Soot treating apparatus with dust collector

Abstract: A hopper (13) for collecting soot included in the exhaust gasses is disposed on a lower portion of a filter (12). There is a backwashing means for introducing a compressed air into the filter from the exhaust gas-downstream side through an air conduit (14) and dropping the soot deposited in the filter on to the hopper. A combustion pipe (15) is disposed on a lower end of the hopper, and an air nozzle (18a) for supplying a combustion air is disposed in the combustion pipe. A combustion medium (30) which is capable of collecting the soot arriving at the combustion pipe and the burned ashes and of letting the combustion air pass therethrough is inserted detachably into the combustion pipe (15). A heater (16) is disposed around the combustion pipe for burning soot which is collected by the combustion medium. The soot is burned completely at the combustion medium and the ashes remain at the combustion medium. Whereby the combustion gasses can be directly discharged to the atmosphere. The ashes can be easily dumped by renewing the combustion medium itself.

Description: FIELD OF THE INVENTION The present invention relates to a soot treating apparatus with a dust collector, which is capable of collecting soot from exhaust gasses of engines equipped for the performance tests, before the exhaust gasses are discharged to the atmosphere. More particularly, the present invention relates to an apparatus for burning soot collected by the dust collector. A soot treating apparatus with a dust collector of this type is, for example, described in JP 6 317 137. DESCRIPTION OF THE RELATED ART The applicant filed an application for an utility model which is directed to this kind of the soot treating apparatus (Unexamined Published Japanese Utility Model Application No. 5(1993)-30413). As shown in Fig. 2, this apparatus comprises a filter 2 disposed in an exhaust gas duct 1 through which the exhaust gasses pass, and a hopper 3 disposed on a lower portion of the filter 2. A normally-open type damper 1a is disposed in the duct 1 on an inlet side of the filter 2, and a normally-open type damper 1b is disposed in the duct 1 on an outlet side of the filter 2. In the duct 1 on an exhaust gas-downstream side of the filter 2 is disposed a backwashing air conduit 4 for introducing a compressed air thereto, and a normally-closed type valve 4a is disposed in the air conduit 4. A combustion pipe 5 is connected to a lower end of the hopper 3, and a heater 6 is disposed around the combustion pipe 5. A chamber 7 is disposed on a lower end of the combustion pipe 5, and a filter 7a is disposed in the chamber 7. An air blowing pipe 8a is disposed on an upper portion of the combustion pipe 5, and an air blowing pipe 9a is disposed on a lower end of the combustion pipe 5. A blower 8b is connected to the air blowing pipe 8a, and a blower 9b is connected to the air blowing pipe 9a. When the soot is burned by the above-mentioned apparatus, the combustion pipe 5 is heated up by the heater 6. The damper 1b is closed, and the blowers 8b and 9b are operated. After that. the valve 4a is opened only in a short time, then the compressed air is blown against the filter 2 through the air conduit 4. The soot deposited in the filter 2 is dropped on to the hopper 3. The soot deposited on to the hopper 3 is transferred to the combustion pipe 5 by the air blown from the air blowing pipes 8a and 9a, thereby the transferred soot is burned to be made into the ashes. The ashes are collected in the chamber 7, whereby the air including the ashes and blown from the air blowing pipes 8a and 9a are purified by the filter 7a to thereby be discharged to the atmosphere. In the conventional soot treating apparatus with dust collector, the soot dropped from the filter on to the hopper at the time of the backwashing is transferred to the combustion pipe in a short time by the combustion air, then pass through the combustion pipe. As a result, the soot passing therethrough has been hardly burned completely in the combustion pipe. Accordingly, there has been a problem that the combustion pipe must be made long and the heater must be made long along the combustion pipe in order to burn the soot completely, so that the apparatus as a whole excessively becomes large-sized. Also, in the above-mentioned apparatus, it has been troublesome to take out the ashes collected in the chamber therefrom, or to clean or renew the filter to