HK40098355A - Seal with lip projections - Google Patents

Description

Seals with raised lips

This application is a divisional application of PCT patent application "Seal with Lip Protrusion" (National Application No.: 201680072153.4, Applicant: Victorrick Corporation), which entered the Chinese national phase on June 8, 2018.

Cross-references to related applications

This is an international application of U.S. Utility Patent Application No. 14/963,361, filed on December 9, 2015, the entire contents of which are incorporated herein by reference.

Technical Field

This invention relates to seals for mechanical couplings and fittings used to connect pipe components.

Background Technology

Mechanical couplings and fittings used to connect pipe components (such as elbows and tees) employ flexible, resilient seals to form a fluid-sealed joint capable of withstanding the operating pressures of the specific application. In operation, the seal is positioned between segments or housing portions bolted together to form the coupling or fitting. The seal has a circumferential sealing surface that engages the outer surface of the pipe component when the pipe component is inserted into or otherwise engaged with the coupling or fitting. When the bolts are properly tightened, the seal compresses between the coupling segment or housing portion and the pipe component, engaging and mechanically restraining the pipe component, thus forming a fluid-sealed joint capable of withstanding the required design operating pressures.

However, in piping networks with dozens or hundreds of mechanical connections and fittings, it is possible that one or more connections or fittings may be improperly installed. The most common problem is that bolts are not tightened or not tightened sufficiently. This connection or fitting may not be fluid-tight at the operating pressure, but because the seal has a sealing surface that engages the pipe element before the bolt is tightened, this improperly installed connection or fitting may tend to maintain a fluid seal at the relatively low test pressure used to check the integrity of the piping network, and thus may give an incorrect indication of proper installation. Since improperly installed connections do not leak at the test pressure, they may not be discovered until the full operating pressure is applied to the network. It is desirable to avoid this situation, and therefore advantageous to have seals that intentionally leak when a connection or fitting to which the seal is part is improperly installed.

Summary of the Invention

This invention relates to a seal. In one exemplary embodiment, the seal includes a ring having an outer peripheral wall extending circumferentially around it. A first leaf is attached to the outer peripheral wall. The first leaf extends circumferentially around the ring. A first sealing surface is positioned on the first leaf. The first sealing surface extends circumferentially around the ring. At least a first protrusion extends from the first sealing surface. The first protrusion defines a closable leakage path across the first sealing surface.

For example, the first leaf may include a free edge, and a first protrusion is positioned adjacent to the free edge. In another example, the first leaf includes a free edge, and a first protrusion is positioned distal to the free edge. Furthermore, for example, the seal includes at least a second protrusion extending from a first sealing surface, the second protrusion defining a closable leakage path across the first sealing surface.

In one exemplary embodiment, the first leaf includes a free edge, and the first and second protrusions are positioned proximal to the free edge. For example, the first and second protrusions may be positioned near each other. In another example, the first and second protrusions are positioned angularly spaced apart from each other around the ring. In a specific example, the first and second protrusions are positioned 180° apart from each other. In another embodiment, the first leaf includes a free edge, and the first and second protrusions are positioned distal to the free edge. In another embodiment, the first and second protrusions are positioned adjacent to each other. In another example, the first and second protrusions are positioned angularly spaced apart from each other around the ring. In a specific example, the first and second protrusions are positioned 180° apart from each other.

Furthermore, for example, the first leaf may include a free edge, and the first protrusion is positioned adjacent to the free edge, while the second protrusion is positioned distal to the free edge. In another embodiment, the first and second protrusions are positioned adjacent to each other. Furthermore, for example, the first and second protrusions are positioned angularly spaced apart from each other around the ring. In a particular example, the first and second protrusions are positioned 180° apart. In a particular exemplary embodiment, the first protrusion has a projecting, curved shape. In a particular example, the first protrusion is hemispherical.

As a further example, the seal includes a third protrusion and a fourth protrusion extending from the first sealing surface. The third and fourth protrusions define a closable leakage path across the first sealing surface. In one exemplary embodiment, the third and fourth protrusions are positioned proximal to each other at a free edge. In a specific example, the third and fourth protrusions are positioned distal to each other at a free edge. In another example, the third and fourth protrusions are positioned angularly spaced apart from the first and second protrusions around a ring.

