SYSTEM FOR COMPENSATION OF EXPANSION/CONTRACTION OF A COOLING MEDIUM INSIDE A SEALED CLOSURE

A closure (100) protects telecommunications circuitry from environmental factors. The closure includes a base (128) having a sidewall (134) extending upwardly from a bottom (118), the sidewall (134) defining at least one cable port (122). The closure also includes a cover (126) that attaches to the base (128) to close an interior (130) of the closure (100). In addition, electronic circuitry (132) disposed within the interior (130) of the closure (100). Encompassing the electronic circuitry (132) is a cooling medium (138) dispersed through the interior (130). Further, a pressure regulating device (136) is placed in the interior (130) to maintain a viable internal operating pressure for the closure.

BACKGROUND

Fiber to the distribution point (FTTdp) is a fiber-optic based communication delivery network in which optical fibers are run in an optical distribution network from a central office to locations (i.e., distribution points) located near subscribers. Electrical cables complete the network, extending from the distribution points to the subscribers (e.g., to Optical Network Terminals or other subscriber equipment). The optical signals carried by the optical fibers are converted into electrical signals, which are carried by the electrical cables and the remaining distance to the subscribers.

Closures that hold electronic circuitry for transmitting or converting optical signals and electrical signals sometimes generate significant amounts of heat that can inhibit the operation of the electronic circuits within the closure.

Improvements are desired.

SUMMARY

The present disclosure relates to an internal pressure regulating closure that holds electronic circuitry to convert or transmit optical signals.

One aspect of the present disclosure relates to a sealed telecommunications closure for telecommunications circuitry comprising. The closure can include a housing that has a base and a cover that cooperate to define an interior; electronic circuitry located within the housing, the optical to electrical converter can be active electronic circuitry; a cooling liquid dispersed through the interior of the housing to cool electronics therein; and an expansion structure integrated with the housing to accommodate expansion of the cooling liquid caused by temperature spikes and to prevent breakage of a seal within the closure.

In accordance with an aspect of the disclosure, a closure for circuitry is disclosed. The closure for circuitry includes a base that has a sidewall extending upwardly from a bottom. The sidewall defines at least one cable port. The closure also includes a cover that attaches to the base to close an interior of the closure. The closure also includes electronic circuitry disposed within the interior of the closure. The electronic circuitry, in one example, is active electronic circuitry. The closure includes a cooling medium that encompasses the electronic circuitry. In addition, the closure comprises an internal pressure regulating device. In some examples, the pressure regulating device can comprise one of the following: an elastic material, an air piston, and a mechanical spring. In some examples, the closure can also comprise a seal that is placed between the cover and the base, wherein the seal prevents fluids from entering the enclosure.

In some examples, the cable port or ports can pass through any portion of the closure. One example is a two passage tube, such as a double channeled tube, that can be inserted in one of the ports to facilitate filling the interior with the cooling medium and also removing any air from the interior.

In accordance with an additional aspect of the disclosure, a method for assembly of the internal pressure regulating sealed closure includes providing a closure including a cover and a base having a sidewall extending upwardly from a bottom. The sidewall defines at least one cable port. The method includes placing electronic circuitry within the interior of the closure, the electronic circuitry being active. The method further includes securing the cover to the base to close an interior of the closure.

The method can also include inserting a two passage tube into the at least one cable port. Additionally, a cooling medium is dispersed into the interior of the closure through a first passage of the tube. As an appropriate amount of cooling medium is dispersed into the cavity, air is removed from the interior of the closure through a second passage of the tube. The method can also include sealing the tube.

Various cable ports can be provided, such as one or more, for incoming and outgoing cables, including fiber cables, copper cables, and/or hybrid cables.

DETAILED DESCRIPTION

The closure disclosed is configured to house active electronic circuitry related to fiber optic signal transmission or conversion. The closure also is configured to environmentally seal (e.g., a water-tight seal, a vapor-tight seal, etc.) the electronic circuitry from an external environment. Additionally, the closure is configured to be corrosion resistant. The closure can also house active electronic circuitry related to copper signal transmission where no fiber optic signals are present.

