Patent Description:
Fire protection sprinkler systems are some of the most widely used devices for fire protection. These systems have sprinklers that are activated once the ambient temperature in an environment, such as a room or building, exceeds a predetermined value. Once activated, the sprinklers distribute fire suppressant fluid, such as water, in the room or building. A sprinkler system is considered effective if it extinguishes or prevents growth of a fire.

Fire protection sprinklers generally include a body with an outlet, an inlet connectable to a source of pressurized fire suppressant fluid under pressure, and a deflector supported by the body in a position opposing the outlet for distribution of the fire retardant fluid over a predetermined area to be protected from fire. Individual fire protection sprinklers may be closed or sealed by a cap. The cap is held in place by a thermally-sensitive element which is released when its temperature is elevated to within a prescribed range, e.g. by the heat from a fire. <CIT> discloses a sprinkler head including a sprinkler body with a passage for fluid and a seal mechanism sealing the passage, and a cage member. <CIT> discloses a temperature-activated valve for a conventional fire sprinkler utilizing a hyperelastic single-crystal shape memory alloy. <CIT> discloses thermally activated devices, including thermally activated release devices.

At least one embodiment relates to a sprinkler for a fire suppression system. The sprinkler includes a body defining an inlet and an outlet fluidly coupled to one another, a frame assembly including a frame member coupled to the body and extending away from the outlet, a deflector coupled to the frame member and offset from the outlet, a seal assembly configured to sealingly engage the body to prevent flow through the outlet, and a trigger assembly. The trigger assembly includes a shape memory alloy element configured to deform from an unactuated configuration to an actuated configuration in response to reaching an activation temperature. In the unactuated configuration, the trigger assembly directly engages both the frame assembly and the seal assembly and holds the seal assembly in sealed engagement with the body. In the actuated configuration, the trigger assembly permits the seal assembly to disengage from the body. The shape memory alloy element is one of a plurality of shape memory alloy elements of the trigger assembly, and the shape memory alloy elements extend substantially parallel to a central axis of the body in the unactuated configuration.

In some embodiments, the trigger assembly includes a collar extending at least partially around the shape memory alloy elements and coupling the shape memory alloy elements to one another in the unactuated configuration.

In some embodiments, the collar is configured to deform when transitioning from the unactuated configuration to the actuated configuration, permitting the shape memory alloy elements to separate from one another.

In some embodiments, the shape memory alloy elements are directly coupled to one another.

In some embodiments, the shape memory alloy elements are directly fixedly coupled to one another at a series of points distributed along the length of each shape memory alloy element.

In some embodiments, not according to the invention, the trigger assembly includes a push rod that is received by an outer tube, and the shape memory alloy element moves the push rod relative to the outer tube when transitioning from the unactuated state to the actuated state to reduce an overall length of the trigger assembly.

In some embodiments, not according to the invention, the shape memory alloy element is a shape memory alloy lever fixedly coupled to the outer tube and supporting the push rod.

In some embodiments, not according to the invention, the shape memory alloy elements extend radially inward from the outer tube.

In some embodiments, not according to the invention, the shape memory alloy levers are integrally formed with the outer tube.

In some embodiments, not according to the invention, the shape memory alloy element is a tubular element having a wall that defines a passage.

In some embodiments, not according to the invention, one or more slots extend through the wall.

In some embodiments, not according to the invention, a slot extends through the wall along the entire length of the tubular element.

In some embodiments, not according to the invention, tubular element unrolls when transitioning from the unactuated state to the actuated state.

Another embodiment relates to a trigger assembly for a sprinkler. The trigger assembly includes a shape memory alloy element configured to deform from an unactuated configuration to an actuated configuration in response to reaching an activation temperature. The trigger assembly has a first end configured to engage a frame assembly of the sprinkler and a second end opposite the first end that is configured to directly engage a seal assembly of the sprinkler. The trigger assembly has a first distance between the first end and the second end in the unactuated configuration and a second distance between the first end and the second end in the actuated configuration. The first distance is greater than the second distance. The shape memory alloy element is one of a plurality of shape memory alloy elements of the trigger assembly, and the shape memory alloy elements extend substantially parallel to one another in the unactuated configuration.

Another embodiment relates to a method of manufacturing a sprinkler. The method includes providing a body defining an inlet and an outlet in fluid communication with one another, the body having a central axis, fixedly coupling a frame member to the body, translatably coupling an adjustment mechanism to the frame member, positioning a seal assembly such that the seal assembly extends across the outlet, inserting a trigger assembly between the adjustment mechanism and the seal assembly, and translating the adjustment mechanism toward the body until a compressive force is applied to the trigger assembly along the central axis by the seal assembly and the adjustment mechanism. The trigger assembly includes a shape memory alloy element configured to deform from an unactuated configuration to an actuated configuration in response to reaching an activation temperature. The compressive force decreases when the trigger assembly transitions from the unactuated configuration to the actuated configuration. The shape memory alloy element is one of a plurality of shape memory alloy elements of the trigger assembly, and the shape memory alloy elements extend substantially parallel to one another in the unactuated configuration.

This summary is illustrative only and is not intended to be in any way limiting.

