Method for making insulated pipe

• US 4,581,804 A
• Filed: 09/12/1975
• Issued: 04/15/1986
• Est. Priority Date: 09/12/1975
• Status: Expired due to Term

• Current Assignee: Ameron International Corporation (NOV, Inc.)
• Original Assignee: Ameron International Corporation (NOV, Inc.)
• Inventors: McLaughlin, Hugh T.
• Primary Examiner(s): Moon, Charlie T.
• Application Number:
  US06/612,659
• Time in Patent Office: 3,868 Days
• Field of Search: 29/451, 29/235, 29/423, 29/455 R, 29/421 R, 29/157 R, 138/149
• US Class Current: 29/451
• CPC Class Codes: F16L 59/143 Pre-insulated pipes
• CPC Class Codes: F16L 59/166 covering the end of an insulated section
• CPC Class Codes: F16L 59/182 Joints with sleeve or socket in general F16L21/00
• CPC Class Codes: F16L 9/121 with three layers
• CPC Class Codes: Y10T 29/49428 Gas and water specific plumbing component making
• CPC Class Codes: Y10T 29/49872 Confining elastic part in socket
• CPC Class Codes: Y10T 29/53657 to apply or remove a resilient article [e.g., tube, sleeve, etc.]

Abstract

An insulated pipe for conducting high and low temperature fluids includes a rigid carrier pipe, a layer of volumetrically compressible insulating material around the O.D. of the carrier pipe, and a protective outer pipe around the insulating layer. The method of making the pipe product includes placing a closed flexible bag around the carrier pipe and the insulating layer, and then drawing a vacuum on the interior of the bag to compress the insulating layer. The outer pipe is slid lengthwise over the compressed insulating layer, and the vacuum is then removed to allow the insulation to partially expand and fill the annulus between the carrier pipe and the outer pipe.

Claims

1. A method for making insulated pipe comprising the steps of wrapping a layer of resilient, volumetrically compressible insulating material around the exterior of a carrier pipe;

placing a flexible enclosure around the insulation layer;

drawing a vacuum on the interior of the enclosure to compress the insulation layer around the carrier pipe exterior;

placing an outer shell over the compressed insulation layer and enclosure so the outer shell is around the carrier pipe; and

releasing the vacuum in the enclosure so that the resilient insulation layer expands to fill the space between the carrier pipe and the inner surface of the shell.

2. The method according to claim 1 including the step of providing an insulation layer having a normal O.D. larger than the I.D. of the outer shell so that the insulation layer partially recovers its original volume after the volume is released to remain compressed from its normal condition between the carrier pipe and the outer shell.

3. The method according to claim 1 including the step of providing an insulation layer comprising fibrous insulating felt.

4. The method according to claim 1 including the step of providing an insulation layer comprising a porous foam material.

5. The method according to claim 1 including the step of providing an outer shell comprising a rigid outer pipe concentrically disposed around the carrier pipe.

6. The method according to claim 5 including the step of providing an outer shell comprising a filament-wound plastic pipe made from a thermosetting resinous material.

7. The method according to claim 6 including the step of providing a carrier pipe comprising a filament-wound plastic pipe made from a thermosetting resinous material.

8. The method according to claim 7 including the step of providing an insulation layer having a normal O.D. larger than the I.D. of the outer shell so that the insulation layer remains in a compressed condition between the outer shell and the carrier pipe after the vacuum is released.

9. The method according to claim 1 in which the enclosure comprises a flexible closed bag;

and including the step of placing the closed bag around the entire exterior of the carrier pipe and the insulating layer prior to producing said vacuum.

10. A method for making insulated pipe which includes a carrier pipe, an outer shell surrounding the carrier pipe, and a layer of insulation in the annulus between the carrier pipe and outer shell, the method including the steps of wrapping a layer of porous, resilient, volumetrically compressible self-supporting insulation around the exterior of said carrier pipe, the insulation layer having a cross-sectional thickness such that its outside diameter is greater than the inside diameter of said outer shell;

placing a flexible enclosure around the insulation layer;

producing a vacuum in the interior of the enclosure to compress the cross-sectional thickness of the insulation layer around the exterior of the carrier pipe;

placing said outer shell over the compressed insulation layer and enclosure so the outer shell surrounds the carrier pipe; and

releasing the vacuum in the enclosure to partially expand the cross-sectional thickness of the resilient insulation layer to allow the layer to fill the annulus between the carrier pipe and the shell and remain compressed in the annulus by the expansive force exerted on the inside surface of the shell by the resilient layer.

11. The method according to claim 10 in which the enclosure comprises a flexible closed bag;

and including the step of placing the closed bag around the entire exterior of the carrier pipe and the insulating layer prior to producing said vacuum.

12. The method according to claim 11 including the step of providing an outer shell comprising a filament-wound plastic pipe made from a thermosetting resinous material, and providing a carrier pipe comprising a filament-wound plastic pipe made of thermosetting resinous material.

13. The method according to claim 12 including the step of placing end seals over the annular end surface of the insulation layer at opposite ends of the pipe after the vacuum is released.

14. The method according to claim 11 in which the evacuated closed bag has closed ends, and including the step of cutting the closed ends of the bag to release the vacuum.

15. A method of manufacturing a heat insulator which comprises the steps of introducing between an outer casing and an inner casing an insert comprising a mass of fibrous material which has been compressed by vacuum-packing it in a hermetically sealed bag, and then unsealing said bag to permit said material to expand within said casing.