# US 4,395,333 A · Pre-wet and reinforced molten metal filter

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

- Number: US 4,395,333 A
- Document ID: US4395333A
- Status: Granted
- Kind: A
- Application number: 06/368,107
- Filed: 1982-04-14
- Granted: 1983-07-26
- Earliest claimed: 1982-04-14
- Inventors: Daniel E. Groteke
- Web page: https://patentgrep.com/patent/US4395333A

## CPC

- C22B 9/023: {By filtering (filtration of aluminium C22B21/066)}
- B01D 29/012: {Making filtering elements (making bag, cage, hose, tube, sleeve or like filtering elements B01D29/111)}
- B01D 29/03: self-supporting
- B01D 39/2068: {Other inorganic materials, e.g. ceramics}
- B01D 2201/182: for depth filtration
- Y02P 10/20: Recycling
- Y10T 428/30: Self-sustaining carbon mass or layer with impregnant or other layer
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS
- 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)
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The present invention relates to an improved filter element for use in an apparatus for filtering molten metal, and to the method of making such filter element. The apparatus consists of a filtering vessel fitted with a filter element. In one embodiment of the present invention the improved filter element is pre-wet with metal prior to the filtering apparatus being introduced into service. In a second embodiment of the present invention the improved filter element is reinforced with one or more reinforcing members. The improved filter element can be used in filtering vessels having a variety of designs.

## Claims

### Claim 1

A filter element for insertion into a filtering vessel for filtering molten metal the filter element having reduced start-up time and reduced damage caused as a result of thermal shock, the filter element, comprising:
a porous ceramic body with interconnected pores throughout, said body having a central region bounded by a peripheral edge region;
a refractory cement filling said pores in said peripheral edge region; and
a metal alloy filling the pores of said central region of said porous ceramic body to thereby reduce start-up time and damage to the filter element.

### Claim 2 (depends on 1)

The filter element of claim 1 wherein said pore size is smaller than 17.7 pores per cm (45 pores per in).

### Claim 3 (depends on 2)

The filter element of claim 2 wherein said metal alloy filling the pores of said central region is an aluminum eutectic alloy.

### Claim 4 (depends on 3)

The filter element of claim 3 in which the aluminum eutectic alloy contains 95% zinc-5% aluminum.

### Claim 5 (depends on 3)

The filter element of claim 3 in which the aluminum eutectic alloy is ASTM 413.0.

### Claim 6 (depends on 1)

The filter element of claim 1 which has increased rigidity so as to extend the service life of the filter element when inserted into a filtering vessel for filtering molten metal, said filter element comprising:
a porous ceramic body with interconnected pores throughout having a first section and a second section; and
at least one reinforcing member interposed between said first section and said second section.

### Claim 7 (depends on 6)

The filter element of claim 6 further comprising:
means for attaching said first section to said reinforcing member, and said reinforcing member to said second section.

### Claim 8 (depends on 6, 7)

The filter element of claim 6 or 7 wherein said reinforcing member has passages therethrough which provide communication between said first section and said second section and means for attaching is a refractory cement.

### Claim 9

A method for pre-wetting a filter element for filtering molten metal, the filter element having reduced start-up time and reduced damage caused as a result of thermal shock, the pre-wetting comprising the steps of:
first pre-wetting the filter element with a first metal alloy having a melting point less than a second metal alloy; and
thereafter pre-wetting the filter element with said second metal alloy, said second metal alloy being compatible with the molten metal to be filtered, which thereby reduces start-up time and damage to the filter element.

### Claim 10 (depends on 9)

The method of claim 9 in which said first metal alloy is ASTM 357.0 and said second alloy is ASTM 413.0.

### Claim 11 (depends on 9)

The method of claim 9 further comprising the step of:
pre-washing the peripheral edge of the filter element with a refractory cement before said first pre-wetting step.

### Claim 12 (depends on 11)

The method of claim 11 further comprising the step of:
masking said pre-washed peripheral edge before said first pre-wetting step.

### Claim 13 (depends on 12)

The method of claim 12 wherein the filter element has a pore size of less than 15.7 pores per cm (40 pores per inch), the filter element is used to filter aluminum, said refractory cement is selected from the group consisting of alumina and silica, the metal alloy for said first pre-wetting step is selected from a group of low melting temperature aluminum eutectic alloys, and said second pre-wetting step are selected from a group of eutectic aluminum alloys.