Demand regulator protective bellows

1. A self contained breathing apparatus (SCBA) having a demand regulator comprising:

a source of breathing gas;

a mask with a lens;

a demand regulator connected to said mask and said source of breathing gas;

a flexible member in said demand regulator that moves in response to pressure differentials;

a valve for introducing breathing gas through said regulator to said mask connected for movement in response to movement of said flexible member; and,

an expanding and contracting member fluidically connected to said flexible member which can move in an expanding or contracting manner upon movement of said flexible member.

2. The SCBA as claimed in claim 1 further comprising:

said flexible member is at least in part formed of an elastomer.

3. The SCBA as claimed in claim 2 further comprising:

said expanding and contracting member has one side exposed to the outside of said flexible member and the other side exposed to the ambient with a space between said flexible member and said expanding and contracting member.

4. The SCBA as claimed in claim 3 further comprising:

said expanding and contracting member has a cross-section formed of at least one concave and convex portion.

5. The SCBA as claimed in claim 3 further comprising:

said expanding and contracting member has a bellows cross-sectional configuration.

6. The SCBA as claimed in claim 3 further comprising:

said flexible member is at least in part a diaphragm; and,

said expanding and contracting member has a mushroom shape.

7. The SCBA as claimed in claim 3 further comprising:

said expanding and contracting member is formed of a balloon shape.

8. The SCBA as claimed in claim 3 further comprising:

a membrane forming said expanding and contracting member having one side exposed to ambient and the other side to said flexible member with a space therebetween for a fluid.

9. A demand breathing gas regulator comprising:

a regulator body for fluid connection to a mask and a source of breathing gas;

a flexible member that is at least in part formed of a diaphragm and that is operably connected to a breathing gas demand valve supported by said regulator body, said flexible member having one side fluidically connected to an inside of the mask with the other side exposed to a fluid chamber;

an expanding and contracting member that is an elastomeric member having a convex or concave portion exposed to said fluid chamber and that is connected to said fluid chamber for movement in response to movement of said flexible member as sensed through said fluid chamber;

and said expanding and contracting member being formed with a rounded portion as a balloon or mushroom shaped configuration.

10. The demand breathing gas regulator as claimed in claim 9 further comprising:

a pilot valve of said regulator that moves in response to pressure differentials on said flexible member; and,

a second valve which valves breathing gas through said regulator in response to said pilot valve.

11. The demand breathing gas regulator as claimed in claim 10 further comprising:

said expanding and contracting member has a compound curved portion formed with at least one convex and one concave portion.

12. A contaminant shielding system for a breathing gas demand regulator comprising:

a demand breathing gas regulator adapted for connection to a source of breathing gas and a user's mask;

a flexible member fluidically connected on one side to said source of breathing gas and on the other side to a chamber having a fluid therein; and,

an expanding and contracting member substantially sealing the fluid within the chamber and in fluid communication with the fluid in said chamber which expands and contracts in response to movement of said flexible member.

13. The contaminant shielding system for a breathing gas demand regulator as claimed in claim 12 wherein:

said expanding and contracting member is formed of an elastomer.

14. The contaminant shielding system for a breathing gas demand regulator as claimed in claim 13 wherein:

said flexible member is at least in part a diaphragm.

15. The contaminant shielding system for a breathing gas demand regulator as claimed in claim 14 wherein:

said expanding and contracting member has at least either one convex or one concave portion exposed to the fluid in said chamber.

16. The contaminant shielding system for a breathing gas demand regulator as claimed in claim 15 further comprising:

said system is connected with a self contained breathing apparatus (SCBA).

17. A method for providing regulated breathing gas through a demand regulator comprising:

providing a source of breathing gas;

regulating said breathing gas to an intermediate pressure by a first stage regulator;

conducting said intermediate pressure gas to a demand regulator;

regulating said intermediate pressure by the demand regulator having a flexible member exposed on one side to a chamber having a fluid therein and on the other side to breathing gas;

providing an expanding and contracting sealing member exposed to the fluid in said chamber; and,

allowing said expanding and contracting sealing member to expand and contract in response to movement of said flexible member.

18. The method as claimed in claim 17 further comprising:

said flexible member is formed at least in part from an elastomer.

19. The method as claimed in claim 17 further comprising:

said intermediate pressure is regulated by a valve mechanism connected to said flexible member.

20. The method as claimed in claim 19 further comprising:

providing an expanding and contracting member having a convex or concave side exposed to the fluid in said chamber.

21. A regulator assembly for use in a breathing apparatus, the regulator assembly comprising a valve assembly comprising an inlet for connection to a source of breathing gas, an outlet for connection to a facepiece to provide breathing gas to a user and an actuator for controlling flow of breathing gas between the inlet and the outlet, a flexible elastomeric diaphragm in operative connection with the actuator, the diaphragm being exposed to ambient pressure on a first side thereof and a positive pressure within the facepiece on a second side thereof and an impermeable and flexible member that substantially seals the first side of the diaphragm from toxic substances in the ambient atmosphere while allowing the first side of the diaphragm to experience ambient pressure such that the flexible member moves with the diaphragm during respiration of the user.

22. The regulator assembly of claim 21 , wherein the flexible member permits sufficient movement of the diaphragm to maintain operability of the regulator assembly.

23. A regulator for a breathing apparatus comprising a diaphragm comprising an inside surface and an outside surface, the inside surface exposed to breathing gas, the outside surface exposed to a chamber, an opening placing an interior of the chamber in communication with ambient pressure, the diaphragm being isolated from the opening by a flexible member such that ambient pressure is transmitted through the flexible member to the diaphragm while contaminants in ambient air are not readily transmitted through the flexible member to the diaphragm.

24. The regulator of claim 23 , wherein the flexible member comprises a bellows configuration.

25. The regulator of claim 24 , wherein the bellows configuration is adapted for expansion, contraction, movement or stretching to accommodate fluid movement.

26. The regulator of claim 24 , wherein the bellows comprises a stretchable device.

27. The regulator of claim 23 , wherein the flexible member comprises a mushroom configuration.

28. The regulator of claim 23 , wherein the flexible member comprises a balloon type expansion and contraction member.

29. The regulator of claim 23 , wherein the flexible member comprises a secondary diaphragm.

30. The regulator of claim 23 , wherein the flexible member is adapted to move in tandem with the diaphragm.

31. The regulator of claim 23 , wherein the flexible member comprises a flange that seats on a portion of the regulator.

32. The regulator of claim 31 , wherein the portion of the regulator comprises an undercut that receives the flange.

33. The regulator of claim 23 , wherein at least a portion of the flexible member is positioned in the chamber.

34. The regulator of claim 33 , wherein a majority of the flexible member is positioned in the chamber.

35. The regulator of claim 34 , wherein the entire flexible member is position within the regulator.