CA2011955A1 - Closed-circuit positive pressure breathing apparatus with pneumatically operated storage chamber - Google Patents
Closed-circuit positive pressure breathing apparatus with pneumatically operated storage chamberInfo
- Publication number
- CA2011955A1 CA2011955A1 CA002011955A CA2011955A CA2011955A1 CA 2011955 A1 CA2011955 A1 CA 2011955A1 CA 002011955 A CA002011955 A CA 002011955A CA 2011955 A CA2011955 A CA 2011955A CA 2011955 A1 CA2011955 A1 CA 2011955A1
- Authority
- CA
- Canada
- Prior art keywords
- breathing
- chamber
- conduit
- pressure
- storage chamber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
Abstract
ABSTRACT
There is disclosed a self-contained breathing apparatus of the positive pressure type wherein there is provided a pneumatic servo mechanism responsive to a pressure sensor to drive a breathing storage chamber by expansion of an oxygen containing gas from a storage tank therefor.
There is disclosed a self-contained breathing apparatus of the positive pressure type wherein there is provided a pneumatic servo mechanism responsive to a pressure sensor to drive a breathing storage chamber by expansion of an oxygen containing gas from a storage tank therefor.
Description
9~ 1 ¦¦ CLOSED-CIRCUIT POSITIVE PRESSURE B~EATIIING APPARATUS
P/4241 ,I WITH PNEUMATICALL~ OPERAT~D STORAGE C~3AMBER
il IBackground of the Invention I(l) Field oE the Invention , This invention relates to a self-contained breathing apparatus, and more particularly to a closed-circuit positive j pressure self-contained breathing apparatus for temporary use by ¦
a wearer in a noxious environment, such as is worn by a firefighter.
P/4241 ,I WITH PNEUMATICALL~ OPERAT~D STORAGE C~3AMBER
il IBackground of the Invention I(l) Field oE the Invention , This invention relates to a self-contained breathing apparatus, and more particularly to a closed-circuit positive j pressure self-contained breathing apparatus for temporary use by ¦
a wearer in a noxious environment, such as is worn by a firefighter.
(2) Description of the Prior Art Self-contained breathing apparatus (SCBA's) are worn by ¦
industrial workers, and in particular ficefighters, to provide a j safe, respirable breathing condition while the user works in a hostile environment. Currently, breathing performance and servicè life rating of such apparatus are based upon user consumption at the rate of 40 liters per minute, wherein inhalation and exhalation reach peaks instantaneous flow rates of j about 115 liters per minute. For firefighting duty, the National j IlFire Prevention Administration (NFPA) has defined new performance Istandards (for open circuit SCBA's) wherein peak instantaneous ! breathing rates exceed 200 liters per minute.
i SCB~'s are classified as open-circuit (where the user's iexhalation is dumped from the system) or closed-circuit (where I! exhalation is returned to the system for sub~equent reuse after carbon dioxide i9 removed and oxygen is added).
Although closed-circuit, self-contained breathing apparatus have existed longer than open-circuit types, there are some inherent disadvantages of closed-circuit systems which off~et the substantial weight and size advantage they offer for extended 5~
¦duration. One disadvantage lis the sluggish response of the ¦system to the user's breathing requirements, particularly at high metabolic wor~ rates. A second disadvantage is the design !difficulty encountered in trying to create a constant positive 5pressure in the facepiece (positive pressure substantially increases the degree of respiratory protection to the wearer~.
Objects of the Invention An object of the present invention is to provide an improved self-contained closed-circuit positive pressure breathing ol! apparatus of extended rating which provides an amplified response to the user's breathing effort, resulting in very low breathing resistance.
Another object of the present invention is to provide an ¦improved closed-circuit self-contained breathing apparatus which 15! is capable of maintaining a positive pressure in the facepiece, even during high inhalation flow rates, but without having substantial resistance to high exhalation flows.
Still another object of the present invention is to provide an improved closed-circuit positive pressure ~elf-contained 20breathing apparatus with breathing performance which meets or exceeds that of an open-circuit apparatus.
Yet another object of the present invention i~ to provide an improved closed-circuit self-contained positive pressure breathing apparatus.
