U.S. patent application number 10/708490 was filed with the patent office on 2004-08-05 for process for manufacture of plastic-lined metal-encased tubing segment connector system.
This patent application is currently assigned to MERCURY PLASTICS, INC.. Invention is credited to Rowley, William W..
Application Number | 20040150132 10/708490 |
Document ID | / |
Family ID | 32228822 |
Filed Date | 2004-08-05 |
United States Patent
Application |
20040150132 |
Kind Code |
A1 |
Rowley, William W. |
August 5, 2004 |
PROCESS FOR MANUFACTURE OF PLASTIC-LINED METAL-ENCASED TUBING
SEGMENT CONNECTOR SYSTEM
Abstract
The invention relates generally to a solderless
metallic-encased, polymeric-lined connector system.
Inventors: |
Rowley, William W.; (Chagrin
Falls, OH) |
Correspondence
Address: |
BUCKINGHAM, DOOLITTLE & BURROUGHS, LLP
50 S. MAIN STREET
AKRON
OH
44308
US
|
Assignee: |
MERCURY PLASTICS, INC.
15760 Madison Road
Middlefield
OH
|
Family ID: |
32228822 |
Appl. No.: |
10/708490 |
Filed: |
March 8, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10708490 |
Mar 8, 2004 |
|
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|
10286555 |
Nov 1, 2002 |
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Current U.S.
Class: |
264/150 ;
264/230; 264/573; 285/381.1 |
Current CPC
Class: |
F16L 33/30 20130101;
F16L 13/143 20130101 |
Class at
Publication: |
264/150 ;
285/381.1; 264/230; 264/573 |
International
Class: |
B29C 061/04 |
Claims
1. A process for fabricating which comprises the steps of: (a)
inserting a length of a polymeric tube having a polymeric tube
external diameter at least partially into a length of a metallic
tube having a metallic tube internal and external diameter, said
metallic tube internal diameter being larger than said polymeric
tube external diameter; and (b) reducing an external and internal
diameter of said metallic tube until said internal diameter of said
metallic tube is essentially equal to said external diameter of
said polymeric tube.
2. The process of claim 1 wherein said step of reducing is through
the application of an inwardly compressive circumferential force
about said metallic tube.
3. The process of claim 1 which further comprises the step of
extruding said polymeric tube prior to the step of inserting.
4. The process of claim 3 which further comprises the step of
cutting said polymeric tube to said length after said step of
extruding.
5. The process of claim 4 wherein said step of extruding comprises
a step of coextruding.
6. The process of claim 1 wherein said step of inserting comprises
fully inserting said length of said polymeric tube into said length
of said metallic tube.
7. A process for fabricating which comprises the steps of: (a)
reducing an outer diameter of at least a partially crosslinked
polymeric tube from a first outer diameter to a smaller second
outer diameter; (b) inserting a length of said at least a partially
crosslinked polymeric tube having a polymeric tube at least
partially into a length of a metallic tube having a metallic tube
internal and external diameter, said metallic tube internal
diameter being larger than said polymeric tube second outer
diameter and approximately equal to said first outer diameter of
said at least partially crosslinked polymeric tube; and (c) heating
said tubes so that said partially crosslinked polymeric tube
expands in diameter to approximate said first outer diameter.
8. The process of claim 7 wherein said at least partially
crosslinked polymeric tube is at least 50% crosslinked.
9. The process of claim 8 wherein said at least partially
crosslinked polymeric tube is at least 60% crosslinked.
10. The process of claim 9 wherein said at least partially
crosslinked polymeric tube is polyethylene.
11. The process of claim 10 wherein said polyethylene is fully
crosslinked.
12. The process of claim 7 which further comprises the step of
extruding said polymeric tube prior to the step of reducing.
13. The process of claim 12 which further comprises the step of
cutting said polymeric tube to said length after said step of
extruding.
14. The process of claim 12 wherein said step of extruding
comprises a step of coextruding.
15. The process of claim 7 wherein said step of inserting comprises
fully inserting said length of said polymeric tube into said length
of said metallic tube.
16. A process for fabricating which comprises the steps of: (a)
inserting a length of a polymeric tube having a polymeric tube
external diameter at least partially into a length of a metallic
tube having a metallic tube internal and external diameter, said
metallic tube internal diameter being larger than said polymeric
tube external diameter; and (b) sealing one end of said polymeric
tube; (c) heating said tubes to a temperature at which the
polymeric tube becomes processable; and (d) pressurizing said
polymeric tube with a sufficient degree of pressure to effect
radial expansion of said polymeric tube.
17. The process of claim 16 which further comprises the step of
extruding said polymeric tube prior to the step of inserting.
18. The process of claim 17 which further comprises the step of
cutting said polymeric tube to said length after said step of
extruding.
19. The process of claim 18 wherein said step of extruding
comprises a step of coextruding.
20. The process of claim 16 wherein said step of inserting
comprises fully inserting said length of said polymeric tube into
said length of said metallic tube.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from and is a division of
co-pending U.S. Ser. No. 10/286,555 filed Nov. 1, 2002
BACKGROUND OF INVENTION
[0002] The invention relates generally to a polymeric-lined,
metal-encased tubing segment connector system which eliminates the
need for soldering in order to connect the tubing segments.
[0003] In any environment, the need exists to be able to connect
fluid conduits and pipes of different diameters as well as tubing
and pipe fittings having different configurations and geometries.
While this is not a problem for an experienced plumber with a
working knowledge of standardized pipe and tubing sizes and
fittings, the challenge is more difficult for the homeowner or the
do-it-yourselfer. Additionally, while the experienced plumber is
familiar with the art of soldering copper pipe together in order to
achieve a leak-proof connection, this skill is often lacking with
many homeowners or do-it-yourselfers.