Exemplary sealing embodiments may include a fifth and a sixth protrusion extending from a first sealing surface. The fifth and sixth protrusions define corresponding closable leakage paths across the first sealing surface. In one specific example, the fifth and sixth protrusions are positioned proximal to each other at a free edge. In another example, the fifth and sixth protrusions are positioned distal to each other at a free edge. Furthermore, for example, the fifth and sixth protrusions are positioned angularly spaced around a ring with respect to a third and fourth protrusion, and the third and fourth protrusions are positioned angularly spaced around a ring with respect to a first and second protrusion. In a particular exemplary embodiment, the fifth and sixth protrusions are positioned 120° apart from the third and fourth protrusions, and the third and fourth protrusions are positioned 120° apart from the first and second protrusions.

For example, the seal may also include a second blade attached to an outer peripheral wall opposite the first blade. A second sealing surface is positioned on the second blade. The second sealing surface extends circumferentially around the ring. In another example, at least a second protrusion extends from the second sealing surface, defining a closable leakage path across the second sealing surface.

Another exemplary seal includes a first ring having a first outer peripheral wall extending circumferentially around it. A first leaf is attached to the first outer peripheral wall. The first leaf extends circumferentially around the first ring. A first sealing surface is positioned on the first leaf. The first sealing surface extends circumferentially around the first ring. At least a first protrusion extends from the first sealing surface. The first protrusion defines a closable leakage path across the first sealing surface. A second ring has a second outer peripheral wall extending circumferentially around the second ring. A second leaf is attached to the second outer peripheral wall. The second leaf extends circumferentially around the second ring. A second sealing surface is positioned on the second leaf. The second sealing surface extends circumferentially around the second ring. A tube connects the first ring and the second ring to each other.

For example, the first leaf includes a free edge. A first protrusion is positioned proximal to the free edge. In another example, the first leaf includes a free edge, and the first protrusion is positioned distal to the free edge. In yet another example, at least a second protrusion extends from the first sealing surface. The second protrusion defines a closable leakage path across the first sealing surface. In one exemplary embodiment, the first leaf includes a free edge, and the first and second protrusions are positioned proximal to the free edge. For example, the first and second protrusions are positioned near each other. In another example, the first and second protrusions are positioned angularly spaced apart from each other around a ring. In a particular exemplary embodiment, the first and second protrusions are positioned 180° apart from each other.

In one exemplary embodiment, the first leaf includes a free edge, and the first and second protrusions are positioned distal to the free edge. In another embodiment, the first and second protrusions are positioned adjacent to each other. Furthermore, for example, the first and second protrusions are positioned angularly spaced apart from each other around the ring. In a particular instance, the first and second protrusions are positioned 180° apart from each other.

In one exemplary embodiment, the first leaf includes a free edge, and a first protrusion is positioned adjacent to the free edge, while a second protrusion is positioned distal to the free edge. For example, the first and second protrusions are positioned near each other. In another instance, the first and second protrusions are positioned at an angle around the ring and spaced apart from each other. In a particular instance, the first and second protrusions are positioned 180° apart from each other.

For example, the first protrusion has a convex, curved shape. In a specific instance, the first protrusion is hemispherical.

An exemplary embodiment may further include a third and a fourth protrusion extending from the first sealing surface. The third and fourth protrusions define a closable leakage path across the first sealing surface. In one exemplary embodiment, the third and fourth protrusions are positioned proximal to each other at the free edge. In another example, the third and fourth protrusions are positioned distal to each other at the free edge. Furthermore, for example, the third and fourth protrusions are positioned angularly spaced around the ring with respect to the first and second protrusions. In a particular exemplary embodiment, the third and fourth protrusions are positioned 180° apart from the first and second protrusions. In another exemplary embodiment, the seal further includes at least a second protrusion extending from the second sealing surface. For example, the first and second rings are oriented at an angle relative to each other. In a specific example, the first and second rings have an orientation angle of 90°.