FIG. 1illustrates an example environment including an example closure100. The closure100is depicted in an underground container102. The underground container102includes a lid104that is generally flush with the ground surface106. Because the underground container102is positioned below the ground surface106, the container underground102is susceptible to flooding by water, especially rain water. As shown, water W can pool within the underground container102and partially or totally submerge equipment within the underground container102, including the closure100.

FIGS. 2-4show perspective views of the closure100. The closure100extends along a length L between a first end108and a second end110, along a width W between a first side112and a second side114, and along a height H between a top116and a bottom118. Additionally, the closure100includes at least one port122.

The port122is configured to receive a cable125. In some embodiments, the cable125is a fiber optic cable. In other embodiments, the cable125is a copper cable. The closure100can include a plurality of ports122in some embodiments. In the depicted embodiment, the ports122are configured to be positioned at the first end108of the closure100. However, it is contemplated that the ports122could be positioned at a side112,114or at the second end110of the closure100or other locations, or in combinations of locations. In some embodiments, the port122is configured to be positioned at an angle with respect to a side and an end of the closure. In the depicted embodiment, the closure can comprise a plurality of ports122in a line on end108.

FIG. 3shows an exploded view of the closure100. The closure100includes a housing112having a cover126, a base128, an interior130, a heat generating element such as electronic circuitry132, and the ports122. The cover126and the base128cooperate to define the interior130. Within the interior130, the electronic circuitry132is disposed. Attached to the base128is at least one port122for cables. The closure100is water-tight at the various joints and intersections of parts.

In the example shown, the base128includes a sidewall134extending upward from the bottom118. The cover126attaches to the sidewall134opposite the bottom118. The base128and/or cover126can be configured to disperse heat generated by the electronic circuitry132within the interior130of the closure100. In transferring the heat generated, the closure can facilitate transferring heat away from the electronic circuitry132to the environment surround the closure100. For example, the base128and/or cover126can be formed of a thermally conductive material (e.g., a metal). In an example, the base128and/or cover126can be formed of die cast aluminum. In other examples, the base128and/or cover126can be formed of thermally conductive plastics.

In one embodiment, the closure100can further comprise a seal120. When securing the closure, the seal120can be placed between the cover126and the base128such that seal120provides an additional measure of protection against outside elements. In a particular embodiment, the seal120can aid in providing an air tight and water tight barrier. The seal can be comprised of plastic, rubber, or silicone material that can prevent liquids from entering the closure and exiting the closure.

The electronic circuitry132can be disposed within the interior130. The electronic circuitry132is active (i.e., powered) and produces heat during normal operation. The electronic circuitry132is configured to radiate heat in the interior130of the closure100. In some embodiments, the electronic circuitry132includes a circuit board with components mounted thereto.

FIG. 3also shows a pressure regulating device136. As discussed earlier, the ability to use the closure in an external environment requires protection against the environment, which can be use by properly sealing the closure. In addition, to insure proper function of the components in the closure, the environment inside the closure must also be considered. In an embodiment, the heat generated by the electronic circuitry132be can dissipated by a cooling medium138contained within interior130. The cooling medium138acts as both a cooling agent and a heat transfer medium from the electronic circuitry132. In other embodiments, the cooling medium acts as a barrier for humidity and other environmental factors such as air, moisture, excessive temperatures, and excessive temperature ranges. Introducing environment factors to the electronic components can cause malfunctions in the components. The cooling medium138and the pressure regulating device136regulate the heat and pressure in interior130.

During operation, the cooling medium138is subjected to temperature changes that cause pressure to increase and decrease inside the closure100. Heat generated by the internal components is transported through the cooling medium138to the inside of housing112of the closure100. Subsequently, the generated heat is transferred from the closure100to the external environment. The cooling medium138creates an even surface temperature on the closure body. This even surface temperature reduces the thermal hot-spots and reduces overall temperature of the closure, improving thermal exchange. In example embodiments, the cooling medium138can be made out of natural oil, petrochemical oil, or other synthetic materials. In addition, the cooling medium138can possess other characteristics that make it viable for use with electric components such as being non-corrosive, non-electrically conductive and nonreactive with the structure and function of the internal components.

