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 or 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. Such inflatables are typically stored in an uninflated condition on the structure in a location readily accessible for deployment. For example, an evacuation slide for a commercial aircraft is stored in an uninflated condition in a case or compartment located proximate an emergency exit.

Systems used to inflate evacuation slides typically employ a gas stored within a cylinder or tank at high pressure, which is discharged into the evacuation slide (or into an inflatable tube comprised within the evacuation slide) within a specific time period. This may be accomplished, for example, by opening a main inflation valve that connects the high-pressure gas to the inflatable tube. Since fast inflation times for an evacuation slide or raft are important, most inflation systems will have excess gas in the storage cylinder or tank to ensure complete inflation and to adjust for variations in ambient temperature and gas supply lines. An evacuation slide is also typically provided with one or more pressure relief valves to vent the excess gas after the evacuation slide or inflatable tube is charged to the set pressure of the pressure relief valve.

During an emergency or similar event, the evacuation slide is typically deployed in response to an action taken by a passenger or a crew member. Upon deployment, the high-pressure gas is forced into the evacuation slide or the inflatable tube, causing inflation of the slide to occur. Amount of inflation gas to achieve a desired inflatable pressure varies with ambient temperature. More inflation gas is desired at lower ambient temperatures and less gas desired at higher temperatures due to changes in densities of gasses with variations in temperature. The amount of gas stored in the pressurized cylinder is often based on a worst-case situation. For larger inflatables, additional gas may be stored to account for the variations in aspirator efficiencies. In any case, excess gas flows to inflatable and is typically vented through pressure relief valve (PRV) attached on the inflatable. Evacuation systems are disclosed in <CIT>, <CIT> and <CIT>.

An evacuation system for an aircraft is provided as defined by claim <NUM>.

In various embodiments, the evacuation system may further comprise a compressed fluid source and a solenoid valve, wherein the solenoid valve is disposed fluidly between the compressed fluid source and the inflatable tube, and wherein the solenoid valve is configured to transition from a second closed state to an open state in response to being energized. The solenoid valve may be energized in response to both the pressure switch and the electrical switch being in the closed state. The solenoid valve may be configured to be de-energized in response to the pressure switch being open. The evacuation system may comprise a motor coupled to a compressor via a shaft, wherein the motor is configured to power the compressor in response to the pressure switch and the electrical switch being in the closed state. The evacuation system may further comprise a controller configured to receive a signal from the pressure switch in response to the pressure switch being in the closed state, wherein the controller is configured to command the motor to reduce the power in response to no longer receiving the signal.

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. 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.

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> an inflation control circuit <NUM>. The inflation control circuit <NUM> includes an electrical switch <NUM>, a pressure switch <NUM>, a control valve <NUM>, and a power source <NUM>.

As described further herein, the electrical switch <NUM> transitions from an open position to a closed position in order to imitate inflation of the evacuation slide <NUM>. In various embodiments, the pressure switch <NUM> may modulate between an open position and closed position during inflation of the evacuation slide <NUM> as described further herein. In response to the electrical switch <NUM> and the pressure switch <NUM> both being closed, an electrical circuit is completed between the control valve <NUM> and the power source <NUM>. Thus, the control valve <NUM> may be a nominally closed solenoid valve. In this regard, the control valve <NUM> is configured to open in response to receiving an electrical current from the power source <NUM> due to an electrical circuit being completed as described further herein.

Inflation control system <NUM> further comprises a valve module <NUM>, which includes the control valve <NUM> and a pressure regulator <NUM>, a 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), an aspirator <NUM>, a controller <NUM>, and a power source <NUM>, such as, for example, a battery or charged capacitor. Although illustrated as comprising the controller <NUM> and the power source <NUM>, the present disclosure is not limited in this regard. For example, the electrical switch <NUM> may be activated mechanically (e.g., via actuation of a mechanical trigger configured for activation via moving, pressing, releasing, or touching) or activated electronically (e.g., via a command signal from controller <NUM> powered by power source <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> (e.g., electronically activating electrical switch <NUM> to transition from an open position to a closed position).

