Abstract: A pulsation dampener and acoustic attenuator for hydraulic systems is designed to be inserted into a liquid flow line. The dampener is a flow-through device with a pressurized bladder restrained within a perforated sleeve. The arrangement of inlet/outlet ports, the bladder, and the screen provides means for dampening flow pulsations in the supply system to effect a more uniform flow and to attenuate acoustic noises reverberating within the system. The dampener provides for self-cleaning due to the flow of the liquid and is thus suitable for sanitary applications. Further, the bladder may be readily removed through one end of the dampener without otherwise removing the dampener from the pipeline in order to examine or replace the bladder.