Diesel exhaust particulate collectors

Abstract

An apparatus and method for cleaning ash/soot and other particulates from diesel particulate filters (DPF), including diesel oxidative catalysts (DOC) and similar exhaust components. Section for dry and wet cleaning include conduits that connect to the filters. For dry cleaning, a filter is mounted clean side up and air pressure is applied in opposite directions so that the particulate is dislodged and falls out. For wet cleaning, the filter is floated with a slug of liquid cleaning solution which is surged back-and-forth through the filter to dislodge and remove the particulate. The dry and wet cleaning sections may be combined or collocated, or may be located separately or used one without the other.

Claims

1. An apparatus for cleaning a diesel particulate filter having a dirty side directed towards an incoming flow of exhaust and a clean side directed towards an outgoing flow of exhaust, said apparatus comprising: a dry cleaning system that employs a gas to clean particulate from said filter, said dry cleaning system comprising: a first gas supply conduit that is mountable in fluid communication with said clean side of said filter; a second gas supply conduit that is mountable in fluid communication with said dirty side of said filter; and a pressure mechanism that applies pulses of said gas alternatingly against said clean and dirty sides of said filter through said first and second gas supply conduits; and a wet cleaning system that employs a liquid to remove particulate from said filter, said wet cleaning system comprising: a first liquid supply conduit that is mountable in fluid communication to said clean side of said filter; a second liquid supply conduit that is mountable in fluid communication to said dirty side of said filter; and a pump mechanism that surges a slug of said liquid through said filter alternatingly from said clean and dirty sides of said filter through said first and second liquid supply conduits.

2. The apparatus of claim 1, wherein said pressure mechanism comprises: a source of a compressed gas; and a valve mechanism that alternately supplies said compressed gas from said source to said first and second gas supply conduits.

3. The apparatus of claim 1, wherein said dry cleaning system further comprises: connector members that connect said first and second gas supply conduits to said filter with said clean side of said filter oriented generally upwardly and said dirty side of said filter oriented generally downwardly so that gravity aids in removing particulate from said filter.

4. The apparatus of claim 3, wherein said dry cleaning system further comprises: a dust collection bucket mounted in said second gas supply conduit generally below said filter, that collects said particulate removed from said filter.

5. The apparatus of claim 1, wherein said dry cleaning system further comprises: at least one sensor that measures a pressure differential between said dirty and clean sides of said filter to assess a status of said filter.

6. The apparatus of claim 1, wherein said pump mechanism of said wet cleaning system comprises: a pressure mechanism that applies a gas at alternating pressures to opposite sides of said slug of said liquid through said first and second liquid supply conduits.

7. The apparatus of claim 1, wherein said pump mechanism of said wet cleaning system comprises: at least one hydraulic ram mechanism that alternatingly applies pressure to said slug of said liquid in opposite directions through said first and second liquid supply lines.

8. The apparatus of claim 5, wherein said wet cleaning system further comprise: at least one liquid particulate filter in communication with one of said first and second liquid supply conduits, that collects particulate material dislodged from said diesel particulate filter.

9. The apparatus of claim 1, further comprising: a cabinet assembly having said dry cleaning system and wet cleaning system mounted together therein.

10. An apparatus for cleaning a diesel particulate filter having a dirty side directed towards an incoming flow of exhaust and a clean side directed towards an outgoing flow of exhaust, said apparatus comprising: a wet cleaning system that employs a liquid to remove particulate from said filter, said wet cleaning system comprising: a first liquid supply conduit that is mountable in fluid communication to said clean side of said filter; a second liquid supply conduit that is mountable in fluid communication to said dirty side of said filter; and a pump mechanism that surges a slug of said liquid through said filter alternatingly from said clean and dirty sides of said filter through said first and second liquid supply conduits.

11. The apparatus of claim 10, wherein said pump mechanism of said wet cleaning system comprises: a pressure mechanism that alternately applies a pressurized gas to said first and second liquid supply conduits on opposite sides of said slug of liquid.

