Electrical cable accessory system and method including the electrical cable accessory system

Abstract

The present disclosure describes an electric cable accessory system for covering an electric cable and / or a cable connection. The electric cable accessory system includes a pre-expanded cable accessory unit and a time-temperature indicator associated with the pre-expanded cable accessory unit. The pre-expanded cable accessory unit includes a pre-expanded cable accessory formed from an elastomeric material and a removable holdout mounted within the elastomeric cable accessory. The holdout operates to maintain the elastomeric cable accessory in an expanded state and to allow the elastomeric cable accessory to elastically contract when the holdout is removed from the elastomeric cable accessory. The time-temperature indicator is configured to undergo a visible change in appearance in response to cumulative heat exposure, alerting an observer when the elastomeric material of the pre-expanded elastomeric cable accessory unit has experienced a threshold cumulative heat exposure. Methods including the electric cable accessory system are also described herein.

Description

Technical Field

[0001] The present invention relates to electrical cables and connections, and more particularly to protective pre-expanded cable accessory units for protecting electrical cables and electrical connections.

Background Art

[0002] Elastomeric covers and cover assemblies are commonly used to protect or shield power cables (e.g., low voltage cables up to about 1000V and medium voltage cables up to about 46kV) and connections (e.g., splices or terminations). Such an elastomeric cover may be a room temperature shrinkable sleeve provided in the form of a pre-expanded cover unit, which includes a sleeve and a holdout, with the sleeve pre-mounted on the holdout in an expanded state. Providing the elastomeric cover in this form to an end user (e.g., a customer or installer) can facilitate and ensure the installation of the cover on the cable or connection. The pre-expanded cover unit can be stored by the manufacturer or customer for a long period of time.

Summary of the Invention

Means for Solving the Problems

[0003] Embodiments of the present invention relate to an electrical cable accessory system that covers an electrical cable and / or a cable connection. The electrical cable accessory system includes a pre-expanded cable accessory unit and a time-temperature indicator associated with the pre-expanded cable accessory unit. The pre-expanded cable accessory unit includes a pre-expanded cable accessory formed from an elastomeric material and a removable holdout mounted within the elastomeric cable accessory, the holdout operating to maintain the elastomeric cable accessory in an expanded state and to enable the elastomeric cable accessory to elastically contract when the holdout is removed from the elastomeric cable accessory. The time-temperature indicator is configured to visibly change appearance in response to cumulative heat exposure and to notify an observer when the elastomeric material of the pre-expanded elastomeric cable accessory unit has received a threshold cumulative heat exposure.

[0004] Further embodiments of the present invention relate to a method for monitoring cumulative heat exposure to a pre-expanded elastomeric cable accessory unit that covers an electrical cable and / or a cable connection. The method includes providing an electrical cable accessory system that includes a pre-expanded cable accessory unit and a time-temperature indicator associated with the pre-expanded cable accessory unit. The pre-expanded cable accessory unit includes a pre-expanded cable accessory formed from an elastomeric material and a removable holdout mounted within the elastomeric cable accessory, the holdout operating to maintain the elastomeric cable accessory in an expanded state and to enable the elastomeric cable accessory to elastically contract when the holdout is removed from the elastomeric cable accessory. The time-temperature indicator is configured such that its appearance visibly changes in response to cumulative heat exposure. The method further includes monitoring the visible change in the appearance of the time-temperature indicator to determine whether the elastomeric material of a pre-expanded elastomer cable accessory unit has received a threshold cumulative heat exposure.

[0005] A further embodiment of the present invention relates to a method of forming an electrical cable accessory system for monitoring cumulative heat exposure to a pre-expanded elastomer cable accessory unit. The method includes providing an electrical cable accessory system comprising a pre-expanded cable accessory unit and a time-temperature indicator associated with the pre-expanded cable accessory unit. The pre-expanded cable accessory unit includes a pre-expanded cable accessory formed from an elastomeric material and a removable holdout mounted within the elastomeric cable accessory, the holdout maintaining the elastomeric cable accessory in an expanded state and operative to allow the elastomeric cable accessory to elastically contract when the holdout is removed from the elastomeric cable accessory. The time-temperature indicator is configured such that its appearance visibly changes in response to cumulative heat exposure. The method further includes securing the time-temperature indicator to the pre-expanded cable accessory unit or to packaging that houses the pre-expanded cable accessory unit.

[0006] Hereinafter, the present invention will be described by way of example with reference to the accompanying drawings.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 5

Figure 6A-6C

Figure 7

Figure 8A

Figure 8B

Figure 9A

Figure 9B

Figure 10

Figure 11

DETAILED DESCRIPTION OF THE INVENTION

[0008] The present invention will now be described more fully with reference to the accompanying drawings, which illustrate exemplary embodiments of the invention. In the drawings, the relative sizes of regions or structures may be exaggerated for clarity. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the disclosure to those skilled in the art.

[0009] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms defined in commonly used dictionaries should be interpreted as having a meaning that coincides with their meaning in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0010] Embodiments of the present invention relate to an electrical cable accessory system comprising a pre-expanded cable accessory unit. The pre-expanded cable accessory unit comprises an elastomeric cable accessory and a holdout. The electrical cable accessory system can further comprise a packaging for housing or holding the pre-expanded cable accessory unit. The cable accessory is attached to the holdout such that the holdout holds the cable accessory in an elastically expanded (e.g., radially expanded) state. In use, the cable accessory is placed from the holdout onto a cable or cable connection such that the cable accessory can elastically contract radially around the cable or cable connection.

[0011] The electrical cable accessory system further comprises a time-temperature indicator associated with the pre-expanded cable accessory unit. In some embodiments, the time-temperature indicator is attached to the packaging associated with the cable accessory. In some embodiments, the time-temperature indicator is attached to the cable accessory. In some embodiments, the time-temperature indicator is attached to a portion of the pre-expanded cable accessory unit other than the cable accessory. The time-temperature indicator is configured to optically, visually, or visibly change appearance in response to cumulative heat exposure. In use, the user can refer to the time-temperature indicator to determine whether an expanded cable accessory that has received the same or substantially the same cumulative heat exposure as the time-temperature indicator has reached, received, or been exposed to a specified threshold cumulative heat exposure.

