Therapeutic gas flow meter and monitor

A flow meter having a body, an inlet operatively connected to a source of gas, an outlet, and a valve for opening and closing the outlet, the valve including a valve seat, valve shaft movable axially relative to said outlet and a valve member provided on said valve shaft, said valve member movable between a first position in which said valve member engages said valve seat to close said outlet and a second position in which said valve member is spaced from said valve seat to allow gas to pass through said outlet;

• said flow meter further including a sensor which senses the position of said valve member relative to said valve seat and generates a signal indicative of said position;
• said sensor comprising an annular magnet fixed to said valve shaft at a desired axial location along said valve shaft and a magnetorestrictive sensor;
• said magnet producing a magnetic field, said magnetorestrictive sensor being positioned externally of said flow meter and within said magnetic field, said magnetorestrictive sensor generating an output indicative of the strength of said magnetic field for a specified location in the setting of the said shaft, wherein, when said valve shaft and valve member translate axially, the position of the magnet, and hence the magnetic field, move relative to magnetorestrictive sensor, the signal generated by the magnetorestrictive sensor being indicative of the setting of the position of the valve shaft, and hence the valve member.

A flow meter having a body, an inlet operatively connected to a source of gas, an outlet, and a valve for opening and closing the outlet, the valve including a valve seat, valve shaft movable axially relative to said outlet and a valve member provided on said valve shaft, said valve member movable between a first position in which said valve member engages said valve seat to close said outlet, and a second position in which said valve member is spaced from said valve seat to allow gas to pass through said outlet, said flow meter further including a sensor which senses the position of said valve member relative to said valve seat and generates a signal indicative of said position;

• said sensor comprising an emitter which produces an infrared light beam and photo detector which detects infrared light, said emitter and detector being positioned in said meter on opposite sides of said valve member, such that said detector can detect light transmitted perpendicularly across said valve member by said emitter, said valve member having a tapered surface such that as said valve shaft, and hence said valve member translate axially relative to said valve seat, the quantity of light emitted by said emitter which reaches said detector varies, said detector generating an output signal indicative of the amount of light which impinges on said detector, and provides an indication of the position of said valve member;
• a microprocessor including a data storage device, said microprocessor being operatively connected to said sensor to receive said signal generated by the sensor, said microprocessor including means for converting said signal from said sensor into information indicative of the setting of the flow meter valve shaft through passage of the infrared light beam perpendicularly there across, and wherein said microprocessor stores the information in said storage device.