Noise reduction unit for vacuum suction drains

A noise reduction unit for inserting in a vacuum suction drain, wherein the noise reduction unit is adapted to be flown through by a material to be conveyed through the vacuum suction drain extending between a suction point and a collection point, the noise reduction unit comprising:

• an inlet section with a first diameter, the inlet section configured to be connected to an inlet section of the vacuum suction drain;
• a middle section with a second diameter;
• and
• an outlet section with a third diameter, the outlet section configured to be connected to an outlet section of the vacuum suction drain;
• wherein the middle section is arranged between the inlet section and the outlet section in a longitudinal direction of the noise reduction unit;
• wherein the middle section is adapted to affect a flow velocity reduction of the material to be conveyed from the inlet section to the outlet section by causing turbulences therein, thereby reducing an effective cross-section of the vacuum section drain;
• wherein the second diameter differs from both the first diameter and the third diameter;
• wherein the second diameter is smaller than the first diameter;
• wherein, in the longitudinal direction of the noise reduction unit, the middle section narrows towards a central axis of the noise reduction unit from the first diameter to the second diameter and subsequently broadens from the second diameter to the third diameter such that the middle section is adapted to the outlet section.