Method and apparatus for assembling high purity liquid dispensing system

Abstract

The invention relates to a method and apparatus for assembling a high purity liquid dispensing system. A method and apparatus for assembling a high purity liquid dispensing system. The distal end portion of the conduit is heated and then pushed over the sleeve so that the distal end portion may have a shrunk seal fit over the sleeve to reduce accidental or unintentional pull-out of the conduit from the fitting. Other benefits are also achieved, such as minimal flow constraint of liquid flowing through the joints and conduits.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 202080036598.3, titled "Method and Apparatus for Assembling a High-Purity Liquid Distribution System", filed on May 15, 2020. Technical Field

[0002] The various embodiments and aspects described herein relate to methods and apparatuses for assembling a high-purity liquid distribution system. Background Art

[0003] High-purity liquid distribution systems require various interconnected pipes and other components that control the flow of liquids used in semiconductor manufacturing. The liquid distribution systems operate at high temperatures and pressures above atmospheric pressure, and thus have certain unique requirements. When assembling these types of high-purity liquid distribution systems, there are certain drawbacks.

[0004] Therefore, there is a need in the art for an improved method and apparatus for assembling a high-purity liquid distribution system. Summary of the Invention

[0005] The aspects described herein address the drawbacks in the art. For example, machines, pipes, sleeves, fittings, and union nuts for assembling a high-purity liquid distribution system are shown. Additionally, a method of assembling a high-purity liquid distribution system using the machines, pipes, sleeves, fittings, and union nuts is described. The methods and apparatuses described herein allow for a shrink-fit connection between the pipe and the sleeve to increase the pull-out strength of the pipe when the joint is assembled. Furthermore, deformation in the joint is minimized to minimize fluid flow restriction through the joint. Additionally, the inner diameter of the joint is the same before and after the union nut is installed and after removal from the fitting.

[0006] More particularly, a method of joining a pipe made of PFA material to a sleeve made of PFA material is disclosed. The method may include the steps of heating a heating body to a temperature at least 15 degrees Celsius lower than the softening temperature of the PFA material; disposing a distal portion of the pipe in a hole formed in the heating body until the distal portion of the pipe is in a flexible state; disposing the sleeve on a cylindrical rod of a mandrel; holding the pipe by hand; while holding the pipe by hand, pulling the distal portion of the pipe out of the hole in the heating body; within 10 seconds after the removal step, pushing the heated distal portion of the pipe over the cylindrical rod and the sleeve; within 10 seconds after the pushing step, immediately removing the attached pipe and sleeve from the cylindrical rod of the mandrel; allowing the distal portion of the pipe to remain in air at a temperature between 15 degrees Celsius and 38 degrees Celsius until the temperature of the distal portion of the pipe is below 38 degrees Celsius.

[0007] The method may further include the step of reducing the inner diameter of the pipe at a rate faster than the outer diameter of the pipe to shrink a distal portion of the pipe onto the sleeve.

[0008] In the method, the pushing step may include the step of pushing a distal portion of the heated pipe until a distal end of the distal portion of the pipe contacts a stop flange of the sleeve.

[0009] In the method, a percentage of connection between an inner surface of the pipe and an outer surface of an enlarged portion of the sleeve and an outer surface of a cylindrical section of the sleeve having a reduced diameter may be equal to or greater than 75%. The percentage of connection may be between 90% and 96%.

[0010] In the method, the removing step may be performed within 3 seconds after the pushing step.

[0011] In the heating step, the heating body may be heated to a temperature between 250 degrees Celsius and 290 degrees Celsius.

[0012] In another aspect, a machine for installing a pipe onto a sleeve is disclosed. The machine may include a heating body having a bore with an inner diameter greater than the outer diameter of the pipe and the bore having a depth greater than 3 / 4 of the length of the sleeve; a heater in thermal communication with the heating body to transfer heat from the heater to the heating body to raise the temperature of the heating body to approximately the softening temperature of the pipe material; a controller in electrical communication with the heater and operable to turn the heater on and off; and a mandrel adjacent to the controller and having a cylindrical rod defining an outer diameter less than the inner diameter of the pipe.

[0013] The mandrel may further have a retainer sleeve slidably disposed on a distal portion of the cylindrical rod between an engaged position and a disengaged position. In the engaged position, a plurality of arms may extend outward from a central axis of the retainer sleeve and the cylindrical rod to a greater extent than when the retainer sleeve is in the disengaged position.

[0014] In another aspect, a method of attaching a pipe to a fitting is disclosed. The method may include the steps of: providing a pipe disposed on a sleeve, the sleeve and the pipe defining mating extrusion surfaces when connected to each other, which extend between a base and a vertex of an enlarged portion of the sleeve and have a conical configuration, the mating extrusion surfaces of the pipe and the sleeve being connected to each other over at least 75% of the length of the conical surface of the sleeve; inserting the pipe and the sleeve into the fitting; screwing a nut onto a thread of the fitting such that an extrusion surface of the nut contacts and bears against an outer surface of the pipe aligned with the mating extrusion surface; twisting the nut onto the fitting; and increasing the connection between the pipe and the sleeve at the conical surface by twisting the nut onto the fitting to a predetermined level.

[0015] In the method, the increment of the connection being increased may be at least 2%.

