Patent Application
20190157798
The disclosure relates generally to sealed enclosures and more particularly to enclosures for optical fibers, copper lines, or other optical or electrical telecommunications equipment having a watertight seal created at least in part through the use of superabsorbent polymers. Large distribution cables carrying multiple optical fibers or copper lines deliver telecommunication service to distribution nodes, such as to a neighborhood subdivision or a business park. The optical fibers or copper lines are subdivided into branches of single fibers (or copper lines) or groups of fibers (or groups of copper lines) that are spliced or otherwise coupled to drop cables running to homes or businesses. The splice points are contained in an enclosure that may, for example, be suspended from a utility pole. Such enclosures are often, thus, exposed to precipitation and widely varying temperatures. Nevertheless, these enclosures are expected to have a service life of at least five years, while not allowing water to enter the enclosure and degrade the copper lines or optical fibers.
In one aspect, embodiments of an equipment enclosure are provided. The equipment enclosure includes a first portion having a first sealing surface and a second portion having a second sealing surface. The first portion and the second portion define an internal cavity when the first portion and the second portion are in a closed configuration. The equipment enclosure also includes a first gasket mounted to either the first sealing surface or the second sealing surface and superabsorbent polymer (SAP) located on at least one of the first portion and the second portion. In some embodiments, an optical, electrical, or opto-electrical component is located within the internal cavity of the equipment enclosure.
In another aspect, embodiments of a system for sealing an enclosure are provided. In particular, the enclosure has a first portion and a second portion that define an internal cavity. The system includes a first gasket and a second gasket. The first gasket is made, at least in part, of SAP, and the first gasket circumscribes the internal cavity. The second gasket circumscribes the first gasket, and further, the first gasket is capable of absorbing from 50 grams to 1000 grams of water per gram of SAP.
In still another aspect, embodiments of an enclosure are provided. The enclosure includes a first portion having a sealing surface and a second portion. The first portion and the second portion define an internal cavity when the first portion and the second portion are in a closed configuration. The enclosure also includes a first gasket made, at least in part, of SAP, and the first gasket is mounted to the second portion in such a way as to oppose the sealing surface in the closed configuration. Further, the first gasket is configured to prevent ingress of water while the enclosure is submerged under 15 cm of water for 30 min.
Additional features and advantages will be set forth in the detailed description that follows, and in part will be readily apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understand the nature and character of the claims.
The accompanying drawings are included to provide a further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and the operation of the various embodiments.
The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:
While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.
Referring generally to the figures, various embodiments of a telecommunications enclosure including a region of superabsorbent polymer are provided. Generally, telecommunications enclosures are deployed in ways that subject them to highly variable weather conditions. For example, telecommunications enclosures may experience temperature cycling from −40° C. to 70° C. as well as various forms and amounts of precipitation. Such telecommunications enclosures are nevertheless expected to have long operation lives (e.g., 5 to 20 years or more) while also not experiencing leaks that might otherwise damage the cables, fibers, and other components contained therein. As disclosed herein, superabsorbent polymers are utilized to replace or supplement sealing gaskets to restrict or prevent water from seeping into the interior of the telecommunications enclosure. In various exemplary embodiments, the superabsorbent polymer is applied in one or more strips of tape at a first end, a second end, or at both the first and second ends of the enclosure, as a redundant sealing feature. While an telecommunications enclosure is used herein to facilitate description of the inventive concepts, the present disclosure relates to other forms of enclosures, terminals, cabinets, or other water-resistant products or portions of a product where a water resistant or watertight sealing is desired for at least a portion of the product. The embodiments described herein are presented by way of example, and not by way of limitation, and a person having ordinary skill in the art will recognize from the present disclosure other embodiments falling within the scope of the invention.
As shown in
In the embodiment depicted, the enclosure 10 includes a first portion, which is depicted as a bin portion 12, and a second portion, which is depicted as a lid 14. As shown in
Returning to the rectangular prism embodiment depicted in
In
In embodiments, the first peripheral gasket 28 is made from an elastomeric material or reversibly deformable material, such as natural rubber, isoprene, ethylene propylene diene (EPDM), nitrile rubber (copolymer of butadiene and acrylonitrile), styrene butadiene rubber (SBR), silicone, butyl rubber, polybutadiene, and urethane, for example. In another embodiment, the first peripheral gasket 28 is a thermoplastic elastomer, such as an ionomer or block copolymer (e.g., syrene-butadiene-sytrene block copolymer).
