US3812796A - Refuse incinerator - Google Patents

Abstract

A refuse incinerator adapted for burning plastic refuse in a sanitary and efficient manner, which comprises a primary combustion chamber and a secondary combustion chamber, the latter being slanted in relation to the former, such that the secondary combustion chamber functions not only as a furnace chamber but also as a passageway for refuse moving into the primary combustion chamber, thus, the refuse is completely burned thereby avoiding air pollution.

Description

United States Patent [1 1 Nagata et al.

[ May 28, 1974 REFUSE INCINERATOR inventors: Tadayoshi Nagata; Wahei Hamanaka, both of Osaka, Japan Assignee: lwatani 8L Co., Ltd., Osaka, Japan Filed: Mar. 22, 1973 Appl. No.: 343,735

[1.8. CI. 110/10, 110/15, 110/18 R Int. Cl F221) 33/18 Field of Search 110/8 R, 8C, 10, 15, 18 R,

References Cited UNITED STATES PATENTS 6/1907 Wiegmann et a1 110/15 8/1931 Graver 110/15 3,448,702 6/1969 McLouth llO/l8 3,534,693 10/1970 Sugano llO/lO 3,643,633 2/1972 Sugano llO/lO Primary Examiner-Kenneth W. Sprague Attorney, Agent, or Firm-Bacon & Thomas [5 7] ABSTRACT A refuse incinerator adapted for burning plastic refuse in a sanitary and efficient manner, which comprises a primary combustion chamber and a secondary combustion chamber, the latter being slanted in relation to the former, such that the secondary combustion chamber functions not only as a furnace chamber but also as a passageway for refuse moving into the primary combustion chamber, thus, the refuse is completely burned thereby avoiding air pollution.

6 Claims, 8 Drawing Figures PATENTEDIAY m4 I $812,796

SHE 1 UF 3 ill? PATENTEUHAYZB m4 SHEU 2 [IF 3 1 REFUSE INCINERATOR BACKGROUND AND OBJECTS More specifically, the invention is concerned with improvements in an incinerator especially adapted for burning heat fusible wastes, such as plastic refuse, wherein the furnace chamber is divided into a primary combustion chamber and a secondary combustion chamber, the latter being upwardly inclined in relation to the former and being in communication with a flue. In addition, the secondary chamber is adapted to receive the refuse to be treated on the slanted inside wall thereof.

In recent years, world wide attention is being focused on environmental pollution problems, and many proposals for their solution have been made and put into practice. However, as is well known, plastic refuse provides an especially serious problem in its combustion, since there tends to be incomplete combustion due to its sticky property at elevated temperature. This results in secondary air contamination. In order to accomplish the burning in a sanitary and effective manner, it is essential to develop a specialized incinerator for disposing of plastic refuse.

In view of these facts, an object of this invention is the complete combustion of plastic refuse by providing a primary combustion chamber and a secondary combustion chamber serving to receive and pre-heat the refuse, the secondary chamber being in communication with a flue, and the primary chamber including a residue discharging gate, thereby enabling the refuse to burn effectively in both combustion chambers.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more particularly described by way of example with reference to the accompanying drawings, wherein:

FIG. I is a cross-sectional front view of a refuse incinerator according to the present invention,

FIG. 2 is a sectional view taken along the line ll in FIG. 1,

FIG. 3 is a sectional view in enlarged scale showing the connection of air jet pipes to the wall of a combustion chamber according to a modification of the present invention,

FIG. 4 is a schematic view showing an example of another modiflcation of the present invention,

FIG. 5 is a sectional view showing an example of air jet pipes other than those illustrated in FIG. 1,

FIG. 6 is a sectional view of a further example of the air jet pipes,

FIG. 7 is a cross-sectional front view of a modification of the present invention,

FIG. 8 is a sectional view taken along the line VII- VII in FIG. 7.

DETAILED DESCRIPTION OF THE DRAWINGS In the following description and drawings, like reference characters indicate like parts.

FIGS. 1 and 2 Referring to FIGS. 1 and 2, a primary combustion chamber 1 is connected to a secondary combustion chamber 2 slanted upwardly therefrom, which chambers are unified into a single furnace chamber. The primary chamber 1 includes a residue discharge gate 3 at the rear end thereof, and the secondary chamber 2 has a refuse charge gate 4 at which a flue 5 is vertically extended in relation to the primary chamber. Both chambers are surrounded by spaced air jet pipes 6 welded thereto, each pipe having a plurality of air supplying openings or nozzles 7, which are in communication with either of a pair of air distribution ducts 8 effectively connected to a blower 9. The ducts are buried in fire-proof bricks underlying both chambers. The primary combustion chamber 1 can also be slanted,-but at a smaller angle than the slant of the secondary combustion chamber 2.