[0016] In this method, after the nut is twisted onto the fitting, the connection percentage can be 98% or greater. In this method, the nut can be twisted onto the fitting to a level that is limited to the level of the combined elastic limit of the sleeve, the pipe, and the fitting, such that if the nut is removed after the twisting step, the inner diameter of the sleeve remains the same as it was before the nut was twisted onto the fitting. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] These and other features and advantages of the various embodiments disclosed herein will be better understood with reference to the following description and drawings, where like numbers always refer to like parts, and where:

[0018] Figure 1 is a perspective view of a heating machine for connecting a pipe and a sleeve;

[0019] Figure 2 is Figure 1 a front view of the mandrel shown, with the sleeve disposed above the mandrel;

[0020] Figure 2A is Figure 2 a cross-sectional view of the mandrel and the sleeve shown;

[0021] Figure 2B is Figure 2A a partially enlarged view of the mandrel and the sleeve shown;

[0022] Figure 3 is a front view of the mandrel, with the sleeve disposed on the mandrel and the slidably retained sleeve in the upward position;

[0023] Figure 3A is Figure 3 a cross-section of the mandrel and the sleeve shown;

[0024] Figure 3B is Figure 3A a partially enlarged view of the mandrel and the sleeve shown;

[0025] Figure 4 is a front view of the mandrel and the sleeve, with the slidably retained sleeve in the downward position;

[0026] Figure 4A is Figure 4 a cross-sectional view of the mandrel and the sleeve shown;

[0027] Figure 4B is Figure 4A a partially enlarged view of the mandrel and the sleeve shown, with the pipe disposed above it;

[0028] Figure 5 is a perspective view of a union nut, a pipe, a sleeve, and a fitting;

[0029] Figure 5A is a front view of a union nut, a pipe, a sleeve, and a fitting;

[0030] Figure 6 is a front view of the pipe and the sleeve being aligned with each other before they are attached to each other;

[0031] Figure 7 is a front view of the pipe and the sleeve after they are attached to each other;

[0032] Figure 8 is a front view of the connected pipe and sleeve being aligned with the fitting before they are attached to each other;

[0033] Figure 9 is a front view of the connected pipe and sleeve and the fitting after they are attached to each other;

[0034] Figure 10 is a front view of the union nut, the connected pipe, the sleeve, and the fitting before the union nut is attached to the fitting;

[0035] Figure 11 is after the nut is screwed onto Figure 10 the fitting shown, a front view of the union nut, the connected pipe, the sleeve, and the fitting;

[0036] Figure 12 is Figure 11 an upright view of the assembly shown;

[0037] Figure 12A is Figure 12 a cross-sectional view of the assembly shown;

[0038] Figure 13 is a perspective view of the fitting;

[0039] Figure 13A is Figure 13 a front view of the fitting shown;

[0040] Figure 13B is Figure 13A a partially enlarged cross-sectional view of the fitting shown;

[0041] Figure 14 is a perspective view of the sleeve;

[0042] Figure 14A is Figure 14 a front view of the sleeve shown;

[0043] Figure 14B is Figure 14A a partially enlarged cross-sectional view of the sleeve shown;

[0044] Figure 15 is a perspective view of the pipe;

[0045] Figure 15A is a front view of the pipe;

[0046] Figure 15B is Figure 15A a cross-sectional view of the pipe shown;

[0047] Figure 16 is a perspective view of the union nut;

[0048] Figure 16A is Figure 16 a front view of the union nut shown; and

[0049] Figure 16B is Figure 16A a cross-sectional view of the union nut shown. DETAILED DESCRIPTION

[0050] Referring now to the drawings, various aspects of a heating machine 10 (see Figure 12A ) for making a fitting 20 (see Figure 1 ) for use in a high-purity liquid distribution system are disclosed. The fitting 20 can include a pipe 12 (see Figure 12A , Figure 15 - 15B ) and a fitting 16 (see Figure 12A , Figure 13 - 13B ). The pipe 12 can be attached to a sleeve 14 (see Figure 12A , Figure 14 - 14B ). The combined pipe / sleeve 12, 14 can be attached to the fitting 16 with a union nut 18 (see Figure 12A , Figure 16 - 16B ). The fitting 20 described herein can have a pipe pull-out force (i.e., the force required to pull the pipe 12 out of the fitting 16) high enough to withstand the operating pressure and temperature of a high-purity liquid distribution system. The high pull-out strength of the fitting 20 is achieved by one or more of the following: attaching the pipe 12 to the sleeve 14 after heating the pipe with the machine 10 and when the pipe is in a stress-relieved state (i.e., a flexible state), cooling the inner surface 48 (see Figure 15B ) of the pipe 12 at a rate faster than the cooling rate of the outer surface 82 (see Figure 15B ) of the pipe 12, and air-cooling the combined pipe 12 and sleeve 14 such that the combined pipe / sleeve is in a stress-relieved state after cooling. Further, since the inner diameter of the fitting 20 is not significantly less than the inner diameter 42 of the pipe 12 after the union nut 18 is torqued to the tightened level, the fitting 20 does not significantly restrict the flow of liquid through the high-purity liquid distribution system. After torquing the nut onto the fitting, the inner diameter of the fitting can be about 0% to 5% smaller than the inner diameter of the pipe, and more preferably 1% to 2% smaller (e.g., 1.5%). By providing an extrusion surface 132 (seeFigure 16B ) to achieve the smallest reduction in the inner diameter of the fitting 20, and this wide area applies pressure to the sleeve 14 above the wide area. Additionally, the nut 18 can be tightened onto the fitting 16 to a level where the fitting 20 does not exceed its elastic limit. This means that the inner diameter of the fitting 20 is the same before the union nut 18 is tightened onto the fitting 16 with the operating torque and after the union nut 18 is removed from the fitting 16.

[0051] More specifically, now referring to Figure 1 , the machine 10 assists in connecting the pipe 12 to the sleeve 14. The machine 10 can have a heating body 24. The heating body 24 can be in thermal communication with a heater (not shown). When heating the pipe 12 made of FEP (fluorinated ethylene propylene) or PFA (perfluoroalkoxy) material, the heater can heat the heating body 24 to a temperature of 180 degrees Celsius to 310 degrees Celsius. The heating body 24 can be attached to the base 26. The base 26 can also be used to fix the controller 28 and the mandrels 30a - e. The handle 32 can be attached to the base 26 to allow the user to lift and move the machine 10 from one position to another when assembling a high - purity liquid distribution system. The controller 28 and the heater of the machine 10 can be powered by a power outlet that is supplied through the wire 34.

