Control system for constant pressure metering of fluid sowing machine

A control system for constant pressure metering of fluid sowing machine was developed. Fluid sowing is a new way to save water against drought, to ensure the emergence rate and growing of the seedlings of the crop. But the level of the gel and seeds mixture in the tank will lower down and the rate of gel metered will decrease with the proceeding of sowing and this will reduce the uniformity of sowing. In this study, the metering pressure in the tank was maintained to a constant value with the air blast for agitating, by adding a pressure control system of magnetic float and solenoid to the experimental machine, which solves the problems in the process of fluid sowing. The mathematic model of the air rate for stabilizing the pressure with the metering process was established which can provide basis for the parameters design of the air blowing system of metering device of fluid sowing machine. The experiments on metered gel rate with and without the pressure stabilizing control system were conducted, the results showed the control system could significantly increase the uniformity and mean gel rate metered and it can meet the requirement of agricultural production.