[0004] One alternative to copper tubing is rigid plastic tubing
(e.g., polyvinyl chloride or PVC), which is often used in water
drain lines. PVC adhesives are typically used to glue the tubing
segments to tubing connectors. It is also possible to connect
polymeric tubing by substituting flexible PVC and using a crimp
ring to compress the tubing ends deformably down against a rigid
insert positioned in the internal conduit in the tubes. This use of
crimp rings is particularly well known in association with
elastomeric hose or tubing, where the material possesses sufficient
elasticity to be deformed without breaking. When a connector having
a permanently formed feature in the internal conduit (such as a
bend, reducer or intersection) has been required, the prior art has
made these connectors out of metal, especially brass or copper, or
a rigid polymeric material, especially a thermoplastic. Therefore,
connectors may be shaped into an "L", "T" "Y", "X", reducing or
enlarging connectors of the above defined or other shapes,
inclusive of other shapes required of connectors in everyday tubing
applications.
[0005] Therefore, what has been lacking in the industry is a fluid
connector system which capitalizes on the ease of installation and
connection of lengths of polymeric tubing using crimp rings but
which sags excessively, with the professional look of copper
without the need for soldering copper connectors. The system of the
instant invention capitalizes on the best elements of both systems,
namely the professional look of copper installations with the ease
of connection of polymers using crimp rings. This is an advantage
provided by the present invention.
SUMMARY OF INVENTION
[0006] The invention is directed to a polymeric-lined
metal-encased, preferably copper, tube segment connector system
which eliminates the need for copper soldering to effect the
leak-proof engagement between tubing segments. In one embodiment,
the connector comprises a central portion with an internal conduit
having a permanently formed feature therein, and a plurality of
arms. Each of the arms extends from the central portion and
terminates in an arm end, such that there is one arm and arm end
paired with each of the tube ends, with the connector internal
conduit extending through the arms to the respective arm ends. A
first nipple portion of each linear insert has an external surface
frictionally engaged in an internal surface of the connector
internal conduit at the arm end. A second nipple portion of each
linear insert has an external surface frictionally engaged in an
internal surface of the polymeric-lined tube internal conduit at
the tube end. The plurality of ring members are such that one ring
member is slidingly received along each tube end or arm end atop
one of the linear inserts frictionally engaged therein, the ring
member compressively deforming the respective tube end or arm end
onto the linear insert, joining the connector internal conduit to
the tube internal conduit in a leak-free manner.
[0007] In a second embodiment, the linear insert and connector are
of unitary construction, each connector having a protruding nipple
portion with an external surface frictionally engaged in an
internal surface of the polymeric-lined tube internal conduit at
the tube end. The plurality of ring members are such that one ring
member is slidingly received along each tube end or arm end atop
one of the protruding nipples frictionally engaged therein, the
ring member compressively deforming the respective tube end or arm
end onto the nipple, joining the connector internal to the tube
internal conduit in a leak-free manner. In an alternative
embodiment, when the connector nipples are sufficiently long, it is
possible to effect the crimp sealing of the connector and tubing
without the need for crimp rings, which are then optional.
[0008] In one principal aspect of the present invention, the
invention capitalizes on the flexibility of plastics and polymers
to effect the sealing engagement with a metal or thermoset
connector with the rigidity of copper tubing.
[0009] In another principal aspect of the present invention to
eliminate the inherent "sagging" of an all-plastic connector
system.
[0010] Accordingly, it is an object of the present invention to
eliminate the need for soldering when connecting lengths of copper
tubing.
[0011] It is another object of the present invention to provide a
system which uses the inherent flexibility of thermoplastics and
some thermosets with the rigidity of copper tubing.
[0012] It is still another object of the present invention to
provide a system which facilitates the fabrication of manifold
connections which are now less labor-intensive and form the basis
of a cross-over product which combines the best features of metal
and polymers.
[0013] These and other advantages of the present invention are
provided by the present invention, which comprises a tubing
assembly, comprising at least two polymer-lined metal tubes, a
metal tubing connector, and a plurality of crimp ring members. Each
polymeric-lined tube has a tube end and an internal conduit. A
connector, typically metal, is for joining the at least two
tubes.
[0014] In the preferred embodiments, the permanently formed feature
of the connector is selected from the group consisting of an
angular diversion, an intersecting conduit, a smooth reduction of
the internal and external diameters, and any combination
thereof.
[0015] In the preferred embodiments, the connector is metal,
preferably copper.
[0016] In some embodiments, the connector will have two arms. In
other embodiments, it will have three arms, especially arranged in
a "T" shape or a "Y" shape. In other embodiments, the connector has
four or more arms.
[0017] In some embodiments, at least one of the at least two tubes
is an arm of a further connector.
[0018] In some embodiments, the connector is a linear reducer. In
other embodiments, the connector is a reducing elbow.
[0019] These and other objects of the present invention will become
more readily apparent from a reading of the following detailed
description taken in conjunction with the accompanying drawings
wherein like reference numerals indicate similar parts, and with
further reference to the appended claims.
