# US 5,702,607 A · On-site automated closed loop petroleum based hydrocarbon fluid filtration and recycling system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,702,607 A - Document ID: US5702607A - Status: Granted - Kind: A - Application number: 08/676,983 - Filed: 1996-07-08 - Granted: 1997-12-30 - Earliest claimed: 1996-07-08 - Inventors: David M. Lawson - Web page: https://patentgrep.com/patent/US5702607A ## CPC - B01D 29/27: Filter bags - B01D 29/56: in series connection - Y10S 210/917: Color - 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) - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract An on-site automated closed loop petroleum based hydrocarbon fluid filtration and recycling system that continuously recycles a spent petroleum based hydrocarbon fluid and simultaneously continuously dispenses the recycled petroleum based hydrocarbon fluid. The system includes a hollow and open-top fluid reservoir, a lid that selectively opens and closes the hollow and open-top fluid reservoir, inlet apparatus that inputs the spent petroleum based hydrocarbon fluid into the hollow and open-top fluid reservoir, outlet apparatus that outputs the recycled petroleum based hydrocarbon fluid from the hollow and open-top fluid reservoir, a first filtering stage that removes large particles of dirt and grease from the spent petroleum based hydrocarbon fluid passing therethrough, a second filtering stage that removes small particles of dirt and grease from the spent petroleum based hydrocarbon fluid passing therethrough, a submersible internal pump that draws in the spent petroleum based hydrocarbon fluid passing through the second filtering stage, a third filtering stage that adsorbs grease and dirt from the spent petroleum based hydrocarbon fluid passing therethrough, a fourth filtering stage that removes discoloration from the spent petroleum based hydrocarbon fluid passing therethrough. ## Claims ### Claim 1 An on-site automated closed loop petroleum based hydrocarbon fluid filtration and recycling system having an operating time and continuously recycling a spent petroleum based hydrocarbon fluid having a time of use and simultaneously continuously dispensing a recycled petroleum based hydrocarbon fluid which is the spent petroleum based hydrocarbon fluid after being recycled, comprising: a) a hollow and open-top fluid reservoir having a closed bottom with an inner surface, and an open top disposed above said closed bottom of said hollow and open-top fluid reservoir; b) a lid having an outer surface, an inner surface, an inlet throughport extending vertically therethrough, an output throughport extending vertically therethrough, and selectively opening and closing said open top of said hollow and open-top fluid reservoir, so that internal components housed in said hollow and open-top fluid reservoir can be readily serviced; c) inlet means for inputting the spent petroleum based hydrocarbon fluid into said hollow and open-top fluid reservoir; said inlet means being disposed in said inlet throughport in said lid; d) outlet means for outputting the recycled petroleum based hydrocarbon fluid from said hollow and open-top fluid reservoir; said outlet means being disposed in said outlet throughport in said lid; e) a first filtering stage contained in said hollow and open-top fluid reservoir and being removably attached to said inlet means; said first filtering stage removing large particles of dirt and grease from the spent petroleum based hydrocarbon fluid passing therethrough; f) a second filtering stage encasing said first filtering stage and being contained in said hollow and open-top fluid reservoir; said second filtering station being removably attached to said inlet means and removing small particles of dirt and grease from the spent petroleum based hydrocarbon fluid passing therethrough; g) a submersible internal pump having an operating time and being disposed in said hollow and open-top fluid reservoir on said inner surface of said closed bottom of said hollow and open-top fluid reservoir, in proximity to said outlet means; said submersible internal pump drawing in the spent petroleum based hydrocarbon fluid passing through said second filtering stage; h) a third filtering stage contained in said hollow and open-top fluid reservoir and being tandemly disposed to said first filtering stage and said second filtering stage; said third filtering stage adsorbing grease and dirt from the spent petroleum based hydrocarbon fluid passing therethrough; i) connecting means for fluidly connecting said submersible internal pump to said third filtering stage and being contained in said hollow and open-top fluid reservoir; said connecting means transporting the spent petroleum based hydrocarbon fluid drawn in by said submersible internal pump to said third filtering stage; and j) a fourth filtering stage encasing said third filtering stage and being contained in said hollow and open-top fluid reservoir; said fourth filtering station removing discoloration from the spent petroleum based hydrocarbon fluid passing therethrough, so