The invention also includes a fitting for connecting at least two tubular elements together. In one exemplary embodiment, the fitting includes a first housing and a second housing attached to each other and defining at least a first receiving portion and a second receiving portion for receiving the tubular elements. The housing portions also define a fluid passage extending between the first receiving portion and the second receiving portion. A seal is positioned between the first housing portion and the second housing portion. In an exemplary embodiment, the seal includes a first ring having a first outer peripheral wall extending circumferentially around it. The first ring is received within the first receiving portion. A first leaf is attached to the first outer peripheral wall. The first leaf extends circumferentially around the first ring. A first sealing surface is positioned on the first leaf. The first sealing surface extends circumferentially around the first ring. At least a first protrusion extends from the first sealing surface. The first protrusion defines a closable leakage passage across the first sealing surface. A second ring having a second outer peripheral wall extends circumferentially around the second ring. The second ring is received within the second receiving portion. A second leaf is attached to the second outer peripheral wall. The second leaf extends circumferentially around the second ring. A second sealing surface is positioned on the second leaf. The second sealing surface extends circumferentially around the second ring. The tube connects the first and second rings to each other and extends along the fluid passage. Multiple adjustable connecting parts attach the first and second housing portions to each other. The housing portions are supported in a spaced-apart relationship sufficient to allow insertion of the tube element into the receiving portion when the housing portions are attached to each other. A first sealing surface and a second sealing surface respectively contact the tube element. A first protrusion engages one of the tube elements and holds a portion of the first sealing surface spaced apart from it. The connecting parts are adjustablely tightened to pull the housing portions toward each other and compress a portion of the first sealing surface to seal against a tube element, thereby closing the leakage passage.

In one particular exemplary embodiment, the housing portions are supported in a pre-assembled state in a spaced-apart relationship sufficient to allow tubular elements to be inserted into the receiving portion.

The invention also includes a connector for connecting tubular elements end-to-end. In one exemplary embodiment, the connector includes a plurality of segments attached end-to-end to each other and surrounding a central space. Each segment has a channel extending circumferentially around and facing the central space. A connecting member is positioned at opposite ends of each segment. The connecting member is adjustablely tightened to pull the segments toward each other. A seal is positioned between the segments. For example, the seal includes a ring having an outer peripheral wall extending circumferentially around it. The ring is received within the channel. A first leaf is attached to the outer peripheral wall. The first leaf extends circumferentially around the ring. A first sealing surface is positioned on the first leaf. The first sealing surface extends circumferentially around the ring. At least a first protrusion extends from the first sealing surface. A second leaf is attached to the outer peripheral wall opposite the first leaf. The second leaf extends circumferentially around the ring. A second sealing surface is positioned on the second leaf. The second sealing surface extends circumferentially around the ring. The segments are supported in a spaced-apart relationship sufficient to allow insertion of the tubular element into the central space when the segments are attached to each other. A first sealing surface and a second sealing surface respectively contact a tubular element. A first protrusion engages a tubular element and maintains a portion of the first sealing surface spaced apart from it. Tightening the connecting components pulls the segments toward each other, thereby compressing a portion of the first sealing surface to form a sealing engagement with a tubular element, thus closing the leakage path. In an exemplary embodiment, the segments, in a pre-assembled state, are supported on the seal in a spaced-apart relationship sufficient to allow the tubular element to be inserted into the central space.

Attached Figure Description

Figure 1 is an axial view of an exemplary embodiment of the seal according to the present invention;

Figures 1A and 1B are partial views of additional exemplary embodiments of the seal according to the present invention;

Figure 2 is a cross-sectional view taken at line 2-2 in Figure 1;

Figure 3 is an axial view of an exemplary coupling using the exemplary seal shown in Figure 1;

Figure 4 is a cross-sectional view taken at line 4-4 in Figure 3;

Figure 5 is a longitudinal cross-sectional view showing the formation of a pipe fitting using the exemplary seal shown in Figure 1;

Figure 5A shows a portion of Figure 5 at an enlarged scale;

Figures 5B and 5C show enlarged axial views of partial cross sections taken at lines 5B and 5C in Figure 5, respectively.