In embodiments, the peripheral gasket 28 has a cross-sectional width of from 1 mm to 10 mm. In particular embodiments, the peripheral gasket 28 has a cross-sectional width of from 4 mm to 6 mm. The width refers to the widest measurement across the cross-section, which can be circular, rectangular, oval, elliptical, or another polygonal or curved shape.
The first peripheral gasket 28 of the embodiment in
In certain circumstances, the molding of the components of the telecommunications enclosure 10 can create sink marks (i.e., slight undulations instead of a perfectly flat or planar surface), especially along the first or second peripheral surfaces 17, 18, as a result of shrinkage during the molding process. These sink marks are a potential source of leakage of fluids into the interior of the telecommunications enclosure 10 over time. Additionally, because the telecommunications enclosure 10 may be exposed to temperatures as low as −40° C. and as high as 70° C., the thermal expansion and/or contraction of the different components or parts of the lid 14 and bin portion 12 at different rates can exacerbate the effect of sink marks. For example, at cold temperatures, the elastomeric material of the first peripheral gasket 28 may pull back, deform less, or not fill such sink marks as fully as at higher temperatures. Further, at high temperatures, the expansion of the components can create larger gaps between sealing surfaces such as the first and second peripheral surfaces 17, 18.
For example,
Indeed, a second experiment in which the above referenced telecommunications enclosure was submerged under 15 cm of water at room temperature for 30 minute. Before submerging the telecommunications enclosure 10 under water, the telecommunications enclosure 10 was clamped closed to create a seal between the first peripheral surface 17, the second peripheral surface 18, the first peripheral gasket 28, and the seal line 30. Upon opening the telecommunications enclosure 10 after removing it from the water at the end of the 30 minute time period, some water could be seen in the internal cavity 20 of the telecommunications enclosure 10.
In order to limit or restrict, or in some cases eliminate, fluid leakage into the telecommunications enclosure for the useful life of the enclosure 10, superabsorbent polymer (SAP) may be applied at various locations of the telecommunications enclosure 10 as further described herein. As used herein, the term superabsorbent polymer (or SAP) means a material comprising a water-swellable polymer that can absorb and retain from about 50 grams to about 1,000 grams of water per gram of the material. Thus, the term superabsorbent polymer or SAP, as used herein, includes materials or combinations of materials that are not entirely polymers. For example, the term superabsorbent polymer or SAP as used herein includes a non-polymer binder having a water-swellable polymer dispersed therein.
In the embodiment of
Returning to the embodiment shown in
In some embodiments, one or more of the locations 50a, 50b, 50c, and 50d are recessed into the peripheral surfaces 17, 18 so that the SAP is located within the recesses. In other embodiments, one or more of the locations 50a, 50b, 50c, and 50d are coplanar with the peripheral surfaces 17, 18 so that the SAP is located at the surface of the peripheral surfaces 17, 18. When the SAP at one or more of locations 50a, 50b, 50c, or 50d is recessed into the peripheral surfaces 17, 18, the SAP is not compressed or experiences relatively less compression than when the SAP one or more of the locations 50a, 50b, 50c, or 50d, respectively, sits on the surface of the peripheral rim 18 or lid 14. That is, when the SAP at location 50a, location 50b, location 50c, or location 50d sits on the surface of the peripheral surfaces 17, 18, the SAP is compressed, at least in part, either between the lid 14 and the bin portion 12, or between the lid 14 or bin portion 12 and the first peripheral gasket 28 when the lid 14 and the bin portion 12 are in a closed configuration. In other embodiments, the SAP is located such that is it not between the first peripheral surface 17, the second peripheral surface 18, or the first peripheral gasket 28 when the lid 14 and the bin portion 12 are in a closed configuration.
