Housing for a flow sensor ventilator including a tubulator and a membrane

A flow meter comprising:

• a housing;
• a tube provided at least partially within the housing, wherein the tube comprises an inlet portion having a first inner diameter, an outlet portion comprises a second inner diameter, and an intermediate portion comprises a third inner diameter;
• wherein the third inner diameter is smaller than both the first inner diameter and the second inner diameter;
• a first pressure measuring point located in the inlet portion and about the intermediate portion;
• a second pressure measuring point located in the intermediate portion;
• and
• a turbulator provided at the inlet portion of the tube, wherein the turbulator comprises a hollow cylinder having a cylinder wall and a plate extending across the cylinder, wherein the cylinder wall and plate comprise a plurality of apertures therethrough, wherein the turbulator is adapted to create a turbulent gas flow in the inlet portion
• wherein the turbulator is arranged in the inlet portion such that the plate is arranged at a distance from an inlet opening of the tube, wherein an annular space is provided between the cylinder wall and the inner wall of the inlet portion;
• a flexible membrane disposed about the outlet portion of the tube;
• a flow exhaust channel in fluid communication with the outlet portion of the tube, the exhaust channel at least partly surrounding the tube;
• and
• a pilot pressure chamber arranged adjacent to the outlet portion of the tube and adjacent to the exhaust channel;
• wherein the flexible membrane is arranged between the pilot pressure chamber on one side and the outlet portion and the exhaust channel on the other side, wherein the membrane is arranged such that an air flow resistance of a gas flow from the outlet end and into the exhaust channel is the lowest in a portion of the outlet end the most distant from the second pressure measurement point.