Gaskets for sealing two mating surfaces are described. The gaskets have an outer portion including a core between two sealing layers and an inner portion made of a deformable material and located in an aperature in the outer portion. The thickness of the inner portion is greater than the thickness of the outer portion. The inner portion may include a chemical treatment agent that can provide chemical protection to the mating surfaces. Methods of producing the gaskets and methods of using the gaskets for sealing joints, including corroded joints, are also described.
1. A gasket for sealing two mating surfaces comprising:
a) an outer portion having an upper surface, a lower surface, and an innermost edge located between the upper and lower surfaces, wherein the outer portion comprises
(i) a core and
(ii) two sealing layers,
wherein the core is between and adjacent to the two sealing layers,
wherein one or both of the core and the sealing layers define the innermost edge of the outer portion, and
wherein the innermost edge defines a first aperture in the outer portion;
b) an inner portion comprising:
(i) a deformable material;
(ii) an innermost edge defining a second aperture; and
(iii) an outermost region secured to the innermost edge of the outer portion wherein the outermost region of the inner portion is in continuous contact with the innermost edge of the outer portion proximate the upper surface of the outer portion and in continuous contact with the innermost edge of the outer portion proximate the lower surface of the outer portion,
wherein the inner portion is located within the first aperture,
wherein a thickness of the inner portion is greater than a thickness of the outer portion.
2. The gasket of claim 1 , wherein the inner portion further comprises a chemical treatment agent.
3. The gasket of claim 1 , wherein the core comprises solid metal and includes a series of serrations formed on facing surfaces thereof.
4. The gasket of claim 2 , wherein the chemical treatment agent comprises a corrosion treatment agent.
5. The gasket of claim 4 , wherein the chemical treatment agent is present in the deformable material in a range of 0.01% to 50% w/w of the inner portion.
6. The gasket of claim 1 , wherein the deformable material is more compressible than the sealing layers.
7. The gasket of claim 1 , wherein the sealing layers comprise a material selected from the group consisting of PTFE, graphite, vermiculite based sealing material, non-asbestos sheet, and a soft metallic face.
8. The gasket of claim 7 , wherein the sealing layers comprise biaxially orientated PTFE.
9. The gasket of claim 1 , wherein the deformable material comprises microcellular PTFE.
10. The gasket of claim 9 , wherein the PTFE comprises biaxially orientated microcellular PTFE.
11. The gasket of claim 2 , wherein the deformable material comprises a microcellular structure and is impregnated with the chemical treatment agent.
12. The gasket of claim 2 , wherein the chemical treatment agent comprises a rust inhibitor.
13. The gasket of claim 12 , wherein the rust inhibitor is selected from the group consisting of salts of phosphates, molybdates, nitrites, borates, phosphonates, iron chelating agents and sequestering agents.
14. The gasket of claim 1 , further comprising a handle extension for use in positioning the gasket.
15. The gasket of claim 14 , wherein the extension is removable from the gasket.
16. The gasket of claim 1 , further comprising at least one coplanar projection extending from the innermost edge of the outer portion into the inner portion.
17. The gasket of claim 1 , wherein the outer portion is less flexible than the inner portion.
18. The gasket of claim 1 , wherein the thickness of the inner portion is greater than the thickness of the outer portion so that in use the inner portion deforms to a greater extent than the outer portion.
19. A gasket comprising
(a) an outer portion having an upper surface, a lower surface, and innermost edge located between the upper and lower surfaces, wherein the outer portion comprises
(i) a core having top and bottom surfaces, and
(ii) a sealing material adjacent to one or both of the top and bottom surfaces of the core;
wherein the an innermost edge of the outer portion is defined by the core or the sealing material, and
(b) an inner portion comprising a deformable material and comprising
(i) an outermost edge secured to the innermost edge of the outer portion,
wherein the outermost edge of the inner portion is in continuous contact with the innermost edge of the outer portion proximate the upper surface of the outer portion and in continuous contact with the innermost edge of the outer portion proximate the lower surface of the outer portion; and
(ii) an innermost edge, wherein the innermost edge defines an aperture;
wherein the inner portion has a thickness greater than a thickness of the outer portion.
