U.S. patent number RE34,636 [Application Number 07/813,970] was granted by the patent office on 1994-06-14 for apparatus for filtering liquids.
Invention is credited to Thomas H. Bivens.
United States Patent |
RE34,636 |
Bivens |
June 14, 1994 |
Apparatus for filtering liquids
Abstract
Apparatus for filtering contaminants from liquids such as
cooking oil is disclosed. A filter assembly comprises an envelope
formed of an upper wire mesh filter element and a lower wire mesh
filter element joined about their peripheral edges and a porous
insert filter member removably contained centrally within the
envelope which has a plurality of voids allowing vertical and
lateral fluid flow therethrough. The filter assembly is releasably
secured in the assembled condition by a fastener which is adapted
to be connected to a pump and the fastener has fluid passageways in
communication with .Iadd.the lateral flow passages in .Iaddend.the
porous insert for drawing fluid through the upper and lower filter
elements and said insert. The upper and lower filter elements of
the envelope are formed of stainless steel mesh and the porous
insert filter member is formed of apertured aluminum plate. The
filter assembly is suited for use in combination with food cooking
apparatus employing cooking oil disposed in a container in which
food particles and other particulate matter become deposited and
may be used in place of conventional cooking oil filter apparatus.
The apparatus is also suitable for use in systems employing a
filter powder disbursed in the cooking oil to be filtered.
Inventors: |
Bivens; Thomas H. (Magnolia,
TX) |
Family
ID: |
22004155 |
Appl.
No.: |
07/813,970 |
Filed: |
December 24, 1991 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
056402 |
May 29, 1987 |
04805525 |
Feb 21, 1989 |
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Current U.S.
Class: |
99/408;
210/167.28; 210/232; 210/461; 210/DIG.8 |
Current CPC
Class: |
A47J
37/1223 (20130101); B01D 29/41 (20130101); Y10S
210/08 (20130101) |
Current International
Class: |
A47J
37/12 (20060101); B01D 29/39 (20060101); B01D
29/41 (20060101); A47J 037/12 () |
Field of
Search: |
;99/408,409,403,407
;210/DIG.8,167,232,461,486 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"New! Permafil Oil Filters"; Filtration International, Inc.
Houston, Texas; date unknown. .
"Permafil" Brochure; Edible Oil Division, Houston Texas; date
unknown. .
The Filter Magic.RTM. System by Frymaster Wellbilt Company Bulletin
No. 818-001 Rev. Nov. 1986 date unknown. .
ReNu Brochure, ReNu Vacuum Filter Manufacturing Company, date
unknown. .
R. F. Hunter Co., Inc. Brocuure, date unknown. .
Robot Coupe U.S.A. Inc. Brochure, date unknown. .
Castle, Filter Brochure, The Prince Castle Company, date unknown.
.
Fastfilter.RTM. Assembly and Operating Instructions, date
unknown..
|
Primary Examiner: Simone; Timothy F.
Attorney, Agent or Firm: Keeling & Associates
Claims
I claim:
1. In combination with food cooking apparatus employing cooking oil
disposed in a container in which food particles and other
particulate matter become deposited, a cooking oil filtering
apparatus comprising:
a filter assembly disposed in the cooking oil in the container
comprising a deformable porous filter insert member of a relatively
rigid material containing sufficient voids .Iadd.and passages
.Iaddend.to allow vertical and lateral fluid flow therethrough,
said filter insert being removably contained within and surrounded
by an upper and a lower stainless steel wire mesh filter
element,
a peripherally extending fastener releasably securing said filter
insert and the wire mesh filter element in an assembled
condition,
a hollow fitting secured centrally of one of said wire mesh filter
elements having fluid passageways in communication .Iadd.with
lateral passages in .Iaddend.said filter insert,
suction means operatively connected to said hollow fitting for
drawing cooking oil from said container through said wire mesh
filter elements and thence through said filter insert to filter the
cooking oil,
fluid transmission means operatively connected to said suction
means for transmitting the filtered cooking oil to a desired
destination, and
coagulating means disbursed in the cooking oil for providing filter
cake directly on the outer surface of said wire mesh filter
elements.
