Patent ID: 7128539

Claim:
A method of cleaning a paint sprayer pump from residual paint without the addition of compressed air, the paint sprayer pump being driven by a drive, the method comprising the steps of: supplying a cleaning fluid adapted to remove residual paint to an inlet of the paint sprayer pump; predetermining a cleaning pressure range comprising a first and a second flow rate; setting a desired flow rate of the paint sprayer pump; verifying that the desired flow rate is in the predetermined cleaning pressure range; entering a cleaning cycle when the desired flow rate is in the predetermined cleaning pressure range; operating the paint sprayer pump alternately between the first and the second flow rate to cycle a flow rate of the paint sprayer pump while verifying that a power level of the drive produces a flow rate between the first and the second flow rate of the paint sprayer pump; and pumping the cleaning fluid through the paint sprayer pump to an outlet of the paint sprayer pump while the flow rate is cycling; wherein the paint sprayer pump produces increased turbulence in the cleaning fluid through an alternating pattern of increasing and decreasing flow rates achieved by the cycling of the power level in the paint sprayer pump cleaning the paint sprayer pump; and further comprising the steps of measuring actual flow rate at an outlet of the paint sprayer pump and setting a pressure flag when the actual flow rate is less than the smaller of the first and second flow rate, and wherein when the pressure flag is set the paint sprayer pump is operated.