Present invention provides drum roasting machine for raw nuts.

Particularly the present invention provides a compact drum roasting machine for cashewnuts
More particularly the present invention provides a mechanized machine for roasting cashewnuts with least involvement of human labour. Since the world demand for cashew kernels has been rising steadily for several years in the past conferring significant price increase, the processing of cashew remains still a highly profitable industry. Majority of the processing facility irrespective of mode of operation utilizes man power for various unit operations viz., moisture conditioning, roasting, shelling, kernel drying, peeling, grading and packaging. Roasting of raw cashewnut is the pre¬requisite for making it brittle and amenable for subsequent manual or mechanical cracking process to extract edible kernel. Existing drum roasting process is a manually operated one, requiring highly skilled personnel for feeding nuts, rotating the drum, controlling the fire beneath the drum and transfer roasted nuts and smear wood ash over it. Raw cashew nuts are fed manually into an inclined revolving drum which is heated initially to such an extent that the exuding oil ignites and burns, thus charring the shell. Roasting generally is done for 10 to 15 sec. decided by operator and the drum is rotated by hand during this period. The roasted nuts collected at the outlet, which are still burning, quenched off by sprinkling water and covered with ash to absorb the oil on the surface. Smoke emanating from drum roasting process is let in to air at height of 65' through brick constructed chimney. Conventional roasting methods available solely depend on manpower and are inefficient and imperfect They depend on skilled labour, consume a lot of space and are totally exposed to foreign particles, making it unhygienic. Mechanized roasting machine for raw cashew nut is an efficient roasting method, compact, reduces, manpower, fuel-efficient and eliminates skilled labour.

Reference may be made to a disclosure on Coffee-roasting machine (Tecaire S A-1984)
The machine consists of an assembly formed by an enclosing chamber and rotating drum, which is mounted in oscillating manner on a transverse shaft, so that the assembly can adopt two positions, are working or horizontal and the other discharge or tilted; a receiver hopper for the roasted beans; and an installation for extraction of fumes from the inside of drum. The disclosure may have limited application for roasting of coffee beans only. Central shaft provided obstructs transverse motion of coffee bean or like material (cashewnut) and this patent disclosure is restricted to coffee bean only which is physically different from raw cashew nuts. Reference may be made to a patent disclosure on Rotary stirring roasting (JP - 2005064859) Disclosed is a rotary stirring roasting machine with a single axis designed so as to facilitate work in taking-out time or charging time, prevent heated air from scattering, and cause no scorch on the surface due to heat-retaining and steaming effect. This machine has a uni-axial rotary stirring device of a polygonal rotary drum having a stirring device rotates the inside of the machine to prevent scorch; and the rotary drum is covered with a main body cover for double heat retention so that the stirring function at the inner surface of the drum makes heat penetrate into the inner parts of soybeans, herbs or the like without causing scorch on their surfaces to impart good flavor to ground soybeans or herbs and fill the drum with the hot air via heat retention without scattering so as to enable novel roasting. Rotary drum is hexagonal in cross section and stirring action, increasing retention time of material to be roasted and particularly developed for soybean having different surface structure and properties from that of raw cashew nuts. A disclosure (JP - 2000316007) on nut roaster .teaches a small size bean roaster that has a simple structure, can efficiently roast coffee beans, chest nuts, tea leaves and the like at a low temperature tastily without damage of their plant tissues and is suitable for home brewing, in small-size coffee shops, and test roasting.

