Patent Application
20220412573
This application claims priority to European Patent Application No. 21182201.0 filed Jun. 28, 2021, the entire contents of which is incorporated herein by reference.
This disclosure relates to a steam oven for an aircraft galley, and to a method of operating a steam oven in an aircraft galley.
Aircraft can be equipped with steam ovens for cooking or heating food for passengers of the aircraft. The steam ovens are typically provided as part of a galley insert which enables easy installation and removal of the oven from an aircraft galley. The food is heated in a food preparation chamber of the oven using steam. The steam can be provided by supplying water to the oven and heating the water within the oven to evaporate it, or by injecting steam into the oven directly. Valves are used to control the water or steam supply to the chamber. Control of these valves is important, since a failure thereof can cause the oven to flood with hot water or steam, leading to possible injuries to flight attendants or passengers.
According to one aspect of the present disclosure there is provided a steam oven for an aircraft galley, comprising: a pipeline for supplying fluid comprising water or steam to a food preparation chamber of the steam oven, the pipeline being configured to receive water or steam from a source external to the steam oven; a valve configured to regulate the flow of said fluid through the pipeline, the valve having an open state in which the valve permits the flow of said fluid through the pipeline and a closed state in which the valve prevents the flow of said fluid through the pipeline; and a control unit configured to actuate the valve between the open and closed states; wherein the valve comprises a sensor configured to detect an actual state of the valve, the sensor being independent of the control unit.
In an optional example, the valve and the sensor are configured to receive power from separate and independent power supplies. The valve may be electrically connected to a first power supply to receive power therefrom and the sensor may be electrically connected to a second power supply to receive power therefrom, wherein the second power supply is electrically isolated from the first power supply.
In an optional example, the actuation of the valve by the control unit is not based on the valve state detection by the sensor.
In an optional example, the valve comprises a circuit board including the sensor, wherein the circuit board is arranged to receive and process sensor data from the sensor and output a signal indicative of the actual valve state based on the sensor data. In another optional example, the sensor is configured to transmit sensor data to a remote electronics unit for processing.
The valve may optionally be a normally-closed solenoid valve. The solenoid valve may comprise a solenoid and a plunger, wherein the solenoid, when powered, may move the plunger from an extended position in which the plunger extends into the pipeline to block the passage of fluid therethrough, to a retracted position in which the plunger is retracted from the pipeline to permit the passage of fluid therethrough. The sensor may be arranged to detect whether the plunger is in the extended position or the retracted position. The solenoid valve may optionally comprise a biasing member arranged to bias the plunger to the extended position when the solenoid is not powered. In an example, the biasing member is a spring.
In an optional example, the steam oven comprises a verification circuit configured to verify that the expected valve state corresponds to the actual state of the valve detected by the sensor. The expected valve state may be the expected state of the valve after receiving an actuation command from the control unit.
An aspect of the present disclosure provides an aircraft galley insert comprising a steam oven as disclosed herein.
An aspect of the present disclosure provides a method of operating a steam oven in an aircraft galley, comprising: flowing fluid comprising water or steam through a pipeline towards a food preparation chamber of the steam oven; using a control unit, actuating a valve to regulate the flow of said fluid through the pipeline, the valve having an open state in which the valve permits the flow of said fluid through the pipeline and a closed state in which the valve prevents the flow of said fluid through the pipeline; and detecting an actual state of the valve using a sensor on the valve, the sensor being independent of the control unit.
In an optional example, the method comprises powering the valve and the sensor using separate and independent power supplies.
Optionally, the actuation of the valve by the control unit is not based on the valve state detection by the sensor.
In an optional example, the valve comprises a circuit board including the sensor. The method may comprise using the circuit board to receive and process sensor data from the sensor and generate a signal indicative of the actual valve state based on the sensor data.
In another optional example, the method comprises transmitting sensor data from the sensor to a remote electronics unit for sensor data processing.
