Technical Field
This invention pertains to an incinerator to dispose of solid waste originating especially from independent houses and residential flats in urban and semi urban areas where there is no organized way of collection and disposal of the solid waste in a scientific and hygienic manner on day to day basis. Incineration is a waste treatment process that involves the combustion of organic and inorganic substances contained in waste materials. Incineration of waste materials converts the waste into ash  flue gas and heat. The ash is mostly formed by the inorganic constituents of the waste  and may take the form of solid lumps or particulates likely to be carried by the flue gas. The flue gases can be cleaned of gaseous and particulate pollutants before they are dispersed into the atmosphere  by water scrubbing or passing through water irrigated packed tower or bubbling through water or by passing through suitable filters. In some cases  the heat generated by incineration can be used economically to even to generate electric power.
Background of the invention
As the life styles of the people are changing  so is the accumulation of domestic waste in rural and urban areas of India. Waste generated from households is generally accumulated in small containers (often plastic buckets) until such time  ether the community collection boys of the colony or the local administration agency  if any  comes for collection. Unfortunately such systems are not prevalent in most of the rural areas and even in many of the small cities in India. The net result is where ever we go  we can see the strewn stinking garbage especially on the road side or in some of the vacant plots available in the area.
In the community storage system practiced in some parts of India  individuals deposit their waste in bins located at street corners at specific intervals. The containers generally are constructed of metal  concrete  or a combination of the two. Community storage may reduce the cost of waste collection  and can minimize problems associated with lack of onsite storage space. However  unless these community storage arrangements are conveniently located  householders tend to throw their wastes into the roadside gutters for clearance by street sweepers. Even where storage arrangements are conveniently located  wastes tend to be strewn around the storage area  due to lack of time  indiscipline and result of scavenging of the wastes by rag-pickers and stray animals. Unless this is safely processed and disposed off  life can eventually come to a grinding halt. Contamination of food  water sources and surroundings would lead to serious health hazard. All our efforts towards our development would be thwarted by these thoughtless and injudicious acts of ours.
Several thousands of urban dwellers in India make their living upon wastes originated from many small industries using plastics  tin cans  bottles  bones  hair  leather  glass  metal etc recovered from municipal solid waste. All metals  unsoiled paper  plastics  glass  cardboard etc are readily marketable and hence recycled by householders themselves or Rag-pickers. By the time waste reaches the community bins  it contains very little in the way of recyclable and consists mainly of vegetable / fruit peelings  scraps of soiled paper and plastic  used toiletries etc. The larger proportion of organic matter indicates the desirability of biological processing of waste. Though Composting was a prevalent biological processing practice in India  due to non-availability of adequate space  efforts are being made to popularize waste segregation and utilization of the organic waste in biogas plant.
A recent survey conducted in Kerala has found the domestic waste which can be categorized as:
a) Organic waste (15%): Organic waste consists of food remnants  discarded vegetable pieces  meat and fish refuses and kitchen waste. These can be converted into earthworm compost or used for inputs for biogas plants.
b) Hazardous materials (5%): Hazardous waste comprises of discarded glass pieces and bottles. These can be collected and sold for alternate re use.
c) Recyclable waste (10%): Waste for recycling includes discarded plastic utensils  jars and metal waste as well as used books  magazines and newspapers
d) Solid waste (70%) : Solid waste (including electronic waste) comprise of rubber/leather shoes and slippers  bags  rexin  poly bags  clothes  sanitary napkins  remnants of catering service like paper plates  table spreads etc. Electronic and electric waste consist of damaged electric charger  gadgets  switches  wires  holders etc
The above problems are addressed by many inventors  mostly by suggesting industrial and large scale incineration plants which may not be viable for urban house hold purpose. However let us examine what those patents teach us.