12. The apparatus of claim 11, wherein said mechanism comprises: a pump mechanism that alternately applies pressure in positive inverse directions to at least one end of said slug of liquid.

13. The apparatus of claim 12, wherein said pumping mechanism comprises: at least one hydraulic ram mechanism mounted in fluid communication with one of said first and second liquid supply conduits.

14. The apparatus of claim 13, wherein said wet cleaning system further comprises: at least one liquid particulate filter in communication with one of said first and second liquid supply conduits that collects particulate material sloshed from said diesel particulate filter.

15. A method for cleaning a diesel particulate filter having a dirty side directed towards an incoming flow of exhaust and a clean side directed towards an outgoing flow of exhaust, said method comprising the steps of: drying cleaning said filter by employing a gas to clean particulate from said filter, the step of dry cleaning said filter comprising: mounting said clean side of said filter in fluid communication with a first gas supply conduit; mounting said dirty side of said filter in fluid communication with a second gas supply conduit; and alternatingly applying pressurized pulses of said gas against said clean and dirty sides of said filter through said first and second supply conduits; and wet cleaning said filter employing a liquid that removes particulate from said filter, the step of wet cleaning said filter comprising: mounting said clean side of said filter in fluid communication with a first liquid supply conduit; mounting said dirty side of said filter in fluid communication with a second liquid supply conduit; and surging a slug of said liquid through said filter alternatingly from said clean and dirty sides of said filter through said first and second liquid supply conduits.

16. The method of claim 15, wherein the step of alternatingly applying pulses of said gas against said clean and dirty sides of said filter comprises: alternatingly supplying a compressed gas from a source to said first and second gas supply conduits.

17. The method of claim 15, wherein the step of drying cleaning said filter further comprises: connecting said first and second gas supply conduits to said filter with said clean side of said filter oriented generally upwardly and said dirty side of said filter oriented generally downwardly, so that gravity aids in removing particulate from said filter.

18. The method of claim 17, wherein the step of cleaning said filter further comprises: collecting said particulate removed from said filter in a dust collection bucket mounted in said second gas supply conduit generally below said filter.

19. The method of claim 15, further comprising: measuring a pressure differential between said dirty and clean sides of said filter to assess a status of said filter.

20. The method of claim 15, wherein the step of surging said slug of said liquid through said filter comprises: applying a gas at alternating pressures to said sides of said slug of said liquid through said first and second liquid supply conduits.

21. The method of claim 15, wherein the step of surging said slug of said liquid through said filter comprises: operating at least one hydraulic ram to alternatingly apply pressure to said slug of said liquid in opposite directions through said first and second liquid supply lines.

22. A method for cleaning a diesel particulate filter having a dirty side directed towards an incoming flow of exhaust and a clean side directed towards an outgoing flow of exhaust, said method comprising the steps of: drying cleaning said filter by employing a gas to clean particulate from said filter, the step of dry cleaning said filter comprising: mounting said clean side of said filter in fluid communication with a first gas supply conduit; mounting said dirty side of said filter in fluid communication with a second gas supply conduit; and alternatingly applying pressurized pulses of said gas against said clean and dirty sides of said filter through said first and second supply conduits.

23. The method of claim 22, further comprising: measuring a pressure differential of said gas between said dirty and clean sides of said filter to assess a status of said filter.

24. (canceled)

25. A method for cleaning a diesel particulate filter having a dirty side directed towards an incoming flow of exhaust and a clean side directed towards an outgoing flow of exhaust, said method comprising the steps of: wet cleaning said filter employing a liquid that removes particulate from said filter, the step of wet cleaning said filter comprising: mounting said clean side of said filter in fluid communication with a first liquid supply conduit; mounting said dirty side of said filter in fluid communication with a second liquid supply conduit; and surging a slug of said liquid through said filter alternatingly from said clean and dirty sides of said filter through said first and second liquid supply conduits.

