1. The swirl tube is usually shaped like a long cone. Most of them are made of nylon, and some of them are made of other materials that are easy to process. The vortex tube is made using the principle of fluid mechanics. When there is a certain amount of pressure in the slurry, from the tangential direction of the inlet to the swirl tube, the pulp and starch in the slurry begin to produce high-speed rotational flow along the inner wall of the swirl tube. The movement speed of starch granules is greater than that of water and other light impurities. In the variable diameter swirl, the starch granules and some water form the circular slurry water column, which is adhered to the direction of the tapered inner wall to gradually decrease in diameter.
In the vicinity of the center axis of the swirl tube, a core-shaped water column with the same rotation is produced, which is slightly lower than the outer ring slurry column. The light weight in the slurry (less than 1) will be concentrated in the center of the core.
Due to the bottom hole flow area is lesser, water gushed out when the bottom hole flow in annular slurry, produced by the reaction force, ACTS on the core in the middle of the water column, the core water column to the overflow hole movement, and poured out of the overflow hole.
Dejuice is used in swirl tube, usually slightly larger. The diameter of the inner cone hole is 12~ 20mm, the diameter of the bottom hole is 3~5 mm, the diameter of the overflow hole is 4~6 mm, and the unit area of the inlet is 50 litres/mm per hour. Working pressure is not less than 0.4 mpa, the best working pressure is 0.6MP. The size of work pressure is related to the taper hole taper.
2. The operating capacity of the cyclonic cyclone is small, and the working capacity is less than 1000 liters per hour. Common specifications for: (1) for small granular starch (such as corn starch, in the size of the particles to separate the refined kudzu root starch production line of small particles of kudzu root starch) work capacity of 300 liters/hour 10 mm vortex tube; (2) a 15mm swirl tube used for the removal of puerariae starch and delicate working capacity of 500 litres/hour; (3) the working capacity of the slurry separation of the whole swirl process is 1, 000 litres/h of 30mm and the working capacity is 25mm swirl tube of 750 litres/hour.
In the practical application, a lot of vortex tubes need to be combined together to work together. The vortex tube is composed of many branches (from a dozen to more than 100), as well as plywood and housing.
3. The rotary flow station cyclone and the pump of the supply cyclone slurry constitute the first level cyclone station. A number of cascaded current stations, which are scientifically woven together to complete the dejuice and subsequent refinement, are called multistage cyclone stations. There are several levels of rotary flow stations, such as the five - stage dejuice cyclone station, the nine - level refining cyclone station, and the 10 - level cyclone station.
The main purpose of the rotary flow station is to separate the light impurities (including fine fibers, proteins and Browning substances) from the starch granules. Embodied in: the total into the slurry flow in two, the bottom part flow out of the part of the vast majority of starch and water (mixed juice), the overflow section for the vast majority of water (there is also a mixed juice) and very small amounts of starch (less than 1%, or less). Because of this, the separation ability of single-stage cyclone station is not very high, generally 48%~60%. The details vary depending on the form of the connection. There are two types of interstage connection of cyclone station: pure series and countercurrent washing.
(1) the cascade connection form of pure series pure series is divided into two types: reduced flow series and constant flow.
Reduced flow in series: the back level of the cyclone station is only through the connection form of the undercurrent of the previous level, which is called the reduced flow series. The flow at the back level is 1/2 of the previous level. This series method is also called concentrated series. Due to the limitation of the concentration range of the cyclone, in normal circumstances, there are not many series of cascaded series, generally 1~3. The reduction of flow in series is more than the end and end of the flow station. When the starch slurry concentration is low (< 3 baume degree), the head of the cyclone station can be used in series to increase the size of the slurry concentration. When the lower working procedure requires a higher concentration of starch slurry, the end of the swirl station can also be connected by reducing the flow in series. However, the amount of starch carried by the overflow of the cyclone station will increase when the concentration of slurry increases.
Constant flow in series: the amount of the amount of the feed is equal to that of the concatenated cyclone station, which is to add water between the rotational flow station. This kind of connection is called the equal flow series. When the flow is in series, the separation effect is improved obviously due to the addition of a lot of water.
(2) counter-current washing counter-current washing is also a kind of waiting flow series connection form, except that it is not water, but the overflow fluid of the lower cyclone station. Because the concentration of light material in the lower overflow liquid is lower than the concentration of light material in the size of the pulp, it can be used as the level of water for waiting flow.
Counter-current washing, water-saving effect is obvious, but the separation effect is reduced, and the base of cyclone station needs to be increased to meet the requirements of separation.
4. Refined cyclone station.
The multistage cyclone station of the refining section is the same as the multi-stage swirl station of the dejuice section, except the base is more, generally 5~15. The specific series is different due to different requirements for starch quality. Most of the refined cyclone stations are connected by counter-current washing, but only at the first and final stages.
In order to improve the separation effect, the pueraria starch was divided into two kinds: granule and small particle. Separation of large granulated starch, using a 15 mm swirl tube; Separate small granulated starch and use 10 mm swirl tube. Size of grain starch separation, also are done by cyclone, just vortex tube structure is different, the main change is that reduces the size of bottom hole, the purpose is to force the small granular starch overflow the overflow hole.
The final slurry of the two swirl stations separated by size particles is still flowing together to move into the next process.
5. Full cyclone flow station.
The sieving, dewatering and refining of the starch production line are all completed by the cyclone station, which is called the full swirl process.
The whole spinning process has the advantages of simple and practical process, good consistency of machine equipment, small occupation area and easy maintenance and management. But at present, it is mainly used for potato starch processing, and starch quality is not ideal, mainly white index is low, only about 85%. The main reason: one is that the cyclone station series is insufficient; Secondly, excessive emphasis on water conservation, resulting in insufficient washing separation strength; Third, the cyclone USES ordinary carbon steel; The fourth is the refined part (from level 3 to level 9), and the swirl tube used is large. These are the aspects that need to be noticed and improved when the whole process is introduced into starch processing.
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