25Summary of the Invention These and other objects of the present invention are achieved in a ~elf-contained breathing apparatus of the po3itive pressure type wherein there is provided a pneumatic servo mechani~m responsive to a pres~ure sensor to drive a breathing ¦storage chamber by expansion of an oxygen containing gas from a storage tank therefor.
~ 5~A
!~ Brief Description of the Drawing Further objects and advantages of the present invention will become apparent from the following detailed description thereof ¦Iwhen taken with the accompanying drawings wherein like numerals jldesignate like parts throughout, and wherein:
Figure 1 is a schematic flow diagram of the positive pressure self-contained breathing apparatus of the pre~ent invention; and Figure 2 is an enlarged partial cross-~ectional plan view of the pressure regulating a~embly.
Detailed De~cription of the Invention Referring now to Figure 1, there is ~chematically illustrated a self-contained breathing apparatu~ of the pre~ent invention, generally indicated as 10, mounted in a supporting carrier assembly (not ~shown) including a helmet (~) and compri~ed of a compre~sed breathing gas supply tank 12; a pneumatic servovalve assembly, generally indicated a~ 14; an inhale/exhale delivery conduit 16: a canister as~embly 18 and a breathing storage assembly 20. The breathing gas 3upply tank 12 ! (containing either air, oxygen, oxygen enriched air, or another ¦Irnixture of oxygen in combination with other breathable gases) is of a size to provide about 2 to 5 liters of air to the ~ystem, ! depending on the user'q metabolic work rate and is connected by a ¦Iconduit 22 under the control of a pressure reducer valve 24 via a il conduit 26 to the pneumatic servovalve assembly 14.
The inhale/exhale delivery conduit 16 is connected by a conduit 28 under the control of one-way valve 30 to the chemical canister assembly 18 for the removal of carbon dioxide (and po~sibly chemical addition of oxygen) therein as known to one s~illed in the art. The canister a~embly 18 is connected by a conduit 32 to the breathing storage assembly 20 defining a variable volume gaseous storage chamber 34 in fluid communication by a conduit 36 under the control of one-way valve 38 with the inhale/exhale delivery conduit 16. A conduit 40 is provided between the pneumatic servovalve assembly 14 and the 5inhale/exhale delivery conduit 16 to sense the breathing circuit pressure therein.
The canister assembly 18 contains a chemical bed (or beds) of one or more well known carbon dioxide-adsorbing material, and l possibly one or more oxygen producing chemicals. Various carbon 10dioxide-adsorbing materials are well known and readily available at relatively lnexpensive prices. The material producing oxygen could be one of several known chemicals which react with moisture and carbon dioxide to generate ox~gen, such as potassium superoxide, lithium superperborate or the like.
15The breathing storage assembly 20 is comprised of an upper wall 42 and a lower wall 44 connected by flexible bellowed-shaped side wall 46 and reinforced to withstand significant positive and negative internal pressure. Through the upper wall 42, referring particularly to Figure 2, there is slidably positioned a rod 20Imember 48 vertically disposed for reciprocal movement and mounted l by a nut S0 to the lower wall 44 of the breathing storage I assembly 20. The rod member 48 is provided with a piston 52 disposed in a cylinder member 54 mounted to an upper surface j! portion of the upper wall 42 of the breathing storage chamber 34 25land defining an upper chamber 56 and a lower chamber 58 therein.
i The cylinder member 54 is preferably mounted to the upper wall 42 of the breathing storage assembly 20 to ensure positive displacement o~ the rod member 48 mounted to the lower wall member 44 with respect to the movement of the rod member 48 and 30associated piston 52 disposed within the cylinder member 54 a~
more fully hereinafter described. The rod member 48 is provided with appropriate sealing assemblies, such as ring members 60 disposed in upper and lower walls 62 and 64 of the cylinder member 54. The piston 52 is provided with a ring seal 66 to 35prevent ~luid flow between the upper and lower chamber 56 and 58 of the ylinder member 54.
The pneumatic servovalve a~embly 14 includes a ¦cylindrically-shaped pressure sensor housing 70 defining a ~¦ chamber 72 and having a diaphragm member, generally indicated as ¦74, including a disc-~haped body portion 76 and a spindle ¦member 78 po3itioned within the chamber 72 and defining an upper chamber 80 and a lower chamber 82 with a donut-~haped flexible membrane member 84 attached between the body portion 76 and the pressure sensor housing 70. The upper portion of the pressure sensor housing 70 is provided with channels 86 to provide fluid communication between the atmosphere and the upper chamber 72 of the pressure ~ensor housing 70. A channel 88 is provided in the lower portion of the pressure ~en~or housing 70 to provide fluid communication between the lower chamber 82 and the conduit 40 as more fully hereinafter described.