The combustion chambers 1 and 2, the residue discharge gate 3, the flue 5, and the refuse charge gate 4 are water-tight and connected to one another. and are safely submerged in water in a tank 10 built in the space adjacent both combustion chambers and the flue. The tank 10 stores water, and equally serves as a cooling jacket. Accordingly, both combustion chambers I and 2, the flue 5, the residue discharge gate 3, the refuse charge gate 4, and their parts are effectively cooled by the affluent water in the tank, which is provided with a vapor exhaust tower I] in the top thereof, wherein vapor escapes from an opening 12.

For a cooling jacket, other versions can be made; for example, in the simplest form, a cylindrical jacket may be provided on the circumference of the combustion chambers, the flue, and the residue discharge gate, water being circulated in the jacket. Under this system, however, when a very large increased quantity of refuse is burned with such increased heat, the water is quickly vaporized, thereby resulting in the necessity of continual water supply. Hence, an extra water tank must be prepared to make up for the loss of water in a rapid and efficient manner, thus requiring a specially-designed piping arrangement. As a matter of course, this leads specially designed mechanical complication and increased cost. In contrast, the example illustrated in FIG. 1 utilizes the relatively large space above the combustion chambers and beside the flue, which would otherwise remain a useless and empty space, so as to pro vide a water tank functioning as both a water supply tank and a cooling jacket for the combustion chambers and the surroundings. Advantageously, this eliminates the necessity of installing the extra tank and pipingfor circulating the cooling water.

FIGS. 3 and 4 In the exampleillustrated in FIG. 1, the air distribution ducts are buried in the fire-proof bricks underlying the combustion chambers. But the location of the ducts is not so limited, and it can be located in situ in the equipment as long as they are protected against detrimental overheating. In the example illustrated in FIG. 4 the air distribution ducts are extended inside the water tank, and are completely submerged in the water.

Alternatively, the ducts may be held in contact with the water in the tank; preferably, in an area larger than the semi-circle, wherein the cooling means can be either in the form of the tank system or the cylindrical system.

As described above, the primary combustion chamber 1 and the secondary combustion chamber 2 are surrounded by the spaced air jet pipes 6; however, the pipes have a tendency to disintegrate or decompose at elevated temperatures. Therefore, in the example illustrated in FIG. 3 this problem is solved by enabling the larger outer surface of each pipe to face the cooling side or water side; whereas, the smaller outer surfaces thereof are faced toward the combustion chamber. Thus, the cooling area is larger than the heating area, thereby ensuring the efficient cooling of the air jet pipes 6.

FIGS. 5 and 6 In the examples enumerated above, the openings of air jet pipes 6 open in the same plane with the inside wall surfaces of the combustion chambers. It is possible, however, for the openings to be choked by soot deposit or any other residual substances produced during the course of burning the refuse, thereby obstructing air from being adequately jetted into the combustion chambers. This is primarily due to the fact that the surrounding area of each opening isrendered at a lower temperature by passing air therethrough in comparison with the walls of the combustion chambers, thereby enabling soot or any other substance to gather in a condensed form. In the example illustrated in FIGS. 5 and 6, this problem is solved by extending the air jet ends like nozzles inside the combustion chambers, thus maintaining the openings of air jet pipes at such high temperatures that soot and other obstructive sub stances are prevented from being deposited. Specifically, as shown in FIG. 5, nozzle-shaped air jet projections 27 are provided in which passage of air is individually permitted.

ered with a mantle having an appropriate space therebetween, such that the space provides an air passageway. The walls of the combustion chambers periodically include a plurality of apertures open to the inside of the combustion chambers. In such cases, in view of soot deposit problems the open end of each aperture can be in the form of a nozzle mentioned above, as shown in FIG. 6, wherein reference character 13 indicates the mantle.

FIGS. 7-and 8,

Other various changes and modifications can be made without departing from the spirit of the present invention. For instance, in the example illustrated in FIGS. 7 and 8, the refuse charge gate is located in the primary combustion chamber, instead of being located at the base of the flue as illustrated in FIG. 1. This has been taken into consideration since when the refuse charge gate is provided in the secondary combustion chamber side, it is possible for the refuse to be prematurely ignited by flames rising from the primary combustion chamber, whereby the gas thus produced is likely to cause a backfire into the flue. Furthermore, if the secondary chamber is clogged with freshly charged refuse in succession through the gate, the burning efficiency is considerably reduced.

