Electrically actuated variable flow control system
AssigneeThe Regents of the University of California
InventorsDurham K. Giles, John A. Comino
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Abstract
An electrically-actuated liquid spraying system for controlling the volumetric flow through pressure-atomization spray nozzles is disclosed. Each nozzle is attached to a direct acting, in-line solenoid valve which is connected to a liquid supply at constant pressure. The valve is excited by square wave pulses of variable frequency and duty cycle to reciprocate between its fully open and closed positions and thereby control the flowrate over a range without changing droplet size and spray pattern. The frequency and duty cycle of the square wave pulses are varied and controlled by feedback data of relative target movement, size, shape and other factors as well as by gated sampling of the dynamic pressure in a region between the valve seat and nozzle orifice.
Claims10
A valve/nozzle device for spraying liquid in a predetermined pattern and at a controllable flowrate comprising:
- body means having an inlet connected to a liquid supply and an outlet source, movable means within said body means for allowing liquid flow through said outlet in a fully open first position and for preventing liquid flow through said outlet in a fully closed second position;
- actuator means for moving said movable means back and forth between said first and second positions to allow liquid to flow through said outlet intermittently in said first position;
- means for controlling said actuator means so that the time for moving said movable means from said first to said second positions is relatively brief in relation to the time spent in said fully open first position;
- and
- nozzle means connected to said body means adjacent said outlet for providing a desired spray pattern of said liquid;
- whereby droplet size spectra and spray pattern distortion of the sprayed liquid is minimized for different flowrates from said device.
A liquid spraying system for spraying a plurality of targets having different characteristics while there is relative movement between said system and said targets, said system comprising:
- target sensing means for producing signals relative target characteristics and movement relative to said system;
- process controller means for receiving and processing said signals from said target sensing means to produce output signals relative to a desired flowrate to be used for said targets;
- a nozzle device connected to a liquid supply including means for allowing intermittent on-off cycling of its liquid output from a fully open first position to a fully closed second position wherein the time for moving from said first to said second position is relatively brief in relation to the time spent in said fully open first position;
- nozzle controller means including a square wave generator for receiving said output signals from said process controller means and providing activating square wave pulses to said nozzle device at a frequency and duty-cycle which causes said on-off cycling and provides a desired flowrate while minimizing droplet size spectra and spray pattern distortion for different flowrates.
Dependencies are inferred from the claim text.