[0012] The elastomeric cable accessory can be any suitable type of elastomeric cable accessory. In some embodiments, the elastomeric cable accessory is an elastomeric tubular cover sleeve. In some embodiments, the elastomeric cable accessory can be a splice, a termination cover, an elbow, a re-jacket sleeve, a breakout sleeve, a cable adapter, or other cable accessory.

[0013] The pre-expanded cable accessory unit can include other components attached to the holdout in addition to the pre-expanded elastomeric cable accessory. In some embodiments, the pre-expanded cable accessory unit further includes a second elastomeric cable accessory attached to the holdout, and the holdout is configured to hold the second elastomeric cable accessory in an elastically expanded (e.g., radially expanded) state. For example, the pre-expanded cable accessory unit can include a pre-expanded splice attached to (and expanded and held by) the holdout as a first expanded elastomeric cable accessory, and a re-jacket sleeve attached to (and expanded and held by) the holdout as a second expanded elastomeric cable accessory. Additional non-elastomeric components or components that do not expand elastically, such as a metal shield mesh sleeve, can be attached to the holdout.

[0014] In some embodiments, the cover sleeve is a cable accessory made of a room-temperature shrinkable elastomer (e.g., a room-temperature shrinkable cover sleeve). As used herein, "room-temperature shrinkable" or "room-temperature shrinkable cover" means that the cover or component can shrink or contract around a substrate (e.g., a cable) without the need to apply heat. As used herein, "room-temperature applicable" or "room-temperature applicable cover" means that the cover or component can be assembled or installed around a substrate (e.g., a cable) without the need to apply heat during installation.

[0015] The electrical cable accessory system of the present invention can address problems and concerns related to the aging and deterioration of a pre-expanded cable accessory made of a pre-expanded elastomer provided in a pre-expanded cable accessory unit. The room-temperature shrinkable cable accessory relies on a stretched elastomer material that relaxes based on (in response to) time and temperature exposure. This compression can be important or essential to ensure proper sealing and / or dielectric strength.

[0016] When the room-temperature shrinkable cable accessory is exposed to a cumulative heat amount (i.e., thermal energy) that exceeds a threshold cumulative heat amount, it can no longer maintain sufficient elasticity to apply a desired minimum amount of compressive pressure to a substrate (e.g., a cable). As used herein, "excessive heat exposure" means that the cable accessory made of an elastomer has been exposed to a cumulative heat amount that exceeds a predetermined threshold cumulative heat amount.

[0017] For this reason, such products are generally provided with an expiration date to provide users or customers with a rough estimate of the effective storage life of a room temperature shrinkable cable accessory. Since manufacturing cannot predict the actual handling and storage conditions of the product, the expiration date may be based on a conservative assumption. As a result, a pre-expanded cable accessory unit may reach its expiration date before its cover sleeve actually relaxes or thermally ages beyond its effective limit. A time-temperature indicator for an electrical cable accessory system addresses this problem by providing a more accurate individual assessment, indication, or measurement of the thermal aging of the expanded cable accessory of the associated pre-expanded cable accessory unit. Accordingly, the time-temperature indicator can function as a storage life indicator for the cable accessory and can form a storage life indicator system (or part of a storage life indicator system) for the electrical cable accessory system.

[0018] Hereinafter, embodiments of the present invention will be described in more detail with reference to FIGS. 1 to 11.

[0019] In FIG. 1, an electrical cable accessory system according to some embodiments of the present invention is generally indicated at 5. The electrical cable accessory system 5 includes a time-temperature indicator 10. The time-temperature indicator 10 may also be referred to herein as a "storage life indicator". The electrical cable accessory system 5 also includes a pre-expanded cable accessory unit 50. In some embodiments, the electrical cable accessory system 5 may optionally include packaging 60.

[0020] The pre-expanded cable accessory unit 50 includes a cable accessory 52 made of pre-expanded elastomer and a hold-out device 54. As shown in FIG. 1, in some embodiments, the cable accessory 50 made of pre-expanded elastomer may be a cover assembly or a cover sleeve 52 held in an expanded state or an expanded position on the hold-out 54. The cable accessory 52 made of pre-expanded elastomer may be attached to the hold-out 54 to form a single or integral structure.

[0021] The hold-out 54 maintains the cable accessory 52 made of pre-expanded elastomer in an elastically expanded state (for example, when the cable accessory 52 is relaxed, the outer diameter of the hold-out 54 is larger than the inner diameter of the cable accessory 52). The hold-out 54 is configured to hold the cable accessory 52 in the expanded position until it is removed from the cable accessory unit 50. The pre-expanded cable accessory unit 50 can be placed and attached in a retracted state or a retracted position on an intended substrate (such as a cable). According to some embodiments, the cable accessory 52 expands by about 200 to 400 percent in the expanded state with a relaxed diameter (i.e., not on the substrate). As a result, the cable accessory 52 of the pre-expanded cable accessory unit 50 applies a radial compressive pressure or compressive load to the hold-out 54. According to some embodiments, the cable accessory 52 made of pre-expanded elastomer may be a room temperature shrinkable cover sleeve.

[0022] In some embodiments, the holdout 54 is a decomposable or foldable rigid tube. According to some embodiments, the holdout 54 is generally what is called a helical holdout or core. In some embodiments, the holdout 54 is a non-helical core that can be removable and / or retractable. The holdout 54 can include a tubular cylindrical member or body. In some embodiments, the holdout 54 includes a continuous flexible ribbon or strip that is helically wound to form a series of looped strip portions. The strip portions are releasably or removably joined to each adjacent strip portion along its edge, thereby forming or configuring a holdout body in the form of a rigid tubular cylinder.

[0023] The holdout 54 can be formed from any suitable material. According to some embodiments, the holdout 54 is formed from a semi-rigid polymer material. According to some embodiments, the holdout 54 is formed from high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene, ABS, or PVC. According to some embodiments, the pre-expanded cable accessory 52 is formed from a dielectric material or an electrical insulating material. According to some embodiments, the cable accessory 52 is formed from an elastically expandable material. According to some embodiments, the cable accessory 52 is formed from an elastomer material. According to some embodiments, the cable accessory 52 is formed from liquid silicone rubber (LSR). Other suitable materials include EPDM or ethylene propylene rubber (EPR).

