# US 5,700,373 A · Method for sealing a filter

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,700,373 A
- Document ID: US5700373A
- Status: Granted
- Kind: A
- Application number: 08/220,558
- Filed: 1994-03-31
- Granted: 1997-12-23
- Earliest claimed: 1992-09-17
- Assignees: Coors Ceramics Company
- Inventors: Marcus A. Ritland; Dennis W. Readey; Richard N. Kleiner; Jack D. Sibold
- Web page: https://patentgrep.com/patent/US5700373A

## CPC

- B01D 29/111: {Making filtering elements}
- B01D 29/31: Self-supporting filtering elements
- B01D 53/0407: {Constructional details of adsorbing systems}
- B01D 63/061: {Manufacturing thereof}
- B01D 63/066: {with a porous block having membrane coated passages}
- C04B 37/026: {consisting of metals or metal salts}
- C04B 41/009: {characterised by the material treated}
- C04B 41/5127: {Cu, e.g. Cu-CuO eutectic}
- C04B 41/5144: {with a composition mainly composed of one or more of the metals of the iron group}
- C04B 41/52: Multiple coating or impregnating {multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation}
- C04B 41/88: Metals
- C04B 41/89: for obtaining at least two superposed coatings having different compositions
- C22C 1/1015: {by preparing or treating a non-metallic additive preform}
- C22C 1/1036: {starting from a melt}
- C22C 1/1063: {Gas reaction, e.g. lanxide}
- C22C 29/12: based on oxides
- F01L 3/02: Selecting particular materials for valve-members or valve-seats; Valve-members or valve-seats composed of two or more materials
- F01L 3/22: Valve-seats not provided for in preceding subgroups of this group; Fixing of valve-seats
- F02F 3/00: Pistons
- F02F 7/0087: {Ceramic materials}
- H05K 3/4061: {for via connections in inorganic insulating substrates}
- H10W 70/095: {of vias therein}
- H10W 70/611: {for connecting multiple chips together}
- H10W 70/635: {Through-vias}
- B01D 2201/0446: suspended from plates at the upper side of the filter elements
- C04B 2111/00793: {as filters or diaphragms}
- C04B 2237/06: Oxidic interlayers
- C04B 2237/121: based on aluminium
- C04B 2237/122: based on refractory metals
- C04B 2237/123: based on iron group metals, e.g. steel
- C04B 2237/124: based on copper
- C04B 2237/126: wherein the active component for bonding is not the largest fraction of the interlayer
- C04B 2237/127: The active component for bonding being a refractory metal
- C04B 2237/341: Silica or silicates
- C04B 2237/343: Alumina or aluminates
- C04B 2237/346: Titania or titanates
- C04B 2237/348: Zirconia, hafnia, zirconates or hafnates
- C04B 2237/36: Non-oxidic
- C04B 2237/365: Silicon carbide
- C04B 2237/366: Aluminium nitride
- C04B 2237/368: Silicon nitride
- C04B 2237/406: Iron, e.g. steel
- C04B 2237/62: Forming laminates or joined articles comprising holes, channels or other types of openings
- C04B 2237/72: Forming laminates or joined articles comprising at least two interlayers directly next to each other
- C04B 2237/765: at least one member being a tube
- C04B 2237/84: Joining of a first substrate with a second substrate at least partially inside the first substrate, where the bonding area is at the inside of the first substrate, e.g. one tube inside another tube
- F01L 2301/02: Using ceramic materials
- F02B 3/06: with compression ignition (compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02)
- F05C 2201/0415: Zirconium
- F05C 2203/0895: Zirconium oxide
- F05C 2253/16: Fibres
- H05K 1/0306: {Inorganic insulating substrates, e.g. ceramic, glass}
- H05K 2201/0116: Porous, e.g. foam
- H05K 2203/128: Molten metals, e.g. casting thereof, or melting by heating and excluding molten solder
- Y10S 228/903: Metal to nonmetal
- 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)
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- F01L: CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F02F: CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- F05C: INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A process for sealing a ceramic filter by infiltrating a metal into an end of the filter. The process includes the steps of contacting the end of a porous ceramic filter with a molten metal, whereby the metal enters into the ceramic matrix to substantially fill the void space. The ceramic filter is cooled to form a filter having a ceramic-metal composite portion. The present invention also provides a filter having an infiltrated metal seal.

## Claims

### Claim 1

A method for sealing an end of a ceramic filter element, comprising the steps of:
a) providing a porous ceramic filter element comprising a first portion and a second end portion and comprising filtering channels therethrough wherein said filter element comprises a substantially continuous network of open porosity;
b) contacting a portion of said first end of said filter element with a molten metal to infiltrate said metal into the continuous network of open porosity in said first end portion of said filter element without substantially infiltrating said filtering channels;
c) cooling said infiltrated portion to form a filter element having an internally sealed end comprising a ceramic-metal composite portion; and
d) attaching a metal seal ring to said ceramic-metal composite portion.

