Filter assembly using adhesive center tube

A cylindrical shaped pleated media includes adhesive beads arranged on a periphery to bridge pleats and provide structural support for the pleated media. The pleated media is used in a fluid filter.

BACKGROUND OF THE INVENTION

This invention relates to a filter assembly having a filter element provided by a pleated media. Structural support for the pleated media is provided by an adhesive.

Filter assemblies such as oil filters typically employ a filter element constructed of a pleated media such as paper. The pleated media is arranged in a cylindrical shape. A steel center tube is typically arranged in a central bore defined by the pleated media to provide structural support to the pleated media so that the pleated media does not collapse under fluid pressure. There has been an effort in the filter industry to eliminate as many steel components as possible.

Pleated media is also used in air filter applications. Typically the pleated media is provided in a flat rectangular shape. A perimeter of the pleated media includes a gasket for sealing against a filter housing. A steel screen is typically used on an outlet side of the pleated media to prevent the media from collapsing under the force generated by an air flow through the pleated media. Adhesive beads have been arranged along the pleated media on an inlet side opposite the steel screen to maintain a desired spacing between pleats. An adhesive such as hot melt glue has been used to provide the beads, which bridge the pleats.

It is desirable to eliminate the steel center tube from the filter assembly in, for example, an oil filter.

SUMMARY OF THE INVENTION

The present invention provides a method of manufacturing a center tube-like structure and a filter assembly that uses adhesive beads to provide structural support to a pleated media. The filter assembly includes a housing providing an inlet and an outlet. A filter element, which may be a paper pleated media, is arranged within the housing to separate the inlet from the outlet. The filter element is arranged in a cylindrical shape. An adhesive is arranged on a side of the filter element to provide structural support that prevents the paper pleated media from collapsing under pressure. In one example, the adhesive, which may be a hot melt glue, is arranged on an outlet side within a central bore provided by the filter element.

The filter element is structurally supported by applying adhesive along the filter element to bridge pleats. Opposing ends of the filter element are arranged near one another when arranging the filter element in a cylindrical shape. The adhesive is fully cured once the filter element has been arranged in the cylindrical shape so that the adhesive is rigid, providing adequate structural support under fluid pressure. Multiple adhesive beads may be used or one or more beads may be laid in a zigzag pattern.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A filter assembly10, specifically, an oil filter is shown inFIG. 1. The filter assembly10includes a housing12having a can14providing a cavity. A tapping plate16is arranged at an open end of the can14and is secured by a top plate22to the can14. The tapping plate16provides an inlet18, which is typically provided by multiple holes, and an outlet20, which is typically provided by a threaded central aperture.

A filter element24is mounted between a pair of end caps26. A guide spring28engages one of the end caps26and biases the filter element24to a desired location within the housing12. The filter element24is arranged between the inlet18and outlet20so that fluid flowing through the filter assembly10must pass through the filter element24before exiting the outlet20. A bypass valve30may be arranged between one of end caps26and the housing12. The bypass valve30permits the fluid to circumvent the filter element24when the filter element24becomes clogged.

The filter element24is typically provided by a pleated media27arranged in a cylindrical shape. The pleated media27includes an inlet side23at an outer periphery and an outlet side25arranged at an inner periphery of the pleated media27where the filter element24provides a central bore.

The pleated media27includes an inner periphery33providing ridges31formed by the pleats of the pleated media27. Beads of adhesive32are arranged at the inner periphery33to bridge the ridges31as shown inFIG. 3. The adhesive32is rigid when fully cured and is sufficient in its cured state to provide desired structural support during normal operation of the filter assembly10.

Clips34may be used to secure opposing ends36of the filter media27when arranging the filter media27into a cylindrical shape. Alternatively, adhesive51may be used to secure the opposing ends36, as shown inFIG. 3.

A method of providing the adhesive reinforced filter media27is shown generally at38inFIG. 2. Typically, a roll of paper filter media40is provided. The paper filter media40is fed to a pleater42to provide pleated media43having ridges31. The pleated media43is passed under multiple adhesive dispensers44having heads46that dispense beads of adhesive48across the ridges31. In one example, a hot melt glue is used as the adhesive32. It is desirable that the adhesive32in its uncured state is sufficiently viscous so as to not flow into the pleated media43, which would minimize the usable surface area of the pleated media. The pleated media43is manipulated to form the pleated media43into a cylindrical shaped media50prior to the beads of adhesive48fully curing.

Referring toFIG. 3, opposing ends36are arranged near one another to provide the cylindrical shape. The opposing ends36may be joined to one another by clips34, as shown inFIG. 1, or by applying adhesive51to glue the opposing ends36to one another.

It may be desirable to arrange the ends of the cylindrical shaped media50relative to the opposing end caps26. Typically the ends of the cylindrical shaped media50are embedded in a plastisol or other adhesive dispensed on the end caps26. The cylindrical shaped media50, with its beads of adhesive48, is permitted to cure. In the case of hot melt glue, the beads of adhesive48are permitted to cool to cure the glue which provides a rigid bead. The cylindrical shaped media50is processed along with other components to provide a filter assembly52, as shown inFIG. 2.