2. The combination according to claim 1 in which
said releasable fastener comprises a substantially rectangular
frame securing said filter insert and said wire mesh filter members
therebetween,
one portion of said frame being releasably secured and operable on
release to pivot to an open position permitting removal of said
plate.
3. The combination according to claim 2 wherein
said upper and lower wire mesh filter elements are formed of
24.times.110 stainless steel wire mesh with 0.0145 inch and 0.0090
strand diameters respectively.
4. The combination according to claim 2 wherein
said upper and lower wire mesh filter elements are formed of
80.times.70 stainless steel wire mesh with strand diameter of
0.0055 inches.
5. The combination according to claim 2 wherein
said upper and lower wire mesh filter elements are formed of 100
stainless steel wire mesh with strand diameter of 0.0045
inches.
6. The combination according to claim 2 wherein said interior
filter member is comprised of aluminum plate.
7. The combination according to claim 2 wherein
said coagulating means is comprised of diatomaceous earth.
8. In combination with food cooking apparatus employing cooking oil
disposed in a container in which food particles and other
particulate matter become deposited, a cooking oil filtering
apparatus comprising:
a filter assembly disposed in the cooking oil in the container
comprising a substantially rectangular channel-shaped frame,
one portion of said frame being releasable secured and operable on
release to pivot to an open position,
a pair of wire mesh filter members secured at their peripheries in
said channel-shaped frame,
a deformable porous interior filter insert member of a relatively
rigid material removably positioned between said wire mesh filter
members and containing sufficient voids .Iadd.and passages
.Iaddend.to allow vertical and lateral fluid flow therethrough,
hollow washer members secured centrally of each of said wire mesh
filter members,
a hollow washer member secured centrally of said filter insert,
said washer members being aligned .[.when.]. .Iadd.with
.Iaddend.said filter insert washer members .[.with its washer
member.]. abutting .[.the washer member of one of.]. said
.[.were.]. .Iadd.wire .Iaddend.mesh filter members,
said hollow fitting having an opening positioned inside said filter
insert .Iadd.and communicating with said lateral passages therein
.Iaddend.and having an opening at its end outside said filter
assembly,
suction means operatively connected to the outside opening of said
fitting for drawing cooking oil from said container through said
wire mesh filter elements and thence through said filter insert to
filter the cooking oil,
fluid transmission means operatively connected to said suction
means for transmitting the filtered cooking oil to a desired
destination, and
coagulating means disbursed in the cooking oil for providing filter
cake directly on the outer surface of said wire mesh filter
elements. .Iadd.
9. The combination according to claim 1 in which
said filter insert comprises a flat rectangular metal plate slitted
and the material deformed to form interrupted tubular openings in
edge view, said tubular openings providing said lateral
passages,
said peripherally extending releasable fastener comprises a
substantially rectangular frame securing said filter insert plate
and said wire mesh filter members therebetween, and
one portion of said frame being releasably secured and operable on
release to pivot to an open position permitting removal of said
plate. .Iaddend.
Description
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates generally to filtering apparatus, and
more particularly to a filter assembly for the effective filtration
of liquids such as cooking oil without the requirement of filter
paper or other disposable filter elements.
BRIEF DESCRIPTION OF THE PRIOR ART
Cooking oil is extensively used in the food industry to cook
various comestibles. Animal fat or other suitable material may
sometimes be used as the cooking material in lieu of cooking oil.
The term "cooking oil" is used herein to designate any such
material. Frying is frequently accomplished in relatively deep
containers with the comestible to be cooked immersed in the cooking
oil. In cases where quantities of food are regularly cooked in such
a manner, the cooking oil becomes contaminated with various
particles of food or other impurities, and charred food particles
produce an odor which adversely affects the taste of foods cooked
therein. Clean cooking oil further provides relatively efficient
utilization of energy in the cooking process.
