GRADE SEAL SYSTEM AND METHOD OF MANUFACTURING SAME

Abstract

In at least one embodiment, a grade ring system includes an annular shell formed of a plastic composition and defining an annular cavity. An in-situ formed core situated in the annular cavity comprises a plurality of polymer beads expandable by heating medium which, when expanded, substantially fill the annular cavity. A method for forming a grade ring is also disclosed.

Description

TECHNICAL FIELD

The disclosed embodiments relate to a grade seal system and a method of manufacturing same.

BACKGROUND

Often in the construction of a manhole along a street construction firms find it necessary to apply adjustment courses in the immediate area of the manhole cover in order to provide a smooth transition between the manhole cover and the street. Because of frequently heavy use and varying stresses on these adjustment courses, the adjustment courses are prone to rapid deterioration. Substitution of plastic compositions for the materials in previous adjustment courses have not alleviated the deterioration of the adjustment courses as they remain susceptible to ultraviolet light degradation and freeze-thaw forces.

SUMMARY

At least one embodiment, a grade ring system includes an annular shell formed of a plastic composition and defining an annular cavity. An in-situ formed core is formed of a plurality of polymer particles expandable by a heating medium which, when expanded, substantially fill the annular cavity.

In another embodiment, a grade ring system includes a first annular ring comprising a first annular tubular shell formed of a first plastic composition and defining a first cavity. The first annular tubular shell includes a first surface having a protrusion and a second surface being opposed to and spaced apart from the first surface having an embossment. The first cavity is substantially filled with an in-situ expanded polymer bead core. The grade ring system also includes a second annular ring comprising a second annular tubular shell formed of a second plastic composition and defining a second cavity. The second annular tubular shell includes a first surface having a protrusion and a second surface being opposed to and spaced apart from the first surface. The second surface has an embossment. The second cavity is substantially filled with an in-situ expanded polymer bead core. The protrusion of the second annular ring is capable of engaging the embossment of the first annular ring when the first annular ring is vertically stacked upon the second annular ring.

In yet another embodiment, a method for manufacturing a grade ring system component includes the steps of blowmolding a plastic preform in a mold cavity in the shape of an elongated member to form an elongated tubular plastic shell having a longitudinal axis. The elongated member is draw-formed to form at least one annular ring shell in a closed mold. The closed mold has a closing axis that is substantially transverse to the longitudinal axis of the elongated member. The annular ring shell defines a cavity. The annular ring shell receives at least one fill port and a plurality of heating ports in the wall of the annular ring shell. The cavity is filled with expandable polymer particles through the fill port. The expandable polymer particles are expanded to substantially fill the cavity of annular ring shell by injecting a hot, at least partially vaporized, heating medium into the heating ports. The annular ring shell is constrained in the closed mold to limit expansion caused by the heated, expanding polymer particles until the component has cooled sufficiently to limit further expansion. The component is released from the mold.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates an exploded isometric view of a manhole including a grade ring system according to at least one embodiment;

FIG. 2 schematically illustrates a cross-sectional view of a grade ring along axis 2-2 of FIG. 1;

FIG. 3 schematically illustrates a cross-sectional view of a grade ring according to at least one alternative embodiment;

FIGS. 4 a-4c schematically illustrate varying height using a plurality of rings having a wedge shape in side view according to at least one embodiment;

FIG. 5 schematically illustrates a plan view of a grade ring according to at least one other embodiment;

FIG. 6 schematically illustrates a plan view of a grade ring according to at least another embodiment;

FIG. 7 schematically illustrates a cross-sectional view along axis 6-6 of FIG. 5; and

FIGS. 8 a-8e schematically illustrate a process of manufacture of a grade ring system according to at least one embodiment.

DETAILED DESCRIPTION

As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

Except where expressly indicated, all numerical quantities in the description and claims, indicated amounts of material or conditions of reaction and/or use are to be understood as modified by the word “about” in describing the broadest scope of the present invention. Practice within the numerical limits stated should be desired and independently embodied. Ranges of numerical limits may be independently selected from data provided in the tables and description. The description of the group or class of materials as suitable for the purpose in connection with the present invention implies that the mixtures of any two or more of the members of the group or classes are suitable. The description of constituents in chemical terms refers to the constituents at the time of addition to any combination specified in the description and does not necessarily preclude chemical interaction among constituents of the mixture once mixed. The first definition of an acronym or other abbreviation applies to all subsequent uses herein of the same abbreviation and applies mutatis mutandis to normal grammatical variations of the initially defined abbreviation. Unless expressly stated to the contrary, measurement of a property is determined by the same techniques previously or later referenced for the same property. Also, unless expressly stated to the contrary, percentage, “parts of,” and ratio values are by weight, and the term “polymer” includes “oligomer,” “co-polymer,” “terpolymer,” “pre-polymer,” and the like.