The cover of an almost conical shape is fitted to the opening of the metal-made drum body of a cylinder-shaped vessel that has ceramic layers formed inside. The holder having the female threads at the top end and having the material-charging inlet bored on the shaft center is inserted from the opening formed on the upper part of the cover and thread-fastened with the handle having the male thread from the hole bored on the bottom of the drum main body whereby the roaster machine drum is assembled. The roaster machine drum is rotatably supported to the rotary bed so that the material-charging inlet may face toward upper side with the step difference between the groove formed on the outer periphery of the charging inlet and the root of the handle and the rotary bed is made place able on the table cassette gas ring. For example, coffee beans are charged in the drum and roasted with the table gas ring, as the drum is rotated with the handle. Manually operated using rotary handle and difficult to process bulk quantity continuously.
An European patent (EP - 00128605) on Roasting device and method for roasting green coffee or the like Discloses household coffee bean roasting machine has a rotating drum (4) incorporating a number of apertures (42) through which the roasting process can be observed. The drum is supported within a housing (2) and has a wall (38) formed at least partially of a grid (40) made of galvanised basket-woven wire. Rotary drum-type roasting machine (JP - 2000012576) disclosed in the patent teaches a new roasting machine to solve such a problem that, in conventional open-type rotary drum-type roasting machines, the finished quality of the final products have been unable to be delicately regulated because their ventilation and exhaust performances or the like have been unable to be regulated. This rotary drum-type roasting machine has such a scheme that, a drum body 12 provided with a number of ventilation ports 14a on the circumferential wall 14 and a number of stepped plates 13 inside is windingly mounted with a shutter 31 provided with a number of regulatory ports 33a, and by regulating the position of the shutter 31, each of the divergences of the ventilation ports 14a is regulated.

Furthermore, a circular arc-shaped to-be- treated object facing wall 51 standing against the residence range of a to-be- treated object i inside the drum body 12 and a suction air head 42 with a suction port 54 opened on the wall 51 are put into the drum body 12, and by subjecting the suction air head 42 to positional regulation in such a direction as to alter the distance between the wall 51 and the to-be-treated object I, both forced exhaust and heat residence are ensured to regulate; thereby both the taste and quality such as flavor of the final product can be regulated delicately. Reference may be made to a Chestnut roasting machine, capable of maintaining a clean state by discharging impurities during operation (KR -1020090101655) In this disclosure ,a chestnut roasting machine is provided to periodically discharge impurities since a door is installed on the lowest part of the inclined floor of a tank. A chestnut roasting machine comprises a main body(10), a roasting drum(30), an opening/closing unit(40) and a control unit(50). The heater of the main body is installed between an inner drum(11) and an outer drum(12). The roasting drum is rotatably held in the main body. A plurality of through-holes is formed over the whole surface of the roasting drum. The opening/closing unit is installed by the disposing of a cover(41) on one side of the roasting drum. The opening/closing unit opens/closes the roasting drum by the rotation of a spiral shaft (42). The control unit controls the temperature of the heater and the rotating time of the roasting drum as setting conditions. Heat assembly provided in the annular space, increasing the cost of the machine and lower heat utilization efficiency. A machine and method for treating edible material disclosed by Ryley et al , 2001) tells abut a machine and method for treating edible material inparticular for roasting or caramelising edible particulate material.

The machine (1) for roasting or caramelising edible particulate material includes: a drum assembly (3) having a drum (5) for receiving edible particulate material, drive means (9) for rotating the drum (5) about its longitudinal axis, heating means (15) for heating the drum (5) to heat the edible particulate material, and means (23) for mounting the drum assembly (3) for tilting movement about an axis generally transverse to the longitudinal axis (13) of the drum for movement of the drum between an operative position, in which rotation of the drum (5) induces tumbling of the edible particulate material as the drum (5) is heated by said heating means to promote caramefization or roasting of the edible particulate material, and a discharge position in which the drum assembly (3) is tilted so as discharge the contents of the drum (5). Suitable for roasting materials requiring high temperature for caramelization and where tilting of drum is required while in operation. Rotary drum-type roasting machine disclosed by YOKOYAMA SEISAKUSHO in a Japanese patent publication (. JP-2000012342) teaches roasting machine to solve such problems that, in a conventional rotary-type roasting machine, because the box space is fairly wide relative to the quantity of a to-be-treated object to be charged therein, the direct thermal efficiency of a burner for roasting such an object is very low; but diminishing the rotary drum diameter is impossible because of resulting in lower agitating action. This rotary drum-type roasting machine has such a scheme that, inside a rotary drum 11 with both ends opened and the circumferential wall 15 made of wire net, a hollow cylindrical medium drum 41 with both ends closed is mounted. Therefore, the substantial magnitude of the internal space 3a of the box 3 becomes smaller by the volume of the medium drum 41 and thereby the proportion of the heat from a burner 7 scattered into the internal space 3a is becomes smaller and the direct thermal efficiency for heating a to-be-treated object in the rotary drum 11 becomes very higher; nevertheless, since there is no need of reducing the diameter of the rotary drum 11, the diffusion effect of the to-be-treated object does not fall as well; deposits or the like adhered to the medium drum 41 are continually removed with a brush 52. Wire mesh provided inside over which material is conveyed, receives direct heat and not suitable for raw cashewnut s requiring conduction heat for better roasting process.