When the cooling medium138possesses the physical characteristic of low compressibility, an increase in internal pressure occurs when the cooling medium is heated. As stated earlier, the heat is generated from the activity of the enclosed electronic circuitry132. To counteract the increase in internal pressure, a pressure regulating device136can be used. A purpose of the pressure regulating device136is to ensure that the pressure inside the closure100does not exceed the maximum allowable internal operating pressure. The pressure regulating device136can be any device that stores potential energy generated by the pressure of the cooling medium. In addition, the pressure regulating device136can release the stored potential energy when the cooling system no longer exerts pressure on the pressure regulating device136. Examples of the pressure regulating device136can include any pressure storing system internal to the closure100such as an elastic material, air piston, or mechanical springs.

In certain implementations, the electronic circuitry132is configured to convert between optical signals and electrical signals. In such implementations, optical signals carried over an optical fiber cable can be converted to electrical signals by the electronic circuitry132, and the electrical signals can be carried over the electrical conductor(s). Accordingly, signals carried between a central office and a subscriber can be carried over optical fibers along a majority of the network to closure100and carried over electrical conductors only over short distances between the closure100and the subscriber.

FIG. 4shows an embodiment ofFIG. 2with a plurality of ports122. One of the ports in the plurality of ports can be dedicated to providing a pathway to introduce the cooling medium138to the closure100. In this embodiment, a fill plug123is provided. Fill plug123includes a two passage tube124that can be connected into one of the ports122. The tube124in the example includes two parallel channels. One channel can be used to introduce the cooling medium into the closure. A second channel in the dual sided tube can be used to evacuate air from a sealed chamber. A seal127is then provided on tube124after closure100is filled with the cooling medium138.

FIG. 5illustrates an overview process of sealing the electronic components in the closure. In the process500of assembling the closure, the process flows to operation505where a closure is provided. The cover126and base128can be configured such that that when the cover126is placed on the base128an interior space is defined. Flowing to operation510, an element can be placed in the interior. In an example embodiment, the element can be an electronic circuitry132. While in operation, the electronic circuitry132can generate heat. In order to ensure that the generated heat does not inhibit the function of the enclosed electrical circuitry, the heat can be transferred from the circuit to the closure and finally to the environment surrounding the closure.

Moving to operation515, the cover126is secured to the base128. The cover can be attached to the base by an attachment device such as screw, bolt, adhesive, etc. Reducing the encroachment of environmental factors into the interior130can be aided by including a sealing mechanism. The seal120can be placed between cover126and base128which can decrease air and fluid permeability between the joints of the cover126and base128. Transitioning to operation520, a tube124can be placed into a port122. The port122can be defined by an aperture in a wall of the closure. In one embodiment, the tube124can be double sided where the tube has two parallel channels. Accordingly, both channels can serve a purpose. For example, in moving to operation525, a cooling medium138can be introduced to the interior130through one channel of the double sided tube, and air can be evacuated from the other channel.

While the appropriate amount of cooling medium138has been dispersed into the interior130, the process can include operation530where the second channel can be used to remove air from the interior130. Removing the air decreases the environmental factors that can interact with the electronic circuitry132during operation and allows the interior130to fill with the cooling medium138. Operation535illustrates sealing the tube124after the cooling medium has been dispersed and the air has been removed from the interior. In other embodiments the tube can be mechanically sealed or hermetically sealed using heat. At operation540, telecommunications signals are processed by the interior components in closure100.

One aspect of the closure100includes: a closure for regulating internal heat generation including an internal pressure regulating device136.

Another aspect of the closure100includes: a base128having a sidewall134extending upwardly from a bottom118, such that the closure defines an interior130; and a cover126that attaches to the base128, and a pressure regulating device136located in the interior130.

A further aspect of the closure100includes: at least one cable port122; a cooling medium138dispersed through the interior130; and a pressure regulating device136located in the interior130, wherein the device is configured to react to a pressure changes in the housing, wherein the pressure change is exerted by the cooling medium138.

