US3557955A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and apparatus for filtering
Assignee: Hydromation Engineering Co
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Filing: 1968-01-09
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Granted: 1971-01-26
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Expires: 1988-01-09
Abstract
Abstract The invention provides a method of and apparatus for filtering which provides the filtering of extremely small particles, greater dirt retention in the filter medium, higher flow rates through the filter medium, a smaller volume of filter medium, and improved backflushing or backwashing to obtain a cleaner medium. The medium is composed of finely divided particulate material which in the preferred embodiment is polyvinyl chloride, polyethylene or wood sawdust, these materials being light and having great strength to provide stable, fine particles capable of being backflushed. While the apparatus can assume many different configurations, liquid permeable retainers preferably are provided at both the inlet and outlet sides of the filter medium. Where the filter medium is located between retainers, it is important to reverse the liquid flow at least through the inlet retainer during backflushing to remove any deposits from that retainer. As will be described, it is possible to use only one liquid permeable retainer together with agitation and hydraulic flow during backflushing to provide a simplified filter which is effective in some applications. The invention also features backflushing of a particulate filter medium which is very compact and contains relatively great dirt loads. Such backflushing utilizes both mechanical and hydraulic forces, and may be accomplished in several different ways. The media can be compacted, if desired, to reduce the size of the voids therein, thereby increasing the effectiveness of the filter medium in entrapping and holding extremely small particles of dirt therein. The filter medium is compacted prior to the filtration operation, such compaction being accomplished in any one of several ways, e.g. by the use of fluid pressure or a differential flow rate.
Inventors
- 👤 Gene Hirs
- 👤 Richard H Wykoff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:53
CPC Classifications
B; B01; B01D; B01D24/00; B01D24/48; B01D24/4884; B01D24/02; B01D24/04; B01D24/08; B01D24/10; B01D24/12; B01D24/46; B01D24/4631; B01D24/4636; B01D24/4668; B01D24/4673; B01D24/4689
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
65 words
The method of filtering as claimed in claim 1 in which said filter medium is compactible to reduce the size of the voids therein, and wherein said method further includes the step of compacting said filter medium prior to said filtering step to reduce the size of the voids in said filter medium and thereby improve filtration of extremely small particles during said filtering step.
Claim 2
Dependent Claim
50 words
The method of filtering as claimed in claim 1 in which said backwashing step is carried out by introducing backwash liquid into said filter medium at a plurality of places within said filter medium separate from the places where contaminated liquid is introduced into and withdrawn from said filter medium.
Claim 3
Dependent Claim
40 words
The method of filtering as claimed in claim 1 in which said backwashing step is carried out by supplying backwash liquid to said filter medium while agitating said filter medium mechanically, and withdrawing said backwash liquid from said filter medium.
Claim 4
Dependent Claim
79 words
The method of filtering as claimed in claim 1 in which said backwashing step is carried out by forming said filter medium into a slurry, transferring said slurry to a separate receptacle, agitating said slurry to thoroughly separate contaminated liquid from said medium, removing said contaminated liquid, adding liquid to reform said filter medium into a slurry, transferring the reformed slurry from said receptacle to the location of said bed, and removing the slurry liquid to reform said bed.
Claim 5
Dependent Claim
79 words
The method of filtering as claimed in claim 5 in which liquid is added to said filter medium in said receptacle after said contaminated liquid has been withdrawn therefrom, the liquid and filter medium is transferred by pumping from said receptacle to put said filter medium in the form of a bed, and said pumping is done under pressure and flow conditions sufficient to compact said filter medium to thereby accomplish the compaction step of the next filtering cycle.
Claim 6
Dependent Claim
143 words
A filter apparaTus including a casing having an inlet for contaminated liquid an d an outlet for filtrate, a filter medium of finely divided particulate material having voids therein, said medium forming a bed within said casing to be traversed by liquid flowing from said inlet to said outlet, said bed being formed of substantially uniform sized particles ranging from about 0.25 millimeters to 0.71 millimeters of organic polymeric material having a uniform density of less than about 1.55, means for introducing backwash liquid into said casing to put the entire filter bed into a slurry, conduit means for conducting said slurry to a remote separating chamber, means in said separating chamber for withdrawing backwash liquid and any admixed dirt from said medium, and additional conduit means for conducting said medium as a slurry back to the bed location with in said casing.
Claim 7
Dependent Claim
87 words
The filter apparatus as claimed in claim 7 in which said backwash means includes a receptacle separate from said casing, means for transferring the slurry of backwash liquid filter medium from said casing to said receptacle, means for draining contaminated liquid from said slurry in said receptacle, an agitator for agitating said slurry in said receptacle during said draining, means to add liquid to said medium in said receptacle to reform a liquid-medium slurry and means for transferring said slurry from said receptacle back to said casing.
