Calibration method for adjustable orifice valve

A method of using an ammonia applicator for fertilizing an agricultural field, the method comprising;

• directing ammonia from a pressurized tank along a delivery path that extends through a manifold and multiple exit lines that extend from the manifold and are arranged for delivering ammonia onto an agricultural field and including the steps of:
• installing a fixed flow restricting orifice upstream of a variable flow restricting orifice;
• measuring the pressure upstream of the fixed flow restricting orifice;
• beginning with the variable flow restricting orifice in the maximum flow condition, repeatedly measuring the pressure downstream of the variable flow restricting orifice;
• repeatedly comparing the measured downstream pressure with the measured upstream pressure;
• incrementally closing the variable flow restricting orifice after each comparison so long as the measured pressure downstream of the variable flow restricting orifice and the pressure upstream of the fixed flow restricting orifice remain substantially the same;
• recording the variable flow restricting orifice maximum flow setting when the measured pressure downstream of the variable flow restricting orifice drops below the pressure upstream of the fixed flow restricting orifice;
• and
• repeating the recited steps for each of a plurality of exit lines, sequentially establishing a maximum flow rate setting for each exit line one at a time, wherein at least two fixed flow restricting orifices provide maximum flow rates differing from one another and further that known tolerances of the fixed flow restricting orifices are not relied on.

A fluid material delivery system from a pressurized tank along a delivery path that extends through a manifold and at least two exit lines that extend from the manifold having remotely controllable variable flow orifices in each of the exit lines, the method of establishing maximum flow rate settings for each of the at least two variable flow restricting orifices, comprising the steps of:

• positioning a first fixed flow rate orifice establishing a first maximum flow rate in a first exit line upstream of a first variable flow restricting orifice;
• measuring the pressure upstream of the first fixed flow restricting orifice;
• beginning with the first variable flow restricting orifice in the maximum flow condition, repeatedly measuring the pressure downstream of the first variable flow restricting orifice;
• comparing the measured downstream pressure with the measured upstream pressure;
• incrementally closing the first variable flow restricting orifice after each comparison so long as the measured pressure downstream of the first variable flow restricting orifice and the pressure upstream of the first fixed flow restricting orifice remain substantially the same;
• and
• recording the first variable flow restricting orifice maximum flow setting when the measured pressure downstream of the first variable flow restricting orifice drops below the pressure upstream of the first fixed flow restricting orifice;
• positioning a second fixed flow rate orifice establishing a second maximum flow rate in a second exit line upstream of a second variable flow restricting orifice such that the second maximum flow rate differs from the first maximum flow rate and further that known tolerances of the first and second fixed flow rate orifices are not relied on;
• measuring the pressure upstream of the second fixed flow restricting orifice;
• beginning with the second variable flow restricting orifice in the maximum flow condition, repeatedly measuring the pressure downstream of the second variable flow restricting orifice;
• comparing the measured pressure downstream of the second variable flow restricting orifice with the measured pressure upstream of the second fixed flow restricting orifice;
• incrementally closing the second variable flow restricting orifice after each comparison so long as the measured pressure downstream of the second variable flow restricting orifice and the pressure upstream of the second fixed flow restricting orifice remain substantially the same;
• and
• recording the second variable flow restricting orifice maximum flow setting when the measured pressure downstream of the second variable flow restricting orifice drops below the pressure upstream of the second fixed flow restricting orifice.