Indian Patent application No. 280/CAL/2002 provides an incinerator with an ash control unit. According to this invention  incinerator comprises of a furnace with a supporting plate that defines a combustion chamber  there above and an ash receiving chamber there below in the furnace  the supporting plate being formed with a plurality of through-holes for passage of high temperature ash there through; and an ash control unit including a partitioning member that divides the ash receiving chamber into upper and lower ash chambers and that defines a vertically extending ash channel communicated with the upper and lower ash chambers  a rake that is disposed over the partitioning member within the upper ash chamber for stirring and permitting uniform distribution of the high temperature
ash on the partitioning member and for moving the high temperature ash into the ash channel  and a rotary member that is disposed to rotate provides an incinerator with an ash control unit.
Similarly 425/KOL/2006 discloses an incinerator comprising of: a furnace defining a combustion chamber and having a stack in fluid communication with the combustion chamber and having top and bottom open ends; and a flue gas-guiding mechanism including a flue gas conduit and a flue gas blower. The flue gas conduit has a generally L-shaped end portion extending into the stack and disposed between the top and bottom open ends of the stack. The flue gas blower is connected to the flue gas conduit for drawing flue gas out of the stack.
US 4768445 discloses a waste incinerator  especially for waste products from the chemical industry  comprising a horizontal  stationary or revolving  combustion chamber  and a vertical  brick lined afterburning chamber with circular cross section. The steel casing of the afterburning chamber is supported on an exterior furnace framework by means of a supporting ring on the chamber above the burner supported on a horizontal supporting frame. An upper steel casing segment of the afterburning chamber is separated from a lower steel casing segment above the entrance of the horizontal combustion chamber by a separating joint. The after burning chamber above the joint is suspended by a supporting ring engaged over a horizontal frame of the furnace framework. The joint is spanned by a compensator.
US 4815399 talks about an incinerator plant for waste materials having a large throughput capacity and/or partial-load operation comprises a combination of two rotary tube furnaces feeding into a common secondary combustion chamber provided with burners that can be selectively added in and turned off  and which in turn feeds gaseous products of combustion into a waste heat boiler having two boiler flues which are connected to a common steam drum. The plant requires only one monitoring system and  when provided with a rotary tube furnace and a furnace grate  can be used for the incineration of special refuse and household refuse simultaneously.
Another US Patent 5515793 discloses an incineration furnace for disposal of waste. A stirrer is rotated and driven through the inside of housing by a motor. Waste is agitated and mixed between movable tubes provided on the stirrer  and by first and second fixed blades deposed in the incinerator housing  thereby facilitating burning and incineration of the waste material.
None of these prior art patent can be adapted to the needs of common man living in urban areas in the countryside. That has led me to this simple but cost effective incinerator  within the reach of common man. Hence here we are addressing a suitable method to dispose off the 70% of the waste i.e. solid waste amongst others and come out with a simple solution i.e. low cost house hold incinerator. Hence we have devised an incinerator which can burn solid waste in a controlled manner without causing any pollution without leaving much solid residue  except ash which can be used for prefab material and for road lying. As the temperature generated is very high  within minutes  the waste is burned off easily and effortlessly as against the common method of disposal of the house hold and garden waste by landfill and backyard burning.
Backyard burning of household and garden wastes generates 580 grams (20 oz) of dioxins annually. But emissions can be decreased by using the incinerator under this invention which is simple but efficient in its working  with much less investment. But for more efficient conversion of all the waste in to ash and carbon dioxide it is proposed to introduce auxiliary fuel in the combustion chamber preferably from the domestic portable bio gas plant and scrubbing the exhaust gas by subjecting the exhaust gas to a water sprayer in a scrubber before letting out in the air.