The spindle member 78 is provided with an upper valve portion 92 and a lower valve portion 94 for positioning within valve seating chambers 96 and 98, respectively, formed in the upper and lower wall portions of the pressure sensor housing 70.
Diaphragm seals 100 and 102 are mounted to the upper and lower portions o the spindle member 78 and to proximate portions of the pressure sensor housing 70 to isolate the chambers 80 and 82 from the valve seating chambers 96 and 98. The upper valve seating chamber 96 is in fluid communication via an orifice 104 ¦jwith the chamber 56 of the member 54 by a conduit member 105 and 1 with the conduit 36 via a conduit 106. The lower valve seating ! chamber 98 is in fluid communication via an orifice 108 with the chamber 58 of the cylinder member 54 via a conduit member 110 and with the conduit 36 via a conduit 112.
A positive pressure of approximately 20 mm. of water in the breathing conduit 16 is transmitted to the chamber 82 via the conduit 40 so that the spindle member 78 is lifted to a neutral position with equal flow re~triction through ori~ices 104 and 108. An intermediate conduit 114 including reducing orifices 116 and 118 is provided for fluid communication between the conduit ~ .3 member 105 and the conduit member 110 and the conduit 26 to ¦provide fluid communication of the compressed air from the pressure reducer 24 to the pneumatic servovalve assembly 14.
A coil spring 118 is provided in the upper chamber of the 5pressure sensor housing 70 to bias the valve portion 94 of the spindle member 78 against the needle valve chamber 98 in order to create a positive pressure in the breathing circuit. A positive pressure of approximately 20 mm. of water in the breathing conduit 16 i9 transmitted to the chamber 82 via the conduit 40 so 10that the spindle member 78 is lifted to a neutral position with equal flow restriction through orifices 104 and 108.
In operation, the spindle member 78 acts a rod stem at each end by restricting flow through either the upper orifice 104 or ¦the lower orifice 108 thereby creating an imbalance in the 15¦pneumatic network comprised by the pneumatic resistance of the ¦orifices 104, 108, 116 and 118. Thus, the chambers 56 and 58 of the cylinder member 54 function to control the movement of the piston 52 (and thus the movement of the breathing storage chamber 20) as a result of the pressure imbalance between the 20chambers 56 and 58.
During inhalation, the pressure on the breathing circ~it in conduit 16 drops slightly below the 20 mm. static pressure, causing the pressure in the lower chamber 58 of the cylinder 54 l to increase thereby applying a net upward force against the 25¦ piston 52 of the rod member 4~ to cause the lower wall 44 to ri~e ¦and compress the breathing storage chamber 34 with sufficient ¦force to overcome what ever resistance is pre~ent between the storage chamber 34 and the helmet (~1). As the storage chamber 34 responds, pressure in the breathing circuit increase3 towards the 3020 mm. static pressuee thereby providing feed-back to the pneumatic servovalve assembly 14 thereby returning to a neutral position the spindle member 78 of the pressure sensor housing 70.
Similarly, exhalation causes an increase in breathing circuit pre~sure in conduit 16 which causes an increaqe in x~
pressure in the upper chamber 56 of the cylinder member 54 causing the breathing storage chamber 34 to expand to assist overcoming resistance in the exhalation circuitry.
In accordance with the present invention, use is made of the S energy in the pressurized breathing gas tank 12 to drive a servoassembly in response to the user's demand, energy otherwi~e unused, and without requiring substantially more gas than would be required to repleni~h oxygen or flush the rebreather system.
Following its use in pneumatically amplifying the breathing response and driving the breathing storage chamber, the breathing gas is vented into the breathing circuit conduit 36 via conduits 106 and 112. In summary, the user's breathing creates a pressure change in the breathing conduit 16 which is transmitted through the conduit 40 to the lower chamber 82 of the pneumatic servovalve assembly 14 causing the spindle member 78 to respond up or down to restrict flow through either of the restrictive orifices 104 or 108, re~pectively.