Other aspects, inventive features, and advantages of the devices or processes described herein will become apparent in the detailed description set forth herein, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements.

Before turning to the figures, which illustrate certain exemplary embodiments in detail, it should be understood that the present disclosure is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology used herein is for the purpose of description only and should not be regarded as limiting.

Some fire sprinkler systems utilize a trigger device, such as a glass bulb or a solder element. Embodiments of the present disclosure utilize Shape Memory Alloy (SMA) to replace the trigger device of a fire sprinkler. The SMA trigger is responsive to a temperature indicative of fire, causing the SMA trigger to deform (change size and/or shape) when exposed to the temperature. In some embodiments, the SMA trigger deforms by varying its length. In some embodiments, the SMA trigger deforms to a C-shape. Upon deforming, the SMA trigger releases a seal assembly, allowing water to discharge through the fire sprinkler.

Fire suppression sprinklers generally include a body with an outlet, an inlet connectable to a source of fire retardant fluid or fire suppressant fluid under pressure, and a deflector supported by the body in a position opposing the outlet for distribution of the fire-extinguishing fluid over a predetermined area to be protected from fire. Individual fire suppression sprinklers may be closed or sealed by a cap. The cap is held in place by a thermally-sensitive element which is released when its temperature is elevated to within a prescribed range (e.g. by the heat from a fire).

Referring to <FIG>, a fire suppression system <NUM> for a building or other space is shown according to an exemplary embodiment. The fire suppression system <NUM> includes a series of sprinklers <NUM> fluidly coupled to a source <NUM> of fire suppressant fluid, such as water. The source <NUM> can include a pump that pressurizes the fire suppressant fluid, a reservoir filled with fire suppressant fluid and positioned atop the building, or another source of pressurized fire suppressant fluid. The sprinklers <NUM> are fluidly coupled to the source <NUM> through one or more conduits <NUM> (e.g., pipes, hoses, etc.). A room <NUM> of the building can utilize one or more sprinklers <NUM>. In some embodiments, the sprinklers <NUM> and/or the conduits <NUM> extend above a ceiling <NUM> of the room <NUM> such that the sprinklers <NUM> and/or the conduits <NUM> are obscured from view. Additionally or alternatively, the sprinklers <NUM> may extend into a wall <NUM> such that the sprinklers <NUM> and/or conduits <NUM> are obscured from view. In other embodiments, the sprinklers <NUM> and/or the conduits <NUM> are not obscured from view. In the event that a fire occurs within the room <NUM>, the ambient temperature around the sprinklers <NUM> increases. Once the temperature increases above a threshold temperature, the sprinklers <NUM> activate, spreading the fire suppressant fluid throughout the room <NUM> to contain and/or extinguish the fire.

Referring to <FIG>, a fire sprinkler assembly, shown as sprinkler <NUM>, is shown according to an exemplary embodiment. The sprinkler <NUM> is intended to be illustrative of one non-limiting example embodiment. The sprinkler <NUM> is shown to include a sprinkler frame, shown as frame assembly <NUM>, coupled to a main body, shown as body <NUM>, both of which are substantially centered about a central axis CA of the sprinkler <NUM>. The frame assembly <NUM> includes a support structure, shown as frame <NUM>, fixedly coupled (e.g., integrally formed with) the body <NUM>. As shown, the frame <NUM> is generally arc-shaped and oriented such that the center of the arc extends away from the body <NUM>. The frame assembly <NUM> may include any number of arms or structural features. The frame assembly <NUM> further includes a fluid deflecting structure, shown as deflector <NUM>, fixedly coupled to the frame <NUM>. The deflector <NUM> is offset from the body <NUM> and substantially centered about the central axis CA.

The frame assembly <NUM> further includes an adjustment device (e.g., a screw, a slider, etc.) shown as setscrew <NUM>, that is substantially centered about the central axis CA. The frame <NUM> and the deflector <NUM> define an aperture configured to receive the setscrew <NUM>. The aperture is threaded such that the setscrew <NUM> translates along the central axis CA when rotated. During assembly and maintenance of the sprinkler <NUM>, the setscrew <NUM> may be rotated to adjust a position of the setscrew <NUM> along the central axis CA, moving the setscrew <NUM> closer to or farther from the body <NUM>.

The body <NUM> defines an internal passageway (e.g., a passage) extending from an inlet <NUM> to an outlet <NUM>. In some embodiments, the inlet <NUM> and the outlet <NUM> are substantially centered about the central axis CA. The inlet <NUM> is fluidly coupled to a source of fire suppressant fluid (e.g., the conduit <NUM>) and facilitates flowing fluid through the body <NUM>. As shown in <FIG>, the body <NUM> includes a threaded portion <NUM> that facilitates coupling the sprinkler <NUM> to the conduit <NUM>. In an unactuated configuration of the sprinkler <NUM>, a seal assembly <NUM> extends across the outlet <NUM>, sealing the passageway and preventing the flow of fluid out of the sprinkler <NUM>. The seal assembly <NUM> includes a sealing body (e.g., a plug, an adapter, etc.), shown as button <NUM>. An annular sealing member or element (e.g., a frustoconical spring, a Belleville washer, etc.), shown in <FIG> as seal <NUM>, is positioned between the button <NUM> and the body <NUM> and compressed to form a seal.

