Gas separation: processes – Solid sorption – Inorganic gas or liquid particle sorbed
Reexamination Certificate
2002-09-06
2004-09-28
Lawrence, Frank M. (Department: 1724)
Gas separation: processes
Solid sorption
Inorganic gas or liquid particle sorbed
C055S417000, C055S420000, C055S515000, C096S134000
Reexamination Certificate
active
06797037
ABSTRACT:
FIELD OF THE INVENTION
This invention pertains generally to dehydrators for removing moisture from air. More particularly, the present invention is directed to dehydrating breathers for power devices.
BACKGROUND OF THE INVENTION
High power electrical equipment, such as large electrical transformers, load tap changers, and circuit breakers, are typically immersed in oil, which is utilized to insulate and cool the power devices. Because the oil expands and contracts with temperature changes, such equipment is provided with a head space above the oil that is vented to the atmosphere to control pressure in, for example, a transformer tank. The pressure in the tank has to be maintained such that air bubbles, which can decrease the dielectric strength of the oil, are inhibited from developing in the oil.
When the heat in the tank increases, the oil in the tank expands, the pressure in the tank increases, and air in the reservoir is forced from the tank. When the tank begins to cool down, the oil in the tank contracts, the pressure in the tank decreases, and air is drawn into the tank to maintain the pressure in the tank.
A dehydrator breather is conventionally utilized to regulate airflow into and out of the tank. In some dehydrating breathers, a vent is provided between the vessel and the outside air. A valve is positioned between the vent and dehydrator breather container that controls the pressure in the tank by opening and closing, as necessary, to control air flow into and out of the tank.
Often, the dehydrator breather includes a desiccant material, such as a silica gel, to remove any moisture from the air before it is allowed into the tank. Water is a conductor, and thus, moisture entering the tank has the capability of destroying the electrical properties of the transformer.
Problems arise, however, when the desiccant escapes the desiccant container. For example, during shipment, the desiccant may break into fine pieces that escape the desiccant container. In addition, desiccant particles may pass through the valve with air that is exiting the dehydrator breather, and become trapped in the valve and/or trapped on top of the vent.
Further, moisture, which evaporates from the drying of the desiccant, often forms condensation on the walls of the dehydrator breather. When the condensation returns to a liquid state, it flows through the valve and out to the atmosphere via the holes in the vent. However, if the desiccant particles are trapped in the valve or clogging the vent, the moisture may become trapped in the vessel and the desiccant may be unable to dry out completely. As a result, the dehydrating breather will not be able to perform its drying functions.
Accordingly, it would be desirable to provide a dehydrator breather that does not allow desiccant particles, which may escape the desiccant container, from disturbing the operation of the dehydrator.
SUMMARY OF THE INVENTION
In one aspect of the present invention, a dehydrator breather is provided that includes a vessel, a valve housing coupled to the vessel, and a vent assembly coupled to the valve housing. The vent assembly includes a vent assembly body, and at least one screened port. The screened port is disposed along a vertical axis of the vent assembly body.
In another aspect of the present invention, a dehydrator breather is provided that includes a vessel, a desiccant container positioned within the vessel, a valve housing, coupled to the vessel, and a filter positioned between the desiccant container and the valve housing.
In another aspect of the present invention, a dehydrator breather is provided that includes a means for regulating air flow through the vessel, a means for removing moisture from air that passes through the regulating means, a means for retaining the moisture removing means within the vessel, and a means for preventing the moisture removing means from interfering with operation of the regulating means. The preventing means is positioned between the returning means and the regulating means.
In another aspect of the present invention, a method for operating a dehydrator breather is provided that includes regulating air through the dehydrator breather utilizing a valve housing, removing moisture from the air utilizing a desiccant, retaining the desiccant in a desiccant container and capturing any desiccant that passes through the desiccant container utilizing a vent assembly. The vent assembly includes a vent body, and at least one screened port positioned on a surface of the vent body.
In yet another aspect of the present invention, a dehydrating breather is provided that includes a vessel, a valve housing coupled to the vessel. The valve housing includes a valve seat formed integrally with the valve housing.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
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patent: 5902381 (1999-05-01), Golner et al.
patent: 6071321 (2000-06-01), Trapp et al.
patent: 6235192 (2001-05-01), Melfi et al.
Golner Thomas M.
Mehta Shirish P.
Baker & Hostetler LLP
Lawrence Frank M.
Waukesha Electric Systems Incorporated
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