Abstract: The paint throughput quantity of a motor-driven throughput control valve of a paint spraygun is set such that first, a sequence of assignments between throughput quantity values and electric valve motor actuation signals is produced and input into a microcomputer as an approximation table. By selecting the desired value of throughput quantity, the microcomputer is then initialized to supply the tabularly-appertaining actuation signal to the valve motor as a control signal and to therefore approximately set the throughput control valve to the desired reference value. Finally, the throughput quantity is continuously measured during paint flow through the throughput valve and the measured values are supplied to the microcomputer as actual values, the microcomputer then supplying regulating signals to the valve motor on the basis of a comparision between the reference values and the actual values and therefore continuously readjusting the throughput control valve to the reference value.

Abstract: An airless spray gun includes a pump piston and a drive arrangement formed of a coil and a swinging armature for connection to an alternating current network. A suppression circuit is provided for periodically suppressing an arbitrarily selectable whole number of successive half-waves of the alternating current. A plurality of phase control circuits corresponding in number to the number of suppression stages is also provided, each of the phase control circuits effecting a phase-angle of fixed size and being permanently connected to one of the suppression stages to supply a phase-delayed signal of selected frequency to the drive arrangement.

Abstract: An electrical feed and control circuit for a drive arrangement of the pump piston of a spray gun which comprises a coil and an oscillating armature, employs an input for connection to an alternating current network, an output leading to the oscillating armature coil, a half-wave suppression circuit optionally connectible by way of a transfer switch, a phase-angle control circuit connectible and disconnectible by the transfer switch in common with the half-wave suppression circuit, the phase-angle circuit including a timing element comprising a fixed resistor and a capacitor, and a second phase-angle circuit -having a timing element containing a variable resistor.