A trigger assembly (e.g., a prop, a rod, a spacer, a tube, a column, etc.), shown as shape memory alloy (SMA) trigger 130A, is shown in an unactuated configuration or state (e.g., a nominal state, a predeformation state, a holding state, a sealing state, etc.). The SMA trigger 130A extends directly between and directly engages the setscrew <NUM> and the button <NUM>. The setscrew <NUM> and the button <NUM> engage opposing ends of the SMA trigger 130A. As shown, the SMA trigger <NUM> is substantially centered about and axially aligned with the central axis CA. During installation of the SMA trigger <NUM> into the sprinkler <NUM>, the setscrew <NUM> is tightened, imparting a compressive loading onto the SMA trigger <NUM> substantially aligned with the central axis CA. The SMA trigger <NUM> in turn imparts a corresponding loading on the button <NUM>, compressing the seal <NUM> between the button <NUM> and the body <NUM>. In some embodiments, the compressive force supported by the SMA trigger <NUM> is approximately <NUM> pounds (<NUM> N).

In an unactuated configuration, the SMA trigger 130A provides a sufficient opposing force to act against the seal assembly <NUM> preventing fluid or liquid from exiting the outlet <NUM>. If the opposing force to the seal assembly <NUM> is removed (e.g., if the SMA trigger 130A deforms), the sprinkler <NUM> enters an actuated configuration or state (e.g., an activated state, a flowing state, an open state, a suppressing state, etc.), and fluid from the outlet <NUM> flows toward the deflector <NUM>. The deflector <NUM> spreads the spray of the fluid out laterally, and the fluid suppresses fires in the room <NUM>. In the actuated configuration, the SMA trigger 130A may deform (e.g., shrink and/or bend) to change size and/or shape, for example to the shape of the SMA trigger 130B. In some embodiments, the SMA trigger 130A bends (e.g., to a C-shape, to an S-shape). In this regard, deforming to a C-shape may improve reliability, for example of removing the opposing force of the SMA trigger <NUM> to the seal assembly <NUM> and/or to permit the seal assembly <NUM> to disengage from the sprinkler <NUM>. In other embodiments, the SMA trigger 130A shrinks to a shorter overall length (e.g., as measured between the point of contact between the SMA trigger 130A and the setscrew <NUM> and the point of contact between the SMA trigger <NUM> and the button <NUM>). In yet other embodiments, the SMA trigger 130A both bends and shrinks to a shorter overall length.

<FIG> and <FIG> illustrate a sprinkler <NUM> and a sprinkler <NUM>, respectively, that utilize the SMA trigger <NUM>. The sprinkler <NUM> and the sprinkler <NUM> may be substantially similar to the sprinkler <NUM> except as otherwise stated herein. The sprinkler <NUM> includes a biasing element, shown as ejection spring <NUM>. The ejection spring <NUM> extends around a rear side of the SMA trigger <NUM> and along a front side of the frame assembly <NUM>. The ejection spring <NUM> is configured to impart a lateral (e.g., perpendicular to the central axis CA) force on the SMA trigger <NUM>. In the unactuated configuration, the compressive force on the SMA trigger <NUM> is enough to overcome this lateral force and hold the SMA trigger <NUM> in place. When the SMA trigger <NUM> begins to deform, the compressive force on the SMA trigger <NUM> lessens, and the ejection spring <NUM> forces the SMA trigger <NUM> away from the setscrew <NUM> and/or the button <NUM>. This prevents fluid pressure on the button <NUM> from holding the SMA trigger <NUM> in place and facilitates complete activation of the sprinkler <NUM>. The ejection spring <NUM> may be used in any of the sprinklers described herein. In some embodiments, off-axis trigger assemblies are utilized. As shown in <FIG>, the sprinkler <NUM> includes an off-axis trigger assembly including a strut <NUM> that is not parallel with the central axis CA and a lever <NUM> that extends between the strut <NUM> and the setscrew <NUM>.

Embodiments of the present disclosure include an SMA trigger configured to activate a fire sprinkler assembly upon reaching a threshold or activation temperature. As used herein, the terminology "shape memory alloy" (often abbreviated as "SMA") refers to alloys which exhibit a shape memory effect. An SMA may undergo a solid state, crystallographic phase change to shift between a martensite phase, i.e., "martensite," and an austenite phase, i.e., "austenite. " Alternatively stated, an SMA may undergo a displacive transformation rather than a diffusional transformation to shift between martensite and austenite. A displacive transformation is a structural change that occurs by the coordinated movement of atoms (or groups of atoms) relative to their neighbors.