A further aspect of the closure100includes: electronic circuitry132, such that electronic circuitry132is orientated in the interior130and encompassed by the cooling medium138.

In one example, one port122includes a fill plug123, one port122includes a fiber cable, and one port122includes a copper cable.

Connector devices129connect cables125to closure100. Connector devices can provide sealing and pull protection. Cables125extend into closure100and connect to the electronic circuitry132and/or to other cables.

Another aspect of the present disclosure relates to one or more environmentally sealed closures adapted for housing equipment (switching circuitry, optical-to-electrical conversion circuitry, etc.) used in systems for readily facilitating making telecommunications service upgrades or other changes in service in the field. In certain examples, system upgrades can include switching from an electrical feed line coupled to a service provider's central office to a fiber optic feed line coupled to the service provider's central office.

Referring toFIG. 6, another example closure200is illustrated for use in a system202for upgrading telecommunications service in the field. The example closure200depicted is a distribution point unit (DPU). While the example embodiments discussed herein are with reference to a distribution point unit (DPU) type closure200, other types of closures may be used. The closure200is illustrated and described in more detail with reference toFIGS. 7-11.

The closure200can hold electronic circuitry204(e.g., opto-electrical conversion electronics) (seeFIG. 7) for converting optical signals to electrical signals and for converting electrical signals into optical signals (i.e., conversion circuitry). The closure200is configured to receive both an optical fiber carrying the optical signals and an electrical conductor carrying the electrical signals. The optical signals are transmitted to and from the closure200by an optical fiber line206and the electrical signals are transmitted to and from the closure200by an upgrade line(s)208including at least one twisted wire pair. Where more than one upgrade line208is provided, the lines208can be encased within a common jacket (i.e., tube, cable jacket, sleeve) or routed as separate twisted wire pairs. The closure200can include a passive optical power splitter S to split the optical fiber line206within the closure200before entering the electronic circuitry204, although alternatives are possible. The closure200is also configured to environmentally seal (e.g., a water-tight seal, a vapor-tight seal, etc.) the electronic circuitry204from an external environment.

Referring toFIG. 7, the example closure200is depicted in another system202a. The system202acan also include a switching and termination enclosure212that has a housing that contains switching circuitry214. The switching and termination enclosure212can include an overmold made of a plastic resin material. The switching circuitry214can be connected to a subscriber line216including at least one twisted wire pair and also can be connected to the upgrade line208. The switching circuitry214can further be connected to a service provider basic line218including at least one twisted wire pair. The switching circuitry214is operable in a first state where subscriber line216is connected to the service provider basic line218such that a first service (e.g., a basic service) is provided to the subscriber. The switching circuitry214is also operable in a second state where the subscriber line216is connected to the upgrade line208such that the subscriber is disconnected form the first service and connected to the upgrade line208such that a second service (e.g., UDSL, G. FAST, an upgraded service such as a faster service that may include extended fiber optic connectivity) is provided to the subscriber.

The example closure200and the switching and termination enclosure212can each include environmentally sealed protective housings. The closure200can be factory assembled with the protective housing and all cable entrance locations sealed. In certain examples, the protective housing of the closure200is not intended or configured to be opened in the field. The switching and termination enclosure can have a protective housing designed to be re-enterable in the field. Example configurations for the closure200are disclosed by U.S. Provisional Patent Application Nos. 61/135,478; 62/155,944; 62/186,915; and 62/057,540, which are all hereby incorporated by reference in their entireties. Example switching circuit and power routing configurations for the system202aare disclosed by U.S. Provisional Patent Application No. 62/194,140 which is hereby incorporated by reference in its entirety. Examples of ruggedized and sealed connectors and adapters that can be incorporated on stub cables of the closures or onto the housings of the closures or elsewhere in the system are disclosed by U.S. Pat. Nos. 7,744,288; 7,686,519 and U.S. patent application Ser. No. 14/360,383 which are all hereby incorporated by reference in their entireties.

