Heatable line pipe and a method for producing the heatable pipe

Patent metadata

Field	Value
Publication number	US-10094505-B2
Application number	US-201313892534-A
Country	US
Kind code	B2
Filing date	May 13, 2013
Priority date	May 14, 2012
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

A heatable line pipe useful for diesel fuel systems and fuel cell systems is provided. The heatable line pipe comprises in order from an inside of the pipe: a) an electrically insulating inner layer; b) a first electrically conductive layer; c) at least two current leads wound spirally around the first electrically conductive layer; d) a second electrically conductive layer over the at least two current leads forming a surface; and e) an outer cladding of an electrically insulating plastic material. The thickness of the second electrically conductive layer is 0.1 to 1.5 mm, and the at least two current leads form wave peaks in the surface of the second electrically conductive layer. The line pipe has the advantage that a fall in heating performance over the lifetime is effectively prevented.

First claim

The invention claimed is:

1. A heatable line pipe, comprising, in order from an inside of the pipe:
a) an electrically insulating inner layer;
b) a first electrically conductive layer;
c) at least two current leads wound spirally around the first electrically conductive layer such that a distance from one another is from 2 to 20 mm;
d) a second electrically conductive layer over the at least two current leads forming a surface; and
e) an outer cladding of an electrically insulating plastic material;
wherein
the at least two current leads are embedded and bound in the first and second electrically conductive layers,
a thickness of the second electrically conductive layer is 0.1 to 1.5 mm, and
the at least two current leads form wave peaks having a difference between a wave peak and a wave valley of from 0.1 mm to 1.2 mm in the surface of the second electrically conductive layer.

2. The heatable line pipe according to claim 1 , wherein the electrically insulating inner layer comprises a plurality of sublayers.

3. The heatable line pipe according to claim 1 , wherein the at least two current leads are wires, stranded cords or ribbons.

4. The heatable line pipe according to claim 1 , wherein a thickness of the at least two current leads is from 0.1 to 2 mm.

5. The heatable line pipe according to claim 1 , wherein a difference of the wave peak and wave valley is from 0.3 mm to 0.5 mm.

6. The heatable line pipe according to claim 1 , wherein the first and second electrically conductive layers comprise at least one electrically conductive component selected from the group of components consisting of conductive carbon black, conductive graphite powder and conductive graphite fibrils.

7. The heatable line pipe according to claim 1 , wherein a volume resistivity of the first and second electrically conductive layers is from 10 −3 to 10 10 Ωm,
wherein when the volume resistivity is from 10 4 to 10 10 Ωm, measurement of the volume resistivity is in accordance with DIN IEC 60093 and when the volume resistivity is from 10 −3 to 10 4 Ωm measurement of the volume resistivity is in accordance with EN ISO 3915.

8. The heatable line pipe according to claim 1 , wherein the outer cladding is an extruded layer and the outer cladding comprises a wave contour matching the wave peaks of the second electrically conductive layer.

9. The heatable line pipe according to claim 1 , wherein the outer cladding is a smooth pipe or corrugated pipe fixed by force contact connection with the wave peaks.

Assignees

• Goering Rainer
• Boeer Michael
• Franosch Juergen
• Westmeier Joerg
• Schwarzkopf Otfried
• De Beer Daniel
• Evonik Degussa Gmbh
• Voss Automotive Gmbh

Inventors

• Goering Rainer
• Boeer Michael
• Franosch Juergen
• Westmeier Joerg
• Schwarzkopf Otfried
• De Beer Daniel

Classifications

• F16L53/38 Primary

  using elongate electric heating elements, e.g. wires or ribbons · CPC title

• B29C48/154

  Coating solid articles, i.e. non-hollow articles · CPC title

• B29K2995/0007

  Insulating · CPC title

• B29C48/09

  Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels · CPC title

• F01N3/2066

  Selective catalytic reduction [SCR] · CPC title