The valve may optionally be a normally-closed solenoid valve. The method may comprise powering a solenoid of the solenoid valve and thereby causing a plunger of the solenoid valve to move from an extended position in which the plunger extends into the pipeline to block the passage of fluid therethrough, to a retracted position in which the plunger is retracted from the pipeline to permit the passage of fluid therethrough. The sensor may detect whether the plunger is in the extended position or the retracted position. The method may comprise biasing the plunger to the extended position using a spring when the solenoid is not powered.
The method may optionally comprise verifying that an expected valve state corresponds to the actual valve state detected by the sensor. The expected valve state may be the expected state of the valve after receiving an actuation command from the control unit.
An aspect of the present disclosure provides a method of operating a steam oven as disclosed herein.
Certain embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings.
In some embodiments (not shown), the steam oven 1 may instead receive steam from an external supply, rather than water. Thus the steam oven 1 may not comprise the heating element 6 and the nozzle 7, and the pipeline 5 may be arranged to supply steam directly from the external supply to the food preparation chamber 4.
The pipeline 5 comprises a valve 9 configured to regulate the flow of water (or steam) through the pipeline 5. The valve 9 has an open state in which the valve 9 permits the flow of fluid through the pipeline 5, and a closed state in which the valve 9 prevents the flow of fluid through the pipeline 5. The pipeline 5 may further comprise additional valves 9 configured in this way. In this example, the valve 9 is a solenoid valve 9. However, other valve types may be used.
The solenoid valve 9 is electrically connected to a control unit 10. The control unit 10 is configured to actuate the valve 9 between the open and closed states. The control unit 10 can transmit a command signal to the valve 9 corresponding to a desired state of the valve 9. For example, an “open” command signal may be transmitted when it is desired for the valve 9 to be in an open state, and a “close” command signal may be transmitted when it is desired for the valve 9 to be in a closed state. If the valve 9 is operating correctly, then the valve 9 will be actuated according to the command signal. An expected valve state is the state in which the valve 9 is expected to be after receiving an actuation command from the control unit 10, assuming the valve and control unit are operating correctly.
The valve 9 comprises a sensor 11 configured to detect an actual state of the valve 9. The actual valve state is the state which the valve 9 is actually in after receiving an actuation command from the control unit 10. The sensor 11 will be described in more detail later with reference to
The actual valve state may differ from the expected valve state if there is a fault in the system. For instance, a fault in the control unit 10 may cause an “open” command signal to be transmitted to the valve 9, when it was desired to close the valve 9. In another example, a fault in the valve 9 may cause the valve 9 to remain in an open or partially open state, even after receiving a “close” command signal from the control unit 10. In some embodiments, the sensor 11 can be used to verify whether the expected valve state corresponds to the actual valve state.
The solenoid valve 9 comprises a solenoid 12 and a plunger 13 which are arranged such that the solenoid 12, when powered, moves the plunger 13 from an extended position in which the plunger 13 extends into the pipeline 5 to block the passage of fluid therethrough, to a retracted position in which the plunger 13 is retracted from the pipeline 5 to permit the passage of fluid therethrough.
The solenoid 12 of the solenoid valve 9 is configured to receive power from the control unit 10 to energise the solenoid 12. The control unit 10 therefore actuates the valve 9 by selectively powering the solenoid 9. In this example, an “open” command signal transmitted by the control unit 10 to the valve 9 provides power to the solenoid 12 which causes the solenoid 12 to move the plunger 13 to the retracted position using electromagnetic forces, and a “closed” command signal transmitted by the control unit 10 to the valve 9 ceases power to the solenoid 12.
The solenoid valve comprises a spring 14 arranged to bias the plunger 13 to the extended position. Thus, when there is no power to the solenoid 12, the plunger 13 is urged into the extended position by the biasing action of the spring 14 (as shown in
The solenoid valve 9 is a normally-closed valve since the spring 14 biases the plunger 13 to the extended position. A normally-closed valve can provide safety benefits since the water or steam is normally prevented from reaching the food preparation chamber, thus decreasing the risk of flooding in the oven.
The sensor 11 is arranged to detect whether the plunger 13 is in the retracted position or the extended position. The sensor 11 may comprise any suitable sensor type. Examples include optical sensor, magnetic sensor, ultrasonic sensor, etc. The most suitable type of sensor may depend on the type of valve being used.