that the spent petroleum based hydrocarbon fluid passes downwardly through said first filtering stage and is purged of large particles of dirt and grease, then passes downwardly through said second filtering stage and is purged of small particles of dirt and grease, then is drawn into said submersible internal pump, then is pumped upwardly through said connecting means, then passes downwardly through said third filtering stage and is purged of dirt and grease, then passes downwardly through said fourth filtering stage and is purged of discolorations, then enters into said hollow and open-top fluid reservoir, and then is drawn into said outlet means as the recycled petroleum based hydrocarbon fluid. ### Claim 2 (depends on 1) The system as defined in claim 1, wherein said hollow and open-top fluid reservoir is a 55 gallon circular-cylindrically-shaped and open-top drum and said lid is a circular-shaped lid so as to be compatible with said 55 gallon circular-cylindrically-shaped open-top drum. ### Claim 3 (depends on 1) The system as defined in claim 1, wherein said outlet means is a conduit that passes sealingly through said outlet throughport in said lid and terminates at a free end thereof in said hollow and open-top fluid reservoir slightly above said inner surface of said closed bottom of said hollow and open-top fluid reservoir. ### Claim 4 (depends on 1) The system as defined in claim 1, wherein said lid further has a pair of spaced-apart canister mounting throughbores that extend vertically therethrough, and a power line throughbore that extends vertically therethrough. ### Claim 5 (depends on 1) The system as defined in claim 1, wherein said submersible internal pump is selected from the group consisting of electric and hydraulic. ### Claim 6 (depends on 1) The system as defined in claim 1; further comprising an external timer that is disposed externally of said hollow and open-top fluid reservoir; said external timer is in communication with said submersible internal pump through a conduit that extends from said external timer, sealingly through said power line throughbore in said lid, and to said submersible internal pump, so that the operating time of said submersible internal pump and thereby said operating time of said on-site automated closed loop petroleum based hydrocarbon fluid filtration and recycling system can be controlled. ### Claim 7 (depends on 1) The system as defined in claim 1, wherein said operating time of said on-site automated closed loop petroleum based hydrocarbon fluid filtration and recycling system is approximately twice the time of use of the spent petroleum based hydrocarbon fluid to be recycled. ### Claim 8 (depends on 1) The system as defined in claim 1, wherein said inlet means includes an external fitting that has a hollow, cylindrically-shaped, and wide lower portion that sealingly passes vertically downwardly into said inlet throughport in said lid slightly past said inner surface of said lid, and a hollow, cylindrically-shaped, and narrow upper portion that is collinear with, in fluid communication with, and narrower than, said hollow, cylindrically-shaped, and wide lower portion of said external fitting of said inlet means; said hollow, cylindrically-shaped, and narrow upper portion of said inlet means extends vertically upwardly slightly past said outer surface of said lid; said inlet means further includes an internal fitting that has a hollow and cylindrically-shaped portion with a circumferentially-disposed and radially-outwardly-extending flange that extends circumferentially around, and radially outwardly from, a lower end thereof; said hollow and cylindrically-shaped portion of said internal fitting of said inlet means sealingly passes vertically upwardly into said inlet throughport in said lid, with said circumferentially-disposed and radially-outwardly-extending flange of said lower end of said hollow and cylindrically-shaped portion of said internal fitting of said inlet means disposed below said lid; said hollow and cylindrically-shaped portion of said internal fitting of said inlet means snugly engages, and is in fluid communication with, said hollow, cylindrically-shaped, and wide lower portion of said external fitting of said inlet means, with said lid being engaged therebetween. ### Claim 9 (depends on 8) The system as defined in claim 8, wherein said first filtering stage is an empty porous polyester draw bag that is removably secured, by a draw string, around said hollow and cylindrically-shaped portion of said internal fitting of said inlet means and extends vertically downwardly therefrom, with said circumferentially-disposed and radially-outwardly-extending flange of said lower end of said hollow and cylindrically-shaped portion of said internal fitting of said inlet means providing a seal therebetween against leaks, while said draw string of said empty porous polyester draw bag of said first filtering stage allows for quick and easy replacement thereof. ### Claim 10 (depends on 9) The system as defined in claim 9, wherein said empty porous polyester draw