Valve structure for use in a pipe coupling and a pipe coupling comprising the valve structure

A female or male coupler of a pipe coupling comprises a valve which is located in a fluid passage and is axially movable therein. The valve has a valve head which is provided with a sealing ring to be engaged with and disengaged from a valve seat formed on a wall surface defining the fluid passage of the coupler. The sealing ring is installed in an annular groove formed in the valve head. The bottom, or vicinity thereof, of the annular groove, which is isolated from the outside or the fluid passage by the sealing ring, is fluidly communicated with the exterior surface of the valve via a communication passage formed in the valve. As a result, even if a sudden large decrease in pressure is generated in the fluid passage, a pressure in the bottom, or the vicinity thereof, of the annular groove equalizes with the pressure in the fluid passage.

BACKGROUND OF THE INVENTION

The present invention relates to a pipe coupling, and in particular to a valve provided in a pipe coupling.

In a conventional pipe coupling comprising male and female couplers for interconnection with one another, generally the male coupler and/or the female coupler is provided with a valve for closing and opening a fluid passage existing within the pipe coupling. The valve generally has a valve head provided with a sealing ring adapted to be engaged with and disengaged from a valve seat upon axial movement of the valve within the fluid passage. (Shown in JP Utility Model Publication No. S58-187687)

FIG. 5shows part of a valve head54of a conventional-type valve50provided in a coupler fluid passage52formed, in this example, in a male coupler51. The valve50comprises a valve head54having a tapered annular surface corresponding to a valve seat53formed in an interior surface of the coupler51defining the fluid passage52. The tapered annular surface of the valve head is formed to have an annular groove55in which a sealing ring56made of rubber is disposed. The valve50is axially movably mounted in the fluid passage52and urged forward by a spring (not shown) so that the sealing ring56is sealingly engaged with the valve seat and, upon imposition of a rearward force on the valve50, the valve is moved rearward and disengaged from the valve seat53. As shown in the figure, a right side wall57of the annular groove55is inclined so as to hold the sealing ring between the right side wall57and a left side wall of the same, to thereby prevent the sealing ring from moving out from the annular groove55.

When the valve50is operated to close the fluid passage52, and the closed fluid passage is filled with a high pressure fluid, there is a possibility that the high pressure fluid will permeate into the interface between the sealing ring56and the side wall of the annular groove, and down to the bottom59of the annular groove55. In such a case, if the fluid passage, into which a high pressure fluid has been filled, is subject to a sudden decrease in pressure resulting from, for example, discharge of the high pressure fluid, a large pressure difference will be generated between the outside or the fluid passage and bottom side of the annular groove. If this occurs, the sealing ring is liable to be dislodged from the annular groove55under the action of the high pressure fluid which has permeated down to the bottom of the annular groove.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide in a coupler of a pipe coupling a valve in which a sealing ring is prevented from being forced out from an annular groove or a sealing ring holding groove formed in a valve, under the action of a high pressure fluid which has accumulated in the bottom of the sealing ring holding groove, even in a case that the valve is subject to a sudden large pressure decrease generated in a fluid passage in which the valve is provided.

According to one aspect of the present invention, there is provided a valve provided in a fluid passage of a male or female coupler for a pipe coupling such that the valve is movable in an axial direction of the fluid passage, the valve comprising:an exterior surface including an annular surface corresponding to an annular valve seat formed in an interior surface of the coupler defining the fluid passage;an annular groove formed in the annular surface;an annular sealing ring disposed in the annular groove; and,a communication passage extending from a bottom portion of the annular groove, or a vicinity thereof, through the exterior surface;the valve being axially movable in the fluid passage between a closing position wherein the annular sealing ring is engaged with the annular valve seat to close the fluid passage and an opening position wherein the annular sealing ring is disengaged from the annular valve seat to open the fluid passage.

The communication passage may extend from a bottom portion of the annular groove, or a vicinity thereof, through the exterior surface positioned rearward of or forward of the annular groove.

Further, the communication passage may extend from the bottom portion of the annular groove, or the vicinity thereof, along a side wall surface of the annular groove to form a groove extending along the wall surface, and between the bottom portion of the annular groove, or the vicinity thereof, and the annular surface.

According to another aspect of the present invention, there is provided a male or female coupler of a pipe coupling, the coupler having the characteristic features as stated above.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1illustrates a pipe coupling1to which the present invention is applied. As shown, the pipe coupling1comprises a male coupler2and a female coupler3which have fluid passages4and5, respectively, in which valves6,6are provided.

