Method and means of presetting the output rate of a centrifugal pump agricultural metering system

Abstract From the Canadian patent

A system and method for metering the application of liquid agricultural chemicals to the soil from a moving vehicle at a substantially constant preselected application rate, e.g. gallons per acre substantially independent of vehicle speed. The system uses a centrifugal pump driven at a rate substantially linearly proportional to vehicle speed and having its outlet pressure substantially proportional to the square of its speed. The pump receives liquid from a supply tank and delivers it to liquid discharge orifice means the rate of flow through which is substantially proportional to the square root of the pressure thereon. The system also includes a line having adjustable orifice means …