A recharging dehydrating breather for providing dehydrated air to electrical components includes a desiccant chamber configured to hold desiccant and a heating element configured to heat the desiccant held in the desiccant chamber to at least partially eliminate water. The device further includes a housing configured to hold the desiccant chamber and the heating element, an outlet configured to provide an outlet to guide the water away from the housing, and the outlet configured to be heated by the heating element. A process of configuring a recharging dehydrating breather for providing dehydrated air to electrical components is also disclosed.

FIELD OF THE INVENTION

The invention relates to a dehydrator for removing moisture from air. More particularly, the invention relates to a recharging dehydrating breather for high power electrical equipment and other devices.

BACKGROUND OF THE INVENTION

FIGS. 1,2,3, and4depict a known automatic recharging dehydrating breather100, i.e., the ARDB2 manufactured by Waukesha Electric Systems, Inc. (Waukesha, Wis.). The dehydrating breather100typically removes moisture from the air of load tap changer tanks, conservators, sealed tanks, control cabinets and the like. For convenience, the operation of the dehydrating breather100will be described with reference to a load tap changer tank which stores oil used to cool the tap changer.

A headspace of the tank of the load tap changer (not shown) is connected to the dehydrating breather100by a pipe, tube, hose, etc. When the tank exhales, air flows from the headspace of the tank, through the hose, and into the dehydrating breather100, which vents the air to the atmosphere. When the tank inhales, air is drawn into the dehydrating breather100and passes through a desiccant, then through the hose to the tank. The desiccant dehumidifies the air provided to the tank, and, over time, typically becomes saturated with water. The dehydrating breather100removes the water absorbed by the desiccant using a process called recharging or regeneration. During a regeneration cycle, an electric heating element, disposed inside the dehydrating breather100, evaporates the water from a silica gel desiccant, and an embedded PC board ensures that regeneration occurs only during tank exhalation.

FIG. 5depicts a cross-sectional view of a dehydrating breather100, annotated to identify the various components, air flows and water flow. The dehydrating breather100typically includes a bottom molding with a condensate water filter vent (water drain), a tube and a top molding with the PC board and a top cap.

The top molding includes slots through which air is normally drawn into and expelled from the dehydrating breather100through a slot. During regeneration, the heating elements evaporate the water absorbed by the silica gel desiccant, which condenses on the inner surface of the tube, drains to the bottom molding and passes through the filter vent.

During cold weather operation, particularly when the ambient air temperature falls below 32° F., water in the filter vent can typically freeze, which prevents additional condensate from draining out and eventually renders the dehydrating breather100inoperable due to the build-up of water within the desiccant chamber.

Accordingly, a low cost and/or low complexity solution to prevent the filter vent from freezing is needed.

SUMMARY OF THE INVENTION

The foregoing needs are met, to a great extent, by the invention, wherein in one aspect a technique and apparatus are provided that provides a low cost and/or low complexity solution to the filter vent freezing.

In accordance with one embodiment, a recharging dehydrating breather for providing dehydrated air to electrical components includes a desiccant chamber configured to hold desiccant, a heating element configured to heat the desiccant held in the desiccant chamber to at least partially eliminate water, a housing configured to hold the desiccant chamber and the heating element, an outlet configured to provide an outlet to guide the water away from the housing, and the outlet configured to be heated by the heating element.

In accordance with another embodiment a recharging dehydrating breather for providing dehydrated air to electrical components includes chamber means for holding desiccant, heating means for heating the desiccant held in the chamber means to at least partially eliminate water, means for housing the chamber means and the heating means, outlet means to provide an outlet to guide the water away from the housing means, and the outlet means being heated by the heating means.

In accordance with yet another embodiment, a process of configuring a recharging dehydrating breather for providing dehydrated air to electrical components includes holding a desiccant in a chamber, heating the desiccant held in the chamber with a heating element to at least partially eliminate water, housing the chamber and the heating element in a housing, arranging an outlet to guide the water away from the housing, and heating the outlet with the heating element.

DETAILED DESCRIPTION

The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. Embodiments of the invention advantageously provide a recharging dehydrating breather that operates in cold weather by reducing or eliminating frost and ice formation within the condensate water flow path of the dehydrating breather without substantially increasing the complexity, cost, power requirements, failure rate, etc., of the device.

In one aspect, the recharging dehydrating breather may include a desiccant chamber, a heating element, and a water outlet that is heated by the heating element.

In a further aspect, the recharging dehydrating breather may include a desiccant chamber, a thermal conductor, and a condensate vent. The desiccant chamber may include desiccant and a heater. The thermal conductor may be thermally coupled to the heater and may include a water inlet fluidly coupled to the desiccant chamber, a central bore, and a water outlet. The condensate vent230may include a central bore fluidly coupled to the thermal conductor water outlet and a screen may be disposed over the water outlet. In another aspect, the recharging dehydrating breather also may include a thermal coupler with a disc that abuts a bottom of the heater and a threaded shaft that may be threaded into a threaded upper portion of the thermal conductor central bore.