In yet another patent ( JP- 17942397)a roasting machine for chestnut has been disclosed This is a roasting machine for chestnuts capable of preventing baking unevenness from occurring, eliminating an artificial assistance during the baking and improving the usability. This roasting machine for chestnuts is capable of forcibly stirring the chestnuts charged into a drum 20 therein by rotating the drum 20 in a horizontally kept state of the drum shaft and uniformly heating the drum peripheral wall 21 with a heat source 30, thus evenly heating the whole chestnuts stirred in the drum 20 and preventing baking unevenness from occurring. For example, the heating time, etc., can initially be set before the roasting to thereby eliminate the need for temperature control during the roasting and artificial assistance and improve the usability. Vertical type machine and not continuous one, being batch type suitable for chestnut only, it cannot be used for raw cashewnuts. Reference may be made to a Grain roasting machine and method by Schnupp Dale L. US -1987 This grain roasting machine includes an elongated hollow roasting drum mounted for rotation about its fore-and-aft longitudinally-extending central axis and a burner for producing a roasting flame within the drum in a direction extending generally longitudinally of the drum from one end toward the other end of the drum. The flame is produced in the longitudinal direction but offset to one side of the central axis of the drum. Vanes disposed on the interior of the drum sidewali and extending longitudinally between the ends thereof carry grain placed in the drum along a first arcuate path which skirts the periphery of the flame and then drop the grain in a second linear path in which most of the grain falls across the drum and directly through the roasting flame before returning to the first path. The drum is constructed by welding or otherwise rigidly connecting a plurality of plates together at their longitudinal edges so as to form an endless ring-like structure which defines the continuous sidewali of the drum. Each of the plates has an integrally-formed flange, being connected to the plate along one of its longitudinal edges. The flanges extend generally radially inward toward the central longitudinal axis of the drum so as to define the grain carrying vanes. The disclosure does not teach about using a hollow cylinder to transfer the material continuously which is required for raw cashewnuts to expose to heat for certain period only.

In another disclosure a grain roasting machine is disclosed (Schnupp Dale L -1986) which includes an elongated hollow roasting drum mounted for rotation about its fore-and-aft longitudinally extending central axis and a burner for producing a roasting flame within the drum in a direction extending generally longitudinally of the drum from one end toward the other end of the drum. The flame is produced in the longitudinal direction but offset to one side of the central axis of the drum. Vanes disposed on the interior of the drum sidewall and extending longitudinally between the ends thereof carry grain placed in the drum along a first arcuate path which skirts the periphery of the flame and then drop the grain in a second linear path in which most of the grain falls across the drum and directly through the roasting flame before returning to the first path. The drum is constructed by welding or otherwise rigidly connecting a plurality of plates together at their longitudinal edges so as to form an endless ring-like structure which defines the continuous sidewall of the drum. Each of the plates has an integrally-formed flange, being connected to the plate along one of its longitudinal edges. The flanges extend generally radially inward toward the central longitudinal axis of the drum so as to define the grain carrying vanes. Old technique known of roasting machine explained under Grain roasting machine and method (Schnupp Dale L. US - 1987), and does not indicate use of any hollow cylinder to transfer the material continuously which is required for raw cashewnuts to expose to heat for certain period only) Reference is made to another disclosure (192633 - A23N12/10) wherein is disclosed a Roasting Drum, which is axle mounted on two bearings, carrying within it, ribs as well as filter arrangement. Hopers are provided at the inlet and outlet for feeding and exit of grains. The rotating drum is motor-driven through gears to meet the required torque and RPM. After roasting, the movable bearing mount at the open end of the drum is lowered vertically, so that the closed end of the drum attains a higher position than the open end and consequently the grains exit through a conical filter arrangement, separating from the intermediate material. The patent discloses an axle mounted drum , which obstructs flow of material) In yet another disclosure (198075 - A23N12/08) sandless roaster is aimed to provide an atomized, continuous type roaster, without using the intermediate mammal, which is normally sand, making tits process easier and hygienic. Further, this process also minimizes the dependency on man-power or skilled labour which is a scarcity these doss. This unit basically rotating drum, which otherwise may result in over-roasting of grains. Further, this is a direct method which yields crisper grains. Machine meant for making crisp and not for roasting.

