Abstract: Apparatus for reducing fluid-borne noise in a hydraulic system that includes a housing that defines a hollow chamber, and inlet and outlet connections for in-line connecting the apparatus in a hydraulic fluid flow system. A resilient member is disposed within the housing and effectively divides the housing chamber into a first portion adjacent to the fluid inlet and outlet for receiving hydraulic fluid, and a second portion remote from the fluid inlet and outlet for containing gas under pressure. Pressure pulsations in the hydraulic fluid are reduced and at least partially absorbed by the combined effect of resiliency of the elastic member and compressibility of the contained gas.

Abstract: Method and apparatus for suppression of fluid-borne noise in hydraulic or fluid handling systems, such as automotive power steering, power brakes, air conditioning and fuel systems wherein a multi-chamber solution to attenuate fluid-borne noise in the system is disclosed. This solution optimizes both damping, interference and wave cancellation mechanisms in a fluid system and consists of dividing an attenuator conduit hose or pipe assembly serially into tuning chambers by a restrictor or other mechanism. In some embodiments, a tuner is placed in each and every chamber. The number of chambers can vary between two and four depending on the objective of the attenuation. In order to attenuate the ripple at the pump, the tuner in the first or most upstream chamber can be removed.