Oxygen blending in a piston ventilator
First Claim
1. A patient ventilator comprising:
- a piston and cylinder assembly including a cylinder and a piston reciprocally received in said cylinder for movement along a retracting gas intake stroke and a protracting gas expelling stroke to define a variable volume chamber therebetween;
a patient circuit for delivering breathable gas from said piston and cylinder assembly to a patient during patient inhalation;
a controller connected to said piston and cylinder assembly for receiving input corresponding to the position of the piston within the cylinder during the intake stroke; and
an oxygen blending module fluidically connected to said chamber of said piston and cylinder assembly for controlling delivery of oxygen from an oxygen source to the piston and cylinder assembly for blending with the breathable gas in the chamber, said oxygen blending module including a first oxygen control valve operatively connected to said controller and a flow sensor for providing a signal to said controller representative of an amount of oxygen delivered from the first oxygen control valve, wherein said controller calculates a target amount of oxygen in said piston and cylinder assembly based on the position of the piston during the intake stroke, calculates a difference between said target amount and a calculated actual amount of oxygen delivered past said flow sensor based on the signal provided by the flow sensor and directs a control signal for opening and closing the first oxygen control valve based on said calculated difference during said intake stroke.
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Accused Products
Abstract
A piston ventilator is disclosed herein which uniquely includes an oxygen blending module which supplies oxygen enhancement for aiding patients requiring respiratory treatment. The oxygen blending module supplies a preselected enrichment of oxygen to a piston and cylinder assembly wherein the amount of oxygen permitted to flow therein is continuously monitored and controlled according to the volume above the piston in the cylinder as calculated by a controller. The oxygen blending module includes a flow sensor which monitors the flow of supplemental oxygen into the piston and cylinder assembly, and further includes a primary oxygen control valve which restricts the flow of oxygen through the flow sensor to the piston and cylinder assembly depending on the difference between the calculated desired amount of oxygen and the target amount of oxygen provided to the controller.
248 Citations
12 Claims
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1. A patient ventilator comprising:
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a piston and cylinder assembly including a cylinder and a piston reciprocally received in said cylinder for movement along a retracting gas intake stroke and a protracting gas expelling stroke to define a variable volume chamber therebetween;
a patient circuit for delivering breathable gas from said piston and cylinder assembly to a patient during patient inhalation;
a controller connected to said piston and cylinder assembly for receiving input corresponding to the position of the piston within the cylinder during the intake stroke; and
an oxygen blending module fluidically connected to said chamber of said piston and cylinder assembly for controlling delivery of oxygen from an oxygen source to the piston and cylinder assembly for blending with the breathable gas in the chamber, said oxygen blending module including a first oxygen control valve operatively connected to said controller and a flow sensor for providing a signal to said controller representative of an amount of oxygen delivered from the first oxygen control valve, wherein said controller calculates a target amount of oxygen in said piston and cylinder assembly based on the position of the piston during the intake stroke, calculates a difference between said target amount and a calculated actual amount of oxygen delivered past said flow sensor based on the signal provided by the flow sensor and directs a control signal for opening and closing the first oxygen control valve based on said calculated difference during said intake stroke. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of blending oxygen with breathable gas in a piston ventilator comprising the steps of:
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providing a pressurized source of oxygen and a piston ventilator, said ventilator including a piston and cylinder assembly having a reciprocating piston shiftable within a cylinder during a retracting gas intake stroke and a protracting gas expelling stroke to define therebetween a variable volume chamber, a first path for fluidically connecting said oxygen source to said piston and cylinder assembly to deliver oxygen to said chamber, said first path including a flow sensor and a first oxygen control valve, a patient circuit located fluidically downstream from said piston and cylinder assembly for delivering breathable gas to a patient, and a controller connected to said piston and cylinder assembly, said flow sensor and said first control valve;
retracting said piston within said cylinder to intake breathable gas into said chamber;
monitoring the position of said piston within said cylinder during retraction;
delivering a signal to said controller from said piston and cylinder assembly representative of said position of the piston;
delivering oxygen from said source through said first path to said chamber of said piston ventilator during retraction of said piston;
monitoring a flow of oxygen past said flow sensors along said first path;
delivering a signal to said controller from said flow sensor representative of an amount of oxygen flowing past the flow sensor;
calculating in said controller the amount of oxygen delivered to said chamber of said piston and cylinder assembly from said first path during retraction of the piston based on said signal from said flow sensor;
comparing said calculated amount of delivered oxygen to a preselected value corresponding to a target amount of oxygen desired to be delivered to said piston and cylinder assembly based on the piston position signal and calculating a difference between the calculated amount and the preselected value;
generating a control signal in said controller corresponding to said calculated difference and delivering said control signal to said oxygen control valve; and
adjusting the flow of oxygen to be delivered to said chamber through said oxygen control valve responsive to said control signal. - View Dependent Claims (11, 12)
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Specification