US20220055096A1

US20220055096A1 - Pour Cup with Filter Lock

Info

Publication number: US20220055096A1
Application number: US17/403,332
Authority: US
Inventors: Matthew W. Willer; Kevin E. Keyzer
Original assignee: Porvair PLC
Current assignee: Porvair PLC
Priority date: 2020-08-21
Filing date: 2021-08-16
Publication date: 2022-02-24

Abstract

An improved filtration system is provided. The filtration system comprises a pour cup comprising a reservoir and a filter engagement region wherein the filter engagement region comprises a pour cup taper, tab slots and a bottom. The filtration system also comprises a filter wherein the filter comprises a filter taper and filter tabs wherein the filter tabs can be received by the tab slots in one rotational orientation of the filter relative to the pour cup and the tab slots engage with the bottom in a second rotational orientation of the filter relative to the pour cup.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention claims priority to pending U.S. Provisional Patent Application No. 63/068,500 filed Aug. 21, 2020 which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention is related to a pour cup for introducing molten material into a mold wherein the pour cup comprises a filter capable of locking into the pour cup.

BACKGROUND

It has been a long-standing practice to filter molten metals and alloys prior to introduction of the molten metal or alloy into a mold. The filter removes unwanted impurities thereby increasing the quality of the molded product either from an elemental analysis perspective or a crystallinity perspective.
As readily realized to those of skill in the art, pouring a molten metal is dangerous and difficult. The metal is obviously at a very high temperature, the molten metal is heavy and the operation must be done expeditiously to avoid refreezing of the metal during the process of pouring, filtering and filling of the mold. It has been a long-standing practice to utilize a pour cup, also referred to as a mold cup, wherein the pour cup functions as a funnel to provide a large area within which to pour the molten metal. The cross-section of the pour cup decreases from top to bottom.
It has long been the desire of skilled artisans to filter the molten metal at the pour cup. The pour cup provides a larger cross-sectional area to accommodate the pouring metal and filtration at the pour cup is the earliest opportunity for filtration. Unfortunately, the practice of filtering in the pour cup has been difficult to accomplish for multiple reasons.
The pour cup and filter must be capable of receiving a large volume of molten metal. In an effort to avoid breakage, due to differences in coefficients of thermal expansion, it is necessary to heat up the pour cup and filter prior to initiation of the pour. This is typically done by heating the pour cup large side down to facilitate quick removal from the furnace and engagement with the mold system. The additional step of adding a hot filter after placement of the pour cup has proven difficult and is typically avoided.
Yet another problem, when a filter is used, is that the large volume of molten metal tends to dislodge the filter from the pour cup thereby rendering the filter useless. Some artisans have attempted to utilize a gasket however, this complicates efforts to match the filter with the pour cup since the volume occupied by the gasket must be considered. Furthermore, the gasket has a different coefficient of thermal expansion than the filter or pour cup which further complicates efforts to have a suitable seal.
The present invention provides a pour cup with a filter wherein the filter can be mated with the pour cup prior to heating thereby eliminating the necessity of separate handling of the heated pour cup and filter. The instant invention also eliminates the necessity of a gasket.

SUMMARY OF THE INVENTION

The present invention is related to a pour cup with a filter wherein the filter is locked to the pour cup, preferably, prior to heating of the pour cup.
More specifically, the present invention is related to an interlocking pour cup and filter for use in the filtration of molten metal.
A particular feature is the ability to form the pour cup and filter separately.
These and other embodiments, as will be realized, are provided in a filtration system. The filtration system comprises a pour cup comprising a reservoir and a filter engagement region wherein the filter engagement region comprises a pour cup taper, tab slots and a bottom. The filtration system also comprises a filter wherein the filter comprises a filter taper and filter tabs wherein the filter tabs can be received by the tab slots in one rotational orientation of the filter relative to the pour cup and the tab slots engage with the bottom in a second rotational orientation of the filter relative to the pour cup.
Yet another embodiments is provided in a method for assembly a filter assembly comprising:
positioning a pour cup comprising a reservoir and a filter engagement region wherein the filter engagement region comprises a pour cup taper, tab slots and a bottom; and orienting a filter relative to the pour cup wherein the filter comprises a filter taper and filter tabs wherein the filter tabs are aligned with the tab slots;
inserting the filter through the reservoir to a position wherein the filter tabs are received by the tab slots; and
rotating the filter relative to the pour cup wherein the tab slots are not aligned with the tab slots and the filter tabs are engaged with the bottom.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional schematic view of an embodiment of the invention.

FIG. 2 is a cross-sectional schematic view of an embodiment of a pour coup.

FIG. 3 is a schematic side view of an embodiment of a filter.

FIG. 4 is a partially cut-away bottom schematic view of an embodiment of the invention.

FIG. 5 is a cross-sectional schematic perspective view of an embodiment of a pour coup.

