Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D41/00—Regeneration of the filtering material or filter elements outside the filter for liquid or gaseous fluids
  • B01D41/04—Regeneration of the filtering material or filter elements outside the filter for liquid or gaseous fluids of rigid self-supporting filtering material
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
  • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
  • F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
  • F01N3/0237—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles for regenerating ex situ

Definitions

• the present invention relates to a method and system for cleaning filters, and in particular filters for exhaust particles from combustion engines, such as diesel particle filters.
• the particle filters are very efficient in collecting particles and many vehicles have a certain cleaning procedure at certain intervals, wherein the filter is heated in order to try and remove the collected particles.
• the filter is heated in order to try and remove the collected particles.
• the replacement of the filter is rather costly for the vehicle owner and the filter should be able to be used further if cleaned because the material of the filter, stainless steel and ceramics, have not been degraded during use, if the filter has not been exposed to physical damage, and thus the filter could be reconditioned. This would in turn mean cheaper spare parts for the owners as well as reduced use of material resources.
• a dry air gun e.g., 50-100 psi
• a source of pressurized air e.g., 50-100 psi
• WO2008091218A1 discloses a method of cleaning a particle filter, in particular for combustion engines, comprising the steps of: - a) applying heat to the interior of the particle filter during a certain time period for burning the trapped particles, - b) removing the burnt particles from the particle filter, - c) measuring the particle filter, wherein the measurements are compared to values of an unused filter of the particular type, and if the measured values deviate from the values of the unused filter by a predetermined amount, steps a) to c) are repeated until the measured values are within an approval range. It is mentioned that the removal of burnt particles is performed by blowing air into the particle filter.
• WO06096244A1 discloses an apparatus for combusting soot from a diesel engine exhaust aftertreatment device.
• the apparatus includes a cabinet having a housing, a heating element positioned within the housing of the cabinet, and a mounting arrangement for securing the diesel engine exhaust aftertreatment device above the heating element.
• the apparatus also includes an ash collection container mounted beneath a floor of the housing for collecting ash that falls from the diesel engine exhaust aftertreatment device during heating.
• EP1698765A1 discloses a pulse cleaner for cleaning a diesel exhaust treatment device.
• the pulse cleaner includes a cabinet, a diesel exhaust treatment device positioned within the cabinet, and a collection filter positioned within the cabinet for collecting material displaced from the diesel exhaust treatment device during cleaning.
• the pulse cleaner also includes a pulse generator for generating pulses that are each directed at a majority of a face of the diesel exhaust treatment device when the diesel exhaust treatment device is mounted at the diesel exhaust treatment device mount.
• the pulse generator includes a pressure tank for accumulating pressurized air, and a valve arrangement that flushes the pressurized air from the tank. A pulse of air for cleaning the diesel exhaust treatment device is generated each time the tank is flushed. What is needed is an improved method for servicing overloaded diesel particle filters or other exhaust aftertreatment devices.
• the present invention solves the above mentioned problems associated with prior art methods of cleaning diesel particle filters. Specifically the present invention provides a method for cleaning a diesel particle filter, in particular for combustion engines, comprising the steps of:
• the flow of hot air is generated by blowing ambient air at a flow between 10 and 100 m 3 /hour through a heating element with an effect of 6-24 kW to increase the temperature of the air to 600 C-700 C;
• the flow of hot air is generated by blowing ambient air at a flow between 30 and 70 m 3 /hour through a heating element with an effect of 9-18 kW.
• the flow of hot air is generated by blowing ambient air at a flow between 40 and 60 m 3 /hour through a heating element with an effect of 10-14 kW.
• the diesel particle filter includes a ceramic substrate having a honey-comb configuration of plugged passages. More preferably the diesel particle filter includes silicon carbide or cordierite. In one embodiment of the present invention the diesel particle filter includes a wire mesh. In a preferred embodiment the diesel particle filter includes corrugated metal foil. In order to establish the flow of hot and cold air a blower is used to blow air through the diesel particle filter.