The SAP may be in the form of a powder, fabric, tape, hot melt, dispursed in the material of a grommet, or other form factor. Referring again to
Further, while
At each location 50a, 50b, 50c, 50d, the SAP can have a thickness of up to 10 mm in some embodiments. In other embodiment, the SAP and/or SA-SHM has a thickness of up to 5 mm, and in still other embodiments, the SAP and/or SA-SHM has a thickness of up to 2 mm. The SAP has a thickness of at least 0.05 mm in embodiments.
In a particular embodiment, SAP tape was applied on the surface of the peripheral rim 18 at locations 50a, 50b, and the second experiment was performed again. More specifically, after applying the SAP tape, the telecommunications enclosure 10 was again clamped closed to create a seal between the peripheral gasket 28, seal line 30, the SAP tape at locations 50a, 50b, and the peripheral rim 18. After clamping the telecommunications enclosure 10, the telecommunications enclosure 10 was submerged under 15 cm of water at room temperature for 30 minutes, and upon opening the telecommunications enclosure 10 at the end of the test, substantially no water had penetrated the internal cavity 20 of the telecommunications enclosure 10. That is, the SAP tape was able to prevent the ingress of water into the internal cavity 20 of the telecommunications enclosure 10 during the test. This test, in which the closure is submerged in 15 cm of water at room temperature for 30 minutes, may, in some instances, be used to predict the performance of the telecommunications enclosure 10 over some or all of its operational or useful lifetime, depending on the intended location and use for the enclosure 10. The use of SAP in its various forms and compositions described herein as part of the telecommunications enclosure 10 is designed to prevent the ingress of water into the internal cavity 20 of the telecommunications enclosure 10 during its operational lifetime. In some circumstances, the operational life of the telecommunications enclosure 10 is from five to twenty years. After the operational life of the telecommunications enclosure 10, applicants believe that the SAP continues to substantially prevent the ingress of water into the internal cavity 20 of the telecommunications enclosure 10, and any ingress of water into the internal cavity 20 is believed to be minimal.
In the depicted embodiment, a second SAP gasket 62 is provided near the second end 32 of the enclosure 10′ and is circumscribed by the peripheral gasket 28 and the seal line 30. In embodiments, the second SAP gasket 62 has a cross-sectional width of from 1 mm to 10 mm. In particular embodiments, the second SAP gasket 62 has a cross-sectional width of from 4 mm to 6 mm. As with the first SAP gasket 60, the width refers to the widest measurement across the cross-section, which can be circular, rectangular, oval, elliptical, or another polygonal or curved shape. Further, in some embodiments, the first SAP gasket 60 and the second SAP gasket 62 have different widths or shapes or different widths and shapes. Moreover, the widths, and shapes of the first SAP gasket 60 and the second SAP gasket 62 can be different from the width or shape of the peripheral gasket 28.
Additionally, in some embodiments, at least one of the first SAP gasket 60 and the second SAP gasket 62 abuts or contacts the peripheral gasket 28 when the SAP gaskets 60, 62 are not exposed to a liquid. However, in other embodiments, neither of the first SAP gasket 60 and the second SAP gasket 62 abuts or contacts the peripheral gasket 28 when the SAP gaskets 60, 62 are not exposed to water or another fluid, which provides additional room for the first SAP gasket 60 or second SAP gasket 62 to expand when exposed to water or another fluid. In each of the described embodiments, the SAP gaskets 60, 62 helps to prevent ingress of water into the internal cavity 20.
Still further, in embodiments, the peripheral gasket 28 has an open cell porosity, i.e., interconnected pores. Open cell porosity would allow water to transfer through pore conduits to one or both of the first SAP gasket 60 and the second SAP gasket 62, causing the SAP gasket 60 or SAP gaskets 60, 62 to swell. In some embodiments, the SAP gasket 60 or SAP gaskets 60, 62 would swell and enter and close off the pores of the peripheral gasket 28, creating an interlock between one or both of the first SAP gasket 60 and the second SAP gasket 62 and the open cell peripheral gasket 28. However, in other embodiments, the peripheral gasket 28 has a closed cell porosity, i.e., pores substantially closed off from each other, such that substantially no water (or other fluid) is able to transport through the peripheral gasket 28.
