Compression Ring Apparatus and Method for Sealing a Pipe Liner

A sealing compression ring apparatus couplable to a liner and a pipe component has an annular body and a bore, with a first side including a raised outer edge portion, a recessed annular portion between the raised outer edge portion and the bore, and an o-ring gland encircling the bore on the recessed annular portion. A pipe assembly has a base pipe including a flange, a liner extending axially within the base pipe and extending radially out and over a portion of the flange to define a liner flange, an opposite flange surface, and a sealing compression ring apparatus compressed between the flange and the opposite flange surface, and an o-ring positioned in the o-ring gland of the ring.

TECHNICAL FIELD

The present invention relates to ring seals in general, and compression ring seals for pipes in particular.

BACKGROUND

Traditionally polymeric liners, such as those lining pipes, have relied on compression of a flange end face of the liner with an opposite face surface, such as another, mating liner flange end face, a standard pipe flange or an end cap, in order to create a sealing interface. A pipe flange, as will be appreciated, is an annular plate-like extension from the end of the pipe. The compression force is provided by compression fasteners acting through the pipe flange and the structure to which it is attached. Such compression fasteners may be, for example, bolts acting through bolt holes in the pipe flange. The pipe flange applies pressure against the liner flange so that its end face is compressed against the opposing face surface. A liner flange has a material strength that is weaker than steel so a steel ring is needed to limit the amount of compression such that the liner flange is not extruded out from compressive forces. This method works until creep reduces the interface pressure below the sealing requirement. Elastomers are more creep resistant, so using an o-ring at the liner flange end face has been desired to eliminate this issue. Unfortunately there are some challenges for example, o-ring grooves will creep away if cut into the liner plastic making replacement impossible; and o-rings located outside the liner flange interface area may prevent leaks to the exterior, but will not contain primary leaks from the liner.

SUMMARY OF INVENTION

In accordance with a broad aspect of the present invention, there is provided a sealing compression ring apparatus couplable to a liner and a pipe component, comprising: a body, being substantially annular, having a first side, a second side, and a bore extending from the first side to the second side; the first side including: a raised outer edge portion; a recessed annular portion between the raised outer edge portion and the bore; and an o-ring gland encircling the bore on the recessed annular portion.

In accordance with another broad aspect of the present invention, there is provided a pipe assembly, comprising: a base pipe including a flange having a planar face; a liner extending axially within the base pipe and extending radially out and over a portion of the flange to define a liner flange; an opposite flange surface connected by compression fasteners to the flange; and a sealing compression ring apparatus compressed between the flange and the opposite flange surface, the sealing compression ring including a body, being substantially annular, having a first side, a second side, and a bore extending from the first side to the second side; the first side including: a raised outer edge portion; a recessed annular portion between the raised outer edge portion and the bore; an o-ring gland encircling the bore on the recessed annular portion; and an o-ring positioned in the o-ring gland; the raised outer edge portion being in contact with the flange and the o-ring compressed between the liner flange and the recessed annular portion.

It is to be understood that other aspects of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein various embodiments of the invention are shown and described by way of illustration. As will be realized, the invention is capable of other and different embodiments and its several details are capable of modification in various other respects, all within the present invention. Furthermore, the various embodiments described may be combined, mutatis mutandis, with other embodiments described herein. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

DETAILED DESCRIPTION OF EMBODIMENTS

The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments contemplated by the inventor. The detailed description includes specific details for the purpose of providing a comprehensive understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.

A compression ring has been invented for use to provide primary containment at a polymeric flange end face. The ring is for sealing a plastic liner to another plastic liner or the plastic liner to a standard flange.

A sealing compression ring includes faces for sealing a plastic liner flange of a pipe to a standard gasket, another pipe flange or an opposite plastic flange, while limiting damaging compression of the aforementioned plastic flange. The ring is designed to include sealing elements (such as o-rings) of a different material from the flange to address degradation of interface pressure to the plastic flange from various causes.

With reference toFIG. 1, a lined pipe10includes a base pipe12and a liner14extending within an inner diameter12bof the base pipe. At an end of the lined pipe, the base pipe has a pipe flange12awith a planar face12a′. The liner extends out and over a portion of the pipe flange, creating a liner flange14a.The liner flange has an exposed end face14a′ that is substantially planar. The thickness of the liner flange creates an annular shoulder14a″ that creates a step between the pipe flange face12a′ and liner end face14a′.

When installed, the pipe flange12ais connected to another flange-type component16(which may be a substantially planar member) such as by bolts18. The connection of pipe flange12ato another component16by bolts creates compressive force therebetween that seals liner flange14aagainst a mating surface by compression. While prior mating surfaces may be another plastic liner flange or a pipe flange, in the present invention the lined pipe10is compression sealed against a compression ring20. The compression ring may be used, for example, to provide primary containment at the polymeric liner flange end face14a′. The ring is positioned as an insert between the lined pipe10flanges12a,14aand flange-type component16.

