Potato Starch Processing Line

Raw Material Reception Unit
Raw material reception unit is the first step of potato starch processing. The main purpose of this unit is to preliminary remove impurities and put potatoes into storage pool.

When unloading potatoes, it is better to use special shovels to prevent the potatoes from damaging. Potato storage time can't exceed half a month. The longer the potatoes are stored, the more adverseness for the starch production.

Attention must be taken that potatoes should not be damaged when purchasing them. Damaged potato is perishable, and the rotten potato will affect the potatoes around easily. The quality of potatoes has very big influence on the quality of potato starch.

Hydraulic Transporting Unit
The main purpose of this unit is to convey potatoes in the potato storage tank into conveying screw elevator by flow conveying, and then convey them to a de-stoner through a flow trough. In the process of conveying, potatoes continuously roll and clash in stream flow to peel off sticky mud of potato, and it plays a very good cleaning role.In the production of starch, the cover of the flow groove which is near the outlet end of the potato storage tank is opened, and then washing water is pumped into it from the other end of the flow groove. Potatoes enter into the de-stoner evenly through flow conveying along the flow trough. A sluice valve is equipped in the outlet end of the flow trough, by regulating valves open degree to control the proportion of potatoes and water in the whole flow trough and evenly conveying them into the de-stoner to ensure efficient working of the de-stoner. In order to guarantee potatoes to be able to pass flow trough smoothly, a jet of water from circulating pond is pumped to impact and convey potatoes, to ensure the potatoes won't be jammed. Smoothness, shape and slope of a flow trough are crucial for the drifting of potatoes. The bottom of the flow trough designed by us is half round and the slope is reasonable, The flow trough can convey potatoes evenly into the de-stoner. A washing and conveying pump is added separately which can ensure the flow trough not being air-logged under improper operation circumstance.

De-stoning and cleaning unit
Can raw materials for potato processing play an important role, so de-stoning and cleaning unit of pretreatment stage is the most important. The purpose of this unit is to get rid of sandstone, clay of the potatoes, and to deposit cleaned potatoes in the potato temporary hopper.

Potato convey into the inverse spiral de-stoner by water to undertake cleaning and de-stoning. De-stoner is divided into two sections, the de-sanding drum and the cylindrical screen; the screen opens screen holes on the technique requirements.

When the de-stoner is working, the sand less than screen hole diameter, leaks to the sieve cylinder outside from screen holes, goes forward upstream under the action of inversion spiral belt of the sieve cylinder outside wall, falls into the sand catcher in front of the de-stoner, then the sand is discharged to a stone and impurities discharge outlet through adischarging sand plate by a sand dump drum. Larger diameter stone, brick and other heavy impurities, owing to no floatation, can stick on the wall after entering into the sieve cylinder, go forward upstream under the action of inversion spiral belt of the sieve cylinder inside and fall into the sand catcher, and then are discharged with smaller sand together.

Potatoes will be conveyed into a rotary drum washer through a flow trough and a de-watering grille by water for cleaning.Rotary drum washer works under a low liquid level condition, and cleans potatoes thoroughly. In order to achieve a good washing effect, potato tubers are cleaned through strong friction and collision between them, with the rotating of the drum.Meanwhile clean cleaning water is feeding from the material discharge outlet of the rotary drum washer, water flow discharges dirty water and potato skins and so on upstream from raw materials feeding inlet of the rotary drum washer. Cleaning water can be conveyed to the flow trough by circulating pump as conveying water, to achieve the purpose of recycling.

Washed potatoes come out from the rotary drum washer, and fall onto a screw conveyor with spray. Several rows of nozzles scatter evenly above the screw conveyor; fresh water sprays on potatoes through certain pressure to further take away dirty water of the potato surface. Cleaning water can drain to the collection trough through the net belt under the conveyor belt, and convey p for recycling. The final cleaned potatoes are conveyed into potato temporary storehouse by a screw conveyor after spraying. Potato storehouse capacity of general design can be to store one to two hours of quantity. The screw conveyor of special design can guarantee the potato storehouse can be fully filled with raw materials.

At the bottom of the potato warehouse links a discharging outlet of special design which connects a feeding spiral with adjustable speed. Feeding spiral has three outlets, two rasper connectors and one overflow outlet. A length of short connection withgate valve is between rasper and feeding spiral. When the system is to feed, the gate valve of therasper is turned on first, next the feeding spiral frequency is adjusted according to need, and then the feeding spiral isstart-up and beginning feeding. Potato slurry below the rasper is pumped into de-sanding unit with a fiber pump.

The stainless steel rasper with special design is easy to operate. Concise file clamping system ensures the file working in its best position. Loading and unloading of the file is very simple, need not use special tools, ordinary staff can accomplish it. Stainless steel sieve plate is a whole structure and can be replaced without tools, and it can make rasper reach the highest efficiency and get high starch extraction rate. The distance between the file and the fixed block is1 ~ 2mm, ensuring higher rasping efficiency. The whole production line capacity can be adjusted through the feeding spiral with adjustable speed.

Hydro-cyclone and De-sanding Unit
Potato slurry got from rasping is pumped into the de-sand cyclone through a fiber pump. Materials with certain pressure enter into the de-sand cyclone along the tangent, potato slurry in the hydro-cyclone is rotating with high-speed Light.

Starch and potato residue etc. overflow from the top of the hydro-cyclone, while heavy sand is discharged from the bottom of the hydro-cyclone. At the bottom of the ceramic vortex tube has a sand catch pot which connects pressure recoil waterto guarantee starch not being discharged from underflow outlet, and the sand in the sand catch pot is discharged regularly through two air valve.Ceramic vortex tube of special manufacture is durable; the air valve with unique design can automatically discharge sand periodically.

Entrifugal Extraction Unit
Centrifugal extraction unit is another key units of the whole production line to influence potato starch extraction rate, good centrifugal screen and process technology can help extract out all the free starch from broken potato cells.

Extraction unit is a centrifugal sieve group composed by three centrifugal sieves, each centrifugal sieve equips with a fiber pump and a de-foam pump. Potato slurry came from de-sander enters into the first level extraction sieve, under the action of centrifugal force of sieve basket high speed rotating , potato starch goes through the screen, and the residue stayed on the surface of sieve basket was thrown away lately. The front of the sieve basket, has certain pressure flushing water which spays from nozzles to make potato residue roll continuously, and then extract starch of potato residue thoroughly. Sieve basket back also designs flush water, but the back recoil water is periodically opened to guarantee pectin and potato residue non-clogging screen. Starch milk is pumped to hydro-cyclone for washing by de-foam pump, and potato residue is pumped to the second stage centrifugal sieve by fiber pump. Potato residue containing some potato starch is extracted further in the second centrifugal sieve, starchy water is pumped into the process water of the extraction unit by de-foam pump, potato residue sequentially is pumped to the third stage extraction sieve by fiber pump. Similarly, the third stage extraction sieve still carries on starch extraction, screened materials still enter the process water of extraction unit, and potato residue is pumped to potato residue dehydration unit.

The three-level of centrifugal screen group ensure all free starch was collected to the extraction system, making potato slag does not contain free starch, which guarantees the extraction rate of starch. Unique process design and excellentequipment performance guarantee that we can be completely from potato slag extract free starch.

Potato Residue De-watering Unit
Potato residue pumped from the extraction unit proceeds with de-watering by a centrifugal sieve, the working principle is the same as an extraction sieve. Potato residue finally is delivered out of the workshop through a screw conveyor, and the water of potato residue still returns to process water system of extraction unit.