Automotive air bleed valve for a closed hydraulic system
First Claim
Patent Images
1. An automatic bleed valve comprising:
- a plenum chamber;
an air detection system comprising an LED and a photoelectric diode, the LED configured to illuminate the photoelectric diode when air is detected in the plenum chamber;
a first comparator circuit which takes in the output voltage of the photoelectric diode, the first comparator circuit provides a generally constant output voltage when the output voltage of the photoelectric diode corresponds to a voltage signaling that air is detected in the plenum chamber;
an integrator circuit in series with the first comparator circuit, the integrator circuit providing an output voltage to a second comparator circuit which takes in an output of the integrator circuit; and
a vent solenoid which can be actuated to bleed gas from the valve when a predetermined threshold voltage of the second comparator circuit is met by the output voltage of the integrator circuit.
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Accused Products
Abstract
An auto bleed valve and method of bleeding a hydraulic system of an aircraft is accomplished by illuminating a plenum of a bleed valve using an LED oriented to illuminate a phototransistor when air is present in the plenum. A comparator circuit is used on an output of the phototransistor such that a predetermined voltage output corresponds to air detected in the plenum. An integrating circuit and a second comparator in series with the first comparator circuit is used to determine when a predetermined time period is met in which air is continuously detected in the plenum. Thereafter an air bleed solenoid can be used to vent the air upon a signal from the aircraft computer logic system.
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Citations
17 Claims
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1. An automatic bleed valve comprising:
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a plenum chamber; an air detection system comprising an LED and a photoelectric diode, the LED configured to illuminate the photoelectric diode when air is detected in the plenum chamber; a first comparator circuit which takes in the output voltage of the photoelectric diode, the first comparator circuit provides a generally constant output voltage when the output voltage of the photoelectric diode corresponds to a voltage signaling that air is detected in the plenum chamber; an integrator circuit in series with the first comparator circuit, the integrator circuit providing an output voltage to a second comparator circuit which takes in an output of the integrator circuit; and a vent solenoid which can be actuated to bleed gas from the valve when a predetermined threshold voltage of the second comparator circuit is met by the output voltage of the integrator circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An automatic bleed valve comprising:
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a plenum chamber; a sensor for determining if air is present in the plenum chamber; a first analog comparator circuit which takes in an output voltage of the sensor, the first comparator circuit provides a generally constant output voltage when the output voltage of the sensor corresponds to a voltage signaling that air is detected in the plenum chamber; an analog integrator circuit in series with the first comparator circuit, the integrator circuit providing an output voltage to a second analog comparator circuit which takes in an output of the integrator circuit; a vent solenoid which can be actuated to bleed gas from the valve when a predetermined threshold voltage of the second comparator circuit is met by the output voltage of the integrator circuit. - View Dependent Claims (11, 12, 13, 14)
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15. A method of bleeding a hydraulic system of an aircraft comprising the steps of:
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illuminating a plenum of a bleed valve using an LED oriented to illuminate a phototransistor when air is present in the plenum; using a comparator circuit on an output of the phototransistor such that a predetermined voltage output corresponds to air detected in the plenum; determining whether a predetermined time period is met in which air is continuously detected in the plenum using an integrating circuit and a second comparator in series with the first comparator circuit; actuating an air bleed solenoid after the predetermined time period is reached. - View Dependent Claims (16, 17)
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Specification