The secondary peripheral gasket 64 helps maintain the positioning of the first SAP gasket 60 in the case that the SAP gasket 60 absorbs a large amount of water (or other fluid) and swells. Further, in embodiments, one or both of the peripheral gasket 28 and the secondary gasket 64 has an open cell porosity. Open cell porosity would allow water to transfer through pore conduits to the SAP gasket 60, causing the SAP gasket 60 to swell, and the SAP gasket 60 would enter and close off the pores, creating an interlock between the SAP gasket 60 and the open cell peripheral gasket 28 and/or the secondary peripheral gasket 64. However, one or both gaskets 28, 64 in other embodiments may have a closed cell porosity.
In yet another embodiment shown in
The SAP for use in the telecommunications enclosures described above may take many forms. As described above, the SAP may be in the form of a tape, a hot melt, an SAP gasket, a powder, or some other configuration. In addition, the SAP used may itself take many forms and may have many compositions. However, generally, the water absorption capacities of the SAP used in the embodiments of the telecommunications enclosures disclosed herein will be greater than 50 grams of water absorbed per gram of SAP and less than about 1,000 grams of water absorbed per gram of SAP. In other embodiments, the water absorption capacity of the SAP is greater than 100 grams of water absorbed per gram of SAP. In still other embodiments, the water absorption capacity of the SAP is greater than 150 grams of water absorbed per gram of SAP. In yet other embodiments, the water absorption capacity of the SAP is greater than 200 grams of water absorbed per gram of SA-SHM. Further, the SAP may have a maximum water absorption capacity of 500 grams of water absorbed per gram of SAP. In other embodiments, the SAP used may have a maximum water absorption capacity of 1000 grams of water absorbed per gram of SAP. In yet other embodiments, the SAP has a water absorption capacity maximum of about 400 grams of water per gram of SAP or SA-SHM.
As mentioned above, the SAP gaskets 60, 62 are made of SA-SHM in certain embodiments. In such embodiments, the SA-SHM is comprised of a hot melt matrix in which one or more SAP powders are suspended. As discussed above, the SAP powders may be distributed throughout the thickness of the hot melt matrix and not just on a surface of the hot melt or not just to a certain depth of the hot melt. In this way, the hot melt matrix additionally provides a connective matrix by which to keep the coating together when the SAP powders expand upon contacting water or another fluid.
In some embodiments, the SA-SHM used are physically setting thermoplastic materials. For example, these may include commercially available water-swellable hot melt adhesives such as HM002 and HM008B (available from Stewart Superabsorbents, Hickory, N.C.), Technomelt AS 4415 (also known as Macromelt Q 4415 available from Henkel Corp., Madison Heights, Mich.), and NW1117 and NW1120B (Hydrolock® super absorbent thermoplastic available from H. B. Fuller Company, Vadnais Heights, Minn.).
Additionally, a variety of exemplary SAP compositions are provided in the following paragraphs. According to one embodiment, the SAP is a SA-SHM, and the SA-SHM includes three components that are mixed homogenously. The first component is a water-insoluble component containing at least one water-insoluble polymer or copolymer and at least one other substantially water-insoluble resin. For example, the first component can be selected from polyamides, copolyamides, polyaminoamides, polyesters, polyacrylates, polymethacrylates, polyolefins and ethylene/vinyl acetate (EVA) copolymers. Further the first component can be mixtures of one or more of the foregoing polymers. The second component is a water-soluble or water-dispersible component containing at least one water-soluble or water-dispersible oligomer and/or polymer or copolymer. For example, the second component can be selected from polyethylene glycols with molecular weights of 400 to 20,000, polyvinyl methyl ether, polyvinyl pyrrolidone, copolymers of vinyl methyl ether or vinyl pyrrolidone, polyvinyl alcohols, water-soluble or water-dispersible polyesters or copolyesters, and water-soluble or water-dispersible acrylate polymers.
