Rice Processing Machinery
Rice processing cycle
Rice processing consists of cleaning, color grading, polishing and packing. A series of machines perform various processes. A typical processing cycle is shown below.
Input hopper: The rice is discharged into the input hopper where it will be sent to the cleaning section. From the input hopper, this raw material is sent by means of a bucket elevator.
Bucket Elevator: Bucket elevators are used for the vertical movement of material. The Elevator is fed into the inlet and lifts the raw material through buckets, which are bolted to a belt driven by two pulleys at each end of the elevator (upper and lower end, called Head & Boot respectively). This bucket conveyor lifts the material and unloads it at the outlet spout.
Feeding Hopper: The raw material (rice) is lifted by the elevator and stored in the holding hopper (capacity 25 tons) to continue. The raw material is discharged into the receiving pit and then the pit is emptied and the raw material is stored in the container as long as it is processed.
Combination/Pre-Cleaner: The raw pulse is the first of all to be entered into the Combination/Pre-Cleaner. This machine performs the initial cleaning of the raw material and separates the different impurities. The stock is fed to the inlet that oscillates with the machine. The flow of material is directed precisely towards the center of the machine and the stock is distributed over the entire width of the screen. The upper screen removes jute threads and other larger particles. The lower screen removes light particles such as bran tips, etc. The suction channel removes dust and light particles such as husk and the separated and sucked product is collected at the outlet. Dust particles are vacuumed out of the system and collected for disposal.
Magnetic Separator: Stops ferrous material with permanent magnet arrays and is positioned in such a way that all material flows evenly distributed across the full width of its magnetic field.
Husk Separator: Separates the husk/rice grains from the rice. This separation is accomplished by passing the beans through a series of baffle compartments (usually Z-shaped) mounted on an inclined rocking table using the difference in specific gravity, surface area, grain texture, and gravity.
De-Stoner: De-stoner is used to remove stones, metals, glass and other heavy impurities from rice. It is based on and works on the principle of vacuum. The vibrating fluid bed gives a buoyant bounce to the incoming materials and therefore the pulses are continuously separated from the heavier materials based on specific gravity.
Thickness Grader: After de-stoned pulses, an elevator lifts the pulses to feed them to thickness graders which separate over/undersized beans other than super basmati pulses like kidney beans, red pulses, immature and wrinkled beans, etc. During the process, the rotating cylindrical screens discharge the undersized/oversized beans through the screen slots and the mature beans are collected separately.
polishing section
Bucket Elevator: Elevators are installed before each machine to provide the feed. First, the materials are taken at a specified height and collected in feed tanks above the machine so that a continuous flow is available to the machines for processing.
Feed Tank: Also called feed balance hoppers, conical hopper is used to provide continuous balanced feed to machinery.
Abrasive polisher: This polisher is used for pulse polishing with optimal performance. The rice passes through the polisher and the bran is removed by the polisher due to the friction between the rice paddy and the emery. The rice enters the polisher and is directed towards the chamber by a screw feeder. The intensity can be controlled by two adjustable means, the check outlet counterweights and the gap between the emery roll and the screens.
It is also equipped with a suction system to efficiently fulfill the task of cooling the vegetables and thereby reduce breakage. It also supports transport of bran out of the chamber.
Water polish: Water polish is used for final polishing of pulses to produce a glossy, smooth and dust-free surface of pulses. This machine removes loose bran and dust from beans and increases gloss through humidity controlled air and friction roller during the process. For humidity, a uniform water mist is generated with flowmeter control of air flow and drinking water.
Sorting and Color Sorting Section
Bucket Elevator: Once again, the polished pulses are conveyed vertically upward through an elevator for sorting and color grading.
Rotary Flat Screen: This machine separates small broken and long grains from the rice flow. This machine can efficiently and accurately screen ruce, heavy and light impurities, head pulse mixture, large, small and medium breaks, tops and bran, etc. The operation of the machine is more efficient when there is a clear difference in size, for example, the separation of small broken pieces of bran from pulses.
The horizontal circular motion gives the rice grains active play in the spacious area of the sieve, resulting in accurate and fast sieving. Free-moving rubber ball cleaners prevent the screen from clogging, which speeds the smooth passage of rice through the screens.
Any combination of the sieve according to the required specification, both in number of sieves and in mesh sizes, allows choosing the combination that best suits the sieving needs.
Length Grader – Designed for precise longitudinal grading and separation of rice according to notch size. The rice enters the notch cylinder at the feed inlet located at the upper end of the inclined cylinder. Undersized grain is captured by the notches and is conveyed upward as the cylinder rotates until a point is reached where the grain is dislodged by the force of gravity and collected in a flared channel screw conveyor and it downloads. And the whole grain remains at the bottom of the cylinder and is collected separately.
Two segmented indentation cylinders are used to classify rice into three categories:
– Premium legumes Full size rice within standard tolerances
– Legumes of 2nd Quality Rice size ¾
– 3rd Quality Legumes ¼ to ½ size of rice flour and legumes
Compressor: Used to supply compressed air to the color sorter and packing scales, etc. It is completed with transmission arrangements, electric motor, water filter, dryer, pressure gauge and valves, etc.
Color Sorter: Used to separate discolored grains and hull from processed rice. The color sorter is a microprocessor-controlled 256-channel automatic machine that works on the monochromatic principle of light spectrum to separate discolored grains.
Packing scale: Automatic weighing and packaging machine used to pack head legumes. Digitally designed for external control control panel, it provides highly accurate measurements. The very efficient and fast operation gives the possibility to pack in a short time compared to manual weighing and packing.
Nawaz rice engineering
