Centrifugal air separator coil manufacturing tools and methods

Patent metadata

Field	Value
Publication number	US-10322368-B2
Application number	US-201615051382-A
Country	US
Kind code	B2
Filing date	Feb 23, 2016
Priority date	Feb 23, 2016
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

Tightly-coiled helical ducts for centrifugal air separators may be formed with the tools and methods disclosed herein. A helical coil toolset includes a helically grooved mandrel and an entry block. The helical groove of the mandrel has a small helix inside diameter relative to a width of the helical groove. The entry block has a guide channel to guide a tube to the helical groove and a mandrel channel to receive the mandrel. Methods include forming tubing into a tightly-coiled helical duct by filling a tube with fine particles, positioning the tube in the helical groove of a helically grooved mandrel, fixing the tube relative to the mandrel, assembling an entry block around the tube and around the mandrel, and bending the filled tube around the helically grooved mandrel into the tightly-coiled helical duct by rotating the mandrel relative to the entry block.

First claim

The invention claimed is:

1. A helical coil toolset comprising:
a helically grooved mandrel with a helical groove having a semicircular profile sized to accept an outside circumference of a tube in a sliding fit, wherein the helical groove has a helix inside diameter that is less than twice a width of the helical groove; and
an entry block with a guide channel and a mandrel channel, wherein the guide channel is sized to fit the outside circumference of the tube and to permit the tube to slide through, the guide channel has an exit that connects with the mandrel channel, the mandrel channel is configured to receive the helically grooved mandrel, the mandrel channel has a helical tube-contacting surface that extends into the helical groove of the helically grooved mandrel to engage the tube when the helically grooved mandrel is received in the mandrel channel and when the tube is positioned within the helical groove, and the guide channel is configured to direct the tube into the helical groove of the helically grooved mandrel.

2. The helical coil toolset of claim 1 , wherein the helical groove has a helix pitch of less than 4 times the outside diameter of the tube.

3. The helical coil toolset of claim 1 , wherein the helical groove includes at least 10 and less than 100 loops.

4. The helical coil toolset of claim 1 , wherein the guide channel of the entry block has an at least semicircular profile.

5. The helical coil toolset of claim 1 , wherein the exit of the guide channel is oriented at a helix angle of the helical groove when the helically grooved mandrel is in the mandrel channel.

6. The helical coil toolset of claim 1 , wherein the entry block includes at least two entry block members that are configured to selectively separate to accept the helically grooved mandrel in the mandrel channel and to selectively connect around the helically grooved mandrel to form the entry block.

7. The helical coil toolset of claim 1 , further comprising a clamping fixture configured to restrain the tube with respect to the helically grooved mandrel.

8. The helical coil toolset of claim 1 , further comprising a removal fixture configured to maintain a tightly-coiled helical shape of a tube wrapped around the helically grooved mandrel in the helical groove as the helically grooved mandrel is unthreaded from the tube.

9. The helical coil toolset of claim 8 , wherein the removal fixture includes a mandrel channel sized to fit the helically grooved mandrel and the tube wrapped around the helically grooved mandrel in the helical groove, and wherein the mandrel channel of the removal fixture includes a semicircular profile sized to accept the outside circumference of the tube.

10. The helical coil toolset of claim 1 in combination with the tube, wherein the helical groove is sized to accept a portion of the outside circumference of the tube in a sliding fit; and wherein the tube is a thin wall tube, is formed around the helically grooved mandrel, and is in the helical groove.

11. The combination of claim 10 , wherein the helically grooved mandrel includes a shaft that defines the helical groove, wherein the shaft consists essentially of steel, wherein the tube consists essentially of a 3000-series alloy of aluminum.

12. The combination of claim 10 , wherein the tube has an outside diameter of greater than 1 mm and less than 20 mm.

13. The combination of claim 10 , wherein the tube has a wall thickness to outside diameter ratio of less than 15%.

14. The combination of claim 10 , wherein the tube has an interior finish with an average roughness of less than 50 μm.

15. The combination of claim 10 , wherein the tube is filled with fine particles that have an average particle size of less than 180 μm and greater than 30 μm.

16. The helical coil toolset of claim 1 , wherein the helical tube-contacting surface comprises three loops.

17. A method for forming thin wall tubing into a tightly-coiled helical duct utilizing the helical coil toolset of claim 1 , the method comprising:
selecting a thin wall tube with an outside diameter and a wall thickness, wherein the outside diameter is greater than 1 mm and less than 20 mm, wherein the wall thickness is less than 15% of the outside diameter;
filling the thin wall tube with fine particles to form a filled tube;
positioning a portion of the thin wall tube in the helical groove of the helically grooved mandrel;
fixing a first section of the thin wall tube relative to the helically grooved mandrel, wherein the first section is proximate to the portion of the thin wall tube in the helical groove;
assembling the entry block around a second section of the thin wall tube and around the helically grooved mandrel, wherein the portion of the thin wall tube in the helical groove is between the first section and the second section of the thin wall tube; and
bending the filled tube around the helically grooved mandrel by rotating the helically grooved mandrel relative to the entry block assembled around the thin wall tube and helically grooved mandrel, wherein the bending includes forming a tightly-coiled helical duct within the helical groove from the thin wall tube with an outside diameter of the tightly-coiled helical duct that is less than four times the outside diameter of the thin wall tube.

18. The method of claim 17 , wherein the fine particles have an average particle size of less than 180 μm and greater than 30 μm, and wherein the bending includes maintaining an interior finish of the thin wall tube with an average roughness of less than 50 μm.

19. The method of claim 17 , further comprising unthreading the tightly-coiled helical duct from the helically groove mandrel, wherein the unthreading includes applying a removal fixture to the tightly-coiled helical duct to maintain a shape of the tightly-coiled helical duct as the tightly-coiled helical duct is unthreaded.

20. The method of claim 17 , further comprising forming a waste port in the tightly-coiled helical duct by forming an aperture through a wall of the tightly-coiled helical duct proximate to an end of a coil section of the tightly-coiled helical duct.

Assignees

• Boeing Co

Inventors

• Thieben Jr Paul F
• French Robert
• Suarez John

Classifications

• B01D2257/504

  Carbon dioxide · CPC title

• B01D2259/4575

  in aeroplanes or space ships · CPC title

• B01D2259/4566

  for use in transportation means · CPC title

• B21D9/15

  using filling material of indefinite shape, e.g. sand, plastic material (filling of tubes with such material B21D9/16) · CPC title

• B21D11/06

  Bending into helical or spiral form; Forming a succession of return bends, e.g. serpentine form (making helically seamed tubing B21C37/12) · CPC title