20. The gasket of claim 19 , wherein the outermost edge of the inner portion is continuously close fitting with the innermost edge of the outer portion.
21. The gasket of claim 19 , wherein the outermost edge of the inner portion overlaps the innermost edge of the outer portion.
22. The gasket of claim 19 , wherein the inner portion is secured to the outer portion.
23. The gasket of claim 22 , further comprising at least one fixing component to secure the outer portion to the inner portion.
24. The gasket of claim 23 , wherein the fixing component is at least one projection that extends from the innermost edge of the outer portion into the inner portion thereby securing the inner portion to the outer portion.
25. The gasket of claim 19 , wherein the inner portion further comprises a chemical treatment agent.
26. The gasket of claim 25 , wherein the chemical treatment agent comprises a corrosion inhibitor.
27. The gasket of claim 25 , wherein the chemical treatment agent comprises a rust inhibitor.
28. The gasket of claim 27 , wherein the rust inhibitor is selected from the group consisting of salts of phosphates, molybdates, nitrates, borates, phosphonates, iron chelating agents and sequestering agents.
29. The gasket of claim 25 , wherein the chemical treatment agent is present in an amount of from 0.01% to 50% by weight of the inner portion.
30. The gasket of claim 19 , wherein the sealing material is selected from the group consisting of PTFE, graphite, vermiculite based sealing material, non-asbestos sheet, and soft metallic face.
31. The gasket of claim 30 , wherein the sealing material is biaxially oriented PTFE.
32. The gasket of claim 19 , wherein the deformable material comprises microcellular PTFE.
33. The gasket of claim 32 , wherein the PTFE comprises biaxially oriented microcellular PTFE.
34. The gasket of claim 19 , wherein the inner portion is more compressible than the sealing material.
35. The gasket of claim 19 , further comprising serrations on one or both of the top surface and the bottom surface of the core and surrounding the first aperture.
36. The gasket of claim 19 , further comprising a handle extension for use in positioning the gasket, wherein the handle extension is removably attached to the outer portion of the gasket and configured to extend outside a surface to be sealed.
37. The gasket of claim 1 , wherein the inner portion has a compressibility of 30-90%.
38. The gasket of claim 19 , wherein the inner portion has a compressibility of 30-90%.
39. The gasket of claim 1 , wherein both the core and sealing layers define the inner edge of the outer portion.
40. The gasket of claim 1 , wherein the core has a first inside radius and each of the two sealing layers has a second inside radius, the first inside radius and second inside radius being substantially the same length.
41. A gasket comprising
(a) an outer portion having an upper surface, a lower surface, and innermost edge located between the upper and lower surfaces, wherein the outer portion comprises
(i) a core having top and bottom surfaces comprising a series of serrations, and
(ii) a sealing material adjacent to one or both of the top and bottom surfaces and overlaying the serrations;
wherein the innermost edge of the outer portion is defined by the core and/or the sealing material;
(b) an inner portion comprising a deformable material and comprising
(i) an outermost edge secured to the innermost edge of the outer portion, wherein the outermost edge of the inner portion is in contact with the innermost edge of the outer portion proximate the upper surface of the outer portion and in contact with the innermost edge of the outer portion proximate the lower surface of the outer portion, and
(ii) an innermost edge, wherein the innermost edge defines an aperture,
wherein the inner portion has a thickness greater than a thickness of the outer portion; and
(c) at least one projection extending from the innermost edge of the outer portion into the inner portion.
42. The gasket of claim 1 , wherein the innermost edge connects the upper surface and lower surface.
43. The gasket of claim 1 , wherein the core defines the innermost edge of the outer portion.
44. The gasket of claim 1 , wherein both the core and the sealing layers define the innermost edge of the outer portion.
45. The gasket of claim 19 , wherein the innermost edge of the outer portion is defined by the core.