The SMA trigger <NUM> may be of any suitable SMA composition. In an example embodiment, the SMA trigger <NUM> uses a combination of nickel and titanium with a small additive of aluminum. The SMA trigger <NUM> may include an element selected from the group including, without limitation: cobalt, nickel, titanium, indium, manganese, iron, palladium, zinc, copper, silver, gold, cadmium, tin, silicon, platinum, gallium, and combinations thereof. For example, and without limitation, suitable shape memory alloys may include nickel-titanium based alloys, nickel-aluminum based alloys, nickel-gallium based alloys, indium-titanium based alloys, indium-cadmium based alloys, nickel-cobalt-aluminum based alloys, nickel-manganese-gallium based alloys, copper based alloys (e.g., copper-zinc alloys, copper-aluminum alloys, copper-gold alloys, and copper-tin alloys), gold-cadmium based alloys, silver-cadmium based alloys, manganese-copper based alloys, iron-platinum based alloys, iron-palladium based alloys, and combinations thereof. The SMA trigger <NUM> may have components with binary, ternary, or any higher order so long as the shape memory alloy material exhibits a shape memory effect (i.e., a change in shape orientation, damping capacity, etc.).

In some embodiments, when an SMA trigger of a fire sprinkler is exposed to a temperature indicative of a fire, the SMA trigger may begin to deform from an unactuated shape to an actuated shape. In the unactuated shape, the SMA trigger provides a sufficient opposing force to act against a seal assembly preventing fluid or liquid from exiting an outlet of the fire sprinkler. The actuated shape may correspond to a C-shape and/or a smaller size relative to the unactuated shape. In some embodiments, when the SMA trigger deforms to the actuated shape, a screw disengages from the SMA trigger. The SMA trigger disengages from the seal assembly, thereby removing the opposing force acting against the seal assembly. The fluid or liquid is permitted to flow through the body of the fire sprinkler and discharge from the outlet to a deflecting structure. The SMA trigger <NUM> shown in <FIG> is intended to be a generic example of an SMA trigger. Accordingly, the SMA trigger <NUM> shown in <FIG> may represent any of the embodiments described herein.

The SMA trigger <NUM> may include one or more SMA components and one or more non-SMA components (e.g., components that deform minimally in response to a variation in temperature). Referring to <FIG>, a model <NUM> illustrates an exemplary loading of an SMA element <NUM> of the SMA trigger <NUM>. The SMA element <NUM> includes (e.g., is made entirely from) SMA material. This loading arrangement may represent the loading that the SMA element <NUM> experiences within the sprinkler <NUM> or any of the other sprinklers shown herein. In <FIG>, the SMA trigger <NUM> (and thus the SMA element <NUM>) is arranged in the unactuated configuration. In the unactuated configuration, the SMA element <NUM> is arranged substantially vertically. A first end of the SMA element <NUM> engages a first fixturing element, block, or receiver (e.g., representing the setscrew <NUM>), shown as fixed block <NUM>, that is fixed in space. A second end of the SMA element <NUM> engages a second fixturing element, block, or receiver (e.g., representing the seal assembly <NUM>), shown as translating block <NUM>, that is permitted to translate freely vertically. As shown, the ends of the SMA element <NUM> are rounded (e.g., semispherical, domed, etc.), and the fixed block <NUM> and the translating block <NUM> each define correspondingly-shaped recesses <NUM> that receive the ends. This arrangement permits rotation of the SMA element <NUM> relative to the fixed block <NUM> and the translating block <NUM>.

A load, shown as weight W, is applied downward on the SMA element <NUM> through the translating block <NUM>. The weight W may represent the force that the SMA trigger <NUM> experiences in the unactuated configuration (e.g., the combination of the force required to compress the seal assembly <NUM> and the force required to resist the pressurized fluid acting on the seal assembly <NUM>). In some embodiments, the weight W is approximately <NUM> pounds (<NUM> N).

In the unactuated configuration, the SMA element <NUM> may be configured to support the weight W over an extended period of time (e.g., <NUM> years) without deforming. As shown, the SMA element <NUM> is a rod having a diameter D<NUM> and an overall length D<NUM> measured as the vertical distance between the top and bottommost points of the SMA element <NUM>. In an embodiment that includes only a single, solid SMA element <NUM> (e.g., the SMA element <NUM>), the diameter D<NUM> may be approximately <NUM>-<NUM> and the overall length D<NUM> may be approximately <NUM>.

In response to reaching or exceeding a transition temperature, operating temperature, activation temperature, or threshold temperature, the SMA element <NUM> is configured to deform to the actuated configuration. The SMA element <NUM> may reach the transition temperature in response to an ambient temperature of the surrounding fluid (e.g., air) reaching or exceeding the operating temperature. At temperatures below the operating temperature, the SMA element <NUM> may experience very little or no deflection. The SMA element <NUM> may deform to the actuated configuration quickly upon reaching the operating temperature. By way of example, the SMA element may have less than a <NUM> second transition time when moved from a room temperature environment to an environment at the operating temperature. After changing to the actuated configuration, the SMA element <NUM> may or may not be capable of transitioning back to the unactuated configuration. Instead, the SMA element <NUM> may be discarded and/or replaced after the sprinkler <NUM> is activated.

Referring to <FIG>, the SMA element <NUM> is shown in the actuated configuration. In these embodiments, the SMA element <NUM> is trained (e.g., manufactured, configured, etc.) to decrease the overall length D<NUM> by bending in response to reaching the operating temperature. This is facilitated by the corresponding rounded shapes of the ends of the SMA element <NUM>, and the recesses of the fixed block <NUM> and the translating block <NUM>. As shown in <FIG>, the SMA element <NUM> is configured to bend about two bend axes <NUM>. As shown in <FIG>, the SMA element <NUM> is configured to bend about a single bend axis <NUM>. In other embodiments, the SMA element <NUM> is configured to bend about more than two bend axes. Another bending deformation is shown in <FIG>. In this embodiment, the SMA trigger <NUM> forms a C shape. In some embodiments, SMA formulations such as Nitinol are used to achieve a bending deformation.

