SPRINKLER VALVE WITH ACTIVE ACTUATION

• US 20100006304A1
• Filed: 07/15/2009
• Published: 01/14/2010
• Est. Priority Date: 01/25/2007
• Status: Active Grant

• Current Assignee: TiNi Alloy Company
• Original Assignee: TiNi Alloy Company
• Inventors: Martynov, Valery, Gilbertson, Roger Graham, Johnson, Alfred David
• Granted Patent: US 8,584,767 B2
• Time in Patent Office: Days
• US Class Current: 169/19
• CPC Class Codes: A62C 37/16 with thermally-expansible links

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 shape memory element typically communicates with the valve so as to force it open. 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.

Claims

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 predetermined 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 predetermined temperature;

further wherein the shape-memory element communicates with the valve to open the valve.

2. The valve assembly of claim 1, further wherein the temperature-sensitive actuator is coupled to the valve through a linkage that is configured to oppose the force of pressurized fluid and thereby maintain the valve closed.

3. The valve assembly of claim 2, wherein the temperature-sensitive actuator is positioned in parallel with the linkage.

4. The valved assembly of claim 1, wherein temperature-sensitive actuator is configured so that force from the pressurized fluid is not substantially transmitted to the shape-memory element.

5. The valve assembly of claim 1, wherein the force generated at the plateau stress of the shape-memory element is approximately the same as the ultimate tensile strength of the bolt.

6. The valve assembly of claim 1, further comprising a nut securing the frangible bolt to the shape-memory element.

7. The valve assembly of claim 1, further comprising a frame portion extending from the fluid passageway.

8. The valve assembly of claim 1, wherein the frangible bolt is notched.

9. The valve assembly of claim 1, wherein the frangible bolt is a titanium bolt.

10. The valve assembly of claim 1, wherein the shape-memory element is a single-crystal CuAlNi alloy or a single-crystal CuAlMn alloy.

11. The valve assembly of claim 1, wherein the shape-memory element is a tempered single-crystal shape memory alloy.

12. The valve assembly of claim 1, wherein the shape-memory element comprises a cylinder at least partially surrounding the frangible bolt.

13. A thermally-activated sprinkler valve assembly comprising:

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 pre-determined stress and temperature, wherein a length of the frangible bolt applies compressive force to the shape-memory element, further wherein the shape-memory element communicates with the valve and is configured to apply force to open the valve.

14. The valve assembly of claim 13, wherein the frangible bolt is notched.

15. The valve assembly of claim 13, wherein the shape-memory element is a single-crystal CuAlNi alloy or a single-crystal CuAlMn alloy.

16. The valve assembly of claim 13, wherein the shape-memory element is a tempered single-crystal shape memory alloy.

17. The valve assembly of claim 13, wherein the shape-memory element comprises a cylinder at least partially surrounding the frangible bolt.

18. The valved assembly of claim 13, wherein temperature-sensitive actuator is configured so that force from the pressurized fluid is not substantially transmitted to the shape-memory element.

19. The valve assembly of claim 13, wherein the plateau stress of the shape-memory element is approximately the same as the ultimate tensile stress of the bolt.

20. A method of activating a thermally-activated sprinkler valve assembly comprising:

applying heat to activate an actuator, wherein the actuator comprises a shape-memory element comprising a single-crystal shape memory alloy, a frangible element, and 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;

expanding the shape-memory element to break a frangible bolt to release the linkage from the valve and to apply force to open the valve.