The valve6of the male coupler2is supported for axial movement in the fluid passage4by means of a valve support7secured on the interior surface of the male coupler2or the wall of the fluid passage4and urged forward by a coil spring9positioned between a valve head10and the valve support7so that the valve head10is movable between a closing position as shown inFIG. 1in which the valve head10is urged against a tapered annular valve seat11formed in the interior surface of the male coupler2to close the fluid passage4and an opening position wherein the valve head10is disengaged from the valve seat11to open the fluid passage4.

FIG. 2shows a part of a forward end portion2aof the male coupler2. As shown, the valve head10has a tapered annular surface corresponding to the tapered annular valve seat11and is provided with a sealing ring13in an annular groove12formed in the tapered annular surface. The sealing ring13made of rubber is clamped between an inclined right side wall14of the annular groove12and a left side wall of the same to be retained in the annular groove12.

In the right side wall14of the annular groove12, there is provided a communication passage16extending from the bottom15of the annular groove12through an exterior surface of the valve head, and in this embodiment, through a rear side surface of the valve head so that the bottom15of the annular groove12is fluidly communicated with the fluid passage4.

The valve6provided in the female coupler3is also axially movably supported in the fluid passage5by means of a valve support7secured to the wall surface of the fluid passage5. The configuration of the valve10is the same as that of the valve of the male coupler2described above and, therefore, detailed explanation thereof will be omitted.

InFIG. 1, reference numeral18denotes a locking mechanism for locking/unlocking the male coupler2with respect to the female coupler3. The locking mechanism comprises: a tubular coupler body3ahaving a plurality of radial holes19which are formed in a forward end portion thereof, and which are spaced apart from each other in a circumferential direction; locking balls21disposed in the radial holes19; and a sleeve23which is urged forward by a coil spring22, and which is movable between an unlocking position, in which the sleeve23is moved rearward against coil spring22to allow the locking balls21to move radially outwardly to permit the male coupler2to be inserted into the female coupler3, and a locking position in which the sleeve is moved forward by the coil spring22to force the locking balls21radially inwardly to engage them in the annular locking ball receiving groove20, formed in the exterior surface of the male coupler2, when the male coupler2is completely inserted into the female coupler.

In the embodiment described above, since the communication passage16fluidly communicates with the bottom15of the annular groove12formed around the valve6with the fluid passage4,5of the coupler2,3, even if a sudden large pressure decrease occurs in the fluid passage, no substantial pressure difference will occur between the outside or the fluid passage and the bottom side of the annular groove12, thereby avoiding the problem of the conventional art wherein the sealing ring is dislodged from the annular groove12of the valve.

FIG. 3illustrates a second embodiment of the present invention.

The male coupler2is substantially the same as that of the first embodiment described above except for the communication passage31extending from the bottom15of the annular groove12through a front surface of the valve head.

In this embodiment, if the male coupler2, wherein the fluid passage is closed and filled with a high pressure gas, is connected to a female coupler to thereby fluidly connect the fluid passages of the male and female couplers, a pressure acting around the valve30will suddenly decreases. However, since the bottom15of the annular groove12is communicated with the fluid passages through the communication passage31, no substantial pressure difference will occur between the outside or the fluid passage and the bottom side of the annular groove12. As has been stated in connection with the conventional art described above, it is the case that when a high pressure fluid is discharged from the fluid passage of the male coupler to enable the male coupler to be easily connected to the female coupler, the sealing ring is caused to be dislodged due to a sudden large change in pressure around the valve. In contrast, in the coupler in accordance with the second embodiment, dislodgement of the sealing ring due to sudden change in pressure around the valve can be avoided.

FIG. 4illustrates a third embodiment of the present invention.

In the embodiment, a communication passage41is formed as a groove extending along the right side wall surface17of the annular groove12from the bottom15of the annular groove12through the tapered annular surface of the valve head10.

As in the first and second embodiments, due to the provision of the communication passage41, no substantial difference in pressure will occur between the outside or the fluid passage and the bottom side of the annular groove, even if there is a sudden change in pressure generated around the valve.

It will be noted that the present invention has been described in an illustrative manner, and it is to be understood that the terminology that has been used is intended for the purpose of description only, and is not to be taken in any way as being limiting.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced in a manner other than that specifically set out in the foregoing description.