Heat transfer unit for prefabricated vessel

Vessel assemblies, heat transfer units for prefabricated vessels, and methods for heat transfer prefabricated vessel are provided. A heat transfer unit includes a central rod, and a plurality of peripheral rods surrounding the central rod and connected to the central rod. The plurality of peripheral rods are movable between a first collapsed position and a second bowed position, wherein in the second bowed position a midpoint of each of the plurality of peripheral rods is spaced from the central rod relative to in the first position. The heat transfer unit further includes a heat transfer element connected to one of the plurality of peripheral rods.

FIELD OF THE INVENTION

The present disclosure is related generally to heat transfer units for use in prefabricated vessels, such as pressure vessels.

BACKGROUND OF THE INVENTION

Vessels for storage of substances such as liquids or gases have been utilized in a variety of industries for a variety of purposes. For example, pressure vessels have been utilized for hydrogen, natural gas, and other gas storage needs. In particular, vessels have been utilized in mobile gas storage markets, such as in the automotive industry, heavy machinery industry, and portable generator industry. Stationary gas storage markets have additionally utilized storage vessels for liquid or gas storage needs.

In general, it is desirable to maintain the fluids stored in a vessel at desired temperatures. Thus, heating of the fluids may be required in colder environments, and cooling of the fluids may be required in hotter environments. Presently known heat transfer units for storage vessels generally fall into three groups: large, bulky units around which a vessel must be manufactured; large, sectional units which include various sections, each of which must be individually inserted into the vessel and then assembled therein; and small units which can be inserted into the vessel in preassembled form but do not provide sufficient heat transfer throughout the entire vessel.

Each of these approaches has disadvantages. Large, bulky units require the time and expense of having vessels manufactured around the units, and the vessels must be destroyed to access the units. Large, sectional units require the time and expense of difficult in-vessel assembly. Small units have limited heat transfer capabilities.

Accordingly, improved heat transfer units for vessels, such as prefabricated vessels, are desired in the art. In particular, heat transfer units which can be efficiently inserted into prefabricated vessels, and which provide improved heat transfer capabilities throughout the vessels, would be advantageous.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with one embodiment, the present disclosure is directed to a heat transfer unit for a prefabricated vessel. The heat transfer unit includes a central core extending along and defining a longitudinal axis, wherein the central core is operable to provide heat transfer. The heat transfer unit further includes a plurality of fins connected to the central core. Each of the plurality of fins extends from the central core at an angle to the longitudinal axis when in a base position. Each of the plurality of fins is flexible and biased towards the base position such that each of the plurality of fins returns to about the respective base position when not under the influence of an external biasing force.

In accordance with another embodiment, the present disclosure is directed to a vessel assembly. The vessel assembly includes a prefabricated vessel including a shell, the shell defining an interior. The vessel further includes a heat transfer unit insertable into the interior of the prefabricated vessel. The heat transfer unit includes a central core extending along and defining a longitudinal axis, wherein the central core is operable to provide heat transfer. The heat transfer unit further includes a plurality of fins connected to the central core. Each of the plurality of fins extends from the central core at an angle to the longitudinal axis when in a base position. Each of the plurality of fins is flexible and biased towards the base position such that each of the plurality of fins returns to about the respective base position when not under the influence of an external biasing force.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, terms of approximation, such as “generally”, “about”, or “approximately”, include values within twenty percent greater or less than the stated value. When used in the context of an angle or direction, such terms include within twenty degrees greater or less than the stated angle or direction. For example, “generally vertical” includes directions within twenty degrees of vertical in any direction, e.g., clockwise or counter-clockwise.