[0024] When the holdout 54 is withdrawn (released), the cable accessory 52 contracts towards the intended substrate (i.e., the cable). The relaxed inner diameter of the cable accessory 52 is smaller than at least the outer diameter of the jacket and the outer diameter of the semiconductor layer of the cable. Thus, the cable accessory 52 applies a permanent radially inward compressive force or clamping force or pressure (due to elastic tension) to the cable. Thereby, the cable accessory 52 can provide a liquid-tight seal at the interface between the cable and the cable accessory 52. This seal can protect the cable (and the connection) from the ingress of ambient moisture. According to some embodiments, the relaxed inner diameter of the cable accessory 52 is about 20 - 40 percent smaller than the smallest diameter cable for which the cable accessory 52 is intended to be installed.

[0025] As shown in FIG. 1, the illustrated pre-expanded cable accessory unit 50 includes only a single pre-expanded elastomeric cable accessory 52, but as described below, it is contemplated that the pre-expanded cable accessory unit 50 can include two or more pre-expanded elastomeric cable accessories 52 (e.g., each elastically expanded and attached to a holdout 54) and other components (e.g., a metal mesh shield) forming the pre-expanded cable accessory unit 50 (see, e.g., FIGS. 9A, 9B).

[0026] The pre-expanded cable accessory unit 50 may be disposed in a packaging 60 and is intended to remain within the packaging 60 until the pre-expanded cable accessory unit 50 is used or discarded. In FIGS. 1 and 3A, 3B (and FIGS. 8A, 8B), the packaging 60 is shown as a box (e.g., a cardboard box), but other forms of packaging may be used instead. For example, the packaging 60 may be a bag, shrink wrap, or any other suitable packaging.

[0027] In some embodiments, the time - temperature indicator 10 is affixed to the packaging 60. For example, as shown in FIGS. 1 and 3A, 3B (and FIGS. 7A, 7B), the time - temperature indicator 10 is mounted on the packaging 60. In some embodiments, the time - temperature indicator 10 is affixed to the packaging 60 in a position visible to the user without opening the packaging 60 or accessing the pre - expanded cable accessory unit 50.

[0028] FIGS. 1 - 8B show exemplary time - temperature indicators 10, 100 that may form part of the electrical cable accessory systems 5, 500 of the present invention. The time - temperature indicators 10, 100 are configured to monitor, for example, during transportation and / or storage of the electrical cable accessory systems 5, 500, the cumulative heat exposure to the indicators 10, 100 and thereby the cumulative heat exposure to the pre - expanded cable accessory unit 50 (and the pre - expanded elastomeric cable accessory 52) maintained in the packaging 60 containing the indicators 10, 100. That is, the time - temperature indicators 10, 100 are arranged and configured to be exposed to a cumulative heat amount that is substantially the same as or proportional to the cumulative heat amount to which the elastomeric cable accessory 52 is exposed. The time - temperature indicators 10, 100 are configured to notify an observer when a predetermined or predicted cumulative heat exposure value is reached that correlates or may correlate with a predetermined or predicted decrease (or degradation) in the elastomeric properties of the pre - expanded elastomeric cable accessory 52. In some embodiments, the predicted rate of occurrence of the elastomeric property degradation and the threshold cumulative heat exposure are determined or modeled using experimentally obtained data and / or using a theoretical or analytical model or equation such as the Arrhenius equation.

[0029] As will be described in further detail below, in some embodiments, the signal may be a color change, e.g., darkening of the indicator region 20 of the time-temperature indicator 10, and may be produced by a heat-sensitive agent (i.e., a heat-responsive agent) such as a diacetylene compound, or by another technique that incorporates heat exposure over time. In some embodiments, the time-temperature indicator 10 is a thermochromic indicator. Examples of thermochromic indicators that may be used in connection with the present invention are described in Prusik et al. U.S. Patent No. 10,514,340, the disclosure of which is hereby incorporated by reference in its entirety. In some embodiments, the signal may be a color change that moves along the indicator region 200 of the time-temperature indicator 100, and may be produced by a viscous liquid that moves along a moving medium, or by another technique that incorporates heat exposure over time. In some embodiments, the time-temperature indicator 100 is a liquid movement (e.g., dye diffusion) indicator. Examples of liquid movement indicators that may be used in connection with the present invention are described in Isbitsky et al. U.S. Patent No. 7,232,253, the disclosure of which is hereby incorporated by reference in its entirety.

[0030] As used herein, the term "color" includes colorless visual appearances such as black, gray, and white, and colored visual appearances having primary colors, secondary colors, and / or other hues including, but not limited to, red, yellow, green, blue, purple, orange, brown, and other colors. The term "color change" and its grammatical variations are used to refer to a change in hue, purity, or brightness (or darkness), or other change in visual appearance.

[0031] Referring to FIGS. 1-4B, the time-temperature indicator is a thermochromic time-temperature indicator 10. As shown in FIG. 2 (see also FIGS. 3A and 3B), in some embodiments, the time-temperature indicator 10 can include a visible indicator region 20 for viewing a visible change in appearance corresponding to the cumulative heat exposure. In some embodiments, the visible change in appearance can include darkening of the indicator region 20. In some embodiments, the indicator 10 may also include a colored reference region 24 adjacent to the indicator region 20. As shown in FIG. 2, in some embodiments, the reference region 24 can surround the indicator region 20.

[0032] In some embodiments, the indicator region 20 of the time-temperature indicator 10 can exhibit a distinct color change after activation of the color-changing composition that provides good contrast with the appearance of the indicator 10 (i.e., the reference region 24) before activation of the color-changing composition, indicating a clear irreversible signal suggesting that a harmful heat exposure may have occurred, for example, significant darkening of the indicator region 20.

