Pipe joints or couplings – Particular interface – Annular socket
Reexamination Certificate
2002-05-24
2004-08-17
Browne, Lynne H. (Department: 3679)
Pipe joints or couplings
Particular interface
Annular socket
C285S247000, C285S334500
Reexamination Certificate
active
06776440
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and structure for preventing slipping-off of a tube in a pipe joint made of resin, and more particularly to a method and structure for preventing slipping-off of a tube in a pipe joint made of resin which is preferably used in piping for a liquid having high purity or ultrapure water to be handled in a production process in, for example, production of semiconductor devices, production of medical equipment and medicines, food processing, and chemical industry.
2. Description of the Prior Art
As a pipe joint made of resin of this kind, for example, known is a pipe joint shown in
FIG. 8
(for example, Japanese Utility Model Publication No. 7-20471). The pipe joint made of resin comprises a joint body
1
and a union nut
2
which are made of resin such as fluororesin having excellent heat resistance and chemical resistance. An inner ring
4
is pressingly inserted into one end portion
3
a
of a tube
3
which is to be inserted into joint body
1
to be connected thereto, and which is the made of resin such as fluororesin.
In the joint body
1
, a receiving port
6
is formed at least in one end of a cylindrical body portion
5
, a first primary sealing portion
7
is formed in an inner area of the receiving port
6
so that the sealing portion intersects the axis C of the joint body
1
, and a secondary sealing portion
8
is formed in an entrance area of the receiving port
6
so that the sealing portion intersect the axis C. An external thread portion
9
is formed on the outer periphery of the receiving port
6
. The inner diameter of the receiving port
6
is larger than that of the body portion
5
. In the inner area of the receiving port
6
, the first primary sealing portion
7
is formed by a tapered face which is smaller in diameter as further moving toward the outer side in the axial direction and then reaches the inner radial face of the body portion
5
. On the other hand, the secondary sealing portion
8
is formed by a tapered face which is larger in diameter as further moving from the inner area of the receiving port
6
toward the outer side in the axial direction and then reaches the end face of the receiving port
6
.
The inner ring
4
is a molded piece of resin such as fluororesin. In the inner ring, a protruding portion
10
having an outer diameter that allows the portion to be fitted into the receiving port
6
of the joint body
1
is formed in an inner end portion in the axial direction, and a press insertion portion
11
which is to be pressingly inserted into the one end portion
3
a
of the tube
3
is formed in an outer end portion in the axial direction, thereby shaping the inner ring into a sleeve-like shape as a whole. An inner end sealing portion
12
which abuts against the first primary sealing portion
7
, and which is configured as a tapered face is formed in the inner end face of the protruding portion
10
. The press insertion portion
11
consists of a bulge portion
11
a
, and a connecting portion
11
b
which connects the bulge portion
11
a
to the protruding portion
10
. The outer diameter of the connecting portion
11
b
is set to be smaller than that of the protruding portion
10
by a degree corresponding to the thickness of the tube
3
. The bulge portion
11
a
is formed into a mountain-like section shape having: a tapered outer end sealing portion
13
which is larger in diameter as further moving from the outer end in the axial direction and toward the inner side; and a tapered face
15
which is smaller in diameter as further moving from the apex of the outer end sealing portion
13
toward the connecting portion
11
b
. The outer diameter of the apex of the outer end sealing portion
13
, i.e., the maximum outer diameter of the bulge portion
11
a
is set to be larger than the outer diameter of the connecting portion
11
b
. The tapered face
15
is formed so that the inclination angel is substantially equal to that of the secondary sealing portion
8
of the joint body
1
, and, when the inner end sealing portion
12
abuts against the primary sealing portion
7
, the gap through which the secondary sealing portion
8
is opposed to the tapered face
15
corresponds to the thickness of the tube
3
. The inner diameter of the inner ring
4
is set to be equal to or substantially equal to the inner diameters of the tube
3
and the body portion
5
of the joint body
1
, so as not to impede movement (flow) of a fluid.
The inner ring
4
is pressingly inserted into the one end portion
3
a
of the tube
3
under a state where the protruding portion
10
is outwardly projected, whereby the diameter of the one end portion
3
a
of the tube
3
is increased to form a diameter-increased portion
16
, and also to form a diameter-increased root portion
17
in a place where an opposite-insertion direction side inclination
16
a
of the diameter-increased portion
16
on the side opposite to the direction of insertion into the joint body
1
, and a tube outer face
30
which is parallel to the tube axial direction meet each other.
Under the state where the one end portion
3
a
of the tube
3
is inserted into the receiving port
6
, the inner end sealing portion
12
abuts against the first primary sealing portion
7
of the joint body
1
, and the outer end sealing portion
13
abuts against the inner face of the opposite-insertion direction side inclination
16
a
serving as a second primary sealing portion of the diameter-increased portion
16
of the tube
3
. The one end portion
3
a
of the tube
3
is clamped in an inclined state between the secondary sealing portion
8
of the joint body
1
and the tapered face
15
of the inner ring
4
. Namely, an insertion direction side inclination
16
b
of the diameter-increased portion
16
of the tube
3
which is deformed along the tapered face
15
of the inner ring
4
abuts against the secondary sealing portion
8
.
In the union nut
2
, an internal thread portion
18
which is to be screwed to the external thread portion
9
of the joint body
1
is formed on the inner peripheral face, an annular flange portion
19
is inward projected from one end, and a pressing edge portion
19
a
of an acute angle or a right angle is formed on the inner end in the axial direction of the inner peripheral face of the flange portion
19
.
Under the state where the one end portion
3
a
of the tube
3
into which the inner ring
4
is pressingly inserted is inserted into the receiving port
6
of the joint body
1
, the internal thread portion
18
of the union nut
2
which is previously loosely fitted onto the outer periphery of the one end portion
3
a
is screw-fastened to the external thread portion
9
of the joint body
1
. As a result of this fastening, the pressing edge portion
19
a
of the union nut
2
abuts against the diameter-increased root portion
17
of the diameter-increased portion
16
of the tube
3
to press the inner ring
4
in the axial direction. As a result, the inner end sealing portion
12
of the inner ring
4
, and the insertion direction side inclination
16
b
of the tube
3
are pressingly contacted with the primary sealing portion
7
of the receiving port
6
of the joint body
1
and the secondary sealing portion
8
of the tube
3
, respectively, and the inner face of the opposite-insertion direction side inclination
16
a
serving as the second primary sealing portion of the tube
3
is pressingly contacted with the outer end sealing portion
13
of the inner ring
4
, whereby the sealing property (sealing force) is exerted and at the same time the tube
3
is prevented from slipping off.
In the pipe joint made of resin in which the fastening of the union nut
2
causes the pressing edge portion
19
a
to abut against the diameter-increased root portion
17
of the diameter-increased portion
16
of the tube
3
, thereby pressing the one end portion
3
a
of the tube
3
together with the inner ring
4
against the joint body
1
, the diameter-increased root p
Browne Lynne H.
Dunwoody Aaron
Koda & Androlia
Nippon Pillar Packing Co. Ltd.
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