Normally, the temperature of flames is at a maximum in the area between the secondary chamber and the is vertically provided at the terminating end of the secondary chamber 32. The primary chamber 31 and the secondary chamber 32 are surrounded by a number of spaced air jet pipes 36 like the ribs surrounding a man s heart, each pipe being inwardly curved along the outline of the combustion chambers. The air jet pipes 36 have air supplying apertures 37 open inside the combustion chambers, and are in communication with air distribution ducts 38, which are supplied with air by means of a blower 39. A refuse charge tower 34 is provided in the top wall of the primary combustion chamber 31, the tower being forwardly inclined with support of a deck 44, on which the refuse is carried by a hopper (not shown) or any other suitable means. The refuse charge tower 34 has two gates 45 and 46; the first gate 45 being provided at the terminating end thereof and the second gate 46 being provided at a location inside the tower. Between the gates is formed a refuse storage area 47. The first gate 45 is opened and closed by an electrically driven chain 48; whereas, the second gate 46 is opened and closed by an air cylinder 49.

The features of the examples specified above can be appropriately combined within the spirit of the present invention.

OPERATION A refuse incinerator according to the present invention is operated as follows:

FIGS. 1 and 2 Referring to FIG. 1, a given amount of refuse is put into the secondary combustion chamber 2 through the gate 4, and the refuse is initially piled on the sloped inside wall thereof as indicated by the dotted lines. Subsequently, the residue discharge gate 3 is opened to ignite the refuse by a suitable burner (not shown), and simultaneously, air is blown through the air jet openings 7 by the blower 9, thus enabling the air to prevail throughout the combustion chambers. When the refuse is thus burned, it begins to melt into a fluid state, thereby moving downward along the sloped inside wall of the secondary combustion chamber, and reaches the primary combustion chamber, where it is finally burned to ash. When the refuse starts to burn by itself without the aid of a burner or other igniting means, the burner is removed out of the residue discharge gate 3. Flames are turbulent on the refuse, and rise up the secondary chamber while burning the subsequent pile of refuse remaining therein. In this way, the refuse is successively burned, and melted away into the primary chamber, pushing the initial pile of refuse almost transformed into ash toward the residue discharge gate from which the ash is readily taken away. As the refuse decreases in volume, the secondary combustion chamber is supplied with new refuse of a given quantity. The burning of refuse is thus continued. I

In this case, the walls of the combustion chambers are heated to high temperatures, but as is evident from the foregoing, they are safely cooled by the flowing water in the tank 10 occupying a relatively large area defined by the outer walls of the combustion chambers, and the outer side wall of the flue 5. The water is gradually vaporized into the atmosphere through the vapor exhaust tower l 1, thereby tending to diminish its quantity. But the water tank 10 contains such plenty of water that the vaporization of water cannot affect the cooling performance. In addition, the combustion chambers are completely submerged in the water in the tank, which will enhance the cooling efficiency. This will be particularly advantageous when the incinerator is operated for a long period of time, which would otherwise lead to overheating problems due to water shortage.

FIGS. 7 and 8 The example illustrated in FIGS. 7 and 8 is operated as follows:

The refuse is initially piled on the deck 44 and then is carried into the refuse storage area 47 through the I first gate 45. As the second gate 46 is opened, the refuse will enter the primary combustion chamber directly. Then, both gates are closed, and the refuse in the primary chamber is ignited by a pilot fire, followed by the actuation of the blower 39. The air is thus enabled to prevail throughout both combustion chambers, thereby flaring up the refuse. Some portion of the flames rise up the secondary combustion chamber 32, in the course of which the flames transform into gas, which is quickly sucked into the flue. Consequently, air is smoothly circulated from the primary chamber to the flue via the secondary chamber, thereby enabling the refuse to be burned efficiently.

When a new charge of refuse is supplied, the gates 45 and 46 are alternatively opened, so as to avoid the intrusion of outside air into the furnace. As described above, the charging refuse is initially piled on the floor of the primary combustion chamber, but it cannot make a pile on the sloped wall of the secondary combustion chamber, whereby the secondary chamber is protected against suffocation due to a pile of refuse. Hence, gaseous products are smoothly passed through. The gas produced is completely burned, thereby avoiding a possible backfire into the flue.

According to the present invention, the refuse is rendered combustibly molten at an initial stage, and when it is regularly burned, the refuse readily spreads its burning area fully throughout the floor of the primary combustion chamber. In addition, the active flames thus produced rise up the secondary combustion chamber, and burn the subsequent supply of refuse therein, which, as mentioned above, is rendered combustibly molten. In this way, the process is repeated. The ash is pushed by a newly born ash, and taken away from the discharge gate. Unlike prior art incinerators, the heaped ash does not hamper the burning.

As is seen in FIGS. 1 and 7, the furnace chambers are substantially surrounded by the water in the tank built by taking advantage of the space above the combustion chambers and beside the flue, wherein the tank equally functions as a cooling jacket, thereby ensuring a smooth circulation of cooling water under the convection action effected by the combustion in the furnace chambers. Accordingly, both combustion chambers, the flue and their surroundings are safely protected against overheating. The cooling water is compensated for losses due to vaporization, thereby enabling the incinerator to be operated for a relatively long period of time without the risk of water shortage. In addition, it is not necessary to install extra tanks and piping for cooling purposes, thereby resulting in economy and simplicity of construction.