[0052] The heating body 24 can be arranged in a vertical orientation. The heating body 24 can be attached to the rod 36, and the rod 36 supports the heating body 24 in the upward direction. The upward direction means that the holes 38a - e can have vertically aligned central axes. In this way, the pipe 12 to be inserted into one of the holes 38a - e is also vertically aligned. The pipe 12 located outside the heating body 24 can be held by a person's hand. First, the pipe 12 is inserted into the hole 38a - e, and then after the distillation end portion 40 of the pipe 12 has reached the desired temperature, the user can remove the pipe 12 from the heating body 24 and push the distillation end portion 40 of the pipe 12 (see Figure 15B ) onto the sleeve 14 that has been placed on one of the mandrels 30a - e.

[0053] The pipe 12 can be provided with various sizes defined by its outer diameter 41 (see Figure 15B ). The pipe 12 can be provided with an outer diameter of one - quarter inch, three - eighths inch, one - half inch, three - quarters inch, one inch, and one and a half inches. Other sizes between these are also conceivable. Each of these pipe sizes can have a different inner diameter 44 (see Figure 1)。The holes 38a-e may have an inner diameter slightly larger (e.g., about 3% to 5% larger) than the outer diameter 41 of the pipe 12. In this way, the distillation end portion 40 of the pipe 12 can be inserted into the appropriate holes 38A-E. The inner diameter 42 of the pipe 12 can be equal and between 0.125 inches and 2 inches. By way of example and not limitation, the inner diameter 42 of a 1 / 4-inch outer diameter pipe can be 5 / 32 inches, the inner diameter 42 of a 3 / 8-inch outer diameter pipe can be 1 / 4 inches, the inner diameter 42 of a 1 / 2-inch outer diameter pipe can be 3 / 8 inches, the inner diameter 42 of a 3 / 4-inch outer diameter pipe can be 5 / 8 inches and the inner diameter 42 of a 1-inch outer diameter pipe can be 7 / 8 inches.

[0054] By way of example and not limitation, a 1-inch outer diameter pipe 12 can be inserted into the hole 38e, which may have an inner diameter slightly larger than 1 inch (e.g., the inner diameter of the hole 38e can be about 1.01 inches). The 1 / 4-inch hole, the 3 / 8-inch hole 38b, the 1 / 2-inch hole and the 0.75-inch hole 38d can have inner diameters slightly larger, which are between 0.005 inches and 0.010 inches larger than the outer diameter and include 0.005 inches and 0.010 inches larger than the outer diameter. The holes 38a-e can have a depth 44 (see Figure 1 ), the depth being approximately equal to the sealing length 46 of the sleeve 14 or approximately 1 / 8 inch greater than the sealing length 46 of the sleeve 14. The sealing length 46 of the sleeve 14 is the area contacted by the inner surface 48 of the pipe 12 (see Figure 15B ) when the pipe 12 is joined to the sleeve 14.

[0055] The heating body 24 can be made of a metallic material. To insert the distillation end portion 40 of the pipe 12 into the hole 38, the user can hold the portion of the pipe 12 that does not enter the hole 38 with his or her hand. The user pushes the distillation end portion 40 into the appropriate hole 38a-e, waits until the distillation end portion 40 is heated to the appropriate temperature, and then pulls the distillation end portion 40 of the pipe 12 out of the hole 38ae.

[0056] To turn on or off the heater that heats the heating body 24, the user can operate the controller 28. Additionally, through the controller, the user can raise or lower the temperature of the heating body 24 to a suitable temperature. The controller 28 can have buttons, knobs, a pressure-sensitive screen to control the heater. The heating body 24 can be heated to 160 degrees Celsius (i.e., between 140 degrees Celsius and 180 degrees Celsius) for pipes made of FEP material and can be heated to approximately 270 degrees Celsius (i.e., between 250 degrees Celsius and 290 degrees Celsius) for pipes made of PFA material.

[0057] Now referring to Figure 2 - 4B , as represented in these figures Figure 1One of the mandrels 30a-e shown. The mandrel 30 can be attached to the base 26 by a rod 50. A protective sleeve 52 ( Figure 1 ) can be attached to the rod 50 by a screw 54 to mitigate harm to a person. For example, if the protective sleeve is not used, a pipe 12 heated to above 200 degrees Celsius may be contacted by a person assembling the fitting 20 and burn the person. The protective sleeve provides a protective barrier. Additionally, the protective sleeve can also be used as an insulator. As discussed herein, the inner surface 48 of the pipe 12 cools faster than the outer surface 82 of the pipe 12. By placing the protective sleeve 52 around the mandrel 30, the protective sleeve 52 can be used as an insulator for the outer surface 82 of the pipe 12 to retain heat within the distal portion of the pipe. Although the protective sleeve 52 is described as helping to promote faster or slower cooling of the outer surface 82 of the pipe compared to the inner surface 48 of the pipe, the protective sleeve is not a necessary component for promoting faster cooling of the inner surface 48 compared to the outer surface 82. The heat transfer coefficients of the rod 67 (see Figure 2B ) and the sliding collar sleeve 64 (see Figure 2B ) can be high enough such that even without the protective sleeve 52, when the pipe 12 and the sleeve 14 are cooled in ambient air at a temperature between 20 degrees Celsius and 44 degrees Celsius, the inner surface 48 of the pipe 12 cools faster than the outer surface 82 of the pipe 12. For purposes of simplicity and clarity, Figure 2 - 4B the mandrels 30a-e shown are shown without the protective sleeve 52.

