Portable gas powered positive pressure breathing apparatus and method
View Patent ↗A portable positive pressure breathing apparatus includes a demand valve with a supply inlet port adapted to be connected to a pressurized source of oxygen and an outlet port adapted to be connected to the inlet of a patient's breathing appliance. The demand valve further includes a reference chamber and a valve assembly responsive to the reference chamber/appliance inlet pressure differential for connecting/disconnecting the inlet port to and from the outlet port. At least one manually adjustable back pressure regulator is connected to the pressure source and the reference chamber for setting the pressure in the reference chamber (and inlet to the breathing appliance) at a selected level above atmospheric pressure.
1. A demand valve comprising:
a gas inlet port;
a gas outlet port;
a gas powered control valve comprising a reference pressure chamber and a second chamber in uninterrupted fluid connection with the gas outlet port, wherein the control valve is responsive to a difference between a substantially constant reference pressure in the reference pressure chamber and a pressure in the gas outlet port to provide at least an inhalation mode and an exhalation mode; and
a main valve in uninterrupted fluid connection with the gas inlet port and the gas outlet port, wherein in the inhalation mode, the gas inlet port and the gas outlet port are in fluid connection through the main valve, and in the exhalation mode, the gas inlet port and the gas outlet port are substantially not in fluid connection through the main valve.
2. The demand valve of claim 1 , wherein the main valve is gas powered.
3. The demand valve of claim 2 , wherein the main valve comprises a diaphragm valve in fluid connection with the control valve assembly.
4. The demand valve of claim 1 , wherein the reference pressure is a pressure of a reference pressure chamber.
5. The demand valve of claim 4 , wherein the control valve assembly further comprises a sensing diaphragm adjacent to the reference pressure chamber.
6. The demand valve of claim 4 , wherein a first adjustable back pressure regulator determines, at least in part, the reference pressure.
7. The demand valve of claim 6 , wherein the first adjustable back pressure regulator comprises a poppet valve.
8. The demand valve of claim 6 , wherein the first adjustable back pressure regulator is in fluid connection with the gas inlet port.
9. The demand valve of claim 6 , further comprising a second adjustable back pressure regulator and a selector valve in fluid connection with the first adjustable back pressure regulator and the second adjustable back pressure regulator, wherein the second adjustable back pressure regulator determines, at least in part, the reference pressure.
10. The demand valve of claim 6 , further comprising a preadjusted back pressure regulator and a selector valve in fluid connection with the first adjustable back pressure regulator and the preadjusted back pressure regulator, wherein the preadjusted back pressure regulator determines, at least in part, the reference pressure.
11. The demand valve of claim 1 , wherein the control valve assembly comprises a pilot valve.
12. The demand valve of claim 1 , further comprising a nebulizer valve in fluid connection with the gas inlet port and a nebulizer valve outlet, wherein in the inhalation mode, the gas inlet port and the nebulizer valve outlet are in fluid connection through the nebulizer valve, and in the exhalation mode, the gas inlet port and the nebulizer valve outlet are substantially not in fluid connection through the nebulizer valve.
13. The demand valve of claim 12 , wherein the nebulizer valve comprises a diaphragm valve in fluid connection with the control valve assembly.
14. A demand regulator comprising:
the demand valve of claim 1 ;
an adjustable backpressure regulator, wherein the adjustable back pressure regulator determines, at least in part, the reference pressure; and
a pressure gauge in fluid connection with the outlet port of the demand valve.
15. A demand regulator comprising:
a gas inlet port dimensioned and configured for fluid connection to a pressurized source of breathable gas;
a gas outlet port dimensioned and configured for fluid connection to a patient breathing appliance;
a demand valve comprising:
a gas powered control valve assembly comprising:
a diaphragm valve comprising a sensing diaphragm, a reference pressure chamber adjacent to a first surface of the sensing diaphragm, and a second chamber adjacent to a second surface of the sensing diaphragm, wherein the second chamber is in fluid connection with the gas outlet port, and
a pilot valve comprising a pilot valve orifice,
wherein the sensing diaphragm has at least an exhalation position and an inhalation position, in the inhalation position, a pressure in the second chamber of the control valve is lower than a pressure in the reference pressure chamber, the sensing diaphragm maintains the pilot valve in an actuated position, and the pilot valve orifice is in fluid connection with the second chamber of the diaphragm valve of the control valve, and in the exhalation position, the pilot valve is not in the actuated position;
a gas powered main valve in fluid connection with the gas inlet port, wherein the main valve comprises a diaphragm valve, wherein the diaphragm valve of the main valve comprises:
a diaphragm;
a first chamber adjacent to a first surface of the diaphragm, and in fluid connection with the pilot valve orifice, and
a second chamber adjacent to a second surface of the diaphragm, and in fluid connection with the gas outlet port,
wherein the diaphragm has a first position in which the gas inlet port and the second chamber of the main valve are substantially not in fluid connection, and a second position in which the gas inlet port and the second chamber of the main valve are in fluid connection, and
wherein the diaphragm is in the second position when the pilot valve is in an actuated position; and
an adjustable backpressure regulator in fluid connection with the gas inlet port and the reference pressure chamber.
16. The demand regulator of claim 15 , wherein the demand valve further comprises a nebulizer valve, wherein the nebulizer valve is a diaphragm valve comprising:
a diaphragm;
a first chamber adjacent to a first surface of the diaphragm, and fluidly connected with the pilot valve orifice;
a second chamber adjacent to a second surface of the diaphragm, and fluidly connected to the gas inlet port; and
a nebulizer valve outlet, wherein
the diaphragm has a first position in which the second chamber of the nebulizer valve is substantially not in fluid connection with the nebulizer valve outlet, and a second position in which the second chamber of the nebulizer valve is in fluid connection with the nebulizer valve outlet, and
when the pilot valve is in the actuated position, the diaphragm of the nebulizer valve is in the second position.
17. A method for providing a breathable gas to a patient in need thereof, the method comprising:
placing a breathing appliance in fluid connection with a patient's airway, wherein the breathing appliance is in fluid connection with the gas outlet port of the demand valve of claim 1 ;
providing a source of pressurized breathable gas to a gas inlet port of the demand valve; and
setting a reference pressure in the demand valve such that an inhalation mode and an exhalation mode of the control valve correspond to an inhalation and an exhalation of the patient, respectively, wherein the reference pressure in the reference chamber remains substantially constant.
18. The method of claim 17 , wherein the reference pressure is set according to the patient's tolerance.