# US 2012/0006734 A1 · Filter with expandable end cap facilitating easier change-out

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- Number: US 2012/0006734 A1
- Document ID: US20120006734A1
- Status: Published application
- Kind: A1
- Application number: 12/832,287
- Filed: 2010-07-08
- Published: 2012-01-12
- Earliest claimed: 2010-07-08
- Assignees: Hoff Engineering Company, Inc.
- Inventors: Daniel E. Argue; E. Michael Doyle; Edward M. Doyle
- Web page: https://patentgrep.com/patent/US20120006734A1

## CPC

- B01D 29/96: in which the filtering elements are moved between filtering operations; Particular measures for removing or replacing the filtering elements; Transport systems for filters (B01D29/09, B01D29/70 take precedence)
- B01D 29/232: {with corrugated, folded or wound sheets}
- B01D 2201/0415: Details of supporting structures
- B01D 2201/291: End caps
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)

## Abstract

An improved filter arrangement solves problems associated with dislodging the filter from a support basket at change-out when intimate contact between the filter and basket is no longer desirable. An elastomeric end cap is bonded to the distal end of the filtering medium. The end cap has a circular, outer perimeter defining a diameter less than the inner diameter of the filter basket. The end cap is dome shaped, such that when the filtering element is inserted into the filter basket with the end cap positioned adjacent the bottom of the filter basket, the end cap assumes a pressurized state when a fluid entering the filtering element applies pressure to the end cap, causing the outer perimeter of the end cap to expand radially outwardly, and a non-pressurized state wherein the outer perimeter of the end cap contracts, facilitating an easier removal of the element from the basket.

## Claims

### Claim 1

A replaceable filter element configured to be received by a cylindrical, perforated filter basket having an inner wall and a circular bottom with a diameter, D, the filter comprising:
a cylindrical filtering medium having proximal and distal end defining a length and a lengthwise hollow bore enabling a fluid to be filtered to enter into the hollow bore and pass through the medium from the inside out;
an elastomeric end cap bonded to the distal end of the filtering medium, the end cap having a circular, outer perimeter defining a diameter D′ less than D; and
the end cap further being dome shaped, such that when the filtering element is inserted into the filter basket with the end cap positioned adjacent the bottom of the filter basket, the end cap assumes a pressurized state when a fluid entering the filtering element applies pressure to the end cap, causing the outer perimeter of the end cap to expand radially outwardly from D′ to D, and a non-pressurized state wherein the outer perimeter of the end cap returns to D′, facilitating an easier removal of the element from the basket.

### Claim 2 (depends on 1)

The replaceable filter element of claim 1, wherein the filter medium is pleated.

### Claim 3 (depends on 1)

The replaceable filter element of claim 1, wherein the filter medium is a non-pleated tube.

### Claim 4 (depends on 1)

The replaceable filter element of claim 1, wherein the dome shape is formed in a central area of the end cap surrounded by a flat, annular ring to which the distal end of the filtering medium is attached.

### Claim 5 (depends on 1)

The replaceable filter element of claim 1 wherein, in the pressurized state, at least a distal portion of the filtering medium also expands radially outwardly toward and against the inner wall of the filter basket and wherein, in the non-pressurized state at least a distal portion of the filtering medium also contracts radially inwardly away from the inner wall of the filter basket.

### Claim 6 (depends on 1)

The replaceable filter element of claim 1, wherein:
the bottom of the filter basket is substantially flat;
the end cap includes a convex surface oriented toward the proximal end of the filtering element and a concave surface oriented toward the distal end of the filtering medium; and
in the pressurized state, the concave surface of the end cap flattens out against the bottom of the filter basket.

### Claim 7 (depends on 1)

The replaceable filter element of claim 1, wherein:
the bottom of the filter basket includes a concave surface;
the end cap includes a convex surface oriented toward the distal end of the filtering; and
in the pressurized state, the convex surface of the end cap conforms against the concave surface of the filter basket.