Method and apparatus for flow control of NH.sub.3
First Claim
1. A method for controlling the amount of NH3 applied to a field from a nurse tank located on a vehicle, comprising:
- withdrawing NH3 from an outlet of the nurse tank;
measuring the flow rate of the NH3 with a flow meter positioned downstream from the outlet on the nurse tank;
comparing the measured NH3 total flow measured by the flow meter to the actual NH3 withdrawn from the nurse tank over a time interval;
deriving a vaporization correction factor based on measured NH3 total flow and actual NH3 total flow;
in response to the measured NH3 flow rate and the derived vaporization correction factor, determining the actual NH3 flow rate; and
adjusting the amount of NH3 applied to the field in response to the determined actual NH3 flow rate.
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Accused Products
Abstract
The present invention provides an apparatus and method for accurately controlling the amount of NH3 to be applied to a field by measuring the NH3 flow rate without condensing or cooling the NH3. The system includes a control station 12 on the vehicle with a tachometer 12A or a GPS system for providing a vehicle speed signal to a control panel 13. The control panel includes a toggle switch 17 for adjusting the opening or closing of a valve 52 in the flow line to regulate the flow through the system, although the control panel alternatively may automatically control the valve 52. The vehicle transports a tank 20 containing liquid NH3 and a tool bar 30 for distributing the NH3 to the soil. After flowing through the flow meter 40, 60, 130, the NH3 is conducted to the soil through a series of hoses, fittings, a distributor, and tubing. The flow meter transmits a signal to the control panel, which is converted to a corrected flow rate signal in response to a fixed value vaporization correction factor. The temperature of the NH3 is also measured to correct for density variations. An improved variable area meter 60, 130 uses a hall effect sensor 72 and a magnet 68 mounted on a rotatable vane shaft 70 to overcome problems with prior flow meters. The improved meter 60, 130 is ideally suited for measuring the fluid flow of a low temperature vaporization liquid, such as anhydrous ammonia, propane and butane.
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Citations
20 Claims
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1. A method for controlling the amount of NH3 applied to a field from a nurse tank located on a vehicle, comprising:
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withdrawing NH3 from an outlet of the nurse tank; measuring the flow rate of the NH3 with a flow meter positioned downstream from the outlet on the nurse tank; comparing the measured NH3 total flow measured by the flow meter to the actual NH3 withdrawn from the nurse tank over a time interval; deriving a vaporization correction factor based on measured NH3 total flow and actual NH3 total flow; in response to the measured NH3 flow rate and the derived vaporization correction factor, determining the actual NH3 flow rate; and adjusting the amount of NH3 applied to the field in response to the determined actual NH3 flow rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for controlling the amount of NH3 applied to a field from a nurse tank located on a vehicle, comprising:
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withdrawing NH3 from an outlet of the nurse tank; measuring the flow rate of the NH3 with a flow meter positioned downstream from a withdrawal valve located adjacent the outlet of the nurse tank; comparing the measured NH3 total flow measured by the flow meter to the actual NH3 withdrawn from the nurse tank over a time interval; deriving a vaporization correction factor based on measured NH3 total flow and actual NH3 total flow; in response to the measured NH3 flow rate and the derived vaporization correction factor, determining the actual NH3 flow rate; and adjusting the flow rate of NH3 applied to the field in response to the determined actual NH3 flow rate. - View Dependent Claims (10, 11, 12, 13)
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14. A method for controlling the amount of liquid applied to a field from a tank located on a vehicle, comprising:
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withdrawing liquid from an outlet of the tank; measuring the flow rate of the liquid with a flow meter positioned downstream from the outlet on the tank; comparing the measured liquid total flow measured by the flow meter to the actual liquid withdrawn from the tank over a time interval; deriving a vaporization correction factor based on measured liquid total flow and actual liquid total flow; in response to the measured liquid flow rate and the derived vaporization correction factor, determining the actual liquid flow rate; and adjusting the amount of liquid applied to the field in response to the determined actual liquid flow rate. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification