Background Art As well known to those skilled in the art, domestic and industrial inflammable waste is largely destroyed by fire from the view point of economy. On the other hand, food waste is crushed and dried so that it can be used as a raw material for animal feeds or fertilizers. A great quantity of waste gas, which is generated when the aforesaid various kinds of waste are treated, is very harmful to human beings. Moreover, the environment is polluted if the waste gas is directly discharged to the atmosphere.

Accordingly, it is required that the waste gas should undergo a process for lowering the content of the toxic components in the waste gas to below a permitted concentration before it is discharged to the atmosphere.

Up to now, the toxic components in the waste gas produced at the time of waste treatment have been removed by a purification facility which makes use of a combination of various kinds of apparata, such as an adsorption filter, an electric dust collector, a wet-type gas scrubber, and various kinds of methods. However, the waste gas purification facility has a disadvantage in that its efficiency is too low to eliminate dioxin, volatile organic compounds (VOC), and malodorous components contained in the waste gas. Furthermore, the waste gas purification facility is large in scale, which means that an extensive site for installation of the waste gas purification facility is required and that the cost for installation of the waste gas purification facility is high. Moreover, the aforesaid adsorption filter, which is very expensive, must be periodically replaced, and the aforesaid wet-type gas scrubber uses a large quantity of water. Consequently, it is very difficult to control and maintain the waste gas purification facility, which increases the cost for operating the waste gas purification facility.

Disclosure of the Invention Therefore, in view of the above-noted problems, it is an object of the

present invention to provide a waste gas purifier which is simple in structure and capable of efficiently eliminating toxic and malodorous components from waste gas.

In accordance with the present invention, there is provided a waste gas purifier comprising: a tank having a water storage chamber for storing water and an air outlet port formed at the top of the water storage chamber; a gas inlet conduit for introducing waste gas into the tank; a porous aeration tube disposed at a lower part of the water storage chamber of the tank for aerating the waste gas introduced through the gas inlet conduit into the water to produce a multiplicity of bubbles; and solid matter separating means provided between the gas inlet conduit and the aeration tube for separating solid matters from the waste gas as the waste gas enters the aeration tube through the gas inlet conduit.

Brief Description of the Drawings The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: Fig. 1 is a cross sectional view of a waste gas purifier according to the present invention; Fig. 2 is a cross sectional view taken along line II-II in Fig. 1; and Fig. 3 is a partially enlarged cross sectional view showing the structure of an inlet conduit and a connection pipe in the waste gas purifier according to the present invention.

Best Mode for Carrying Out the Invention Referring to Figs. 1 and 2, an upright cylindrical tank 10, which constitutes the exterior of a waste gas purifier according to the present invention, includes a water storage chamber 12 for storing water W. The tank 10 is made of a material with excellent durability and chemical resistance, such as ceramic fiber. The tank 10 is provided at the external lower part thereof with a waste gas inlet port 14 for introducing waste gas, and the tank 10 is provided at the center of the top thereof with a purified air outlet port 16 for discharging purified clean air.

On the other hand, the tank 10 is provided at the external upper part

thereof with a water supplying port 18 for supplying the water W, and the tank 10 is provided at the bottom thereof with a water discharging port 20 for discharging the water W from the water storage chamber 12. Mounted at the water supplying port 18 and the water discharging port 20 are valves 18a and 20a for controlling the flow of the water W, respectively. The tank 10 is installed over the ground while being spaced apart from the ground by means of a plurality of legs 22.

As shown in Fig. 1, to the inner wall of the tank 10 is mounted a water level sensor 24 for sensing the water level of the water W. The water level of the water W sensed by the water level sensor 24 is set to an approximately intermediate position of the tank 10 so that the waste gas inlet port 14 is sufficiently submerged under the water W. The water level sensor 24 is adapted to detect the water level of the water W, and then transmit a water level sensing signal to a lamp 26 mounted to the outer wall of the tank 10.

The lamp 26 is turned upon receipt of the water level sensing signal transmitted from the water level sensor 24. Consequently, an operator can easily recognize the water level of the water W as the lamp 26 is lit. When the lamp 26 is lit, the valve 18a is closed so that the water W is not supplied any more.

Referring to Figs. 1 and 2, the outer wall of the tank 10 is covered with a thermal insulation material so that the water W is not frozen. Under the tank 10 is mounted a heater 30 for heating the water W. The heater 30 has a heating wire 32 for uniformly heating the water W, which is arranged throughout the outer bottom surface of the tank 10.

The waste gas purifier according to the present invention further comprises a waste gas inlet conduit 40 connected to the waste gas inlet port 14 for introducing the waste gas into the water storage chamber 12 of the tank 10, and an air blower 42 mounted in the waste gas inlet conduit 40 for blowing the waste gas to the water storage chamber 12 of the tank 10. The waste gas inlet conduit 40 is connected to waste treatment facilities, such as a waste incinerator or a food drier, for introducing waste gas produced when the waste is treated into the tank 10. The waste gas inlet conduit 40 has a vertical conduit part 42a in which the water W is filled. The water level of the water W in the waste gas inlet conduit 40 is equal to that in the water storage chamber 12 of the tank 10. Solid matters S in the waste gas, such as powder and dust, are deposited by means of the water W filled in the vertical

conduit part 42a of the waste gas inlet conduit 40.

Referring to Figs. 1 to 3, at the lower part of the water storage chamber 12 of the tank 10 is disposed a porous aeration tube 50 for aerating the waste gas introduced through the waste gas inlet conduit 40 into the water W to produce a multiplicity of small bubbles. The both ends of the aeration tube 50 are fixed to the bottom of the tank 10 by means of mounting brackets 56, respectively. The aeration tube 50 is formed in the shape of a hollow square pipe, which has an inlet formed at one end thereof. At the wall of the aeration tube 50 are formed a plurality of holes, through which the waste gas is emitted. In this embodiment, the aeration tube 50 is preferably made of a material with excellent durability and chemical resistance, such as ceramic, and the holes 54 of the aeration tube 50 are preferably formed with smallest possible diameters so that the holes 54 block the solid matters S and produce small bubbles. It is also possible to form the aeration tube 50 in the shape of a circular or polygonal section instead of the aforesaid square section. In this embodiment, a single aeration tube 50 is disposed at the lower part of the tank 10, though the number of the aeration tubes 50 may be increased depending upon the capacity of the tank 10.

Referring again to Figs. 1 to 3, the waste gas purifier according to the present invention further comprises solid matter separating means interposed between the waste gas inlet conduit 40 and the aeration tube 50 for separating the solid matters S from the waste gas as the waste gas enters the aeration tube through the waste gas inlet conduit. The solid matter separating means comprises a connection pipe 60, which is extended from the end of the waste gas inlet conduit 40 and connected between the end of the waste gas inlet conduit 40 and an entrance 52 of the aeration tube 50. At the lower part of the connection pipe 60 is formed a solid matter separating passage 62 for discharging the solid matters S. As best shown in Fig. 3, at the inner wall of the connection pipe at the vicinity of the solid matter separating passage 62 which is closest to the aeration tube 50 is formed a protrusion 64 for retarding the flow of the solid matters S proceeding to the aeration tube 50 to facilitate discharging of the solid matters S through the solid matter separating passage 62. In this embodiment, the waste gas inlet conduit 40 and the connection pipe 60 are individually formed and they are connected to each other as shown in Figs. 1 and 3, though the connection pipe 60 may be integrally formed with the end of the waste gas inlet conduit 40.

The solid matter separating means further comprises a chute 66 for guiding the solid matters S discharged through the solid matter separating passage 62 of the connection pipe 60 so that the solid matters S are collected at the lower edge of the tank 10, and a collection chamber 68 formed at the lower edge of the tank 10 for collecting the solid matters S guided by the chute 66.

Referring again to Figs. 1 and 2, in the tank 10 is disposed a screen 70 for partitioning the water W into upper and lower layers. The screen 70 has a plurality of small holes 72, through which the upper layer of the water W communicates with the lower layer of the water W. The lower layer of the water W partitioned by the screen 70 is the region where bubbles B are produced by the aeration tube 50. On the other hand, the upper layer of the water W is the region where toxic components in the bubbles are removed.

The edge of the screen 70 is securely attached to the inner wall of the tank 10 so that the bubbles B produced in the lower layer of the water W only pass through the holes 72 of the screen 70.

