Horizontal filter stage with simultaneous venting and draining

A filter assembly for filtering particulate contaminants from a fluid comprises: a generally cylindrical filter unit with one end closed and the other end open; a filter head comprising a generally cylindrical sleeve extending generally horizontally an open end for receiving the open end of the filter unit with that has a vent port aligned with a vertical axis through an upper portion of the sleeve and a drain port aligned with the vertical axis extending through a lower portion of the sleeve; and a coupling for securing the open end of the filter unit to the filter head to seal the sleeve vent and drain ports; wherein loosening the coupling allows the filter unit to slide away from the filter head sufficiently to establish fluid communication between the sleeve vent and drain ports.

FIELD OF THE INVENTION

The invention relates to fluid supply and distribution systems, and more particularly to filtering assemblies for fluid distribution systems.

BACKGROUND OF THE INVENTION

Fluid distribution systems for aerospace applications, such as fuel or lubrication oil supply and distribution systems, generally require a filtration stage to remove particulate contaminants from the fluid. Because of space limitations, it is common for the filtration stage to comprise a filter assembly integrated with a fluid delivery pump. Such a filter assembly comprises a filter head attached to the pump and a removable filter unit that attaches to the filter head. The removable filter unit generally comprises a filter bowl and a disposable filter element therein.

Particularly in aerospace applications, it is often desirable for the filter unit to mount to the filter head in a horizontal orientation due to space constraints. Unfortunately, removal of the filter unit from the filter head then results in spillage of fluid remaining in the filter unit or draining from the filter head.

SUMMARY OF THE INVENTION

The invention generally comprises a filter assembly for filtering particulate contaminants from a fluid comprising: a generally cylindrical filter unit with one end closed and the other end open with a generally circular first fluid port and a generally annular second fluid port in a coaxial arrangement; a filter head comprising a generally circular fluid interface aligned along a generally horizontal axis with a generally circular first fluid port and a generally annular second fluid port in a coaxial arrangement to mate with the corresponding filter unit first and second fluid ports and further comprising a generally cylindrical sleeve extending generally horizontally from the interface with an open end for receiving the open end of the filter unit with a vent port aligned with a vertical axis horizontally displaced from the interface extending through an upper portion of the sleeve and a drain port aligned with the vertical axis extending through a lower portion of the sleeve; and a coupling for securing the open end of the filter unit to the filter head interface to seal the sleeve vent and drain ports and mate the corresponding first and second fluid ports of the filter unit and filter head to establish fluid communication between them; wherein loosening the coupling allows the filter unit to slide away from the filter head interface sufficiently to establish fluid communication between the sleeve vent and drain ports and the fluid ports in the filter unit and filter head.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a cut-away side view of a filter assembly2according to a possible embodiment of the invention. The filter assembly2comprises a generally cylindrical filter unit4and a filter head6aligned along a generally horizontal axis8. The filter unit4may comprise a filter bowl10with one end closed and the other end open. The filter unit4may also comprise a generally cylindrical filter element12that mounts in the filter bowl10. The open end of the filter unit4has a generally circular first fluid port14and a generally annular second fluid port16in coaxial alignment with the horizontal axis8.

The filter element12may be a replaceable and disposable element that the filter bowl10receives through its open end. The filter unit first fluid port14may comprise an axial void within the filter element12. The filter unit second fluid port16may comprise a cylindrical void between the filter element12and the filter bowl10. The filter element12engages an annular bowl flange18within the closed end of the filter bowl10to seal the filter element12to the closed end of the filter bowl10. A packing seal or gasket20, such as an O-ring, may facilitate sealing of the filter element12to the closed end of the filter bowl10. Multiple protrusions22along an inner surface24of the filter bowl10proximate its open end may facilitate alignment of the filter element12and prevent rotation of the filter element12within the filter bowl10.

The filter head6comprises a generally circular filter head fluid interface26with a generally circular first fluid port28and a generally annular second fluid port30in coaxial alignment with the horizontal axis8. The filter head first fluid port28mates with the filter unit first fluid port14and the filter head second fluid port30mates with the filter unit second fluid port16. The filter element12engages an annular interface flange32that protrudes from the interface26to seal the filter head first fluid port28to the filter unit first fluid port14. A packing seal or gasket34, such as an O-ring, may facilitate sealing of the filter head first fluid port28to the filter unit first fluid port14.

The filter head6also comprises a generally cylindrical sleeve36that extends generally horizontally from the interface26with an open end that receives the open end of the filter unit4. The sleeve36comprises a vent port38aligned with a vertical axis40that is horizontally displaced from the interface26that extends through an upper portion of the sleeve36from its outer surface37to its inner surface39and a drain port42aligned with the vertical axis that extends through a lower portion of the sleeve36from its outer surface37to its inner surface39. An annular packing seal44proximate the open end of the filter unit4horizontally positioned between the interface26on one side and the filter head sleeve vent port38and drain port42on the other may seal these ports from the open end of the filter unit4as well as sealing the entire filter assembly2.

The filter assembly2also comprises a coupling46for securing the open end of the filter unit4to the filter head6to seal the sleeve vent port38and the sleeve drain port42as well as sealing the entire filter assembly2and mate the filter unit first fluid port14to the filter head first fluid port28and the filter unit second fluid port16to the filter head second fluid port30. The coupling46may comprise a threaded section48on a portion of the filter unit4that mates with a threaded section50on a portion of the filter head sleeve36, with these threaded sections horizontally positioned between the vent port38and drain port42on one side and the open end of the sleeve36on the other side. An annular scraping seal52between the filter unit4and the filter head sleeve36horizontally positioned between the vent port38and the drain port42on one side and the filter unit threaded section48and the sleeve threaded section50on the other side may reduce fluid and fluid contaminants from entering these threaded sections upon fluid drainage and removal of the filter unit4from the filter head6.

Alternatively, the coupling46may comprise an annular flange54on the filter unit4that engages the open end of the filter head sleeve36, a threaded section56of the sleeve adjacent its open end and a threaded coupling nut, sleeve or ring58that engages the filter unit flange54and mates with the threaded sleeve section56to secure the open end of the filter unit4to the filter head6. In this case, since the threads of the threaded sleeve section56and coupling ring58are external, the annular scraping seal52may be optional. Further, the coupling46may be a bolted flange, retaining ring, flange clamp, or any other such coupling device.

FIG. 2is a cut-away side view of the filter assembly2according to a possible embodiment of the invention with its filter unit4in a partially withdrawn or draining position from the filter head6for fluid drainage. Loosening the coupling46allows the filter unit4to slide away from the filter head6sufficiently to establish fluid communication between the sleeve vent port38, the sleeve drain port42, the filter unit first fluid port14, the filter unit second fluid port16, the filter head first fluid port28, the filter head second fluid port30, and most cavities within the filter head6and the filter unit4. This operation allows venting and draining in a single operation and may provide for remote fluid drainage collection. The vent port38may be useful for both venting and flushing purposes. Arrows60show the possible fluid flow path in this draining position. The vent port38may terminate at the top of the sleeve36or it may wrap around the filter head6and terminate at the drain port42to collect any fluid drainage from the vent port38as well. After complete draining of fluid from the vent port38and drain port42, the complete removal of the filter unit4from the filter head6is possible with no fluid spillage.

The described embodiments of the invention are only some illustrative implementations of the invention wherein changes and substitutions of the various parts and arrangement thereof are within the scope of the invention as set forth in the attached claims.