It is also to be understood that the invention is not limited to specific embodiments and methods described below, as specific composite components and/or conditions to make, of course, vary. Furthermore, the terminology used herein is used only for the purpose of describing particular embodiments of the present invention and is not intended to be limiting in any way.

It must also be noted that, as used in the specification and the pending claims, the singular form “a,” “an,” and “the,” comprise plural reference unless the context clearly indicates otherwise. For example, the reference to a component in the singular is intended to comprise a plurality of components.

Throughout this application, where publications are referenced, the disclosure of these publications in their entirety are hereby incorporated by reference into this application to more fully describe the state-of-art to which the invention pertains.

As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

Regarding FIG. 1, a manhole system is illustrated having a manhole 12 on which is seated a base grade ring 14. Situated on base grade ring 14 are one or more intermediate grade rings 16. Situated on top of intermediate grade rings 16 is a cap grade ring 18. Base grade ring 14, intermediate grade rings 16 and cap ring 18 comprise a grade ring system 20. In at least one embodiment, the grade ring system may comprise one or more of any of the base grade ring 14, grade ring 16, and/or cap ring 18, such as base grade ring 14 and cap ring 18 or a system embodiment comprising one or more intermediate grade rings 16, which may be in an annular configuration.

In at least one embodiment, intermediate grade rings 16 may include an optional protrusion 22 situated on at least one surface. Intermediate grade rings 16 may also include an optional embossment 24 on a surface. It is preferable that protrusion 22 interlocks with embossment 24 on another ring to assist in positioning intermediate grade rings 16 and/or other rings. A center opening 26 defined by the annular configuration of the grade rings aligns substantially concentrically when one or more intermediate grade rings, such as intermediate grade rings 16, base grade ring 14, and/or cap ring 18, when the rings are stacked vertically upon each other to form the grade ring system 20. It is understood that embossment 24 is illustrated as a recessed embossment, embossments having a raised portion and/or a mixture of raised portions and recessed portions are contemplated in certain embodiments.

It is further preferable that exterior periphery 28 of each grade ring, such as the base grade ring 14, intermediate grade ring 16, and cap grade ring 18, aligns substantially vertically over the exterior periphery 28 of other intermediate grade rings when vertically stacking the rings to form the system 20. Having no substantial steps may be desirable, particularly in situations where the exterior periphery 28 of a first grade ring extends radially a longer distance than the exterior periphery of another grade ring situated below the first grade ring. Having a step may allow freeze-thaw forces to move portions of grade ring system 20 allowing water to enter the manhole and/or contribute to deterioration of the adjustment course (not shown).

Cap grade ring 18 may be adapted to receive a frame 30 and/or a cover 32.

In at least one embodiment, cap ring 18 may have a width ranging from 3 inches to 48 inches. In another embodiment, cap ring 18 may have a width ranging from 4 inches to 10 inches. It is understood that the width dimension of cap ring 18 is illustrative of other grade ring embodiments within the scope and spirit of this invention.

Turning now to FIG. 2, a cross-sectional view of at least one embodiment of intermediate ring 16 is illustrated. Intermediate ring 16 comprises a thermoplastic shell 40 that defines a cavity 42. Cavity 42 is substantially filled with a core 44 filled with expanded polyolefin beads 46. It should be understood that such a cross-sectional view may also be illustrative of other grade rings, such as base grade ring 14 or cap grade ring 18.

Intermediate ring 16 further includes a first surface 48 that is opposed to and separated from a second surface 50. Exterior periphery surface 28 is opposed to and spaced apart from interior periphery surface 52.

The cross-section of FIG. 2 when revolved around a central axis exterior to the cross-section forms a circular annular ring. The width of cross-section, such as between surfaces 28 and 52, may range from 1 inch to 4 inches in at least one embodiment. In another embodiment, the width of ring 18 ranges from 2 inches to 3 inches.

