Patent Description:
Inflatable evacuation systems may be found on various structures, including aircraft, boats, offshore drilling platforms, and the like. The systems are typically equipped with an inflatable device, such as, for example, an inflatable slide or an inflatable raft, configured to facilitate rapid evacuation of persons in the event of an emergency. The slides or rafts are typically stored in an uninflated condition on the structure - e.g., a commercial aircraft - in a location readily accessible for deployment.

Systems used to inflate the slide or raft typically employ gas stored within a cylinder or tank at high pressure, which is discharged into the inflatable. Due to changes in the densities of gasses caused by variations in temperature, the volume of gas needed to achieve the desired inflation pressure varies with ambient temperature. In this regard, a greater volume of gas is needed to achieve the desired inflatable pressure at low ambient temperatures as compared to the volume of gas needed to achieve the desired pressure at higher ambient temperatures. The volume of gas stored in the pressurized cylinder and provided to the inflatable is configured to ensure that, even at the lowest ambient temperatures, the desired pressure within the inflatable is achieved. Thus, a greater volume of gas than what is needed and/or desired may be provided to the inflatable, particularly at higher ambient temperatures. To prevent over-inflation, current slides and rafts generally include one or more pressure relief valve(s) (PRVs) through which the excess gas may be vented. Some slides and rafts may also include (or may alternatively include) pressure and/or stretch sensors as part of a closed loop system to control the pressure within the inflatable during the inflation process. The PRVs and/or sensors tend to increase manufacturing, packaging, assembly, and/or maintenance requirements for the inflatable.

An inflation control system of the prior art is known from <CIT> which, according to its abstract, discloses an inflation control system including a valve module and a controller. The valve module includes a first valve fluidly connected to a fluid source, a second valve fluidly connected to the first valve, and a pressure regulator fluidly connected to the second valve and an aspirator. The controller is in communication with the first valve.

An inflation control system for an inflatable as defined in claim <NUM> is provided. In accordance with various embodiments, the inflation control system may comprise a compressed fluid source and a valve module connected to the compressed fluid source. The valve control module may be configured to control a flow of gas to the inflatable. A temperature sensor may be configured to measure an ambient temperature and output an ambient temperature measurement. A controller may be operably coupled to the valve module. The controller may be configured to receive the ambient temperature measurement and determine an open-valve time based on the ambient temperature measurement, the open-valve time being a duration of time the valve module is in an open position.

In various embodiments, the controller may be configured to access an open-time versus temperature database. The controller may determine the open-valve time by looking up the ambient temperature measurement in the open-time versus temperature database and determining the open-valve time associated with the ambient temperature measurement.

In various embodiments, the valve module may include a main pneumatic valve configured to start and to stop the flow of gas. In various embodiments, the valve module may include a solenoid control valve connected to the controller and configured to operate the main pneumatic valve. The controller may be configured to energize the solenoid control valve for a length of time equal to the open-valve time. In various embodiments, the solenoid control valve may be a normally open valve.

In various embodiments, the valve module may include a pressure regulator valve. In various embodiments, an aspirator may be fluidly connected between the valve module and the inflatable. The temperature sensor may be mounted to the aspirator.

An evacuation system for an aircraft is also disclosed herein. In accordance with various embodiments, the evacuation system may comprise an inflatable tube and a compressed fluid source fluidly coupled to the inflatable tube. A valve module may be connected to the compressed fluid source and configured to control a flow of gas from the compressed fluid source to the inflatable tube. A temperature sensor may be configured to measure an ambient temperature and output an ambient temperature measurement. A controller may be operably coupled to the valve module. The controller may be configured to receive the ambient temperature measurement from the temperature sensor and determine an open-valve time based on the ambient temperature measurement, the open-valve time being a duration of time the valve module is in an open position.

In various embodiments, the valve module may include a main pneumatic valve configured to start and to stop the flow of gas from the compressed fluid source to the inflatable tube. In various embodiments, the valve module may include a solenoid control valve operably coupled to the controller and configured to operate the main pneumatic valve. In various embodiments, the controller may be configured to energize the solenoid control valve for a length of time equal to the open-valve time. In various embodiments, the solenoid control valve may be a normally open valve.