[0033] The reference region 24 can be colored to show the end point appearance of the indicator region 20. For example, in some embodiments, the indicator region 20 initially has an appearance that is lighter than the appearance of the reference region 24, and the indicator region 20 is configured to darken as the indicator 10 (and associated pre-expanded elastomer cable accessory 52) is exposed to heat over time (FIG. 2). In some embodiments, the time-temperature indicator 10 can be used to determine whether the indicator 10 has received a threshold cumulative heat exposure. In some embodiments, the appearance at the end point (i.e., the threshold cumulative heat exposure) may be a visible change in appearance such that the appearance of the indicator region 20 is the same as or darker than the appearance of the reference region 24, thereby indicating a possible state of the associated pre-expanded elastomer cable accessory unit 50, e.g., that the pre-expanded elastomer cable accessory 52 of the pre-expanded cable accessory unit 50 has lost efficacy or quality and should not be used (i.e., relaxation of the elastomer material forming the pre-expanded elastomer cable accessory 52 and / or a portion thereof).

[0034] The time-temperature indicator 10, the indicator region 20, and the reference region 24 can each have any desired shape. Independently considered, the shape can be circular, square, rectangular, triangular, hexagonal, polygonal, elongated, circular, oval, elliptical, flake-shaped, another regular shape, an irregular shape, a shape representing a recognizable image such as a check mark, or another suitable shape. As shown in FIG. 1, by way of example, the indicator 10 is circular, the reference region 24 occupies a smaller circle, and the indicator region 20 is configured as a square within the circle of the reference region 24. As shown in FIGS. 2 and 3A, 3B, by way of example, the indicator 10, the reference region 24, and the indicator region 20 are each circular. In some embodiments, the reference region 24 and the indicator region 20 can each be rectangular, such as the reference region 240 and the indicator region 200 of the time-temperature indicator 100 shown in FIGS. 5-8B.

[0035] The size of the time-temperature indicator 10 can vary according to the intended application or for other purposes. In some embodiments, the indicator 10 can have a maximum lateral dimension of about 5 mm to about 30 mm, e.g., about 10 mm to about 15 mm. In such embodiments, the indicator region 20 can have a maximum lateral dimension of about 1 mm to about 10 mm, e.g., about 2 mm to about 6 mm.

[0036] In some embodiments of the present invention, the color change composition within the indicator region 20 of the time-temperature indicator 10 may be, or may include, a heat-sensitive agent (i.e., a heat-responsive agent). The heat-sensitive agent can react to heat to change its appearance and can function as an integrated heat indicator related to the rate of decrease in the elasticity of the corresponding pre-expanded elastomeric cable accessory 52. For example, in some embodiments, the heat-sensitive agent can darken upon continuous heat exposure (see, e.g., FIGS. 2 and 3B), and the degree of darkening can be a measure of the integrated heat exposure to the electrical cable accessory system 5. Alternatively, the heat-sensitive agent can exhibit another change in appearance, such as lightening, a change in hue, or another visually readable indication. The heat-sensitive agent can include one or more heat-sensitive compounds, some of which are described elsewhere in this specification.

[0037] The indicator region 20 of the time-temperature indicator 10 can be manufactured by applying an appropriate indicator ink containing a heat-sensitive agent to a substrate and then drying the indicator ink on the substrate. The indicator region 20 can include the dried ink residue and the substrate that supports the ink residue. The indicator ink can include a liquid vehicle, a film-forming agent dissolved in the liquid vehicle, an insoluble heat-sensitive agent dispersed in the liquid vehicle, and various optional components, such as one or more dispersants, light stabilizers, colorants, preservatives, fragrances, or other additives. Examples of suitable liquid vehicles are organic solvents such as isopropanol or ethyl 3-ethoxypropionate. An example of a suitable film-forming agent is nitrocellulose.

[0038] Some useful heat-sensitive agents can provide an irreversible indication of cumulative temperature exposure over time and can provide a record of long-term heat exposure. The cumulative heat reaction of the heat-sensitive agent can be such that the heat-sensitive agent can monitor heat exposure as an integral of temperature over time. Further, the heat-sensitive agent can be heat-sensitive and can have useful indicator reactivity at ambient temperatures that the monitored host product may encounter, such as temperatures from about 0°C to about 60°C.

[0039] The heat-sensitive agent may contain any of various chemical components or may be composed of any of various chemical components. An example of a useful heat-sensitive agent includes one or more heat-sensitive diacetylene compounds, for example, an individual diacetylene compound or a co-crystallized mixture of two diacetylene compounds.

[0040] One or more diacetylene compounds can polymerize to provide a color change or another optically readable indication. Diacetylene compounds useful in the practice of exemplary embodiments of the present invention include polymerizable diacetylene compounds containing at least two conjugated acetylene groups, i.e., groups having the chemical formula -C≡C-. Some exemplary polymerizable diacetylene compounds that can be used include substituted 2,4-hexadiyne-1,6-bis(alkylurea) compounds in which the alkyl group has 1 to 20 carbon atoms, the above diacetylene bis(alkylurea) compounds in which the alkyl substituent is linear, and co-crystallized mixtures of any two or more of the above bis(alkylurea) compounds. The two alkyl groups in any of the above diacetylene bis(alkylurea) compounds can be the same, and the bis(alkylurea) compound can be symmetrically substituted. Some specific examples of the above diacetylene bis(alkylurea) compounds include ethyl, propyl, butyl, octyl, dodecyl, and octyldecyl substituted 2,4-hexadiyne-1,6-bis(alkylurea) compounds, linear isomers of these compounds, and co-crystallized mixtures of two or more of the linear isomers.

[0041] As a heat-sensitive agent for the cumulative exposure indicator component of the time-temperature indicator 10 of the present invention (e.g., the color-changing composition of the indicator region 20), or other chemistries and techniques that can be used in heat-sensitive agents, include heat-sensitive dyes that can be activated or inactivated by exposure to ultraviolet irradiation to provide or remove color, dyes that are induced to exhibit or change color by a pH change, reversible photochromic compounds, such as spiro aromatic compounds, that undergo photoinduced coloring by light or ultraviolet irradiation and then undergo time- and temperature-dependent decolorization, and enzyme-based sensors. Other techniques further include enzyme-based techniques, where the blister pack contains two mixed components, and ultimately, the mixed components change color over time / temperature and also change mechanical functions (e.g., diffusion type) and chemical functions (e.g., solid-state polymerization). Additional suitable techniques for the indicator region 20 that can be used in practicing embodiments of the present invention will be known or apparent to those skilled in the art in light of the present disclosure, or may become known or apparent in the future.