FIG. 6shows a perspective of a recharging dehydrating breather according to an aspect of the invention;FIG. 7shows a top view of a recharging dehydrating breather according to the aspect of the invention ofFIG. 6;FIG. 8shows a front view of a recharging dehydrating breather according to the aspect of the invention ofFIG. 6; andFIG. 9shows a side view of a recharging dehydrating breather according to the aspect of the invention ofFIG. 6. In particular,FIGS. 6,7,8, and9show the details of a dehydrating breather200. The dehydrating breather200may include a body240, an upper housing242with an electric controller, and a removable cap244. The lower housing202, body240, and upper housing242may be each made from plastic, such as a polycarbonate or similar material, or, alternatively, metal or metal alloy, or the like.

A component that requires dehydrated air, such as the headspace of the tank of the load tap changer, may be connected to the dehydrating breather200by a connector such as pipe, tube, hose, or the like. When the component exhales, air flows from the component, through the connector, and into the dehydrating breather200, which vents the air to the atmosphere. When the component inhales, air is drawn into the dehydrating breather200and passes through a desiccant, then through the connector to the component. The desiccant dehumidifies the air provided to the component, and, over time, may become saturated with water. The dehydrating breather200may remove the water absorbed by the desiccant using a process called recharging or regeneration.

FIG. 10shows a partial sectional view (X-X) of the dehydrating breather depicted inFIG. 9;FIG. 11shows a partial perspective sectional view (XI-XI) of the dehydrating breather depicted inFIG. 9; andFIG. 12shows a partial exploded view of the dehydrating breather depicted inFIG. 6. During a regeneration cycle, a heating element252, disposed inside the dehydrating breather200may evaporate the water from the desiccant by heating the same. Thereafter, the evaporated water may condensate within the dehydrating breather200and be directed to an outlet290. Portions of the water outlet are heated by the heating element252and accordingly freezing of the water and/or frosting is less likely to occur during cold weather.

The dehydrating breather200may include the lower housing202. The outlet290may include one or more of a thermal coupler210, a thermal conductor220, and a condensate vent230.

During a regeneration cycle, the heating element252, disposed inside the dehydrating breather200may evaporate the water from the desiccant by heating, and a controller may ensure that regeneration occurs only during component exhalation.

The upper housing242may include a slot or vent port256through which air is normally drawn into and expelled from the dehydrating breather200and through a tank port258. A solenoid valve may couple the tank port258to either the desiccant chamber246or the vent port256. During normal operation, the solenoid valve may couple the tank port258to the desiccant chamber246, and the component inhales and exhales through the vent port256and desiccant chamber246. During regeneration, the solenoid valve may couple the tank port258to the vent port256to allow the component to exhale, and energizes the heating element252to evaporate the water absorbed by the desiccant, which condenses on the inner surface of the body240, drains to the lower housing202and passes through the outlet290such as the condensate vent230. If the component attempts to inhale during regeneration, the controller may suspend regeneration and the solenoid valve couples the tank port258to the desiccant chamber246.

The desiccant chamber246may be located in the body240. In one aspect, the desiccant chamber246may include a cylindrical, perforated metal sleeve250that may be centrally located within the body240and may rest upon a screen/filter248located just above the lower housing202. The metal sleeve250and the screen/filter248may form the desiccant chamber246.

The desiccant chamber246may include one or more of the heating element252and a heat distribution fin assembly254. Additionally, the desiccant chamber246may hold the desiccant that may be a silica gel desiccant. However, other types of desiccants are contemplated as well. The silica gel desiccant is not shown in order to simplify the figures herein. However, the silica gel desiccant will fill the voids between the heat distribution fin assembly254and the heating element252that exist in the space located in the metal sleeve250.

In a particular aspect, the outlet290may include the thermal coupler210attached to, or abutting, the bottom of the heating element252and/or the heat distribution fin assembly254in order to conduct thermal energy or heat generated during the regeneration process to the thermal conductor220and, to a lesser extent, condensate vent230. The thermal coupler210may be attached to the thermal conductor220using a threaded or keyed connection, a press fit, or the like. However, other types of physical and mechanical connections are contemplated as well. The thermal coupler210and thermal conductor220may be made from materials with good to excellent thermal conductivity, such as, for example, brass, copper, aluminum, steel, and the like. In one aspect, the thermal coupler210is aluminum and the thermal conductor220is copper. The condensate vent230may be attached to the lower housing202using a threaded connection, and may be made from stainless steel, although other materials are contemplated.

During regeneration, thermal energy or heat flows from the heating element252to the outlet290. This level of heat tends to prevent condensate water flowing through the outlet290from freezing, and, to a lesser extent, to prevent frost or ice from forming on the exterior surfaces of the outlet.

In a particular aspect, thermal energy or heat flows from the heating element252to the thermal conductor220, via the thermal coupler210. This level of heat tends to prevent condensate water flowing through the thermal conductor220and out of the condensate vent230from freezing, and, to a lesser extent, to prevent frost or ice from forming on the exterior surfaces of the condensate vent230.