On the screen 70 is placed adsorption means for adsorbing the toxic components in the bubbles, for example, an elvan bed 80, which is submerged under the water W. Elvan constituting the elvan bed 80 is a porous rock with large specific surface area. The elvan is very effective for adsorbing and removing toxic components, such as dioxin, volatile organic compounds, heavy metals, etc. The elvan performs strong antibacterial and deodorizing functions. Furthermore, the elvan activates the water W by means of the emission of far infrared rays to improve the quality of water and convert acid and strong alkali water into weak alkali water. In this embodiment, the elvan bed 80 is used as the adsorption means, though a porous zeolite bed, an activated carbon bed, or a ceramic carrier bed may be also used.

The waste gas purifier according to the present invention further comprises solid matter discharging means for conveying the sludge-phase solid matters S deposited in the collection chamber 68 out of the tank 10 to discharge the solid matters S, for example, a screw conveyor 90. As shown in Fig. 2, the screw conveyor 90 comprises: a cylinder 92 having an inlet 92a communicating with the collection chamber 68 and a downwardly slanted outlet 92b extended from the circumference of the cylinder 92 in such a manner that it is formed at a position higher than a horizontal level W2, which is equal to a water level Wl of the water W; a screw 94 rotatably disposed in

the cylinder for transferring the solid matters S; and a motor 96 for rotating the screw 94. The cylinder 92 is attached to the outer wall of the tank 10 by means of a joint bracket 92c. The screw 94 has a shaft 94a, on which a spiral blade 94b is longitudinally formed. The shaft 94a is supported by means of a bearing 8. In this embodiment, the screw conveyor 90 is used for conveying the solid matters S, though a conventional bucket elevator may be also used.

The operation of the waste gas purifier with the above-stated construction according to the present invention will now be described in detail.

Referring to Figs. 1 and 3, the waste gas blown by the air blower 42 makes contact with the water W filled in the vertical conduit part 40a of the waste gas inlet conduit 40. The solid matters S in the waste gas, which passes through the water W in the waste gas inlet conduit 40, are deposited by means of the water W. The waste gas having passed through the waste gas inlet conduit 40 is supplied to the aeration tube 50 via the connection pipe 60.

The waste gas passes through holes 54 of the aeration tube 50 to produce a multiplicity of small bubbles B. Water-soluble toxic components contained in the bubbles B are dissolved in the water W.

Subsequently, the bubbles B pass through the holes 72 of the screen 70 to make contact with the elvan bed 80. The bubbles B are sheared to produce more minute bubbles as they pass through small air holes of the elvan bed 80. The toxic and malodorous components in the waste gas are adsorbed by means of the elvan bed 80 so that the components are removed from the waste gas. The resulting clean air, which has been risen to the water level Wl of the water W, is discharged to the atmosphere through the air outlet port 16 of the tank 10.

As shown in Figs. 2 and 3, the solid matters S deposited in the vertical conduit part 42a of the waste gas inlet conduit 40 are introduced into the connection pipe 60 via the waste gas inlet conduit 40. The solid matters S having been introduced into the connection pipe 60 is discharged out of the connection pipe 60 through the separating passage 62, guided along the chute 66, and collected in the collection chamber 68. The protrusion 64 of the connection pipe 60 serves to retard the flow of the solid matters S so that discharging of the solid matters S through the separating passage 62 is facilitated. Consequently, the solid matters S are perfectly removed before they approach the entrance 52 of the aeration tube 50, by

which blocking of the holes 54 of the aeration tube 50 due to the solid matters S is prevented, and thus contamination of the water W and reduction of the adsorption efficiency of the elvan bed 80 are effectively prevented. The result is that the service life of the waste gas purifier according to the present invention is extended, the operational reliability of the waste gas purifier is improved, and the economical operation of the waste gas purifier is possible.

Referring to Figs. 1 and 2, as the screw 94 is rotated by means of the motor 96 of the screw conveyor 90, the blade 94b of the screw 94 rotated in the cylinder 92 transfers the sludge-phase solid maters S collected in the collection chamber 68 along the cylinder 92. The solid matters S transferred along the cylinder 92 by rotation of the screw 94 are discharged through the outlet 92b of the cylinder 92.

Industrial Applicability As apparent from the above description, the present invention provides a waste gas purifier having a simple structure and capable of conveniently and efficiently eliminating toxic and malodorous components from waste gas generated when various kinds of waste are treated.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.