In various embodiments, the controller may be configured to start a timer corresponding to the open-valve time. The controller may be configured to de-energize the solenoid control valve in response to expiration of the timer. In various embodiments, an aspirator may be fluidly connected between the valve module and the inflatable tube. The temperature sensor may be mounted to the aspirator.

An article of manufacture including a tangible, non-transitory computer-readable storage medium having instructions stored thereon for controlling inflation of an evacuation slide is also disclosed herein, and defined in claim <NUM>. In accordance with various embodiments, the instructions, in response to execution by a controller, cause the controller to perform operations, which may comprise receiving, by the controller, an ambient temperature measurement; determining, by the controller, an open-valve time based on the ambient temperature measurement; sending, by the controller, a first control signal to a valve module fluidly coupled between a compressed fluid source and the evacuation slide; starting, by the controller, a timer corresponding to the open-valve time; and sending, by the controller, a second control signal to the valve module after expiration of the timer. The first control signal may be configured to cause the valve module to translate from a closed position to an open position. In the open position, gas may flow from the compressed fluid source to the evacuation slide. The second control signal may be configured to cause the valve module to translate from the open position to the closed position. In the closed position, gas from the compressed fluid source may be prevented from flowing into the evacuation slide.

In various embodiments, determining, by the controller, the open-valve time based on the ambient temperature measurement may comprise accessing, by the controller, an open-time versus temperature database.

In various embodiments, sending, by the controller, the first control signal to the valve module may comprise energizing, by the controller, a solenoid control valve, the solenoid control valve being configured to operate a main pneumatic valve.

In various embodiments, the operations may further comprise determining, by the controller, a duration of time to energize the solenoid control valve using the open-time versus temperature database. In various embodiments, the solenoid control valve may be a normally open valve.

The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the exemplary embodiments of the disclosure, it should be understood that other embodiments may be realized and that logical changes and adaptations in design and construction may be made in accordance with this disclosure and the teachings herein, if within the scope of the appended claims. Thus, the detailed description herein is presented for purposes of illustration only and not limitation.

Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option.

Surface lines may be used throughout the figures to denote different parts but not necessarily to denote the same or different materials. Throughout the present disclosure, like reference numbers denote like elements. Accordingly, elements with like element numbering may be shown in the figures, but may not necessarily be repeated herein for the sake of clarity.

The systems and methods disclosed herein may find particular use in connection with aircraft evacuation slides. However, various aspects of the disclosed systems and methods may be adapted for performance in a variety of other inflatable assemblies, for example, inflatable raft assemblies, and/or any other assemblies having inflatable structures. As such, numerous applications of the present disclosure may be realized.

Referring now to <FIG>, an aircraft <NUM> is shown. Aircraft <NUM> may include a fuselage <NUM> having plurality of exit doors, including an exit door <NUM>. Aircraft <NUM> may include one or more evacuation systems positioned near a corresponding exit door. For example, aircraft <NUM> includes an evacuation system <NUM> positioned near exit door <NUM>. In the event of an emergency, exit door <NUM> may be opened by a passenger or crew member of aircraft <NUM>. In various embodiments, evacuation system <NUM> may deploy in response to exit door <NUM> being opened. It is contemplated and understood that evacuation system <NUM> may deploy in response to other actions taken by a passenger or crew member such as depression of a button, actuation of a lever, or the like.

With reference to <FIG>, evacuation system <NUM> is illustrated with the evacuation slide in an inflated or "deployed" position. In accordance with various embodiments, evacuation system <NUM> includes an evacuation slide <NUM> and a compressed fluid source <NUM> configured to deliver a pressurized gas to inflate evacuation slide <NUM>. During deployment, an inflatable tube <NUM> (or a plurality of inflatable tubes) of evacuation slide <NUM> is inflated using pressurized gas from compressed fluid source <NUM>. Evacuation slide <NUM> may comprise a sliding surface <NUM> secured to the inflatable tube <NUM> and configured for sliding passenger egress from the emergency exit door <NUM> of the aircraft <NUM>, with momentary reference to <FIG>, to a ground surface in the event of an evacuation on land or to a water surface in the event of an evacuation on water. Evacuation slide <NUM> includes a toe end <NUM> and a head end <NUM> opposite toe end <NUM>. Head end <NUM> may be coupled to an aircraft structure (e.g., fuselage <NUM> in <FIG>). Sliding surface <NUM> extends from head end <NUM> to toe end <NUM>. Evacuation slide <NUM> is illustrated as a single lane slide. However, evacuation slide <NUM> may comprise any number of lanes.