FIG. 13shows a side view of a thermal conductor according to an aspect of the invention; andFIG. 14shows a top view of the thermal conductor according to the aspect of the invention shown inFIG. 13. In particular,FIGS. 13 and 14present side and top views, respectively, of the thermal coupler210according to an aspect of the invention. The thermal coupler210may include a disk302and a threaded shaft304. The disk302may contact the heating element252or otherwise be in a thermally conductive relationship with the heating element252. Accordingly, the heat generated by the heating element252may be transferred to the thermal coupler210, and more specifically, may be transferred to the disk302. Thereafter, the heat may be transferred to the threaded shaft304. The threaded shaft304may be threaded and may extend downwardly from the disk302. The disk302may include one or more notches306to align with corresponding structure on a bottom of the heating element252. Other constructions of the thermal coupler210, threaded shaft304, and disk302are also contemplated by the invention and are within the spirit and scope of the same.

FIG. 15shows a sectional view (XV-XV ofFIG. 16) and perspective view of a thermal conductor according to an aspect of the invention;FIG. 16shows a sectional view (XVI-XVI) of the thermal conductor according to the aspect of the invention shown inFIG. 15; andFIG. 17shows a perspective view of a thermal conductor according the aspect of the invention shown inFIG. 15. In particular,FIGS. 15,16and17present side and sectional, sectional and perspective views, respectively, of the thermal conductor220according to an aspect of the invention. The thermal conductor220may have a cylindrical upper portion402, a cylindrical lower portion404and a central bore408,412extending therethrough as shown by the dashed lines. The thermal conductor220is also contemplated to have other shaped configurations.

A diameter of the cylindrical upper portion402may be greater than a diameter of the cylindrical lower portion404(as illustrated), or vice versa, or the diameters can be the same. In one aspect, the upper portion of the central bore408may be threaded to receive the threaded shaft304of the thermal coupler210, while the middle and lower portions of the central bore412may be smooth to facilitate condensate water flow. Other arrangements are contemplated as well.

The thermal conductor220may include one or more openings406. The openings406may be circumferentially disposed in the cylindrical upper portion402of the thermal conductor220and may be fluidly coupled to the central bore408,412. These openings406may serve as condensate water inlets and receive the condensate water as it drains from the lower housing202. Although six water inlets are depicted inFIGS. 15,16and17, other quantities of water inlets are also contemplated, such as, for example, two, three, four, eight, etc. An opening410at a bottom of the thermal conductor220may serve as the condensate water exit.

Accordingly, the thermal conductor220may be thermally coupled to the heating element252directly, through the threaded shaft304of the thermal coupler210or the like. The thermal coupling may ensure that the thermal conductor220is transferred heat from heating element252and maintains a temperature above freezing even when the ambient temperature is below freezing. Additionally, the central bore408may be fluidly coupled to the desiccant chamber246via the lower housing202.

FIG. 18is a side view of a vent according to an aspect of the invention;FIG. 19is a bottom view of the vent according to the aspect of the invention shown inFIG. 18; andFIG. 20is a bottom perspective view of the vent according to the aspect of the invention shown inFIG. 18. In particular,FIGS. 18,19and20present side, bottom and bottom perspective views, respectively, of a condensate vent230according to an aspect of the invention. The condensate vent230may include an end cap502. The end cap502may be configured with a hexagonal exterior shape to allow for construction, maintenance, and the like with common tools. However, other shapes are contemplated as well.

The condensate vent230may include a cylindrical threaded shaft504in a central bore extending therethrough as shown by the dashed lines. A screen506may be disposed over a bottom opening of the condensate vent230. The screen506may prevent unwanted objects from entering the condensate vent230. A top opening508may be configured to receive the cylindrical lower portion404of the thermal conductor220including the opening410that forms a water exit. Accordingly, the central bore of the condensate vent230may be fluidly coupled to the opening410that forms a water exit of the thermal conductor220. In another aspect, the thermal conductor220may be attached directly to, or about, the heating element252and/or the heat distribution fin assembly254, and the thermal coupler210is not present. accordingly, the condensate vent230a receipt heat from the heating element252directly or indirectly

FIG. 21shows a schematic diagram of the controller in conjunction with the recharging dehydrating breather of the invention. In particular, the recharging dehydrating breather may include a controller600. The controller600may be located in the upper housing242or elsewhere in electronic communication with the dehydrating breather200. The controller600may be configured on a printed circuit board (PCB) or the like. The controller600may include a microcontroller602and supporting circuitry. The controller600may include a humidity sensor606, a vacuum sensor switch610, and a power supply612.

The controller600may include LED indicators618. The LED indicators618may output various status indications of the controller600or the dehydrating breather200such as power, input/output port operation and the like. The humidity sensor606may sense the relative humidity of the air inhaled by the component604through the desiccant chamber246. The vacuum sensor switch610may sense whether the component is attempting to inhale while coupled to the vent port256during regeneration. Additionally, the controller600may actuate a solenoid valve608. The solenoid valve608in turn may operate a valve614. Other arrangements of the controller600are contemplated and are within the spirit and scope of the invention.