bag of said first filtering stage is 4" in diameter, 12" in length, and has a porosity in the range of 100-200 microns when the spent petroleum based hydrocarbon fluid is a cleaning solvent, and has a porosity in the range of 50-100 microns when the spent petroleum based hydrocarbon fluid is a blanket wash. ### Claim 11 (depends on 10) The system as defined in claim 10, wherein said porosity of said empty porous polyester draw bag of said first filtering stage is 200 microns when the spent petroleum based hydrocarbon fluid is a cleaning solvent, and is 50 microns when the spent petroleum based hydrocarbon fluid is a blanket wash. ### Claim 12 (depends on 9) The system as defined in claim 9, wherein said second filtering stage is an empty porous polyester draw bag that encases said empty porous polyester draw bag of said first filtering stage; said empty porous polyester draw bag of said second filtering stage is removably secured, by a draw string, around said hollow and cylindrically-shaped portion of said internal fitting of said inlet means and extends vertically downwardly therefrom, with said circumferentially-disposed and radially-outwardly-extending flange of said lower end of said hollow and cylindrically-shaped portion of said internal fitting of said inlet means providing a seal therebetween against leaks, while said draw string of said empty porous polyester draw bag of said second filtering stage allows for quick and easy replacement thereof. ### Claim 13 (depends on 12) The system as defined in claim 12, wherein said empty porous polyester draw bag of said second filtering stage is 6" in diameter, 18" in length, and has a porosity in the range of 1-100 microns when the spent petroleum based hydrocarbon fluid is a cleaning solvent, and has a porosity in the range of 1-50 microns when the spent petroleum based hydrocarbon fluid is a blanket wash. ### Claim 14 (depends on 13) The system as defined in claim 13, wherein said porosity of said empty porous polyester draw bag of said second filtering stage is 100 microns when the spent petroleum based hydrocarbon fluid is a cleaning solvent, and is 5 microns when the spent petroleum based hydrocarbon fluid is a blanket wash. ### Claim 15 (depends on 1) The system as defined in claim 1; further comprising a hollow canister that contains said third filtering stage and said fourth filtering stage; said hollow canister being disposed in said hollow and open-top fluid reservoir in tandem to said first filtering stage and said second filtering stage and having a circular-cylindrically-shaped top cap with a circular-shaped closed top that has an outer surface an inner surface with a center; said circular-cylindrically-shaped top cap of said hollow canister further having an open bottom, and a hollow and cylindrically-shaped side with a throughbore extending horizontally therethrough. ### Claim 16 (depends on 15) The system as defined in claim 15, wherein said circular-cylindrically-shaped top cap of said hollow canister further has a pair of spaced-apart and threaded canister mounting rods that have vertical axes and extend vertically upwardly from said outer surface of said circular-shaped closed top of said circular-cylindrically-shaped top cap of said hollow canister, from a diameter thereof; said pair of spaced-apart and threaded canister mounting rods of said diameter of said outer surface of said circular-shaped closed top of said circular-cylindrically-shaped top cap of said hollow canister pass through said pair of spaced-apart canister mounting throughbores in said lid and threadably engage canister mounting nuts, with said outer surface of said circular-shaped closed top of said circular-cylindrically-shaped top cap of said hollow canister abutting against said inner surface of said lid. ### Claim 17 (depends on 16) The system as defined in claim 16, wherein said circular-cylindrically-shaped top cap of said hollow canister further has a hollow and cylindrically-shaped portion that extends vertically downwardly from said center of said inner surface of said circular-shaped closed top of said circular-cylindrically-shaped top cap of said hollow canister, in a position equidistantly between said vertical axes of said pair of spaced-apart and threaded canister mounting rods of said diameter of said outer surface of said circular-shaped closed top of said circular-cylindrically-shaped top cap of said hollow canister; said hollow and cylindrically-shaped portion of said center of said inner surface of said circular-cylindrically-shaped top cap of said hollow canister has a circumferentially-disposed and radially-outwardly-extending flange that extends circumferentially around, and radially outwardly from, a lower open end thereof; said hollow and cylindrically-shaped portion of said center of said inner surface of said circular-cylindrically-shaped top cap of said hollow canister further has a horizontally-outwardly extending inlet tube that extends horizontally outwardly therefrom and is in fluid communication therewith. ### Claim 18 (depends on 17) The system as defined