Abstract: In a fluid-pumping system comprising a pump and a pulsation dampener, which is arranged to dampen pressure pulsations, the pump is driven by a piston and motor. The pulsation dampener is arranged to be charged via an associated regulator, which is arranged to regulate the charging air pressure by reference to the average pressure of the fluid exiting the pump. Preferably, the pulsation dampener comprises two apertured walls, between which a diaphragm is mounted, one such wall being mounted so as to limit displacement of the diaphragm toward the air-side chamber and the other wall mounted so as to limit displacement of the diaphragm toward the fluid-side chamber. Two similar dampeners may be employed, one to dampen pressure surges and the other to dampen pressure drops.