# US 9,751,038 B2 · End of service life indicating systems for layered filter cartridges

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- Number: US 9,751,038 B2
- Document ID: US9751038B2
- Status: Granted
- Kind: B2
- Application number: 14/775,812
- Filed: 2014-03-07
- Published: 2016-02-04
- Granted: 2017-09-05
- Earliest claimed: 2013-03-15
- Assignees: 3M Innovative Properties Company
- Applicants: 3M Innovative Properties Company
- Inventors: Kevin A. Frankel; J. Christopher Thomas; Melissa A. Checky; Maria L. Zelinsky; Denise L. Goddard
- Web page: https://patentgrep.com/patent/US9751038B2

## CPC

- B01D 53/0407: {Constructional details of adsorbing systems}
- A62B 9/006: {Indicators or warning devices, e.g. of low pressure, contamination}
- A62B 18/088: {Devices for indicating filter saturation}
- B01D 53/0415: {Beds in cartridges}
- B01D 53/0454: {Controlling adsorption (controlling temperature swing adsorption B01D53/0462, controlling pressure swing adsorption B01D53/047)}
- B01D 2253/102: Carbon
- B01D 2253/104: Alumina
- B01D 2253/106: Silica or silicates
- B01D 2253/108: Zeolites
- B01D 2253/204: Metal organic frameworks (MOF's)
- B01D 2257/2045: Hydrochloric acid
- B01D 2257/2064: Chlorine
- B01D 2257/702: Hydrocarbons
- B01D 2257/7027: Aromatic hydrocarbons
- B01D 2257/708: Volatile organic compounds V.O.C.'s
- B01D 2258/06: Polluted air
- B01D 2259/4146: Contiguous multilayered adsorbents
- B01D 2259/4541: for portable use, e.g. gas masks
- 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)
- A62B: DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING (valves specially adapted for medical use A61M39/00; life-saving devices, apparatus or methods specially adapted for use in water B63C9/00; divers' equipment B63C11/00; specially adopted for use with aircraft, e.g. parachutes, ejector seats, {B64D17/00, B64D25/10}; rescue devices peculiar to mining E21F11/00)

## Abstract

Layered filtered cartridge systems with an End of Service Life Indicating system include a filter cartridge that includes filter media. The filter media includes a multi-layer construction, of a first sorbent layer, a second sorbent layer, and a sensing element adjacent to the first and second sorbent layers such that an indicating element of the sensing element is located at the interface between the first and second sorbent layers. The first sorbent layer has a higher adsorption capacity and/or higher adsorption rate than the second sorbent layer. The sensing element indicates the passage of an adsorption wavefront through the filter cartridge.

## Claims

### Claim 1

A method of filtering contaminants from a gas, comprising:
providing a filter cartridge, the filter cartridge comprising:
a sealed cartridge housing comprising:
a gas inlet;
filter media; and
a gas outlet, wherein the filter media comprises multi-layer construction comprising:
a first sorbent layer;
a second sorbent layer closer in proximity to the gas outlet than the first sorbent layer; wherein the first sorbent layer has a higher adsorption capacity and/or higher adsorption rate than the second sorbent layer; and
a sensing element adjacent to the first and second sorbent layers such that an indicating element of the sensing element is located at the interface between the first and second sorbent layers;
causing gas to flow through the filter cartridge;
detecting a sensing response in the sensing element; and
replacing the filter cartridge.

### Claim 2 (depends on 1)

The method of claim 1, wherein the ratio of A1, the Adsorption Factor for the first sorbent layer, to A2, the Adsorption Factor for the second sorbent layer, is A1/A2 >1, wherein the Adsorption Factor for a sorbent layer is determined from the formula:
A=kv×SL,
wherein A=Adsorption Factor;
kv=effective adsorption rate coefficient (minutes−1); and
SL=Service Life (minutes), the time required to reach 1% breakthrough of a given challenge vapor at standard temperature and pressure.

### Claim 3 (depends on 1)

The method of claim 1, wherein each sorbent layer comprises a sorbent volume, and the volumes of the sorbent layers together form a combined sorbent volume, and the volume of the first sorbent layer is greater than 40% of the combined sorbent volume.

### Claim 4 (depends on 1)

The method of claim 1, wherein the first sorbent layer and the second sorbent layer are substantially discrete layers.

### Claim 5 (depends on 1)

The method of claim 1, wherein the sensing element indicates the passage of the adsorption wavefront through the filter cartridge.

### Claim 6 (depends on 5)

The method of a claim 5, wherein the sensing element comprises a colorimeteric sensing element or an electronic sensing element.

### Claim 7 (depends on 6)

The method of claim 6, wherein detecting a sensing response in the sensing element comprises detecting a color change.

### Claim 8 (depends on 1)

The method of claim 1, wherein the sensing element is located within the filter cartridge at a location such that the sensing element indicates when an adsorption wavefront containing a contaminant reaches the interface between first and the second sorbent layers.

### Claim 9 (depends on 1)

The method of claim 1, wherein the filter cartridge further comprises additional sorbent layers.

### Claim 10 (depends on 1)

The method of claim 1, wherein the contaminants comprise organic vapors, acid gases, basic gases, or a combination thereof.