The present disclosure is generally directed to heat transfer units for use in prefabricated vessels. A unit in accordance with the present disclosure includes a central core which provides heat transfer. For example, the central core may be a tube through which a heat transfer fluid may be flowed, or may be a rod which can be heated or cooled (for example via an electric heater or thermoelectric cooler) to facilitate heat transfer. Further, a plurality of fins may be connected to the central core. Each fin may extend into the vessel when inserted therein. Further, each fin may have a base position and be flexible such that the fin can be moved from that base position by an external biasing force. However, each fin may further be biased towards the base position such that, when the external biasing force is removed, the fin returns to about the base position. Such design of the fins advantageously allows for efficient heat transfer within the vessel (i.e. from the core through the fins to the vessel interior fluid). Additionally, such design facilitates easy and efficient insertion of the unit into and removal of the unit from the vessel, without for example requiring destruction of the vessel to access the unit.

Referring now toFIGS. 1 through 3, embodiments of a vessel assembly10in various positions are illustrated. Vessel assembly10may include a prefabricated vessel12and a heat transfer unit14. A prefabricated vessel10is generally a vessel12constructed independently of a heat transfer unit14, and which may be utilized to store a fluid, such as a gas or liquid. Some examples of such fluids include hydrogen and natural gas, although it should be understood that the present disclosure is not limited to such examples. In some exemplary embodiments, a vessel10may be pressure vessel10, designed to contain a fluid at a pressure above atmospheric. A vessel12may include, for example, a shell20generally defining an interior22of the vessel12. An opening24may further be defined by the shell20for accessing the interior22.

In some embodiments, the stored fluid may be provided into the vessel12separately from the heat transfer unit14. Alternatively, the stored fluid may be supplied through the heat transfer unit14. In some embodiments, vessel12may further include, for example, a cap26which may fit into opening24to close and/or generally seal the interior22of the vessel12. Alternatively, as shown, heat transfer unit14may include the cap26such that the heat transfer unit14also closes and/or generally seals the interior22of the vessel12. Cap may, for example, include outer threads which interface with inner threads of the portion of the shell20defining the opening24, or may alternatively utilize another suitable closure/sealing mechanism to facilitate closing and/or sealing of the interior22.

Referring now also toFIGS. 4 and 5, heat transfer unit14may be insertable into the interior22of vessel12through opening24. As shown, heat transfer unit14may include a central core30which extends along and defines a longitudinal axis32(which may for example correspond to a centerline axis of the vessel12). The central core30may be operable to provide heat transfer. For example, in some embodiments, the central core30may be a tube. Further, a heat transfer fluid may be disposed within and flowable through the tube to facilitate heat transfer within the interior22. Alternatively, the central core30may be a rod. In these embodiments, the rod may be heated or cooled to facilitate heat transfer within the interior22. In some embodiments, the central core30may extend generally linearly along the longitudinal axis32. Alternatively, as shown, the central core30may have a coiled structure (such as around the axis32) or a helical structure, which may in exemplary embodiments be a double helical or double helix structure. The helical structure may be formed from a single member (tube, rod, etc.) or from multiple members.

In exemplary embodiments, the helical structure may be formed from a metal. For example, steel (which in some embodiments may be stainless steel), copper, or aluminum may be utilized. Alternatively, other suitable materials which facilitate heat transfer (such as by being electrically or thermally conductive) may be utilized.

When the heat transfer unit14is inserted into the vessel12, portions of the central core30may remain exterior to the vessel12. This allows heat transfer fluid, electricity, etc. to be applied to the central core30to facilitate heat transfer within the interior22. For example, a fluid inlet, valve, and/or suitable electric connector mechanism may be provided in the central core30exterior to the vessel12.

In some embodiments, the heat transfer unit14may further include a fluid supply tube40. The fluid supply tube40may supply fluid to be stored in the interior22of the vessel12to the interior22, such as through one or more outlet openings42defined in the tube40. In some embodiments, the tube40may extend along the longitudinal axis32. For example, in embodiments wherein the central core30has a helical structure, the tube40may extend through the helical structure such that the central core wraps helically around the tube40. An opening42of the tube40may be at a longitudinal end of the tube40, and/or one or more openings42may be defined along the length of the tube40. Additionally, a valve44may be included on the tube40to regulate the flow of fluid through the tube40into the interior22. When the heat transfer unit14is inserted into the vessel12, the valve44may remain exterior to the vessel12. The fluid supply tube40may extend only slightly into the interior22, such as just past the opening24as shown, or may extend through a significant portion of a length of the vessel12.