[0058] The mandrels 30a-e can have an outer diameter 54 and a stop surface 56, as Figure 2B shown. When the sleeve 14 is disposed on the mandrels 38a-e, as Figure 3B shown, the distal end 58 of the sleeve 14 (see Figure 2B ) contacts the stop surface 56. In this position, the opposite end portion 60 of the sleeve 14 is aligned with the shoulder surface 62 of the mandrels 30a-e.

[0059] The mandrels 30a-e can have a sliding collar sleeve 64. The sliding collar sleeve 64 can be laterally moved to an upward position as Figure 3B shown and a downward position as Figure 4B shown. The sliding collar sleeve 64 can have a plurality of arms 66 (see Figure 3 and Figure 4 ), and when the sliding collar sleeve 64 is transferred from the upward position (see Figure 3 ) to the downward position (see Figure 4 ), the plurality of arms 66 extend, as Figure 4 shown.

[0060] The stem 67 of the mandrel 30a-e can define the outer diameter 54, the shoulder surface 62, and the retainer stop. The retainer stop prevents the sliding retainer sleeve 64 from being removed from the stem 66 and defines the upward and downward positions of the sliding retainer sleeve 64. In particular, the stem 66 can have an upper groove 68 (see Figure 4B ) and the lower groove 70 (see Figure 3B ). The sliding retainer sleeve 64 may have a protrusion 72 that is received in the upper and lower grooves 68, 70 when the sliding retainer sleeve 64 is in the upper and lower positions. Figure 4B As shown, arms 66 are extended due to shoulder surface 62 pushing arms 66 outward.

[0061] In this downward position, the distal end portion of the arm 66 is located at the position defined by the chamfer 74 (see Figure 4B and Figure 14B ) and shoulder surface 62 (see Figure 4B ) is within the gap formed. Therefore, when the pipe 12 is pushed over the sleeve 14, the distal end 76 (see Figure 4B ) will not be due to the edge 78 and inner diameter 80 of the sleeve 14 (see Figure 3B ) between the gap or lip 83 (see Figure 3B ) and at the edge 78 of the sleeve 14 (see Figure 3B However, because the distal end portion of the arm 66 of the retainer sleeve 64 abuts against the chamfer 74, any misalignment of the pipe 12 with the sleeve 14 is prevented by Figure 4B The arm 66 is aligned with the position shown in FIG. 1 so that the distal end 76 of the pipe 12 does not get caught on the edge 78 of the sleeve.

[0062] When the pipe 12 is pushed over the sleeve 14, the inner surface of the pipe contacts the outer surface of the sleeve. Heat from the inner surface of the pipe is transferred out of the inner surface through this contact at a faster rate than the rate at which heat is transferred from the outer surface of the pipe. When the pipe 12 is placed over the sleeve 14 and on the rod 67, the rod 67 and the sliding retainer sleeve 64 of the mandrel 30a-e and the sleeve 14 can contact the outer surface 82 of the pipe (see Figure 15B ) draws heat away from the inner surface 48 of the heated distal portion 40 of the pipe 12 at a greater rate than the outer surface 82 of the pipe 12, so that the inner surface 48 of the pipe 12 can shrink at a faster rate than the outer surface 82 of the pipe 12. The rod 67 can be made of a material having a higher heat transfer coefficient than air. By way of example and not limitation, the rod 67 can be made of a metal material including, but not limited to, aluminum. In addition, the outer surface of the rod 67 can have a nickel alloy coating to further assist in the rapid thermal transfer of heat away from the inner surface 48 of the pipe 12 and into the rod 67 through the inner surface 48 of the pipe 12. It is also contemplated that the sleeve 14 can draw heat away from the inner surface of the distal portion of the pipe at a faster rate than the outer surface exposed to air.

[0063] In addition, to facilitate heat transfer from the inner surface 48 of the pipe, the slip guard sleeve 64 can be made of the same material as the pipe 12 and the sleeve 14. Preferably, the pipe 12 and the sleeve 14 can be made of FEP (fluorinated ethylene propylene) or PFA (perfluoroalkoxy) materials. Although the pipe 12 and the sleeve 14 can be made of the same material, it is also conceivable that the pipe 12 and the sleeve 14 can be made of different materials, including but not limited to the case where the pipe 12 can be made of FEP material and the sleeve 14 can be made of PFA material, and vice versa.

[0064] Optionally, it is also conceivable that a thermoelectric cooler can also be attached to the rod 67 to actively draw heat away from the rod 67, thereby cooling the inner surface 48 of the pipe 12 faster than the outer surface 82 of the pipe. In addition, it is also conceivable that a heat sink can be attached to the rod 67 to further draw heat away from the rod 67, such that the inner surface 48 is cooled faster than the outer surface 82 of the pipe 12.

[0065] For the purpose of alleviating the distal end 76 of the tube 12 from jamming against the edge 78 produced by the chamfer 74 of the sleeve 14, the mandrels 38a-e are shown with a slip guard sleeve 64. However, it is also conceivable that the sleeve 14 can be made without the chamfer 74, such that the opposite end portion 60 of the sleeve 14 has a sharp edge that is not separated from the outer surface of the rod 67 by a gap or a lip 83. There is no lip 83 on the opposite end portion of the sleeve 14 that might get caught on the distal end 76 of the tube 12. In this regard, the slip guard sleeve 64 is not required.

[0066] The slip guard sleeve 64, the rod 67, the sleeve 14, and the pipe 12 can be cylindrical. The cross-sections shown in the figures of these components can be characterized as any cross-section passing through the central axes of the components 64, 67, 14, and 12. The same applies to the union nut 18 and the fitting 16, except for the outer surface of the nut 18 and the threads formed thereon.

