High temperature electrical insolator that repels carbon deposits

Click For Summary

Discussion Overview

The discussion revolves around the search for materials that can withstand high temperatures (1250 C) in a CVI furnace while either repelling carbon deposits or reacting with them to form non-conductive compounds. The context includes considerations for electrical insulation and the prevention of short circuits in heating element supports.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about materials that can handle high temperatures and either repel or react with carbon deposits to prevent electrical conductivity.
  • Another participant suggests using a shroud around the support to shield it from carbon deposits, although acknowledges that this may not be effective if the carbon originates from a gas.
  • A third participant mentions that high voltage and extremely high voltage equipment often employs corrugated surfaces to increase the path length for electrical insulation and may have surface treatments that repel contaminants.
  • A participant provides details about the carbon deposit thickness observed over a two-day period and discusses the challenges of sealing at high temperatures while maintaining gas flow for protection.
  • There is a suggestion to direct nitrogen flow towards the supports as a potential solution, along with the idea of using a shroud to create an inert atmosphere.

Areas of Agreement / Disagreement

Participants express various approaches and ideas, but there is no consensus on a definitive solution or material. The discussion remains open with multiple competing views and suggestions.

Contextual Notes

The discussion highlights the limitations of sealing methods at high temperatures and the challenges associated with maintaining an inert atmosphere while preventing carbon deposits.

Quince
Messages
2
Reaction score
0
Is there any material/s that will handle CVI furnace temperatures (1250 C) and will either repel carbon deposits or react with it to create a compound that is not electric conductive? Trying to contain power to the heating element without shorting it to the base/ground through heating element supports.
 
Last edited by a moderator:
Engineering news on Phys.org
Not offhand. But can you but a shroud around most of the support length to shadow it? Of course if the Carbon is from a decomposing flowing gas this may not help much. A labyrinth seal at the open end of the shroud may be the next step.

(Here is an attempted sketch but it may not render correctly)

Code: 
               ___________ shroud
               | 
element        |______________ to wall
suppoort-------|
               |__________

Cheers,
Tom
 
IIRC, HV & EHV pylon, transformer & switch-gear 'stand-offs' are corrugated to increase path length, but may also have a surface finish / treatment proven to repel muck.

Could be worth a look...

FWIW, even such do need jet-wash cleaning from time to time: My wife got stuck in a shopping centre lift when contract cleaners mistakenly sprayed the 'live' set at local grid station, tripped half the city...
 
Tom, the deposit IS from gas and about .003" (.076 mm) in a single 2 day run. I have nitrogen flowing to protect, but the main box will always bleed some gas. Hard to seal at that temperature without sinking the boat. Rebuilding the supports is a long, expensive and painful process. Finding a solution will be quite elegant and beneficial, maybe, to other applications.

Nik, I’ll have to find out what IIRC, HV, EHV and FWIW stand for.
 
Oops.
'If I Remember Correctly'
'high voltage'
'Extremely high voltage'
'for what its worth...'
:-)
 
Quince said:
Tom, the deposit IS from gas and about .003" (.076 mm) in a single 2 day run. I have nitrogen flowing to protect, but the main box will always bleed some gas. Hard to seal at that temperature without sinking the boat. Rebuilding the supports is a long, expensive and painful process. Finding a solution will be quite elegant and beneficial, maybe, to other applications.
Understood. Can you plumb the Nitrogen so it is aimed at the supports? Probably not cheap but maybe the cheapest.

As a last-resort possibility, consider the shroud approach with the Nitrogen delivered inside the shroud for a continuous inert atmosphere.

Interesting problem. please keep us updated.

Cheers,
Tom
 

Similar threads

High Temperature and Very High Temperature Materials
  • · Replies 7 ·
Replies
7
Views
3K
Lithium-Sulfur Batteries? Maybe
  • · Replies 2 ·
Replies
2
Views
2K
Calculation of electrical mean free path in nanomaterials?
  • · Replies 0 ·
Replies
0
Views
3K
High Temperature, Non-conductive Material
  • · Replies 9 ·
Replies
9
Views
10K
How to calculate the electrical power output using the Organic Rankine Cycle?
  • · Replies 18 ·
Replies
18
Views
5K
Synhelion -- Using solar heliostat farms to create liquid fuels from Water Vapor and CO2
  • · Replies 7 ·
Replies
7
Views
3K
Co-free, High-Energy, Fast-Charging, Long-Lasting Li-Ion Batteries?
  • · Replies 0 ·
Replies
0
Views
3K
Gold hydride - what is the significance?
  • · Replies 0 ·
Replies
0
Views
745
Undergrad Alternative materials in high temperature superconductors
  • · Replies 13 ·
Replies
13
Views
3K
Thermal insulating materials suitable for making piston and cylinder?
  • · Replies 6 ·
Replies
6
Views
2K