[0042] As shown in FIG. 2 (see also FIGS. 3A, 3B, and 5-7B), in some embodiments, the reference region 24 causes a visible change in appearance that indicates the endpoint (or threshold cumulative heat exposure) of the corresponding pre-expanded elastomeric cable accessory 52 of the electrical connection cover system 5 after a predetermined cumulative heat exposure has occurred, having an appearance similar to that of the indicator region 20, thereby assisting an observer or observation device in determining the state of the color-changing composition within the indicator region 20. In some embodiments, the indicator region 20 can include an indication that shows an observer how much shelf life remains. For example, as shown in FIG. 7, in some embodiments, the indicator region 200 includes an indication 150 that reflects the percentage of remaining shelf life.

[0043] In some embodiments, the threshold cumulative heat exposure for the pre-expanded cable accessory system 50 (i.e., the pre-expanded elastomer cable accessory 52) can be about 40 °C (104 °F) over a period of about two years. In some embodiments, the threshold cumulative heat exposure of the pre-expanded cable accessory system 50 (i.e., the pre-expanded elastomer cable accessory 52) can be about 40 °C (104 °F) over a period of about 730 days. In some embodiments, the threshold cumulative heat exposure for the pre-expanded cable accessory system 50 (i.e., the pre-expanded elastomer cable accessory 52) can be about 60 °C (140 °F) over a period of about 60 days. The threshold cumulative heat exposure varies based on the materials used and the tension setting requirements of the pre-expanded cable accessory system 50 (i.e., the pre-expanded elastomer cable accessory 52).

[0044] Figures 3A, 3B (and Figure 1) show a time-temperature indicator 10 attached to a packaging 60 that houses the pre-expanded cable accessory unit 50. Figure 3A shows the unit of the electrical cable accessory system 5 before excessive heat exposure. The pre-expanded cable accessory unit 50 is stored within the packaging 60 with the time-temperature indicator 10 attached to the outer surface of the packaging 60. As shown in Figure 3A, the indicator region 20 of the time-temperature indicator 10 is lighter in color than the reference region 24, indicating to an observer that the electrical cable accessory system 5 has not yet received the threshold cumulative heat exposure. Thus, the associated pre-expanded cable accessory unit 50 is still suitable for its intended use.

[0045] Figure 3B shows the electrical cable accessory system 5 after excessive heat exposure. As shown in Figure 3B, the indicator region 20 of the time-temperature indicator 10 is darker in color than the reference region 24 (i.e., a visible change in appearance has occurred compared to the indicator region 20 of the electrical cable accessory system 5 in Figure 3A), indicating to the observer that the electrical cable accessory system 5 (and the associated pre-expanded cable accessory unit 50 housed within the packaging 60) has received a threshold cumulative heat exposure. Thus, it indicates to the observer that the pre-expanded cable accessory unit 50 is no longer suitable for its intended use.

[0046] Referring to FIGS. 5-9B, the time-temperature indicator is a liquid movement (e.g., dye diffusion) indicator 100. Similar to the indicator 10 described herein, in some embodiments, the time-temperature indicator 100 can include a visible indicator region 200 for viewing a visible change in appearance corresponding to cumulative heat exposure. As shown in FIGS. 5-7, in some embodiments, the visible change in appearance includes a color change that moves along the indicator region 200. As shown in FIGS. 6A-6C, in some embodiments, the cumulative exposure indicator component of the time-temperature indicator 100 can be generated by a viscous liquid 120 that moves along a moving medium 110 within the indicator region 200. In some embodiments, as the viscous liquid 120 moves along the moving medium 110 (e.g., the tip 120a of the color change), a color change occurs, indicating the time-dependent heat exposure to the time-temperature indicator 100. The rate of progression at which the viscous liquid 120 moves along the moving medium 110 changes with temperature (and indirectly with heat exposure). For example, the viscous liquid 120 moves faster (i.e., is carried) at higher temperatures than at lower temperatures. The temperature indicator 100 tracks the temperature (i.e., heat) exposure that changes over time to determine the threshold cumulative heat exposure to the indicator 100 (and the corresponding pre-expanded elastomeric cable accessory 52 of the electrical connection cover system 500).

[0047] In other embodiments, the time-temperature indicator 100 can track excessive heat exposure, i.e., when the temperature exceeds a predetermined threshold value (e.g., a critical temperature), which induces a visible change (e.g., movement of the viscous liquid 120 along the mobile medium 110) indicating that the indicator 100 (and the corresponding pre-expanded elastomer-made cable accessory 52 of the electrical connection cover system 500) has been exposed to or subjected to the critical temperature.

[0048] In some embodiments, the time-temperature indicator 100 includes a first reservoir 125 that houses the viscous liquid 120. In some embodiments, the time-temperature indicator 100 can be activated by a user depressing the first reservoir 125 to send the liquid 120 from the first reservoir 125 through the inlet 125a to a second reservoir 130 that houses the mobile medium 110. After activation, the liquid 120 travels from the first reservoir 125 to the second reservoir 130 and moves along the length of the mobile medium 110 over time, i.e., in the direction of the arrow (FIG. 5). FIG. 6A shows the indicator 100 before activation and heat exposure, FIG. 6B shows the indicator 100 after activation and during heat exposure, and FIG. 6C shows the indicator 100 after the indicator 100 has been subjected to a predetermined threshold cumulative heat exposure (i.e., after excessive heat exposure).

[0049] In some embodiments, the mobile medium 110 can be a porous material such as a porous polymer, e.g., a polyolefin plastic (mainly containing a silica filler) such as Teslin® (PPG Industries Inc., Pennsylvania, USA), or a polyethylene containing a silica filler such as Artisyn™ (Daramic Inc., Owensboro, Kentucky, USA). The liquid 120 used can be any viscous liquid containing a suitable (e.g., red) coloring, e.g., a cooking oil such as corn oil containing an oil-soluble red dye such as Oil Red EGN (Sigma-Aldrich, St. Louis, Missouri, USA). See, e.g., Isbitsky et al., U.S. Patent No. 7,232,253 as well.

