Respiratory mask having gas washout vent and gas washout vent for respiratory mask

A respiratory mask comprising:

• a mask shell that can be fitted over a user's nose;
• a cushion positioned in proximity to an edge portion of the mask shell to aid in fitting the mask shell to a user's face;
• a breathable gas inlet that can conduct gas through the mask shell to a breathing cavity formed between the mask shell and a user's face when the mask is in use;
• and
• a gas washout vent made from a thin air permeable membrane formed, constructed and arranged to allow gas to exit from the breathing cavity,
• wherein the membrane is formed in an opening of the respiratory mask, and a cross piece is formed across the opening.

A respiratory mask comprising:

• a mask shell fittable over a user's nose;
• a cushion positioned in proximity to an edge portion of the mask shell to aid in fitting the mask shell to a user's face;
• a breathable gas inlet to conduct gas through the mask shell to a breathing cavity formed between the mask shell and the user's face when the mask is in use;
• and
• a gas washout vent including an air permeable member to allow gas to exit from the breathing cavity, wherein
• the member comprises a stainless steel sheet having a thickness of less than about 0.5 mm, the stainless steel sheet includes a plurality of holes, an area of the holes is substantially 5% of a total superficial surface area of the stainless steel sheet, a diameter of each of the holes is less than 0.2 mm, a total open area of the holes is approximately 1-25% of the superficial surface area of the stainless steel sheet, and an area of the stainless steel sheet is about 322 mm2.

A respiratory mask comprising:

• a mask shell fittable over a user's nose;
• a cushion positioned in proximity to an edge portion of the mask shell to aid in fitting the mask shell to a user's face;
• a breathable gas inlet to conduct gas through the mask shell to a breathing cavity formed between the mask shell and the user's face when the mask is in use;
• and
• a gas washout vent including an air permeable member to allow gas to exit from the breathing cavity, wherein
• the member comprises an expanded polytetrafluoroethylene sheet having a thickness of about 0.05 mm, the sheet includes a plurality of pores in the range of 10-15 microns, an area of the sheet is approximately 480 mm2, a bubble point of the sheet is at least 0.02 bar, and an airflow capacity of the sheet is about 0.37 LPM/cm2.