a host conduit for subsequent expansion, the liner conduit 16 being formed from multiple conduit sections, such as first conduit section 10 and second conduit section 12. However, the method and fusion apparatus 14 may be used in any application where continuous fusion of conduit portions is desired. As mentioned above, the liner tube 16 is made of a thermoplastic material such as PVC. However, it is contemplated that any material having suitable expansion characteristics may be used and attached in accordance with the methods of the present invention. The fusion process of PVC pipe is effective for other similar expandable polymers and thermoplastics.

The ASTM standards for PVC pipe are applicable to a wide range of PVC resin additives having a variety of properties within the allowable combination of additives. However, not all possible combinations of additives will work in the pipe expansion process. That is, not all PVC water pipe will fuse to the same strength as the pipe material of the liner pipe, nor will all PVC pipe expand to the same size as the pipe material of the liner pipe.

Since the pipe expansion is carried out at a remote location, the liner 16 must be transported in sections. Thus, while the present invention specifically discusses the joining and welding of the first conduit portion 10 to the second conduit portion 12, the method and welding apparatus 14 may be equally used to join any number and length of liner conduit 16. Thus, in a further preferred and non-limiting embodiment, the fusion apparatus 14 is mobile and can be used in the field to carry out the method of the present invention.

Specifically, the present invention comprises the steps of: removably positioning the terminal edge 18 of the first conduit portion 10 opposite the terminal edge 20 of the second conduit portion 12 (step 100); surface treating the terminal edge 18 of the first conduit portion 10 and the terminal edge 20 of the second conduit portion 12 (step 120); aligning the terminal edge 18 of the first conduit portion 10 with the terminal edge 20 of the second conduit portion 12 (step 130); melting at least a portion of the terminal edge 18 of the first conduit portion 10 and the terminal edge 20 of the second conduit portion 12 (step 140); engaging the terminal edge 18 of the first conduit portion 10 with the terminal edge 20 of the second conduit portion 12 (step 150); and maintaining pressure between the terminal edge 18 of the first conduit portion 10 and the terminal edge 20 of the second conduit portion 12 to form a fused joint area 22 (step 160). In a preferred and non-limiting embodiment, the method further includes removing at least a portion of the resulting outer containment ring 24 that extends around the fused joint region 22 (step 170). The method is performed by a fusion apparatus 14, the fusion apparatus 14 being described in detail below.

Referring to step 100, the terminal edge 18 of the first conduit portion 10 is clamped or secured in place and positioned by the first clamping mechanism 26, while the second conduit portion 12 is clamped or positioned by the second clamping mechanism 28. The first clamping mechanism 26 and the second clamping mechanism 28 are part of the fusion apparatus 14 and removably position the first conduit portion 10 and the second conduit portion 12. Additionally, both the first clamping mechanism 26 and the second clamping mechanism 28 may be driven in a longitudinal direction, indicated by arrow a in fig. 2. Thus, the drive mechanism 30 is operatively associated with the first clamping mechanism 26 and/or the second clamping mechanism 28 to provide the requisite driving force to drive the first clamping mechanism 26 and/or the second clamping mechanism 28 into and out of the engaged position.

The terminal edge 18 of the first conduit portion 10 and the terminal edge 20 of the second conduit portion 12 must be surface treated to establish a clean and parallel mating surface. This facing is accomplished by a facing mechanism 32 that may be disposed between the terminal edge 18 of the first conduit portion 10 and the terminal edge 20 of the second conduit portion 12. For example, the facing mechanism 32 may be laterally moved into and out of position between the terminal edges (18, 20), as indicated by arrow B in FIG. 2. The facing mechanism 32 continues to grind or face the terminal edges (18, 20) until the distance between the first clamping mechanism 26 and the second clamping mechanism 28 is minimized. In a preferred and non-limiting embodiment, the surface treating mechanism 32 includes one or more blade portions 33. These blade portions 33 perform the actual cutting and surface treatment of the terminal edges (18, 20) of the pipe sections (10, 12). In another embodiment, the blade portion 33 is a carbide tipped blade, which provides better consistency and a cleaner surface treatment process. In addition, these carbide cutting edges allow the blade portion 33 to be used more frequently without wearing the cutting edges of the blade portion 33. Of course, other strength enhancing blades, coatings, structures and materials may be used.