The third component is a water-swellable component consisting of a water-swellable homopolymer or copolymer. For example, the third component can be selected from any homopolymers and/or copolymers which, as hydrophilic materials, are capable of absorbing and retaining large amounts of water, even under pressure, without immediately dissolving in the water, including, for example, graft copolymers of starch or cellulose with acrylonitrile, acrylic acid or acrylamide, carboxymethyl cellulose, maleic anhydride/poly-α-olefin copolymers, polyacrylamide, polyacrylic acid and salts of polyacrylic acid, and, optionally, copolymers of acrylic acid or acrylamide with acrylate esters. In embodiments, other suitable the third components include homopolymers and copolymers of acrylic acid or methacrylic acid, acrylonitrile or methacrylonitrile, acrylamide or methacrylamide, vinyl acetate, vinyl pyrrolidone, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, vinyl sulfonic acid or hydroxyalkyl esters of such acids, 0 to 95% by weight of the acid groups being neutralized with alkali or ammonium groups and these polymers/copolymers are crosslinked by means of polyfunctional compounds. Graft copolymers of starch or cellulose with the above comonomers can also be used in certain embodiments. Still other suitable superabsorbent polymers include crosslinked acrylate polymers, crosslinked products of vinyl alcohol-acrylate copolymers, crosslinked products of polyvinyl alcohols grafted with maleic anhydride, cross-linked products of acrylate-methacrylate copolymers, crosslinked saponification products of methyl acrylate-vinyl acetate copolymers, crosslinked products of starch acrylate graft copolymers, crosslinked saponification products of starch acrylonitrile graft copolymers, crosslinked products of carboxymethyl cellulose polymers, and crosslinked products of isobutylene-maleic anhydride copolymers.
In some embodiments, the SA-SHM also includes a tackifying resin or resins to increase the tackiness of the melt. In particular embodiments, various colophony derivatives, i.e., in particular the resin esters of abietic acid, are used for the tackifying resin; although, in other embodiments, other polyterpenes and terpene/phenol resins are used. Other colophony derivatives include colophony esters of various mono- and poly-functional alcohols. Additionally, suitable tackifying resins include wood rosin, tall oil rosin, tall oil derivatives, gum rosin, rosin ester resins, natural terpenes, synthetic terpenes, and petroleum based tackifying agents, including, e.g., aliphatic, aromatic and mixed aliphatic-aromatic petroleum based tackifying resins. Still further, other suitable tackifying resins include, e.g., alpha-methyl styrene resins, branched and unbranched C5 resins, C9 resins and C10 resins, styrenic and hydrogenated modifications thereof, and combinations thereof.
In particular embodiments, the SA-SHM contains the following components: 15 to 45% by weight of resin esters or terpene/phenol resins; 15 to 40% by weight of thermoplastic copolymer, more particularly ethylene/vinyl acetate copolymer; 5 to 20% by weight of acrylate copolymers; 5 to 30% by weight of polyethylene glycols; 5 to 15% by weight of polyvinyl ethyl ethers, water-soluble or water-dispersible acrylate polymers or water-soluble or water-dispersible copolyesters; 15 to 50% by weight of powder-form polyacrylic acid salt, polyacrylamide or similar powdered superabsorbent polymer; and 0.2 to 2.0% by weight of stabilizers, such as, for example, antioxidants based on sterically hindered phenols, that enhance the temperature stability of the compositions.
In other particular embodiments, the SA-SHM contains the following components: 15 to 45% by weight of resin esters, terpene/phenol resins or the like; 15 to 40% by weight of thermoplastic polymer or copolymer, more particularly ethylene/vinyl acetate copolymer; 5 to 25% by weight of polyethylene glycols; 15 to 50% by weight of a powdered superabsorbent polymer, more particularly polyacrylic acid salt; 0.2 to 2.0% by weight of a stabilizer; and 0.5 to 5.0% by weight of waxes, more particularly ethylene bis-stearamide.
In another embodiment of a suitable SA-SHM composition, the SA-SHM is comprised of 10 to 25% by weight of at least one tackifying resin, 20 to 40% by weight of at least one water-dispersible EVA wax, 5 to 25% by weight of at least one ethylene/acrylic acid copolymer, 15 to 35% by weight of at least one water-soluble homopolymer or copolymer, and 20 to 40% by weight of at least one powdered SAP having an average particle size of less than 80 microns.