While the invention has been de~cribed in connection with an exemplary embodiment thereof, it will be understood that many modifications will be apparent to those of ordinary skill in the art, and that this application is intended to cover any adaptations of variations thereof. Therefore, it is manifestly intended that this invention be only limited by the claims and ¦the equivalents thereof.
industrial workers, and in particular ficefighters, to provide a j safe, respirable breathing condition while the user works in a hostile environment. Currently, breathing performance and servicè life rating of such apparatus are based upon user consumption at the rate of 40 liters per minute, wherein inhalation and exhalation reach peaks instantaneous flow rates of j about 115 liters per minute. For firefighting duty, the National j IlFire Prevention Administration (NFPA) has defined new performance Istandards (for open circuit SCBA's) wherein peak instantaneous ! breathing rates exceed 200 liters per minute.
i SCB~'s are classified as open-circuit (where the user's iexhalation is dumped from the system) or closed-circuit (where I! exhalation is returned to the system for sub~equent reuse after carbon dioxide i9 removed and oxygen is added).
Although closed-circuit, self-contained breathing apparatus have existed longer than open-circuit types, there are some inherent disadvantages of closed-circuit systems which off~et the substantial weight and size advantage they offer for extended 5~
¦duration. One disadvantage lis the sluggish response of the ¦system to the user's breathing requirements, particularly at high metabolic wor~ rates. A second disadvantage is the design !difficulty encountered in trying to create a constant positive 5pressure in the facepiece (positive pressure substantially increases the degree of respiratory protection to the wearer~.
Objects of the Invention An object of the present invention is to provide an improved self-contained closed-circuit positive pressure breathing ol! apparatus of extended rating which provides an amplified response to the user's breathing effort, resulting in very low breathing resistance.
Another object of the present invention is to provide an ¦improved closed-circuit self-contained breathing apparatus which 15! is capable of maintaining a positive pressure in the facepiece, even during high inhalation flow rates, but without having substantial resistance to high exhalation flows.
Still another object of the present invention is to provide an improved closed-circuit positive pressure ~elf-contained 20breathing apparatus with breathing performance which meets or exceeds that of an open-circuit apparatus.
Yet another object of the present invention i~ to provide an improved closed-circuit self-contained positive pressure breathing apparatus.
25Summary of the Invention These and other objects of the present invention are achieved in a ~elf-contained breathing apparatus of the po3itive pressure type wherein there is provided a pneumatic servo mechani~m responsive to a pres~ure sensor to drive a breathing ¦storage chamber by expansion of an oxygen containing gas from a storage tank therefor.
~ 5~A
!~ Brief Description of the Drawing Further objects and advantages of the present invention will become apparent from the following detailed description thereof ¦Iwhen taken with the accompanying drawings wherein like numerals jldesignate like parts throughout, and wherein:
Figure 1 is a schematic flow diagram of the positive pressure self-contained breathing apparatus of the pre~ent invention; and Figure 2 is an enlarged partial cross-~ectional plan view of the pressure regulating a~embly.
Detailed De~cription of the Invention Referring now to Figure 1, there is ~chematically illustrated a self-contained breathing apparatu~ of the pre~ent invention, generally indicated as 10, mounted in a supporting carrier assembly (not ~shown) including a helmet (~) and compri~ed of a compre~sed breathing gas supply tank 12; a pneumatic servovalve assembly, generally indicated a~ 14; an inhale/exhale delivery conduit 16: a canister as~embly 18 and a breathing storage assembly 20. The breathing gas 3upply tank 12 ! (containing either air, oxygen, oxygen enriched air, or another ¦Irnixture of oxygen in combination with other breathable gases) is of a size to provide about 2 to 5 liters of air to the ~ystem, ! depending on the user'q metabolic work rate and is connected by a ¦Iconduit 22 under the control of a pressure reducer valve 24 via a il conduit 26 to the pneumatic servovalve assembly 14.
The inhale/exhale delivery conduit 16 is connected by a conduit 28 under the control of one-way valve 30 to the chemical canister assembly 18 for the removal of carbon dioxide (and po~sibly chemical addition of oxygen) therein as known to one s~illed in the art. The canister a~embly 18 is connected by a conduit 32 to the breathing storage assembly 20 defining a variable volume gaseous storage chamber 34 in fluid communication by a conduit 36 under the control of one-way valve 38 with the inhale/exhale delivery conduit 16. A conduit 40 is provided between the pneumatic servovalve assembly 14 and the 5inhale/exhale delivery conduit 16 to sense the breathing circuit pressure therein.