Heat transfer unit14may further include a plurality of fins50which are connected to the central core30. Such connection of each fin50to the central core30may be a rigid connection, such as via brazing, welding, or another suitable connection method. In some embodiments, a fin50may be connected on one end to the central core30, with the other end extending therefrom. In other embodiments, a fin50may extend through the central core30and be connected to the central core30at a midpoint of the fin50, such that both ends extend from the central core30. In general, the plurality of fins50may be arranged in one or more rows along the longitudinal axis32, and each row may include one or more fins50which may for example be arranged in an annular array.

In some embodiments, one or more of the fins50may provide heat transfer. Such fins50may in some embodiments be formed from a metal. For example, steel (which in some embodiments may be stainless steel), copper, or aluminum may be utilized. Alternatively, other suitable materials which facilitate heat transfer (such as by being electrically or thermally conductive) may be utilized. Heat may be transferred to such fins50from the central core30via contact with the central core30.

Additionally or alternatively, one or more fins50may include an auxiliary device60coupled thereto, as discussed herein. Such fins50may or may not provide heat transfer. Accordingly, such fins50may be formed from a material suitable for heat transfer, as discussed above. Alternatively, such fins50may be formed from a suitable plastic or other non-conductive material.

FIG. 4illustrates one embodiment of a fin50in accordance with the present disclosure. In these embodiments, fin50is a pin, and thus has a generally circular cross-sectional profile.FIG. 5illustrates another embodiment of a fin50in accordance with the present disclosure. In these embodiments, fin50is a ribbon, and thus has a generally rectangular cross-sectional profile which is generally flat. Alternatively, other suitable shapes and cross-sectional profiles may be utilized. In some embodiments, one or more fins50may extend linearly, while in additional or alternative embodiments, one or more fins50may extend curvilinearly.

Each fin50may extend from the central core30, such as at an angle52to the longitudinal axis32, when in a base position. The base position is generally a position that each fin50generally assumes when not under the influence of an external biasing force which moves the fin50relative to this position. In some embodiments, for example, the angle52may be between 0 degrees and 80 degrees from perpendicular to the longitudinal axis32, such as between 0 degrees and 70 degrees from perpendicular to the longitudinal axis32, such as between 0 degrees and 60 degrees from perpendicular to the longitudinal axis32. It should be understood that the plurality of fins50need not each have the same angle52. For example, for some fins, the angle52may be between 0 degrees and 20 degrees from perpendicular to the longitudinal axis32, such as between 0 degrees and 15 degrees from perpendicular to the longitudinal axis32, such as between 0 degrees and 10 degrees from perpendicular to the longitudinal axis32.

Each fin50may be sufficiently rigid to assume the base position when not under the influence of an external biasing force. However, each fin50may further be relatively flexible and elastically deformable, resulting in a bias towards the base position. Accordingly, when an external biasing force is applied to a fin50, the fin50may move/bend/pivot from the base position. However, when the external biasing force is removed, the fin50may return to about the base position.

For example, as discussed,FIG. 1illustrates the unit14being inserted into a vessel12. During such insertion, the fins50may each encounter resistance due to contact with the exterior of the shell20. As the unit14enters the vessel12through the opening24, each fin50may move/bend/pivot due the external basing force resulting from contact with the shell20. Each fin50may thus be moved to a position which allows entry through the opening24. Once the fin50passes through the opening24and is fully in the interior22, such that any external biasing force via contact, etc., has been removed, the fin50may return to the base position, as shown inFIGS. 1 and 2.

As discussed, in some embodiments, a heat transfer unit14may further include one or more auxiliary devices60coupled to one or more fins50. An auxiliary device60may be utilized to, for example measure various characteristics of the fluid within the vessel12, take samples of the fluid, etc. For example, an auxiliary device60may be a sensor, such as a chemical sensor; a sampling device, such as a pitot tube; a thermocouple; or a pressure transducer.