26. The method of claim 25, wherein the step of surging said slug of said liquid through said filter comprises: applying a gas at alternating pressures to opposite sides of said slug of said liquid through said first and second liquid supply conduits.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is a front perspective view of a combination dry/gas and wet/liquid filter cleaning system in accordance with the present invention, with first and second DPFs connected for cleaning in the dry and wet sides of the system being visible through windows in doors at the front of the assembly;

[0027] FIG. 2 is a front perspective view of the system of FIG. 1 with the front panels and doors removed, showing in greater detail the two DPFs and the wet and dry cleaning systems that are connected thereto;

[0028] FIG. 3 is an enlarged perspective view of the filter undergoing cleaning on the wet/liquid side of the system of FIGS. 1-3, the filter being shown partly cut away to reveal the filter body and other internal aspects of the DPF;

[0029] FIG. 4 is a second enlarged perspective view of the connected DPF of FIG. 3, showing the manner in which a mass of water is surged back and forth through the body of the filter; and

[0030] FIG. 5 is a rear perspective view of the combination dry and wet filter cleaning system of FIG. 1.

DETAILED DESCRIPTION

[0031] FIG. 1 shows a filter cleaning system 10 in accordance with a preferred embodiment of the present invention. The illustrated embodiment includes both a dry cleaning section 12 that employs air or other gas to clean the filter and a wet cleaning section 14 that employs water or other liquid, which enhances efficiency and speeds workflow, however it will be understood that the dry cleaning and wet cleaning sections may be installed or used separately or one without the other.

[0032] As can be seen with further reference to FIG. 1, each of the cleaning sections 12, 14 includes a cleaning chamber in which are placed the filters 16 being cleaned, and which are accessed at the front of the assembly via doors optionally having windows through which an operator can observe the filters and associated fittings during the cleaning process.

[0033] As will be described in greater detail below, the dry cleaning section provides cleaning of the filters using air or other gas as a fluid, and collection of the dislodged dust from the flow of gas, and also provides a differential pressure test to check cleaning progress and filter integrity, while the wet cleaning section provides cleaning of the filters using water or other liquid as the fluid and filtration of the liquid to remove the dislodged particulate.

[0034] As will be described in greater detail below, the dry cleaning section provides cleaning of the filters using air or other gas as the fluid, and collection of the dislodged dust from the flow of gas, and may also provide a differential pressure test to check cleaning progress and filter integrity, while the wet cleaning section provides cleaning of the filters using water or other liquid as the fluid, and filtration of the liquid to remove the dislodged particulate. In the following description, unless otherwise distinguished, the term air includes atmospheric air as well as other gasses, and the term water includes ordinary tap water, as well as aqueous and non-aqueous solutions and other liquids.

[0035] a. Dry Cleaning Section

[0036] As can be seen in FIG. 2, the dry cleaning section 12 includes a cabinet 22 having a door 18 that provides access to a cleaning chamber 24 in which the filter 16 while it is cleaned. The latter filter is preferably installed in a generally vertical orientation as shown with the intake dirty side down and the outlet clean side up so that gravity aids in removing the dislodged particulate. For purposes of illustration the filters are shown partially cutaway to reveal the filter body 26 contained within a metal housing 28, as is typical of DPFs employed for road-going vehicles, for example. The intake and outlet pipes 30, 32 are aligned generally vertically and are connected to gas supply conduits in the form of air pipes 34, 36, suitably by adaptors and quick-connect fittings 40 at the ends.

[0037] Air pressure is supplied to connector lines 34, 36 from reservoir tanks 42, 44 at the rear of the cabinet (see FIG. 5) via solenoid valves 46, 48; the reservoir pipes 42, 44 are filled with high pressure air from a compressor or other suitable source (not shown), which is released as comparatively high pressure pulses via lines 34, 36 when the solenoid valves are opened. The reservoir tanks may suitably be formed of lengths of 3 diameter pipe, for example. A second reservoir tank 50 and a solenoid valve 52 are similarly installed on the backside of the wet cleaning section, for use as will be described below.