In the example illustrated in FIG. 3, the air jet pipes are projected against damage and disintegration due to overheating by virtue of the relatively large surrounding cooling areas which are kept in contact with the water in tank. On the other hand, the smaller areas welded to the outer wall surfaces of the combustion chambers have the advantage of reinforcing the walls which are susceptible to cracks and breaks due to internal or external shocks, thereby securing a prolonged life for the incineratonAs a matter of course, the air jet pipes are kept safe from heat involved in internal combustion, thereby avoiding possible deformation and fatigue due to thermal expansion and contraction. Accordingly, the pipes can withstand long-term usage with constant efficiency.

In the example illustrated in FIGS. 5 and 6, the air supplying openings are kept free from soot and other obstructive substances, thereby enabling air to smoothly pass through.

In the example illustrated in FIGS. 7 and 8, the secondary combustion chamber is arranged so as to suck a burning gas smoothly and quickly into the flue, thereby contributing to the increased burning capability. Also, since the refuse charge gate is situated in the primary combustion chamber, thus providing for adequate control of the amount of charging material by the regulation of the gates, the secondary combustion chamber is kept safe from suffocation by the heaped refuse. Hence, possible backflres in the flue are prevented, and the refuse charge gate is not liable to dangerous heat radiation, which will be safely sucked into the secondary combustion chamber.

While several embodiments of the invention have been described, it will be understood that is is capable of many further modifications and this application is intended to cover any variations, uses, or adaptions of the invention following in general, the principles of the invention and including such departures from the present disclosure as come within knowledge or customary practice in the art to which the invention pertains, and

as may be applied to the essential features hereinbefore set forth and fall within the scope of the invention or the limits of the appended claims.

What is claimed is:

l. A refuse incinerator comprising:

means defining an elongated generally horizontal pri mary combustion chamber;

means defining an elongated inclined secondary combustion chamber sloping upwardly from one end of said primary chamber at such an angle as to retain solid refuse therein and communicating with said primary chamber;

a residue discharge gate at the other end of said primary chamber;

an upstanding flue extending from the upper end of said secondary chamber; v

a charging inlet means communicating with said secondary chamber adjacent the upper end thereof but below said flue;

a plurality of air conduits adjacent the outside of said primary and secondary chambers and having a multiplicity of nozzles directed therefrom into said chambers; and

means for directing and forcing air through said conduits into said chambers.

2. An incinerator as defined in claim 1 including means defining a coolant jacket substantially encompassing said chambers and conduits for holding a coolant liquid therein in heat conductive relation to said chambers and conduits.

3. An incinerator as defined in claim 1 wherein said 5. An incinerator as defined in claim 1 wherein said chambers are provided with substantially impervious nozzles project inwardly of said chambers to extend inbottom walls of heat resistance material. wardly of the inner surfaces thereof.

4. An incinerator as defined in claim 3 wherein said 6. An incinerator as defined in claim 2 wherein said means for directing and forcing air includes at least one 5 jacket comprises a water tank having vapor exhaust duct within said heat resistant material and communimeans at the top thereof. eating with said conduits.

Claims (6)

1. A refuse incinerator comprising: means defining an elongated generally horizontal primary combustion chamber; means defining an elongated inclined secondary combustion chamber sloping upwardly from one end of said primary chamber at such an angle as to retain solid refuse therein and communicating with said primary chamber; a residue discharge gate at the other end of said primary chamber; an upstanding flue extending from the upper end of said secondary chamber; a charging inlet means communicating with said secondary chamber adjacent the upper end thereof but below said flue; a plurality of air conduits adjacent the outside of said primary and secondary chambers and having a multiplicity of nozzles directed therefrom into said chambers; and means for directing and forcing air through said conduits into said chambers.

2. An incinerator as defined in claim 1 including means defining a coolant jacket substantially encompassing said chambers and conduits for holding a coolant liquid therein in heat conductive relation to said chambers and conduits.

3. An incinerator as defined in claim 1 wherein said chambers are provided with substantially impervious bottom walls of heat resistance material.

4. An incinerator as defined in claim 3 wherein said means for directing and forcing air includes at least one duct within said heat resistant material and communicating with said conduits.

5. An incinerator as defined in claim 1 wherein said nozzles project inwardly of said chambers to extend inwardly of the inner surfaces thereof.

6. An incinerator as defined in claim 2 wherein said jacket comprises a water tank having vapor exhaust means at the top thereof.

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