Compressed fluid source <NUM> is fluidly coupled to evacuation slide <NUM>. For example, compressed fluid source <NUM> may be fluidly coupled to inflatable tube <NUM> via a hose, or conduit, <NUM>. In various embodiments, evacuation system <NUM> may include an aspirator <NUM> fluidly coupled between compressed fluid source <NUM> and evacuation slide <NUM>. Aspirator <NUM> is configured to entrain ambient air with gas output from compressed fluid source <NUM>. For example, in response to deployment of evacuation slide <NUM>, the gas from compressed fluid source <NUM> flows into aspirator <NUM> and causes aspirator <NUM> to draw in ambient air from the environment. The combination of gas flow from compressed fluid source <NUM> and the environmental gas is then directed into evacuation slide <NUM>, thereby inflating inflatable tube <NUM>.

Referring now to <FIG>, an inflation control system <NUM> for controlling inflation of evacuation slide <NUM> is illustrated. Inflation control system <NUM> includes one or more temperature sensor(s) <NUM> configured to sense or monitor the ambient temperature during the inflation process. As described in further detail below, inflation control system <NUM> employs real-time temperature data to determine how long (i.e. a duration of time) gas should be provide to evacuation slide <NUM> to achieve a desired inflation pressure.

Inflation control system <NUM> includes a valve module <NUM>, compressed fluid source <NUM>, which is filled with a high-pressure gas (or, in various embodiments, a gas generator configured to generate a high-pressure gas), aspirator <NUM>, a controller <NUM>, and a power source <NUM>, such as, for example, a battery or charged capacitor. In various embodiments, the power source <NUM> is a dedicated source configured to power the temperature sensor <NUM>, as well as each of the valve module <NUM> and the controller <NUM>. To provide a dedicated source of direct current power, the power source <NUM> may comprise, for example, a lithium-ion battery or an ultracapacitor, each configured to store energy at a high density for controlling the rapid sequence of events that occur during an inflation process of the evacuation slide <NUM>. As illustrated in <FIG>, real-time data from the temperature sensor <NUM> (i.e., ambient temperature measurements) are transmitted to the controller <NUM> via a temperature sensor bus <NUM>. In various embodiments, the controller <NUM> may include a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or some other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. A tangible, non-transitory computer-readable storage medium <NUM> may be in communication with controller <NUM>. Storage medium <NUM> may comprise any tangible, non-transitory computer-readable storage medium known in the art. The storage medium <NUM> has instructions stored thereon that, in response to execution by controller <NUM>, cause controller <NUM> to perform operations related to controlling the inflation of evacuation slide <NUM>.

In accordance with various embodiments, the valve module <NUM> is configured to open and close a main pneumatic valve <NUM> based on a control signal received from the controller <NUM>. More specifically, based on preset control logic and the real-time data received from the temperature sensor <NUM>, controller <NUM> opens or closes the main pneumatic valve <NUM> in order to turn on or turn off the flow of high-pressure gas from the compressed fluid source <NUM> to the inflatable tube <NUM>. In various embodiments, the valve module <NUM> may further comprise a control valve <NUM> configured to operate the main pneumatic valve <NUM> between an open position and a closed position. In various embodiments, the valve module <NUM> may also include a pressure regulator valve <NUM> configured to prevent the occurrence of an overpressure situation at the aspirator <NUM> or the inflatable tube <NUM>.

With reference to <FIG>, additional details of control valve <NUM> and main pneumatic valve <NUM> are illustrated. In various embodiments, control valve <NUM> may be a normally open valve, such as, for example, a three-way, two-position normally open solenoid valve, and main pneumatic valve <NUM> may be a normally closed poppet valve. In this regard, energizing control valve <NUM> (i.e. providing electric current to control valve <NUM>), as shown in <FIG>, opens the main pneumatic valve <NUM>. De-energizing control valve <NUM> (i.e. stopping the flow of electric current to control valve <NUM>), as shown in <FIG>, closes main pneumatic valve <NUM>.