which the ashes adhere. In JP 62 080 416 a ceramic burner element and in EP 0 327 653 a soot-filter are described. SUMMARY OF THE INVENTION It is, therefore, an object of the invention to provide a small-sized soot treating apparatus with a dust collector, which is capable of burning effectively the soot dropping from a filter, in a short combustion pipe, to thereby make all the soot into ashes. It is, another object of the invention to provide a soot treating apparatus with a dust collector, which is capable of discharging the combustion gasses directly to the atmosphere, and dumping the ashes easily. It is still another object of the invention to provide a soot treating apparatus with a dust collector, which is capable of using effectively the thermal energy of the heater as the preheating of the combustion air. These objects are achieved according to the invention by a soot treating apparatus with a dust collector as defined in claim 1. Further preferred embodiments of the invention are defined in the dependend claims. The invention according to claim 1 is, as shown in Fig. 1, directed to a soot treating apparatus with a dust collector, comprising a filter 12 disposed on a passage 11 through which exhaust gasses pass for collecting soot included in the exhaust gasses, a hopper 13 disposed on a lower portion of the filter 12, a backwashing means for introducing a compressed air into the filter through an exhaust gas-downstream side of the filter 12 to drop the soot deposited in the filter 12 on to the hopper 13, a combustion pipe 15 connected to a lower end of the hopper 13, an air supplying means for supplying a combustion air into the combustion pipe 15, and a heater 16 disposed around the combustion pipe 15, wherein a combustion means 30 detachably inserted into the combustion pipe 15, which is capable of collecting the soot 10 arriving at the combustion pipe 15 and the burned ashes and of letting the combustion air pass therethrough, and the heater 16 is adapted to burn the soot collected by the combustion means. When the soot is burned to be treated, the soot deposited in the filter 12 by introducing the compressed air thereto by the air conduit 14 is dropped on to the hopper 13. The soot is adhered to the combustion means 30 due to the combustion air supplied to the combustion pipe 15, and burned due to the heat of the heater 16. The ashes generated due to the combustion remain in the combustion means 30. A clean air passing through the combustion means 30, which does not include the soot or the ashes, is discharged to the atmosphere. When the ability in which the combustion means 30 can collects the soot or the ashes is lowered, the combustion means 30 is renewed. According to a preferred embodiment a heat exchanger 17 is disposed around the heater 16, and the air supplying means is comprised of an air supplying blower 18b, an air nozzle 18a for jetting an air toward the combustion means 30 from a side of the hopper, and an air pipe passage 18c disposed so as to pass through the heat exchanger 17 for connecting the blower 18b and the air nozzle 18a to each other. The air pipe passage 18c is warmed up by the heat exchanger 17 by using the heat of the heater 16 effectively. The combustion air is warmed through the air pipe 18c to be jetted from the air nozzle 18a as the warm wind. Whereby, the combustion efficiency of the soot at the combustion means 30 is improved. In a further preferred embodiment the combustion means 30 is comprised of heat-resistant porous ceramic having pores of average diameter from 20 to 700 µm. As porous ceramic, there are exemplified alumina and cordierite, etc., which are greater in heat-resistance. It is preferable that porous ceramic is of a pellet-like one or a chip-like one which is greater in specific surface area. Otherwise, porous ceramic may be of a honeycomb-like one. The former pellet-like or chip-like porous ceramic has preferably pores of average diameter from 50 to 150 µ m, more preferably 100 µ m. The latter honeycomb-like porous ceramic has preferably pores of average diameter from 400 to 600 µ m, more preferably 500 µ m. According to another preferred embodiment the combustion means 30 is arranged on a plate 31 fixed to the combustion pipe 15 so as to cross with the combustion pipe 15, and the plate 31 is comprised of heat-resistant porous ceramic having pores of average diameter from 300 to 700 µ m, and is capable of collecting the soot 10 and the