BRIEF DESCRIPTION OF DRAWINGS
[0020] The invention may take physical form in certain parts and
arrangements of parts, a preferred embodiment of which will be
described in detail in the specification and illustrated in the
accompanying drawings which form a part hereof, and wherein:
[0021] FIG. 1 shows an exploded view of a polymeric-lined tubing
assembly being connected using a linear multi-ribbed metal
connector;
[0022] FIG. 2 shows an exploded view of a tubing assembly of the
present invention using two multi-ribbed connectors of FIG. 1;
[0023] FIG. 3 shows an alternative embodiment of a tubing assembly
of the present invention using a one-piece multi-ribbed metallic
connector;
[0024] FIG. 4 shows an enlarged cross-sectional view of one
polymeric-lined metal-encased tubing segment taken along line 4-4
of FIG. 3;
[0025] FIG. 5 shows an alternative embodiment of a tubing assembly
of the present invention using a one-piece multi-ribbed metallic
connector with an expanded nipple section for use without crimp
rings;
[0026] FIG. 6 shows an enlarged cross-sectional view of an
alternative embodiment of the polymeric-lined metal-encased tubing
segment showing a coextruded polymer tube;
[0027] FIG. 7 shows a three-armed "T" connector;
[0028] FIG. 8 shows a three-armed "Y" connector;
[0029] FIG. 9 shows a four-armed "X" connector;
[0030] FIG. 10 shows a two-armed elbow;
[0031] FIG. 11 shows a two-armed reducing elbow;
[0032] FIG. 12 shows a linear reducer;
[0033] FIG. 13 shows an side elevational view of a portion of a
connector system wherein the polymer has a visible colorant
disposed therein;
[0034] FIG. 14 shows a side elevational view of a portion of a
connector system wherein the polymer has a colorant which is not
visible under visible light illumination; and
[0035] FIG. 15 shows a side elevational view of a portion of a
connector system wherein the polymer has a colorant which is
visible under non-visible light illumination.
DETAILED DESCRIPTION
[0036] Referring now to the drawings wherein the showings are for
purposes of illustrating the preferred embodiment of the invention
only and not for purposes of limiting the same, FIG. 1 shows two
segments of a metal-encased polymeric-lined tubing assembly 10
which is in leak-proof fluid communication with a linear connector
20. The assembly 10 comprises first and second essentially straight
tubes 12, 14, each of which has at least one tube end 16, which
provides access to an internal conduit 42 in each tube 12, 14. Each
tube 12, 14 is comprised of two components: a metal exterior 34
having an internal diameter 18; and a polymer tube 36 centrally
disposed therein having an internal diameter 38. In the most common
cases, the internal conduit 42 defined by internal diameter 38 will
be smooth and otherwise unremarkable. For each of the tubes 12, 14,
there will be an inner and outer diameter, an outer diameter of the
polymeric tube 36 being essentially equal to the internal diameter
of metal tube 34. The differences between the inner and outer
diameters of the polymer and metal tubes representing a wall
thickness for each tube.
[0037] An insert 20 shown in its linear configuration in FIG. 1, is
used to connect the tube ends 16 of tubes 12,14. The particular
insert 20 shown in FIG. 1 has a central bulbous portion 22, with
identical first and second nipple portions 24a, 24b extending away
from the bulbous portion. Other inserts 20, not shown, would have
one nipple portion 24 with a larger diameter than the other or have
the two nipple portions 24 aligned at an angle to each other as
better illustrated in FIGS. 2, 3 and 5. The exterior surface of the
nipple portions 24a, 24b will generally be provided with at least
one circumferential rib 26 of slightly larger diameter and the
distal end 28 of each nipple portion will generally have a collar
40 of even a slightly larger diameter, said collar illustrated only
in FIG. 2. The interior surface 44 of the insert 20 is generally
smooth and otherwise unremarkable. The nipple portion 24a or 24b
may be inserted into the tube end 16 in a slight interference fit
due to the external diameter of the ribs 26 and optional collar 40.
This slight interference fit will retain the insert 20 loosely in
the tube end 16, although it may be removed easily if desired. The
central bulbous portion 22, has a larger external diameter than the
internal diameter of the tubes 12, 14 at tube end 16, and provides
a stop when it abuts against the tube end 16.
[0038] FIG. 2 shows the present invention and is illustrative of
this concept where it shows insert 20 inserted into 90.degree.
connector 112 at connector end 116. A crimp ring 30 for a
particular fitting is characterized by two specific dimensions. An
internal diameter of the ring 30 is sufficiently larger than the
external diameter of the tubes 12, 14 so that the ring will
generally slide freely along the length of the tube. The ring 30
will have a external diameter effectively defined by the desired
wall thickness and the internal diameter. The ring 30 will have an
axial length 32 long enough to provide an ample surface for
applying a crimping tool, but preferably not longer than a distance
between the central bulbous portion 22 and the distal end 28 or
optional collar 40 on the insert 20. This fit is illustrated in
FIGS. 1 and 2, where a present invention connector end 116 is
involved. When the ring 30 and insert 20 are properly positioned on
a tube end 16 and the internal diameter of the ring is reduced by
deformation from a crimping tool or the like, the ring, the tube
end 16 is compressively deformed onto the nipple portion 24,
effectively securing the proximal end 28 or optional collar 40
within the tube end 16 with leakproof engagement effected by
intimate surface contact of the interior surfaces of polymeric tube
36 with the exterior surface of one nipple 24 of the linear
connector 20.
[0039] When properly assembled, a slight amount (approximately 1/8
inch) of the tube end 16 beyond the ring 30 is exposed, as is
generally shown on tube end 16 of tube 14 in FIG. 1. A properly
assembled crimp ring/tube/fitting assembly will withstand
considerable internal pressure and provides an attractive method of
attaching tubing pieces together. Both the crimp ring 30 and the
insert 20 will be preferably formed from a metal such as copper or
brass, although it is possible to use a rigid plastic material,
especially a thermoplastic, for the insert and it is known in the
art to use a crimp ring 30 which is polymeric. In this latter case,
the crimp ring 30 as a normal or relaxed internal diameter which is
smaller than the external diameter of the tube end 16. Such a
polymeric ring 30 can have its internal diameter temporarily
expanded with an expander tool and the ring can be placed on the
tube end 16 while in this expanded state. As the polymer relaxes
back to its smaller internal diameter, the compressive force
exerted on the tube end 16 deforms the tube end onto the
corresponding nipple portion 24.
