BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of an embodiment of a refrigerant system of the present invention, including a liquid refrigerant filter of the present invention.
FIG. 2 is a cross-sectional view of a first embodiment of the filter of FIG. 1 in accordance with the present invention.
FIG. 3 is a cross-sectional view of a second embodiment of a liquid refrigerant filter in accordance with the present invention.
FIG. 4 is a cross-sectional view of a third embodiment of a liquid refrigerant filter in accordance with the present invention.
Whenever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates a closed loop refrigerant system 100 employing a liquid refrigerant filter of the present invention in a first embodiment. As shown in FIG. 1, the high-pressure side of the refrigerant loop includes a compressor 10 that is provided to compress refrigerant vapor. The high-pressure compressed refrigerant vapor is conveyed to a condenser 12 within the high-pressure side of the refrigerant loop. The condensed liquid refrigerant from the condenser 12 is then conveyed to a filter 14, also located within the high-pressure side of the refrigerant loop.
As shown in FIGS. 2-4, the filter 14 is an in-line filter that includes a filter element 30 selected to permit adequate flow of liquid refrigerant from the filter 14 to a downstream expansion device 16, while effectively removing any solid or semi-solid contaminants. The filter element 30 preferably also includes a drying element for removing water and moisture from the liquid refrigerant.
The system 100 further includes a system to cool the liquid refrigerant to solidify otherwise soluble contaminants, which solidified contaminants are then captured, or adsorbed by, the filter element 30 of the filter 14. For example, in the first embodiment of the system 100 shown in FIGS. 1-2, the system for cooling the filter 14 includes a refrigerant coil 18 containing expanded refrigerant sourced from downstream of the expansion device 16. Thus, the refrigerant in the refrigerant coil 18 is cooler than the liquid refrigerant flowing into the filter 14 from the condenser 12. The refrigerant coil 18 is in thermal contact with the liquid refrigerant flowing through the filter 14 from the condenser 12, thereby cooling the liquid refrigerant in the filter 14. The amount of cooling provided by the refrigerant coil 18 to the refrigerant liquid within the filter 14 is sufficient to cause contaminants in the refrigerant liquid to precipitate out of solution and be captured by the filter element of the filter 14. For example, the amount of cooling may be determined by the liquidus-solidus transition temperature, or by a solubility index, for a known contaminant in a selected high temperature/high pressure liquid refrigerant. For example, the refrigerant may be any known refrigerant, but is preferably R-134a, R-407C, R410A, and combinations thereof. The contaminant to be removed can be any known contaminant, but is preferably selected from water, acids, inorganic chlorides, inorganic fluorides, dirt, water, sludge, wax, clathrate hydrates, and combinations thereof. The amount of cooling accomplished to precipitate contaminants can be adjusted by varying various parameters such as the volume of the filter 14, the filter flow rate, the volume and flow rates in the refrigerant coil 18, thermal efficiency of the thermal contact between the coil 18 and the filter 14, the selection of refrigerant, and combinations thereof.
In the system of FIG. 1, throttled refrigerant is passed a coil 18 to cool the liquid refrigerant contents of the filter 14, thereby aiding in the precipitation and removal of otherwise soluble contaminants from the liquid refrigerant. The amount of cooling accomplished to precipitate contaminants can be adjusted by varying various parameters such as the volume of the filter 14 filter flow rate, volume and flow rate in the refrigerant coil 18, thermal efficiency of the thermal contact between the coil 18 and the filter 14, and the selection of refrigerant, and combinations thereof.
As shown in FIG. 2, in a first embodiment, the filter 14 includes a primary chamber 22 surrounded by a sidewall 15 that forms an outer housing of the filter. The primary chamber is communicably connected to an upstream condenser 12 and to a downstream expansion device 16. In this embodiment, a refrigerant coil 18 is communicably connected to the outlet of the expansion device 16. The refrigerant coil 18 is disposed in contact with, or in close proximity to the outside of the sidewall 15 so as to render thermal contact between the expanded refrigerant in the coil 18 and the liquid refrigerant in the primary chamber 22 of the filter 14.
In a second embodiment shown in FIG. 3, the system for cooling the refrigerant liquid in the filter 14 includes a filter 14 and expansion device 16 combined within a single unit. As shown in FIG. 3, the filter 14 includes a primary chamber 22 that is communicably connected to the high-pressure liquid refrigerant line from the condenser 12 for receiving high-pressure liquid refrigerant. The primary chamber 22 includes a filter element 30 for capturing solid and semi-solid contaminants. The primary chamber 22 includes a sidewall 23 that separates the primary chamber from a secondary chamber 26. The sidewall 23 is impermeable to gas and liquid, but includes an exit passageway 24 that permits filtered liquid refrigerant to pass to an expansion device 16 contained within the filter 14. Refrigerant passing through the expansion device 16 flashes to yield cooled refrigerant gas and liquid. The cooled refrigerant gas and liquid circulates within the secondary chamber 26, and is contained within the filter 14 by the filter sidewall 15. Because the sidewall 23 is comprised of material that permits thermal transfer, thermal transfer occurs between high-pressure liquid refrigerant in the primary chamber 22 and expanded liquid-gaseous refrigerant in the secondary chamber 26. In other words, circulation of expanded refrigerant gas and liquid with the secondary chamber 26 cools the sidewall 23 of the primary chamber 22, thereby cooling hot refrigerant gas within the chamber 22. As previously described, cooling of the hot liquid refrigerant within the primary chamber 22 causes otherwise soluble contaminants to precipitate out of the refrigerant as solids or semi-solids, which are then captured by the filter element 30. The filter sidewall 15 further includes a communicable connection 28 to permit the expanded refrigerant to pass to downstream components such as additional expansion devices, the evaporator 20, and eventually to the compressor 10. The filter 14 may optionally further include features to promote desired thermal transfer by efficient circulation of the expanded refrigerant within the secondary chamber 26. For example, as shown in FIG. 3, one or more baffles 32 may be provided to deflect and redirect expanded gas leaving the expansion device 16 so that the refrigerant circulates before escaping through connection 28.
In an alternative embodiment of the filter shown in FIG. 4, the expansion device 16 is connected to a refrigerant line 18 that is coiled throughout the secondary chamber 26 in close proximity to the sidewall 23 of the primary chamber 22. In this alternative embodiment, the coil 18 is contained by the sidewall 15 of the filter 14, save for a communicable connection 28 through the sidewall 15 that permits the coil 18 to be connected to downstream components such as the evaporator 20.
The filter 14 in one example filters and removes both insoluble contaminants such as dirt, as well as otherwise soluble contaminants from the hot liquid refrigerant received from the condenser, and preferably as early as possible before the contaminates can reach the expansion device 16 of the system 100. Known liquid refrigerant filter elements 30 can be provided in combination with the means for cooling the refrigerant liquid, thereby removing insoluble as well as otherwise soluble contaminants precipitated by the cooling process previously described herein.
Optionally, pressure gauges are provided both upstream and downstream of the filter 14, respectively, to provide a continuous indication of the pressure drop across the filter 14. Providing such pressure gauges may assist in determining when a new filter element 30 is required, thereby avoiding a clogged filter 14 that would compromise system performance.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
Patent Application
20070277536