In various embodiments, the power source <NUM> is a source configured to power the electrical switch <NUM> only. In this regard, the power source <NUM> may be used to activate (i.e., close via an electronic input) electrical switch <NUM> to initiate an inflation process, in accordance with various embodiments. In various embodiments, the power source <NUM> is a dedicate source of power for the control valve <NUM>. In this regard, in response to switches <NUM>, <NUM> both being closed, the power source <NUM> is in electrical communication with the control valve <NUM>.

To provide a dedicated source of direct current power, the power sources <NUM>, <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>.

In various embodiments, a plumbing system <NUM> comprises fluid conduits <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The fluid conduit <NUM> extends from the compressed fluid source to the valve module <NUM>. Fluid conduit <NUM> extends from the valve module <NUM> to the aspirator <NUM>. Fluid conduit <NUM> extends from the aspirator <NUM> to a fluid junction <NUM> (e.g., a three-way elbow, three-way tee, a three-way Y-fitting, a three-way L-fitting, etc.). Fluid conduit <NUM> extends from the fluid junction <NUM> to the evacuation slide <NUM>, and fluid conduit <NUM> extends from the fluid junction <NUM> to the pressure switch <NUM>. In various embodiments, the mechanical pressure switch is configured to transition from a closed position to an open position in response to being exposed to a pressure that exceeds a pressure threshold. The pressure threshold may be determined based on a pressure profile during inflation as described further herein. In this regard, the pressure switch <NUM> may modulate between an open and closed position during inflation, resulting in opening and closing of the control valve <NUM>, and thus modulating a pressure of the fluid being supplied from the compressed fluid source <NUM>, in accordance with various embodiments.

The pressure switch <NUM> comprises a mechanical pressure switch <NUM>. The mechanical pressure switch <NUM> comprises a pressure sensing element <NUM> in the form of a membrane or a piston and a micro-switch <NUM>. When the pressure reaches, or exceeds the pressure threshold, the micro switch contact snaps open to open the inflation control circuit <NUM>. The mechanical pressure switch <NUM> may be low cost compared to typical inflation control systems, in accordance with various embodiments. The mechanical pressure switch <NUM> may also be reliable and long lasting, in accordance with various embodiments. The mechanical pressure switch <NUM> is configured to passively control a pressure of fluid being dispensed in the evacuation slide <NUM>. In this regard, a pressure relief valve may essentially be eliminated, as well as sensors and/or controllers, in accordance with various embodiments.

In various examples not falling within the scope of the claims, the pressure switch <NUM> may comprise an electronic pressure switch <NUM>. For example, with reference now to <FIG>, the inflation control system <NUM> comprising a pressure switch <NUM> that is an electronic pressure switch <NUM> is illustrated. The electronic pressure switch <NUM> may comprise a controller <NUM>, a memory <NUM>, a pressure sensor <NUM>, and the micro-switch <NUM>.

Controller <NUM> may comprise a microcontroller integrated within the electronic pressure switch <NUM>. The controller <NUM> may comprise a processor. Controller <NUM> may be implemented in a single processor. Controller <NUM> may be implemented as and may include one or more processors and/or one or more tangible, non-transitory memories (e.g., memory <NUM>) and be capable of implementing logic. Each processor can be a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. Controller <NUM> may comprise a processor configured to implement various logical operations in response to execution of instructions, for example, instructions stored on a non-transitory, tangible, computer-readable medium configured to communicate with controller <NUM>.

The controller <NUM> is in electronic (e.g., wireless or wired) communication with the memory <NUM>, the pressure sensor <NUM>, and the micro-switch <NUM>. In this regard, the controller <NUM> may be configured to receive pressure data from the pressure sensor <NUM> and command the micro-switch to transition from a closed position to an open position in response to the pressure data exceeding the pressure threshold described previously herein. A transient time period may exist during inflation where pressure may exceed the pressure threshold. For example, the evacuation slide <NUM> may comprise restraints <NUM> between adjacent inflatable tubes <NUM> configured to break during inflation of the evacuation slide <NUM>. In this regard, pressure in fluid conduit <NUM> prior to breaking of the restraints <NUM> may exceed the desired pressure threshold for the electronic pressure switch <NUM>. In this regard, the controller <NUM> may be configured to maintain the micro-switch <NUM> in a closed position during the transient time period described previously herein to ensure breaking of restraints <NUM> and proper inflation of the evacuation slide <NUM>. Thus, when pressure during inflation exceeding the desired pressure threshold prior to restraints <NUM> breaking, the electronic pressure switch <NUM> may be advantageous. In various embodiments, when pressure during inflation is below the desired pressure threshold, the mechanical pressure switch <NUM> from <FIG> may be advantageous, in accordance with various embodiments.