[0040] From the foregoing description, it will be understood that
the same tube joining technique shown at tubes ends 16 of tubes 12,
14 could be performed at a second end of either one of the tubes
12, 14, in which case a short straight length of the tube connected
at each end to the other tubes would effectively define a connector
having arm ends where ring members 30 would compressively deform
the arm ends onto the insert 20, joining an internal conduit 44 in
the connector to the internal conduit 42 in the tubes in a
leak-free manner. However, the invention is not limited to linear
connectors, but is also applicable to connectors possessing a
permanently formed feature, such as an angular diversion of the
connector internal conduit, an intersection or a reduction of
diameter, while retaining the ability to join the connector to the
tubes in a leak-free manner by compressively deforming the arm ends
of the connector onto an insert 20.
[0041] In FIG. 2, the angularity discussed previously is
illustrated showing one embodiment of a tubing assembly 110 of the
present invention. In a preferred embodiment, crosslinkable
polyethylene, commonly referred to as "PEX", is a preferred
material, but other materials possessing the required properties
may allow practice of the present invention. For example, it may be
possible to obtain the inventive effect with polypropylene,
commonly referred to as "PP". PEX may be extruded into tubes while
in an uncrosslinked condition, during which it acts as a
thermoplastic. The extruded tube may be formed into shapes and then
crosslinked, using a variety of known crosslinking techniques, to
permanently set the shapes into the PEX tube, which retains a
sufficient amount of elasticity to be deformably compressed between
a crimp ring and an insert to provide a leak-free seal. The PEX
material may also be injection molded from a melt in an effectively
uncrosslinked condition in conventional molding equipment to impart
a shape to the connector formed, which is then permanently set by
crosslinking, again by conventional techniques. By "effectively
uncrosslinked", we recognize that the very act of molding the
material will result in some small amount of crosslinking, but that
the final and critical crosslinking occurs after the material has
been formed into the final desired shape. Additional aspects of the
preferred embodiment of the invention may be imparted to the
connector being formed during the shaping process, as will be
discussed in more detail below.
[0042] In FIG. 2, the tubing assembly 110 of the present invention
is shown with a "L" shape connector 112 being substituted for the
prior art linear connector 20 shown in FIG. 1. While the "L" shape
shown is a two-ended version of a connector 112 useful in the
present invention, there are many other known shapes which can be
molded using the technique described above, including the
three-ended connectors generally referred to as "T" or "Y"
connectors, and the four-ended connector known as a "cross" or an
"X." Although not commonly used, it is certainly possible to have
more than four ends on connector 112. In the preferred embodiments,
the connector 112 will be sized to match the internal and external
diameters of the tubing with which it will be used, thereby
allowing a symmetrical insert 20 and the same size crimp ring 30 to
be used on both sides of the connection. The most commonly
encountered sizes of tubes with which this invention is anticipated
as being used are the nominal 1/2-inch and 3/4-inch internal
diameter tubes, although the invention is certainly not limited to
those sizes and smaller sizes such as 3/8-inch and larger sizes
such as 1-inch are included as are small and larger specialty
sizes.
[0043] The connector 112 which is used in the present invention for
joining at least two tubes 12,14 will have a central portion 124
and a plurality of arm ends 116, one such arm end at a distal end
of each of a plurality of arms 120. The arms 120 have a proximal
end 116 integral with the central portion 124. Typically, one arm
end 116 will be paired with each tube end 16 of the tubes (such as
12,14 in FIG. 2) to be joined in the assembly 110. The connector
112 has an internal conduit 124 having an inner diameter 122
defined by inner walls 118 communicating with the arm ends 116,
such that the internal conduit in the central portion 124 has a
permanently formed feature 114 therein. In the particular case
shown with an "L" connector, the permanently formed feature 114 is
the 90.degree. bend in the internal conduit 124. Clearly, the other
connectors are within the scope of the invention and may have a
different permanently formed feature. Once the connector 112 is
provided, FIG. 2 shows that the tubing assembly 110 may be formed
through exactly the same joining process taught with respect to
FIG. 1.
[0044] FIG. 3 illustrates yet another embodiment of this invention
which once again includes a permanently formed feature 160, showing
a 90.degree. bend between each respective arm 164 of connector 158.
In this configuration, which eliminates the need for two crimp
rings 30, nipples 168 are integrally formed thereupon each
connector arm 164. Each nipple 168 has a radially expanded bulbous
portion 152 with a plurality of radially expanded ribs 154
terminating at terminal end 156. The connector 158 has an internal
conduit having an inner diameter 162 defined by inner walls 166
communicating with the terminal ends 156. The connector system 150
achieves leak-proof engagement of tube arms 12,14, by radial
compression of crimp rings 30 about an exterior surface of metal
tube 34 which effects corresponding radial compression of inner
diameter 38 of polymeric tube 36 to come into frictional contact
with a nipple 168 of an arm 164 of connector 158.
