Liquid purification or separation – With repair or assembling means
Reexamination Certificate
2002-12-09
2004-09-07
Lithgow, Thomas M. (Department: 1724)
Liquid purification or separation
With repair or assembling means
C210S411000, C210S493100, C210S493500, C055S498000, C055S521000, C055SDIG005, C264S271100, C264S279000, C264SDIG004
Reexamination Certificate
active
06787031
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates generally to a filter cartridge. In particular, the present invention relates to a retention strap for the filter cartridge and method of manufacturing the filter cartridge with the retention strap.
2. Description of the Prior Art
Filter cartridges that have pleated filtration media for filtering particulates from a particulate laden fluid stream moving in one direction through the filter cartridge are known. Such a filter cartridge is often subjected to cleaning fluid pulses moving for short periods of time through the filtration media in a direction opposite to the direction that the particulate laden fluid stream moves. Such a filter cartridge is referred to as a “pulse pleat” filter cartridge. Known retention straps encircle portions of the pulse pleat filter cartridge to prevent the filtration media from excessive movement during exposure to the cleaning fluid pulses.
However, the known retention straps for pulse pleat filter cartridges have drawbacks because they are difficult to install onto a filter cartridge and may not remain in the relative axial location they are initially placed in. For example, a known textile retention strap must be manually wrapped about the filtration media of the filter cartridge. The textile retention strap is typically tightened manually and the ends of the retention strap are overlapped. The ends of the retention strap are then adhered or fastened together while a desired tension is manually maintained on the retention strap.
It is important that the retention strap remain in a desired relative axial location along the filter cartridge to assure that the strap properly protect the filtration media from excessive movement during exposure to the cleaning fluid pulses. This is typically accomplished by the use of an adhesive. However, such an adhesive axial location device has been known to fail and the strap may become incorrectly positioned axially along the filter cartridge.
SUMMARY OF THE INVENTION
The present invention is directed to a filter cartridge for removing particulates from a particulate laden fluid stream moving one direction through the filter cartridge. The filter cartridge is periodically subjected to cleaning fluid moving in an opposite direction to the direction the particulate laden fluid stream moves. The filter cartridge comprises filtration media having a plurality of pleats. The filtration media is formed into a tubular configuration and has a plurality of circumferentially spaced apart pleats. Mounting structure is at a first axial end portion of the filtration media. An end cap is at a second axially opposite end portion of the filtration media. The filtration media is maintained in the generally tubular configuration by the mounting structure and the end cap. A retention device limits radial movement of the filtration media when subjected to the periodic cleaning fluid and maintains adjacent pleats in the filtration media circumferentially spaced apart.
The retention device comprises a thermoplastic elastomer material capable of withstanding the elevated operating temperatures and operating environment that the filter cartridge is exposed to. The retention device is attached to the filtration media. Each of the pleats of the filtration media has a tip and a pair of sides extending from the tip. The retention device engages and is adhered to at least one of the tips and sides of pleats of the filtration media. The retention device is applied to the filter cartridge during an extrusion operation. The retention device further includes reinforcement structure.
The present invention is also directed to a method of making the filter cartridge. The method comprises the steps of providing filtration media formed into a tubular configuration and having a plurality of circumferentially spaced apart pleats. Mounting structure is provided at a first axial end portion of the filtration media and an end cap at a second axially opposite end portion of the filtration media to maintain the filtration media in the generally tubular configuration. A retention device is applied to limit radial movement of the filtration media in the opposite direction when subjected to the periodical cleaning fluid and to maintain the pleats in the filtration media circumferentially spaced apart.
The retention device applying step further includes the step of providing a thermoplastic elastomeric material capable of withstanding the elevated operating temperatures and operating environment that the filter cartridge is exposed to. Each of the pleats of the filtration media has a tip and a pair of sides extending from the tip. The method also includes attaching the retention device to the filtration media. The retention device applying step further includes providing a retention device that engages at least one of the tips and sides of pleats of the filtration media. The retention device applying step further includes the step of extruding the retention device onto the filter cartridge. The extruding step further comprises the step of holding and rotating the filter cartridge while applying the retention device directly onto the filter cartridge. The retention device applying step further includes the step of providing reinforcing structure in the retention device. The providing reinforcing structure step further includes the step of extruding the retention device on to the filter cartridge. The method also includes the step of deforming a portion of the retention device between adjacent pleats.
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Carothers Charles Grant
Van Pelt Randall David
BHA Group Holdings, Inc.
Blackwell Sanders Peper Martin LLP
Lithgow Thomas M.
Strugalski Greg
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