[0038] Therefore, when solenoid valve 48 is opened, a pulse of pressurized air is directed through line 36 against the outlet or clean side of the filter 16, forcing air through the medium of the filter and dislodging accumulated particulate material from the downwardly facing dirty side. The particulate material drops through the intake pipe 30 of the filter and through line 34 into a collection bucket 54 having a window 56 that is open to view at the front of the assembly so that the operator can visually check the amount of material that has been removed. After one or more pulses in the first direction, one or more pulses in the opposite, reverse direction may be applied to the filter by opening the other solenoid valve 46 so that the pulses impinge on the inlet dirty side of the filter body to aid in loosening and freeing the deposits.

[0039] One example sequence for cleaning a filter using the dry cleaning section is as follows, it being understood that the example is provided by way of illustration rather than limitation and that the steps may vary depending on embodiment and circumstances, such as filer type, size and condition, for example: [0040] a. Apply 3-5 pulses of air to the clean end. The pressure, duration and number of pulses (1 or more) may be varied as needed. [0041] b. Apply 1-2 pulses of air to the dirty end. Again, the pressure, duration and number of pulses may be varied as needed. [0042] c. During application of the pulses to the clean end (outlet) of the DPF, soot and ash are blown out of the filter. This may be observed by an operator to assess cleanliness and/or integrity of the filer; optionally a particulate sensor may monitor the soot and ash blown out of the filter in place of or in addition to use of the viewing area. [0043] d. During application of the pulses to the dirty end (inlet) of the DPF, the air that passes through and out of the clean end (outlet) of the filter may be monitored by a sensor that measures particulate carried by the flow. [0044] e. Steps a-d may be repeated as necessary until no more soot or ash is observed/measured in steps c/d.

[0045] After or during the cleaning sequence, a differential pressure measurement may be taken to measure how effectively the DPF has been cleaned. A flow of air is supplied from a blower 60 or other suitable source via lines 62 and 34 and passed through the body 26 of the filter at a measured volume and/or pressure. The differential pressure is measured across the DPF and compared to reference values for a new filter. The effectiveness of the cleaning may be graded based on the comparison of the measured and reference differentials, to determine whether the filter has been adequately cleaned for return to service or additional cleaning is needed. The comparison can also be used as a test of filter integrity, with failure/damage indicated by a differential less than that of a new filter.

[0046] Particulate that has been dislodged from the intake dirty side of the DPF and collected in bucket 54 may be drawn off through a suction line 64 by a fan 66 at the upper end of a dust collector 68. Similarly, material that has been dislodged from the outlet clean side of the filter can be drawn off via a suction line 70, that is connected to the upper line 36 at a T 72. The dust collector can therefore also take a suction on either end of the filter; for example, when pulsing the filter on the clean end, the dust collector may draw a suction on the dirty end and vice versa.

[0047] Dust collector 68 may include an internal pulse line that is located within the primary filter, to facilitate removal of soot/ash from the latter. The dislodged soot and ash fall to the bottom of the dust collector for removal, e.g., via a bucket or an external vacuum source.

[0048] b. Wet Cleaning Section

[0049] Similar to the dry cleaning section described above, the wet cleaning section 14 includes a cabinet 80 having a chamber 82 that encloses the filter 16 and that is accessible via a door 18 at the front. First and second fluid lines 84 and 86 form liquid supply conduits. The first line 84 is connected to the outlet pipe 32 on the clean side of the filter, using an adaptor and quick-connect coupler 40, for example, and the second line 86 is similarly connected to the inlet pipe on the dirty side of the filter. Water is supplied to a mixing and recirculation tank 88 from a tap or other source via line 90, and may be mixed with chemical additives to form liquid cleaning solution as desired; tank 88 may incorporate a heater for heating the solution to increase its cleaning effectiveness.

