Claims
- 1. A prestressed tube comprising:
- inner and outer concentric, generally cylindrical walls substantially homogeneous so as to be free of internal stress-imparting members and having opposed cylindrical surfaces;
- a nonadhering lamina between said inner and said outer walls; and
- a pressure medium beween said nonadhering lamina and at least one of said inner and said outer walls, pressing agains the opposed cylindrical surfaces so as to bias said inner and said outer walls away from each other with a prestress force.
- 2. The prestressed tube of claim 1 wherein said said inner wall comprises a filament-wound tube including filaments in a resin matrix.
- 3. The prestressed tube of claim 2 wherein said filaments comprise glass fibers packed in an epoxy matrix with at least a 70% packing density.
- 4. The prestressed tube of claim 1 wherein said nonadhering lamina comprises a film of synthetic resin polymer.
- 5. The prestressed tube of claim 1 wherein said nonadhering lamina comprises waxed paper.
- 6. The prestressed tube of claim 1 wherein said pressure medium is disposed between said nonadhering lamina and said inner wall.
- 7. The prestressed tube of claim 1 wherein said pressure medium is disposed between said nonadhering lamina layer and said outer wall.
- 8. The prestressed tube of claim 1 wherein said pressure medium is disposed between said nonadhering lamina layer and both said inner and said outer walls.
- 9. A prestressed tube comprising:
- an inner generally cylindrical wall substantially homogeneous so as to be free of internal stress-imparting members;
- an outer generally cylindrical wall substantially homogeneous so as to be free of internal stres-imparting members concentrically disposed about said inner wall with outer and inner cylindrical surfaces of the inner and outer walls opposing one another, respectively;
- a nonadhering lamina layer between said inner and said outer walls;
- inlet means for injecting a pressure medium through at least one of said inside and said outside walls to said lamina layer; and
- a pressure medium fluidically injected through said inlet means penetrating between said lamina and at least one of said inner and said outer walls and forming a pressure medium-receiving cavity therebetween, said pressure medium thereafter hardening to form a prestressing pressure force pressing against the cylindrical surfaces so as to bias said inner and said outer walls away from each other.
- 10. The prestressed tube of claim 9 wherein said pressure medium is disposed between said nonadhering lamina and said inner wall.
- 11. The prestressed tube of claim 9 wherein said pressure medium is disposed between said nonadhering lamina layer and said outer wall.
- 12. The prestressed tube of claim 9 wherein said pressure medium is disposed between said nonadhering lamina layer and both said inner and said outer walls.
Parent Case Info
This application is a division of U.S. Ser. No. 818,203, filed Jan. 13, 1986, now U.S. Pat. No. 4,774,872, which is a continuation-in-part of Ser. No. 506,430 filed June 21, 1983 U.S. Pat. No. 4,624,173.
US Referenced Citations (21)
Foreign Referenced Citations (4)
Number |
Date |
Country |
222557 |
Jul 1962 |
ATX |
741460 |
Apr 1970 |
BEX |
2710011 |
Sep 1978 |
DEX |
179238 |
May 1962 |
SEX |
Divisions (1)
|
Number |
Date |
Country |
Parent |
818203 |
Jan 1986 |
|
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
506430 |
Jun 1983 |
|