Referring to <FIG>, the SMA element <NUM> is configured to contract in response to reaching the operating temperature. Specifically, the SMA element <NUM> deforms such that the length of the SMA element <NUM> decreases parallel to a central axis A<NUM> of the SMA element <NUM>. <FIG> shows the SMA element <NUM> in the unactuated configuration, and <FIG> shows the SMA element <NUM> in the actuated configuration. The overall length D<NUM> of the SMA element <NUM> is greater in the unactuated configuration than in the actuated configuration. In some embodiments, the overall length D<NUM> is reduced by up to <NUM>-<NUM>%. In some embodiments, the overall length D<NUM> is reduced by up to <NUM>%. In some embodiments, material formulations such as Flexinol may be utilized to achieve a contracting deformation. Any of the SMA triggers described herein may include SMA elements that utilize bending deformation, contracting deformation, or some combination thereof.

The specific shape memory alloy material used in the trigger assembly <NUM> may be selected according to a desired operating temperature of the sprinkler <NUM>. In response to the SMA trigger <NUM> meeting or exceeding the operating temperature, part or all of the SMA trigger <NUM> is configured to deform, changing from the unactuated shape, state, or configuration to the actuated shape, state, or configuration. In some embodiments, the desired operating temperature corresponds to a temperature indicative of fire. In some embodiments, the desired operating temperature corresponds to a temperature selected between the range <NUM> (<NUM>°F) through <NUM> (<NUM>°F), or within the temperature ranges as specified in Table <NUM>. <NUM> of NFPA-<NUM>-<NUM>. In some embodiments, the SMA trigger <NUM> holds its basic shape (unactuated shape) prior to reaching the operating temperature.

In some embodiments, the SMA trigger <NUM> has one or more unactuated and/or actuated characteristics, corresponding to one or more physical dimensions or properties. For example, the SMA trigger <NUM> may be or include a material causing the SMA trigger <NUM> to deform within a time period, such as <NUM> seconds or less, upon reaching the actuation temperature. In some embodiments, the SMA trigger <NUM> additionally shrinks by at least <NUM> or more near the actuation temperature. In some embodiments, the SMA trigger <NUM> the actuated shape is curved and the non-actuated shape is straight or substantially straight. In some embodiments, the SMA trigger <NUM> is between <NUM> - <NUM> diameter and <NUM> -<NUM> long at the unactuated temperature. In some embodiments, the SMA trigger <NUM> is between <NUM> - <NUM> diameter and at least <NUM> long at the unactuated temperature. In some embodiments, the ends of the SMA trigger <NUM> may be blunted or have a smaller radius than a center portion.

Referring to <FIG>, a sprinkler <NUM> is shown according to an exemplary embodiment. The sprinkler <NUM> may be substantially similar to the sprinkler <NUM> except as described herein. In this embodiment, the SMA trigger <NUM> is an SMA element <NUM>. The SMA element <NUM> is a single, solid piece of SMA material. The SMA element <NUM> may have a circular, square, rectangular, triangular, hexagonal, or another shape of cross section. In the unactuated state, the SMA element <NUM> is substantially straight and aligned with the central axis CA. In the actuated state, the SMA element <NUM> may experience bending deformation, contracting deformation, or some combination thereof. This deformation reduces the overall length of the SMA element <NUM>, reducing the compressive force on the SMA element <NUM>. This reduction in force may sufficient to permit the seal assembly <NUM> to be released. In some embodiments, the sprinkler <NUM> includes an ejection spring <NUM> that facilitates disengagement of the SMA element <NUM>.

Referring to <FIG>, in the sprinkler <NUM>, the adjustment device <NUM> is an adjustment device <NUM>. The adjustment device <NUM> has a protrusion <NUM> having a conical shape that is centered about the central axis CA. A portion of the adjustment device <NUM> may be threaded to permit adjustment of the position of the protrusion <NUM> along the central axis CA. The protrusion <NUM> is received within an aperture or recess <NUM> defined by a top end portion of the SMA element <NUM> (e.g., the top end portion as shown in <FIG>). Due to the conical shape of the conical protrusion <NUM>, the conical protrusion <NUM> centers the top end of the SMA element <NUM> about the adjustment device <NUM>. In other embodiments, the protrusion <NUM> has a rounded (e.g., dome) shape. In some embodiments, the button <NUM> and the bottom end of the SMA element define corresponding flat surfaces (e.g., extending perpendicular to the central axis CA) that engage one another.

In other embodiments, the frame assembly <NUM> and/or the adjustment device <NUM> and the ends of the SMA element <NUM> define corresponding flat surfaces (e.g., extending perpendicular to the central axis CA) that engage one another. In other embodiments, a protrusion <NUM> extends from the seal assembly <NUM> (e.g., from the button <NUM>) and is received by an aperture or recess <NUM> defined by the bottom end of the SMA element <NUM>.

