There is no uniform percentage deviating from the specific model and test conditions. Gear pumps, diaphragm pumps, and pressure drums have different discharge mechanisms and cannot share a “standard error per minute”. Gear pumps are generally more suitable for quantitative delivery when the speed, viscosity, inlet feeding and back pressure are stable; diaphragm pumps and pressure drums are more susceptible to pulsations, air pressure, back pressure, valve state and paint viscosity changes. If there is no flow meter or closed-loop control, the set value of the equipment panel cannot be directly equal to the actual discharge rate per minute. Formal acceptance shall be evaluated for minute repeatability, set accuracy, long-term drift, and batch consistency under fixed paint, temperature, pressure, line, and operating time by weighing method or calibrated flow meter, respectively.
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