In at least one embodiment, the height of cross-section between surface 48 and surface 50 ranges from 0.75 inches to 6 inches. In another embodiment, the height of the cross-section ranges from 1 inch to 5.5 inches.

A thickness of shell 40 may range from 0.03 inches to 0.5 inches in at least one embodiment. In another embodiment, the thickness of shell 40 may range from 0.125 inches to 0.25 inches.

Core 44 may include steam-expandable polymer beads, which when expanded in-situ within the shell 40, form expanded polymer beads 46. In at least one embodiment, the expanded polymer beads include expanded polyolefin beads. In another embodiment, the expanded polyolefin beads includes expanded polypropylene polymer beads (EPP) in core 44. In yet another embodiment, core 44 includes expanded high molecular weight polypropylene polymer beads. In yet another embodiment, homopolymer beads are included in the expanded polyolefin beads in order to increase the stiffness of core 44. As a non-limiting example, when the homopolymer polyolefin is a homopolymer polypropylene, the stiffness increases such that a 100,000 lb load yields a strain less than 5.8% and a compression set of less than 0.07 inches. It is understood that a portion of core 44 may comprise polyolefin beads in an unexpanded configuration or a partially expanded configuration without exceeding the scope and spirit of the contemplated embodiments.

Shell 40 may be formed from a polymeric composition. The polymeric composition may include a recyclable thermoplastic composition. Non-limiting examples of the polymeric composition suitable for shell 40 include polyolefins, such as polypropylene and polyethylene.

In certain embodiments, especially when cold, shell 40 includes a blend of a non-polyolefin thermoplastic polymer and polyolefin (NPTP/PO), such as a thermoplastic polyolefin/polypropylene blend, a thermoplastic elastomer/polypropylene blend, a thermoplastic polymer having a glass transition temperature less than −80° C. and polyolefin blend, a thermoplastic polymer having a glass transition temperature less than −20° C. and polyolefin blend, a thermoplastic vulcanizate/polyolefin blend, and a heterogeneous polymer blend.

In certain embodiments, heterogeneous polymer blends have a crystalline thermoplastic phase and a high molecular weight and/or crosslinked elastomeric phase such as supplied by ExxonMobil or Advanced Elastomer Systems.

In at least one embodiment, the heterogeneous polymer blend includes the non-crystalline polyolefin thermoplastic polymer ranges from 5 wt. % to 70 wt. % of the amount of blend. In another embodiment of the heterogeneous polymer blend, the amount of the non-crystalline thermoplastic polymer ranges from 10 wt. % to 40 wt. %.

In at least one embodiment, the ratio of non-polyolefin thermoplastic polymer to polyolefin in the NPTP/PO blend ranges from 0.1 to 10 in the heterogeneous polymer blend. In another embodiment, the ratio of non-polyolefin thermoplastic polymer to polyolefin in the NPTP/PO blend ranges from 0.2 to 5. In yet another embodiment, the ratio of non-polyolefin thermoplastic polymer to polyolefin ranges from 0.3 to 2.

The core 44, when comprised of EPP steam-bonded to the shell 40, has an ability to withstand greater than 80 lbf/in2 dynamic load, such as an AASHTO H-20 wheel loading specification.

The core 44, when comprised of EPP steam-bonded to the shell 40, has the ability to withstand greater than 21,280 lbf static load when tested according to the method in AASHTO HS-25 highway bridge specification.

When the grade ring system is assembled with the base ring 14, the intermediate ring 16, the cap ring 18 and with sealant bead 34 between each ring, water penetration tests showed no leakages at less than 3″ of hydrostatic head.

The intermediate grade ring 16 has a weight for a 32″ outside diameter ring with a 24″ inside diameter as follows in Table 1.

	TABLE 1
	Height		Weight	Prior Art Weight
	3″	10-20	lbs	92	lbs
	6″	20-40	lbs	183	lbs
	12″	40-160	lbs	366	lbs

A heating medium, such as steam, super-heated steam, or partially vaporized steam, may be injected into unexpanded or partially expanded polyolefin beads. Expanded polyolefin beads, such as EPP, may have a density ranging from 1 lb per cubic foot to 20 lbs. per cubic foot. In yet another embodiment, steam-expanded EPP may have a density ranging from 1.5 lbs per cubic foot to 10 lbs. per cubic foot. In yet another embodiment, steam-expanded EPP may have a density ranging from 2 lbs. per cubic foot to 6 lbs. per cubic foot. In another embodiment, steam-expanded EPP may have a density ranging from 3 lbs. per cubic foot to 5 lbs. per cubic foot.