Ring20may be substantially annular, having a first side20aand a second side20b,an axial bore20cthat extends from the first side to the second side, and an outer cylindrical wall21. The first side20ais configured for sealing against the flanged end face of a lined pipe, while the second side20bis configured for sealing against another component16. While the first side20ais reasonably consistent, the second side can vary depending on the form of the component16against which it is sealed.

The first side20a,for example, may include a raised outer edge face22and a recessed inner face24with a step26therebetween. Recessed inner face24directly encircles bore20c.As noted, first side20ais configured for sealing against the flanged end face of a lined pipe with raised outer edge face22in contact with the pipe flange face12a′ and recessed inner face24in contact with the liner flange face14a′.

Faces22and24may each be substantially planar with face22defining a plane parallel to face24. Put another way, ring20may have an outer wall, the flatted upper surface thereof being face22and the wall is raised around a planar annular portion defining face24in which bore20cis positioned. As such, ring20may have a greater axial thickness between first side20aand second side20baround its outer edge, relative to a smaller axial thickness between first side20aand second side20bnear bore20c,and the thickness abruptly changes at the annular step26.

Step26may be concentric with bore20cbut has a diameter greater than that of bore20c. Step26may have a substantially consistent diameter from surface22to surface24. The diameter at step26may be selected such that liner flange14amay fit therein. That is, the diameter defined at step26may be equal to or greater than outer diameter of liner flange14a.In use, the outer diameter of liner flange14amay increase when under axial compression, which is commonly referred to as “creep” caused by plastic deformation due to axial compression between pipe flange12aand flange-type component16. Therefore, the amount by which inner diameter of step26is greater than the uncompressed outer diameter of liner flange14amay be selected to permit only a desired degree of increase, creep, in the outer diameter of liner flange14a.Limiting the degree of such creep prevents the liner flange14afrom degradation, thereby increasing its lifespan and reducing the incidence of failure. Permitting a limited degree of such creep of the liner flange may be useful so as to limit the degree of creep of the liner. Therefore in one embodiment, the diameter across step26, which defines the outer diameter of recessed face24, is only slightly larger than the diameter across the liner flange.

While the flanges may be standard with flat-faces, in this illustrated embodiment the pipe flange12amay be of the type having a raised face, including a step12a″. The step may be between a raised flanged face closer to the axis of the pipe, and a recessed flanged face further away from the axis. This style of flange allows machining of the sealing surface, such that the flanged face may be forged without thinning the actual flange. Step12a″ may be in substantial radial alignment with step26, such that raised outer edge face22may fit between step12a″ and bolt18.

As mentioned above, flange12ais in contact with ring20, specifically at surface22. The ring thickness at surface22, which is greater than the ring thickness at surface24, ensures that the ring transmits the majority of compressive forces from face12a′ to component16through the ring20at surface22rather than through the contact of flange14aand surface24. In particular, the ring limits compression to the plastic flange14awhile transmitting compressive forces arising from the flange bolts18through the connection. The thickness of ring at surface22relative to thickness of ring at surface24(i.e. the height of step26) may contribute to how much compression is experienced, at least initially (e.g., on a new liner that has not experienced any wear and tear) between liner flange14aand surface24. In one embodiment, it may be useful to target a degree of compression between 8% and 12%, for example, 10%, for a new liner, measured at the liner flange. After wear and tear on the liner, this degree of compression may change. To achieve a desired degree of compression, factors such as the height of step26may be selected and/or adjusted.

To mitigate leakage, one or more o-ring glands28may be provided on the first side, for example on recessed inner face24. Each o-ring gland28may have an o-ring placed therein to create a seal between ring20and liner14. The one or more o-ring glands28may be concentric with each other, step26, ring20, and/or bore20c.

The relative hardness of the materials of the assembly may contribute to the amount that each structure absorbs and/or transfers axial compression. The material from which the ring is constructed may be selected such that the material of the pipe (for example, metal, such as steel) is relatively harder than the material of the ring (for example, plastic), and the material of the ring is relatively harder than the material of the liner (for example, another plastic relatively softer than that of the ring). The o-ring, if present, may be made of a material that is softer than that of the liner and the ring. In such an embodiment, the ring material can withstand greater compressive loads than the liner flange and take stresses off the flange. The ring material may include one or more of stainless steel, nickel, and carbon steel. For example, the ring material may be nickel coated carbon steel. The ring, if made of softer materials, could yield substantially into a cone, disadvantageously contributing to an imbalance of pressure on the sealing interface. The material may be selected to be sufficiently hard to control compression of the interface pressure on the plastic flange dimensionally, while minimizing yielding of the ring.

Ring20is intended to be compressed between flange12aand the opposite component16, the ring outer diameter is limited to ensure that space is provided for bolts18to extend between flange12aand the opposite component16.