The canister assembly 18 contains a chemical bed (or beds) of one or more well known carbon dioxide-adsorbing material, and l possibly one or more oxygen producing chemicals. Various carbon 10dioxide-adsorbing materials are well known and readily available at relatively lnexpensive prices. The material producing oxygen could be one of several known chemicals which react with moisture and carbon dioxide to generate ox~gen, such as potassium superoxide, lithium superperborate or the like.
15The breathing storage assembly 20 is comprised of an upper wall 42 and a lower wall 44 connected by flexible bellowed-shaped side wall 46 and reinforced to withstand significant positive and negative internal pressure. Through the upper wall 42, referring particularly to Figure 2, there is slidably positioned a rod 20Imember 48 vertically disposed for reciprocal movement and mounted l by a nut S0 to the lower wall 44 of the breathing storage I assembly 20. The rod member 48 is provided with a piston 52 disposed in a cylinder member 54 mounted to an upper surface j! portion of the upper wall 42 of the breathing storage chamber 34 25land defining an upper chamber 56 and a lower chamber 58 therein.
i The cylinder member 54 is preferably mounted to the upper wall 42 of the breathing storage assembly 20 to ensure positive displacement o~ the rod member 48 mounted to the lower wall member 44 with respect to the movement of the rod member 48 and 30associated piston 52 disposed within the cylinder member 54 a~
more fully hereinafter described. The rod member 48 is provided with appropriate sealing assemblies, such as ring members 60 disposed in upper and lower walls 62 and 64 of the cylinder member 54. The piston 52 is provided with a ring seal 66 to 35prevent ~luid flow between the upper and lower chamber 56 and 58 of the ylinder member 54.
The pneumatic servovalve a~embly 14 includes a ¦cylindrically-shaped pressure sensor housing 70 defining a ~¦ chamber 72 and having a diaphragm member, generally indicated as ¦74, including a disc-~haped body portion 76 and a spindle ¦member 78 po3itioned within the chamber 72 and defining an upper chamber 80 and a lower chamber 82 with a donut-~haped flexible membrane member 84 attached between the body portion 76 and the pressure sensor housing 70. The upper portion of the pressure sensor housing 70 is provided with channels 86 to provide fluid communication between the atmosphere and the upper chamber 72 of the pressure ~ensor housing 70. A channel 88 is provided in the lower portion of the pressure ~en~or housing 70 to provide fluid communication between the lower chamber 82 and the conduit 40 as more fully hereinafter described.
The spindle member 78 is provided with an upper valve portion 92 and a lower valve portion 94 for positioning within valve seating chambers 96 and 98, respectively, formed in the upper and lower wall portions of the pressure sensor housing 70.
Diaphragm seals 100 and 102 are mounted to the upper and lower portions o the spindle member 78 and to proximate portions of the pressure sensor housing 70 to isolate the chambers 80 and 82 from the valve seating chambers 96 and 98. The upper valve seating chamber 96 is in fluid communication via an orifice 104 ¦jwith the chamber 56 of the member 54 by a conduit member 105 and 1 with the conduit 36 via a conduit 106. The lower valve seating ! chamber 98 is in fluid communication via an orifice 108 with the chamber 58 of the cylinder member 54 via a conduit member 110 and with the conduit 36 via a conduit 112.
A positive pressure of approximately 20 mm. of water in the breathing conduit 16 is transmitted to the chamber 82 via the conduit 40 so that the spindle member 78 is lifted to a neutral position with equal flow re~triction through ori~ices 104 and 108. An intermediate conduit 114 including reducing orifices 116 and 118 is provided for fluid communication between the conduit ~ .3 member 105 and the conduit member 110 and the conduit 26 to ¦provide fluid communication of the compressed air from the pressure reducer 24 to the pneumatic servovalve assembly 14.
A coil spring 118 is provided in the upper chamber of the 5pressure sensor housing 70 to bias the valve portion 94 of the spindle member 78 against the needle valve chamber 98 in order to create a positive pressure in the breathing circuit. A positive pressure of approximately 20 mm. of water in the breathing conduit 16 i9 transmitted to the chamber 82 via the conduit 40 so 10that the spindle member 78 is lifted to a neutral position with equal flow restriction through orifices 104 and 108.