[0050] As shown in FIG. 7, in some embodiments, the reference region 240 can surround the indicator region 200 and can include, for example, a display 150 corresponding to the remaining shelf life based on the movement of the color change along the indicator region 200 (i.e., the movement of the viscous liquid 120 along the moving medium 110). When the color of substantially the entire indicator region 200 changes (or when the color change moves to each display 150, i.e., 0% of the remaining shelf life), the corresponding pre-expanded elastomeric cable accessory 52 of the electrical connection cover system 5, 500 has reached the end of its shelf life (or indicates to the observer that it has received a threshold cumulative heat exposure (see also FIGS. 8A and 8B for example).

[0051] FIGS. 8A and 8B show a time-temperature indicator 100 attached to a packaging 60 that houses a pre-expanded cable accessory unit 50. FIG. 8A shows a unit of the electrical cable accessory system 500 before excessive heat exposure. The pre-expanded cable accessory unit 50 is stored within a packaging 60 with the time-temperature indicator 100 attached to the outer surface of the packaging 60. As shown in FIG. 8A, there is no visible color change in the indicator region 200 of the time-temperature indicator 100, indicating to the observer that the electrical cable accessory system 500 has not received a threshold cumulative heat exposure. Thus, the associated pre-expanded cable accessory unit 50 is still suitable for its intended use.

[0052] FIG. 8B shows an electrical cable accessory system 500 that has received a threshold cumulative heat exposure (i.e., after excessive heat exposure). As shown in FIG. 8B, the colored viscous liquid 120 has moved along the entire indicator region 200 of the time-temperature indicator 100 (i.e., the mobile medium 110) (i.e., there has been a change in the visual appearance compared to the indicator region 200 of the electrical cable accessory system 500 in FIG. 8A), indicating to an observer that the electrical cable accessory system 500 (and the associated pre-expanded cable accessory unit 50 housed within the packaging 60) has received a threshold cumulative heat exposure (i.e., the remaining shelf life is 0%). Thus, it indicates to the observer that the pre-expanded cable accessory unit 50 is no longer suitable for its intended use.

[0053] Various configurations of the time-temperature indicators 10, 100 are possible. For example, in some embodiments, the indicators 10, 100 may be embodied as an adhesive configuration and may be suitable for direct attachment to a mass-produced host product (e.g., the pre-expanded cable accessory unit 50) (see, e.g., FIGS. 4A, 4B), or may be attached to the packaging 60 (or container) of the host product (see, e.g., FIGS. 1, 3A, 3B, and FIGS. 8A, 8B). The time-temperature indicators 10, 100 may be configured to conform to the host product or the packaging of the host product. The surface of the time-temperature indicators 10, 100 may be flat so as to conform to a flat surface of the host product (or the package containing the host product).

[0054] Alternatively, the surfaces of the time-temperature indicators 10, 100 may be curved in one or two dimensions so as to conform to the curved surface of the host product (or the package containing the host product), such as the curved surface of the holdout 54 (see, e.g., FIG. 4A) or the curved surface of the pre-expanded elastomeric cable accessory 52 (see, e.g., FIG. 4B). Attachment by adhesion is an example of a different way of associating the indicators 10, 100 with the host product so as to monitor the host product for cumulative heat exposure. Possible different attachment methods include, for example, adhesion, tying (ying), looping, stapling to the host product directly, or to the package containing the host product, or to a package, ball box, box, or other container having some host product items inside. Furthermore, the time-temperature indicators 10, 100 embodied in a label or tag can be inserted into the package of the host product, a ball box, or other container for one or more host product items.

[0055] In some embodiments, the electrical cable accessory system 5, 500 of the present invention can comprise a pre-expanded cable accessory unit 50 having two or more pre-expanded elastomeric cable accessories 52. For example, as shown in FIGS. 9A and 9B, the pre-expanded cable accessory unit 50' can comprise two pre-expanded elastomeric cable accessories 52', 56'. In some embodiments, the elastomeric cable accessories 52', 56' may be formed from the same material. In this way, the elastomeric properties of the cable accessories 52', 56' degrade at a similar rate. Accordingly, the time-temperature indicators 10, 100 of the electrical cable accessory system 5, 500 indicate to an observer when both pre-expanded elastomeric elements (i.e., cable accessories 52', 56') included in the cable accessory unit 50' have received a threshold cumulative heat exposure.

[0056] This is the same when, for example, the pre-expanded cable accessory unit 50' has three or more pre-expanded elastomeric cable accessories 52', 56', and each of the elastomeric cable accessories is formed from the same material. However, in some embodiments, the pre-expanded elastomeric cable accessories 52', 56' may be formed from different elastomeric materials (e.g., EPDM and silicone) that can degrade at different rates when exposed to heat. In those embodiments, the time-temperature indicators 10, 100 are configured to indicate to an observer when a pre-expanded elastomeric cable accessory 52', 56' formed from an elastomeric material that degrades at a faster rate compared to the other pre-expanded elastomeric cable accessories 52', 56' of the cable accessory unit 50' has received a threshold cumulative heat exposure. In other words, the time-temperature indicators 10, 100 inform of the cumulative heat exposure (and the threshold cumulative heat exposure) of the weakest or most susceptible pre-expanded elastomeric cable accessories 52', 56' of the pre-expanded cable accessory units 50, 50'.

[0057] As described above, the electrical cable accessory system 5, 500 of the present invention comprises a pre-expanded cable accessory unit 50, time-temperature indicators 10, 100, and optionally, a packaging 60 for the pre-expanded cable accessory unit 50. With the electrical cable accessory system 5, 500, a user can monitor the cumulative heat exposure to the pre-expanded cable accessory units 50, 50' and their elements (i.e., the pre-expanded elastomeric cable accessories 52, 52', 56') and / or the packaging 60 that houses the pre-expanded cable accessory units 50, 50'.

[0058] The pre-expanded elastomer cable accessories 52, 52', 56' described herein may be any suitable type of elastomer cable accessory system 5, 500 (and pre-expanded cable accessory unit 50, 50'). In some embodiments, the pre-expanded elastomer cable accessories 52, 52', 56' are elastomer tubular cover sleeves. In some embodiments, the pre-expanded elastomer cable accessories 52, 52', 56' are splices, end covers, elbows, re-jacket sleeves, breakout sleeves, cable adapters, or other cable accessories.

