Noise attenuation in a Venturi device and/or check valves

A Venturi device for producing vacuum comprising:

• a housing defining a motive port, a suction port, a discharge port, a first flow passage between the motive port and the discharge port comprising a first tapering portion aligned end to end with a second tapering portion and spaced a distance apart from the second tapering port to define a fluid junction in fluid communication with the suction port, and a discharge section downstream of the second tapering portion, wherein the first tapering portion converges toward the fluid junction and the second tapering portion diverges from the fluid junction, and the housing further defining a second flow passage comprising an inlet port, a first port in fluid communication with the suction port, and a second port in fluid communication with the discharge section of the first flow passage, wherein the housing has an exterior surface;
• a first check valve incorporated into the housing and positioned to control fluid flow through the suction port;
• a second check valve incorporated into the housing and positioned to control fluid flow between the second port and the discharge section;
• a first sound attenuating member disposed downstream of the first check valve within the second tapering portion;
• and
• a sound attenuating material seated against the exterior surface of the housing, thereby encapsulating the first check valve and all or a portion of the housing defining the first flow passage and the second flow passage.