[0067] Now referring to Figure 5 and Figure 13 - 16B , the fitting 16, the sleeve 14, the pipe 12, and the union nut 18 are shown. As Figure 13 - 13B shown, the fitting 16 can have (a) thread(s) on the opposite end portion of the fitting 16. However, it is also conceivable that the fitting 16 can have (a) thread(s) 86 only on one side of the fitting 16, and can be a tubular structure, such as a bent pipe, a pipe, a valve, or other configurations, on the other side of the fitting 16. The thread 86 of the fitting 16 can match the thread 88 of the union nut 18 (see Figure 16B ). The fitting 16 can also have a wrench surface 90 to assist in holding the fitting 16 stationary when tightening the union nut 18 onto the fitting 16.

[0068] Now referring toFigure 13B , the fitting 16 may have a chamfered surface 92 that receives the pipe 12, where the pipe 12 flares outwardly due to the enlarged portion 94 of the sleeve 14 (see Figure 14B ). The chamfered surface 92 of the fitting may be at the same angle as the conical surface 116 of the sleeve 14. The fitting 16 may also have a straight cylindrical surface 96 that receives the straight portion 98 of the pipe 12 (see Figure 12A ) and the straight portion 100 of the sleeve 14 (see Figure 12A ). Figure 14B The straight section 100 of the sleeve 14 is shown. The straight section 100 may also have a step 102. However, even with the step 102, the straight section can still be considered straight. The fitting 16 may also have a recess 104 that receives the protrusion 106 of the sleeve 14 (see Figure 14B ). The fitting 16 may also define an inner diameter 108 that may be equal to the inner diameter 42 of the pipe 12 (see Figure 15B ). As Figure 12A shown, when assembled, the fluid 22 flowing through the pipe 12 also flows through the sleeve 14 and the fitting 16. However, since the inner diameter 108 of the fitting 16 and the inner diameter 110 of the sleeve (see Figure 14B ) are equal to the inner diameter 42 of the pipe 12, the fluid 22 maintains laminar flow through the joint 20 and also does not create any significant friction to the flow of the fluid 22 through the joint 20.

[0069] Now referring to Figure 14 - 14B , the sleeve 14 is shown. The sleeve 14 defines an enlarged portion 94 having an outer diameter 112 at its apex. The apex may be a flat cylindrical surface. Additionally, the enlarged portion 94 may also have two conical surfaces 114, 116. The conical surface 114 extends from the edge 78 to the cylindrical surface 118 of the apex. The conical surface 116 may extend from the apex of the enlarged portion 94 to a reduced-diameter cylindrical section 120. The reduced-diameter cylindrical section may have an outer diameter 112 that is less than the outer diameter 112 of the enlarged portion 94. As discussed herein, the chamfer 74 of the sleeve 14 is optional.

[0070] The conical surface 114 of the sleeve 14 may be referred to as the extrusion surface. The conical surface 114 may make an angle 113 (see Figure 14B ) equal to and between 10 degrees and 65 degrees with the central axis 111 of the sleeve 14 (see Figure 14B) Preferably, the angle 113 can be at an angle of 15 degrees to 45 degrees (e.g., 30 degrees) with respect to the central axis 111. The length 115 of the conical surface 114 can be equal to or between 10% and 27% of the length 117 of the sleeve 14, and more preferably can be equal to or between 17% and 20%. By way of example and not limitation, the length 115 of the conical surface 114 of the sleeve for a 1 / 4-inch outside diameter pipe is 0.090 inches, the length 115 of the conical surface 114 of the sleeve for a 3 / 8-inch outside diameter pipe is 0.127 inches, the length 115 of the conical surface 114 of the sleeve for a 1 / 2-inch outside diameter pipe is 0.132 inches, the length 115 of the conical surface 114 of the sleeve for a 3 / 4-inch outside diameter pipe is 0.173 inches, and the length 115 of the conical surface 114 of the sleeve for a 1-inch outside diameter pipe is 0.218 inches. The dimensions of the length 115 for pipes having different outside diameter sizes can be set to fall within the above ratios. The length 115 of the conical surface 114 receives the force applied to it by the union nut over a wide area to distribute the load over the sleeve 14 and to relieve the inward deflection or reduction of the inner diameter 110 of the sleeve 14 when the nut 18 is twisted onto the fitting 16. As Figure 12A shown, as the union 18 is twisted onto the fitting 16, the union 18 pushes the pipe 12 against the tapered surface 114. In doing so, the sleeve 14 is further pushed into the fitting 16. Additionally, the conical surface 116 bears against the pipe 12, and the pipe 12 also bears against the chamfered surface 92 of the fitting 16. In other words, the pipe 12 is clamped between the chamfered surface 92 of the fitting 16 and the conical surface 116 of the sleeve 14, as Figure 12A shown. This forms a liquid-tight seal between the conical surface 116 and the inner surface of the pipe in contact therewith to prevent the liquid 22 from flowing out of the joint 20. The conical surface 116 can have the same size as the conical surface 114. The conical surface 116 can be in a mirror configuration with respect to the conical surface 114 or different from the conical surface 114 but within the scope stated herein for the conical surface 114.