The steps of expanding unexpanded or partially expanded beads using a heating medium are illustrated by U.S. patent application Ser. Nos. 13/358,181, 13/005,190, and 12/913,132, all of which are hereby incorporated by reference

Turning now to FIG. 3, in at least one embodiment, a wedge-shaped grade ring 60 is illustrated. In at least one embodiment the wedge may have a angle, theta, ranging from 0.5° to 10°. In at least another embodiment, the wedge-shaped ring 60 may have an angle ranging from 2° to 7°. Wedge-shaped ring 60 in at least one embodiment may have a first wall 62 and a second wall 64 that define the annular ring as well as cavity 42 into which core 44 is formed in-situ by using a heating medium to expand unexpanded and/or partially expanded polymer beads.

While embossment 24 is illustrated in at least one embodiment, it should be understood that other means of inducing cooperation and/or fastening wedge-shaped grade rings to one another may be used without exceeding the scope or spirit of the invention. Non-limiting examples of cooperative structures include a retention structure, such as a cover having a diameter exceeding the diameter of the cap ring 18 or intermediate grade ring 16, protrusions cooperating with embossments on other rings, a permanent alignment fixture, an adhesive, adhesively-applied structures, alignment pins, and/or a removable alignment fixture. For another example, FIG. 3 includes the optional sealant bead 34 positioned to engage a seal between embossment 24 and another surface. It should be understood that sealant bead 34 may include an adhesive composition and/or may be formed in any shape needed, such as a strip, intermittent drops, tape or roll.

Turning now to FIGS. 4a to 4c, a first wedge-shaped grade ring 60 is mounted on a second wedge-shaped grade ring 60. By rotating the first wedge-shaped grade ring 60 relative the second wedge-shaped grade ring 60 the angle φ of one exterior surface relative to the other may be varied in a range from 0° to 20° in at least one embodiment. The maximum height of the combined grade rings 60 may also be varied during rotation, starting with a nominal height, ho. At approximately 90° of rotation, the overall maximum height is given by equation [3]

hmax=ho+h1  [3]

where h1 is the increased height relative to h0 as shown in FIG. 4b.

At approximately 180° of rotation, the overall maximum height is maximized and is given by equation [4]

hmax=h0+h2  [4]

where h2 is the increased height relative to h0 shown in FIG. 4c, and representing the maximum height increase at 180° of rotation of the first grade ring 60 relative to the second grade ring 60.

Regarding FIG. 5, a grade ring having an alignment flange 66 is schematically illustrated. Situated in alignment flange 66 is an alignment aperture 68 suitable for use with guide pins (not shown). The guide pins may be used, in at least one embodiment, to orient the intermediate grade rings 16 when vertically stacked.

Turning now to FIG. 6, a retrofit grade ring 70 is schematically illustrated. In at least one embodiment, retrofit grade ring 70 may be suitable for a repair of a manhole or a pit. Non-limiting examples of pits include a restaurant grease interceptor or a jet fuel pumping pit or a temporary ramp ring used in road resurfacing. In certain examples, it is desirable not to have to remove a buried pit when replacing the original manhole cover. In this exemplary situation, it is useful to place a new manhole cover above the existing manhole cover in order to affect better sealing of the pit. However, the replacement manhole cover now is several inches above the grade of the tarmac. In order to avoid chipping out cement around the manhole cover, the retrofit grade ring 70, such as illustrated in FIG. 6, may be applied directly to the tarmac and secured with fasteners or adhesive. As illustrated, center opening 72 is defined by the relatively rectangular annular shell. It is understood that central opening 72 may be of any geometry needed to mate with the manhole cover and is not limited to having an enclosed annulus.

FIG. 7 is a cross-sectional view along axis 7-7 of FIG. 6. FIG. 6 includes a core having more than one density of expanded polymer bead. In a first density zone 74, the expandable polymer beads may have a density that is at least one pound per cubic foot less than the density of expanded polymer beads in the second density zone 76. It is understood that there may also be a density gradient exceeding 1 lb/ft3 across the cross-section without a definitive segmentation into zones.

