Closed circuit type respirator

• US 4,633,868 A
• Filed: 05/22/1985
• Issued: 01/06/1987
• Est. Priority Date: 06/04/1984
• Status: Expired due to Fees

• Current Assignee: ITOH Seiki Kabushiki Kaisha
• Original Assignee: ITOH Seiki Kabushiki Kaisha
• Inventors: Itoh, deceased, Kazu, Itoh, legal representative, Akira
• Primary Examiner(s): Recla, Henry J.
• Application Number:
  US06/736,718
• Time in Patent Office: 594 Days
• Field of Search: 128/204.26, 128/204.28, 128/205.12, 128/204.22, 128/205.24
• US Class Current: 128/204.26
• CPC Class Codes: A62B 7/04 and lung-controlled oxygen or air valves
• CPC Class Codes: A62B 7/10 with filter elements

Abstract

A closed-circuit type respirator includes an oxygen enriching valve provided in an exhalation system of the respirator, preferably at the lower front end of a respirator mask. This oxygen enriching valve comprises a housing having a passage communicating to the exhalation system and a passage communicating to the atmosphere, a first valve which is provided in the passage communicating to the exhalation system and opens only when pressurized for exhalation and a second valve which is provided in the passage communicating to the atmosphere and is opened for a desired period of time by an external force such as manual operation so that the space inside the housing communicates with the atmosphere. By manually or otherwise opening the second valve of the oxygen enriching valve whenever necessary and making a few deep breathings, the exhaled air is discharged in the atmosphere, reducing the pressure in the circulation system and effecting automatic supply of oxygen, whereby insufficiency of oxygen supply can be avoided.

Claims

1. In a closed-circuit type respirator including a face mask, an inhalation conduit communicating with said face mask, and exhalation conduit communicating with said face mask, a first check valve provided in said inhalation conduit, a second check valve provided in said exhalation conduit;

said face mask, exhalation conduit and second check valve constituting at least a part of an exhalation system which is a section of the respirator where exhaled air passes, and an oxygen demand system connected to said inhalation conduit and supplying oxygen automatically when the pressure in the respirator is reduced to a predetermined level characterized in that said respirator comprises an oxygen enriching valve provided in said exhalation system, said oxygen enriching valve including a housing opening to said exhalation system on one side and to atmosphere on the other side, first valve means provided within said housing on the side opening to said exhalation system and being capable of opening only when pressurized by exhaled air to let the air from said exhalation system into said housing, second valve means provided within said housing on the side opening to the atmosphere and being capable of opening for a predetermined period of time by applying an external force for communicating the inside of said housing to atmosphere, the air in said exhalation system being let out through said first and second valve means when said second valve means is opened and the pressure in the respirator thereby being reduced to the predetermined level at which oxygen is automatically supplied.

2. A closed-type respirator as defined in claim 1 wherein said oxygen enriching valve is provided at the lower front end of said face mask.

3. A closed-type respirator as defined in claim 1 wherein said first valve means comprises a check valve exposed to said exhalation system and closing the side of said housing opening to said exhalation system when said check valve is not pressurized by exhaled air and a valve seat provided on said housing.

4. A closed-circuit type respirator as defined in claim 1 wherein said second valve means is manually operated.

5. A closed-circuit type respirator as defined in claim 4 wherein said second valve means comprises a disk-like manual valve exposed to atmosphere, a push button fixed to said manual valve, a valve seat for said manual valve provided on said housing and spring means interposed between said push button and said disk-like member.