Referring toFIGS. 8 and 9, the example closure200can include a housing236that has a first end220, an opposite second end222. The housing236of the closure200includes a first side224and an opposite second side226that each extend between the first and second ends220,222. The closure200includes a base228and a cover230that cooperate to define an interior232. The switching circuitry214is disposed within the interior232of the closure200. For example, a circuit board234can be disposed within the interior232of the closure200. The circuit board234can include the opto-electrical conversion electronics204.

The base228and/or cover230can be configured to disperse heat generated by the electronic circuitry204. For example, closure200can be a rigid container where the base228and/or cover230can be formed of a thermally conductive material (e.g., a metal). In an example, the base228and/or cover230can be formed of Al Die cast. In other examples, the base228and/or cover230can be formed of thermally conductive plastics (e.g., polypropylene). The closure200may be thin so that it can still radiate heat as aluminum. However, a system202including an upgraded, faster, service with extended fiber optic connectivity may need a closure design that can handle increased heat loads of a G. fast chipset.

The closure200in accordance with the present disclosure can be filled with cooling liquid210(e.g., cooling medium) to help dissipate heat generated by the electronic circuitry204and to help prevent arching. The cooling liquid210can help to eliminate localized hot spots in the closure200.

As used herein, the term, “liquid,” is defined as including cooling oils, hydraulic fluids, or other liquids having heat transfer properties suitable for cooling.

The cooling liquid210can be an incompressible fluid, for example, oil. In one example, the cooling liquid210can be a natural oil, petrochemical oil, and/or a synthetic material, although alternatives are possible. Rather than have a closure filled with air, which acts as an insulator, oil can be used to help eliminate air voids. No air voids means that there would be no pressure differential. Thus, the closure200can be submerged and there would be no force that exists to drive water into the closure200. Such a design can allow the closure200to be made with alternate materials that are not bulky, rigid, or complex, but rather lighter and easy to manufacture. The oil can be supplied to the closure200through an injection port (e.g., one way valve; fill plug), although alternatives are possible. The closure200can further include a bleed valve (not shown) that can be used to bleed air out of the closure200.

The cooling liquid210can also be compatible with both a plastic closure and the electronics housed therein. The cooling liquid210(i.e., oil, a better conductor of heat than air) can help provide better thermal management and heat dissipation compared to typical thermal conduction methods of using clay. By eliminating the thermal bottleneck of the interior air space by including the cooling liquid210, the closure200can still radiate enough heat to keep peak temperatures lower despite being made of a poor conductor, such as plastic.

In certain examples, the closure200can include a pump P (seeFIG. 7) to circulate the cooling liquid210within the closure200. The pump P can be arranged and configured to power on when a temperature threshold is reached. The pump P encourages internal circulation of liquid between the interior surface of the housing236and any heat generating circuitry so that heat can more readily be transferred out of the housing236. The pump P circulates liquid within the housing236to help prevent localized hot spots around the heat generating circuitry.

In one example, the circuit board234can include one or more transformer relays240that can each have heat transfer fins242that are exposed to the cooling liquid210to help dissipate heat to the cooling liquid210. Other heat generating elements (e.g., chips, optical/electrical converter, etc.) on the circuit board234can also include heat transfer fins242to help dissipate heat. In other examples, chips or active components may have integrated temperature sensors within the closure200for measuring temperature spikes.

In certain examples, the closure200can include an integral expansion structure244(e.g., rubber membrane, disc, circular corrugating member, ribs, etc.)(seeFIG. 7). The integral expansion structure244may be integrally formed as one single piece with the housing236of closure200, although alternatives are possible. In one example, the integral expansion structure244can be positioned on the base228, although alternatives are possible. For example, the integral expansion structure244can be positioned on the cover230. In still other examples, the integral expansion structure244may be positioned on both the base228and the cover230.

The integral expansion structure244can allow the rigid closure200to expand and contract due to the cooling liquid210heating within the sealed closure200. The integral expansion structure244can expand to accommodate expansion of the cooling liquid210caused by temperature rises or spikes, which can help to prevent the breakage of a seal238located within the closure200as the cooling liquid210heats up. The integral expansion structure244can be made of an elastic material such that once the temperature is reduced, the integral expansion structure244can contract back to its original state.