• Fig. 1 shows a flow chart of the method according to the invention.
• Fig. 2 shows schematically a setup for cleaning particle filters for vehicles according to the present invention.
• the present disclosure relates to a method for efficiently and effectively cleaning diesel particle fi lters (DPF) or other exhaust aftertreatment devices.
• DPF diesel particle fi lters
• I n one em bodiment compressed air is used to back flush collected material (e.g. , soot, ash or other material captured from engine exhaust) from DPF.
• cleaning devices and methods are described primarily with respect to cleaning diesel particulate filters. However, it will be appreciated that the same methods can be used to clean other types of engine exhaust aftertreatment devices as well.
• Other example aftertreatment devices that may require servicing include catalytic converters, lean NOx catalyst devices, selective catalytic reduction (SCR) catalyst devices, lean NOx traps, or other devices for removing pollutants from the exhaust stream.
• the methods and cleaners can also be used to clean other types of filters/treatment devices, and are not limited exclusively to engine exhaust aftertreatment devices.
• Diesel particulate filter substrates can have a variety of known configurations.
• An exemplary configuration includes a monolith ceramic substrate having a "honey-comb" configuration of plugged passages as described in U .S. Patent no.
• the filter substrate can include a catalyst.
• catalysts include precious metals such as platinum, palladium and rhodium, and other types of components such as base metals or zeolites.
• DPF or aftertreatment devices are described as having inlet sides or faces and outlet sides or faces.
• the inlet side or face of an aftertreatment device is the side that faces the incoming flow of exhaust when installed in an exhaust system.
• the inlet side can be referred to as the "dirty” side since it is the side at which material filtered from the exhaust stream collects.
• the outlet side or face of an aftertreatment device is the side that faces away from the incoming flow of exhaust when installed in an exhaust system.
• the outlet side can be referred to as the "clean" side.
• Figure 1 shows a schematic flowchart of the method according to the present invention.
• the particles filter to be cleaned is first visually inspected for visual defects such as cracks, damaged fittings and the like.
• the next step is then to clean the interior of the particle filter. According to the present invention this is performed by burning off the soot and carbon compounds that have been deposited on the filter surfaces.
• the particle filter is cooled with a flow of ambient air and ultimately mounted in an exhaust system of a vehicle.
• the particle filter is connected to a flow of heated air.
• a mass flow controller is arranged to control the air flow.
• the air is preheated before entering the particle filter.
• the particle filter is heated to temperatures above the exothermic reaction of the soot when it is burnt off, but not too high, thereby avoiding damaging the ceramic filter surfaces.
• Temperature sensors are arranged to monitor the temperatures.
• the carbon compounds are burnt off the filter surfaces during which the flow is increased to compensate for thermal buoyancy resulting from heating the particle filter.
• the temperature of the hot air is increased in accordance with a predetermined heating curve, which curve dictates the applied temperature at a given time.
• the end of the process could be performed in a few different ways. The most simple is to end the heating after a predetermined time period, which time period is based on empiric studies of different types of particle filter. Another way is to measure the amount of burnt particles during the heating process.
• the particle filter may be subjected to bursts of air injection through it with certain time intervals. The air bursts cause the burnt particles to be ejected from the filter. The amount of particles could then be used as a measurement of when the burning process can be terminated.
• FIG 2 shows an apparatus (1 ) for cleaning a particle filter (2) according to the present invention.
• the outlet (clean) side of the particle filter is releasibly attached to a pipe (3) comprising a heating element (6).
• the pipe (3) is connected to an air source (5) and a fan (4), where incoming air is heated by the heating element (6) before entering the particle filter (2).
• the air (containing burnt particles) leaving the inlet (dirty) side of the particle filter (2) enters a mixing chamber (7), wherein the air is mixed with (cold) ambient air (9) blown into the apparatus through a second fan (8).
• the mixed air is then forced through a filter (10) before leaving the apparatus (1) as clean air (1 1).

Applications Claiming Priority (1)

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• 2011
  • 2011-10-20 EP EP11874296.4A patent/EP2769061A4/de not_active Withdrawn
  • 2011-10-20 WO PCT/DK2011/050399 patent/WO2013056710A1/en active Application Filing

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