Note: Descriptions are shown in the official language in which they were submitted.
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Field of the Invention
The present invention relates to the attainment of
nondetachable connections of thin-walled pipes or conduits used,
by way of example, for conveying corrosive liquids and, in
particular, to a press fit connector for nondetachably coupling
such conduits.
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Backqround of the Invention
ln the conveyance of corrosive liquids -- such, for
example, as sea water or thermal (i.e. high or elevated
temperature) water -- as in plumbing and the like, high demands
are made on the corrosion resistance of the liquid-conveying or
transporting conduits due, for example, to components such as
chlorides in the water. In order to overcome this problem,
stainless steels are frequently used in the fabrication of the
conduits. Despite their high alloy contents, stainless steels do
have practical limitations; thus, if the chloride content of the
liquid exceeds certain values, high alloy stainless steels will
also corrode and fail.
One solution to this problem in the transport of such
corrosive liquids lies in the use of titanium or of a titanium
alloy in fabricating the conduit, these materials being highly
corrosion-resistant and having a low specific gravity. Yet
titanium has heretofore been employed to only a limited extent in
conduits intended to convey, for example, sea water or thermal
water because the presently utilized technique for joining
sections of pipe formed of or containing titanium -- i.e. inert
gas welding -- represents a highly specialized and notably
expensive process to employ. Titanium has therefore been used,
up until now, almost exclusively and preferably in power plant
technology and in the chemical industry.
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Summary of the Invention
It is accordingly an object of the present invention to
provide an arrangement for nondetachably connecting together
thin-walled pipes or conduits of titanium, or of a titanium
alloy, in a simple, dependable and inexpensively-executable
manner.
This and other objects of the invention are achieved
by providing, for juxtaposition joinably between adjacently
disposed sections of conduit, a connector useful for attaining a
nondetachable press fit connection between the conduit sections,
thereby obviating the need to perform inert gas welding or any
other labor intensive or expensive securement techniques.
This manner of nondetachable connection, in accordance
with the invention, advantageously enables the practical and
economical use of titanium or of a titanium alloy in broad fields
o~ lnstallation techniques having particular requirements for
corrosion resistance. Moreover, these materials can readily be
handled by specialized installation companies in accordance with
the method and arrangement for connection herein disclosed. A
further advantage of this method and arrangement of nondetachable
~onnection resides in the fact that, since the connection of
conduit sections is achieved through cold pressing of the
sections -- in contradistinction to welding -- there is virtually
no danger of fire, and checking of the resulting connection can
be dispensed with since the use of an automatically-operating
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pressing tool for effecting the nondetachable securement of the
press fit connPctor to the adjacently disposed conduit sections
assures a tight connection and liquid tight seal in all
instances.
The present invention also contemplates the
accommodation of even higher forces which act in the axial
direction of the liquid-conveying conduits. For this purpose,
the connector and conduits are presse.d together not only in a
primary fit region which contains a sealing ring but, in
addition, are tightly interengaged in other areas so as to
improve mechanical clamping between the press fit connector and
the adjacently disposed conduit or pipe sections.
Other objects and features of the present invention
will be become apparent from the following detailed description
considered in conjunction with the accompany.ing drawings. It is
to be understood, however, that the drawings are designed solely
for purposes o~ illustration and not as a definition of the
limits of the invention, for which reference should be made to
the appended claims.
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Brief Description of the Drawinqs
In the drawings, wherein similar reference characters
denote similar elements throughout the several views:
Fig. 1 is a partial longitudinal section through a
nondetachable connection between a press fit connector and a
conduit section in accordance with the present invention, with
the pres ing tool still applied; and
Fig. 2 is a cross-sectional view taken along the lines
A-A in Fig. 1.
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Detailed Description of the Preferred Embodiment
A nondetachable connection between a section of pipe
or conduit 1 and a press fit coupling member or connector 3, in
accordance with the present invention, is illustrated in Fig. 1.
Each of the pipe 1 and the press fit connec:tor 3 is formed of
titanium or of a titanium alloy, although t:he fabrication of the
pipes and connectors from other suitable materials at the option
of the user is also within the scope and contemplation of the
invention. As shown in Fig. 1, the end of the pipe 1 is slidably
inserted into the press fit connector 3 so that the pipe end is
received in coaxially nested relation within the connector 3.
More particularly, the pipe 1 is slidably inserted into the
interior of the press fit connector 3 until the pipe end abuts,
and its further inward motion is halted by, the stop 2 which is
defined by a radially or diametrically-reduced portion of the
connector's interior periphery.