In one illustrative example, the sensor 11 comprises an optical sensor 11 arranged such that, when the plunger 13 is in the retracted position, the plunger 13 blocks a light path of the optical sensor 11, and when the plunger 13 is in the extended position, the plunger 13 does not block the light path of the optical sensor 11. Thus, the sensor data will indicate that the actual valve state is an open state when the data corresponds to the light path being blocked, and the sensor data will indicate that the actual valve state is a closed state when the data corresponds to the light path not being blocked. In other examples the optical sensor 11 may be arranged oppositely, such that the plunger 13 being in the retracted position does not block a light path of the optical sensor 11, and the plunger 13 being in the extended position blocks the light path of the optical sensor 11.
The sensor 11 and the valve 9 are configured such that the detection of the actual valve state by the sensor 11 is independent of control of the valve 9 by the control unit 10.
The actuation of the valve 9 by the control unit 10 is not based on the valve state detection by the sensor 11. That is, the command signal transmitted by the control unit 10 to the valve 9 is independent of (e.g. is not based on and/or does not depend on) measurements by the sensor 11. In some embodiments, the control unit 10 and/or the valve 9 may be electrically isolated from the sensor 11. This is beneficial since the circuitry for controlling the valve actuation is then not a possible common cause of failure of the valve 9 and the sensor 11.
In some embodiments the sensor 11 directly detects the physical location of the plunger 13, rather than inferring the plunger location e.g. by monitoring the current in the solenoid 12. This is because if the valve and the sensor are dependent on the same current, then in the case of a failure the sensor 11 would not be able to independently verify the valve state. In addition, such sensors can be costly and complex.
The valve 9 and the sensor 11 are configured to receive power from separate and independent (e.g. electrically isolated) power supplies (not shown). In examples in which the valve 9 receives power from the control unit 10, e.g. in the form of command signals, the control unit 10 may be configured to receive power from a first power supply that is independent of a second power supply providing power to the sensor 11. This can be advantageous since a failure of the first power supply would not affect operation of the sensor 11, and a failure of the second power supply would not affect operation of the valve 9, so that the power supply is not a possible common cause of failure of the valve 9 and the sensor 11. The steam oven 1 may comprise the two power supplies for separately powering the valve 9 (and/or control unit 10) and the sensor 11.
The sensor 11 outputs sensor data about the actual valve state for processing. In some embodiments, the sensor 11 outputs the sensor data to a circuit board (not shown) located on or proximate to the valve 9. The circuit board may comprise the sensor 11, and may be arranged to receive and process the sensor data from the sensor 11 and output a signal indicative of the actual valve state based on the sensor data. In other embodiments, the sensor 11 is configured to transmit the sensor data to an electronics unit (not shown) which is located remotely from the valve 9. The transmission may be wired or wireless, for instance. The remote electronics unit may process the sensor data and output a signal indicative of the actual valve state based on the sensor data.
The state of the valve 9 can be verified by comparing the actual valve state as measured by the sensor 11 to the expected valve state as expected based on the command signal from the control unit 10. The steam oven 1 may comprise a verification circuit (not shown) configured to perform this comparison. The verification circuit may be configured to receive the signal indicative of the actual valve state based on the sensor data (e.g. from the circuit board or the remote electronics unit) and to receive a signal indicative of the expected valve state (e.g. from the control unit 10), and to compare or cross-check the signals. It can then be verified whether the expected valve state corresponds to the actual valve state. If there is a discrepancy, this may indicate a fault with the valve 9 or the control unit 10. The verification circuit may be part of the control circuitry for general operation of the steam oven 1.
As mentioned previously, although only one valve 9 is shown in the Figures, the steam oven 1 may comprise further valves 9 configured in the same way on pipeline 5. In an example, two solenoid valves 9 are provided. The multiple valves 9 may share a common control unit 10 or they may each receive actuation signals from separate control units 10. The multiple valves 9 may each have their own sensor 11 for detecting the actual state of the respective valve 9. This advantageously provides redundancy in case of a valve failure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21182201.0 | Jun 2021 | EP | regional |