It should be noted that the first clamping mechanism 26 and the second clamping mechanism 28 need not both be movable, as long as one is movable to engage the first conduit portion 10 and the second conduit portion 12. In operation, one or both of the first clamping mechanism 26 and the second clamping mechanism 28 are moved to securely and squarely lock the facing mechanism 32 between the first clamping mechanism 26 and the second clamping mechanism 28. This operation provides a substantially square surface perpendicular to the centre line of the first conduit portion 10 and the second conduit portion 12 without any gaps being detected. Additionally, the facing mechanism 32 may include blades having multiple angular orientations. This provides a smooth surface for the pipe sections (10, 12).

Next, the first conduit portion 10 and the second conduit portion 12 must be rounded in profile and aligned with each other to minimize mismatch of the conduit walls. This may be accomplished by adjusting the first clamping mechanism 26 and/or the second clamping mechanism 28 until the outer diameter of the first conduit portion 10 matches the outer diameter of the second conduit portion 12. It is desirable to not release the first clamping mechanism 26 and the second clamping mechanism 28 so that the first conduit portion 10 and/or the second conduit portion 12 may slide during the fusion process. The minimum distance required between the first clamping mechanism 26 and the second clamping mechanism 28 may be such that the first conduit portion 10 and/or the second conduit portion 12 surround a determined joint area as closely as possible. The closer to the joint area of the jaw pipe portions (10, 12), the easier it is for the operator to control proper alignment of the pipe portions (10, 12).

Next, the terminal edge 18 of the first conduit portion 10 and the terminal edge 20 of the second conduit portion 12 are heated or melted to the desired temperature, interface pressure and duration. In doing so, heat will penetrate into the first and second conduit portions 10, 12 and form a molten material bead at the terminal edges (18, 20). This heating process is performed by a heater mechanism 34 that simultaneously heats and melts the terminal edges (18, 20). This simultaneous heating may be accomplished by using first and second heated plates 36, 38, a single double-sided heated plate, or other means that can simultaneously heat the terminal edges (18, 20). Due to the surface treatment mechanism, the heater mechanism 34 should be movable to a position between the terminal edges (18, 20) until such time as the heating process is complete, at which point the heater mechanism 34 should be removed. Accordingly, the heater mechanism 34 should also be movable, such as laterally movable between the terminal edges (18, 20), as indicated by arrow C in fig. 2. In another preferred and non-limiting embodiment, the heater mechanism 34 provides zone heating relative to the surface of the heating ring mechanism 34, the first heated plate 36, and/or the second heated plate 38. Thus, different portions of the heating surface, such as the upper and lower surfaces, may have different temperatures. In this way, the terminal edges (18, 20) may be melted more uniformly due to the natural nature of the heating process, wherein the heat rises and creates a differential heating interface along the terminal edges (18, 20). Thus, the zone heating can form a uniform profile along the terminal edges (18, 20). It is also contemplated that the heater mechanism may include multiple zones controlled by control mechanism 40 or may be controlled by control mechanism 40. The control mechanism 40 provides for control of the various zones to maximize the efficiency and accuracy of the heater mechanism 34 and to provide a more uniform profile along the terminal edges (18, 20). The speed at which the heater mechanism is removed after the heating process is complete and the speed at which the terminal edges (18, 20) are clamped together are also important. Preferably, the time interval is short, such as 3 to 4 seconds.

It is also contemplated that the fusion apparatus 14 employs a control mechanism 40, typically integral with one or more measuring devices, to control the components. For example, the first heated plate 36 and/or the second heated plate 38 may be equipped with thermometers to measure plate temperatures, and an accompanying controller to set and stabilize these temperatures. However, these thermometers are only typical indicators due to the error between the actual temperature of the thermometer and the terminal edge (18, 20). In this regard, a pyrometer or other surface temperature measuring device may be integrated with the control mechanism 40 and periodically used to ensure the proper temperature of the first and/or second heated plates 36, 38. It is also contemplated that any of the control mechanism 40, the thermometer or other surface temperature measuring device is a digital device that can more accurately measure and control the amount of heat applied by the heater mechanism 34. Such a digital control arrangement is particularly advantageous when the fusion apparatus 14 is used in conjunction with PVC pipe, because the physical-chemical characteristics of PVC pipe, including its melting temperature and hardening temperature, require greater precision than if the fusion apparatus 14 were used in conjunction with PE or HDPE. Thus, this digital control, in combination with zone heating, provides better control characteristics for the fusion apparatus 14 of the present invention.