Although illustrated as utilizing a compressed fluid source <NUM>, the present disclosure is not limited in this regard. For example, with reference now to <FIG>, ambient air may be utilized for inflation of evacuation slide <NUM> via a motor <NUM> and compressor <NUM>, in accordance with various embodiments. In various embodiments, the motor <NUM> may be coupled to the compressor <NUM> via a shaft <NUM>. The compressor <NUM> may comprise a fluid inlet <NUM> configured to receive ambient air from an external source (e.g., external to an aircraft or external to the inflation control system <NUM>.

In various embodiments, the inflation control system <NUM> comprises a controller <NUM>. The controller <NUM> may be in electronic (e.g., wireless or wired) communication with the power source <NUM>, the electrical switch <NUM>, and the pressure switch <NUM>. In various embodiments, in response to the pressure switch <NUM> transitioning from an open state to a closed state during inflation (i.e., while the electrical switch <NUM> is in a closed state), a signal from the pressure switch <NUM> to the controller <NUM> will no longer be received by the controller <NUM>. In response to the controller <NUM> losing the signal from the pressure switch <NUM> transitioning from a closed state to an open state, the controller <NUM> may command the motor to reduce a power output or shut off a power output, in accordance with various embodiments. In this regard, the pressure output to the evacuation slide <NUM> may be controlled, in accordance with various embodiments.

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 a temperature sensor.

The inflation control system described above provides several benefits over existing systems. Pressure switch <NUM> may be reliable with a long operational life (e.g., one million cycles or greater), in accordance with various embodiments. Mechanical pressure switch <NUM> may utilize no electric power during operation. Pressure switch <NUM> is light weight (e.g., <NUM> to <NUM> grams) and may facilitate removal of various components (e.g., sensors, controllers, or the like), in accordance with various embodiments. The inflation control systems disclosed herein may result in a weight reduction compared to typical systems, in accordance with various embodiments.

In various embodiments, the inflation control system disclosed herein may be utilized in various inflation systems which use repeatedly operating electric inflators, such as solenoid valves, pneumatic valves, electric motors, or the like. In various embodiments, the inflation control systems disclosed herein may avoid usage of feedback-controlled inflation systems, sensors, real-time data for controllers, etc. Stretch sensors and mounting joints of typical inflation systems involve higher cost than inflation control systems disclosed herein, in accordance with various embodiments. In various embodiments, the inflation control system disclose herein may improve packing of an inflation device by reducing safety procedures typical of sensors for typical inflation control systems.

The inflation control system <NUM> disclosed herein provides a passively controlled inflation system. In this regard, a complexity of the inflation control system <NUM> may be less than a typical inflation control system.

In various embodiments, the inflation control systems disclosed herein may reduce processing and maintenance efforts due to elimination of feedback controls, long electrical wire routing, or the like associated with typical inflation control systems. In various embodiments, pressure switch <NUM> disclosed herein may be easily replaceable providing enhanced maintenance capability relative to typical inflation control systems.

Benefits and other advantages have been described herein with regard to specific embodiments. However, the benefits, advantages, and any elements that may cause any benefit or advantage to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosure.

Claim 1:
An evacuation system for an aircraft, comprising:
an inflatable tube (<NUM>); and
a control circuit (<NUM>) comprising a power source (<NUM>), a pressure switch (<NUM>), and an electrical switch (<NUM>), the evacuation system configured to inflate the inflatable tube in response to both the pressure switch and the electrical switch being in a closed state, the pressure switch configured to open in response to being exposed to a pressure at or exceeding a pressure threshold, the evacuation system configured to reduce a pressure output to the inflatable tube in response to the pressure switch being open; characterized in that:
the pressure switch is a mechanical pressure switch comprising a micro-switch (<NUM>) and
a pressure sensing element (<NUM>) in the form of a membrane or a piston, and
the mechanical pressure switch is configured to passively control a pressure of a fluid being dispensed in the inflatable device (<NUM>).