Figure 6 is a longitudinal cross-sectional view showing the formation of a pipe fitting using the exemplary seal shown in Figure 1;

Figure 6A shows a portion of Figure 6 at an enlarged scale;

Figures 6B and 6C show enlarged axial views of partial cross sections taken at lines 6B and 6C in Figure 6, respectively.

Figure 7 is a longitudinal cross-sectional view of another exemplary embodiment of the seal according to the present invention;

Figure 8 is an isometric view of the seal shown in Figure 7;

Figure 9 is an exploded isometric view of another embodiment of an exemplary seal according to the present invention;

Figure 10 is an isometric view of an exemplary fitting using the exemplary seal shown in Figure 7;

Figure 11 is a longitudinal section view of the fitting taken at line 11-11 in Figure 10;

Figure 12 is an isometric view of an exemplary fitting using the exemplary seal shown in Figure 7; and

Figure 13 is a longitudinal section view of the fitting taken at line 13-13 in Figure 12.

Detailed Implementation

Figures 1 and 2 illustrate an exemplary seal 10 according to the invention. The seal 10 is formed of a flexible, elastic material such as EPDM, nitrile rubber, and other elastomers, and includes a ring 12 having an outer peripheral wall 14 extending circumferentially around the ring. A first leaf 16 is attached to the outer peripheral wall 14, also extending circumferentially around the ring. A first sealing surface 18 is positioned on the first leaf. The sealing surface 18 extends circumferentially around the ring 12 and engages a tubular element to achieve a seal for a fluid seal as described below (see also Figures 5 and 6). At least one protrusion 20 extends from the sealing surface 18. When the sealing surface 18 engages the tubular element, the protrusion defines a closable leakage path 22 across the sealing surface by maintaining a spaced-apart relationship between a portion of the sealing surface and the tubular element.

In the exemplary seal 10, there are six protrusions 20 arranged in three pairs of 24, 26, and 28, with each pair of protrusions 20 positioned near each other. Each protrusion forms a potential leakage path 22 between and near the protrusions 20. The pairs of protrusions 24, 26, and 28 are arranged at an angle around the ring and spaced apart from each other on the sealing surface 18. In this specific example, the pairs are positioned 120° apart from each other (see Figure 1). Other angled configurations are, of course, also possible.

Leaf 16 has a free edge 30, and protrusions 20 are shown in Figures 1 and 2 positioned on the sealing surface 18 proximal to the free edge 30. As shown in Figure 1A, other configurations are also anticipated to be effective in creating a closable leakage path 22, wherein adjacent protrusions 20 are positioned at an angle around the ring 12 about spaced apart from each other on the sealing surface 18 distal to the free edge 30. Figure 1B shows another configuration in which a pair of adjacent protrusions 20 are positioned on the sealing surface 18, one protruding proximal to the free edge 30 and the other distal to it. In this example, the protrusions 20 are positioned at an angle around the ring 12 about spaced apart from each other.

In exemplary sealing embodiment 10, the protrusion has a convex, curved shape. As shown in Figures 1 and 2, the shape is in the form of a hemispherical shape 32. Other convex shapes such as ellipsoids, ellipses, etc., are also feasible. Non-convex shapes such as cones, cubes, parallelepipeds, and pyramids are also expected to be effective as protrusions 20.

The exemplary seal embodiment 10 of Figures 1 and 2 is used in conjunction with a mechanical coupling 34, an example of which is shown in Figures 3 and 4. The seal 10 for use with the coupling 34 has a second leaf 36 attached to an outer peripheral wall 14 opposite to the first leaf 16, the second leaf extending circumferentially around a ring 12. A second sealing surface 38 is positioned on the second leaf 36, also extending circumferentially around the ring 12. The second leaf 36 has a free edge 40. As shown in Figure 2, in the various configurations described above, a protrusion 20 may also be positioned on the second leaf 36. In this exemplary embodiment, only a single protrusion 20 is present on the second leaf 36.