[0071] In addition, as discussed herein, when the distal portion 40 of the conduit 12 is pushed over the enlarged portion 94 of the sleeve 14, the distal portion 40 of the conduit 12 is in a flexible state. In the flexible state, the distal portion 40 of the conduit is heated and its elastic range is increased. Additionally, the stress within the distal portion 40 of the conduit 12 is eliminated. When the distal portion 40 of the conduit 12 is pushed over the enlarged portion 94, the stretching of the distal portion 40 of the conduit does not exceed the elastic limit of the flexible distal portion. Further, it is contemplated that the enlarged portion 94 may stretch the distal portion 40 of the conduit 12 but not significantly exceed its elastic limit such that after the distal portion 40 has cooled, the inner diameter 42 of the conduit 12 does not fall back to the outer diameter 122 of the reduced diameter cylindrical portion 120 of the sleeve 14. After the distal portion 40 of the conduit 12 has cooled, the cooling of the distal portion 40 of the conduit and the elasticity of the distal portion 40 of the conduit may be sufficient to shrink or reduce the inner diameter 42 of the conduit such that the inner surface of the distal portion 40 of the conduit may compress against the reduced diameter cylindrical section 120 and the conical surface 116 of the sleeve 14. The compression of the inner surface 48 of the conduit against the sleeve 14 creates a gapless connection along more than 75% and up to 95% (e.g., more preferably 90% to 95%) of the length of the enlarged portion 94 and the reduced diameter cylindrical section 120 between the inner surface 48 of the conduit and the outer surface of the sleeve 14. The conduit 12 is not spaced apart from the conical surface 116 of the sleeve 14 by a gap. The distal portion 40 of the conduit 12 contracts and elastically compresses onto the sleeve 14 to enhance the tight connection between the distal portion 40, and more specifically, between the portion of the conduit 12 that abuts against the conical surface 116 of the sleeve 14. In order to pull the conduit 12 away from the sleeve 14, the elastic limit of the conduit 12 must be exceeded. Thus, the pull force of the conduit 12 from the sleeve 14 is high enough to withstand the operating conditions of the high purity liquid distribution system.

[0072] Now referring to Figure 15 - 15B , the conduit 12 is shown. The conduit 12 may have a length 124 that is long enough such that a user can grasp the conduit with his or her hand and still insert the distal portion 40 into the aperture 38 of the heating body 24. It is also contemplated that in situations where a shorter conduit 124 is to be incorporated into the high purity liquid distribution system, instead of grasping the conduit 12 with a human hand, a grasping device may be used to grasp the conduit.

[0073] Now referring to Figure 16 - 16B, shows a union nut 18. The union nut 18 may have a toothed configuration on its outer side. These toothed protrusions 126 assist in applying torque to tighten the nut 18 onto the fitting. The union nut 18 has an inner diameter 128 that is greater than the outer diameter 41 of the pipe 12. This allows the pipe 12 to be inserted into the hole 130 of the nut 18 during the assembly of the joint 20. The union nut 18 also has an extrusion surface 132. By way of example and not limitation, the length 133 of the extrusion surface 132 is 0.079 inches for a 1 / 4 inch outside diameter (O.D.) pipe, 0.099 inches for a 3 / 8 inch O.D. pipe, 0.099 inches for a 1 / 2 inch O.D. pipe, 0.115 inches for a 3 / 4 inch O.D. pipe, and 0.140 inches for a 1 inch O.D. pipe. The dimension of the length 133 (see Figure 16B ) for pipes having different outside diameter sizes can be set to conform to the above ratios. By way of example and not limitation, the length 133 can be between 40% and 95% of the length 115 of the conical surface of the sleeve (see Figure 14B ). More preferably, the length 133 can be 75% plus or minus 15% of the length 115. The extrusion surface 132 can have a conical configuration that can be at the same angle as the conical surface 114 of the sleeve 14 (see Figure 12A ). During the assembly of the joint 20, the extrusion surface 132 of the union 18 bears against the outer surface of the pipe 12 at the location of the conical surface 114 of the sleeve 14. The distal portion 40 of the pipe 12 is heated so that it conforms to the profile of the sleeve 14. Thus, the union nut 18 does not dig into the outer surface of the pipe 12 and does not create stress concentrations on the pipe 12. In addition, the union nut 18 does not apply sharp needle tip pressure to the pipe 12. Instead, the nut 18 transfers the force over a wide area to the sleeve through the extrusion surface 132 to better distribute the pressure applied to the pipe 12 and the sleeve 14. This results in a smaller deformation of the sleeve 14 and thus a minimal interruption of the fluid flow 22 through the sleeve 14. In addition, when the union nut 18 is twisted onto the fitting 16, the connection percentage along the length of the enlarged portion and the diameter-reducing cylindrical section 120 between the inner surface of the pipe and the outer surface of the sleeve can increase by more than 2% (e.g., 75% to 77%, 95% to 97%, or 90% to 95% to 92% to 97%). Preferably, when the union nut 18 is twisted onto the fitting 16, the connection percentage along the length of the enlarged portion and the diameter-reducing cylindrical section between the inner surface of the pipe and the outer surface of the sleeve can be increased to 99% to 100%.

[0074] To assemble a high purity liquid distribution system, a tube 12 is attached to a ferrule 14. These ferrules 14 are used to attach the tube 12 to various fittings 16 required in the high purity liquid distribution system. To install the tube 12 to the ferrule 14, a user turns on a heating machine 10 to heat the heating body 24. The temperature of the heating body 24 is set to a temperature depending on the type of material of which the tube 12 is made. The user can control the temperature of the heating body 24 through a controller 28 of the machine 10. Once the heating body 24 has been heated to a desired temperature, the user holds the tube 12 and inserts a distal portion 40 of the tube 12 into a suitable hole 38a - e. Then the heating body 24 heats the distal portion 40 of the tube 12 until the distal portion 40 reaches a temperature equal to or between the softening temperature and the melting temperature of the tube material that is below 15 degrees Celsius. Preferably, the heating body 24 heats the distal portion 40 of the tube 12 to at least the softening temperature of the tube material. At this time, the distal portion 40 of the tube 12 can be characterized as being in a flexible state. Generally, the distal portion 40 of the tube 12 remains in the heating body 24 for about 45 seconds so that the temperature of the distal portion 40 can reach the same temperature as the heating body 24. When the distal portion 40 of the tube 12 is in a flexible state, the inner diameter and the outer diameter of the tube 12 will increase by about 3% to 4%. This makes it easy for the distal portion 40 of the tube 12 to be pushed over an enlarged portion 94 of the ferrule 14. Additionally, the flexible state increases the elastic limit of the material such that when the distal portion 40 of the tube 12 passes over the enlarged portion 94 of the ferrule 14, the stretching of the tube 12 above the enlarged portion 94 of the ferrule 14 does not exceed the elastic limit of the distal portion 40 of the tube 12 in the heated condition. If the distal portion 40 of the tube 12 does exceed its elastic limit when it is pushed over the enlarged portion 94 of the ferrule, it does so only slightly such that the distal portion 40 of the tube 12 can elastically close on the ferrule 14.

