According to the working principle, fruit sorting equipment can be divided into size classifier, fruit quality classifier, fruit color classifier and fruit color quality classifier which is classified according to both size and color.
1. Fruit size classifier
A classifier that classifies according to the size of the fruit, because the size and shape of the selected fruits are basically the same, which is conducive to packaging, storage and processing, so this kind of classifier is the most widely used in fruit classification.
Working principle: The fruit is moved along the grading screen with grids or slits of different sizes, the small z fruit first leaks from the z small grid, and the larger fruit leaks from the larger grid. produce different levels of fruit. There are different tree species and varieties, different sizes of fruits, and different grades. Pears are generally divided into 3 to 4 grades, and apples are divided into 5 grades. At present, the 6GF-1.0 fruit size grading machine developed in my country adopts the advanced roller and belt gap grading principle. When working, the grading roller rotates at a uniform speed and the conveyor belt moves in a straight line. When the diameter of the fruit is smaller than the gap between the grading roller and the conveyor belt, it will fall into the fruit trough along the gap. During the working process of the machine, the fruit will fall into the corresponding level of the fruit trough through different gaps due to different diameters. Grading accuracy ≥95%, production efficiency ≥≥1.5t/h.
In order to reduce fruit collision and improve the rate of good fruit, some graders use the method of buoyancy, vibration and grid for grading. A fruit selection screen with different mesh sizes is installed on the upper part of the fruit selection tank, and a vibrating part is installed in the water tank. When sorting, the fruit is first sent into the water tank. When the vibrating part vibrates, the fruit in the tank gains kinetic energy and moves. When the fruit moves to the mesh corresponding to its size, the fruit will surface through the mesh and stay in the corresponding slot. , and then collect, that is, to complete the fruit grading process. The advantage of this method is that the collision between the fruits is avoided, and the fruits can be cleaned and disinfected while grading.
2. Fruit Quality Classifier
Grading machinery, which is graded by fruit quality, works on the principle of leverage. A fruit bucket is installed at one end of the lever. The fruit bucket and the lever are connected by hinges. The upper part of the other end of the lever is pressed by a counterweight, and the lower part has a supporting guide rod to ensure the horizontal state. The middle of the lever is supported by a hinge point. When the quality of the fruit in the fruit bucket exceeds the balance weight, the lever is tilted, the fruit bucket overturns, and the fruit is thrown out. The lever carrying the light fruit passes the position of the counterweight and continues to move forward along the guide rod. When it encounters the counterweight less than the weight of the fruit, the lever tilts, and the fruit bucket overturns and throws out the lighter fruit at the new position. Therefore, the fruit can be divided into several grades according to the quality.
At present, the advanced computer-controlled fruit quality grading machine adopts the latest electronic instruments to measure the quality, and can choose the accurate grading benchmark as needed. The grading accuracy is high, and the special chute is used. The time required for grading and packing is 1/2 of that of traditional grading and packing.
3. Fruit color classifier
The working principle of the fruit color grading machine is that when the fruit passes in front of the electronic light-emitting point, the reflected light is received by the photocell measuring the wavelength. The color of the reflected light is different, and the wavelength of the reflected light is different, and then the system analyzes and determines the choice according to the wavelength. , to achieve the purpose of grading by color. In the production of fruit storage and processing industry in Italy, color grading machine was used earlier, mainly to color grading apples. When working, the fruit jumps and moves on the soft conveyor belt, so that the light can irradiate most parts of the fruit, thus avoiding the phenomenon that the fruit is irradiated on one side and the grading accuracy is low. The reflected light is transmitted to the computer, and the computer separates the fruits according to the different reflectivity, which are generally divided into full green fruits, half green (half red) fruits and full red fruits.
4. Fruit color quality classifier
The fruit color quality grader is used to grade both the degree of fruit coloration and the size of the fruit. It adopts the world's most advanced fruit post-harvest processing technology. This machine was first successfully developed in Italy and applied to production. The working principle is to combine the above-mentioned automatic color grading and automatic size grading. First of all, the conveyor belt with variable aperture is used for size classification. A light source is installed under the conveyor belt. The fruits leaking from the conveyor belt are illuminated by the light source, and the reflected light is transmitted to the computer. The fruits that are leaked are divided into full green fruits, half green and half red fruits, all red fruits and other grades, and then conveyed out through different conveyor belts. The production line can process 15-20t of apples per hour.