The tackifying resins can be selected from the same group of tackifying resins discussed above. The water-dispersible EVA waxes are selected from polyethylene waxes based on an ethylene/vinyl acetate copolymer having a vinyl acetate content of up to 15% and molecular weights of between 500 and about 10,000. Flexibilizing ethylene copolymers, particularly ethylene/alkyl acrylate copolymers having an alkyl acrylate proportion of 15 to 40% by weight, are suitable as hydrophobic matrix components for binding the powdered superabsorbent polymer. Longer-chain alkyl acrylic esters are particularly suitable as comonomers in this respect, particularly the C4-C12 alkyl acrylates.
The water-soluble homopolymer or copolymer can include polyethylene glycol, ethylene oxide/propylene oxide copolymers (either as block copolymers or as random copolymers having a predominate proportion of ethylene oxide), polyvinyl methyl ether, polyvinyl pyrrolidone, polyvinyl alcohol, and copolymers of such monomers with other olefinically unsaturated monomers. In embodiments, these water-soluble polymers have molecular weights of between 1000 and 20,000, they may be liquid at room temperature, or they may be solid and waxy in cases where higher molecular weights are used. Suitable powdered superabsorbent polymers include those listed above.
In still another embodiment, the SA-SHM is comprised of 1% to 25% by weight of a block copolymer, 45% to 75% by weight of a powdered superabsorbent polymer, 15% to 40% by weight of a plasticizing oil, and optionally 1% to 5% by weight of a surfactant. Suitable block copolymers include linear and radial copolymer structures having the formula (A-B)x or A-B-A, where block A is a polyvinylarene block, block B is a poly(monoalkenyl) block, and x is an integer of at least 1. Suitable block A polyvinylarenes include, e.g., polystyrene, polyalpha-methylstyrene, polyvinyltoluene and combinations thereof. Suitable B blocks include, e.g., conjugated diene elastomers including, e.g., polybutadiene and polyisoprene, hydrogenated elastomers, ethylene/butylene (hydrogenated butadiene) and ethylene/propylene (hydrogenated isoprene), and combinations and mixtures thereof. Suitable powdered superabsorbent polymers include those listed above.
Suitable plasticizing oils include, e.g., hydrocarbon oils low in aromatic content, mineral oil. In a particular embodiment, the plasticizing oils are paraffinic or naphthenic. In some embodiments, the SA-SHM can also include tackifying agents, such as those listed above, up to 40% by weight.
In an embodiment, the SA-SHM includes at least one of sodium or potassium sodium acrylate or acrylamide copolymers, cross-linked carboxymethylcellulose, ethylene maleic anhydride copolymers, cross-linked polyethylene oxide, polyvinyl alcohol copolymers, or starch-grafted copolymers of polyacrylonitrile.
Referring to each of the above described SA-SHM compositions and to the use of SAP powders in general, in some embodiments, the average particle size of the SAP powders is between 1 micron and 100 microns. Broadly, in embodiments, the average particle size of the SAP powder is less than or equal to 80 microns. In other embodiments, the average particle size of the SAP powders is less than or equal to 50 microns. In still other embodiments, the average particle size of the SAP powders is less than or equal to 38 microns, and in yet other embodiments, the average particle size of the SAP powders is less than or equal to 25 microns. Further, in embodiments, the average particle size of the SAP powders is greater than 1 micron, and in other embodiments, the average particle size of the SAP powders is greater than 10 microns. Additionally, in embodiments, less than 50% of the SAP powder particles have a maximum outer dimension ≥50 microns. In still other embodiments, less than 10% of the SAP powder particles have a maximum outer dimension ≥38 microns, and in yet other embodiments, less than 10% of the SAP powder particles have a maximum outer dimension ≥25 microns. Further, in embodiments, the SAP powders have particles that are spherical in shape.