Summary of Invention
A cost-effective incinerator comprising of: a combustion chamber with open bottom and a dome in the shape of a truncated cone at the top to which an effluent outlet is connected; a stand for holding the combustion chamber  having slits or longitudinal opening to function as grate  as well as means for holding the waste material as well as inlet to provide air required for the combustion and to get the ash disposed off; means for providing auxiliary fuel selected from biogas and LPG required for combustion; means for cleansing the flue gas selected from water scrubber  water irrigated packed tower  bubbling through water or suitable filters; a flue gas conduit generally U-shaped in fluid communication with the combustion chamber and the means for cleansing the flue gas; wherein the combustion chamber is having provision for loading the solid waste  removing the unburned waste/ clinker and a rake. The biogas produced in a portable biogas plant is directed towards the middle of the combustion chamber through a fuel burner having on- off control. In an yet another embodiment under the invention the means for cleansing the flue gas is a packed tower irrigated with water having the flue gas inlet at the bottom and the exhaust gas out let at the top.
Brief description of the drawing
These and other features  aspects and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings. This invention is well illustrated in the drawings  throughout  which  like reference numerals  indicate corresponding parts in the figures.
Fig-1. An isometric view of a standalone incinerator 
Fig-2A and 2B. Two different view of the incinerator 
Fig- 2C. Stand with grate 
Fig-3. View of an incinerator with auxiliary fuel and flue gas treatment facility
Fig-4. An isometric view of a incinerator with auxiliary fuel and flue gas treatment facility wherein 
1. Chimney for flue gas out let  2.Dome  3.Loading door lock  4. Loading door  5.Handle  6.Combustion chamber  7.Cleaning door  8.Rake  9.Grate  10.Stand -1  11.Ash tray  12.Portable bio gas plant  13.Flue gas pipe  14.Water scrubber  15.Waterinlet  16.Water spray  17.Effluent out let  18.Exhaust  19. Stand-2.
For the simple incinerator at the focus of this invention  optimal emissions will have to be achieved without the use of sophisticated gas cleaning equipment  if costs are to be kept to a reasonable level. Given careful design  construction and operation  however  it should be possible to achieve acceptable levels of emissions.
A significant proportion of municipal waste has value as fuel  but the waste composition in developing countries is such that it is often very difficult to achieve complete combustion using this alone. It is likely therefore that the incinerator will be designed to operate using auxiliary fuel and more complete combustion of waste. Potential pollutants can be contained within the resulting residue which  if disposed of carefully  reduces the risk of contamination of local groundwater. Consequently  whilst recycling has an important part to play  incineration frequently forms part of an overall strategy for the management of residential solid waste. There are however  a number of technical  social and environmental problems associated with incineration. These arise from the potential pollutants contained in the emissions and residual solids remaining after from the combustion process. But our state of the art design takes care of these aspects and achieves the complete destruction of the waste to a completely burned  sterile ash and the control of emissions by gas cleaning techniques to reduce particulates  acid gases and dioxins to the very low levels specified.
Detailed description of the invention
Here  we have tried to explain some of the preferred embodiments of the process under the invention with particular reference to the accompanying drawings. Properly controlled incineration is an effective means of reducing waste volume. It ensures cleaner and more complete combustion of waste and lends itself well to waste disposal in urban areas. Potential pollutants can be contained within the resulting residue which  if disposed of carefully  reduces the risk of contamination of local groundwater. Though a number of technical  social and environmental problems associated with incineration arise from the potential pollutants contained in the emissions and residual solids remaining after from the combustion process  we have this simple  affordable  but effective way of handling the domestic solid waste. This leads to a dramatic improvement in the quality of air emissions compared to the continuation of open burning dumps  and therefore offer a major environmental amelioration.
Referring to Fig.1  combustion chamber (6) can be preferably a cylindrical vessel fully opened at the bottom and welded with a dome (2) in the shape of a truncated cone having an opening at the top to which an exhaust pipe is connected. The said chamber is placed on a stand-1 (10) having slits or longitudinal opening to function as a grate (9) for holding the waste material while burning as well as to provide air required for the combustion. The said solid waste material of domestic origin is loaded in batches in the combustion chamber through the door (4) provided. The resultant ash will automatically get collected in the ash tray (11) provided below the grate over the stand. Provision also exists to rake (8) the burned solid residue. The combustion chamber has a door (7) for removing the materials like any unburnt material or clinker at the bottom portion of the combustion chamber.
