FIELD OF THE INVENTION:
The present invention relates to a cabinet dryer for drying ginger and turmeric. Further, the present invention is adapted to dry efficiently the freshly harvested ginger and turmeric without the loss of pungency and aroma of the agro product.
BACKGROUND AND DESCRIPTION OF THE PRIOR ART:
Drying is an important post harvest operation for spices to prevent the spoilage due to water activity, mould growth etc. during storage. The batch type cabinet dryer in the present invention is adapted to dry efficiently the freshly harvested ginger and turmeric without the loss of pungency and aroma of the agro product.
Drying of ginger / turmeric is a post harvest operation required for reducing moisture content of the crop.
The moisture content of the freshly harvested ginger and turmeric is too high, in the range of 80 to 90 %. It is required to reduce the moisture level to less than 10% to preserve them safely. Drying reduces the susceptibility to spoilage caused by the growth of bacteria, moulds etc.
Reference may be made to patent no. US 3362081, "Cabinet dryer and method"wherein upright hose dryer has a chamber with perforated bottom and top walls and a recirculation dust structure in a side wall having an impeller to draw moisture laden air through said top wall, expel part of such air and recirculate the reminder of the air through the bottom wall. Fresh air is added to the recirculated air and the mixture is heated
Reference may be made to patent no. US 6928752, "Combination tumble and cabinet dryer" wherein combination tumble and cabinet dryer appliance includes a housing with a tumble dryer and a cabinet dryer therein. The tumble dryer and cabinet dryer are operable independently of one another. Separate sources of hot air are provided to each of the tumble

and cabinet dryers. The cabinet dryer extends over and along one side of the tumble dryer. A portion of the cabinet dryer extends substantially along the height of the housing so as to receive long hanging clothes, such as a dress. Removable shelves are provided in the cabinet dryer for drying sweaters and the like.
Reference may be made to patent no. US7412807/'Cabinet dryer door with truss and method of use" wherein a cabinet dryer door includes a truss attached to the door to establish seal compression for adequate sealing of the door against the drying cabinet. The inner door has spacers molded into the inner door. The truss cooperates with the spacers to bias the door against the seal. The drying cabinet may utilize a pair of doors with at least one having a truss that establishes a seal compression in both of the doors. The truss is joined to the inner door by a screw located in the center of the truss. The method has the step securing a truss member to the door and curving the door to create a biasing force.
The drawbacks, for all the above prior art references, are listed below.
The rate of drying in the above-mentioned dryers is very slow for drying of high moisture agro-crops, especially when the retention of aroma and pungency is of prime importance. The slow drying process in the case of existing cabinet dryers welcomes mould growth and infection thereby. The large-scale industrial production with required product quality through these types of dryers is not possible.
Thus it would be highly desirable to provide a cabinet dryer, which produces uniform quality product of dried ginger or turmeric at a faster rate with an optimum cost of production to ensure long storage life.
OBJECTS OF THE INVENTION:
The main objective of the present invention is to provide cabinet dryer for ginger and turmeric.

Another objective of the present invention is to provide a cabinet dryer where the hot air passes through the perforations in the trays and also in a zigzag way inside the dryer and enhance the heat and mass transfer leading to faster drying and lower electric energy consumption to produce uniformly dried ginger and turmeric.
Still another objective of the present invention is to provide an equipment where ginger and turmeric can be dried at a fixed temperature and with uniform quality throughout the drying chamber retaining the aroma and pungency fully.
Yet another objective of the present invention is to provide a dryer, which can be operated by unskilled personnel with minimum error.
still another objective of the present invention is to provide a dryer for ginger / turmeric, which is easy to be maintained and eco - friendly.
Yet another objective of the present invention to provide a dryer for ginger and turmeric, which is easy to be manufactured.
SUMMARY OF THE INVENTION:
Accordingly, the present invention provides batch type cabinet dryer for drying of freshly harvested ginger and turmeric uses fin type electric heater to generate hot air which interacts with the sliced ginger / turmeric placed in perforated stainless steel trays while moving through the perforations and over the materials in a zigzag route for intense gas solid contact to reduce the moisture content thereby preventing the loss of crop during its storage.
In an embodiment the present invention provides acabinet dryer comprising an inner stainless steel wall (1) housed in outer steel cover (2) with insulation (3) wherein the dryer within the said inner steel wall (1) is divided in three sections; the middle section (18), the upper section

(19) and the lower section (20), wherein the said middle section (18) further comprises plurality of perforated trays (5) and channels (4), and the said lower portion (20) comprises a thermocouple (6), an air heater (7) wherein the said upper portion (19) comprises a control panel(12) which further comprises a main switch (13) a secondary switch (14) a controller and display panel (15) a regulator (16) an indicator (17) and an exhaust fan (8) attached at the top, further the said dryer is enclosed within doors (9) using a rubber gasket (10) to avoid heat loss, wherein, the said assembly being placed onto a wheel mount (11).
In another embodiment the present invention perforated trays (5) are placed in a zig-zag manner for maximum heat exposure.
In yet another embodiment the present invention thermocouple (6) sens the temperature of the inlet air to the dryer.
In still another embodiment the present invention fin type air heater (7) provides heat for drying medium.
In yet another embodiment the present invention exhaust fan (8) expels moisture laden air from dryer.
In still another embodiment the present invention exhaust fan (8) expels moisture laden air from dryer.
In yet another embodiment the present invention doors (9) provide provision for closing the dryer.
In still another embodiment the present invention rubber gasket (10) prevent the leakage of drying air through doors (9).

