Noise attenuation in a check valve unit or apparatus for producing vacuum

A check valve unit comprising:

• a housing defining an inlet port, an outlet port, and a chamber in fluid communication with the inlet port and the outlet port thereby defining a flow path from the inlet port through the chamber to the outlet port, wherein the chamber includes a first valve seat and a second valve seat;
• a sealing member disposed in the chamber and moveable from a position seated on the first valve seat to a position seated on the second valve seat;
• a sound attenuating member disposed in the flow path downstream of the chamber, disposed within the chamber, or both;
• and
• a Venturi portion having a fluid junction with the outlet port for fluid communication therewith.

A check valve unit comprising:

• a housing defining an inlet port, an outlet port, and a chamber in fluid communication with the inlet port and the outlet port thereby defining a flow path from the inlet port through the chamber to the outlet port, wherein the chamber includes a first valve seat and a second valve seat;
• a sealing member disposed in the chamber and moveable from a position seated on the first valve seat to a position seated on the second valve seat;
• a sound attenuating member disposed in the flow path downstream of the chamber, disposed within the chamber, or both;
• and
• a Venturi portion in fluid communication with the chamber, wherein a discharge section of the Venturi portion defines the outlet port of the chamber, and the sound attenuating member is disposed in the discharge section.

A check valve unit comprising:

• a housing defining an inlet port, an outlet port, and a chamber in fluid communication with the inlet port and the outlet port thereby defining a flow path from the inlet port through the chamber to the outlet port, wherein the chamber is defined between a first valve seat and a second valve seat;
• a sealing disc disposed within the chamber and moveable within the chamber between a position seated on the first valve seat to a position seated on the second valve seat, wherein the sealing member moves to an open position in response to fluid flow from the inlet port to the outlet port;
• and
• a sound attenuating member disposed in the flow path downstream of the chamber, disposed within the chamber, or both;
• wherein a first sound attenuating member is disposed in the flow path proximate the inlet port or the first sound attenuating member is disposed in the chamber and forms either the first valve seat or the second valve seat, and a second sound attenuating member is disposed in the flow path proximate the outlet port.