[0059] In addition to the pre-expanded elastomer cable accessories 52, 52', 56', the pre-expanded cable accessory units 50, 50' can include other components attached to the holdout 54. In some embodiments, the pre-expanded cable accessory units 50, 50' further include a second elastomer cable accessory 52, 52', 56' attached to the holdout 54, and the holdout 54 is configured to hold the second elastomer cable accessory 52, 52', 56' in an elastically expanded (e.g., radially expanded) state (see, e.g., the elastomer cable accessory 56' shown in FIGS. 9A and 9B). For example, the pre-expanded cable accessory units 50, 50' can include a pre-expanded joint body mounted (and held in an expanded state by the holdout 54) on the holdout 54 as a first expanded elastomeric cable accessory 52', and a re-jacket sleeve mounted (and held in an expanded state by the holdout) on the holdout as a second expanded elastomeric cable accessory 56'. Additional non-elastomeric components or components that do not expand elastically, such as a metal shield mesh sleeve, may be mounted on the holdout. Exemplary pre-expanded cable accessory units are described, for example, in U.S. Patent No. 9,870,848 to Iyer, U.S. Patent No. 10,283,878 to Newman, and U.S. Patent No. 8,889,989 to Maher, the disclosures of which are incorporated herein by reference in their entirety.

[0060] In some embodiments, the pre-expanded cover units 50, 50' described herein may be provided as part of a kit of pre-packaged components and later assembled by an installer (e.g., a field installer). In some embodiments, the time-temperature indicators 10, 100 can be secured to the packaging 60 that houses the components of the kit (see, e.g., FIGS. 3A, 3B, 8A, and 8B).

[0061] The electrical cable accessory systems 5, 500 described herein can address issues and concerns related to the aging and degradation of the pre-expanded elastomeric cable accessories 52, 52', 56' provided in the pre-expanded cable accessory units 50, 50'. As described above, the pre-expanded cable accessory units 50, 50' (e.g., room temperature shrink cover sleeves) rely, for example, on a stretchable elastomeric material (i.e., the pre-expanded cable accessories 52, 52', 56') to properly seal the interface between the cable and the cable accessories 52, 52', 56'. The elastomeric material forming the cable accessories 52, 52', 56' relaxes over time based on time and temperature exposure (e.g., the elastomeric or tension-setting properties decrease). Ultimately, the relaxation of the elastomeric material reaches a limit (threshold), rendering the pre-expanded cable accessory units 50, 50' unable to function effectively (e.g., unable to provide the radial pressure necessary to seal the interface between the cable and the cable accessories 52, 52', 56'). When the ambient temperature shrinkable cable accessories are subjected to excessive heat exposure, they lose the ability to maintain sufficient elasticity to apply the intended minimum amount of compressive pressure to the substrate (e.g., the cable). Thus, the pre-expanded cable accessory units 50', 50' have a limited shelf life based on the tension setting characteristics because their elastomeric properties (i.e., the compressive force or clamping force or pressure due to elastic tension) decline (or relax) over a period of time when exposed to excessive heat. For example, when the cable accessories 52, 52', 56' reach the threshold of cumulative heat exposure, they are unable to provide the compressive force or clamping force or pressure necessary to properly and / or effectively seal the interface with the cable (or other connection). This compression can be important or essential to ensure proper sealing and / or dielectric withstand.

[0062] For this reason, such products generally have an expiration date, and the effective shelf life of the ambient temperature shrinkable cable accessories 52, 52', 56' (and the associated pre-expanded cable accessory units 50, 50') is roughly estimated. Since manufacturing cannot predict the actual handling and storage conditions of the product, the expiration date may be based on a conservative assumption. In some cases, the shelf life of the pre-expanded elastomeric cable accessory units 50, 50' is estimated to be about two years at 40°C (104°F). This approximate shelf life assumes that the pre-expanded elastomeric cable accessory units 50, 50' are stored for two years under continuous temperature exposure at 40°C (104°F). However, this assumption of continuous temperature exposure is not realistic with regard to how the majority of the pre-expanded cable accessory units 50, 50' are stored. As a result, the pre-expanded cable accessory units 50, 50' may reach their expiration date before their pre-expanded cable accessories 52, 52', 56' actually relax or thermally age beyond their effective limits.

[0063] The time-temperature indicators 10, 100 of the electrical cable accessory systems 5, 500 described herein address this problem by providing a more accurate individual assessment, display, or measurement of the thermal aging of the pre-expanded cable accessories 52, 52', 56' of the associated pre-expanded cable accessory units 50, 50'. Thus, it is advantageous to incorporate the time-temperature indicators 10, 100 into the pre-expanded cable accessory units 50, 50' during storage, or into the packaging 60 that houses the pre-expanded cable accessory units 50, 50', or into a kit of pre-packaged components, to accurately monitor the cumulative heat exposure and display to an observer the time of the threshold cumulative heat exposure at which the elastomeric properties of the pre-expanded elastomer cable accessories 52, 52', 56' have decreased. Thus, the time-temperature indicators 10, 100 can function as storage life indicators for the cable accessory units 50, 50' and can form a storage life indicator system (or part of a storage life indicator system) for the electrical cable accessory systems 5, 500.

[0064] The time-temperature-tension setting clock is started when the pre-expanded cable accessory systems 50, 50' (i.e., the pre-expanded elastomer cable accessories 52, 52', 56') expand, and thus, the time-temperature indicators 10, 100 should be started or activated to coincide with the expansion process in order to accurately reflect the storage life of the corresponding pre-expanded cable accessory systems 50, 50'.

[0065] Note that the electrical cable accessory systems 5, 500 (and associated time - temperature indicators 10, 100) described herein may include (or may be used with) non - expanding units or products that do not shrink at normal temperatures.