Bore20cmay extend axially from recessed inner face24of first side20ato second side20bof ring20. The bore may have a consistent diameter from one end to the other or may have a diameter that increases or decreases along its length. For example, in one embodiment, it may be useful if the bore diameter tapers where the ring is to be placed between two structures with different inner diameters (such as between a lined pipe and an un-lined pipe). Such tapering may eliminate abrupt diameter changes and thereby reduce erosion caused by shoulders along the pipe flow path. In the illustrated embodiment ofFIG. 7, for example, the diameter across bore increases towards second side20b.The bore may have a cylindrical portion20c′ with a constant diameter axially closer to recessed inner face24, and a flared portion20c″ axially closer to second side20b. This flaring portion20c″ along the bore diameter, where the diameter across the bore at face24is less than the diameter across the bore at second side20b,may act to control stress flow in the ring.

As noted, the second side20bmay have various features. For example, the second side may be formed depending on the type of component16against which the ring20is sealed.

In one embodiment shown inFIGS. 8 and 9, sealing compression ring820may be configured to be couplable to a liner flange on each of its two sides. In other words, a first side820amay be substantially the same as first side20adescribed above, and a second side820bof ring820may be a mirror image of first side820aacross a center plane orthogonal to the center axis of the bore820c.In this illustrated embodiment, bore820cmay be substantially cylindrical, non-tapering. Alternatively, the bore may be tapered, for example, if each side of the ring is to be coupled to a differently sized liner. Each of first side820aand second side820bhas a raised outer annular edge with face822thereon, a recessed inner face824, a step826between the raised outer edge face822and recessed inner face824, and one or more o-ring glands828in the recessed inner face.

FIGS. 1-7illustrate an embodiment with first side20aconfigured to seal against a lined pipe, while second side20bhas a non-recessed surface for sealing against a component16such as any of a standard flange, an end cap, a gasket (such as a spiral wound gasket30, which may include a flat outer disk to centre the gasket, a relatively thicker portion containing a spiral element, and an inner plastic section to act as an initial seal) or even a lined pipe, although the embodiment ofFIG. 8would be preferred for that purpose.

In the embodiment ofFIGS. 1-7, second side20bdefines an annular sealing surface that may be configured to distribute stress on the ring20caused by axial compression, thereby mitigating problems caused by concentrated stress on any given area of the ring. In such an embodiment, second side20bof ring20may be generally convexly shaped. In the illustrated embodiment, for example, second side20bhas a beveled outer edge portion29such that the overall surface of second side20bhas a frustoconical shape at least on its outer circumferential edge. Second side20bmay include a relatively planar, flat inner portion29′ between beveled edge portion29and bore20c.Flat inner portion29′ may, for example, define a plane substantially parallel to the plane of face24. In such an embodiment, the flat inner portion encircles, and is substantially concentric with, bore20cand the beveled edge portion29is the annular area between side wall21and the annular flat inner portion29′. In one embodiment, the bevel at bevelled edge portion29substantially lines up with the location of step26, which in other words means the diameter across step26is about the same as the outer diameter of flat inner portion29′. The bevel at outer edge portion may be gradual such as sloping less than 45 and possibly less than 20 away from the planar surface of portion29′.

Clauses

Clause 1. A sealing compression ring apparatus couplable to a liner and a pipe component, comprising: a body, being substantially annular, having a first side, a second side, and a bore extending from the first side to the second side; the first side including: a raised outer edge portion; a recessed annular portion between the raised outer edge portion and the bore; and an o-ring gland encircling the bore on the recessed annular portion.

Clause 2. The apparatus of any one or more of clauses 1-7, wherein the bore has a tapered diameter that increases from the first side to the second side.

Clause 3. The apparatus of any one or more of clauses 1-7, further comprising an o-ring placed in the o-ring gland.

Clause 4. The apparatus of any one or more of clauses 1-7, wherein the o-ring is made of a material softer than that of the ring.

Clause 5. A pipe assembly, comprising: a base pipe including a flange having a planar face; a liner extending axially within the base pipe and extending radially out and over a portion of the flange to define a liner flange; an opposite flange surface connected by compression fasteners to the flange; and a sealing compression ring apparatus compressed between the flange and the opposite flange surface, the sealing compression ring including a body, being substantially annular, having a first side, a second side, and a bore extending from the first side to the second side; the first side including: a raised outer edge portion; a recessed annular portion between the raised outer edge portion and the bore; an o-ring gland encircling the bore on the recessed annular portion; and an o-ring positioned in the o-ring gland; the raised outer edge portion being in contact with the flange and the o-ring compressed between the liner flange and the recessed annular portion.

Clause 6. The assembly of any one or more of clauses 1-7, wherein the sealing compression ring is constructed of a material selected to be harder than that of the liner and softer than that of the base pipe.

Clause 7. The assembly of any one or more of clauses 1-7, further comprising an annular gasket positioned between the flange-type component and the second side of the sealing compression ring apparatus.