[0075] Once the distal portion 40 of the tube 12 has reached a flexible state in the heating body 24 of the heating machine 10, the distal portion 40 of the tube 12 is removed from the heating body 24. As Figure 2B shown, before the distal portion 40 of the tube 12 is removed from the heating body 24, a sliding retainer sleeve 64 is laterally moved to an upward position. The ferrule 14 is then positioned above a rod 67 of a mandrel 30. As Figure 3B shown, a distal end 58 of the ferrule 14 contacts a stop surface 56 of the mandrel 30. As Figure 4B shown, the sliding retainer sleeve 64 is laterally moved to a downward position. As Figure 4BAs shown, the pipe 12 can be removed from the heating body 24 and then inserted above the sleeve 14. Any misalignment of the pipe 12 with the sleeve 14 can be corrected by sliding the arm 66 of the guard ring sleeve 64, which spreads outwardly and is arranged within the chamfer 74 and the shoulder surface 62 of the sleeve 14, as Figure 4B shown.

[0076] The size of the inner diameter 42 of the pipe 12 is preferably set to be equal to or between the inner diameter 110 of the sleeve 14 and the outer diameter 122 of the diameter-reduced cylindrical section 120 of the sleeve 14. Preferably, the inner diameter 42 of the pipe 12 is equal to the inner diameter 110 of the sleeve 14. As the distal portion 40 of the pipe 12 is inserted above the enlarged portion 94, the distal portion 40 is drawn out. Since the distal portion 40 is heated to be in a flexible state, the distal portion 40 of the pipe 12 has an increased range of its elastic limit. Therefore, when the distal portion 40 is drawn out due to the enlarged portion 94 of the sleeve 14, it is preferably not overextended beyond the elastic limit of the distal portion 40. More preferably, the distal portion 40 remains within the elastic limit. When the distal portion moves past the apex of the enlarged portion 94, the distal portion 40 contracts or closes due to its elasticity and compresses against the conical surfaces 114, 116 and the diameter-reduced cylindrical section 120.

[0077] In addition, since the material of the rod 67, the coating on the rod 67, the material of the slip guard sleeve 64, and the sleeve 14 itself can transfer heat faster than air, the heat transfer rate from the inner surface 48 of the pipe 12 is greater than the heat transfer rate from the outer surface of the pipe 12. In other words, the heat transfer coefficient of these components together or as a system is greater than the heat transfer coefficient of air. Since the inner surface 48 of the pipe 12 cools at a faster rate compared to the outer surface 82, the distal portion 40 further shrinks on the sleeve 14 to form a joint with a tight-fitting surface between the pipe 12 and the sleeve 14. When the pipe 12 is inserted over the sleeve 14, the distal end 76 of the pipe 12 is inserted until the distal end 76 of the pipe contacts the step surface 134 on the sleeve 14. Since the distal portion 40 of the pipe 12 is flexible, the user can push the pipe 12 until the distal end 76 of the pipe 12 contacts the step surface 134 of the sleeve 14. In addition, due to the contact between the end surface 76 and the step surface 134, when the union nut 18 further pushes the pipe 12 and the sleeve 14 into the fitting 16, the force is transferred from the distal end 76 of the pipe 12 into the step surface 134 to further assist in the engagement of the assembly or the joint assembly 20. Once the distal portion 40 of the pipe 12 is fully inserted over the sleeve 14, the user may wait for 1 second to 3 seconds before removing the distal portion 40 of the pipe 12 and the sleeve 14 from the mandrel 30. The user lifts the pipe 12 to remove the sleeve 14 and the pipe 12 from the mandrel 30. When the user lifts, the sleeve 14 pushes the slip guard sleeve 64 upward to drag the arm 66 inward and allows the sleeve 14 to be removed from the mandrel 30. The distal portion 40 of the pipe 12 can then be air-cooled before assembling the joint 20. Air-cooling allows the distal portion 40 of the pipe and the sleeve 14 to be stress-relieved after cooling. Once the distal portion 40 is air-cooled, there is a tight-fitting contact between the inner surface 48 of the pipe 12 and the outer surface of the sleeve 14. In addition, the portion of the distal portion 40 disposed between the apex of the enlarged portion 94 and the step surface 134 is re-shaped into this configuration.

[0078] After the distal portion 40 is cooled, the elastic limit of the distal portion is now smaller. In order to remove the distal portion 40 of the pipe 12 from the sleeve, the portion of the pipe 12 between the apex of the enlarged portion 94 of the sleeve and the step surface 134 must be stretched more. Since the elastic limit of the cooled distal portion 40 of the pipe 12 is reduced, this is difficult to do. This helps to hold the pipe 12 on the sleeve 14.

[0079] Now referring Figure 5 - 12A , the assembly of the joint 20 is discussed. In particular, as described above, the distal portion 40 of the pipe 12 can be disposed over the sleeve 14. This is in Figure 6 and Figure 7shown. After the pipe 12 is attached to the sleeve 14, the sleeve 14 is inserted into the fitting 16, as Figure 8 and Figure 9 shown. The projection 106 of the sleeve is inserted into the recess 104 of the fitting 16 ( Figure 12A ). As Figure 10 and Figure 11 shown, the union nut 18 can then be screwed onto the fitting 16.