As shown in Figures 3 and 4, the connector 34 includes multiple segments, in this example two segments 42 and 44, connected end-to-end to each other, thus surrounding the central space 46. As shown in Figure 4, each segment 42 and 44 has a channel 48 extending circumferentially around and facing the central space 46. As shown in Figure 3, a connecting member 50 is positioned at the opposite ends of each segment 42 and 44. The connecting member 50 is adjustablely tightened to pull segments 42 and 44 toward each other. In this example, the connecting member 50 includes lugs 52 projecting outward from the ends of segments 42 and 44. Lugs 52 receive fasteners 54, which provide mechanical adjustment to pull the segments toward each other when tightened.

As shown in FIG. 4, the seal 10 is received within the channels 48 of the respective segments 42 and 44 and positioned between the segments. In a particular exemplary embodiment, the seal 10 is sized to support the spaced-apart segments sufficiently to allow the tubular element to be inserted into the connector in the pre-assembled state shown in FIG. 3. In the pre-assembled state, segments 42 and 44 are supported in a spaced-apart relationship and held against the seal 10 by fasteners 54.

Figures 5 and 6 illustrate how to form a pipe fitting using an exemplary seal 10 according to the invention. As shown in Figure 5, pipe elements 56 and 58 are inserted into the central space 46 defined by segments 42 and 44 of the coupling 34 while in their pre-assembled state. Note that the pipe elements engage and deflect the sealing surfaces 18 and 38 of the seal 10. When there are no one or more protrusions 20 on at least one of the sealing surfaces 18 or 38, it is possible for a low-pressure seal to form between the seal 10 and the pipe element, regardless of whether the fasteners 54 are tightened or not sufficiently tightened to form a suitable sealing joint. As a result, during low-pressure testing of the piping network, the network may maintain pressure and exhibit a fluid seal, thus giving an incorrect indication that all couplings have been correctly installed. However, when (much) greater operating pressure is applied to the network, those joints that are not tightened or not sufficiently tightened may leak.

In another embodiment, the connector is not pre-assembled, allowing the seal to be removed from between segments by inserting a receiving tube element, but which must first be disassembled. During removal, the seal is first lubricated and then extends to receive the first of the tube elements, with the seal fully positioned on one tube element. The second tube element is then positioned end-to-end with respect to the first tube element, and the seal moves so that the corresponding sealing surfaces engage the respective tube elements. With the seal in place on both tube elements, one segment is placed at a time, spanning the ends of the tube elements, and a ring seal is held between them.

As shown in Figures 5A and 5B (for both pre-assembled and non-pre-assembled couplings), if one or more protrusions 20 are present on one or more sealing surfaces 18 and 38 (shown as 38), they prevent premature sealing by providing a leakage path 22 between the sealing surfaces 18 and 38 and the pipe elements 56 and 58 while the coupling 34 is still in a pre-assembled state (or before the fasteners are tightened for non-pre-assembled couplings). The leakage path is formed because the protrusions 20 maintain the position of one or both of the sealing surfaces 18 and 38 in a spaced-apart relationship with the pipe elements. The leakage path 22 provided by the protrusions 20 ensures that a low-pressure test will reliably demonstrate that all couplings are correctly installed. As shown in Figures 6, 6A, and 6B, the leakage path 22 closes and forms an effective seal when the fasteners 54 (also see Figure 3) are fully tightened, pulling the segments 42 and 44 toward each other, thereby compressing and deforming the seal 10 and forcing the engagement between the segments and the pipe elements to form a fluid-sealed mechanical joint. The comparison in Figures 5A and 6A shows in detail that the leakage path is achieved by deformation of the blade 36 so that the outer 38a of the sealing surface 38 contacts the tube element 58. Figures 5C and 6C show similar behavior of the blade 16 with two protrusions 20, wherein the outer 18a of the sealing surface 18 achieves a seal relative to the tube element 56. For example, adequacy of the tightening can be demonstrated by the "pad-to-pad" engagement between the opposing lugs 52 on segments 42 and 44 (see Figure 3), or by tightening the fasteners to a mechanical joint that achieves a fluid seal by means of a specific torque known through design and experimentation. Engagement between the coupling 34 and the tube element can be achieved by engaging the inwardly projecting keys 60 on the respective segments of the circumferential groove 62 in the tube element as shown in Figure 6. Although a grooved tube element is shown, this is merely illustrative, and it should be understood that the seal according to the invention is also effective when used in combination with flat-end and shoulder-end tube elements.