A grain roasting and puffing machine and a grain roasting and puffing method using thereof is disclosed in a Korean published patent (KR-1020100008057) wherein are provided to puff grains in a floating state in a vacuum condition by passing hot air through the grains. A grain roasting and puffing machine comprises the following, a main body(110) including a grain inlet unit(120) for inserting grains into the main body; a funnel(121) connected to a roasting and puffing unit(130); a lid(122) for opening and closing the funnel; a hot air heater(160) and a hot air blower(140) roasting and puffing the grains using hot air in the vacuum condition; a skin removing unit(150) collecting skins from the grains and discharging the skins to the outside; a grain cooling and discharging unit(170) cooling and discharging the puffed grains; a roasting and puffing drum(131) being opened and closed by a grain discharging unit(171); a drum support member(132) for supporting the roasting and puffing drum; and a hot air supply pipe(134) detachably installed on the hot air heater. It is convective type roasting system which is not suitable for roasting raw cashewnuts wherein conditioning of nuts is essential to make it porous for kernel extraction process. It is an object of the present invention to provide a drum roasting machine for raw nuts which obviates the drawbacks of the prior art. Another object of the present invention is to provide a mechanized drum roasting machine utilizing minimum number of labour.
A still another object of the present invention is that LPG as the heating source for the pre conditioning of nuts. Another object of the invention is to provide an exhaust to comply with the strict pollution norms by employing scrubbers. In the drawing accompanying the specification, Fig 1 shows an embodiment of the drum roasting machine.

(1) Is an embodiment of drum roaster assembly, (2) is a heating gas pipe feeding gas to a burner assembly, (3) is a gas carrier tank, (4) is a drum frame structure for fixing the drum, (5) is a chimney pipe for exhaust gases,(6) is a nut conveyer, (7) is a feed hopper with nut arrester, (8) is a longitudinal gas burner receiving gas feed from pipe (2), ( 9) is a nut motion regulator.
Fig 2 shows an embodiment of the details of the nut regulator mechanism wherein (22) is the chimney for exhaust gases, (23) is the feed mechanism arrying nuts, (24) is the funnel feed to the drum roaster (26), (25) is a flip flop means for regulating entry of nuts to the drum roaster, (27) are a pair of metal rods fixed to the drum roaster on opposite ends. Accordingly the present invention provides a drum roasting machine for raw nuts which comprises a drum roasting means (1) fixed rigidly to a frame (4) fixed rigidly to the ground, the said drum roasting means capable of being rotated by a prime mover (10), the rotation of said drum roaster being accomplished by power reduction mechanism, the said drum roasting means having pair of metal rods (27) fixed rigidly on opposite sides, a heating gas pipe (2), receiving heating gas from a tank (3), a gas burner means (8) receiving gas from pipe (2), the said gas burner means being fixed to the said drum roasting means (1), a chimney (5) fixed to said drum roasting means (1), a nut conveyer means (6) comprising plurality of small buckets capable of holding raw cashew nuts , the said nut conveyer means further being capable of regulating its movement upward to transfer to funnel like structure through power reduction mechanism transporting nuts to a feed hopper (7), a nut regulator means (9) comprising a flip flop mechanism (25), the said flip flop mechanism capable of operation by falling nuts (28) to the said roasting drum (1) by means of a funnel (24) to convey only desired quantity to drum roaster to ensure optimum roasting process, the said drum roasting means capable of having controlled temperature in a range of 450 to 650°C during the nut roasting process.

