Abstract: A flexible diaphragm is disposed in a housing between a working fluid and a gas-charged chamber to damp pulsations in the working fluid. The diaphragm has a flat base that, when fully distended by pressure in the gas chamber, lies against a flat, perforated circular metal sheet. The perforated metal sheet is closely spaced from a planar backing surface that prevents the sheet from permanently deforming under the force exerted by the pressurized diaphragm. An annular channel formed in the backing surface places the working fluid in contact with the perforated metal sheet. Pressure in the working fluid displaces the diaphragm away from the perforated metal sheet. A flat retaining wall in the gas chamber limits the travel of the diaphragm away from the metal sheet. Pressure pulsations in the working fluid move the diaphragm back and forth between the retaining walls.