In yet another embodiment the present invention wheel mount (11) carry the whole assembly.
In still another embodiment the present invention control panel (12) holds all switches and indicators.
In yet another embodiment the present invention main switch (13) provides power to the dryer.
In still another embodiment the present invention secondary switch (14) connects/disconnects electric power supply to the heaters.
In yet another embodiment the present invention PID controller and display panel (15) monitor and display the temperature of the drying medium.
In still another embodiment the present invention regulator (16) regulates the temperature inside the dryer.
In yet another embodiment the present invention indicator light (17) indicates the operation of the said dryer.
In still another embodiment the present invention dryer is used for drying of ginger and turmeric.
BREIF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Fig 1: Represents opened view of batch type cabinet dryer for ginger and turmeric , wherein various parts are:
1 - Inner stainless steel wall of the drying chamber which is very smooth and polished for easy
in cleaning
2 - Outer mild steel cover to protect the dryer

3 - Insulation to prevent heat loss from the dryer
4 - Channel for movement of drying air to the next upper chamber
5 - Perforated trays to hold the materials for drying
6 - Thermocouple for sensing the temperature of inlet air to the dryer
7 - Fin type electric air heater for heating the drying medium
8 - Exhaust fan for removing moisture laden air from the dryer
9 - Door for inserting trays into the dryer

10 - Rubber gasket to prevent leakage of drying air
11 - Wheel mount for easy movement / transport of the dryer
12 - Control panel to hold all the switches and indicators
13 - Main switch to start electric supply to the dryer
14 - Switch to connect / disconnect electric power supply to the heaters
15 - Controller and display for the temperature
16 - Regulator for controlling the fan speed 17-Indicator light
Fig 2: Represents closed view of of batch type cabinet dryer for ginger and turmeric.
DETAILED DESCRIPTION OF THE INVENTION:
The batch type cabinet dryer of the present invention is used to dry ginger and turmeric after harvesting. The invention is comprised of a hot air generator where fin type electric air heaters are used for heating the incoming ambient air. The hot air thus produced is utilized in the cabinet dryer as drying medium. The ginger / turmeric after required washing are sliced and placed in stainless steel trays having perforations at the bottom for passage of drying medium. Trays with ginger / turmeric are placed one above another on support structure inside the drying chamber. The gap between consecutive trays is suitably maintained for optimum drying. In the present invention the dryer consists of four chambers where two can be operable from the front and two from the rear.

The present invention is illustrated in the drawings accompanying this specification. The figures represent the present invention of batch type cabinet dryer for ginger and turmeric. The dryer consists of four independent drying chambers accessible from the front and rear through individual doors 9 where rubber gasket 10 is fitted to prevent leakage of hot air from the cabinet. The outer wall of the dryer is made of two mild steel sheet 1 and 2 separated by wood insulation 3 to prevent heat loss through wall. Four numbers, 1.0 kW each, fin type electric air heaters 7 are used to heat the incoming ambient air in each chamber and to prepare the drying media. The freshly harvested ginger / turmeric slices, having moisture content 80 to 90 %, kept in six numbers of perforated trays 5 in each drying chamber, are placed into the dryer. The hot air from the bottom heating chamber moves up through the perforation and also through the channels 4 in a zigzag way and interacts with the material to be dried before it leaves the dryer. An exhaust fan 8, mounted at the top of each chamber of the dryer, sucks the moisture-laden air out from the chamber. The airflow through the trays can be controlled by regulating the fan speed through a regulator 16. A thermocouple 6 is attached to each drying cabinet just above the heating chamber to measure the temperature of the drying air. The temperature of the drying medium is controlled by means of a programmable controller 15 mounted on the control panel 12. The control panel consists of a number of indicator lights 17 for inspection and control of the total system. The entire system is mounted on wheels 11 for its easy movement and transportation. The freshly sliced ginger / turmeric can be dried in such dryer in four to five hours to a moisture content of 8 to 10 % and can be stored safely.
The present invention comprises of a drying chamber which accommodates a number of heaters for hot air generation, trays to accommodate the materials to be dried, exhaust fans to drive out the moisture laden air, thermocouple to control the temperature of the drying medium, a voltage regulator to control the speed of hot air over and across the sliced ginger / turmeric and a control panel to accommodate all the switches, controller, indicator lights and the regulator for the purpose of drying freshly harvested ginger / turmeric. The present invention works under the following ranges of operating parameters.