In addition, the heating plates (36, 38) should be kept clean and any coating on the heating plates (36, 38) should not be scratched or damaged in any way. After the terminal edges (18, 20) have been heated for the appropriate time and to the appropriate temperature, as will be discussed below, the heater mechanism 34 is removed and the molten terminal edges (18, 20) are brought together with sufficient pressure to properly mix the pipe material to form a homogeneous joint, referred to as a molten joint region 22.

The fused joint area 22 must be held firmly in place with pressure until cooled sufficiently to develop the appropriate strength. This should be accomplished by hydraulic pressure provided by the first clamping mechanism 26 and the second clamping mechanism 28. Sufficient cooling time before removal from the first clamping mechanism 26 and the second clamping mechanism 28 is important to obtain joint integrity.

After the fusion process, the fused joint area 22 reveals an outer bead 24 and an inner bead 42 as a result of the pressure exerted on the molten material. The outer bead 24 extends away from the fusion pipe outer wall 44 and similarly the inner bead extends inwardly from the fusion pipe inner wall 46. The outer bead 24 should be removed prior to using the first pipe section 10 in a pipe expansion process and system. Specifically, when subsequently used in the expansion process, the outer bead 24 should be removed so that the first pipe section 10 is fully expanded in the host pipe. The outer bead 24 is typically removed or machined to within 1/8 to 1/16 inches of the fused pipe outer wall 44. Generally, the inner bead 42 need not be cleaned, nor does it create unnecessary negative conditions in the liner 16. However, if such an inner bead 42 would be detrimental to the flow of material, the inner bead 42 would also be removed.

If the fusion process is unsuccessful or defective, the fused joint area 22 is simply cut and removed and the process repeated. However, the cause of the defect in the fused joint area 22 should be recorded in, for example, the control mechanism 40. The phenomena and data of the fusion process should also be processed, analyzed and demonstrated by the control mechanism 40.

For the fusion process operating parameters, the formula typically used to calculate fusion apparatus 14 gauge pressure using PVC liner conduit 16 is:

in addition, the formula used to calculate the surface area of the tubing or pipe (pSa) in square inches is:

the formula used to calculate gage pressure when the pipe or cylinder area is 1.00 square inches is:

Gp＝pSa×Ip

finally, when the tube surface area, the interfacial pressure, and the cylinder area of the machine are known, the formula used to calculate the gauge pressure of the machine is:

in the above formula:

MGp psi ═ machine gauge pressure

Pi-circumference ratio, 3.1416

OD²In inches by inches, square of the outside diameter

ID²Inch x inch as square of inside diameter

Interface pressure (140 psi), PVC pipe

Ca is the cylinder area of the machine in square inches

pSa is the area of the surface of the tube in square inches

Gp is gauge pressure when the cylinder area is 1.00

The tables in fig. 4-9 were developed through extensive testing and results recording for quickly establishing the various parameters for the above equations at an interface pressure of about 140 psi. In these tables, nominal pipe diameter, outer pipe diameter, inner pipe diameter, surface area, gauge pressure and size ratio are all listed. The cylinder pressure is based on 1.00. Additionally, to calculate the machine gauge pressure and psi using the tables of FIGS. 4-9, the listed gauge pressure and psi should be divided by the cylinder area (in square inches) of the machine used. To determine the appropriate gage pressure for all types and sizes of machines that may be used, the gage pressure indicated in the figures and tables should be divided by the effective cylinder area of the machine used.

The tube drag caused by the tube weight and roller resistance must be added to the calculated gauge pressure. In addition, extreme weather conditions such as wind, rain, high temperature, low temperature, snow, etc. must be considered and appropriately adjusted. Shelter is required for severe conditions. In addition, it can be noted that unlike polyethylene welding, PVC welding must be handled with care, particularly when axially lifted or bent. A spreader bar or "Y" sling can be used to safely handle the pipe. In addition, the use of a hot air blower or steam generator to heat a longer length of fused liner 16 allows the tube to become more flexible and safer to handle in cold weather.

Thus, the present invention provides a method and apparatus for a fusion process, which is particularly suitable for fusing polyvinyl chloride pipe. The method and apparatus can be used to join multiple sections or lengths of pipe to a joint of equal strength to the original pipe without increasing the diameter of the joint area beyond the diameter of the original pipe. Furthermore, the present invention currently invents a one-piece liner tube 16 blank without mechanical joints.

The invention has been described with reference to the preferred embodiments. Obvious modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations.