in claim 17, wherein said connecting means includes a substantially Z-shaped conduit that has a lower end that is connected to, and in fluid communication with, said submersible internal pump, and an upper end that passes through said throughbore in said hollow and cylindrically-shaped side of said circular-cylindrically-shaped top cap of said hollow canister, and is sealingly connected to, and in fluid communication with, said horizontally-outwardly extending inlet tube of said hollow and cylindrically-shaped portion of said center of said inner surface of said closed top of said circular-cylindrically-shaped top cap of said hollow canister, so that said submersible internal pump is in fluid communication with said hollow canister. ### Claim 19 (depends on 15) The system as defined in claim 15, wherein said hollow canister further includes a hollow, open-ended, and circular-cylindrically-shaped body that extends vertically downwardly from, in fluid communication with, and is replaceably sealingly positioned at an upper end thereof in, said open bottom of said circular-cylindrically-shaped top cap of said hollow canister; said hollow, open-ended, and circular-cylindrically-shaped body of said hollow canister encases said third filtering stage and said fourth filtering stage; said hollow canister further includes a circular-cylindrically-shaped bottom cap that has a circular-shaped and substantially closed bottom with a pair of spaced-apart drain throughbores extending vertically therethrough, and a circular-shaped open top that is in fluid communication with, and is replaceably sealingly positioned to, a lower end of said hollow, open-ended, and circular-cylindrically-shaped body of said hollow canister. ### Claim 20 (depends on 17) The system as defined in claim 17, wherein said third filtering stage includes a porous polyester draw bag that is removably secured, by a draw string, around said hollow and cylindrically-shaped portion of said center of said inner surface of said circular-shaped closed top of said circular-cylindrically-shaped top cap of said hollow canister and extends vertically downwardly therefrom, with said circumferentially-disposed and radially-outwardly-extending flange of said open lower end of said hollow and cylindrically-shaped portion of said center of said inner surface of said circular-shaped top of said circular-cylindrically-shaped top cap of said hollow canister providing a seal therebetween against leaks, while said draw string of said porous polyester draw bag of said third filtering stage contained in said hollow canister allows for quick and easy replacement thereof. ### Claim 21 (depends on 20) The system as defined in claim 20, wherein said porous polyester draw bag of said third filtering stage contained in said hollow canister is 4" in diameter, 12" in length, and has a porosity in the range of 100-200 microns when the spent petroleum based hydrocarbon fluid is a cleaning solvent, and has a porosity in the range of 50-100 microns when the spent petroleum based hydrocarbon fluid is a blanket wash. ### Claim 22 (depends on 21) The system as defined in claim 21, wherein said porous polyester draw bag of said third filtering stage is 200 microns when the spent petroleum based hydrocarbon fluid is a cleaning solvent, and is 50 microns when the spent petroleum based hydrocarbon fluid is a blanket wash. ### Claim 23 (depends on 20) The system as defined in claim 20, wherein said porous polyester draw bag of said third filtering stage contains charcoal that adsorbs grease and dirt from the spent petroleum based hydrocarbon fluid passing therethrough. ### Claim 24 (depends on 23) The system as defined in claim 23, wherein said charcoal contained in said porous polyester draw bag of said third filtering stage is F-300 mesh made from real coal and not derivatives of a group consisting of coconut and wood. ### Claim 25 (depends on 23) The system as defined in claim 23; further comprising a nylon filter disposed over said lower open end of said hollow and cylindrically-shaped portion of said center of said inner surface of said circular-cylindrically-shaped top cap of said hollow canister, so that a barrier for said charcoal contained in said porous polyester draw bag of said third filtering stage contained in said hollow canister is provided since fluid seeks its own level and when said submersible internal pump is inoperative the spent petroleum based hydrocarbon fluid will return back down through said connecting means and have a tendency to carry with it particles of said charcoal contained in said porous polyester draw bag of said third filtering stage contained in said hollow canister. ### Claim 26 (depends on 20) The system as defined in claim 20, wherein said fourth filtering stage includes a porous polyester draw bag that is contained in the hollow canister and encases said third porous polyester draw bag of said third filtering stage contained in said hollow canister; said porous polyester draw bag of said fourth filtering stage is removably secured, by a draw string, around said hollow