Referring to <FIG>, prior to deployment of the evacuation slide <NUM>, control valve <NUM> is de-energized (i.e., no current is being supplied to control valve <NUM>). In the de-energized state, control valve <NUM> is open and gas, from compressed fluid source <NUM>, flows from control valve <NUM> into an upper chamber <NUM> of main pneumatic valve <NUM>. The flow of gas into upper chamber <NUM> increases the pressure in upper chamber <NUM> and forces a poppet <NUM> of main pneumatic valve <NUM> toward an inlet <NUM> of main pneumatic valve <NUM>. The pressure and/or force applied to poppet <NUM> locates poppet <NUM> in a position that blocks an outlet <NUM> of main pneumatic valve <NUM>. Stated differently, the gas in upper chamber <NUM> forces main pneumatic valve <NUM> into a closed position. In the closed position, the flow of fluid between inlet <NUM> and outlet <NUM> of main pneumatic valve <NUM> is blocked by poppet <NUM>. In various embodiments, main pneumatic valve <NUM> may also include a biasing member <NUM> located in upper chamber <NUM>. Biasing member <NUM> is configured to apply a biasing force to poppet <NUM>, thereby forcing poppet <NUM> toward inlet <NUM>.

Referring to <FIG>, during deployment of evacuation slide <NUM>, control valve <NUM> is energized (i.e., current is supplied to control valve <NUM>). In the energized state, control valve <NUM> is closed such that gas, from compressed fluid source <NUM>, flows to inlet <NUM> rather than upper chamber <NUM>. The stoppage of gas flow into upper chamber <NUM> (e.g., by venting the high pressure fluid in the upper chamber <NUM>) along with the increased flow into inlet <NUM> forces poppet <NUM> away from inlet <NUM>. Stated differently, poppet <NUM> translates away from inlet <NUM> in response to the pressure applied to poppet <NUM> by the gas at inlet <NUM> exceeding the pressure in upper chamber <NUM> and the force applied by biasing member <NUM>. Thus, when control valve <NUM> is energized, the gas provided through inlet <NUM> forces main pneumatic valve <NUM> into an open position. In the open position, poppet <NUM> is removed from outlet <NUM>, thereby allowing gas, from compressed fluid source <NUM>, to flow into inlet <NUM> and out outlet <NUM>. Returning to <FIG>, gas flowing out outlet <NUM> is provided to aspirator <NUM> and then inflatable tube <NUM>.

Referring now to <FIG>, a method <NUM> for controlling inflation of an evacuation slide is provided. In describing the various steps of method <NUM>, reference is made to the components of the inflation control system <NUM> described above with reference to <FIG>. In accordance with various embodiments, method <NUM> includes controller <NUM> receiving a signal to begin inflation of the evacuation slide <NUM> (step <NUM>). The signal to inflate the evacuation slide <NUM> may sent to controller <NUM> in response to deployment of evacuation system <NUM> (e.g., in response to exit door <NUM> being opened, a button being depressed, a lever being actuated, etc.).

Controller <NUM> then receives an ambient temperature measurement from temperature sensor <NUM> (step <NUM>) and determines an open-valve time based on the ambient temperature measurement (step <NUM>). As used herein, "open-valve time" refers to the duration of time that the valve module <NUM> (e.g., main pneumatic valve <NUM>) is in the open position, whereby gas may flow from compressed fluid source <NUM> into inflatable tube <NUM>. Controller <NUM> may determine the open-valve time by accessing an open-time versus temperature database <NUM>. The open-time versus temperature database <NUM> includes a library of open-valve times (i.e., the duration of time that control valve <NUM> should be energized) associated with achieving a desired inflation pressure of evacuation slide <NUM> at particular ambient temperatures. For example, at a first ambient temperature, the open-valve time may be a first duration of time (e.g., <NUM> seconds) and at a second ambient temperature that is less than the first ambient temperature, the open-valve time may be a second duration of time that is greater than the first duration of time (e.g., <NUM> seconds).