[0045] FIG. 4 illustrates a cross-section of one arm of the system
illustrating the outer metal tube 34 with polymeric tube 36
essentially centrally disposed therein, said inner diameter 38 of
the polymeric tube defining a hollow conduit 42. While the tube
within a tube is shown to have an essentially frictional fit
between the inner and outer tubes, it is possible to have a small
gap between the tubes to facilitate insertion of the inner tube. In
an alternative embodiment of the invention illustrated in FIG. 6,
the polymeric tube is comprised of two polymers, a first outer
polymer 36 and a second inner polymer 46 defining a hollow conduit
42. In a preferred embodiment, the polymers which comprise the
first and second polymers are coextruded, although this is not
essential. The value in having two polymers, preferably of
different composition, is that it is possible to maximize the
barrier characteristics of the polymers. In one embodiment, the
polymer combination could be crosslinked polyethylene for one
polymer and polyethylenevinyl alcohol as the barrier polymer. Using
this combination is valuable in that applications such as
refrigeration hosing, as may be used for example to air
conditioning units, may be replaced using this combination system
replacing hoses which have rubber on the outside. Additionally, the
insulation properties may be superior to the use of one
polymer.
[0046] FIG. 5 illustrates yet another embodiment of the invention
which eliminates the need for a crimp ring 30. In this embodiment,
each nipple 168 is axially extended so as to permit a crimping tool
to compressively deform an outer surface of the metallic tube 34
with corresponding compression deformation of an inner polymeric
tube 36 effecting leak-proof contact of an inner side of said
polymeric tube with an exterior side of said connector 158. When
used without crimp rings, it is preferred to utilize at least two
compressive deformations to insure leak-proof engagement between
the inner polymeric tube with the nipples on the connector.
[0047] FIG. 7 illustrates yet another embodiment of the invention
illustrating a "T" connector 60 connecting three tube arms 12, 12a,
14 with crimp rings 30 in compressive contact with the arms and
ribs 26. FIG. 8 is an embodiment similar to FIG. 7 illustrating a
"Y" connector 70 once again connecting three arms as described
previously. FIG. 9 illustrates an "X" connector 80 connecting
opposed tube arms 12, 12a as well as 14, 14a in an analogous
manner. FIG. 10 illustrates an elbow connector 90 having opposed
ends 92 bent at approximately 90.degree. with a plurality of ribs
26 which are used to fasten tube arms 12, 14 via crimp rings 30.
FIG. 11 is a view similar to FIG. 10 wherein the elbow is a
reducing elbow 90a in which approximately 90.degree. bent ends 92,
92a are of different diameters, thereby requiring a smaller
diametered crimp ring 29 in compressive engagement with smaller
diametered tube arm 11 in comparison to crimp ring 30 in
compressive engagement with larger diametered tube arm 12. FIG. 12
is an example of a linear reducer 100 in which the connector has a
larger end 102 and a smaller diametered end 101. As described in
relationship to FIG. 11, a smaller diameter crimp ring 29 is in
compressive engagement with the smaller diametered tube arm 11
while the larger diametered crimp ring 30 is in compressive
engagement with the larger diametered tube arm 12.
[0048] While only a few polymers have been mentioned, the present
invention is applicable to a wide variety of polymers, either
singly or in combination, including polyolefins, polycarbonates,
polyesters, polyurethanes, polyalkylene terephthalates,
polysulfones, polyimides, polyphenylene ethers, styrenic polymers,
polycarbonates, acrylic polymers, polyamides, polyacetals, halide
containing polymers and polyolefin homopolymers and copolymers.
Additionally included would be mixtures of different polymers, such
as polyphenylene ether/styrenic resin blends, polyvinylchloride/ABS
or other impact modified polymers, such as methacrylonitrile
containing ABS, and polyester/ABS or polyester plus some other
impact modifier may also be used. Such polymers are available
commercially or may be made by means well known in the art.
[0049] More specifically, polymers of monoolefins and diolefins,
for example would include polypropylene, polyisobutylene,
polybutene-1, polymethylpentene-1, polyisoprene or polybutadiene,
as well as polymers of cycloolefins, for instance of cyclopentene
or norbornene, polyethylene (which optionally can be crosslinked),
for example high density polyethylene (HDPE), low density
polyethylene (LDPE) and linear low density polyethylene (LLDPE) may
be used. Mixtures of these polymers, for example mixtures of
polypropylene with polyisobutylene, polypropylene with polyethylene
(for example PP/HDPE), may also be used. Also useful are copolymers
of monoolefins and diolefins with each other or with other vinyl
monomers, such as, for example, ethylene/propylene, LLDPE and its
mixtures with LDPE, propylene/butene-1, ethylene/hexene,
ethylene/ethylpentene, ethylene/heptene, ethylene/octene,
propylene/butadiene, isobutylene/isoprene, ethylene/alkyl
acrylates, ethylene/alkyl methacrylates, ethylene/vinyl acetate
(EVA) or ethylene/acrylic acid copolymers (EAA) and their salts
(ionomers) and terpolymers of ethylene with propylene and a diene,
such as hexadiene, dicyclopentadiene or ethylidene-norbornene; as
well as mixtures of such copolymers and their mixtures with
polymers mentioned above, for example
polypropylene/ethylene-propylene copolymers, LDPE/EVA, LDPE/EAA,
LLDPE/EVA and LLDPE/EAA.