Referring to <FIG>, the SMA trigger <NUM> is an SMA trigger <NUM>. The SMA trigger <NUM> includes an SMA element <NUM> coupled to a pair of interface members, shown as end caps <NUM>. The SMA element <NUM> may be a single, solid piece of SMA material. Alternatively, the SMA element <NUM> may have one or more apertures extending therethrough. The SMA element <NUM> may have a circular, square, rectangular, triangular, hexagonal, or another shape of cross section. Each end cap <NUM> includes a collar portion <NUM> that defines an aperture or recess <NUM> configured to receive an end of the SMA element <NUM>. The collar portion <NUM> at least partially surrounds the SMA element <NUM>. Each end cap <NUM> also defines a rounded surface, shown as engagement surface <NUM>. The engagement surface <NUM> may be domed, spherical, conical, or otherwise curved.

Referring to <FIG> and <FIG>, the button <NUM> defines an aperture <NUM> that leads to a recess <NUM>, both of which are substantially centered about the central axis CA. The engagement surface <NUM> engages at least a portion of the perimeter of the aperture <NUM>, holding the SMA trigger <NUM> in place. The end cap <NUM> extends at least partially into the recess <NUM>. Specifically, the end cap <NUM> extends a distance X into the recess <NUM>. The distance X may be varied by adjusting the size of the aperture <NUM> and/or the radius of curvature of the engagement surface <NUM>. The rounded shape of the engagement surface <NUM> centers the end cap <NUM> about the central axis CA. Similarly, the frame assembly <NUM> and/or the adjustment device <NUM> may define an aperture <NUM> and a recess <NUM> that receive the other end cap <NUM>.

In the unactuated state, the SMA element <NUM> is substantially straight and aligned with the central axis CA. In the actuated state, the SMA element <NUM> may experience bending deformation, contracting deformation, or some combination thereof. This deformation reduces the overall length of the SMA element <NUM>, reducing the compressive force on the SMA element <NUM>. This reduction in force may sufficient to permit the seal assembly <NUM> to be released, particularly if the SMA element <NUM> bends during the deformation (e.g., into a C shape). The rounded shapes of the engagement surfaces <NUM> may facilitate rotation of the end caps <NUM> relative to the frame assembly <NUM> and/or the seal assembly <NUM>.

In some embodiments, the sprinkler <NUM> includes an ejection spring <NUM> that facilitates disengagement of the SMA trigger <NUM>. An ejection spring <NUM> may be particularly useful in embodiments where the SMA element <NUM> experiences purely contracting deformation. During activation, the ejection spring <NUM> may apply a lateral biasing force to force the end cap <NUM> out of the recess <NUM>. The magnitude of the lateral force required to remove the end cap <NUM> from the recess <NUM> may be dependent on the distance X and the compressive force on the SMA trigger <NUM>.

Referring to <FIG>, an SMA trigger <NUM> is shown according to an embodiment according to the invention. The SMA trigger <NUM> may be substantially similar to the SMA trigger <NUM> except as otherwise described herein. The SMA trigger <NUM> includes a series of SMA elements <NUM> that are arranged together to form a bundle <NUM>. Although the SMA trigger <NUM> of <FIG> is shown with a given quantity of SMA elements <NUM>, it should be understood that the bundle <NUM> may include more or fewer SMA elements <NUM>. In the unactuated state, the SMA elements <NUM> all extend substantially parallel to the central axis CA and to one another. As shown, each SMA element <NUM> has a substantially circular cross section. In other embodiments, the SMA elements <NUM> have other cross-sectional shapes. As shown, each SMA element <NUM> is approximately the same length. In other embodiments, the lengths of the SMA elements <NUM> vary. In some embodiments, each SMA element <NUM> has a diameter of approximately <NUM> - <NUM> in (<NUM> - <NUM>), and the bundle <NUM> has an overall diameter of approximately <NUM> - <NUM>. The use of multiple smaller SMA elements <NUM> as opposed to one large SMA element may facilitate airflow between the individual SMA elements <NUM> and reduce the ratio of SMA element mass to SMA surface area. This may reduce the transition time required to activate the SMA trigger <NUM>, permitting the sprinkler <NUM> to respond to a fire more quickly.

The SMA trigger <NUM> further includes a pair of end caps <NUM>. Each end cap <NUM> includes a collar portion <NUM> that defines an aperture or recess <NUM> configured to receive an end of the bundle <NUM>. In some embodiments, the recess <NUM> is tapered to facilitate a secure friction fit of the bundle <NUM> within the end cap <NUM>. Additionally or alternatively, adhesive may be used to couple the bundle <NUM> to the end cap <NUM>. The collar portion <NUM> at least partially surrounds the bundle <NUM>. The collar portion <NUM> may prevent the SMA elements <NUM> from separating from one another and retain the SMA elements <NUM> in a desired orientation (e.g., parallel to one another) in the unactuated configuration. Each end cap <NUM> also defines a rounded surface, shown as engagement surface <NUM>. The engagement surface <NUM> may engage the seal assembly <NUM> and/or the frame assembly <NUM> similarly to the engagement surface <NUM>.