Claim 8
Dependent Claim
201 words
A filter apparatus comprising a casing having inlet means for contaminated liquid and an outlet for filtrate, a filter medium consisting essentially of synthetic organic polymeric material having a density of less than about 1.55 and being compressible to reduce the size of the voids therein, said medium forming a bed within said casing to be traversed by liquid flowing from said inlet to said outlet, and backwash means for introducing backwash liquid into said casing and including means for agitating the filter medium thoroughly during backwashing, (1) to put the entire filter bed into a slurry, (2) to mix and scrub the particles with one another to remove contaminants therefrom, and (3) to hydraulically flush the removed contaminants from said particles, and said inlet means including a first means for passing liquid through said filter medium bed at a first flow rate sufficiently high to compress said filter medium bed and thereby reduce the size of the voids therein, and second means for passing contaminated liquid through said compressed filter medium bed at a second flow rate lower than first said flow rate to entrap contaminants from said contaminated liquid in the reduced voids of said compressed filter medium bed.
Claim 9
Dependent Claim
90 words
The filter apparatus as claimed in claim 9 wherein said casing is provided with a pair of separate and distinct inlet openings, one of said openings supplying said liquid to a predetermined area of said filter medium, and second of said openings supplying said contaminated liquid to a different area of said filter medium larger than said predetermined area, and means for selectively supplying liquid to each of said openings so that the flow rate through said medium during compression thereof is greater than the flow rate therethrough during filtration.
Claim 10
Independent Claim
131 words
A method of filtering comprising retaining filter medium of finely divided particulate material having a specific gravity of less than about 1.55 and formed into a bed having voids therein, filtering by passing liquid contaminated with particulate dirt having a particle size of up to about 50 microns under pressure and at a flow rate of at least 6 gallons per square foot per minute through said filter medium to trap contaminants from said liquid in the voids of said filter medium while withdrawing cleaned liquid from said filter medium, terminating the flow of contaminated liquid through said medium only after the voids of said medium become at least partially clogged with at least 5 cubic inches of contaminants per cubic foot oF filter medium, and subsequently backwashing said filter medium.
Claim 11
Dependent Claim
122 words
In a method of filtering dirt from a liquid, rejuvenating a filter medium in the form of a bed of finely divided particulate material mixed with dirt removed from previously filtered liquid, the particulate material having a specific gravity of less than about 1.55, by the steps of transferring the particulate material in admixture with liquid from the location of said bed to an external location, admixing the particulate material with relatively clean liquid while draining off liquid and accumulated dirt from said particulate material, retaining sufficient liquid in admixture with said particulate material to render said material flowable, flowing said material and said sufficient liquid to the location of said bed, and finally removing said sufficient liquid to reform said bed.
Claim 12
Dependent Claim
131 words
A filter apparatus including a cartridge comprising two stationary perforate members one enclosing the other spaced apart from each other for confining a filter medium between the same, a filter medium of fine particulate material contained and confined by said perforate members in said space therebetween, and at least one perforate tube embedded in said filter medium providing a means for distributing backwash liquid for flow into and through said filter medium, said apparatus further including means for supplying liquid to be filtered to one side of said filter medium, means for withdrawing filtered liquid from the other side of said filter medium, means for supplying backwash liquid to said perforate tube for flow from said tube into said filter medium and means for withdrawing backwash liquid from said filter medium.
Claim 13
Dependent Claim
26 words
The filter apparatus of claim 13 in which the particles of said filter medium have an average size in the range from 35-70 U.S. sieve number.
Claim 14
Dependent Claim
17 words
The filter apparatus of claim 13 in which said perforate tube extends parallel to said perforate members.
Claim 15
Dependent Claim
136 words
A filter apparatus including a cartridge comprising inner and outer stationary perforate tubular members disposed concentrically to define an annular space between the same, an annular body defining a filter medium and composed of fine particulate material contained and confined by said tubular members in said annular space therebetween, and at least one perforate tube embedded in said filter medium providing a means for distributing backwash liquid for flow into and through said filter medium, said apparatus further including means for supplying liquid to be filtered to the exterior surface of said outer tubular member, means for withdrawing filtered liquid from the interior of said inner tubular member, means for supplying backwash liquid to said perforate tube for flow from said tube into said filter medium and means for withdrawing backwash liquid from said filter medium.
Claim 16
Dependent Claim
29 words
The filter apparatus of claim 16 wherein said perforate tube for distributing backwash liquid extends substantially parallel to a common axis of said inner and outer perforate tubular members.
Claim 17
Dependent Claim
13 words
The filter apparatus of claim 17 including means for moving said perforate tube.
Claim 18
Dependent Claim
88 words
The filter apparatus of claim 16 including control means comprising solenoid-operated valve means providing an open supply passage to the exterior of said filter medium and an open withdrawal passage from the interior of said inner tubular member during the filtering portion of a cycle of filter operation, said control means including further solenoid operated valve means providing closed passages for said backwash supply and backwash withdrawal means during said filtering portion of said cycle and opening the latter passages automatically during a backwash portion of said cycle.