Turning now to FIGS. 8a-8e, a method is illustrated for forming a component of a grade ring system such as a grade ring 16 and/or base grade ring 14. Using blowmolding tooling a paracen 80 is formed as shown in FIG. 8a. Parison 80 defines a cavity 82 and a longitudinal axis 84 in step 86. Turning now to FIG. 8b, in at least one embodiment, step 88 includes draw forming of at least one annular ring shell in a closed mold 90 having at least two portions 92 and 94. During draw forming the mold 90 includes two mold portions 96 and 98 capable of forming an annular ring.

Mold portion 92 and 94 are closed about an axis substantially transverse to the longitudinal axis 84 of parison 80. In at least another embodiment, mold 90 may include a plurality of mold portions without exceeding the scope and spirit of the invention. It is understood that while a annular ring is illustrated, other geometric shapes may be produced by the same process. Non-limiting examples of other geometric shapes include a box frame and a cup having no center opening.

In step 100 of FIG. 8c, at least one fill port 102 is formed through mold portion 92 to allow unexpanded polymer beads 104 from a supply 106 to be fed into a cavity 108 formed by mold portions 96 and 98.

The heating mechanism, such as steam, is supplied in FIG. 8d, step 120, from steam manifold 122, in at least one embodiment. The steam is directed to a plurality of steam ports, such as steam port 124. Spacing between steam injection needles may vary with the density of unexpanded beads because the steam migration is limited. In at least one embodiment, the spacing between adjacent steam injection needles ranges from 1 inch to 6 inches. In another embodiment, the spacing between adjacent steam injection needles ranges from 2 inches to 5 inches. In yet another embodiment, the spacing between adjacent steam needles ranges between the distances defined by equation [1] and [2].

$\begin{array}{cc}{D}_1=\frac{1}{\left(\mathrm{ABD}\times 0.56\right)}-0.5& \left[1\right]\\ D_2=\frac{1}{\left(\mathrm{ABD}\times 5\right)}+3& \left[2\right]\end{array}$

wherein D1 is the minimum distance in inches between steam injection needles and D2 is the maximum distance in inches between steam injection, ABD is on average apparent bulk density of unexpanded and/or partially expanded polymer particles suitable for comprising core 44.

In at least one embodiment, the average apparent bulk density of the unexpanded and partially polymer particles ranges from 0.15 lbs/ft3 to 4 lbs/ft3. In another embodiment, the average apparent bulk density of the unexpanded and partially expanded polymer particles ranges from 0.2 lbs/ft3 to 2 lbs/ft3.

Unexpanded expandable beads 104 are expanded by the addition of steam, such as super-heated steam. Expanded beads 126 substantially fill cavity 108. The annular ring remains constrained in mold halves 92 and 94 until it is sufficiently cooled to limit further expansion.

In at least one embodiment, as shown in step 130 and FIG. 8e, the mold portions 92 and 94 are opened to release the grade ring component 132 (shown in cross-section). Grade ring component 132 comprises expanded polymer beads and the annular shell 40. Grade ring component 132 comprises a component of grade ring system 20.

While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.

While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.

Claims

1. A grade ring system comprising: an annular shell formed of a plastic composition and defining an annular cavity;an in-situ formed core situated in the annular cavity comprising a plurality of polymer particles expandable by a heating medium which, when expanded, substantially fill the annular cavity.

2. The grade ring system of claim 1 wherein the plastic composition is a thermoplastic polymer composition.

3. The grade ring system of claim 1 wherein the plastic polymer composition comprises a polypropylene composition.

4. The grade ring system of claim 1 wherein the expandable polymer particles comprise a polyolefin particles.

5. The grade ring system of claim 1 wherein the expandable polymer particles comprise expanded polypropylene particles.

6. The grade ring system of claim 1 wherein the expandable polymer particles comprise homopolymer beads.

7. The grade ring system of claim 1 wherein the expandable polymer particle comprises a steam-expandable polymer bead.

8. The grade ring system of claim 1 wherein the heating medium comprises super-heated steam.

9. The grade ring system of claim 1 wherein the elongated annular shell ranges in height from 0.75 inches to 6 inches.

10. The grade ring system of claim 1 wherein the diameter of the annular shell ranges from 1 inch to 10 inches.

11. The grade ring system of claim 1 wherein the annular ring has opposed, spaced-apart first and second surfaces, the first surface includes a protrusion and the second surface includes a recessed embossment.

12. The grade ring system of claim 1 wherein the annular ring has opposed, spaced-apart first and second surfaces, the first and second surfaces are substantially parallel and situated at an angle relative to the outer wall of the elongated annular ring.