[0066] A method is provided for monitoring the cumulative heat exposure to a pre - expanded elastomeric cable accessory unit that covers an electrical cable and / or cable connection. As shown in the flowchart of FIG. 10, in some embodiments, the method can include the step of preparing an electrical cable accessory system. The electrical cable accessory system can include a pre - expanded cable accessory unit formed from an elastomeric material and a removable hold - out mounted within the elastomeric cable accessory, where the hold - out maintains the elastomeric cable accessory in an expanded state and is operative to allow the elastomeric cable accessory to elastically contract when the hold - out is removed from the elastomeric cable accessory. The pre - expanded cable accessory unit can further include a time - temperature indicator associated with the pre - expanded cable accessory unit, where the time - temperature indicator is configured to visibly change appearance in response to cumulative heat exposure (block 400). The method can further include the step of monitoring the visible change in appearance of the time - temperature indicator to determine whether the elastomeric material of the pre - expanded elastomeric cable accessory unit has received a threshold cumulative heat exposure (block 401).

[0067] A method of forming an electrical cable accessory system for monitoring cumulative thermal exposure to a pre-expanded elastomer-made cable accessory unit is also provided. As shown in the flowchart of FIG. 11, in some embodiments, the method can include the step of providing an electrical cable accessory system. The electrical cable accessory system can comprise a pre-expanded cable accessory unit formed from an elastomeric material and a removable holdout mounted within the elastomeric cable accessory, the holdout being operative to maintain the elastomeric cable accessory in an expanded state and to allow the elastomeric cable accessory to elastically contract when the holdout is removed from the elastomeric cable accessory. The pre-expanded cable accessory unit can further comprise a time-temperature indicator associated with the pre-expanded cable accessory unit, the time-temperature indicator being configured to visibly change appearance in response to cumulative thermal exposure (block 500). The method can further include the step of affixing the time-temperature indicator to the pre-expanded cable accessory unit or the packaging containing the pre-expanded cable accessory unit (block 501).

Claims

1. A method for monitoring cumulative thermal exposure to a pre-expanded elastomer cable accessory unit that covers an electrical cable and / or cable connection, said method comprising: ● providing an electrical cable accessory system, said electrical cable accessory system comprising: a pre-expanded cable accessory unit, a pre-expanded cable accessory formed from an elastomer material, and a removable holdout mounted within the elastomer cable accessory, said holdout operating to maintain the elastomer cable accessory in an expanded state and to enable the elastomer cable accessory to elastically contract when the holdout is removed from the elastomer cable accessory, a pre-expanded cable accessory unit; and a time-temperature indicator associated with said pre-expanded cable accessory unit, said time-temperature indicator being configured such that its appearance undergoes a visible change in response to cumulative thermal exposure; ● said method further comprising: monitoring a visible change in the appearance of said time-temperature indicator to determine whether the elastomer material of said pre-expanded elastomer cable accessory unit has received a threshold cumulative thermal exposure. A method.

2. The method of claim 1, wherein said time-temperature indicator comprises an indicator region and a reference region, said indicator region being configured such that its appearance undergoes a visible change in response to cumulative thermal exposure.

3. The method of claim 2, wherein said time-temperature indicator comprises a viscous liquid and a mobile medium, said visible change in appearance comprising movement of said viscous liquid along said mobile medium within said indicator region.

4. The method of claim 3, wherein when said viscous liquid has moved across the entire indicator region, the elastomer material of said pre-expanded elastomer cable accessory unit has received a threshold cumulative thermal exposure.

5. The method of claim 1, wherein said time-temperature indicator is affixed to said pre-expanded cable accessory unit or to the packaging containing said pre-expanded cable accessory unit.

6. The method of claim 1, wherein said pre-expanded cable accessory is a room temperature shrinkable cover sleeve. ​ ​ ​ ​ ​ ​

7. The threshold cumulative heat exposure for the pre-expanded cable accessory unit is about 40 °C (104 °F) over a period of about 730 days, The method according to claim 1.

8. The threshold cumulative heat exposure for the pre-expanded cable accessory unit is about 60 °C (140 °F) over a period of about 60 days, The method according to claim 1.

9. The time-temperature indicator is a thermochromic indicator, The method according to claim 1.

10. The time-temperature indicator is a liquid movement or dye diffusion indicator, The method according to claim 1.

11. The visible change in the appearance of the time-temperature indicator determines when the elastomeric material forming the pre-expanded cable accessory has received the threshold cumulative heat exposure, The method according to claim 1.

12. An electrical cable accessory system for covering an electrical cable and / or a cable connection, A pre-expanded cable accessory unit, A pre-expanded cable accessory formed from an elastomeric material, and A removable holdout mounted within the elastomeric cable accessory, Comprising, the holdout maintains the elastomeric cable accessory in an expanded state and operates to enable the elastomeric cable accessory to elastically contract when the holdout is removed from the elastomeric cable accessory, a pre-expanded cable accessory unit, A time-temperature indicator associated with the pre-expanded cable accessory unit, which has a visible change in appearance in response to cumulative heat exposure and is configured to notify an observer when the elastomeric material of the pre-expanded cable accessory unit made of elastomer has received the threshold cumulative heat exposure, a time-temperature indicator Comprising, An electrical cable accessory system.

13. The time-temperature indicator includes an indicator region and a reference region, and the indicator region is configured to have a visible change in appearance in response to the cumulative heat exposure, The electrical cable accessory system according to claim 12.

14. The time-temperature indicator is fixed to the pre-expanded cable accessory unit or the packaging containing the pre-expanded cable accessory unit, The electrical cable accessory system according to claim 12.

15. The time-temperature indicator includes a viscous liquid and a moving medium, and the visible change in the appearance includes the movement of the viscous liquid along the moving medium within the indicator region. The electrical cable accessory system according to claim 12.

16. The pre-expanded cable accessory unit includes two or more pre-expanded cable accessories made of elastomer, and at least one of the elastomer cable accessories is formed from an elastomer material different from that of other elastomer cable accessories. Each elastomer material has a degradation rate based on cumulative heat exposure. The visible change in the appearance of the time-temperature indicator determines when an elastomer cable accessory formed from an elastomer material having a fast degradation rate relative to other elastomer cable accessories has received a threshold cumulative heat exposure. The electrical cable accessory system according to claim 12.

17. The pre-expanded cable accessory is a cover sleeve that can shrink at normal temperature. The electrical cable accessory system according to claim 12.

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