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

• US 6,581,594 B1
• Filed: 05/15/2000
• Issued: 06/24/2003
• Est. Priority Date: 05/15/2000
• Status: Expired due to Term

• Current Assignee: ResMed Pty Ltd. (ResMed Incorporated)
• Original Assignee: Resmed Limited (ResMed Incorporated)
• Inventors: Virr, Alexander, Crumblin, Geoffrey, Drew, Joanne
• Primary Examiner(s): Lewis, Aaron J.
• Application Number:
  US09/570,907
• Time in Patent Office: 1,135 Days
• Field of Search: 128/200.29, 128/201.29, 128/204.18, 128/205.11, 128/207.12, 128/207.13
• US Class Current: 128/204.18
• CPC Class Codes: A61M 16/06 Respiratory or anaesthetic masks
• CPC Class Codes: A61M 16/0633 with forehead support
• CPC Class Codes: A61M 16/0638 in the form of a pivot
• CPC Class Codes: A61M 16/0644 having the means for adjusting its position
• CPC Class Codes: A61M 16/065 in the form of a pivot
• CPC Class Codes: A61M 16/0683 Holding devices therefor
• CPC Class Codes: A61M 16/0816 Joints or connectors
• CPC Class Codes: A61M 16/0825 with ball-sockets
• CPC Class Codes: A61M 16/22 Carbon dioxide-absorbing devices ; Other means for removing carbon dioxidecartridges with absorbing substances for respiratory apparatus A62B19/00
• CPC Class Codes: A61M 2202/0085 product washed out
• CPC Class Codes: A61M 2202/0225 Carbon oxides, e.g. Carbon dioxide
• CPC Class Codes: A61M 2205/42 Reducing noise
• CPC Class Codes: A61M 2205/7536 allowing gas passage, but preventing liquid passage, e.g. liquophobic, hydrophobic, water-repellent membranes
• CPC Class Codes: A62B 18/02 Masks gas-masks for animals A62B18/06; masks for welders A61F9/06

Abstract

The present invention provides a vent assembly suitable for use with a respiratory mask of the type used in CPAP treatment. In one embodiment the vent is made of a thin air permeable membrane. Generally, the membrane is thinner than 0.5 mm. The membrane can be made of a hydrophobic material such as polytetrafluoroethylene (PTFE). The membrane can also be fabricated from expanded PTFE. The expanded PTFE membrane is mounted on a polypropylene scrim. The pores of the membrane have a reference pore size of 10 to 15 microns. In an alternative embodiment, the vent assembly includes a vent constructed from stainless steel. In another embodiment the membrane has a superficial cross-sectional area of approximately 500 mm². In another embodiment the vent assembly comprises a membrane attached to a vent frame, the vent assembly forming an insert which can be removeably attached to a mask fame.

Claims

1. 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 includes a plurality of tapered holes.

2. A respiratory mask according to claim 1, wherein each of the tapered holes includes a small end facing atmosphere.

3. A respiratory mask according to claim 1, wherein each of the tapered holes includes a small end facing an interior of the mask shell.

4. A respiratory mask according to claim 1, wherein the membrane is mounted in an insert that is selectably detachable from the mask shell.

5. A respiratory mask according to claim 1, wherein a thickness of the membrane is less than a thickness of the mask shell.

6. 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.

7. 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.

8. 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.