rice processing machinery
rice processing cycle
Rice processing consists of cleaning, color sorting, polishing, and packaging. 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 feeds into the inlet mouth and lifts the raw material through the buckets, which are screwed to a belt driven by two pulleys at each end of the elevator (upper and lower end, called Head & Boot respectively). This bucket belt conveyor lifts the material and discharges 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.
Blend/Pre-Cleanse: The raw pulse is the first of all to be introduced into the Blend/Pre-Cleanse. This machine performs the initial cleaning of the raw material and separates the different impurities. Stock is fed to the inlet which swings with the machine. The material flow is precisely directed towards the center of the machine and the stock is distributed across the full width of the screen. The top screen removes jute threads and other larger particles. The bottom screen removes light particles like bran tips etc. The suction channel removes dust and light particles such as hulls and the separated, aspirated product is collected at the outlet. Dust particles are sucked out of the system and collected for disposal.
Magnetic separator: stops the ferrous material with the permanent magnet arrays and is placed in such a way that all the material flows evenly distributed throughout the width of its magnetic field.
Husk Separator: Separates the husk/rice grains from the rice. This separation is achieved by passing the kernels through a series of baffle compartments (usually Z-shaped) mounted on an inclined rocking table using the difference in specific gravity, surface area, kernel texture, and gravity.
De-Stoner: De-stoner is used to remove stones, metals, glass and other heavy impurities from rice. It is based and works on the vacuum principle. The vibrating fluid bed gives a buoyant bounce to the incoming materials and thus the pulses are continuously separated from heavier materials based on specific gravity.
Thickness Classifier: After boning the pulses, an elevator lifts the pulses to feed them to thickness graders that separate the over/undersized beans other than super basmati pulses such as kidney beans, red pulses, immature and shriveled beans, etc. During the process, rotating cylindrical screens discharge the smallest/oversized beans through screen slots and mature beans are collected separately.
polishing section
Bucket Elevator: Elevators are installed before each machine to provide the feed. Materials are first picked up at a specific height and collected in feed tanks above the machine, so the machines must have a continuous flow for processing.
Feed Tank: Also called feed balance hoppers, conical hoppers are used to provide continuous, balanced feed to machinery.
Abrasive polisher: This polisher is used for pulse polishing with optimum performance. The rice passes through the polisher and this removes the bran due to the friction between the rice paddy and the emery. The rice enters the polisher and is directed into 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 transporting bran out of the chamber.
Water Polisher: Water polisher is used for final polishing of pulses to produce a shiny, smooth and dust free pulse surface. This machine removes loose bran and dust from pulses and increases gloss through humidity controlled air and friction roller during processing. For humidity, a uniform water mist is generated with flow meter control of air flow and drinking water.
Sorting and Color Sorting Section
Bucket Elevator: Once again, the polished pulses are transported vertically upwards through an elevator for grading and color sorting.
Rotating Flat Screen: This machine separates small broken and long grains from the rice flow. This machine can efficiently and accurately sieve ruce, heavy and light impurities, mixing head pulses, large, small and medium breaks, tips 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 pulse bran.
The horizontal circular motion gives the rice grains active play in the spacious sieve area, resulting in accurate and fast sifting. Free-moving rubber ball cleaners keep the screen from clogging, speeding up the smooth passage of rice through the screens.
Any combination of the sieve according to the required specification, both in number of sieves and mesh sizes, allows choosing the combination that best suits the sieving needs.
Length Sorter: Designed for precise longitudinal sorting 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 conveyed upward as the cylinder rotates until a point is reached where the grain is dislodged by the force of gravity and collected on a flared channel screw conveyor and is downloaded. And the whole grain remains at the bottom of the cylinder and is collected separately.
Two cylinders of segmented indentation are used to classify the rice into three categories:
– Premium legumes Full size rice within standard tolerances
– Legumes of 2nd Quality Rice size ¾
– Legumes of 3rd Quality ¼ to ½ size of rice flour and legumes
Compressor: Used to supply compressed air to color sorter and packing scales etc. It is complete with transmission arrangements, electric motor, water filter, dryer, pressure gauge and valves, etc.
Color Sorter: Used to separate discolored grains and husks 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.
Packaging scale: Automatic weighing and packaging machine used to package head vegetables. Digitally designed for external control control panel, it gives very accurate measurements. Very efficient and fast operation gives the ability to pack in a short time compared to manual weighing and packing.
Nawaz Rice Engineering