In a preferred embodiment under the invention as shown in Fig-3 a cross sectional view and Fig-4  an isometric view of the incinerator with auxiliary fuel and flue gas treatment facility  depending on the type of solid waste to be disposed off  we can have add on like a portable biogas plant (12) to provide auxiliary fuel and water scrubber (14) placed over a stand-2 (19) for scrubbing the flue gas coming out of the exhaust of the combustion chamber. For diverting the exhaust flue gas  a inverted U shaped flue gas pipe (13) is connected between the combustion chamber and the water scrubber with provision of water inlet (15) and get it cooled and washed of any fly ash being carried by the flue gas by the water spray (16) before the exhaust gas is let out of the incinerator. The accumulated effluent water will over flow through the out let (17) provided and can be either discarded or can be gainfully utilized for irrigating the plants and other crops.
In the incinerator in its simple form  the solid waste is deposited through the waste inlet on the dome-shaped chamber into the combustion chamber. A lighted match stick is thrown into the chamber and the inlet is closed. The free air entering through the grilled bottom provides air required for the combustion aided by the chimney and creates a powerful draft. Intense burning results and decimates the waste in minutes. The incinerator of this type will be easy to operate and is an economical solution to the mounting solid waste problem in our country.
But the temperatures needed to break down dioxin are typically not reached when burning of plastics in the simple incinerator  causing high dioxin emissions. While plastic does usually burn  the dioxins remaining after combustion either float off into the atmosphere  or may remain in the ash where it can be leached down into groundwater when rain falls on the ash pile.
At the same time if dioxin is present in the flue gas in large quantity  we have to revamp the simple incinerator with an addition auxiliary fuel to burn the waste at high temperature to breakdown dioxin in the flue gas requiring exposure of the molecular ring to a sufficiently high temperature so as to trigger thermal breakdown of the strong molecular bonds holding it together. Some particles of fly ash may be somewhat thick  and too brief an exposure to high temperature may only degrade dioxin on the surface of the ash. For a large volume air chamber  too brief an exposure may also result in only some of the exhaust gases reaching the full breakdown temperature. For this reason there is also a time element to the temperature exposure to ensure heating completely through the thickness of the fly ash and the volume of waste gases.
There are trade-offs between increasing either the temperature or exposure time. Generally where the molecular breakdown temperature is higher  the exposure time for heating can be shorter  but excessively high temperatures can also cause wear and damage to other parts of the incineration equipment. Likewise the breakdown temperature can be lowered to some degree but then the exhaust gases would require a greater lingering period of perhaps several minutes  which would require large/long treatment chambers that take up a great deal of treatment plant space.
A side effect of breaking the strong molecular bonds of dioxin is the potential for breaking the bonds of nitrogen gas (N2) and oxygen gas (O2) in the supply air. As the exhaust flow cools  these highly reactive detached atoms spontaneously reform bonds into reactive oxides such as NOx in the flue gas  which can result in smog formation and acid rain  if they were released directly into the local environment. These reactive oxides are treated in the water scrubber before leaving to atmosphere.
Our incinerator designs include a high temperature zone  where the flue gas is ensured to sustain a temperature above 850 °C (1 560 °F) for at least 2 seconds before it is cooled down. They are equipped with auxiliary supply of fuel like biogas and LPG  preferably biogas to ensure this high-temperature burning. As for other complete combustion processes  nearly all of the carbon content in the waste is emitted as CO2 to the atmosphere.
The typical size of the incinerator is as under:

Sl. No Size Capacity
1 400 mm dia x 500 mm height x 6mm thick 3 cft.