[0050] Thermoplastic polymers may also include styrenic polymers,
such as polystyrene, poly-(p-methylstyrene),
poly-(.alpha.-methylstyrene), copolymers of styrene or
.alpha.-methylstyrene with dienes or acrylic derivatives, such as,
for example, styrene/butadiene, styrene/acrylonitrile,
styrene/alkyl methacrylate, styrene/maleic anhydride,
styrene/butadiene/ethyl acrylate, styrene/acrylonitrile/methac-
rylate; mixtures of high impact strength from styrene copolymers
and another polymer, such as, for example, from a polyacrylate, a
diene polymer or an ethylene/propylene/diene terpolymer; and block
copolymers of styrene, such as, for example,
styrene/butadiene/styrene, styrene/isoprene/styrene,
styrene/ethylene/butylene/styrene or
styrene/ethylene/propylene/styrene. Styrenic polymers may
additionally or alternatively include graft copolymers of styrene
or .alpha.-methylstyrene such as, for example, styrene on
polybutadiene, styrene on polybutadiene-styrene or
polybutadine-acrylonitrile; styrene and acrylonitrile (or
methacrylonitrile) on polybutadiene; styrene and maleic anhydride
or maleimide on polybutadiene; styrene, acrylonitrile and maleic
anhydride or maleimide on polybutadiene; styrene, acrylonitrile and
methyl methacrylate on polybutadiene, styrene and alkyl acrylates
or methacrylates on polybutadiene, styrene and acrylonitrile on
ethylene/propylene/diene terpolymers, styrene and acrylonitrile on
polyacrylates or polymethacrylates, styrene and acrylonitrile on
acrylate/butadiene copolymers, as well as mixtures of with the
styrenic copolymers indicated above.
[0051] Nitrile polymers are also useful in the polymer composition
of the invention. These include homopolymers and copolymers of
acrylonitrile and its analogs such as methacrylonitrile, such as
polyacrylonitrile, acrylonitrile/butadiene polymers,
acrylonitrile/alkyl acrylate polymers, acrylonitrile/alkyl
methacrylate/butadiene polymers, acrylonitrile/butadiene/styrene
(ABS), and ABS which includes methacrylonitrile.
[0052] Polymers based on acrylic acids, include acrylic acid,
methacrylic acid, methyl methacrylate acid and ethacrylic acid and
esters thereof may also be used. Such polymers include
polymethylmethacrylate, and ABS-type graft copolymers wherein all
or part of the acrylonitrile-type monomer has been replaced by an
acrylic acid ester or an acrylic acid amide. Polymers including
other acrylic-type monomers, such as acrolein, methacrolein,
acrylamide and methacrylamide may also be used.
[0053] Halogen-containing polymers may also be useful. These
include resins such as polychloroprene, epichlorohydrin
homopolymers and copolymers, polyvinyl chloride, polyvinyl bromide,
polyvinyl fluoride, polyvinylidene chloride, chlorinated
polyethylene, chlorinated polypropylene, fluorinated
polyvinylidene, brominated polyethylene, chlorinated rubber, vinyl
chloride-vinylacetate copolymer, vinyl chloride-ethylene copolymer,
vinyl chloride-propylene copolymer, vinyl chloride-styrene
copolymer, vinyl chloride-isobutylene copolymer, vinyl
chloride-vinylidene chloride copolymer, vinyl
chloride-styrene-maleic anhydride tercopolymer, vinyl
chloride-styrene-acrylonitrile copolymer, vinyl chloride-isoprene
copolymer, vinyl chloride-chlorinated propylene copolymer, vinyl
chloride-vinylidene chloride-vinyl acetate tercopolymer, vinyl
chloride-acrylic acid ester copolymers, vinyl chloride-maleic acid
ester copolymers, vinyl chloride-methacrylic acid ester copolymers,
vinyl chloride-acrylonitrile copolymer and internally plasticized
polyvinyl chloride.
[0054] Other useful thermoplastic polymers include homopolymers and
copolymers of cyclic ethers, such as polyalkylene glycols,
polyethylene oxide, polypropylene oxide or copolymers thereof with
bis-glycidyl ethers; polyacetals, such as polyoxymethylene and
those polyoxymethylene with contain ethylene oxide as a comonomer;
polyacetals modified with thermoplastic polyurethanes, acrylates or
methacrylonitrile containing ABS; polyphenylene oxides and
sulfides, and mixtures of polyphenylene oxides with polystyrene or
polyamides; polycarbonates and polyester-carbonates; polysulfones,
polyethersulfones and polyetherketones; and polyesters which are
derived from dicarboxylic acid and diols and/or from
hydroxycarboxylic acids or the corresponding lactones, such as
polyethylene terephthalate, polybutylene terephthalate,
poly-1,4-dimethyliol-cyclohexane terephthalate,
poly-[2,2,4-(4-hydroxyphe- nyl)-propane]terephthalate and
polyhydroxybenzoates as well as block copolyetheresters derived
from polyethers having hydroxyl end groups.
[0055] Polyamides and copolyamides which are derived from diamines
and dicarboxylic acids and/or from aminocarboxylic acids or the
corresponding lactams, such as polyamide-4, polyamide-6,
polyamide-6/6, polyamide-6/10, polyamide-6/9, polyamide-6/12,
polyamide-4/6, polyamide-11, polyamide-12, aromatic polyamides
obtained by condensation of m-xylene, diamine and adipic acid;
polyamides prepared from hexamethylene diamine and isophthalic
and/or terephthalic acid and optionally an elastomer as modifier,
for example, poly-2,4,4-trimethylhexamethylene terephthalamide or
poly-m-phenylene isophthalamide may be useful. Further copolymers
of the aforementioned polyamides with polyolefins, olefin
copolymers, ionomers or chemically bonded or grafted elastomers; or
with polyethers, such as for instance, with polyethylene glycol,
polypropylene glycol or polytetramethylene glycols, and polyamides
or copolyamides modified with EPDM or ABS may be used.