FIG. 6 is a cross-sectional schematic view of an embodiment of the invention.

FIG. 7 is a cross-sectional schematic perspective view of an embodiment of a filter.

DESCRIPTION

The present invention is related to a pour cup for molten metal with a filter, preferably a matrix filter, capable of being reversibly locked in the pour cup.
The pour cup comprises tab slots which reversibly engage with the filter. In use the filter is inserted into the pour cup with the filter tabs and tab slots aligned thereby allowing the filter body to fully seat within the pour cup as the filter tabs pass through the tab slots. The filter is then rotated, relative to the pour cup, such that the filter tabs and tab slots are no longer aligned thereby eliminating the ability of the filter to be withdrawn from the pour cup. Protrusions or depressions in the top of the filter are preferred to facilitate rotation of the filter within the pour cup.
Though referred to as reversibly engaged it is common practice for the pour cup and filter to be single use items and therefore disengagement after filtration is not necessary and may be difficult due to entrapped frozen metal within the assembly.
The invention will be described with reference to the figures forming an integral, non-limiting, component of the disclosure. Throughout the various figures similar elements will be numbered accordingly.
An embodiment of the invention will be described with reference to FIGS. 1 and 6. In FIGS. 1 and 6 an assembled pour cup and filter is illustrated in cross-sectional schematic view as assembled and engaged for use. In FIGS. 1 and 6, the pour cup, 10, is illustrated with the filter, 14, inserted therein. Further details will be more evident upon further discussions provided below.
An embodiment of the invention will be described with reference to FIGS. 2, 3, 5 and 7. FIGS. 2 and 5 are cross-sectional schematic views of a pour cup, 10. FIG. 3 is a schematic side view of a filter, 14, and FIG. 7 is a perspective schematic view.
With further reference to FIGS. 2, 3, 5 and 7 the pour cup comprises a reservoir, 16, which is an area above the filter engagement region, 18, at the bottom of the filter. The reservoir is preferably tapered inward from top to bottom thereby allowing a volume of molten metal to be stored mitigating the necessity of the pouring rate being correlated to the filtering rate. The reservoir also provides adequate head-pressure to insure molten metal passes through the filter. The filter attachment region, 18, comprises a pour cup taper, 20, which matches a filter taper, 22, wherein the diameter at the bottom of the pour cup taper, 24, and the diameter at the bottom of the filter taper, 26, have the same diameter with a variation between the two diameters being within a tolerance of 2.5% and more preferably 2%. If the variation in diameter between the bottom of the pour cup taper and the bottom of the filter taper is greater than about 2% either the filter tabs, 28, will not clear the tab slots, 30, a sufficient distance to engage with the bottom, 32, of the pour cup, or the filter will be loosely fit within the pour cup which is undesirable. In practice the tolerance of the pour cup diameter is lower than the tolerance of the filter diameter due to manufacturing constraints. It is preferable that the tolerance in the diameter of the pour cup diameter be no more than ±2% and the tolerance in the diameter of the filter be no more than ±2.5% based on a common diameter. For many applications a pour cup internal diameter (ID) at the bottom of the pour cup taper is about 2.5 inches without limit thereto.
The diameter of the pour cup taper and filter taper is not particularly limited, however, for most commercial sizes the tapers are both about 30°±10° relative to the bottom, 34, or the pour cup. A higher taper angle increases the contact surface area between the tapers, however, the strength of the filter is compromised due to the decreasing material available for structural integrity at the top of the filter. A smaller taper decreases the contact area which magnifies the depth within which the filter sits in the pour cup thereby reducing the acceptable tolerance in diameters of the pour cup taper and filter taper as discussed above.
Below the pour cup taper is an optional, but preferred, straight section, 32. The straight section provides structural integrity to the bottom of the pour cup and is preferred over a wedge. The straight section is preferably less than 0.5″ thick with about 0.25″ being optimal for demonstration of the invention. In use, the filter is inserted into the pour cup, with tapers parallel, wherein the filter tabs, 28, are aligned with the tab slots, 30, thereby allowing the tapers to mate. The filter is then rotated, relative to the pour cup, such that the filter tabs are no longer aligned with the tab slots thereby causing the filter tabs to engage with the bottom, 34, of the pour cup. The engagement of the filter tabs with the bottom of the pour cup secures the filter in the pour cup. The filter preferably has a cylindrical bottom, 36, with a diameter slightly less than the diameter of the pour cup at the straight section. A rotation assist feature, 38, is preferably either a protrusion or a depression in the surface of the filter which allows the filter to be grasped by a users hand, or an instrument, to assist in rotating the filter within the pour cup.
The filter tabs preferably have a thickness of about 0.075″ to about 0.2″ with about 0.125″ being optimal for demonstration of the invention. Below about 0.075″ the structural integrity of the filter tabs is insufficient. Above about 0.2″ the excess material is not justified in most applications. It is preferable that the filter have at least two tabs with no more than six tabs. Below two tabs the ability of the two tabs to secure the filter in the pour cup may be compromised. If there are more than six filter tabs it becomes difficult to align the filter tabs with the tab slots. About four filter tabs, and corresponding tab slots, is optimal.
An embodiment of the invention will be discussed relative to FIG. 4 wherein a bottom cut-away view is illustrated schematically. In FIG. 4, the pour cup, 10, and filter, 14, are illustrated as engaged. The filter is rotated such that the filter tabs, 28, are not aligned with the tab slots, 30.
The material of construction for the filter and pour cup is not particularly limited. The material is typically limited by the material being filtered with suitable options known in the art suitable for demonstration of the invention. Those materials suitable for use with foam filters, formed by replication of a reticulated organic foam, are particularly suitable. Particularly suitable materials include filters formed from aluminosilicates such as mullite and kyanite; alumina-based materials; fused silica; zirconium based materials; boron oxides and carbides; metal carbides, borides, nitrides and silicides. Silicon carbide is mentioned as exemplary without limit thereto. Fired clay, mullite, alumina, zirconia-toughened alumina, zirconia-toughened mullite, silicon carbide, silica-bonded mullite, and silica-bonded silicon carbide are particularly suitable for demonstration of the invention for use with iron and particularly ductile iron.
A matrix filter is a preferred embodiment. The matrix filter is preferably formed from extruded filaments wherein the extruded filaments comprises a ceramic precursor printed into a matrix filter precursor followed by sintering. The extruded material has liquid properties suitable for allowing extrusion through an orifice, yet the extruded material has solid properties after extrusion sufficient for the extruded filament to be self-sustaining, without sag, over the span between support lattice. The ceramic precursor is selected for compatibility with the material to be filtered. The precursor used to form the matrix filter can include rheology modifiers such as solvents, acids, bases, polymers, and the like where the modifiers are chosen to provide the viscoelasticity sufficient for extrusion and self-sustaining shape. Pore formers may be included to decrease the ceramic density.
The filter and/or pour cup can also be formed by 3-D printing techniques, either additive techniques or milling techniques. The pour cup can be pre-made by any technique common to the art such as casting, shell molding, pressing or molding. In an embodiment the pour cup can be made by the metal caster by shelling the pour cup as part of the wax mold.
The invention has been described with reference to the preferred embodiments without limit thereto. Additional embodiments and improvements may be realized which are not specifically set forth herein but which are within the scope of the invention as more specifically set forth in the claims appended hereto.