Controller <NUM> then transmits a control signal to the valve module <NUM> to open the main pneumatic valve <NUM> (step <NUM>). In various embodiments, opening the main pneumatic valve <NUM> is accomplished by energizing, and closing, the normally open control valve <NUM>. Following opening the main pneumatic valve <NUM>, the evacuation slide <NUM> begins to inflate. Controller <NUM> may set, or start, a timer corresponding to the open-valve time simultaneously, or nearly simultaneously, with transmitting the control signal to the valve module <NUM> (step <NUM>). After the main pneumatic valve <NUM> has been open for the open-valve time, controller <NUM> directs valve module <NUM> to close the main pneumatic valve <NUM>, thereby halting the flow of pressurized gas to the inflatable tube <NUM> (step <NUM>). In various embodiments, controller <NUM> directs the main pneumatic valve <NUM> to close in response to expiration of the timer (e.g., in response to the timer reaching zero, or in response to the timer going from zero to the open-valve time). In various embodiments, closing the main pneumatic valve <NUM> is accomplished by de-energizing, and thus opening, control valve <NUM>.

With reference to <FIG>, a ground-test inflation control system <NUM> is illustrated. Ground-test inflation control system <NUM> may be employed to create the open-time versus temperature database <NUM>. In this regard, ground-test inflation control system <NUM> is employed to establish a relationship between the duration of time that main pneumatic valve <NUM> is in the open position and achieving a desired inflation pressure at different test temperatures (i.e., at temperatures likely to be encountered during an inflation process). Ground-test inflation control system <NUM> includes the components of inflation control system <NUM> along with one or more sensor(s) <NUM> configured to monitor the inflation of evacuation slide <NUM>. Sensors <NUM> may be mounted on the inflatable tube <NUM>. In various embodiments, sensors <NUM> may comprise pressure sensors configured to measure a pressure within inflatable tube <NUM>. In various embodiments, sensors <NUM> may comprise stretch sensors configured to monitor an elastic stretch or an elastic deformation of the fabric that forms inflatable tube <NUM> during the inflation process. Real-time data correlating to the ambient temperature measured by temperature sensor <NUM> and real-time data correlating the elastic stretch (or pressure) experienced by the inflatable tube <NUM> may be sent to controller <NUM> during the inflation process.

Based on the ambient temperature data and the elastic stretch (or pressure) data, the duration of time the main pneumatic valve <NUM> needs to be open to achieve the desired inflation pressure at various temperatures may be determined. In this regard, the open-time versus temperature database <NUM> is developed and embedded into the controller <NUM> based on testing performed using ground-test inflation control system <NUM>. The open-time versus temperature database <NUM> will generally include information defining a duration of time the main pneumatic valve <NUM> needs to open to achieve a desired inflation pressure at a given ambient temperature. In other words, the open-time versus temperature database <NUM> will enable the controller <NUM> to determine the open-valve time based on the ambient temperature measurement received from temperature sensor <NUM>.

The inflation control system described above provides several benefits over existing systems. Existing inflation systems, for example, use pressure relief valves assembled to the inflatable. The current design eliminates hard spots on the fabric and potential sources of leakage from the inflatable tube in the regions of the pressure relief valves. Eliminating the pressure relief valves from inflatable also reduces the maintenance requirements. Further, once the open-valve time is achieved, the inflatable tube will have attained the desired pressure, and excess gas flow is halted by the controller at the source of the high-pressure gas (i.e., upstream from the inflatable). Stopping the excess gas flow from the upstream region of the inflatable facilitates increasing the inflatable operating pressure. which can allow for a reduction in tube diameter to achieve the same tube strength. This also enables a reduction in the effective packing volume of the inflatable tube and the quantity of fabric used to construct the inflatable tube.

Claim 1:
An inflation control system for an inflatable, comprising:
a compressed fluid source (<NUM>);
a valve module (<NUM>) connected to the compressed fluid source and configured to control a flow of gas to the inflatable;
a temperature sensor (<NUM>) configured to measure an ambient temperature and output an ambient temperature measurement; and
a controller (<NUM>) operably coupled to the valve module, wherein the controller is configured to receive the ambient temperature measurement and determine an open-valve time based on the ambient temperature measurement, the open-valve time being a duration of time the valve module is in an open position, transmit a first control signal to the valve module to begin the flow of gas to the inflatable, start a timer corresponding to the open-valve time, and transmit a second control signal to halt the flow of gas to the inflatable after expiration of the timer.