(Table Removed)
Novelty of the present invention lies in the ability of the device to deliver uniform product quality at faster rate. Movement of hot air through the perforation and also over the materials to be dried through inclusion of channel slots on opposite sides and stacking the trays in zigzag way leads to better heat and mass transfer in between the material and the hot gas for faster drying constitute the non-obvious inventive steps.
A cabinet dryer in the present invention having a hydrodynamics different from those in ordinary dryer can work suitably for drying of a range of materials. In a cabinet dryer, the air is sucked in to the drying chamber by a fan installed at the top of the dryer, which again drives out the moisture-laden air from the chamber. The air gets heated in the heating chamber by fin type electric air heater to a required temperature, interacts with the materials to be dried while passing through and over the sliced ginger / turmeric to dry them to a required level and leaves the chamber carrying the expelled moisture from the material. In drying, intensive gas solid mixing results in uniform drying and thus a good product quality.

Pilot Plant Data on drying of Ginger Batch size : 60 kg
Inlet air temperature 60 °C
Ambient air temperature 30 °C
Air velocity 0.3 - 0.4 m/sec
Inlet Moisture content 85 - 90 %
Product Moisture content 8 -10 %
Moisture Evaporation 53.5 kg
Electrical Energy consumption 50 - 60 kWh
EXAMPLES:
The following examples are given by the way of illustration and therefore should not be constructed to limit the scope of the invention.
Example: 1
An experimental work is carried out in the dryer as described in table-1 for drying of ginger. Sliced ginger with moisture content of 86% (wb) is kept in the trays and placed inside the dryer. The air temperature after the heater is recorded and controlled continuously by a proportional-integral-derivative controller (PID controller). The moisture content of the materials to be dried is measured periodically by a infrared type moisture meter (Testing Instrument Pvt. Ltd., India). From the recorded data it is seen that the drying time for 60 kg of sliced ginger is around 5 hrs at a drying air temperature of 60 °C.

TABLE - 1
Ambient Relative Humidity : 68 %
(Table Removed)
Example: 2
Another experimental work is carried out in the dryer which is similar to example-1 but for the drying of turmeric. Sliced turmeric with moisture content of 87 % is kept in the trays and placed inside the dryer. The air temperature recorded and controlled continuously by a proportional-integral-derivative controller (PID controller). The moisture content of the materials to be dried is measured periodically by infrared type moisture meter (Testing Instrument Pvt. Ltd., India). From the recorded data it is seen that the drying time for 60 kg of sliced turmeric is around 5 to 5.5 hrs at a drying air temperature of 60 °C.

(Table Removed)
ADVANTAGES OF THE INVENTION:
• Uniform drying resulting in uniform product quality
• Compact in design and easy to be manufactured
• A outer mild steel cover protects the dryer from physical damage.
• An insulator prevents heat loss from the dryer.
• channels between the perforated trays provide movement of drying air to the next upper chamber.
• Less capital investment
• Low running cost
• Efficient, less energy consumption
• Controlled drying
• Faster drying
• User friendly, no specialized manpower required
• Easy maintenance
• Light indicators for indicating the operation performed.

We Claim:
1. A cabinet dryer comprising an inner stainless steel wall (1) housed in outer steel cover (2) with insulation (3) wherein the dryer within the said inner steel wall (1) being divided in three sections; the middle section (18), the upper section (19) and the lower section (20), wherein the said middle section (18) further comprises plurality of perforated trays (5) and channels (4), and the said lower portion (20) comprises a thermocouple (6), an air heater (7) wherein the said upper portion (19) comprises a control panel(12) which further comprises a main switch (13) a secondary switch (14) a controller and display panel (15) a regulator (16) an indicator (17) and an exhaust fan (8) attached at the top, further the said dryer being enclosed within doors (9) using a rubber gasket (10) to avoid heat loss, wherein, the said assembly being placed onto a wheel mount (11).
2. A cabinet dryer as claimed in claim 1, wherein the perforated trays (5) are placed in a zig¬zag manner for maximum heat exposure.
3. A cabinet dryer as claimed in claim 1, wherein thermocouple (6) senses the temperature of the inlet air to the dryer.
4. A cabinet dryer as claimed in claim 1 wherein a fin type air heater (7) provides heat for drying medium.
5. A cabinet dryer as claimed in claim 1, wherein exhaust fan (8) expels moisture laden air from dryer.
6. A cabinet dryer as claimed in claim 1, wherein doors (9) provide provision for closing the dryer.
7. A cabinet dryer as claimed in claim 1, wherein the rubber gasket (10) prevents the leakage of drying air through doors (9)
8. A cabinet dryer as claimed in claim 1, wherein wheel mount (11) carry the whole assembly.
9. A cabinet dryer as claimed in claim 1, wherein the control panel (12) holds all switches and indicators.
10. A cabinet dryer as claimed in claim 13, wherein the main switch (13) provides power to
the dryer.
11. A cabinet dryer as claimed in claim 13, wherein secondary switch (14)
connects/disconnects electric power supply to the heaters.
12. A cabinet dryer as claimed in claim 13, wherein a PID controller and display panel (15)
monitor and display the temperature of the drying medium.
13. A cabinet dryer as claimed in claim 13, wherein regulator (16) regulates the temperature
inside the dryer.
14. A cabinet dryer as claimed in claim 1, wherein the dryer is used for drying of ginger and
turmeric.
15. A cabinet dryer substantially as herein described with the reference to the examples and drawings accompanying the specification.