burned ashes and of letting the combustion air pass therethrough. This plate 31 is comprised of porous ceramic, average diameter of which is preferably 400 to 600 µ m, more preferably 500 µ m. The plate 31 prevents the soot deposited in the combustion pipe 15 of the combustion means 30 from dropping from the combustion pipe 15, and is capable of letting the combusting air pass therethrough. The plate 31 has a function of collecting the ashes which come from the combustion medium 30 after the combustion. As described above, according to the invention, the soot which is dropped from the filter can be burned effectively by the short combustion pipe, so that all the soot can be made into the ashes. As a result, the ashes are less in harm compared with the soot, then the volume thereof becomes 1/100 of the soot. Since the ashes are remained in the combustion medium, the combustion gasses can be directly discharged to the atmosphere. Also, the ashes can be dumped easily by renewing the combustion means itself. Also, the combustion efficiency of the soot can be improved by using effectively the thermal energy of the heater as the preheating of the combustion air. Further advantages of the invention will be apparent from the following description of the preferred embodiment of the invention as illustrated in the accompanying drawing. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a constructional view of a soot treating apparatus with a dust collector according to the invention; and Fig. 2 is a constructional view of a conventional soot treating apparatus with a dust collector, which corresponding to that of Fig. 1. DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the invention will be described hereinafter with reference to the drawing. As shown in Fig. 1, there are equipped a plurality of diesel engines 21, 22, and 23 for the performance tests. Exhaust gas pipes 21b, 22b and 23b are connected to exhaust manifolds 21a, 22a and 23a of these engines 21, 22 and 23. The exhaust gas pipes 21b, 22b and 23b are connected to the exhaust gas duct 11 through exhaust gas ducts 24 and 25. A filter 12 is disposed on an intermediate portion of the exhaust gas duct 11. The filter 12 is made of porous ceramic, which is adapted to collect the soot included in the exhaust gasses of the engines 21 to 23. A normally-open type damper 11a which adjusts the inflow amount of the exhaust gasses to the filter 12 and a normally-open type damper 11b which adjusts the outflow amount of the exhaust gasses from the filter 12 are disposed on the exhaust gas duct 11, respectively. On the exhaust gas duct 11 between the filter 12 and the damper 11b is disposed a back-washing air conduit 14 for introducing a compressed air thereinto, and a normally-closed valve 14a is disposed on the air conduit 14. A suction fan 29 is connected to the exhaust gas duct 11 having the damper 11b, through the exhaust gas ducts 26, 27 and 28. A hopper 13 is disposed on a lower portion of the filter 12. An upper end of the combustion pipe 15 extending vertically is connected to a lower end of the hopper 13, and a lower end of the combustion pipe 15 is connected to an exhaust gas duct 28. The combustion means 30 is inserted into the combustion pipe 15. An air nozzle 18a for jetting the combustion air toward the combustion means 30 is disposed in the combustion pipe 15 which is arranged on an upper portion of the combustion medium 30. The combustion means 30 is capable of collecting the soot which arrives at the combustion pipe 15 and the burned ashes, and is comprised of heat-resistant porous ceramic having pores of average diameter of 100 µ m. In this embodiment, the combustion means 30 is inserted thereinto in a pellet-like condition in order to increase the specific surface area. The pellet is formed in a column body having diameter of 5 mm and length of 5 mm, for example. This combustion means 30 is arranged on a disk-like plate 31 having thickness of 5 mm, which is inserted into and fixed to the combustion pipe 15. This plate 31 is comprised of porous ceramic having pores of average diameter of 500 µ m. A heater 16 is disposed around the combustion pipe 15, and is adapted to burn the soot collected by the combustion means 30. In this embodiment, temperature of the heater 16 is set to a range of 800 to 900 °C. There is provided a blower 18b for supplying an air to the above-mentioned air nozzle 18a. A heat exchanger 17 is disposed around the heater 16. In