Solenoid controlled respiratory gas demand valve
A prior art demand valve has been modified to make it more responsive to persons with impaired oxygen delivery by replacing its sensing diaphragm and associated mechanically actuated valve actuator with a solenoid activated proportional control valve coupled to an analog pressure transducer via a pulse width modulated current driver circuit. The pressure transducer responds to detected pressure changes in a patient's breathing tube.
1. A solenoid controlled respiratory gas demand valve comprising:
a) a valve body having a supply gas port leading from an exterior surface of the valve body to an interior chamber, a valve seat member disposed between the interior chamber and a patient circuit outlet port and a bleed gas exhaust path leading to the patient circuit outlet port, the valve body including an annular collar;
b) a valve plate member sealingly attached to the annular collar of the valve body, the valve plate member including an upper surface and a lower surface, the lower surface including an integrally formed nose portion extending outwardly therefrom and centered with respect to the valve seat member and the upper surface including a cylindrical socket, there being a first bore extending from a bottom of the socket and through said nose portion;
c) a generally circular elastic diaphragm having a peripheral portion captured between the valve body and the valve plate member and overlaying said nose portion, the diaphragm including a bleed port extending through a thickness dimension thereof; and
d) a solenoid-operated proportional valve mounted on the upper surface of the valve plate member, the solenoid-operated proportional valve having a cylindrical boss fitting into said cylindrical socket, the solenoid-operated proportional valve having a displaceable, electrically-actuated poppet for selectively blocking and unblocking a second bore extending through said boss and leading to said first bore in the valve plate.
2. The solenoid controlled respiratory gas demand valve of claim 1 and further including a tubular, gas-permeable, filter member located in the interior chamber of the valve body in surrounding relation to the valve seat member of the valve body and a captured portion of the elastic diaphragm.
3. The solenoid controlled respiratory gas demand valve of claim 1 wherein the solenoid-operated proportional valve and the valve plate member include joined passageways, including the first and second bores, leading from an area surrounding the poppet to the patient circuit outlet port.
4. The solenoid controlled respiratory gas demand valve of claim 1 and further including a supply gas fitting coupled to the supply gas port of the valve body.
5. The solenoid controlled respiratory gas demand valve of claim 3 and further including an electronic pressure transducer disposed in a patient circuit coupled to the patient circuit outlet port of the valve body, the pressure transducer being coupled through a valve driver to the solenoid-operated proportional valve.
6. A solenoid-controlled respiratory gas demand valve comprising:
a) a valve body having a supply gas port leading from an exterior surface of the valve body to an interior chamber, a valve seat member disposed between the interior chamber and a patient circuit outlet port and a bleed gas exhaust path leading to the patient circuit outlet port, the valve body including an annular collar;
b) a valve plate member sealingly attached to the annular collar of the valve body, the valve plate member including an upper surface and a lower surface, the lower surface including an integrally formed nose portion extending outwardly therefrom and centered with respect to the valve seat member and the upper surface including a cylindrical socket, there being a first bore extending from a bottom of the cylindrical socket and through said nose portion;
c) an elastic diaphragm captured between the valve body and the valve plate member and overlaying said nose portion, the diaphragm including a bleed port extending through a thickness dimension thereof; and
d) a solenoid-operated proportional valve having a displaceable poppet for selectively blocking and unblocking a lumen of an elongated tube joined between the solenoid-operated proportional valve and said first bore.
7. The solenoid-controlled respiratory gas demand valve of claim 1 or claim 6 and further including a pressure sensor mounted to sense pressure within the patient circuit and to produce a DC voltage signal output in response to the sensed pressure, and a pulse width modulated proportional valve driver for connecting the FC voltage signal output of the pressure sensor to the solenoid-operated proportional valve.