[0050] From tank 88 the solution is pumped to a primary solution tank 92 that is located on the upper part of the assembly, above the level of the DPF/DOC that is being cleaned. Upon opening a valve, the solution flows from tank 92 down through lines 94 and 84, so as to fill a volume above the body of the filter with a solid mass or slug of liquid. Air pressure is then applied to the top of the slug from reservoir 50 (see FIG. 5) by opening solenoid valve 52, generating a downward pressure that works in conjunction with gravity to force the liquid solution through the medium of the filter body. As this is done, the liquid flow dislodges the particulate from the filter, so that the dislodged material passes down through the intake pipe of the filter and into line 86, along with the liquid that has flowed through the filter. With continued flow, the upper surface 96 of the slug 98 may reach the body 26 of the filter so that the pressurized air follows the liquid into the filter medium, depending on the intended cleaning cycle.

[0051] From line 86, the liquid solution flows generally horizontally and then vertically through upwardly leading line 100 to a pressurized storage tank 102 at its upper end. The pressurized tank holds a volume of the fluid, with a pressurized blanket of the air or other gas at the top. Particulate material that was dislodged from the filter and carried through line 86 is drawn off and extracted by a liquid particulate filter 104, being circulated back to tank 88. The particulate material collected by filter 104 is in turn discharged to a sediment collection tank 106 for subsequent disposal. Any liquid that spills in chamber 82 is similarly collected in tank 106, via a drain opening 108 and a sluice bucket 110.

[0052] The liquid filtration system using filter 104 may also be used to perform processing of cleaning solutions, to remove soot, ash and other particulates, particularly if multiple solutions are used and it is desirable to keep spent solutions separated. For standalone operations, the system may in addition employ an initial settling tank to allow gravitational removal of heavy solids, and one or more filters to remove additional soot and ash as well as chemical treatment to change solution chemistry.

[0053] As noted above, the liquid solution that has passed through the DPF to the dirty side of the filter accumulates under pressure in line 100 and tank 102. Thus, by realigning the valves of the system the liquid solution can be driven in a reverse direction from the dirty side back towards the clean side of the filter, after which the sequence may be repeated. It has been found that thus working the liquid solution back-and-forth through the medium of the filter with a surging or plunging action is highly effective at removing the deposits.