Referring to <FIG>, the SMA trigger <NUM> is shown according to an alternative embodiment according to the invention. In this embodiment, the end caps <NUM> are omitted, and the shape of the bundle <NUM> is maintained in the unactuated configuration by a series of annular retaining members or collars, shown as rings <NUM>. As shown in <FIG>, the SMA trigger <NUM> includes three rings <NUM> evenly spaced along the length of the bundle <NUM>. The rings <NUM> may be fixedly or slidably coupled to the bundle <NUM>. In the unactuated configuration, the rings <NUM> hold the SMA elements <NUM> in a desired orientation. In some embodiments, in the actuated configuration, the SMA elements <NUM> experience bending or contracting deformation to facilitate activation of the sprinkler <NUM>.

In some embodiments, the rings <NUM> are made from a material that is configured to deform (e.g., bend, melt, etc.) at the operation temperature, permitting the SMA elements <NUM> to move apart from one another. By way of example, the rings <NUM> may be made from a solder that melts at the operation temperature. By way of another example, the rings <NUM> may be made from an SMA material that deforms from an annular shape to a straight shape at the operation temperature. Once the SMA elements <NUM> move apart from one another, the bundle <NUM> may no longer hold the compressive force, and the seal assembly <NUM> may be free to exit the sprinkler <NUM>. Accordingly, in some embodiments, the SMA elements <NUM> are replaced with similarly shaped and sized elements made from a non-SMA material.

In some embodiments, the rings <NUM> of <FIG> are used in combination with the end caps <NUM> of <FIG>. The inclusion of the rings <NUM> may facilitate holding the SMA elements <NUM> in place. This strengthening of the bundle <NUM> may facilitate the use of smaller diameter SMA elements <NUM>, resulting in a shorter transition time. Referring to <FIG>, additionally or alternatively, the SMA elements <NUM> may be directly coupled to one another. In some embodiments, the SMA elements <NUM> are welded (e.g., laser welded) to one another. Specifically, the SMA elements <NUM> are fixedly coupled to one another at points, shown as tack welds <NUM>. The tack welds are spaced long the length of each SMA element <NUM>. <FIG> show the bundle <NUM> in the unactuated configuration. The use of tack welds <NUM> spaced apart from one another as opposed to a continuous weld along the length of each SMA element may facilitate bending of the SMA elements <NUM> when the SMA trigger <NUM> transitions to the actuated configuration (e.g., as shown in <FIG>).

Referring to <FIG> and <FIG>, the SMA trigger <NUM> is an SMA trigger <NUM>. The SMA trigger <NUM> includes a first member, shown as outer tube <NUM>, and a second member, shown as push rod <NUM>, that is received within a central passage <NUM> of the outer tube <NUM>. A series of protrusions, shown as SMA levers <NUM>, are coupled to the outer tube <NUM> and extend radially inward (e.g., toward the central axis CA) and upward from outer tube <NUM>. The push rod <NUM> rests atop and is supported by the ends of the SMA levers <NUM>. The top end of the push rod <NUM> may engage the frame assembly <NUM>, and the bottom end of the outer tube <NUM> may engage the seal assembly <NUM> in the unactuated configuration of the sprinkler <NUM>. Alternatively, the top end of the push rod <NUM> may engage the seal assembly <NUM>, and the bottom end of the outer tube <NUM> may engage the frame assembly <NUM> in the unactuated configuration of the sprinkler <NUM>.

Referring to <FIG>, when transitioning from the unactuated configuration to the actuated configuration, the SMA levers <NUM> rotate downward, reducing the overall length D<NUM> of the SMA trigger <NUM>. Specifically, as shown in <FIG>, the ends of the SMA levers <NUM> move a distance Δd downward. Accordingly, the push rod <NUM> also moves the distance Δd downward, reducing the overall length D<NUM> by the distance Δd. This change in length permits the seal assembly <NUM> to move away from the body <NUM> and activate the sprinkler <NUM>.

Referring to <FIG>, in some embodiments, the SMA levers <NUM> may be formed from the outer tube <NUM>. As shown in <FIG>, the SMA levers <NUM> may be cut (e.g., laser cut) from the outer tube <NUM>. As shown in <FIG>, the SMA levers <NUM> may be bent inward. In other embodiments, the outer tube <NUM> and the SMA levers <NUM> are formed as separate pieces and coupled (e.g., welded, adhered, etc.) to one another. The SMA levers <NUM> each have a length L measured vertically and a width W measured horizontally. In some embodiments, the length L is much greater than the width W to facilitate buckling of the SMA levers <NUM> during activation of the sprinkler <NUM>.

Referring to <FIG>, the sprinkler <NUM> is shown according to an alternative embodiment. In this embodiment, the SMA element <NUM> is omitted, and the SMA trigger <NUM> is an SMA element <NUM>. As shown in <FIG>, in the unactuated configuration, the SMA element <NUM> includes a wall <NUM> that is substantially cylindrical. The wall <NUM> defines a passage <NUM> extending through the center of the SMA element <NUM>. The wall <NUM> further defines a slot or groove <NUM> extending through the wall <NUM> along the entire length of the SMA element <NUM>. The passage <NUM> receives the protrusion <NUM> of the adjustment device <NUM> to align the SMA element <NUM> with the central axis CA.