Figures 7 and 8 illustrate another exemplary seal 64 according to the invention. Seal 64 is formed of a flexible, elastic material, such as EPDM, nitrile rubber, and other elastomers, and is used in conjunction with fittings, such as the elbow fittings shown in Figures 10-13. Seal 64 includes a first ring 66 having an outer peripheral wall 68 extending circumferentially around the first ring. A first leaf 70 is attached to the outer peripheral wall 68, also extending circumferentially around the ring. A first sealing surface 72 is positioned on the first leaf. The sealing surface 72 extends circumferentially around the first ring 66 and engages a tubular element to achieve a seal for a fluid seal as described below. At least one protrusion 74 extends from the first sealing surface 72. When the first sealing surface 72 engages a tubular element, the protrusion defines a closable leakage path 76 across the sealing surface. Seal 64 also includes a second ring 78 having an outer peripheral wall 80 extending circumferentially around the second ring. A second leaf 82 is attached to the outer peripheral wall 80, also extending circumferentially around the ring. A second sealing surface 84 is positioned on the second leaf. A sealing surface 84 extends circumferentially around a second ring 78 and engages a tubular element to achieve a seal for the fluid seal described below. At least one protrusion 74 extends from the second sealing surface 84. When the second sealing surface 84 engages the tubular element, the protrusion defines a closable leakage path 76 across the sealing surface. A tube 86 connects the first ring and the second ring to each other. The tube 86 may be integrally formed with the first ring 66 and the second ring 78, or it may comprise a separate component as shown in FIG. 9.

In the exemplary seal 64 shown in Figure 8, there are four protrusions arranged in two pairs 88 and 90, with each pair of protrusions 74 arranged adjacent to each other. Each protrusion forms a potential leakage path 76 between and near the protrusions 74. The protrusion pairs 88 and 90 are arranged at an angle around the ring and spaced apart from each other on one or both of the sealing surfaces 72 and 84 (also see Figure 7). In this specific example, the pairs are positioned 180° apart from each other (see Figure 8). Other angled configurations are of course also possible.

As shown in Figure 7, the first leaf 70 and the second leaf 82 have corresponding free edges 92 and 94, respectively. The protrusion 74 shown in Figure 7 is positioned on the sealing surfaces 72 and 84 proximal to the free edges 92 and 94. As shown in Figure 9, other configurations are also anticipated to be effective in creating a closable leakage path 76, wherein adjacent protrusions 74 are positioned at an angle around the ring 66 about spaced apart from each other on the sealing surface 72 distal to the free edge 92. Figure 9 shows another configuration in which a pair of adjacent protrusions 74 are positioned on the sealing surface 72, one protruding proximal to the free edge 92 and the other distal to it. In these examples, the protrusions 74 are positioned at an angle around the ring 66 about spaced apart from each other.

In exemplary sealing embodiment 64, the protrusion 74 has a protruding, curved shape. As shown in Figures 7-9, the shape is in the form of a hemispherical shape 96. Other protruding shapes such as ellipsoids, ellipses, etc., are also feasible. Non-protruding shapes such as cones, cubes, parallelepipeds, and pyramids are also expected to be effective as protrusion 74.

As shown in Figure 7, the first ring 66 and the second ring 78 are oriented at an angle relative to each other; that is, the plane 66a containing ring 66 is oriented at an angle relative to the plane 78a containing ring 78. In the exemplary embodiment shown, the orientation angle 98 is 90°, consistent with a 90° elbow fitting, but other orientation angles are of course possible.