Claims

Claimed is:

1. A filtration system comprising:

a pour cup comprising a reservoir and a filter engagement region wherein said filter engagement region comprises a pour cup taper, tab slots and a bottom; and

a filter wherein said filter comprises a filter taper and filter tabs wherein said filter tabs can be received by said tab slots in one rotational orientation of said filter relative to said pour cup and said tab slots engage with said bottom in a second rotational orientation of said filter relative to said pour cup.

2. The filtration system of claim 1 wherein at least one of said pour cup taper or said filter taper have an angle of 30°+10°.

3. The filtration system of claim 1 wherein said reservoir is tapered inward from top to bottom.

4. The filtration system of claim 1 wherein said filter comprises at least two tabs to no more than six tabs.

5. The filtration system of claim 1 wherein said filter further comprises a rotation assist feature.

6. The filtration system of claim 5 wherein said rotation assist feature is selected from a protrusion and a depression.

7. The filtration system of claim 1 wherein said filter is a matrix filter.

8. A method for assembly a filter assembly comprising:

positioning a pour cup comprising a reservoir and a filter engagement region wherein said filter engagement region comprises a pour cup taper, tab slots and a bottom; and

orienting a filter relative to said pour cup wherein said filter comprises a filter taper and filter tabs with said filter tabs aligned with said tab slots;

inserting said filter through said reservoir to a position wherein said filter tabs are received by said tab slots; and

rotating said filter relative to said pour cup wherein said tab slots are not aligned with said tab slots and said filter tabs are engaged with said bottom.

9. The method for assembly a filter assembly of claim 8 wherein at least one of said pour cup taper or said filter taper have an angle of 30°+10°.

10. The method for assembly a filter assembly of claim 8 wherein said reservoir is tapered inward from top to bottom.

11. The method for assembly a filter assembly of claim 8 wherein said filter comprises at least two tabs to no more than six tabs.

12. The method for assembly a filter assembly of claim 8 wherein said filter further comprises a rotation assist feature.

13. The method for assembly a filter assembly of claim 12 wherein said rotation assist feature is selected from a protrusion and a depression.

14. The method for assembly a filter assembly of claim 8 wherein said filter is a matrix filter.