In operation, the spindle member 78 acts a rod stem at each end by restricting flow through either the upper orifice 104 or ¦the lower orifice 108 thereby creating an imbalance in the 15¦pneumatic network comprised by the pneumatic resistance of the ¦orifices 104, 108, 116 and 118. Thus, the chambers 56 and 58 of the cylinder member 54 function to control the movement of the piston 52 (and thus the movement of the breathing storage chamber 20) as a result of the pressure imbalance between the 20chambers 56 and 58.
During inhalation, the pressure on the breathing circ~it in conduit 16 drops slightly below the 20 mm. static pressure, causing the pressure in the lower chamber 58 of the cylinder 54 l to increase thereby applying a net upward force against the 25¦ piston 52 of the rod member 4~ to cause the lower wall 44 to ri~e ¦and compress the breathing storage chamber 34 with sufficient ¦force to overcome what ever resistance is pre~ent between the storage chamber 34 and the helmet (~1). As the storage chamber 34 responds, pressure in the breathing circuit increase3 towards the 3020 mm. static pressuee thereby providing feed-back to the pneumatic servovalve assembly 14 thereby returning to a neutral position the spindle member 78 of the pressure sensor housing 70.
Similarly, exhalation causes an increase in breathing circuit pre~sure in conduit 16 which causes an increaqe in x~
pressure in the upper chamber 56 of the cylinder member 54 causing the breathing storage chamber 34 to expand to assist overcoming resistance in the exhalation circuitry.
In accordance with the present invention, use is made of the S energy in the pressurized breathing gas tank 12 to drive a servoassembly in response to the user's demand, energy otherwi~e unused, and without requiring substantially more gas than would be required to repleni~h oxygen or flush the rebreather system.
Following its use in pneumatically amplifying the breathing response and driving the breathing storage chamber, the breathing gas is vented into the breathing circuit conduit 36 via conduits 106 and 112. In summary, the user's breathing creates a pressure change in the breathing conduit 16 which is transmitted through the conduit 40 to the lower chamber 82 of the pneumatic servovalve assembly 14 causing the spindle member 78 to respond up or down to restrict flow through either of the restrictive orifices 104 or 108, re~pectively.
While the invention has been de~cribed in connection with an exemplary embodiment thereof, it will be understood that many modifications will be apparent to those of ordinary skill in the art, and that this application is intended to cover any adaptations of variations thereof. Therefore, it is manifestly intended that this invention be only limited by the claims and ¦the equivalents thereof.
Claims (9)
1. A rebreathing apparatus for use by a wearer having a respiratory system, which comprises:
an inhale/exhale breathing conduit;
an exhaust gas scrubber means for removing carbon dioxide from an exhaled gaseous stream and having an inlet connected to said inhale/exhale breathing conduit;
a breathing storage chamber including means for varying volume of said breathing storage chamber;
a conduit means for providing fluid flow between said exhaust gas scrubber means and said breathing storage chamber;
a conduit means for providing fluid flow between said breathing storage chamber and said inhale/exhale breathing conduit;
a breathing gas supply tank;
a regulator valve having an inlet and an outlet;
a conduit means for providing fluid flow between said breathing gas supply tank and said inlet of said regulator valve;
a pressure sensor means in fluid flow communication with said outlet of said regulator valve, said pressure sensor means having a piston defining a chamber in fluid communication with ambient pressure and a chamber in fluid communication with said inhale/exhale breathing conduit, said pressure sensor means having valve chambers in alternating fluid flow communication with said means for varying volume of said breathing storage chamber whereby pressure of inhalation/exhalation drives said means for varying pressure of said breathing storage chamber to increase/decrease pressure, respectively, of said breathing storage chamber.
an inhale/exhale breathing conduit;
an exhaust gas scrubber means for removing carbon dioxide from an exhaled gaseous stream and having an inlet connected to said inhale/exhale breathing conduit;
a breathing storage chamber including means for varying volume of said breathing storage chamber;
a conduit means for providing fluid flow between said exhaust gas scrubber means and said breathing storage chamber;
a conduit means for providing fluid flow between said breathing storage chamber and said inhale/exhale breathing conduit;
a breathing gas supply tank;
a regulator valve having an inlet and an outlet;
a conduit means for providing fluid flow between said breathing gas supply tank and said inlet of said regulator valve;
a pressure sensor means in fluid flow communication with said outlet of said regulator valve, said pressure sensor means having a piston defining a chamber in fluid communication with ambient pressure and a chamber in fluid communication with said inhale/exhale breathing conduit, said pressure sensor means having valve chambers in alternating fluid flow communication with said means for varying volume of said breathing storage chamber whereby pressure of inhalation/exhalation drives said means for varying pressure of said breathing storage chamber to increase/decrease pressure, respectively, of said breathing storage chamber.
