Abstract:
A self-contained breathing apparatus or a respirator can be equipped with a sensor of ambient airborne conditions. A display unit can be carried by a face mask for the apparatus or respirator. Responsive to output signals from the sensor, the display unit can present an air quality indicator, or a breathability indicator to a user of the apparatus or respirator.

Description:
FIELD 
     The invention pertains to self-contained breathing apparatus (SCBA), or respirators. More particularly, the invention pertains to such units which include an air quality, or gas sensor or sensors to provide feedback to a user as to when the SCBA, or respirator should be used. 
     BACKGROUND 
     Various types of self-contained breathing apparatus are available for use by first responders such as fire fighters. Alternately respirators are available for use where an air filter will suffice. One such configuration is illustrated in U.S. Pat. No. 5,572,991 entitled, Air Flush System for a Firefighter&#39;s Garment which issued Nov. 12, 1996. Other configurations are illustrated in U.S. Pat. No. 6,328,031 entitled, Firefighting Hood and Face Mask Assembly which issued Dec. 11, 2001 and is incorporated herein by reference. 
     In all such situations, there is an on-going question as to whether the SCBA or the respirator continue to be needed. Unfortunately, at times, first responders will assume that the ambient air is safe to breathe, in the absence of any other information, and expose themselves to hostile or contaminated air. 
     There is thus a continuing need to provide such users with timely and accurate information as to local air quality. Preferably, such information can be provided using the type of equipment that they are used to and in a way which does not require them to make efforts to obtain such feedback. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of an apparatus which embodies the invention; 
         FIG. 2  is an enlarged partial view of a portion of the apparatus of  FIG. 1 ; and 
         FIG. 3  is a block diagram illustrating additional details of the apparatus of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     While embodiments of this invention can take many different forms, specific embodiments thereof are shown in the drawings and will be described herein in detail with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention, as well as the best mode of practicing same, and is not intended to limit the invention to the specific embodiment illustrated. 
     In one aspect of the invention, either a SCBA or a respirator can be equipped with an air quality sensor and a heads-up display. The sensor or sensors can be located or carried anywhere on or in the vicinity of the SCBA or the respirator. 
     An air quality message can be visually presented for a user on a face mask which is part of the SCBA or the regulator. The message can be continually or intermittently presented to the user. 
     In another aspect of the invention, an air quality sensor can be carried on the face mask adjacent to the transparent face plate through which the user views the local region. Atmospheric quality evaluation circuitry can also be carried on the face mask, adjacent to the sensor. 
     A substantially transparent display can be located on the face plate. Alternately, a liquid crystal display or the like can be positioned on the face plate, visible to the user, but located so as not to interfere with over-all vision of the local region. Other types of visual output devices, such as light emitting diodes come within the spirit and scope of the invention and can also be used. Audible output devices can also be provided. 
     A variety of sensor types come within the spirit and scope of the invention. These include oxygen, carbon monoxide, or, carbon dioxide sensors, sensors of other dangerous or explosive gases, all without limitation. Devices which sense multiple different gases can also be used. Additionally, a temperature sensor can be provided in combination with the gas sensor(s) to provide feedback as to ambient temperatures. 
       FIG. 1  illustrates an apparatus  10  in accordance with the invention. The apparatus  10  includes a firefighter&#39;s protective outfit which includes a coat  12  and pants  12   a . An illustrated SCBA includes a tank  14  of compressed breathable air coupled to a facemask  18  via a hose  20  and a regulator/valve  22 . Hose  20  in combination with the regulator/valve  22  can convey breathable air to the user. 
     Face mask  18  includes a transparent plastic face plate  30 . As best seen in  FIG. 2 , mask  18  also carries a sensor of airborne gas or particulate matter  32  coupled to a heads-up type display  36  via conductors  38 , shown in phantom in  FIG. 1 ,  2 . 
     As noted above, the sensor  32  can be selected from a variety of gas sensors, or sensors of airborne particulate matter such as smoke, and may be readily replaceable depending on the environment into which the first responder or fire fighter is operating. The exact details of such sensors are not limitations of the invention. 
     As illustrated in  FIG. 2 , air quality indicia  40  can be presented on the display  36 . Representative indicia  40  could alphanumeric text that could display a message, such as AIR OK, or, DANGER, USE SCBA. Alternately, instead of a message, a symbol of acceptable quality, or a different symbol of danger can be displayed, all without limitation. Multiple messages or symbols, or both can be displayed as useful or appropriate. 
       FIG. 3  is a block diagram which illustrates sensor  32  coupled to control and evaluation circuits  42 . The circuits  42  determine the acceptability of the ambient air outside of the face mask  18 . As noted above, sensor  32  could be selected from a plurality of sensors  32   a  and could be field replaceable. Such replaceable units could couple their identity to circuits  42  for purposes of carrying out the appropriate quality evaluation. A temperature sensor could also be carried in the vicinity of sensor  32  and coupled to the control circuits  42  so as to provide feedback on the display as to local temperatures. 
     Output signals from circuits  42  can be coupled to the visual display  36  via the conductors  38 . Power can be supplied by a replaceable battery  46 . An audible output device, such as a beeper or horn could also be carried by the mask  18  and coupled to the control circuits  42  to provide an audible warning to a user. 
     From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.