In other examples a piezo-electric fan (not shown) may be used to management temperature spikes in the example of an air filled DPU. The piezo-electric fan would power on when internal temperatures hit a predetermined threshold limit, but remain off at all other times. In other examples, a fluid paddle (not shown) can be used to increase internal convection in the example of a liquid filled/cooled DPU.

When securing the closure200, the seal238can be placed between the cover230and the base228such that seal238provides an additional measure of protection against outside elements. In a particular embodiment, the seal238can aid in providing an air tight and water tight barrier. The seal can be comprised of plastic, rubber, or silicone material that can prevent liquids from entering the closure and exiting the closure.

The optical fiber line206can be routed into the closure200through a first port246and the upgrade line(s)208can be routed out of the closure200through a second port248. The first and second ports246,248can each include a sealing arrangement250. In certain examples, the sealing arrangement250can be a fluid seal arranged and configured about the optical fiber line206and the upgrade lines208.

In certain examples, the closure200can include: 1) a fiber optic stub252(seeFIG. 6) having a ruggedized single or multi-fiber connection port or connector254for connecting to the optical fiber line206; or 2) a ruggedized fiber optic adapter (not shown) mounted to the closure for receiving a ruggedized connector of the optical fiber line206; or 3) a fiber optic stub (not shown) terminated by a non-ruggedized single or multi-fiber connector (not shown); or 4) a non-connectorized stub (not shown) that is spliced to the optical fiber line206; or 5) an optical fiber (not shown) that is routed between the closure200and the switching and termination closure212. The optical fiber can be adapted for connection to the optical fiber line206at the switching and termination enclosure212can be factory sealed relative to the closure200so as to be part of a factory integrated stub assembly that is routed from the closure200to the switching and termination closure212.

In certain examples, the optical fiber signals pass through the switching and termination closure212before being routed to the closure200. In certain examples, the upgrade line(s)208and the optical fiber are routed between the closure200and the switching and termination closure212by a hybrid fiber optic/electrical cable (not shown). In other examples, separate cables route the optical fiber and the upgrade line(s)208between the closures200,212.

The upgrade line(s) can carry electrical power from the switching and termination closure212to the closure200for use in powering the optical-to electrical circuitry204. Power can be provided to the switching and termination enclosure212from the subscriber locations via the subscriber lines216.

In certain examples, the switching and termination enclosure212includes: 1) a fiber optic stub having a ruggedized single or multi-fiber connection port or connector for connecting to the optical fiber line206(not shown); or 2) a ruggedized fiber optic adapter (not shown) mounted to the switching and termination enclosure212for receiving a ruggedized connector (not shown) of the optical fiber line206and the non-ruggedized connector (not shown) of the optical fiber stub (not shown); or 3) a fiber optic stub terminated by a non-ruggedized single or multi-fiber connector (not shown); or 4) a non-connectorized stub that is spliced to the optical fiber line (not shown).

In certain examples, the switching and termination enclosure212and the closure200are positioned together within a further environmentally sealed housing (not shown).

In one example, one or more remote copper switches256(RCS)(seeFIGS. 10-11) that define the switching circuitry214can be integrated onto the circuit board234inside of the closure200, although alternatives are possible. The RCS can be surrounded by the cooling liquid210within the interior232of the closure200. In the example depicted, there are four remote copper switches256, although alternatives are possible. Passive electronics of each remote copper switch256can be placed inside of the closure200. Thus, the individual RCS switching circuitry214can be combined with the circuit board234instead of separately in each RCS. Thus, small printed circuit boards that reside in the RCS are no longer needed. Nor is there any need for complicated overmolding of the RCS circuitry. By eliminating these parts and integrating their function onto the circuit board234, there can be obvious cost and logistics advantages.

From the forgoing detailed description, it will be evident that modifications and variations can be made without departing from the spirit and scope of the disclosure.

PARTS LIST