13. The grade ring system of claim 1, wherein the annular ring has a varying height to define wedge shape in side view.

14. The grade ring system of claim 13 wherein the wedge-shaped annular ring has opposed, spaced-apart first and second surfaces, the first and second surfaces being situated relative to each other at an angle ranging from 0.5 degrees to 10 degrees to allow alignment with angles of a street surface.

15. A grade ring system comprising: a first annular ring comprising a first annular tubular shell formed of a first plastic composition and defining a first cavity, the first annular tubular shell including a first surface having a protrusion and a second surface being opposed to and spaced apart from the first surface, the second surface having an embossment, the first cavity being substantially filled with an in-situ expanded polymer bead core; anda second annular ring comprising a second annular tubular shell formed of a second plastic composition and defining a second cavity, the second annular tubular shell including a first surface having a protrusion and a second surface being opposed to and spaced apart from the first surface, the second surface having an embossment, the second cavity being substantially filled with an in-situ expanded polymer bead core, wherein the protrusion of the second annular ring being capable of engaging the embossment of the first annular ring when the first annular ring is vertically stacked up on the second annular ring.

16. The system of claim 15, further comprising a base grade ring having a base annular tubular shell formed of a third plastic and defining a base grade ring cavity, the base annular tubular shell including a base surface having a protrusion, the base cavity being substantially filled with an in-situ expanded polymer bead core, wherein the base grade ring is capable of engaging the embossment of the second annular ring when the second annular ring and the base annular ring are vertically stacked adjacent to one another.

17. The system of claim 15, further comprising a cap ring having a cap annular tubular shell formed of a one or more layers of plastic and defining a cap ring cavity, the cap annular tubular shell including a cap surface having a embossment, the cap ring cavity being substantially filled with an in-situ expanded polymer bead core, wherein the cap ring is capable of engaging the protrusion of the first annular ring when the first annular ring and cap annular ring are vertically stacked adjacent to one another.

18. The system of claim 15, wherein the first surface of either the first or second annular ring is disposed at an angle relative to the second surface of the same annular ring, the angle ranging from 0.5 degrees to 10 degrees.

19. The system of claim 15 further comprising a seal disposed between the embossment of the first annular ring and the protrusion of the second annular ring.

20. The system of claim 15, wherein a radius of the first annular ring equals or exceeds the radius of the second annular ring, when the first annular ring is disposed above the second annular ring.

21. The system of claim 15, wherein at least one annular ring has a thickness ranging from 0.75 inches to 6 inches.

22. A method for manufacturing a grade ring system component comprising the steps of: (a) extruding a plastic preform in a mold cavity in the shape of an elongated member to form a tubular plastic shell having a longitudinal axis;(b) forming the tubular plastic shell to form at least one annular ring shell in a closed mold having a closing axis substantially transverse to the longitudinal axis, the annular ring shell having a wall defining a cavity;(c) forming at least one fill port and a plurality of heating ports in the wall of the annular ring shell;(d) filling the cavity through the fill port with expandable polymer particles;(e) injecting a hot, at least partially vaporized, heating medium into the heating ports to expand the expandable polymer particles so as to substantially fill the cavity of the annular ring shell to form the component;(f) constraining the annular ring shell in the closed mold to limit expansion caused by the heated, expanding polymer particles until the component has cooled sufficiently to limit further expansion; and(g) releasing the component from the mold cavity.

22. The method of claim 21, further comprising the steps of: (h) forming at least two components; and(i) stacking at least two components to form the grade ring system.

23. The method of claim 22, further comprising the steps of: (j) forming at least one wedge-shaped component wherein the component has a first surface disposed at an angle relative to an opposed second surface, the angle ranging from 0.5 degrees to 10 degrees;(k) situating the first wedge-shaped component on or within the grade ring system; and(l) adjusting the grade ring system height or angle relative to a street surface when rotating the first wedge-shaped component such that the angle of the wedge-shaped component cooperates with an angle of the street surface to form a substantially smooth transition between the grade ring systems and the street.

24. The method of claim 23, further comprising: (m) situating a second wedge-shaped component in an inverted position on the first wedge-shaped component;(n) rotating the second wedge-shaped component relative to the first wedge-shaped component to achieve the grade angle or height of the street surface.

25. The method of claim 21, wherein the heating ports include steam injection needles are spaced apart having a spacing ranging from D1 to D2, where