Tables 1-2, below, provide examples of the water absorption capabilities of four SA-SHM (referred to individually as “SHM1,” “SHM2,” “SHM3,” and “SHM4”) that can be used as the SAP component of the telecommunications enclosure according to exemplary embodiments. Certain SA-SHM capabilities are compared against a standard SAP powder (referred to as “SAP1”). In particular, SHM1 is commercially available as NW1117 from H.B. Fuller Company, Vadnais Heights, Minn. SHM2 is commercially available as NW1120B from H.B. Fuller Company, Vadnais Heights, Minn. SHM3 is commercially available as HM002 from Stewart Superabsorbents, Hickory, N.C. SHM4 is commercially available as HM008 from Stewart Superabsorbents, Hickory, N.C. SAP1 is a powderized sodium acrylate polymer having particles with average size of about 63 microns (commercially available from Stewart Superabsorbents, Hickory, N.C.). All experiments were performed at room temperature of about 22° C.
The data displayed in Table 1 demonstrates the water absorption capacities of SHM1 and SHM2 as compared to SAP1. In particular, particles of SAP1 and sections of SHM1 and SHM2 were placed in a beaker. The masses of each beaker before and after the addition of SAP1, SHM1, and SHM2 were determined so as to calculate the amount of each material added. A filter as then placed over the beaker, and the mass of the beaker/material/filter combination was determined. Water was added to the beaker, and the materials were given time to absorb as much water as they could. Any remaining, unabsorbed water was drained from the beaker, and the mass of the beaker/material/filter/absorbed water was determined. As can be seen from Table 1, SHM1 and SHM2 absorbed more water on a per gram basis than SAP1.
The data displayed in Table 2 demonstrates the water absorption capacities of SHM3 and SHM4 as compared to SAP1. In this experiment, the materials were placed on a glass slide. Each of the glass slides were weighed before and after the materials were placed thereon to determine the mass of each material deposited. Water was then added dropwise on the materials over a time up to 10 minutes and until it was visually observed that the material was saturated and the extra water dripped off. The glass slides with gelled material were then weighed to determine the amount of water absorbed. As can be seen in Table 2, SHM3 and SHM4 performed as well or better than SAP1 in terms of water absorbed on a per gram basis.
Advantageously, embodiments of the telecommunications enclosures using SAP for sealing enhance effectiveness of telecommunications enclosures used to protect optical fiber splices or copper connections from the environment. Indeed, the SAP can be used as the primary sealing mechanism for the enclosure or as a secondary sealing mechanism to absorb water that leaks past the primary gasket.
Further, while telecommunications enclosures were described herein by way of illustration, in other embodiments, the enclosure can be used to protect optical components, opto-electrical components, electrical components, or wireless components. For example, optical components include the splice region between the optical fibers of two cables that are spliced within the enclosure. Other optical components include connectors, ports, repeaters, switches, and the like. In exemplary embodiments, opto-electrical components also include connectors, ports, repeaters, switches, and the like that utilize both electrical and optical signals or that convert electrical signals to optical signals and vice versa. Further, in exemplary embodiments, wireless components include routers, terminals, receivers, antennas, and the like. The enclosure for each of these applications is sized to accommodate the particular components placed therein, and the combination of SAP tapes, yarns, fabrics, powders, or gaskets described herein is able to prevent the ingress of water into the internal cavities of such enclosures during the operational lifetime of these enclosures.
Also described herein is a method of manufacturing a telecommunications equipment enclosure using SAP. The method includes forming a first portion, such as the lid 14, having a first sealing surface, such as the first peripheral surface 17. The method also includes forming a second portion, such as the bin portion 12, having a second sealing surface, such as the second peripheral surface 18, wherein the first portion and the second portion define an internal cavity 20 when the first sealing surface contacts the second sealing surface and the first portion and the second portion are in a closed configuration. The method also includes placing a first gasket, such as the peripheral gasket 28, on either the first sealing surface or the second sealing surface. The method also includes placing a superabsorbent polymer (SAP) on at least one of the first portion and the second portion for restricting ingress of water into the internal cavity 20 when the first portion and the second portion are in the closed configuration.
Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that any particular order be interred. In addition, as used herein, the article “a” is intended to include one or more than one component or element, and is not intended to be construed as meaning only one.
It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the disclosed embodiments. Since modifications, combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the embodiments may occur to persons skilled in the art, the disclosed embodiments should be construed to include everything within the scope of the appended claims and their equivalents.