Claim 19
Dependent Claim
163 words
A filter apparatus including a cartridge comprising inner and outer perforate tubular members disposed concentrically to define an annular space between the same, an annular filter medium of fine particulate material contained and confined by said tubular members in said annular space therebetween, the particles of said filter medium ranging in size from 0.2 millimeters to 0.5 millimeters, and a plurality of perforate tubes embedded in said filter medium and each extending parallel to the common axis of said tubular members, said tubes providing a means for distributing backwash liquid through said filter medium, means supporting said tubes for rotation, said filter apparatus further including drive means coupled to said tubes for rotating the same, means for supplying liquid to be filtered to the exterior surface of said outer tubular member, means for withdrawing filtered liquid from the interior of said inner tubular member, means for supplying backwash liquid to said perforate tubes, and means for withdrawing backwash liquid from said filter medium.
Claim 20
Independent Claim
188 words
A method of filtering comprising confining a finely divided annular particulate filter medium between two concentric perforate retainer members on opposite sides of the filter medium, passing contaminated liquid from one of said retainer members to the other for flow radially through said filter medium under pressure to remove contaminants from said liquid, the pressure passage of said liquid and the removed contaminants incidentally compacting said filter medium and ultimately clogging the same, distributing a backwash liquid throughout said filter medium by introducing the backwash liquid into said annular filter medium through at least one perforate tube embedded in said filter medium, said tube being interposed between said retainer members and extending parallel to the axis of said annular medium, and withdrawing backwash liquid through at least one of said concentric retainer members, so that said backwash liquid passes essentially radially throughout said annular filter medium and exits at the periphery of said annular medium to break up the compactness of said medium and to remove contaminants accreted on said filter medium while the medium is still confined between said members thereby renewing said medium for further filtration.
Claim 21
Dependent Claim
28 words
The method of claim 21 further including the step of traversing said filter medium with liquid and gas in the distribution of backwash liquid throughout said filter medium.
Claim 22
Dependent Claim
159 words
A filter apparatus including a cartridge comprising inner and outer perforate tubular members disposed concentrically to define an annular space between the same, an annular body defining a filter medium and composed of fine particulate material contained and confined by said tubular members in said annular space therebetween, and at least one perforate tube embedded in said filter medium and extending substantially parallel to a common axis of said inner and outer perforate tubular members, said perforate tube providing a means for distributing backwash liquid for flow into and through said filter medium, said apparatus further including means for rotating said perforate tube, means for supplying liquid to be filtered to the exterior of said outer tubular member, means for withdrawing filtered liquid from the interior of said inner tubular member, means for supplying backwash liquid to said perforate tube for flow from said tube into said filter medium, and means for withdrawing backwash liquid from said filter medium.
Claim 23
Dependent Claim
164 words
A filter apparatus including a cartridge comprising inner and outer perforate tubular members disposed concentrically to define an annular space between the same, an annular body defining a filter medium and composed of fine particulate material contained an confined by said tubular members in said annular space therebetween, and a plurality of perforate tubes embedded in said filter medium and extending parallel to a common axis of said tubular members, said tubes providing a means for distributing backwash liquid for flow into and through said filter medium, said apparatus further including means supporting said tubes for rotary movement, a common drive means for rotating said tubes simultaneously, means for supplying liquid to be filtereD to the exterior surface of said outer tubular member, means for withdrawing filtered liquid from the interior of said inner tubular member, means for supplying backwash liquid to said perforate tubes for flow from said tubes into said filter medium and means for withdrawing backwash liquid from said filter medium.
Claim 24
Independent Claim
158 words
A method of filtering comprising providing a filter bed consisting essentially of finely divided particles of a uniform material selected from the group consisting of polyethylene and polyvinyl chloride, said particles being generally spherical with pock-marked surfaces and having an average particle size in the range from about 0.25 to about 0.42 millimeters, and said bed having a porosity of about 60 percent to about 80 percent, passing contaminated liquid through said filter bed under pressure to remove contaminants from said liquid and to accrete the contaminants in said filter bed, the pressure passage of said liquid incidentally compacting said filter bed and ultimately clogging the same, mixing and agitating a backwash liquid with said filter bed to break up the compactness of said bed and to remove contaminants accreted in said bed, separating from said particles at least a portion of said backwash liquid with the contaminants suspended therein, and reforming said particles into said filter bed.
Claim 25
Dependent Claim
27 words
The method of claim 25 in which said particles consist essentially of polyvinyl chloride having a bulk density on the order of 25 pounds per cubic foot.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-25 | 1974-07-27 | 1975-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-25 | 1978-07-27 | 1979-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-25 | 1982-07-27 | 1983-01-26 | $7700.00 | Window Closed / Lapsed |