Wire mesh strainers have been long known and used to remove
particulate matter from cooking oil. Strainers have not been
effective, however, to remove sufficient particulate matter to
provide particulate-free cooking oil, and have been demonstrated to
only slightly prolong the usefulness of the cooking oil.
To beneficially control free fatty acids in the cooking oil,
suspended particles of the size of two (2) microns and larger
should be removed from the cooking oil.
As presently commercially practiced, cooking oil is cleaned by
pumping it through a filter assembly containing filter paper or
other disposable filter element. A filter powder is normally
applied to the filter element by dispersal in the cooking oil being
cleaned to precipitate particulates and to control odor. Filter
powders commonly consist of diatomaceous earth or pearlite;
however, some consist of chemical mixtures.
A principal disadvantage of the presently practiced methods of
filtering is the requirement of paper or other disposable filter
element. In restaurants with high volumes of food processing, paper
filters are commonly changed four to six times per day. Disposable
filter elements require the time and expense of disassembly of the
filter assembly from time to time to replace the filter element,
and require the expense of the disposable filters.
Additionally, disposable filters tend to be easily damaged. Tears
or other voids in filters may result in particulate matter and
filter powder flowing through the pump with consequent reduced pump
life and efficiency, filter powder accumulation on heating
elements, and filter powder contamination of the cooking oil.
Kyle, U.S. Pat. No. 4,604,203 discloses a cooking oil filtering
apparatus and filter therefor involving a layered filter formed of
a porous web of microfibers and supported by a material more porous
than the microfiber web. The filter material disclosed is not
purported to be a permanent material thus replacement is required
from time to time.
Bisko, U.S. Pat. No. 3,735,871 discloses a cloth filter jacket for
a cooking oil filtering apparatus, the purported purpose of which
is to provide a jacket which enables cleaning of the filter
assembly by scraping, thus prolonging the time periods between
disassembly of the filter apparatus and replacement of the
disposable filter element.
Shepherd, U.S. Pat. No. 3,279,605 discloses a filter assembly
providing for pumping of the cooking oil through the filter
assembly, which filter assembly includes a disposable filter
medium.
Gedrich, U.S. Pat. No. 3,263,818 discloses a cooking oil filtering
apparatus providing pumping of the filtered cooking oil to its
original, or other, container. The filter assembly disclosed
includes a disposable filter element.
Miles, et al, U.S. Pat. No. 2,760,641 discloses a portable
filtering apparatus providing pumping of the cooking oil through
the filter assembly, which filter assembly includes a disposable
filter element.
Overbeck, U.S. Pat. No. 2,635,527 discloses a deep frying strainer
to be located at the bottom of the cooking oil container to strain
food particles from cooking oil as the strainer is lifted from the
container and the liquid is forced through the strainer by the
action of gravity. Although beneficial to remove much particulate
matter, the invention disclosed does not effectively remove smaller
particulate contaminants.
.Iadd.A sales brochure (undated, but known to have been published
in 1985) by Filtration International, Inc., entitled "New! Permafil
Oil Filters Eliminates Filter Papers" (Model FIP-110), discloses a
stainless steel filter similar in some respects but dissimilar in
others to the present invention. Photographs of this filter and a
more complete description are set forth in an accompanying prior
art statement. .Iaddend.
The inventions disclosed and the current known practice of
filtering cooking oil indicate that paper filters or other
disposable filters are required to remove sufficient small
particulate matter to provide for continued re-use of cooking oil
required in commercial cooking applications. Disadvantages of
disposable filters include the cost of the filters and the time and
expense involved in the disassembly of the filter assembly and
replacement of the filters.