2. The rebreathing apparatus as defined by Claim 1 wherein said breathing storage chamber includes a top wall, bottom wall and bellowed side walls, said bottom wall moves relative to said top wall for varying pressure of said breathing storage chamber.
3. The rebreathing apparatus as defined by Claim 2 wherein a breathing gas cylinder and piston are associated with said breathing storage chamber, said piston including a rod member connected to said bottom wall for moving said bottom wall relative to said top wall.
4. The rebreathing apparatus as defined by Claim 2 or 3 wherein said piston defines an upper chamber and a lower chamber within said breathing gas cylinder, one of said chambers being in fluid flow communication with one of said valve chambers of said pressure regulator valve associated with said chamber in fluid communication with ambient pressure and another of said chambers being in fluid flow communication with one of said valve chambers of said pressure regulator valve associated with said chamber in fluid communication with said inhale/exhale breathing conduit.
5. the rebreathing apparatus as defined by Claim 4 wherein said one of said chambers of said breathing gas chamber is said upper chamber thereof said another of said chambers of said air chamber is said lower chamber thereof.
6. The rebreathing apparatus as defined by Claim 5 and further including a first conduit member for providing fluid communication between said upper chamber of said breathing gas cylinder and said valve chamber of said pressure sensor associated with said chamber in fluid communication with ambient pressure and a second conduit member for providing fluid communication between said lower chamber of said breathing gas cylinder and said valve chamber of said pressure sensor associated with said chamber in fluid communication with said inhale/exhale breathing conduit and further including a third conduit member in fluid flow with said conduit means of said breathing gas supply tank, said third conduit including orifice members between said conduit means and said first and second conduit members.
7. The rebreathing apparatus as defined by Claim 4 wherein said valve chambers of said pressure sensor means are sealed by a flexible membrane with respect to said associated chambers of said pressure sensor means.
8. The rebreathing apparatus as defined by Claim 6 and further including a spring member for biasing said piston of said pressure sensor means to create positive pressure in said breathing circuit.
9. The rebreathing apparatus as defined by Claim 4 when said spring member is biased to a positive pressure of about 20 mm. of water.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002011955A CA2011955A1 (en) | 1990-03-12 | 1990-03-12 | Closed-circuit positive pressure breathing apparatus with pneumatically operated storage chamber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002011955A CA2011955A1 (en) | 1990-03-12 | 1990-03-12 | Closed-circuit positive pressure breathing apparatus with pneumatically operated storage chamber |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2011955A1 true CA2011955A1 (en) | 1991-09-12 |
Family
ID=4144506
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002011955A Abandoned CA2011955A1 (en) | 1990-03-12 | 1990-03-12 | Closed-circuit positive pressure breathing apparatus with pneumatically operated storage chamber |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2011955A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111420313A (en) * | 2020-05-15 | 2020-07-17 | 上海孚邦实业有限公司 | Closed circuit type respirator |
| CN117419945A (en) * | 2023-12-19 | 2024-01-19 | 四川烈火胜服科技有限公司 | Closed circulation type respirator performance detection device |
-
1990
- 1990-03-12 CA CA002011955A patent/CA2011955A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111420313A (en) * | 2020-05-15 | 2020-07-17 | 上海孚邦实业有限公司 | Closed circuit type respirator |
| CN117419945A (en) * | 2023-12-19 | 2024-01-19 | 四川烈火胜服科技有限公司 | Closed circulation type respirator performance detection device |
| CN117419945B (en) * | 2023-12-19 | 2024-03-12 | 四川烈火胜服科技有限公司 | Closed circulation type respirator performance detection device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued | ||
| FZDE | Discontinued |
Effective date: 19940913 |