JP2001317684A - Anticorrosive structure for lock ring in pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a lock ring hard to be corroded even when it is brought into contact with fluid in a pipe. SOLUTION: A pipe joint 10 is so designed that a lock ring 8 seated in a housing groove 5b formed in the internal surface of a socket 5 is engaged with the external surface of a spigot 1 to prevent dislodgment of the spigot 1. The surface of the lock ring 3 seated in the housing groove 5b has the addition of a metal 8 electrically baser than the lock ring 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corrosion prevention structure for a lock ring in a pipe joint.

[0002]

2. Description of the Related Art As a pipe joint for a metal pipe such as a ductile cast iron pipe, a pipe joint as shown in FIG. 6 is known.

[0003] The pipe joint 10 has a seal rubber ring storage groove 5a and a lock ring storage groove 5b formed on the inner surface of the receiving port 5, and as shown, the seal rubber ring 2 is connected to the seal rubber ring storage groove 5a. After the lock ring 3 is attached to the lock ring storage groove 5b via the centering rubber 4, the sealing rubber ring 2 and the insertion port having the insertion projection 1a at the tip end beyond the lock ring 3 portion. 1 is inserted, when the release force acts on the joint portion 10, the insertion projection 1a and the lock ring 3 are engaged to prevent the release.

[0004]

When the pipe joint 10 is joined, the anticorrosion coating film formed on both surfaces is damaged when the insertion projection 1a crosses over the lock ring 3. As shown in FIG. 6, since the lock ring 3 comes into contact with the fluid in the pipe, there is a problem that the lock ring may be corroded.

An object of the present invention is to solve the above problems and to effectively prevent the lock ring from being corroded even when the lock ring comes into contact with the fluid in the pipe.

[0006]

According to a first aspect of the present invention, there is provided a corrosion-resistant structure for a lock ring in a pipe joint, wherein the lock ring housed in a storage groove formed in an inner surface of a receiving port is connected to an outer surface of an insertion opening. In the pipe joint which prevents the opening from coming off by fitting, a metal which is more electrically lower than the lock ring is added to the surface of the lock ring stored in the storage groove.

Therefore, according to the present invention, even if flowing water in the pipe comes into contact with the lock ring, the electrically base metal added to the surface of the lock ring is corroded first, thereby preventing the lock ring from being corroded. .

Here, the term "electrically low" refers to a metal having a high ionization tendency with respect to the lock ring. For example, zinc or the like corresponds to a steel lock ring.

[0009]

Next, an embodiment of the present invention will be described. FIG. 1 is a cross-sectional view showing a cut-out upper half of a pipe joint according to the present invention, and FIG. In FIG. 1, FIG.
Since the members denoted by the same reference numerals indicate the same or corresponding members, detailed description will be omitted by attaching the same reference numerals.

In FIG. 1, a lock ring 3 housed in a lock ring housing groove 5b on the inner surface of a receiving port 5 is made of steel or cast iron. Metal 8, for example zinc,
It is added by means such as zinc spraying.

The surface to which the metal 8 is added is a surface of the lock ring 3 which does not impair the function of the lock ring as shown in FIG.
a or inclined surface 3b, and grooves 3c, 3c
c is formed, and a metal 8 such as zinc is filled in the groove 3c by thermal spraying or the like.

The groove 3c for filling the metal 8 may be provided not only in the axial direction as shown in the figure, but also in the circumferential direction as shown in FIG. The metal 8 may be a metal having a higher ionization tendency than the lock ring, and may be a paint such as zinc-rich paint as long as it substantially contains these metals. In this case, the surface of the lock ring 3 that is not in contact with the insertion projection 1a may be painted without providing the groove 3c.

Further, depending on the type of the joint, for example, the sealing rubber ring 2 filled between the outer surface of the insertion port 1 and the inner surface of the receiving port 5 is tightened in the direction of the backup ring 11 by the push ring 9a and the bolt 9b, and the backup is performed. In the case of a joint in which the ring 11 and the lock ring 3 are brought into contact,
As shown in FIG. 4, the metal 8 is provided on the inner peripheral surface 3 e of the lock ring 3 so that the surface of the metal 8 is exposed and touches the flowing water in the pipe.
Alternatively, as shown in FIG. 5, when the lock ring 3 is tightly tightened, the groove 3 is formed on the outer surface 3 f of the lock ring 3.
A configuration may be adopted in which c is formed and the metal 8 is filled in the groove 3c so that the flowing water in the pipe comes into contact.

In FIG. 5, members denoted by the same reference numerals as those in FIG. 4 indicate the same or corresponding members, and the detailed description will be omitted by giving the reference numerals. Further, a protective cover (not shown) fitted along the inner surface of the lock ring to protect the lock ring 3 or the insertion projection 1a at the time of pipe connection may be used together with the lock ring 3.

In this case, when the cover is damaged, an anti-corrosion effect is exerted, and the lock ring 3 is not corroded for a long period of time. As described above, in this embodiment, a metal that is more electrically base than the metal that constitutes the lock ring is added to the surface of the lock ring 3, so that even if water in the pipe comes into contact with the metal, The lock ring is protected from corrosion for a long time because it is corroded from the metal that has been removed. Embodiment Next, an embodiment of the present invention will be described.

As shown in FIG. 2, the radial thickness H is 9 m.
m, an axial thickness M of 15 mm, and an outer diameter R of 93.5 mm. The lock ring 3 has a groove 3 h in width on the back side 3 a and a width 3 in the taper surface at equal circumferential intervals.
A groove of mm was formed, and zinc was added thereto by zinc spraying.

The lock ring 3 was used for a pipe joint having a nominal diameter of 150 mm as shown in FIG. And socket 5
After setting the sealing rubber ring 5 and the lock ring 3 therein, the insertion port 1 was inserted and connected, and a water flow test using tap water was performed.

As a result, no rust was found on the lock ring even after three years in the example. On the other hand, as a comparative example, when the same test was performed in parallel on a conventional lock ring not subjected to zinc spraying, rust was observed before three years had passed.

[0019]

As described above, according to the lock ring of the present invention, even if the lock ring comes into contact with the fluid in the pipe after connecting the insertion port to the receiving port, corrosion is effectively prevented and stable for a long period of time. The improved seismic function is maintained.

Further, the lock ring itself has a simple structure, so that the lock ring itself can be easily implemented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a joint in a corrosion-resistant structure of a lock ring in a pipe joint according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the lock ring according to the embodiment.

FIG. 3 is an enlarged sectional view of a main part of another configuration example of the lock ring according to the embodiment.

FIG. 4 is a cross-sectional view showing another configuration example of the corrosion prevention structure of the lock ring in the pipe joint according to the embodiment.

FIG. 5 is a cross-sectional view showing still another configuration example of the corrosion prevention structure of the lock ring in the pipe joint according to the embodiment.

FIG. 6 is an explanatory sectional view of a conventional pipe joint.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insert 1a Insert projection 2 Rubber ring for sealing 3 Lock ring 4 Centering rubber 5 Receptacle 5b Lock ring storage groove 8 Metal that is more base than the lock ring 10 Joint

Claims (1)

[Claims] 1. A pipe joint in which a lock ring housed in a storage groove formed on an inner surface of a receiving opening is engaged with an outer surface of the insertion opening to prevent the insertion opening from coming off. An anticorrosion structure for a lock ring in a pipe joint in which a metal that is more base than the lock ring is added to the surface of the ring.