The present invention is distinguished over the prior art in
general, and these patents .Iadd.and the Filtration International
Brochure, .Iaddend.in particular .Iadd.by .Iaddend.a filter
apparatus comprising an envelope formed of an upper wire mesh
filter element and a lower wire mesh filter element joined about
their peripheral edges and a porous insert filter member removably
contained centrally within the envelope which has a plurality of
voids allowing vertical and lateral fluid flow therethrough. The
filter assembly is releasably secured in the assembled condition by
a fastener which is adapted to be connected to a pump and the
fastener has fluid passageways in communication with .Iadd.the
laterally extending passages in .Iaddend.the porous insert for
drawing fluid through the upper and lower filter elements and said
insert. The upper and lower filter elements of the envelope are
formed of stainless steel mesh and the porous insert filter member
is formed of apertured aluminum plate.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a
filtering apparatus that effectively removes particulate matter
from cooking oil without the necessity of regular replacement of
the filter element.
It is another object of the present invention to provide a filter
assembly incorporating a permanent filter element to provide for
relatively efficient and economical filtering of cooking oil.
It is another object of the present invention to provide a filter
assembly incorporating a permanent filter element that can be
readily adapted to replace existing filter assemblies in a variety
of applications.
It is another object of this invention to provide a filter assembly
resistant to damage.
It is a further object of this invention to provide a filter
element that can be readily repaired.
It is a further object of the present invention to provide a method
of filtering particulate matter from cooking oil without the use of
disposable filters.
Other objects of the invention will become apparent from time to
time throughout the specification and claims as hereinafter
related.
The above noted objects and other objects of the invention are
accomplished by the present apparatus for filtering contaminants
from liquids which includes a filter assembly comprising an
envelope formed of an upper wire mesh filter element and a lower
wire mesh filter element joined about their peripheral edges and a
porous insert filter member removably contained centrally within
the envelope which has a plurality of voids allowing vertical and
lateral fluid flow therethrough. The filter assembly is releasably
secured in the assembled condition by a fastener which is adapted
to be connected to a pump and the fastener has fluid passageways in
communication with .Iadd.the lateral flow passages in .Iaddend.the
porous insert for drawing fluid through the upper and lower filter
elements and said insert. The upper and lower filter elements of
the envelope are formed of stainless steel mesh and the porous
insert filter member is formed of apertured .Iadd.slitted
.Iaddend.aluminum plate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross sectional view of the filtering apparatus in
accordance with the present invention being employed to filter
cooking oil.
FIG. 2 is a cross sectional view schematically illustrating the
filter assembly of the present invention.
FIG. 3 is a top plan view of the filter assembly of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings by numerals of reference, there is shown
schematically in FIG. 1, apparatus for filtering cooking oil. The
apparatus comprises a filter assembly 10 installed in a container
11 containing a quantity of cooking oil 12, a delivery tube 14
connecting the filter assembly 10 to a pump 13, and a pump outlet
tube 15 providing for transmission of fluid from the pump 13 to the
container 11 or other desired destination. The pump is
schematically shown as it may be of any appropriate conventional
design.
As shown in FIGS. 2 and 3, the filter assembly 10 comprises a
generally flat filter insert member 16 of square or rectangular
configuration enclosed centrally within a wire mesh envelope 17.
The envelope 17 is formed of an upper wire mesh filter element 18
and a lower wire mesh filter element 19 of equal size. The filter
elements 18 and 19 are of sufficient length and width to extend
beyond the edges of the insert member 16.
Filter insert 16 is formed of relatively rigid metallic material,
such as aluminum, and contains sufficient voids to allow the free
flow of fluids therethrough .Iadd.both vertically and
laterally.Iaddend.. The insert surface area is sufficient to
support the relatively flexible mesh of the upper filter element 18
and the lower filter element 19. The filter insert 16 is
preferrably constructed of deformable material (such as aluminum)
so that it may be deformed to conform with the contour of cooking
oil containers having rounded bottoms. Such deformity allows
cooking oil to be circulated from the lower recesses of such
containers. Aluminum plate having a tubular slit grid has been
proven to be a material which is suitably plastic and suitably
rigid at temperatures incurred in cooking oil applications and also
provides .Iadd.passages for .Iaddend.a vertical and lateral fluid
path.