In the most preferred form of the invention wherein the
conduits are intended for use in a plumbing application or the
llke, the pipe 1 is seamless or welded and is formed with a
relatively thin wall. The wall thickness of the pipe may, for
example, be~in the range of approximately 0.5 to 3.0 mm and,
correspondingIy, the pipe's outside diameter may be in the range
of 10 to 100 mm. Other applications and wall thicknesses and
diameters are also within the intended scope of the invantion.
754
The press fit connector 3 is formed of a continuous
wall or sidewall which peripherally bounds an opening and thereb~
defines an elongated, substantially tubular member. The
connector 3 further includes a bead-shaped end 4, within the
hollow o~ which a round and deformable sealing ring 5 of, for
example, butyl rubber is provided. It is generally intended, for
most applications, that the press fit connector 3 will include
such a bead-shaped end 4 and sealing ring 5 at each of its
longitudinally opposed ends. After the end of a pipe 1 has been
slidably inserted into the press fit connector 3 and advanced up
to the stop ~, the opposed jaws 6, 7 of a pressing tool ~not
shown) are moved into surrounding relation with the bead-shaped
end 4 of the connector 3 and are then closed by hydraulically or
electromagnetically-applied, for example, pressure. In this
manner the press fit connector -- and, in particular, the bead-
shapèd end 4 -- is appropriately deformed or otherwise clamped
against the outer periphery of the pipe 1 to nondetachably
connect the press fit connector 3 and pipe 1 in a form-locked and
force-locked manner.
In order to further improve the mechanical clamping of
the press fit connector 3 about the pipe 1, the interior diameter
8 of the pipe 1 is preferably reduced in the vicinity of the
press-fit engagement. This reduction may be effected through the
application of a radially inwardly directed pressure applied to
the connector 3 by the jaws 6, 7 not only in the area of its
bead-shaped end 4 but, in addition, at one or more locations
54
longitudinally inward from the bead-shaped end. This arrangement
r~sults in a notable increase in the effective resistance to
longitudinal forces which occur and which tend to urge the pipe 1
out of its coaxially-nested engagement with the press fit
connector 3.
It is also contemplated that the as-fabricated inner
diameter of the press fit connector 3 may, optionally, decrease
between the bead-shaped end 4 and the location of the stop 2.
Such a decrease -- which is preferably gradual or continuous --
in the connector's inner diameter will be effective to further
increase the force-locked retention or securement of the pipe 1
within and to the press fit connector 3.
As pressure is applied by th~ pressing tool jaws 6, 7,
the diameter of the bead-shaped end 4 of the press fit connector
3 is reduced and the hollow space within the bead is also
reduced. This results in enhanced sealing action between the
press fit connector 3 and the pipe 1 as the enclosed, initially
round or arcuate sealing ring 5 is elastically deformed about the
exterior periphery of the pipe 1, thereby providing an enhanced
liquid-tight seal between the connector and pipe.
In the cross-sectional view of Fig. 2, the opposed jaws
6, 7 of the pressing tool are fully advanced into clamping
relation about the press fit connector and the form-locked and
force-locked clamping of the connector 3 to the pipe 1 can
readily be observed. In the illustrated embodiment of the
invention, the shape of the jaws 6, 7 results in a substantially
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hexagonal cross-sectional configuration of the nondetachable
connection or joinder between the press fit connector 3 and the
pipe 1. The inclusion of small hollow spaces 9, 9' which are
defined between the opposed jaws 6, 7 in the plane of separation
between the ~aws and immediately adjacent the outer periphery of
the press fit connector 3 permits an outward flow of excess
material as the jaws are clamped together.
Numerous modifications to the embodiment of the
invention herein described and illustrated in the drawings are
within the intended scope of the invention. For example, in lieu
of a separate press fit connector or coupliny member disposed
between two adjacently situated pipe or conduit sections, the
appropriate structural features of the press fit connector may be
incorporated directly on one section of the pipe at or proximate
its end, thereby enabling two sections of pipe to be
nondetachably coupled one to the other without the juxtaposition
of a separate connector 3. A press fit connector carrying the
structural pipe-engaging or coupling features at or proximate
only one of its ends -- as, for example, at the end of a liquid
transport path where it may only be necessary to provide a
suitable press fit connection to one section of pipe or conduit
-- is also within the contemplation of the invention.
Thus, while there have been shown and described and
pointed out fundamental novel features of the invention as
applied to a preferred embodiment thereof, it will be understood
that various omissions and substitutions and changes in the form
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and details of the device illustrated and in its operation may be
made by those skilled in the art without departing from the
spirit of the invention. It is the intention, therefore, to be
limited only as indicated by the scope of the claims appended
hereto.