In an embodiment of the present invention wherein drum roasting means may be made of mild steel, stainless steel. In an embodiment of the present invention wherein the prime move may be an electric motor of typically 0.37KW. In yet another embodiment of the present invention wherein the prime mover may be driven by solar energy. In a further embodiment of the present invention wherein the power reduction mechanism may be a reduction gear with a preferred ratio of 110:1 to 58:1 In another embodiment of the present invention wherein, heating gas may be liquefied petroleum gas. sync gas, producer gas. In a further embodiment of the present invention wherein the gas burner means may be a meander type structure with small outlets. Preliminary studies were conducted to identify factors influencing the quality of end product. It was identified that i) Physical condition of the raw cashewnut; ii) Feed rate, iii) Temperature of furnace [resident time of nuts being roasted while passing along the slope of drum] and iv) Rotational speed (RPM) of revolving drum are the deciding factor to extract white whole kernels with minimal damage after shelling. Described below is the best mode of operation of the drum roasting machine. Basically drum roasting machine consisted of a bucket elevator operated by 0.37 kW electrical motor, revolving drum, power transmission system, heating assembly and chimney or smoke outlet (Fig 1). Raw cashewnuts available in the feed hopper are conveyed to feeding chute through bucket elevator. Nuts are then transferred to inlet of the drum roaster having 7° slope to the horizontal axis. Revolving drum is 1.25 m length having 0.16 m cp made up of 4 mm thick mild steel. Nut regulator is provided i.e. a square rod of 0.01 m2 c/s having length of 1.00 m, inner side of the revolving drum to turn the nuts and ensure uniform roasting. Roasting drum derived rotational motion from 0.37 kW electrical motor) through power reduction (Gears and sprocket assembly). A longitudinal gas burner is provided beneath roasting drum throughout its length and the gas pipe is connected to liquefied petroleum gas (LPG) with control valve. In order to regulate the roasted nut at the outlet of the drum roaster, a curved SS plate is provided and the burning nuts falling out of the plate were quenched off by water spray. Chimney having 0.3 m sq and 7.2 m height is provided to develop sufficient suction force to aspirate smoke emanating from drum roasting of raw cashewnuts inside the revolving drum.

Preliminary trials with roasting drum indicated that a minimum of 320°C (drum temperature) is required for raw cashewnuts to initiate roasting process, ignition started through LPG burner and roasting drum is allowed to revolve at specified rotation per minute (rpm) without loading raw material. When the temperature of the revolving drum attained 320 to 330°C, raw cashewnuts were transferred to roasting drum from feed hopper through bucket elevator. Feed rate of the raw cashewnut is set to specified quantity depending on the size and initial moisture content and controlled through motor and pulley assembly.

Main advantages of the present invention are.

1. There is minimal use of human resource.

2. The nuts are roasted uniformly without any burnt pieces

We claim:

1. A drum roasting machine for raw nuts which comprises a drum roasting means (1) fixed rigidly to a frame (4) fixed rigidly to the ground, the said drum roasting means capable of being rotated by a prime mover (10), the rotation of said drum roaster being accomplished by power reduction mechanism, the said drum roasting means having pair of metal rods (27) fixed rigidly on opposite sides, a heating gas pipe (2), receiving heating gas from a tank (3), a gas burner means (8) receiving gas from pipe (2), the said gas burner means being fixed to the said drum roasting means (1), a chimney (5) fixed to said drum roasting means (1), a nut conveyer means (6) comprising plurality of small buckets capable of holding raw cashew nuts , the said nut conveyer means further being capable of regulating its movement upward to transfer to funnel like structure through power reduction mechanism transporting nuts to a feed hopper (7) , a nut regulator means (9) comprising a flip flop mechanism (25), the said flip flop mechanism capable of operation by falling nuts (28) to the said roasting drum (1) by means of a funnel (24) to convey only desired quantity to drum roaster to ensure optimum roasting process, the said drum roasting means capable of having controlled temperature in a range of 450 to 650°C during the nut roasting process.

2. A drum roasting machine as claimed in claim 1, wherein drum roasting means is made of mild steel, stainless steel.

3. A drum roasting machine as claimed in claim 1, wherein the prime is an electric motor of typically 0.37KW.

4. A drum roasting machine as claimed in claims 1 and 2, wherein t he prime mover is driven by solar energy.

5. A drum roasting machine as claimed in claim 1, wherein the power reduction mechanism is a reduction gear with a preferred ratio of 110:1 to 58:1

6. A drum roasting machine as claimed in claim 1, wherein the heating gas is a liquefied petroleum gas sync gas, producer gas.

7. A drum roasting machine as claimed in claim 1, wherein the gas burner means is a meander type structure with small outlets.