Upper filter element 18 and lower filter element 19 may be formed
of flexibly rigid and durable wire mesh, such as stainless steel. A
strand mesh configuration is preferred because it is more suitable
for use with comestibles. Wire mesh of the following warp and fill
(expressed in strands per inch) and with the indicated respective
diameters have been determined to be suitable:
24.times.110 stainless steel wire mesh with 0.0145 inch and 0.90
inch strand diameters respectively;
80.times.70 stainless steel wire mesh with strand diameter of
0.0055 inches; and
100 stainless steel wire mesh with strand diameter of 0.0045
inches.
It should be understood that other combinations of warp and fill
and strand sizing or material of construction may be practiced
without departing from the scope of the invention.
U-shaped channel members 22, 23 and 24 are located along three
outer edges of upper filter element 18 and lower filter element 19.
Channel members 22, 23 and 24 maintain the three edges of filter
elements 18 and 19 in a contiguous configuration within the channel
of the U-shaped channel members 22, 23 and 24 along the length of
each respective edge. The three edges contiguously joined by
channel members 22, 23 and 24 along the length of each respective
edge. The three edges contiguously joined by channel members 22, 23
and 24 in conjunction with the remaining unengaged edges of upper
filter element 18 and lower filter element 19 form a pocket into
which filter insert 16 is inserted. Channel members 22, 23 and 24
may be permanently attached to upper filter element 18 and lower
filter element 19 and may be permanently attached at their points
of intersection. Suitable means for attachment include spot
welding.
Another U-shaped channel member 25 is pivotally connected to the
end of channel member 22 at hinge 42. After insertion of filter
insert 16 into the envelope pocket, the nonattached end of channel
member 25 is rotated toward the unconnected edge of filter elements
18 and 19 until the nonattached end connects the end of channel
member 24, and is releasably attached thereto by spring 30, with
the edges of upper filter element 18 and lower filter element 19
maintained within the channel of U-shaped channel member 25. Upon
connection of channel member 25 to channel member 24, upper filter
element 18 and lower filter element 19 are connected at their outer
edges around their entire periphery surrounding filter insert 16.
The peripheral edges of upper filter element 18 and lower filter
element 19 may be plazma-welded prior to connection of channel
members 22, 23, 24, and 25 to prevent tearing or unraveling of the
exposed ends.
Apertures 26, 27, and 28 are provided through the center of upper
filter element 18, lower filter element 19 and filter insert 16
respectively. Flat collar members 31 and 32 are attached at the
upper and lower surfaces of upper filter element 18 to surround the
aperture 26. Flat collars 33 and 34 are attached at the upper and
lower surfaces of lower filter element 19 to surround the aperture
28. The internal diameter of the collars 31-34 and the apertures
26-28 is sufficient to slidably receive the threaded shaft 35 of a
fastener or closure plug 36 having an enlarged diameter head or
flange 37.
The threaded shaft 35 of closure plug 36 is inserted upwardly
through the collars 31-34 until the flange 37 bears against the
lowermost collar 34 and the threaded shaft extend beyond the
uppermost collar 31. A cylindrical cap 38 having a threaded
longitudinal bore 39 is threadedly received on the threaded shaft
35. The cap 38 is threadedly tightened against the upper collar 31
to compressibly secure the insert 16, upper filter element 18 and
lower filter element 19 together. The collars 31-34 are constructed
of relatively rigid material and protect upper filter element 18
and lower filter element 19 from damage due to compressive and
angular forces resulting from closure of the cap 38.
Thus, the insert 16, upper filter element 18 and lower filter
element 19 are effectively clamped between the flange 37 and the
bottom of the cap 38. The length of the cap 38 is such that
sufficient threads remain at the top of the cap to threadedly
receive and removably connect the filter assembly to a delivery
tube 14.
A central longitudinal port 40 extends inwardly within the closure
plug 36 a distance from the end of the threaded shaft 35 and a
plurality of circumferentially spaced transverse ports 41 extend
through the shaft in communication with the central port 40. The
ports 41 are axially aligned on the closure plug shaft 35 to reside
generally between the upper and lower surface of the insert 16.