[0056] While copper is the preferred metal for the outer metallic
tube 34, it is recognized that the invention is not limited to the
same, and that any metal is useful in the invention, e.g., steel,
aluminum, chrome-plated copper, etc.
[0057] In yet another embodiment of this invention illustrated in
FIGS. 13-15, each of said inner polymeric tubes is color coded at
least at an end, and often throughout the polymer, to permit
identification of either a "hot" or a "cold" water line. This color
coding is effected by either the incorporation of a colorant into
the polymer during the extrusion process, or as purchased from a
supplier already blended therein. Said colorant is typically
visible under normal conditions of illumination as shown in FIG. 13
wherein inner polymeric tube is illustrated to be blue 36a while
the same inner polymeric tube is also indicated to be red 36b for
distinguishing between "cold" and "hot" water lines respectively,
or may be invisible and only detectable by exposure to ultraviolet
light or other light from other ranges of the wavelength spectrum,
for example, see FIGS. 14-15 wherein inner polymeric tubes 36c, 36d
are illustrated to be non-colored when exposed to visible light
(FIG. 14) while the same inner polymeric tubes are illustrated to
be blue and red respectively when exposed to ultraviolet light
(FIG. 15). It is preferable to have the polymeric tubes color coded
with widely different colors, e.g., blue or black for cold water,
and red or orange for hot water. This color coding, which is
visible by looking at an end of the metal-encased, polymer-lined
tubing, is an effective way to minimize cross linking of hot and
cold water pathways. In one embodiment, the colorant is a
fluorescing pigment or dye which is added into the polymer which
emits a defined wavelength of light from the electromagnetic
spectrum upon excitation by an appropriate wavelength of incident
light.
[0058] It is understood that due to the higher temperatures
experienced with hot water, the polymeric inner tube is often a
thermoset and often is a crosslinked polymer to increase the heat
stability of the polymer. This increased heat stability is often
not necessary with cold water pathways.
[0059] By having a large polymeric surface area in intimate contact
with either a nipple of an insert or with a nipple of the
connector, it is possible to eliminate the need for any "O-rings,"
non-limiting examples of said rings including EPDM
(ethylene-propylene diene monomer), VITON, BUNA-N or neoprene.
[0060] In a preferred embodiment, the polymers will have an
antioxidant or metal deactivator, such as is commercially available
from a variety of sources. In particular, non-limiting exemplary
antioxidants useful in the practice of this invention include the
following.
1 Chemical Name Chemical Formula pentaerythritol tetrakis(3-(3,5-
di-tert-butyl-4- hydroxyphenyl)propionat- e 1 thiodiethylene
bis[3,5-di-tert- butyl-4- hydroxyphenyl)propionate] 2
octadecyl-3-(3,5-di-tert-buty- l- 4-hydroxyphenyl)-propionate 3
6,6'-di-tert-butyl-2,2'-t- hiodi-p- cresol 4
N-N'-hexane-1,6-diylbis(3- (3,5-di-tert-butyl-4-
hydroxyphenylpropionamide)) 5 benzenepropanoic acid, 3,5-
bis(1,1-dimethyl-ethyl)-4- hydroxy-.C.sub.7-C.sub.9 branched alkyl
esters 6 mixture of phenol, 2,4- dimethyl-6-(1- methylpentadecyl)
and octdecyl-3-(3,5-di-tert-butyl- 4-hydroxy-phenyl)-propionate 7
3,3',3',5,5',5'-hexa-tert-butyl- a,a',a'-(mesitylene-2,4,6-
triyl)tri-p-cresol) 8 calcium diethyl bis(((3,5-
bis(1,1-dimethylethyl)-4- hydroxyphenyl)methyl) phosphonate) 9
4,6-bis(octylthiomethyl)-o- cresol 10 hexamethylene bis(3-(3,5-di-
tert-butyl-4-hydroxyphenyl) propionate) 11
2-(1,1-dimethyl)-6-[3-(1,1- dimethylethyl)-2-hydroxy-5-
methylphenyl]methyl-4- methylphenyl acrylate 12
1,3,5-tris(3,5-di-tert-butyl-4- hydroxybenzyl)-1,3,5-triazine-
2,4,6(1H,3H,5H)-trione 13 (2,4,6-trioxo-1,3,5-triazine-
1,3,5(2H,4H,6H)- triyl)triethylene tris(3-(3,5-di- tert-butyl-4-
hydroxyphenyl)propionate) 14 2,2'-oxidobis[ethyl 3-(3,5-di-
tert-butyl-4- hydroxyphenyl)propionate] 15 mixture of 2-(1-
methylpropyl)-4,6- dinitrophenol and N-(1,4-
dimethylpentyl)-N'-phenyl- 1,4-benzenediamine 16
4-methyl-2,6-bis(2- phenylethenyl) phenol 17
bis[(3,5-di-tert-butyl-4- hydroxyphenyl)propionyl-2- oxyethyl]
sulfide 18 tris(2,4-di-tert-butylphenyl) phosphite 19
2,2,4-trimethyl-1,2- dihydroquinoline polymer 20 tris(nonylphenyl)
phosphite 21 4-(1-methyl-1-phenylethyl)- -N- [4-(1-methyl-1-
phenylethyl)phenyl]- benzeneamine 22 tetrakis(3,5-di-tert-butyl-4-
hydroxyhydrocinnamate) pentaerythritol 23 2,6-di-tert-butyl-4-
(octadecanoxycarbonylethyl) phenol 24 distearyl 3,3'-
thiodiopropionate 25 2,6-di-tert-butyl-p-cresol 26
N-isopropyl-N'-phenyl-1,4- phenylenediamine 27
p-(p-tolylsulfonylamido) diphenylamine 28 N-phenyl-1-naphthylamine
29 1,4-dihydroxy-2,5-di-tert- butyl benzene 30 diphenyl-p-phenylene
diamine 31 bis(2,4-di- cumylphenyl)pentaerythritol diphosphite 32
tris(3,5-di-tert-butyl-4- hydroxybenzyl) isocyanurate 33
bis(2,4-di-tert- butylphenyl)pentaerythritol diphosphite 34
distearyl pentaerythritol diphosphite 35
2,4,6-tri-tert-butylphenyl-2- butyl-2-ethyl-1,3-propanediol
phosphite 36 2,2',2"-nitrilo[triethyl tris
3,3',5,5'-tetra-tert-butyl- 1,1'biphenyl-2,2'-diyl) phosphite]
37
[0061] In fabrication of the polymer-lined, metal-encased tubing
segment connector system, it is often desirable to have the polymer
tube having an outer diameter which is smaller than an inner
diameter of the metal tube. With this particular geometry, it is
possible to quickly insert fairly long lengths of polymer tubing
into the metal tubing without undue pressure or snagging.