[0080] The cross-section of the joint 20 is shown in Figure 12A . The union nut 18 can be twisted to apply pressure to the sleeve 14 through the pressing surface 132 of the nut 18. This force is transmitted through the pipe 12 into the conical surface 114 of the sleeve 14. The axial direction component of this pressure applies a compressive force to the pipe 12 between the chamfered surface 92 of the fitting 16 and the conical surface 116 of the sleeve 14 to form a liquid-tight seal between them.

[0081] The squeezing surface 132 of the union nut 18 also applies an inwardly directed force on the conical surface 114. This inwardly directed force is perpendicular to the axial direction. However, since the squeezing surface 132 applies this force over a wide area, a minimum inward deflection of the sleeve 14 occurs near the conical surface 114 of the sleeve 14. By way of example and not limitation, the inner diameter of the sleeve 14 can be reduced by an amount equal to and between 0.25% and 1.75%, and more preferably a minimum reduction of about 1% can be achieved. Before the union nut 18 is twisted onto the fitting 16, the union nut 18 is twisted onto the fitting 16 until the inner diameter 110 of the sleeve 14 returns to its initial inner diameter level. In other words, before the distal portion 40 is connected to the sleeve 14, the sleeve has an inner diameter 110 of 0.87 inches for a 1.00 inch outer diameter pipe. After the distal portion of the pipe 12 is connected to the sleeve 14, the inner diameter 110 of the sleeve 14 is slightly smaller due to the compressive force applied by the pipe 12 to the sleeve. When the pipe 12 and the sleeve 14 are inserted into the fitting 16, the sleeve 14 can also apply an inwardly directed compressive force to further reduce the inner diameter 110 of the sleeve 14. When the union nut 18 is twisted onto the fitting 16, the squeezing surface 132 of the nut 18 applies an inward pressure on the pipe 12 and the sleeve 14. Preferably, after the nut 18 is twisted and removed, the inner diameter of the fitting 12 is the same as the inner diameter of the fitting 20 before the nut 18 is twisted onto the fitting 16. The inner diameter of the fitting 20 is determined by inserting a round gauge into the fitting. The torque applied to the nut 18 does not cause the fitting 20 to exceed its elastic limit. In other words, before the nut is twisted onto the fitting 16, the inner diameter of the fitting 20 is determined. The nut is twisted onto the fitting and then removed. Optimally, the inner diameter of the fitting 20 is tested to ensure that the inner diameter is the same before the nut 18 is twisted onto the fitting 16. The maximum torque is at the level just before the inner diameter of the fitting 20 is smaller after the nut 18 is twisted and removed from the fitting 16.

[0082] The high purity liquid distribution system employing the fitting 20 can operate at liquid temperatures equal to and between 21 degrees Celsius and 200 degrees Celsius and at pressures between 37 pounds per square inch and 276 pounds per square inch. The high purity liquid distribution system is also known as a chemical distribution system and is also referred to by the abbreviations CCSS, CDS, or SDS and refers to the fluid or liquid transported by the system. The high purity liquid distribution system discussed herein can transport liquids having a high acidity between 0 - 14 and can transport fluids such as sulfuric acid. The fitting 20 described herein can meet the Standard SemiF57 - 0301 standard.

[0083] The above description has been presented by way of example and not limitation. Given the above disclosure, those skilled in the art can devise variations within the scope and spirit of the invention disclosed herein. In addition, the various features of the embodiments disclosed herein can be used separately or in different combinations with each other and are not intended to be limited to the specific combinations described herein. Accordingly, the scope of the claims is not limited by the illustrated embodiments.

Claims

1. A method of connecting a pipe made of perfluoroalkoxy, i.e., PFA material, to a sleeve made of the PFA material, the method comprising the following steps: Heating a heating body to at least 15 degrees Celsius lower than the softening temperature of the PFA material; Arranging a distal portion of the pipe in a hole formed in the heating body until the distal portion of the pipe is in a flexible state; Arranging a sleeve on a cylindrical rod of a mandrel; Removing the distal portion of the pipe from the hole in the heating body; After the removing step, attaching the pipe to the sleeve by arranging the heated distal portion of the pipe over the cylindrical rod and the sleeve to facilitate the inner surface of the pipe cooling faster than the outer surface of the pipe; After the arranging step, removing the attached pipe and sleeve from the cylindrical rod of the mandrel; allowing the distal portion of the pipe to remain in air at a temperature between 15 degrees Celsius and 38 degrees Celsius until the temperature of the distal portion of the pipe is below 38 degrees Celsius.

2. The method according to claim 1, further comprising the step of reducing the inner diameter of the pipe at a faster rate than the outer diameter of the pipe to shrink the distal portion of the pipe onto the sleeve.

3. The method according to claim 1, wherein the arranging step comprises the step of pushing the heated distal portion of the pipe until the distal end of the distal portion of the pipe contacts a stop flange of the sleeve.

4. The method according to claim 2, wherein the reducing step comprises reducing the inner diameter of the pipe until the percentage of connection between the inner surface of the pipe and the outer surfaces of the diameter-expanded portion of the sleeve and the diameter-reduced cylindrical section of the sleeve is equal to or greater than 75%.

5. The method according to claim 4, wherein the percentage of connection is between 90% and 96%.

6. The method according to claim 1, wherein the step of removing the attached pipe and sleeve from the cylindrical rod of the mandrel is performed within 3 seconds after the arranging step.

7. The method according to claim 1, wherein the heating step comprises heating the heating body to a temperature between 250 degrees Celsius and 290 degrees Celsius.

8. The method according to claim 1, comprising the step of performing the arranging step within 10 seconds after the step of removing the distal portion.

9. The method according to claim 1, further comprising the step of holding the pipe by hand to perform the arranging step.

10. The method according to claim 1, comprising the step of performing the step of removing the attached pipe and sleeve within 10 seconds after the arranging step.

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