In some embodiments, when transitioning to the actuated configuration, the SMA element <NUM> experiences bending or contraction deformation (e.g., similar to the SMA element <NUM>). In some embodiments, when transitioning to the actuated configuration, the wall <NUM> of the SMA element <NUM> unrolls. In some embodiments, as shown in <FIG>, the wall <NUM> unrolls to the point where the wall <NUM> forms a flat sheet. As the SMA element <NUM> deforms, the compressive force on the SMA element <NUM> lessens, and the seal assembly <NUM> is permitted to move away from the body <NUM>.

Referring to <FIG>, a modification to the SMA element <NUM> is shown, according to an exemplary embodiment. In this embodiment, a series of apertures, slots, slits, or cutouts, shown as vertical slits <NUM>, are defined in the wall <NUM>. The vertical slits <NUM> extend substantially vertically. Specifically, a height of each vertical slit <NUM> measured parallel to the central axis CA is much larger than a width of each vertical slit <NUM> measured perpendicular to the central axis CA. In the unactuated configuration, the SMA element <NUM> of <FIG> supports the load of the seal assembly <NUM> similarly to the SMA element <NUM> of <FIG>. When transitioning to the actuated configuration, vertical sections <NUM> of the wall <NUM> positioned between the vertical slits <NUM> buckle, moving perpendicular to the central axis CA, and decreasing the overall length of the SMA element <NUM>.

Referring to <FIG>, a modification to the SMA element <NUM> is shown, according to another exemplary embodiment. In this embodiment, a series of apertures, slots, slits, or cutouts, shown as horizontal slits <NUM>, are defined in the wall <NUM>. The horizontal slits <NUM> extend substantially horizontally. Specifically, a height of each horizontal slit <NUM> measured parallel to the central axis CA is much smaller than a width of each horizontal slit <NUM> measured perpendicular to the central axis CA. In the unactuated configuration, the SMA element <NUM> of <FIG> supports the load of the seal assembly <NUM> similarly to the SMA element <NUM> of <FIG>. When transitioning to the actuated configuration, sections <NUM> of the wall <NUM> positioned adjacent the horizontal slits <NUM> buckle, moving perpendicular to the central axis CA, and decreasing the overall length of the SMA element <NUM>.

As utilized herein, the terms "approximately," "about," "substantially," and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims.

The term "coupled" and variations thereof, as used herein, means the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent or fixed) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members coupled directly to each other, with the two members coupled to each other using a separate intervening member and any additional intermediate members coupled with one another, or with the two members coupled to each other using an intervening member that is integrally formed as a single unitary body with one of the two members. If "coupled" or variations thereof are modified by an additional term (e.g., directly coupled), the generic definition of "coupled" provided above is modified by the plain language meaning of the additional term (e.g., "directly coupled" means the joining of two members without any separate intervening member), resulting in a narrower definition than the generic definition of "coupled" provided above. Such coupling may be mechanical, electrical, or fluidic.

The term "or," as used herein, is used in its inclusive sense (and not in its exclusive sense) so that when used to connect a list of elements, the term "or" means one, some, or all of the elements in the list. Conjunctive language such as the phrase "at least one of X, Y, and Z," unless specifically stated otherwise, is understood to convey that an element may be either X, Y, Z; X and Y; X and Z; Y and Z; or X, Y, and Z (i.e., any combination of X, Y, and Z). Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of X, at least one of Y, and at least one of Z to each be present, unless otherwise indicated.

Although the figures and description may illustrate a specific order of method steps, the order of such steps may differ from what is depicted and described, unless specified differently above. Also, two or more steps may be performed concurrently or with partial concurrence, unless specified differently above. Such variation may depend, for example, on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations of the described methods could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps, and decision steps.

Claim 1:
A sprinkler (<NUM>) for a fire suppression system, comprising:
a body (<NUM>) defining an inlet (<NUM>) and an outlet (<NUM>) fluidly coupled to the inlet (<NUM>);
a frame assembly (<NUM>) including a frame member (<NUM>) coupled to the body (<NUM>) and extending away from the outlet (<NUM>);
a deflector (<NUM>) coupled to the frame member (<NUM>) and offset from the outlet (<NUM>);
a seal assembly (<NUM>) configured to sealingly engage the body (<NUM>) to prevent flow through the outlet (<NUM>); and
a trigger assembly including a shape memory alloy element configured to deform from an unactuated configuration to an actuated configuration in response to reaching an activation temperature,
wherein in the unactuated configuration, the trigger assembly (<NUM>) directly engages both the frame assembly (<NUM>) and the seal assembly (<NUM>) and holds the seal assembly (<NUM>) in sealed engagement with the body (<NUM>); and
wherein in the actuated configuration, the trigger assembly (<NUM>) enables the seal assembly (<NUM>) to disengage from the body (<NUM>),
characterized in that the shape memory alloy element is one of a plurality of shape memory alloy elements of the trigger assembly (<NUM>), and wherein the shape memory alloy elements extend substantially parallel to a central axis (CA) of the body (<NUM>) in the unactuated configuration.