[0054] The steps in an example cleaning cycle using the wet cleaning section are set forth below: [0055] (1) The DPF is installed in the wet cleaning chamber using the fluid connections, preferably with this clean side oriented upwardly. [0056] (2) A pressure test may be performed to check for leaks. [0057] (3) If the filter was not previously cleaned using the dry system, a pre-cleaning differential pressure measurement may be taken. [0058] (4) The DPF is filled with heated cleaning solution. Extra solution is loaded into the conduit system to form a liquid slug, preferably sufficient to extend beyond the inlet and outlet of the DPF. [0059] (5) The slug of solution is surged back and forth through the filter, in a manner described below. Pressurized air is applied on top of the slug of cleaning solution, from the plumbing that is connected to the outlet (clean end) of the DPF. The air pressure and duration of application are variable. At the same time, a vent valve is opened on the plumbing connected to the inlet (dirty end) of the DPF. Due to the force of the pressurized air, the cleaning solution moves through the DPF from the outlet towards the inlet, removing soot and/or ash in the process. In place of or addition to pressurized air/gas other embodiments may employ other mechanisms to surge the slug back-and-forth, such as one or more hydraulic rams/pistons that act directly or indirectly on the liquid of the slug, for example. [0060] (7) Soot and ash that have been removed from the DPF settle into a trap at a Tee in the plumbing on the inlet side of the filer. [0061] (8) The pressure and vent valves are turned off. [0062] (9) Pressurized air is next applied to the opposite side of the slug of cleaning solution, from the plumbing connected to the inlet (dirty end) of the DPF. The pressure and duration of application are again variable. At the same time, a vent valve is opened on the plumbing connected to the outlet (clean end) of the DPF. Due to the force of the pressurized air, the slug of cleaning solution moves in a reverse direction through the DPF, from the outlet end towards the inlet end of the filter. The pressure applied in this second direction is preferably significantly less than the pressure used in the first, primary cleaning direction, so as to move the liquid slowly back to the outlet side of the filter in preparation for another cleaning cycle without driving ash and soot back into the DPF. [0063] (10) When the cleaning solution reaches a predetermined level as measured in the plumbing attached to the outlet side of the DPF, the air pressure and vent valves are closed. [0064] (11) Cleaning cycle steps 6-10, pushing the slug of liquid back-and-forth through the filter, may be repeated as few or many times as needed. After repeating steps for the necessary number of cycles 6-10, the following steps 12-14 may optionally be performed: [0065] (12) Pressurized air is applied on top of the cleaning solution from the plumbing connected to the outlet (clean end) of the DPF. The air pressure and duration of application may be varied as needed. [0066] (13) A drain valve is temporarily opened below the trap or Tee described in step 7. Soot, ash and solution are removed and sent to the filtration system through a viewing chamber or tube that allows the soot/ash/solution mixture to be viewed by an operator. The DPF is not completely drained of cleaning solution. [0067] (14) Additional solution is loaded at the outlet end of the DPF to make up for the volume removed in step 15. These amounts may or may not be equal. [0068] (15) Cleaning cycle steps 6-14 may be repeated until soot and/or ash are no longer observed coming out of the DPF via the viewing tube/chamber. Manual viewing of the particulate soot/ash and cleaning solution discharged from the filter may be augmented or replaced by use of a sensor mechanism that monitors levels of the material particulate in the flow.

[0069] After the wet cleaning process has been completed, the filter may be dried, for example, by the following steps: [0070] (16) All remaining soot, ash and cleaning solution are drained from the DPF and the connected plumbing. [0071] (17) Pressurized air is applied to the DPF via the plumbing connected to the outlet (clean) end of the filter. The pressure and volume of air may be varied as needed. [0072] (18) A valve in the plumbing connected to the inlet (dirty) end of the DPF is opened to the wet cleaning chamber. A vapor capture system (e.g., a spin-down charcoal filer or similar device) may also be attached to the wet cleaning chamber. [0073] (19) The pressurized air applied to the clean end of the filter blows the cleaning solution out of the filter through the dirty end and into the cleaning cabinet, from which the liquid then drains. [0074] (20) Steam and water droplets condense and fall out in the expanded volume of the cleaning chamber. The resulting reduced moisture air is vented from the cleaning chamber, for example, via the attached vapor capture system. Dry air exiting the vapor capture system can be additionally filtered if needed. [0075] (21) Additionally, the clean, dry air discharged from the cleaning system may be HEPA filtered before being vented into the operator space or outside as desired. [0076] (22) Drying a final differential air pressure measurement may be performed to check cleanliness/integrity of the filter.

[0077] c. Control System

[0078] Operation of the cleaning system may be controlled by a PLC or similar computer system. The operator may, for example, input the DPF part number, serial number and/or other data into the control system at the beginning of the cleaning cycle. The control system may indicate operational status and may provide the operator with readings and warnings, using a display or indicators, for example, and may also send cleaning data to external computers or databases.

[0079] The dry and wet cleaning sections may have individual controls and may be able to operate simultaneously using shared components. When the dry and wet sections both need to access a shared component, the first one to need it may have use of the shared component while the other side may enter a wait cycle until the shared component becomes available for its use in turn. Simultaneous operation may then resume and continue.

[0080] It will be understood that the scope of the appended claims should not be limited by particular embodiments set forth herein, but should be construed in a manner consistent with the specification as a whole.