and cylindrically-shaped portion of said center of said inner surface of said circular-cylindrically-shaped top cap of said hollow canister and extends vertically downwardly therefrom, with said circumferentially-disposed and radially-outwardly-extending flange of said lower open end of said hollow and cylindrically-shaped portion of said inner surface of said circular-shaped closed top of said circular-cylindrically-shaped top cap of said hollow canister providing a seal therebetween against leaks, while said draw string of said porous polyester draw bag of said fourth filtering stage contained in said hollow canister allows for quick and easy replacement thereof. ### Claim 27 (depends on 26) The system as defined in claim 26, wherein said empty porous polyester draw bag of said fourth filtering stage is 6" in diameter, 18" in length, and has a porosity in the range of 1-100 microns when the spent petroleum based hydrocarbon fluid is a cleaning solvent, and has a porosity in the range of 1-50 microns when the spent petroleum based hydrocarbon fluid is a blanket wash. ### Claim 28 (depends on 27) The system as defined in claim 27, wherein said porosity of said porous polyester draw bag of said fourth filtering stage is 100 microns when the spent petroleum based hydrocarbon fluid is a cleaning solvent, and is 5 microns when the spent petroleum based hydrocarbon fluid is a blanket wash. ### Claim 29 (depends on 26) The system as defined in claim 26, wherein said porous polyester draw bag of said fourth filtering stage contained in said hollow canister contains fuller's earth that adsorbs discoloration from the spent petroleum based hydrocarbon fluid passing therethrough, since fuller's earth is a decolorizer and a bleaching agent. ### Claim 30 A method of using an on-site automated closed loop petroleum based hydrocarbon fluid filtration and recycling system, comprising the steps of: a) passing a spent petroleum based hydrocarbon fluid into an empty porous polyester draw bag of a first filtering stage of said on-site automated closed loop petroleum based hydrocarbon fluid filtration and recycling system, via an inlet throughport in a lid of said on-site automated closed loop petroleum based hydrocarbon fluid filtration and recycling system, where large particles of dirt and grease are removed from the spent petroleum based hydrocarbon fluid passing therethrough; b) passing the spent petroleum based hydrocarbon fluid that previously past through said empty porous polyester draw bag of said first filtering stage into an empty porous polyester draw bag of a second filtering stage of said on-site automated closed loop petroleum based hydrocarbon fluid filtration and recycling system, which encases said empty porous polyester draw bag of said first filtering stage, where small particles of dirt and grease are removed from the spent petroleum based hydrocarbon fluid passing therethrough; c) allowing the spent petroleum based hydrocarbon fluid that previously passed through said empty porous polyester draw bag of said second filtering stage to fall downwardly, by gravity, to a lower portion of a hollow and open-top fluid reservoir of said on-site automated closed loop petroleum based hydrocarbon fluid filtration and recycling system; d) drawing in the spent petroleum based hydrocarbon fluid at said lower portion of said hollow and open-top fluid reservoir into a submersible internal pump; e) pumping the spent petroleum based hydrocarbon fluid upwardly through a substantially Z-shaped internal conduit of said on-site automated closed loop petroleum based hydrocarbon fluid filtration and recycling system; f) passing the spent petroleum based hydrocarbon fluid through a hollow and cylindrically-shaped portion of a circular-cylindrically-shaped top cap of a hollow canister of said on-site automated closed loop petroleum based hydrocarbon fluid filtration and recycling system; g) passing the spent petroleum based hydrocarbon fluid that previously passed through the hollow and cylindrically-shaped portion of said circular-cylindrically-shaped top cap of said hollow canister into a porous polyester draw bag of a third filtering stage contained in said hollow canister where charcoal contained in said porous polyester draw bag of said third filtering stage contained in said hollow canister adsorbs grease and dirt from the spent petroleum based hydrocarbon fluid passing therethrough, while said porous polyester draw bag of said third filtering stage contained in said hollow canister eliminates large particles of dirt and grease from the spent petroleum based hydrocarbon fluid passing therethrough; h) passing the spent petroleum based hydrocarbon fluid that previously passed through said porous polyester draw bag of said third filtering stage through a porous polyester draw bag of a fourth filtering stage where fuller's earth contained in said porous polyester draw bag of said fourth filtering stage contained in said hollow canister adsorbs discoloration from the spent petroleum based hydrocarbon fluid passing therethrough, while said porous