×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Failure of temperature sensors for boiler bed

Failure of temperature sensors for boiler bed

Failure of temperature sensors for boiler bed

(OP)
Hi
We have recurrent failure of 9 temperature sensors in our boiler bed. In the boiler, coal ash and bottom ash are burnt. We have type K thermocouple. Can you plz confirm what sensor type & material we should use? Also the type of material for the thermowell? Operating temperature is below:


Operating temp
/deg C
975-1000 deg C


Max process
temp/Deg C
1070 deg C

RE: Failure of temperature sensors for boiler bed

Type S, Inconel.

RE: Failure of temperature sensors for boiler bed

Quote (https://www.thermocoupleinfo.com/thermocouple-type...)

Type B Thermocouple (Platinum Rhodium – 30% / Platinum Rhodium – 6%) Temperature Range: Thermocouple grade wire, 32 to 3100F (0 to 1700C)
Type R Thermocouple (Platinum Rhodium -13% / Platinum) Temperature Range: Thermocouple grade wire, -58 to 2700F (-50 to 1480C)
Type S Thermocouple (Platinum Rhodium - 10% / Platinum) Temperature Range: Thermocouple Grade Wire Maximum continuous operating temperature: up to 2,912F (1600C)

How long did they work, if ever? Are you sure you didn't have a massive overtemperature event?
What do your temperature logs say?

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Failure of temperature sensors for boiler bed

It's seems you are pretty close at max with a type K especially if you don't have the right wire gage.
_____________________________________________________________________________________________________________
Type K Thermocouple (Nickel-Chromium / Nickel-Alumel): The type K is the most common type of thermocouple.
It’s inexpensive, accurate, reliable, and has a wide temperature range.
The type K is commonly found in nuclear applications because of its relative radiation hardness.
Maximum continuous temperature is around 1,100C.
_____________________________________________________________________________________________________________
Temperature Ranges for Type K Thermocouples
Type K thermocouples have a general temperature range of -200 to 1260°C (-326 to 2300°F), however there are some caveats to this:

If used for temperatures below 0°C special material is needed in order to meet the specified accuracies. Also, Special Limits of Error are not specified for temperatures below 0°C.
The ultimate suggested upper temperature limits for Type K are based on the size of the conductor used:
Wire Gage Diameter Maximum Suggested Temperature
#8 AWG 0.128” 1280°C/2300°F
#14 AWG 0.064” 1090°C/2000°F
#20 AWG 0.032” 980°C/1800°F
#24 AWG 0.020” 870°C/1600°F
#28 AWG 0.013” 870°C/1600°F
#30 AWG 0.010” 760°C/1400°F

Best regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: Failure of temperature sensors for boiler bed

Type K have horrific temp drift issues, Type N would be an option other than the Pt alloys.
An alloy 600 thermowell should be satisfactory and they are common.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close