The exemplary sealing embodiment 64 shown in Figures 7 and 9 is used in conjunction with the fitting 100 shown in Figures 10-13. Fitting 100 includes a first housing portion 102 and a second housing portion 104, which are attached to each other and thereby define first and second receiving portions 106 and 108, and a fluid passage 110 extending therebetween (Figure 11). Receiving portions 106 and 108 receive tubular elements 112 and 114. As shown in Figures 10 and 11, the sealing member 64 is positioned between the first housing portion 102 and the second housing portion 104. A ring 66 of the sealing member 64 is received within the receiving portion 106, and a ring 78 of the sealing member 64 is received within the receiving portion 108. A tube 86 extends along the fluid passage 110 defined by the housing portions 102 and 104.

As shown in Figure 10, a connecting member 116 is positioned on housing portions 102 and 104. The connecting member 116 is adjustablely tightened to pull housing portions 102 and 104 toward each other. In this example, the connecting member 116 includes a lug 118 that projects outwardly from housing portions 102 and 104. The lug 118 receives a fastener 120, which provides mechanical adjustment to pull the housing portions toward each other when tightened.

For the specific exemplary embodiment shown in Figures 10-13, the rings 66 and 78 of the seal 64 are sized to support the spaced-apart housing portions 102 and 104 in a pre-assembled state, sufficiently to allow tubular elements to be inserted into the fitting shown in Figure 10. In the pre-assembled state, the housing portions 102 and 104 are supported in a spaced-apart relationship and held against the rings 66 and 78 by fasteners 120.

Figures 10-13 illustrate how a pipe fitting can be formed using an exemplary seal 64 according to the invention. As shown in Figure 10, pipe elements 112 and 114 are inserted into receiving portions 106 and 108 defined by housing portions 102 and 104 of fitting 100 while in a pre-assembled state. As shown in Figure 11, upon insertion, pipe elements 112 and 114 engage and deflect sealing surfaces 72 and 84 of seal 100. When there are no one or more protrusions 74 on at least one of sealing surfaces 72 or 84, a low-pressure seal may form between seal 100 and pipe elements, regardless of whether fastener 120 is tightened or not sufficiently tightened to form a suitable sealing joint. As a result, during low-pressure testing of the piping network, the network may maintain pressure and exhibit a fluid seal, thus giving an incorrect indication that all fittings have been correctly installed. However, when (much larger) operating pressures are applied to the network, those joints that are not tightened or not sufficiently tightened may leak.

However, if one or more protrusions 74, as shown in the figures, are present on one or both sealing surfaces 72 and 84, they prevent premature sealing while the fitting 100 is still in a pre-assembled state by providing a leakage path 76 between the sealing surfaces 72 and 84 and the pipe elements 112 and 114. The leakage path is formed because the protrusions 74 maintain the position of one or both of the sealing surfaces 72 and 84 in a spaced-apart relationship with the pipe elements. The leakage path 76 provided by the protrusions 74 ensures that a low-pressure test will reliably demonstrate that all fittings are correctly installed. As shown in Figures 12 and 13, when the fasteners 120 are fully tightened to pull the housing portions 102 and 104 toward each other, the leakage path 76 closes and forms an effective seal, thereby compressing and deforming the seal 64 and forcing the engagement between the housing portion and the pipe element to form a fluid-sealed mechanical joint. As seen in the comparison in Figures 11 and 13, the behavior of seal 64 is similar to that of seal 10 in that, when the fastener is tightened, the blades 70 and 82 deform so that the outer surfaces 72a and 84a of the sealing surfaces 72 and 80 engage with the tube elements 112 and 114, respectively, to achieve a seal. Sufficient tightening can be demonstrated, for example, by the "pad-to-pad" engagement between opposing lugs 118 on the housing portions 102 and 104 (as shown in Figure 12), or by tightening the fastener 120 to a mechanical joint that achieves a fluid seal by a specific torque known through design and experimentation. Engagement between fitting 100 and tube elements 112 and 114 can be achieved by inwardly projecting keys 122 that surround the respective receiving portions of the circumferential grooves 124 in the tube elements as shown in Figure 13. Although grooved tube elements are shown, this is merely illustrative, and it should be understood that the seal according to the invention is also effective when used in combination with flat-end and shoulder-end tube elements.

Seals for couplings and fittings with leakage path characteristics as described in the examples herein are expected to improve the reliability of pressure testing of piping networks and thus increase the efficiency of mechanical joint installation.

