초록 ▼

A sensor for detecting icing conditions in an airstream includes a flow housing mounted on an aircraft and in which one or more probes are mounted. At least one of the probes subjected to impingement of the airstream and liquid moisture droplets in such airstream. The heat removal, or cooling effect

A sensor for detecting icing conditions in an airstream includes a flow housing mounted on an aircraft and in which one or more probes are mounted. At least one of the probes subjected to impingement of the airstream and liquid moisture droplets in such airstream. The heat removal, or cooling effect on the probe in the airstream carrying liquid droplets is determined. A temperature signal indicating the airstream temperature is combined with signals from the at least one probe for determining whether or not icing conditions are present.

대표청구항 ▼

What is claimed is: 1. A sensor for detecting icing conditions in an airflow caused by presence of liquid moisture in such airflow, the sensor including a flow housing having a channel providing at least one flow path configured to provide a known mass airflow rate therethrough at relative airflow

What is claimed is: 1. A sensor for detecting icing conditions in an airflow caused by presence of liquid moisture in such airflow, the sensor including a flow housing having a channel providing at least one flow path configured to provide a known mass airflow rate therethrough at relative airflow speeds, at least one probe mounted in the at least one flow path such that the airflow impinges on the probe, a power source for heating the probe, and a sensing circuit coupled to the probe for determining changes in a function which is dependent upon the presence of liquid moisture striking the probe, the sensing circuit providing an output indicating changes in the function, wherein said sensing circuit comprises a bridge circuit, and wherein the probe comprises a first probe and has a known resistance relationship with temperature, a second probe mounted in a second airflow path that is branched from the at least one airflow path and which has airflow that is substantially free of liquid moisture, and wherein the bridge circuit compares temperatures between the first probe and the second probe. 2. The sensor of claim 1 including a third probe mounted in the second airflow path, said third probe comprising a temperature sensor for determining temperature of air flowing across both the first and second probes. 3. The sensor of claim 1 wherein said at least one airflow path and said second airflow path are defined in a single airflow housing, said second airflow path having an inlet opening that is lateral of the path of movement of air in the at least one airflow path such that the heavier particles in the at least one airflow path are carried past the inlet opening of the second airflow path. 4. A sensor for sensing icing conditions in an airflow caused by presence of liquid moisture in such airflow, said sensor including a flow housing having a first flow path configured to have airflow of known mass flow rates therethrough at different airflow speeds, a first probe mounted in said first airflow path in position to be impinged by the airflow and by liquid moisture in the airflow, the first probe being heatable in response to a power input, the first probe indicating temperature by changes in a temperature sensing element in the first probe, a circuit connected to the first probe to provide heating power to heat the first probe to a selected temperature above ambient temperature, and a circuit connected to the first probe to determine the amount of heat removed from the first probe above a known value of heat removal in dry air flowing at the same mass airflow rate as the mass airflow rate through the first flow path to determine if moisture in the airflow in the first flow path is causing heat to be removed from the first probe. 5. The sensor of claim 4, wherein said flow housing has a branch flow path positioned relative to the flow direction through the first flow path such that liquid moisture is inertially separated and maintained in the first flow path, and airflow through the branch flow path being substantially free of liquid moisture, a second probe in the branch flow path, and wherein the circuit includes components to compare the changes in relative heat removal between the first and second probes. 6. The sensor of claim 5, wherein said circuit further comprises a computer receiving signals that indicate when liquid moisture is present in the airflow through the first flow path, and receiving a temperature signal indicating ambient temperature, the computer providing an output signal indicating the presence of icing conditions when the ambient temperature is below a selected level and liquid moisture is indicated as being present. 7. The sensor of claim 6, wherein the computer receives a set point signal, and compares the set point signal to the ambient temperature, the computer providing the output indicating icing conditions when a signal indicating liquid moisture is present and the ambient temperature is below the set point signal. 8. The sensor of claim 5 wherein the branch flow path is defined in a portion of the flow housing having a forwardly facing wall, a heater for heating the wall for deicing the forwardly facing wall of the flow housing, and a baffle between the forwardly facing wall and the second probe to reduce the influence of heaters for heating the forwardly facing wall. 9. The sensor of claim 4, wherein the signal from the circuit varies as a function of the quantity of liquid moisture present in the first flow path as related to the amount of heat removed from the first probe. 10. The sensor of claim 5, wherein a third probe for sensing temperature is mounted in the branch flow path, and is included in the circuit to provide a temperature signal for determining the presence of liquid moisture in the first flow path. 11. The sensor of claim 10, wherein the third probe is positioned upstream from the second probe in the branch flow path. 12. The sensor of claim 10 wherein the circuit is a resistance bridge circuit, and wherein the temperature signal is provided at terminals of the bridge circuit. 13. A sensor for sensing icing conditions in an airflow caused by presence of liquid moisture in such airflow, said sensor including a flow housing having a flow path that is configured to provide airflow in a substantially straight line, the flow housing having a laterally facing outlet opening leading from the flow path to a passage, the flow path including a first branch flow path downstream of the laterally facing opening, and said passage comprising a second branch flow path, a first temperature sensor probe mounted in said first branch flow path, a second temperature sensing probe mounted in said second branch flow path, the laterally facing opening being positioned such that airflow passing through the laterally facing opening is substantially free of liquid moisture, and a bridge circuit connected to resistances in said first and second probes to compare differentials in temperature between temperature sensed by said first and second probes, respectively. 14. The sensor of claim 13, wherein said first and second branch flow paths are controlled to have substantially the same mass flow rates of air carried therein. 15. The sensor of claim 14, and a temperature sensing probe in said second branch flow path positioned to be impinged by airflow in said second branch flow path prior to the airflow in said second branch flow path impinging on said second probe. 16. The sensor of claim 15, wherein said third probe is a resistance temperature sensing probe, and is connected in the bridge circuit to provide an indication of temperature at selected terminals of the bridge circuit. 17. The sensor of claim 13, wherein said first and second probes are heated, and are maintained at temperatures substantially above ambient temperature of the airflow. 18. The sensor of claim 13, wherein the flow housing has boundary layer control orifices through a wall of the flow housing defining the flow path. 19. The sensor of claim 13, and a baffle plate in the first branch flow path between a leading edge of the flow housing defining the first branch flow path and the first temperature sensor probe. 20. The sensor of claim 13, and a computer connected to the bridge circuit to receive signals indicating differentials between temperatures sensed by said first and second probes, the computer having an input receiving a signal indicating ambient temperature, and providing an output indicating icing conditions when liquid moisture is indicated by the differential in temperatures between the first and second probes, and the ambient temperature is below a selected level near freezing. 21. The sensor of claim 20, wherein the computer receives a set point signal, the computer providing the output indicating icing conditions when the ambient temperature signal is below the set point signal.