FRANGIBLE SHAPE MEMORY ALLOY FIRE SPRINKLER VALVE ACTUATOR
First Claim
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1. A thermally-activated sprinkler valve assembly comprising:
- a fluid passageway having an outlet and configured to connect to a source of pressurized fluid;
a valve over the outlet, the valve configured to releasably oppose the force of the pressurized fluid; and
a temperature-sensitive actuator coupled to the valve, the actuator comprising;
a frangible bolt; and
a shape-memory element capable of elongating at a pre-determined stress and temperature, wherein the frangible bolt applies compressive force to the shape-memory element;
wherein the temperature-sensitive actuator is configured to actuate the valve by breaking the frangible bolt when the temperature of the shape-memory element reaches or exceeds the pre-determined temperature.
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Abstract
A temperature-activated valve for a conventional fire sprinkler utilizing a hyperelastic single-crystal shape memory alloy is described. The shape-memory element expands as it is heated, forcing a bolt to break, thereby opening the sprinkler valve. The devices described are less susceptible to accidental breakage than conventional actuators, and have fewer moving parts. Transition temperature of the shape memory alloy can be tuned to a narrow range.
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Citations
31 Claims
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1. A thermally-activated sprinkler valve assembly comprising:
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a fluid passageway having an outlet and configured to connect to a source of pressurized fluid; a valve over the outlet, the valve configured to releasably oppose the force of the pressurized fluid; and a temperature-sensitive actuator coupled to the valve, the actuator comprising; a frangible bolt; and a shape-memory element capable of elongating at a pre-determined stress and temperature, wherein the frangible bolt applies compressive force to the shape-memory element; wherein the temperature-sensitive actuator is configured to actuate the valve by breaking the frangible bolt when the temperature of the shape-memory element reaches or exceeds the pre-determined temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A thermally-activated sprinkler valve assembly comprising:
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a fluid passageway having a valved outlet and configured to connect to a source of pressurized fluid; a linkage coupled to the valved outlet and configured to oppose the force of pressurized fluid and thereby maintain the valve closed; and a temperature-sensitive actuator coupled to the linkage, wherein the temperature-sensitive actuator comprises; a frangible bolt; and a shape-memory element capable of elongating as much as eight percent at a predetermined stress and temperature, wherein a length of the frangible bolt applies compressive force to the shape-memory element. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A thermally-activated sprinkler valve assembly comprising:
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a fluid passageway having a valved outlet and configured to connect to a source of pressurized fluid; a linkage bracket coupled to the valved outlet and configured to oppose the force of pressurized fluid and thereby maintain the valve closed; and a temperature-sensitive actuator coupled to the linkage bracket, wherein the temperature-sensitive actuator comprises; a frangible bolt; and a shape-memory element capable of elongating as much as eight percent at a pre-determined stress and temperature, wherein a length of the frangible bolt applies compressive force to the shape-memory element, an further wherein the plateau stress of the shape-memory element is approximately the same as the ultimate tensile strength of the bolt.
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26. Method of making a thermally-activated sprinkler valve assembly comprising:
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tuning a shape-memory element comprising single-crystal shape memory alloy to exert a pre-determined force at a predetermined temperature; forming a temperature-sensitive actuator by coupling a frangible bolt to the shape-memory element so that the shape-memory element is compressed; and coupling the actuator to a linkage, wherein the linkage is configured to couple with the valve of a fluid passageway having a valved outlet to oppose fluid pressure and maintain the valve closed. - View Dependent Claims (27, 28, 29, 30, 31)
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Specification