Claims (19)

1. A connector for connecting pipe elements end-to-end, the connector comprising: Multiple segments are attached end-to-end to each other and surround a central space, each of the segments having a channel extending circumferentially around the central space and facing the central space. Connecting components are positioned at opposite ends of each of the segments, the connecting components being adjustable to pull the segments toward each other; A seal positioned between the segments, the seal comprising: It has a ring with an outer peripheral wall extending circumferentially around it, the ring being housed within the channel; A first leaf is attached to the outer peripheral wall, the first leaf extending circumferentially around the ring, the first leaf including a deformable free edge; A first sealing surface is positioned on the first leaf, the first sealing surface extending circumferentially around the ring; At least a first discrete protrusion extending from the first sealing surface, the first discrete protrusion defining a closable leakage path across a portion of the free edge of the first sealing surface, the first discrete protrusion being located proximal to the portion of the free edge; A second leaf, opposite to the first leaf, is attached to the outer peripheral wall and extends circumferentially around the ring; A second sealing surface is positioned on the second leaf, the second sealing surface extending circumferentially around the ring; The segments are supported in a spaced-apart relationship sufficient to allow the tubular element to be inserted into the central space when the segments are attached to each other. The first sealing surface and the second sealing surface respectively contact the tubular element. The first discrete protrusion engages one of the tubular elements and maintains a portion of the first sealing surface in a spaced-apart relationship with it. Tightening the connecting member pulls the segments toward each other, thereby compressing the portion of the first sealing surface into a sealing engagement with the one tubular element, thereby closing the leakage path. 2. The connector according to claim 1, wherein the segments are supported on the seal in a pre-assembled state in a spaced-apart relationship to allow the tubular element to be inserted into the central space. 3. The connector according to claim 1, characterized in that it further comprises at least a second discrete protrusion extending from the first sealing surface, the second discrete protrusion defining a closable leakage path across the first sealing surface. 4. The connector according to claim 3, wherein the second discrete protrusion is positioned near the free edge. 5. The connector according to claim 3, wherein the first discrete protrusion and the second discrete protrusion are positioned adjacent to each other. 6. The connector according to claim 3, wherein the first discrete protrusion and the second discrete protrusion are positioned at an angle around the ring and spaced apart from each other. 7. The connector according to claim 5, wherein the first discrete protrusion and the second discrete protrusion are positioned 180° apart from each other. 8. The connector according to claim 3, wherein the second discrete protrusion is positioned on the far side of the free edge. 9. The connector according to claim 8, wherein the first discrete protrusion and the second discrete protrusion are positioned adjacent to each other. 10. The connector according to claim 8, wherein the first discrete protrusion and the second discrete protrusion are positioned at an angle around the ring and spaced apart from each other. 11. The connector according to claim 10, wherein the first discrete protrusion and the second discrete protrusion are positioned 180° apart from each other. 12. The connector according to claim 1, wherein the first discrete protrusion has a protruding curved shape. 13. The connector according to claim 12, wherein the first discrete protrusion is hemispherical. 14. The connector of claim 5, further comprising a third discrete protrusion and a fourth discrete protrusion extending from the first sealing surface, the third discrete protrusion and the fourth discrete protrusion defining respective closable leakage paths across the first sealing surface. 15. The connector according to claim 14, wherein the third discrete protrusion and the fourth discrete protrusion are positioned adjacent to each other on the proximal side of the free edge. 16. The connector according to claim 14, wherein the third discrete protrusion and the fourth discrete protrusion are positioned adjacent to each other on the distal side of the free edge. 17. The connector according to claim 14, wherein the third discrete protrusion and the fourth discrete protrusion are positioned at an angle around the ring and spaced apart with respect to the first discrete protrusion and the second discrete protrusion. 18. The connector according to claim 17, wherein the third discrete protrusion and the fourth discrete protrusion are positioned 180° apart from the first discrete protrusion and the second discrete protrusion. 19. The coupling according to claim 1, characterized in that it further comprises at least a second discrete protrusion extending from the second sealing surface, the second discrete protrusion defining a closable leakage path across the second sealing surface.