Claims (11)

1. A method of butt welding a first pipe portion to a second pipe portion, comprising:

facing at least one of the first terminal edge of the first conduit and the first terminal edge of the second conduit;

aligning the first terminal edge of the first conduit portion with the first terminal edge of the second conduit portion;

heating and melting at least a portion of a first terminal edge of a first duct portion and at least a portion of a first terminal edge of a second duct portion, wherein the first duct portion and the second duct portion are constructed of a polyvinyl chloride material, wherein heating and melting comprises contacting at least a portion of at least one of the first terminal edge of the first duct portion and the first terminal edge of the second duct portion with a heating plate having a temperature of about 415 ° f;

butt fusing the first and second pipe sections together by joining the heated and melted first terminal edge of the first pipe section with the heated and melted first terminal edge of the second pipe section at a joining interface pressure of about 140psi, thereby forming a butt fusion joint region such that the inner sidewall of the first pipe section does not overlap the inner sidewall of the second pipe section, the inner sidewall of the first pipe section does not overlap the outer sidewall of the second pipe section, and the inner sidewall of the second pipe section does not overlap the outer sidewall of the first pipe section; and

at least a portion of the resultant outer bead extending around the region abutting the fusion splice is optionally removed.

2. The method of claim 1, wherein each of the first pipe portion and the second pipe portion has a pressure rating of about 80psi to about 370psi at a water temperature of 73 ° f (23 ℃).

3. The method of claim 1, wherein each of the first pipe section and the second pipe section has a nominal pipe dimension of from about 3 inches to about 36 inches.

4. The method of claim 1, wherein heating and melting comprises contacting at least a portion of at least one of the first terminal edge of the first conduit portion and the first terminal edge of the second conduit portion with a heating plate.

5. The method of claim 1, further comprising removing at least a portion of the resultant outer bead extending around the region abutting the fusion splice.

6. The method of claim 1, further comprising:

heating and melting at least a portion of the second terminal edge of the first conduit portion and at least a portion of the first terminal edge of the subsequent conduit portion; and

joining the second terminal edge of the first conduit portion with the first terminal edge of the subsequent conduit portion, thereby forming a subsequent abutting fusion joint region.

7. The method of claim 1, wherein heating comprises simultaneously heating the first terminal edge of the first conduit portion and the first terminal edge of the second conduit portion.

8. The method of claim 1, wherein a plurality of heating zones are applied to at least a portion of at least one of the first terminal edge of the first conduit portion and the first terminal edge of the second conduit portion, the plurality of heating zones configured to provide a heating profile to at least a portion of at least one of the first terminal edge of the first conduit portion and the first terminal edge of the second conduit portion.

9. The method of claim 8, comprising automatically controlling at least one of the plurality of heating zones.

10. A method of butt welding a first pipe portion to a second pipe portion, comprising:

facing at least one of the first terminal edge of the first conduit and the first terminal edge of the second conduit;

aligning the first terminal edge of the first conduit portion with the first terminal edge of the second conduit portion;

heating and melting at least a portion of a first terminal edge of a first conduit portion and at least a portion of a first terminal edge of a second conduit portion, wherein heating and melting comprises contacting at least a portion of at least one of the first terminal edge of the first conduit portion and the first terminal edge of the second conduit portion with a heating plate having a temperature of about 415 ° f, wherein the first conduit portion and the second conduit portion comprise a polyvinyl chloride material;

butt fusing the first and second pipe portions together by joining the heated and melted first terminal edge of the first pipe portion with the heated and melted first terminal edge of the second pipe portion at a joining interface pressure of about 140psi, thereby forming a butt fusion joint region such that the inner sidewall of the first pipe portion does not overlap the inner sidewall of the second pipe portion, the inner sidewall of the first pipe portion does not overlap the outer sidewall of the second pipe portion, and the inner sidewall of the second pipe portion does not overlap the outer sidewall of the first pipe portion, and wherein the butt fusion joint region is free of a coupling between the first and second pipe portions; and

at least a portion of the resultant outer bead extending around the region abutting the fusion splice is optionally removed.

11. The method of claim 10, further comprising:

heating and melting at least a portion of the second terminal edge of the first conduit portion and at least a portion of the first terminal edge of the subsequent conduit portion; and

joining the second terminal edge of the first conduit portion with the first terminal edge of the subsequent conduit portion, thereby forming a subsequent abutting fusion joint region.