The air suction precision seed drill is an energy-efficient multi-purpose precision seed drill that is 50% more than the conventional drill. The air suction precision seeding machine mainly consists of a frame assembly, a ground wheel assembly, a four-bar mechanism, a seed meter assembly, a fertilizer discharger assembly, a seed opener assembly, a fertilizer opener assembly, and a covering soil. The assembly, the reeling wheel assembly, the intermediate transmission assembly, the fan assembly and the fan actuator assembly, etc., can complete multiple processes such as ditching, fertilizing, sowing, covering soil, and pressing, and the row spacing and plant spacing. , sowing depth, fertilizer release amount, soil cover volume, town pressure, etc. can be adjusted in a wide range, and have greater adaptability. Replace different seed trays on the gas suction metering device to finely sift corn, sugar beet and alfalfa. Various crops such as hemp, soybeans and sorghum. The key technology of air suction sowing is to be able to reliably separate seeds and accurately seed them. Now, the vertical disk air suction metering device is taken as an example to explore ways to improve the accuracy of seeding.

1. Working principle of vertical disc air suction metering device

The air suction chamber of the vertical disc air suction type meter is connected with the air inlet of the fan, one side of the seed tray is the negative pressure channel of the air suction chamber, and the other side is the filling area. When the fan rotating at a high speed generates a negative pressure, the ground wheel drives the seed tray to rotate. When the seeding holes on the seed tray are turned to the seed chamber filling area, the seed chamber is open to the atmosphere, and the seed is adsorbed on the seed holes. When the seed tray is transferred to the seeding area, the negative pressure disappears and the seed falls into the groove of the opener by gravity. The seed meter is equipped with a serrated scraper that scrapes off excess seeds to meet the requirements of precision seeding.

2. Influencing factors of unstable seed volume

The main reasons for the instability of seed volume are as follows: First, there is a problem with the suction line. Where there are air leaks in the suction line, such as loopholes, loose joints, cracks, etc., the air pressure drops, the suction decreases, and some or all of the leaks are broadcast, mainly because the individual ridges are reduced or missed. Second, there is a problem with the quality of the hose. The suction hose has poor quality, aging, damage, loopholes or separation from the layer, which increases the airflow resistance, lowers the air pressure, makes it difficult to adsorb the seeds, and reduces the amount of seed discharge or leakage. Third, there are problems with the bearings on both sides of the fan. Severe wear, long-term disrepair or long-term lack of oil, resulting in increased resistance, decreased speed, insufficient air pressure, the performance of the whole machine is insufficient or completely missed. Fourth, there is a problem with the fan speed. The fan speed is insufficient and the suction is not enough. The main engine speed is reduced, the power output shaft is faulty, the triangular belt is old, the wear is severe, the length is long, the string is loose, etc., which will cause the fan speed to drop. Fifth, there is a problem with the seed tray. The seed tray is deformed due to improper storage and installation, rust or seed chamber deformation, etc., so that the seed tray and the seed chamber are not well sealed, resulting in air leakage, resulting in insufficient seed suction; the seeds are mixed with debris, and the seed holes are arranged. Blocking the dead, causing leakage sowing; improper seeding plate type, the hole is too small, the suction is insufficient, resulting in the inability to adsorb seeds or less suction, resulting in leakage or insufficient amount of broadcast.

3. Measures to improve the accuracy of the seed meter

If the phenomenon of leakage is found, stop the engine immediately and turn the planter down to check the cause. If the joint is not securely connected, it can be re-attached; if there are small holes or cracks, the tape can be used for repair. If the hole is too large or the crack is too long, the new pipe should be replaced; if the delamination resistance of the inner wall of the gas pipe is large, the new pipe should be replaced. The deformation of the seed tray or the seed chamber can be tested. After the leveling, the air leakage should be replaced. If the engine speed is normal and the fan air volume is insufficient, check the fan bearing. If there is any turbulence or noise, replace the bearing.

If the seeding machine is not sown at all, it is mainly caused by serious wear or improper transportation and storage, which causes deformation of the transmission parts, such as square shafts, bushings, bevel gears, and seed metering devices, which cause severe wear and deformation, resulting in insufficient wind speed and air volume and no seeding at all. At this time, it is necessary to comprehensively overhaul the planter. For example, the square shaft should be straightened, and the loose gasket can be used to eliminate the gap. If the wear is serious, it should be smoothed after welding. If the bevel gear is worn too much, it must be replaced in pairs. If the wear is not too serious, the gap can be removed in the inner hole. The knuckle can be padded by the welding method and then the surface is flat. It should be flexible after loading. The seed meter should be replaced. Pay attention to the lubrication of the square bushings and shafts and bevel gears during maintenance to reduce wear. Prevent collisions during transportation.

In order to improve the accuracy of the metering device, the following points need to be made: First, select an appropriate seeding adsorption hole. The size of the seeding adsorption holes affects whether the seed can be accurately and stably adsorbed on the surface of the seed tray. Tests have shown that the preferred pore size is 0.5 to 0.7 times the diameter of the seed. The second is to choose the appropriate operating speed. The speed of the work changes the linear velocity of the seed and increases the inertia of the seed, thereby affecting the seed's adsorption force. The greater the speed of the operation, the greater the adsorption of the seed. The third is the appropriate vacuum chamber vacuum. The suction chamber vacuum chamber is composed of a suction chamber and a seed tray. The degree of vacuum is directly related to whether the seed can be adsorbed on the surface of the seed tray. It forms a dynamic balance with gravity, seed inertial force, friction force and centrifugal force. Make sure the air suction meter is working properly. In order to maintain a stable vacuum in the air suction working chamber, there is a certain proportional relationship between the leakage area around the seed tray and the area of ​​the adsorption hole of the seed disc and the cross section of the air flow line. When the sum of the area of ​​the adsorption holes exceeds a certain value, The suction chamber will not form enough vacuum, causing the machine to malfunction. When the adsorption hole is adsorbed to the seed, the degree of vacuum will rise, and the adsorption hole does not fill the seed, which will greatly reduce the vacuum of the suction chamber, making the suction more difficult. The adsorption capacity of the seed can be greatly improved by sealing the gas suction pipe joint, precisely combining the seeding tray and the suction chamber, and selecting appropriate adsorption holes. The fourth is to use a scraping device. The function of scraping the seed is to collide the excess seed adsorbed, thereby stabilizing the seed on the adsorption, thereby improving the single particle separation rate of the air suction metering device. Fifth, the design of the seed chamber cavity should be reasonable. When the seeds are in a loose state, the friction between the seeds will decrease, and the overhead phenomenon will rarely occur, which is beneficial to seed adsorption. In order to keep the seeds loose and able to replenish, the design of the seed chamber cavity is important. First, the adsorption chamber and the seed storage chamber are separated, and a separator is designed in the adsorption chamber so that the seeds can be smoothly replenished without affecting the adsorption effect of the seeds. Secondly, a stirring mechanism is designed in the adsorption chamber to minimize the inability to adsorb seeds due to overhead.