Subsequent to insertion, and in a most highly desirable mode, the
outer metal tubing is subjected to an inwardly compressive
circumferential force ("swaging") which narrows both the outer and
inner diameters of the metallic tubing so as to snugly fit the
inner diameter of the metallic tubing about the outer diameter of
the polymer tubing.
[0062] Alternatively, the tube within a tube could be formed by
sliding at least a partially crosslinked polymer, which has been
drawn down, i.e. which has been reduced in O.D., so that the O.D.
of the polymer tube is less than the I.D. of the metallic tube,
followed by subsequent reheating of the polymer tube, the reheating
capitalizing on the memory of a drawn down crosslinked material to
return to its original dimension and fill the cavity of the metal
tube. Specifically, at least partially crosslinked polymer, at
least 50%, more preferably 60%, most preferably fully crosslinked,
is reduced in outer diameter through a drawing operation with heat
and a die wherein the heated tube is run through a die to make the
outer diameter smaller than its original extruded dimension. This
tubing is then inserted into the metallic tube, preferably copper,
wherein the two tubes are reheated and the memory of crosslinked
polymers, particularly polyethylene, expands to its original
dimension which is essentially equivalent to the internal diameter
of the metallic tube. Utilization of this process allows the easy
and economic manufacture of this tube within a tube by facile
insertion and memory expansion. By using crosslinked polyethylene,
it is possible to use the "no stick" feature of crosslinked
polyethylene tubing since it will not tack off during the drawing
process should the internal diameter of the tube collapse at any
point. Normal materials would tack off as soon as they touch and
that would make the drawing and inserting operation much more
critical. This new route has a higher degree of tolerance in the
manufacturing process.
[0063] Still another alternative method for forming the tube within
a tube is to use "air-core" molding in which a polymer tube (either
crosslinked or non-crosslinked) is inserted into the metallic tube,
followed by sealing one end of the polymeric tube. This sealing may
be effected by crimping, heat sealing, insertion of a sealing
means, e.g., stopper, or by any other means known in the art,
followed by heating to a temperature at which the polymeric tube
becomes processable. It is recognized that the sealing and/or
heating steps may be interchanged at the preference of the user. At
this processable temperature, a pressurizing means (e.g.,
compressed gas) is used to radially expand the inner polymer tube
to contact the inner wall of the metal tube.
[0064] While in a preferred embodiment, the length of the inner
polymeric tube will be essentially equal to that of the outer
metallic tube, there is no need to limit the invention to such
equivalent dimensions. In an alternative embodiment, the inner
polymer tube is located at either end, and penetrates only to the
extent necessary to effect leak-proof connection with an inserted
connector. It is additionally recognized that in one embodiment of
this invention, the inner polymeric tube will be positioned at only
one end of the metallic tube and partially penetrate thereinto
while an opposed second end could be fastened to a connector by any
traditional manner.
[0065] It is equally understood that thickness of either the inner
or outer tubes plays essentially a limited role in the invention.
The combination of the thickness of the two tubes must be
sufficient to withstand recognized plumbing standards for burst
strength, but it is recognized that this may be effected in various
ways. The inner polymeric liner could be made relatively thick when
a polymer having relatively little structural integrity is used or
could be made relatively thin when a polymer having high structural
integrity is used. Additionally, in light of the fact that in a
preferred embodiment, the metallic outer tube is supplemented with
an inner tube, the thickness of the metal tube can be relatively
thinner than normal, although it does not have to be. In general,
the thickness of the polymer can be as low as approximately 30
thousands of an inch or as high as approximately one-quarter of an
inch thick. The thickness of the metallic tube can be as low as
approximately 70 thousands of an inch or as high as approximately
one-quarter of an inch thick and combinations therebetween. There
are essentially no practical limits on the hardness of the metallic
tubes, particularly copper.
[0066] It should also be noted that as an alternative to a
relatively snug-fitting relationship between the inner and outer
tubes, or as a supplement to when the two tubes are snugly fit, it
is recognized that it is possible to periodically or sporadically
disform the exterior metallic tube to as to minimize or prohibit
sliding of the inner tube within the outer tube. This disforming
can take many shapes, non-limiting examples including crimping,
pinching, bending, etc.
[0067] This invention has been described in detail with reference
to specific embodiments thereof, including the respective best
modes for carrying out each embodiment. It shall be understood that
these illustrations are by way of example and not by way of
limitation. Accordingly, the scope and content of the present
invention are to be defined only by the terms of the appended
claims.
* * * * *