1) Shell breaking principle by impact method: The force of a nut in a shell breaking machine (such as a centrifugal or plate breaking machine). The centrifugal shell breaker makes the nut produce a large centrifugal force to hit the wall surface, and the wall faces the nut to generate the same reaction force F (for the plate-type shell breaker, the impact force F of the plate on the nut). Set the impact force F to deform the shell to δ, and form cracks in the shells A, B, and C. The elastic deformation force of the shell causes the nut to leave the wall surface, and the nut continues to move due to the effect of the inertia force and generates elastic deformation on the deformed part close to the shell. Therefore, when the nut leaves the wall surface, because the shell and the nut have different elasticities and their movement speeds are different, the nut has a smaller elastic force and a lower movement speed than the shell, which will prevent the shell from moving rapidly outward and cause the shell to crack at the crack. In this way, after multiple impacts, the shell ruptures in many places. At the same time, due to multiple impacts, some nuts may be broken.
2) Principle of shell breaking by milling: The condition of the nuts being crushed and sheared by the disc shell breaking machine. The nuts are strongly rubbed between two relatively moving grinding plates A and B, and the shell is thinned by the grinding plates. At the same time, the teeth on the abrasive disc continuously cut the shell, and finally achieved the purpose of breaking the shell. Nuts in the disc shell breaker are repeatedly crushed by the grinding plate to increase the crushing, which will produce a large amount of powder.
3) Shearing and peeling principle by cutting method: For the working condition of the knife-plate shell breaker, the cottonseed with a high elasticity and toughness outer shell and short fluff has a better shell-breaking effect with a knife-plate shell breaker. The cottonseed is subjected to the shearing force of the relatively moving blade N between the fixed blade holder A and the drum B of the knife-plate shell breaker, and the cottonseed shell is cut open, and the shell is separated from the nut. In the knife-plate type shell breaker, although the cottonseed is also subjected to the repeated action of the rotating blade, it is not continuous. It can only be cut when the fixed blade and the movable blade meet. Therefore, the nut is relatively complete, but the productivity is Lower.
4) Extrusion shell breaking principle: It is the working condition of the pressure roller shell breaking machine. A and B are a pair of grooved pressure rollers. They rotate at different speeds. After entering the gap between the two pressure rollers, the raw materials are compressed by the pressure of the rollers, causing compression deformation. At the same time, the roller surface The grooved tooth tips on the wedge are wedged into the raw material shell, which causes the shell to rupture. The shell will rupture under the action of extrusion and shear, and the nuts will plastically deform under the action of extrusion without breaking or less breaking. The cracked shell is subjected to shear and impact forces at the same time, so that the shell and the nuts are completely separated after passing through the gap between the pressure rollers.
3. Structure composition and process route
1) This production line is mainly composed of walnut classifier, vibration feeder, hoist, walnut kernel classifier, shell kernel separator, fan and so on.
2) Process route and introduction
Process route: This production line is a walnut processing production line integrating walnut classification, shell breaking, shell and kernel separation, and walnut kernel classification. The process route is shown in Figure 1
Figure 1 Process of walnut shell breaking and shell kernel separation
Process route introduction: (1) Classification before shell breaking. The walnut shell breaking machine in this production line uses the method of constant gap extrusion to achieve shell breaking.
(2) Broken shell. The walnut is lifted vertically to the walnut shell breaking machine to complete a shell breaking. For walnuts with incomplete shell breaking, after passing through the walnut kernel classifier, the walnut is lifted to the secondary shell breaking machine through a scraper to circulate. (3) Classification of walnut kernels. After the walnuts are broken, they fall into the walnut kernel classifier from the outlet of the primary and secondary shell breakers. Walnut kernels and shells are classified by grading sieves with sieve holes of different sizes during the movement.
(4) Shell and kernel separation. After one walnut kernel classifier and two walnut kernel classifiers, walnut kernels are divided into 1/2 kernels, 1/4 kernels, 1/8 kernels, 1/16 kernels, and so on. A shell and kernel separator is connected at the exit of each grade. The principle of the shell and kernel separator is to adjust the air flow according to the different suspension speeds between the walnut kernel, the shell and the diaphragm, and separate the shell and diaphragm from the nuts. The respective discharge ports exit the body.
4 main technical and economic indicators
Technical and economic indicators of the production line (depending on the size of the production line) Productivity (kg / h) The number of classifications 300 to 3 600 is 100 to 1,200 times that of labor 3 to 7 Level supporting power (kW) 15 to 30