the heat exchanger 17 an air pipe passage 18c is spirally disposed in glass wool. The blower 18b and the air nozzle 18a are connected to each other through the air pipe passage 18c. According to the soot treating apparatus with the dust collector constructed above, the exhaust gasses of the diesel engines 21 to 23 flow into the filter 12 through the exhaust gas ducts 24 and 25 by the operation of the suction fan 29, where the soot included in the exhaust gasses are collected. Clean gasses passing through the filter 12 are discharged to the atmosphere through the exhaust gas ducts 11, 26, 27 and 28. When the soot collected by the filter 12 is burned, a switch of the heater 16 is turned on to be heated up to 800 to 900 °C. Next, the blower 18b is operated and the warm wind is blown against the combustion means 30 through the air nozzle 18a, simultaneously the damper 11b is closed. After the damper 11b is closed, the valve 14a is opened in a short time, so that the compressed air is introduced through the air conduit 14. Whereby, the compressed air is blown against the -filter 12, then the soot deposited in the filter 12 is dropped on to the hopper 13. The dropped soot 10 arrives at the combustion means 30 easily by the warm wind jetted from the air nozzle 18a. Then the soot is collected by the combustion means 30 which is heated by the heater 16, and burned there. The ashes generated due to the combustion remain at the combustion means 30. The air which has burned the soot passes through the combustion means 30 and the plate 31 to reach the exhaust gas duct 28, and then discharged to the atmosphere together with the other exhaust gasses. In a case where the above-operation is carried out repeatedly, then at least one of the combustion means 30 and the plate 31 are blinded, the combustion means 30 or the plate 31 is renewed.

Claims: A soot treating apparatus with a dust collector, the soot treating apparatus comprising a filter (12) disposed on a passage (11) through which exhaust gasses pass for collecting soot included in the exhaust gasses, a hopper (13) disposed on a lower portion of the filter (12), a backwashing means (14) for introducing a compressed air into the filter (12) through an exhaust gas-downstream side of the filter (12) to drop the soot deposited in the filter (12) onto the hopper (13), a combustion pipe (15) connected to a lower end of the hopper (13), an air supplying means (18a, 18b, 18c) for supplying a combustion air into the combustion pipe (15), a heater (16) disposed around the combustion pipe (15), being adapted to burn the soot collected by a combustion means (30), and a heat exchanger (17) disposed around the heater (16), and wherein the dust collector is comprising said combustion means (30) inserted into the combustion pipe (15), which is capable of collecting the soot (10) arriving at the combustion pipe (15) and a part of the burned ashes, and of letting the combustion air pass therethrough, and a plate (31) which is capable of collecting the remaining part of the burned ashes and of letting the combustion air pass therethrough, characterized in that said combustion means (30) is arranged on said plate (31), said plate (31) being renewably fixed to the gas-downstream end of the combustion pipe (15) directly after the combustion means (30) so as to cross with said combustion pipe (15) and being of heat-resistant porous ceramic having pores of average diameter from 300 to 700 µ m. A soot treating apparatus as claimed in claim 1, wherein said combustion means (30) is of heat-resistant porous ceramic having pores of average diameter from 20 to 700 µ m. A soot treating apparatus as claimed in one of the preceding claims, wherein the combustion means (30) is detachably arranged on said plate (31). A soot treating apparatus as claimed in one of the preceding claims characterized in that said air supplying means being comprised of an air supplying blower (18b), an air nozzle (18a) for jetting an air toward the combustion means (30) from a gas-upstream end of the combustion pipe (15), and an air pipe passage (18c) disposed so as to pass through said heat exchanger (17) which is disposed around the heater (16), for connecting the blower (18b) and the air nozzle (18a) to each other.

Inventors: ICHIKAWA JUN, IGARASHI TOSHIO, ICHIKAWA, JUN, IGARASHI, TOSHIO
Applicants: HINO MOTORS LTD, HINO MOTORS, LTD.
Application year: 1996
Main classification: F01N3
IPC codes: F01N3, F23G5, B01D46