### Claim 2 (depends on 1)

A method a recited in claim 1, wherein said step of attaching a metal seal ring to said ceramic-metal composite portion comprises the step of brazing said seal ring to said ceramic-metal composite portion.

### Claim 3 (depends on 1)

A method as recited in claim 1, wherein said porous ceramic filter element comprises porous alumina having an open porosity of from about 30 volume percent to about 50 volume percent and said molten metal comprises copper metal.

### Claim 4 (depends on 3)

A method as recited in claim 3 wherein said copper metal comprises an infiltration additive.

### Claim 5 (depends on 4)

A method as recited in claim 4, wherein said infiltration additive is selected from the group consisting of oxygen and titanium.

### Claim 6 (depends on 3)

A method as recited in claim 3, wherein said molten metal comprises copper and from about 1.5 weight percent to about 10 weight percent oxygen.

### Claim 7 (depends on 1)

A method as recited in claim 1, wherein said ceramic filter element comprises a porous ceramic support having from about 30 volume percent to about 50 volume percent open porosity.

### Claim 8 (depends on 7)

A method as recited in claim 7, wherein said porous ceramic support has an average pore size of from about 6 micrometers to about 12 micrometers.

### Claim 9 (depends on 1)

A method as recited in claim 1, further comprising the step of coating at least a portion of said filtering channels with a membrane layer.

### Claim 10

A method for sealing an end of a ceramic-based filter element, comprising the steps of:
(a) placing a metal in a refractory vessel;
(b) heating said metal to a temperature in excess of the melting temperature of said metal such that said metal is in the form of a molten pool having a top surface;
(c) contacting a sintered cylindrical ceramic filter element having a first end and a second end and comprising a plurality of channels therethrough with said top surface of said molten pool for a time sufficient to infiltrate a portion of said sintered ceramic filter element;
(d) removing said sintered ceramic filter element from contact with said molten pool;
(e) cooling said metal-infiltrated portion to form a ceramic filter element having a ceramic-metal composite portion;
(f) attaching a metal seal ring to said ceramic-metal composite portion.

### Claim 11 (depends on 10)

A method as recited in claim 10, wherein said attaching step comprises the step of brazing said seal ring to said ceramic-metal composite with a brazing alloy.

### Claim 12 (depends on 11)

A method as recited in claim 11, wherein said brazing alloy is a copper-silver alloy.

### Claim 13 (depends on 12)

A method as recited in claim 12, wherein said metal seal ring is a stainless steel ring.

### Claim 14

A method for sealing an end of a porous ceramic filter element, comprising the steps of:
(a) providing a porous ceramic filter element having a first end and a second end and comprising a plurality of channels therethrough;
(b) providing a metal seal ring located around a perimeter of said first end of said filter element;
(c) contacting said first end of said ceramic filter element with molten reactive braze metal to infiltrate a portion of said first end with said reactive braze metal; and
(d) cooling said reactive braze metal to form a seal between said filter element and said seal ring.

### Claim 15 (depends on 14)

A method as recited in claim 14, wherein said reactive braze metal comprises titanium.

### Claim 16

A ceramic filter element for a filtration device, comprising:
a) a substantially cylindrical sintered ceramic porous support having channels therethrough;
b) a membrane layer coated on at least a portion of said channels in said porous ceramic support;
c) a metal infiltrated into an end portion of said ceramic filter element to form a ceramic-metal composite portion wherein said ceramic metal composite portion creates a substantially hermetic internal seal within said porous support and wherein said channels are not substantially filled with said metal; and
d) a stainless steel ring attached to said ceramic-metal composite portion.

### Claim 17 (depends on 16)

A filter element as recited in claim 16, wherein said filter element comprises alumina ceramic.

### Claim 18 (depends on 16)

A filter element as recited in claim 16, wherein said filter element has an open porosity of from about 30 volume percent to about 50 volume percent.

### Claim 19

A method for sealing an end of a ceramic filter element, comprising the steps of:
(a) providing a porous ceramic filter element having a first end and a second end and comprising filtering channels therethrough;
(b) contacting a portion of said first end of said filter element with a molten metal to infiltrate said metal into said first end of said filter element;
(c) cooling said infiltrated portion to form a filter element having a sealed end comprising a ceramic-metal composite portion; and
(d) attaching a metal seal ring to said ceramic-metal composite portion.

### Claim 20

A ceramic filter element for a filtration device, comprising:
(a) a sintered ceramic porous support having channels therethrough;
(b) a membrane layer coated on at least a portion of said channels in said porous ceramic support to form a ceramic filter element;
(c) a metal infiltrated into a portion of said ceramic filter element to form a ceramic-metal composite portion; and
(d) a metal ring attached to said ceramic-metal composite portion.

### Claim 21 (depends on 20)

A filter element as recited in claim 20, wherein said metal ring is a stainless steel ring.