2 500 mm dia x 625 mm height x 6mm thick 5 cft
3 600 mm dia x 750 mm height x 6mm thick 7 cft
4 700 mm dia x 845 mm height x 6mm thick 10 cft
5 900 mm dia x1000 mm height x 6mm thick 15 cft
6 1000 mm dia x1260 mm height x 6mm thick 20 cft

The combustion chamber of the incinerator as has the capacity of 3cft to 20cft with dia of 400mm to 1000mm with a height ranging from 500mm to 1300mm as can be seen above made of mild steel or stainless steel or aluminum sheet with thickness ranging from 4mm to 10mm preferably 6mm in the case of portable incinerator. The recommended gap between the grids of the incinerator grate provided in the stand is 6mm. In the case of incinerator of large capacity with permanent installation the combustion chamber can be lined with refractory bricks.
The advantages in comparison with the existing incinerator are:
a. Requirement of auxiliary fuel needed is minimal. No electricity is required.
b. Only a match stick is needed to ignite it.
c. It is portable and as such easy to relocate the incinerator:
d. Practically nil recurring expenses.
e. No smell as the burning is at high temperature.
f. It can be installed anywhere.
The novel features of the invention have been brought out by explaining some of the preferred embodiments under the invention  enabling the men in the art to understand and visualize the invention. It is also to be understood that the invention is not limited in its application to the details set forth in the above description or illustrated in the drawings. Although the invention has been described in considerable detail with particular reference to certain preferred embodiments thereof  variations and modifications can be effected within the spirit and scope of the invention as described herein above and with appended claim.

I claim:
1. A cost-effective incinerator comprising
a) a combustion chamber (6) with open bottom and a dome (2) in the shape of a truncated cone at the top to which an effluent outlet can be connected;
b) a stand-1 (10) for holding the combustion chamber  having slits or longitudinal opening to function as a grate (9) as means for holding the waste material as well as to provide air required for the combustion and to discard the ash;
c) means for providing auxiliary fuel  and the fuel is selected from biogas and LPG required for combustion;
d) means for cleansing the flue gas selected from water scrubber  water irrigated packed tower  bubbling through water or suitable filters;
e) a flue gas conduit (13) in fluid communication with the combustion chamber and the means for cleansing the flue gas 
and the said combustion chamber(6) is having provision of loading door(4) for loading the solid waste  removing the unburned waste/ clinker through the cleaning door (7) and a rake (8).
2. The incinerator as claimed in claim 1  wherein means for providing the auxiliary fuel in step (C)  preferably biogas produced in a portable biogas plant (12) through a fuel burner having on-off control and directing its flame towards the middle of the combustion chamber.
3. The incinerator as claimed in claim 1  wherein means for cleansing the flue gas in step(d) is a water scrubber (14) having the provision for spraying the water (15 & 16) at the top of the scrubber directing against the incoming flue gas from the combustion chamber via the flue gas conduit (13) at the top  an effluent over flow out let (17) at the bottom and an exhaust flue gas outlet (18) disposed off just above the effluent water outlet (17).
4. The incinerator comprising of a combustion chamber (6) with open bottom and a dome (2) in the shape of a truncated cone at the top to which an effluent outlet (1) can be connected; a stand-1 (10) for holding the combustion chamber  having slits or longitudinal opening to function as a grate (9) as means for holding the waste material as well as to provide air required for the combustion and to discard the ash.
5. The incinerator as claimed in claim 1  wherein the combustion chamber is made of mild steel with brick lining in case of incinerator of large capacity with permanent installation.
6. The incinerator as claimed in claim 1  wherein ash resulted from the combustion chamber is collected in the ash tray (11) provided below the grate on the stand-1 (10)
7. The incinerator as claimed in claim 1  wherein the combustion chamber can be in cylindrical or square or rectangular shape  preferably in cylindrical form.
8. The incinerator as claimed in claim 1  wherein the means for cleansing the flue gas is a packed tower irrigated with water  having the flue gas inlet at the bottom and the exhaust gas out let at the top.