Filter insert 16 is preferrably provided with a multiplicity of
voids, which allow free flow of fluids through the insert 16 in
vertical and/or lateral direction and .Iadd.laterally through
passages in the insert .Iaddend.through the ports 41 and central
port 40. Fluid communication is thus provided between the interior
of delivery tube 14 and the exterior of the filter assembly.
The delivery tube 14 and the pump outlet tube 15 may be constructed
with one or more flexible sections, and the pump 13 may be so sized
such that the filtering apparatus of the present invention may be
transported from place to place.
OPERATION
When using the filtering apparatus of the present invention, a
filter powder is employed. The filter powder may be comprised of
diatomaceous earth or pearlite or chemical mixtures or a
combination thereof. As depicted in FIG. 1, the filtering apparatus
is located near the container 11 of cooking oil 12 to be filtered
and the filter assembly 10 located at or near the bottom of the
container 11. Filter powder (not shown) is dispersed in the cooking
oil 12. Upon activation of the pump 13, cooking oil 12 is drawn by
suction applied by the pump 13 through upper filter element 18 and
lower filter element 19, through the relatively more porous filter
insert 16 .Iadd.and the lateral passages therein.Iaddend., through
ports 41 through central port 40 and through delivery tube 14 to
the pump 13. The cooking oil 12 may be transmitted back to the
container 11, or transmitted to such other destination as is
desired, through the pump outlet tube 15.
Particles of filter powder and other particulate matter dispersed
within the cooking oil 12 are drawn by the flow path of the cooking
oil 12 to the outer surfaces of upper filter element 18 and lower
filter element 19. The flow path of the cooking oil 12 in
conjunction with the composition of the particulate matter cause
the particulate matter to aggregate at the outer surfaces of upper
filter element 18 and lower filter element 19. The suction applied
to the cooking oil 12 maintains fluidic channels within such
aggregation allowing for the continued filtering of cooking oil 12
despite such aggregation.
The relatively rigid yet porous configuration of filter insert 16
provides support to upper filter element 18 and lower filter
element 19 while providing fluidic communication with the central
port 40.
The flexible mesh upper filter element 18 and lower filter element
19 in conjunction with the supportive yet porous filter insert 16,
the suction provided by pump 13, and the filter powder thus provide
a filtering assembly which may be practiced without the requirement
of disposable filter elements.
From the foregoing it may be seen that the present filter assembly,
being constructed of durable materials, may be scraped to remove
filter powder and particulate matter accumulated thereon, and may
further be scraped during operation without adversely affecting the
filtering operation. The present filter assembly may further be
cleaned by the application of cleaning fluids without disassembling
the filter apparatus. The present filter assembly eliminates shut
down time during operation of the filter assembly, and results in
substantial savings in cost of filter powder, in the elimination of
paper or other disposable filter elements, and in the cost of
labor. It has been determined that regular application of
commercially available products designed to prevent accumulation of
cooking oil and comestibles on cooking utensils effectively
prevents the buildup of such materials on the mesh of the filter
elements.
The filter elements of the present filter assembly may be easily
repaired if damaged by patching, welding or soldering the affected
area. Such repair may be accomplished without the necessity of
disassembly of the filtering apparatus.
The filter assembly of the present invention may be readily adapted
to conform to a variety of existing commercially available
filtering assemblies presently using disposable filter medium.
Although a square or rectangular filter assembly is shown in the
drawings, the invention may be practiced with any suitable shape or
configuration.
While the filter assembly of the present invention is particularly
suitable for filtering cooking oils used in deep frying, the
filtering apparatus may also be used in filtering other liquids,
particularly liquids containing suspended solids.
While this invention has been described fully and completely with
special emphasis on a preferred embodiment, it should be understood
that within the scope of the appended claims the invention may be
practiced otherwise than as specifically described herein.
* * * * *