Pipe joints or couplings – Packed – Externally with clamp
Utility Patent
1998-06-19
2001-01-02
Arola, Dave W. (Department: 3627)
Pipe joints or couplings
Packed
Externally with clamp
C285S369000, C285S910000
Utility Patent
active
06168210
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to pipe couplings and joints and, more particularly, to pipe couplings adapted to couple and seal adjacent ends of two pipe sections of the same or different diameters.
BACKGROUND OF THE INVENTION
Conventional pipe couplings for coupling and sealing adjacent ends of two pipe sections include a coupling sleeve or collar that overlies the junction of the pipes and is sealed at each end by an annular gasket and a follower flange. Each gasket is disposed about a respective end of the pipe sections and includes an inclined or bevelled front wall that extends radially outwardly and axially rearwardly from the nose or toe of the gasket toward the radially outwardly-most aspect (i.e., the top wall or outer diameter) of the gasket, and an axially outwardly directed flat back wall in the heel section of the gasket that extends down from the top wall to the radially inwardly-most aspect of the gasket (i.e., the bottom wall or inner diameter). The inclined front walls of the gaskets are angled generally complementary to clamping walls formed at opposite ends of the sleeve. As the pipe coupling is tightened to move the follower flanges axially toward each other, the flat back walls of the gaskets engage flat skirt walls of the follower flanges to drive the gaskets toward the sleeve. As a consequence, the inclined front walls of the gaskets are driven into the clamping walls of the sleeve to toe-in the nose or toe of the gaskets toward the outer walls of the pipes and form a fluid tight seal therebetween as the pipe coupling is tightened.
Typically, a substantial extent of the gasket back wall must contact the skirt wall of the follower flange to ensure that there is adequate surface area contact or gripping between the gaskets and follower flanges so as to reduce the amount of gasket material that may flow or extrude between the skirt walls and the outer walls of the pipes. Thus, the gasket back wall must be formed with a sufficient radial dimension to ensure that more than fifty-percent of the gasket back wall engages the skirt wall of the follower flange over a wide range of pipe wall outer diameters.
Pipe couplings of the type described above typically require significant torque to cause the gaskets to toe-in sufficiently to seal the adjacent ends of the pipe sections. Proper toe-in of the gasket is achieved only after the gasket nose has been driven into the clamping walls of the sleeve with sufficient force to turn the gasket nose toward and into sealing engagement with the adjacent ends of the pipe sections. Moreover, known annular gaskets used in conventional pipe couplings are typically quite limited in the range of toe-in, and so a given sized gasket can not readily accommodate a wide range of pipe end diameters. In the field, however, the outer diameters of the pipe sections which may need to be joined together can vary by as much as 1½ to 2½ inches for the same nominal diameter. With typical prior pipe couplings gaskets, there was a need to maintain an inventory of numerous sizes of gaskets and flanges for each nominal pipe size to accommodate the wide range of pipe ends encountered in the field.
One proposal to reduce inventory has been to provide a notch in the flat gasket back wall that is held in place by a lip formed on the flange skirt wall. The gasket is intended to be held against extrusion and to allow greater toe-in range by cooperation of the notch and the lip. It is believed, however, that such a proposal is not likely successful for a number of reasons. By way of example, it is thought that the gasket material below the lip would tend to extrude axially outwardly and could pull the gasket over the lip resulting in failure of the seal.
Thus, there is a need for a pipe coupling that will seal adjacent ends of two pipe sections of significantly different diameters with a common size gasket and flange. There is also a need for a pipe coupling that reduces extrusion of gasket material between the follower flanges and the outer pipe walls. There is yet also a need for a pipe coupling that does not sacrifice the sealing capability of the pipe coupling with adjacent ends of two pipe sections, yet toes-in at relatively low torque.
SUMMARY OF THE INVENTION
The present invention overcomes the foregoing and other shortcomings and drawbacks of the pipe couplings heretofore known. While the invention will be described in connection with one embodiment, it will be understood that the invention is not limited to that embodiment. On the contrary, the invention includes all alternatives, modifications and equivalents as may be included within the spirit and scope of the present invention.
In accordance with the principles of the present invention, a pipe coupling is provided with an annular gasket that includes a radially outwardly angled or inclined back wall formed on the heel portion of the gasket. The inclined back wall of the gasket initially forms a gap with the skirt wall of the follower flange before the pipe coupling bolts are tightened. As the bolts are tightened, the gasket back wall naturally tilts toward the skirt wall to close the gap formed therebetween. Tilting of the gasket back wall causes the nose of the gasket to toe-in toward the outer pipe wall to seal the ends of the pipe sections and to bring the gasket front wall under the clamping wall of the sleeve at lower torque than conventional pipe couplings.
Additionally, tilting of the back wall of the gasket presents a full-face of gasket material to the skirt wall. The inclined back wall of the gasket thus provides a surface area substantially equal to that of prior flat-back gaskets for contact with the skirt wall of the follower flange while allowing for the gasket to toe-in over a wider range than most conventional gaskets. With the inclined gasket back wall, the gasket heel is urged radially outwardly to thereby reduce the likelihood of extrusion of gasket material between the skirt wall and the outer walls of the pipe sections as the pipe coupling is compressed to form a seal. To further facilitate the tendency of the gasket to be urged radially outwardly and away from extruding, the skirt walls of the follower flanges may also be angled or inclined in a radially outwardly direction.
The inclined back wall of each gasket may be disposed at an angle of about 20° relative to a line perpendicular to an axis of the gasket. The inclined skirt wall of each follower flange may be disposed at an angle of about 10° relative to a line perpendicular to an axis of the follower flange such that the angle of the gasket back wall is approximately twice the angle of the skirt wall. Each follower flange may include an inclined corner wall at the top of the skirt wall to prevent snagging or pinching of gasket material between the sleeve and the follower flange as the pipe coupling is tightened. An annular bead may be formed on the inclined top wall of each gasket to reduce friction between the gasket and the sleeve clamping wall as they slide relative to each other as the pipe coupling is tightened and to help facilitate toe-in of the gasket underneath the sleeve clamping wall.
The pipe coupling of the present invention seals adjacent ends of two pipe sections at lower torque than conventional pipe couplings through the cooperation of the inclined gasket back wall and the skirt wall of the follower flange. The pipe coupling of the present invention also reduces extrusion of gasket material between the skirt wall of the follower flange and the outer walls of the pipe sections. Moreover, the pipe coupling of the present invention allows for one size of gasket and flange to be used to seal a wide range of pipe end sizes without sacrificing the sealing capability of the pipe coupling.
The above features and advantages of the present invention will be better understood with reference to the accompanying figures and detailed description.
REFERENCES:
patent: 660862 (1900-12-01), Lovekin
patent: 1567813 (1925-12-01), Oleson
patent: 1936552 (1933-11-01), Gos
Arola Dave W.
Detweiler Sean D.
M & FC Holding Company, Inc.
Martin Terrence (Terry)
Morris Jules Jay
LandOfFree
Pipe coupling does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pipe coupling, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pipe coupling will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2484997