polyester draw bag of said fourth filtering stage contained in said hollow canister eliminates small particles of dirt and grease from the spent petroleum based hydrocarbon fluid passing therethrough; i) passing downwardly, by gravity, the recycled petroleum based hydrocarbon fluid that previously passed through said porous polyester draw bag of said fourth filtering stage through a pair of spaced-apart drain throughbores in a circular-shaped and substantially closed bottom of a circular-cylindrically-shaped bottom cap of said hollow canister to said lower portion of said hollow and open-top fluid reservoir; j) repeating steps d)-i) for a time duration controlled by an external timer of said on-site automated closed loop petroleum based hydrocarbon fluid filtration and recycling system; and k) pumping concurrently with step j) the recycled petroleum based hydrocarbon fluid, by an external pump, up through a conduit to a device from which the spent petroleum based hydrocarbon fluid has been recycled for reuse, so that the recycled petroleum based hydrocarbon fluid is dispensed while the spent petroleum based hydrocarbon fluid is simultaneously recycled. ### Claim 31 A method of automatically recycling a spent petroleum based hydrocarbon fluid on-site and simultaneously continuously dispensing on-site a recycled petroleum based hydrocarbon fluid that is the spent petroleum based hydrocarbon after being recycled, comprising the step of passing the spent petroleum based hydrocarbon fluid through an on-site automated closed loop petroleum based hydrocarbon fluid filtration and recycling system which comprises: a) a hollow and open-top fluid reservoir having a closed bottom with an inner surface, and an open top disposed above said closed bottom of said hollow and open-top fluid reservoir; b) a lid having an outer surface, an inner surface, an inlet throughport extending vertically therethrough, an output throughport extending vertically therethrough, and selectively opening and closing said open top of said hollow and open-top fluid reservoir, so that internal components housed in said hollow and open-top fluid reservoir can be readily serviced; c) inlet means for inputting the spent petroleum based hydrocarbon fluid into said hollow and open-top fluid reservoir; said inlet means being disposed in said inlet throughport in said lid; d) outlet means for outputting the recycled petroleum based hydrocarbon fluid from said hollow and open-top fluid reservoir; said outlet means being disposed in said outlet throughport in said lid; e) a first filtering stage contained in said hollow and open-top fluid reservoir and being removably attached to said inlet means; said first filtering stage removing large particles of dirt and grease from the spent petroleum based hydrocarbon fluid passing therethrough; f) a second filtering stage encasing said first filtering stage and being contained in said hollow and open-top fluid reservoir; said second filtering station being removably attached to said inlet means and removing small particles of dirt and grease from the spent petroleum based hydrocarbon fluid passing therethrough; g) a submersible internal pump having an operating time and being disposed in said hollow and open-top fluid reservoir on said inner surface of said closed bottom of said hollow and open-top fluid reservoir, in proximity to said outlet means; said submersible internal pump drawing in the spent petroleum based hydrocarbon fluid passing through said second filtering stage; h) a third filtering stage contained in said hollow and open-top fluid reservoir and being tandemly disposed to said first filtering stage and said second filtering stage; said third filtering stage adsorbing grease and dirt from the spent petroleum based hydrocarbon fluid passing therethrough; i) connecting means for fluidly connecting said submersible internal pump to said third filtering stage and being contained in said hollow and open-top fluid reservoir; said connecting means transporting the spent petroleum based hydrocarbon fluid drawn in by said submersible internal pump to said third filtering stage; and j) a fourth filtering stage encasing said third filtering stage and being contained in said hollow and open-top fluid reservoir; said fourth filtering station removing discoloration from the spent petroleum based hydrocarbon fluid passing therethrough, so that the spent petroleum based hydrocarbon fluid passes downwardly through said first filtering stage and is purged of large particles of dirt and grease, then passes downwardly through said second filtering stage and is purged of small particles of dirt and grease, then is drawn into said submersible internal pump, then is pumped upwardly through said connecting means, then passes downwardly through said third filtering stage and is purged of dirt and grease, then passes downwardly through said fourth filtering stage and is purged of discolorations, then enters into said hollow and open-top fluid reservoir, and then is drawn into said outlet means as the recycled petroleum based hydrocarbon fluid.