Windshield and sound-barrier for seismic sensors
A system and method for reducing acoustic, wind or other background noise that may interfere with sensing of a seismic signal is provided. More specifically, a shield is provided to enclose a geophone and thereby protect it from harmful noise. The shield may comprise a rigid shell, a structural damping material, an acoustically absorptive material, and a compliant seal for coupling the shield to the ground or reference surface.
1. A system for sensing motion of a surface comprising:
a seismic sensor coupled to the surface; and
a shield configured to enclose the seismic sensor, wherein the shield is configured to provide an acoustic transmission loss, a wind noise loss, or both;
wherein the shield further comprises a compliant seal that couples the shield to the surface, and at least three distinct layers selected from a group consisting of a rigid shell, an acoustically absorptive material layer, a structural damping material layer and a mass layer.
2. The system of claim 1 , wherein the shield comprises:
a substantially rigid shell.
3. The system of claim 2 , wherein the shell weighs at least about 1 pound per square foot.
4. The system of claim 2 , wherein the shell weighs about 2 pounds per square foot.
5. The system of claim 2 , wherein the shell comprises metal.
6. The system of claim 2 , wherein the shell comprises fiberglass.
7. The system of claim 2 , wherein the shell comprises a lead vinyl layer.
8. The system of claim 2 , wherein a cross section of the shell is substantially circular in shape.
9. The system of claim 2 , wherein the shell is about 2 feet in diameter.
10. The system of claim 2 , wherein the shield further comprises a mass layer coupled to the shell.
11. The system of claim 10 , wherein the mass layer weighs at least about 1 pound per square foot.
12. The system of claim 10 , wherein the mass layer weighs about 2 pounds per square foot.
13. The system of claim 10 , wherein the mass layer comprises a lead vinyl layer.
14. The system of claim 2 , wherein the shield further comprises:
a structural damping material layer coupled to the shell.
15. The system of claim 14 , wherein the structural damping material layer comprises an elastomeric material.
16. The system of claim 14 , wherein the structural damping material layer comprises a rubber material.
17. The system of claim 14 , wherein the structural damping material layer comprises a plastic material.
18. The system of claim 14 , wherein the shield further comprises:
an acoustically absorptive material layer coupled to the structural damping material layer.
19. The system of claim 18 , wherein the acoustically absorptive material layer comprises an open cell foam.
20. The system of claim 18 , wherein the acoustically absorptive material comprises a fiberglass.
21. The system of claim 1 , wherein the complaint seal comprises an air filled rubber tube.
22. The system of claim 1 , wherein the compliant seal comprises a sand filled rubber tube.
23. A system for sensing motion of a reference surface comprising:
a seismic sensor, a shield, and a suspension;
wherein the shield is coupled to the seismic sensor using the suspension, the seismic sensor is coupled to the surface, and the shield is configured to enclose the seismic sensor and to provide an acoustic transmission loss, a wind noise loss, or both, and
wherein the shield comprises at least three distinct layers selected from a group consisting of a rigid shell, an acoustically absorptive material layer, a structural damping material layer and a mass layer.
24. The system of claim 23 , wherein the shield comprises:
a substantially rigid shell.
25. The system of claim 24 , wherein the shield further comprises: a structural damping material layer coupled to the shell;
an acoustically absorptive material layer coupled to the structural damping material layer; and
a compliant seal, wherein the compliant seal couples the shell to the surface.
26. The system of claim 23 , wherein the suspension is configured such that the shield provides a bias mass to the seismic sensor.
27. A method for sensing motion of a surface comprising:
coupling a seismic sensor to the surface; and
enclosing the seismic sensor with a shield, wherein the shield is configured to provide an acoustic transmission loss, a wind noise loss, or both, and
wherein the shield further comprises a compliant seal, wherein the compliant seal couples the shield to the surface, and at least three distinct layers selected from a group consisting of a rigid shell, an acoustically absorptive material layer, a structural damping material layer and a mass layer.
28. The method of claim 27 , wherein the shield comprises:
a substantially rigid shell.
29. The method of claim 28 , wherein the shield further comprises:
a structural damping material layer coupled to the shell.
30. The method of claim 29 , wherein the shield further comprises:
an acoustically absorptive material layer coupled to the structural damping material layer.