This website requires certain cookies to work and uses other cookies to help you have the best experience. By visiting this website, certain cookies have already been set, which you may delete and block. By closing this message or continuing to use our site, you agree to the use of cookies. Visit our updated privacy and cookie policy to learn more.
This Website Uses Cookies
By closing this message or continuing to use our site, you agree to our cookie policy. Learn More
This website requires certain cookies to work and uses other cookies to help you have the best experience. By visiting this website, certain cookies have already been set, which you may delete and block. By closing this message or continuing to use our site, you agree to the use of cookies. Visit our updated privacy and cookie policy to learn more.
Ceramic Industry logo
search
cart
  • Sign In
  • Create Account
  • Sign Out
  • My Account
Ceramic Industry logo
  • News
    • Ceramic Industry News
    • Market Trends
    • Events Calendar
  • Topics
    • Advanced Ceramics
    • Refractories
    • Glass
    • Whitewares
    • Brick and Structural Clay
    • Raw and Processed Materials
    • Firing and Drying
    • Batching and Materials Handling
    • Forming and Finishing
    • Instrumentation & Lab Equipment
    • Decorating
  • New Products
    • New Products
    • Virtual Supplier Brochures
  • Columns
    • IP in Depth
    • Glass Works
    • Ceramic Decorating
    • Taking Care of Business
  • CI Top 14
  • Multimedia
    • Videos
    • Podcasts
    • Photo Galleries
    • Mobile App
    • Webinars
  • Directories
    • Data Book & Buyers' Guide
    • Ceramic Components Directory
    • Materials Handbook
    • Equipment Digest
    • R&D Lab Equipment & Instrumentation
    • Services Directory
    • Take a Tour
  • Explore
    • CI Supplier of the Year Award
    • Blog
    • CI Store
    • Raw & Manufactured Materials Overview
    • Material Properties Charts
    • Market Research
  • Magazine
    • Current Issue
    • Digital Edition
    • Classifieds & Services Marketplace
    • Advertiser Index
  • Contact
    • Classifieds & Services Marketplace
    • Custom Content Marketing Services
Home » KILN CONNECTION: Interpreting Data Logger Results
ColumnsKiln Connection

KILN CONNECTION: Interpreting Data Logger Results

April 1, 2004
Ralph Ruark
Reprints
No Comments
Data loggers that produce the true thermal history of the firing process are effective consulting tools. However, to fully take advantage of this technology, we have to set up the hardware and software so the diagnosis of problems becomes easier.

My normal course of consulting routinely involves analyzing periodic and tunnel kilns, adjusting combustion systems and controls, or modifying kiln designs to improve performance. Data loggers that produce the true thermal history of the firing process are some of the most effective tools available for these purposes. However, to fully take advantage of this excellent technology, we have to set up the hardware and software so the diagnosis of problems becomes easier.

The Equipment

Several systems are commercially available for this task. Since most of my clients use the Datapaq system, my comments will refer to this device. It consists of a data logger and thermal protection, as well as software that allows for the setup of collection, data download and tools for analysis. This system's use of analysis tools makes it far more useful than the old time "traveling thermocouple" curve. Additionally, a new enhancement-real-time monitoring-allows users to see the data as the firing schedule progresses, and if you wish to share the data, you need only e-mail the file to others.

The Procedure

When you run a thermocouple (TC) curve for the first time, you will probably see a variety of temperature transients, hot and cold spots, and a whole range of firing anomalies. Since everything happens for a reason (believe it or not!) it is imperative to have a picture of every kiln input and output to figure out what is creating the range in uniformity, as well as the various transients in temperature.

Use of the mimic diagram-a kiln map-is critical to understanding the Datapaq curve. The location of all of the devices-exhaust offtakes, recirculation fans, burners, etc.-is essential to understanding the results and then making improvements. Often, the reason for an improper temperature transient can be traced to a kiln device such as an exhaust port, air jet, hot burner, etc.

The mimic diagram should be accurately prepared and saved as a "process." It is then loaded (selected) in the run and need only be developed one time for the kiln that is being studied.

Setup of the thermocouples is straightforward. Develop a TC map based on setting. The first trial may be general-simply test the outer boundaries of the setting combined with a few points inside the setting. More detailed tests can also be designed to test isolated trouble spots where losses occur. If ware cracks in a particular portion of the kiln car, that area should be scrutinized by locating thermocouples in that position.

Analysis Tools

Numerous tools are built into the software, and these tools calculate critical data for problem solving. In the Datapaq software, for example, the following tools are standard.
  • Max/min temperature is useful in determining the relative amount of time at a given temperature. It helps define the soaking time or cumulative time for oxidation.
  • Time at temperature helps to further define the soaking time by providing a calculation of time above a certain temperature.
  • Rise and fall time allows for the calculation of heating and cooling rates.
  • Slopes provides a calculation of the rate of heating and cooling for zoomed areas on the graph. This is very helpful for diagnosing heating and cooling cracks.
  • Peak differences allows for a quick calculation of differential temperature.
  • Q1 slope shows the heating and cooling rates through the quartz inversion-valuable information to avoid heating cracks and cooling cracks.
  • HWI (heat work index) provides the relative heat work applied to all of the TC-monitored positions.

Another feature is the system's capability to overlay curves, allowing for the comparison of different kiln tests. This provides the ability to accurately monitor your adjustments to see if you're making progress.

Interpretation and Improvement

Most of the analysis tools can be configured to look at distinct segments and rates of temperature. Often, when defects are developed in firing, they occur in different areas of the kiln car setting. Using analysis tools can tell us what is different in the thermal history of one part of the kiln car vs. another. You can often diagnose problems by comparing the thermal history of "good" setting areas vs. "bad" setting areas.

At that point, we can look at the mimic diagram and determine what devices are available to help improve the situation, or even evaluate modifications to the equipment.

Ralph Ruark is a registered professional engineer with degrees in ceramic engineering and business, and 28 years of experience in the ceramic industry. He formed Ruark Engineering Inc. several years ago and serves as a technical consultant to a number of ceramic manufacturers and kiln companies. He is dedicated to assisting ceramic companies with a variety of kiln and firing needs, leading kiln analysis efforts, providing training expertise, and improving operations. Ruark can be reached at (941) 360-3111, fax (941) 360-3211, e-mail ruarkeng@aol.com or online at http://www.ruarkengineering.com .

Recent Articles by Ralph Ruark

What You Need to Know About NFPA 86-2015

Investing in Ceramics: Conrad Dressler - Artist, Inventor, Founder

Carbon - Something Old, Something New

Ahead of the Curve

Kiln Connection: A Farewell

Ralph-ruark-107px

Ralph Ruark is president of Swindell Dressler International. He was formerly president of Ruark Engineering, Inc., a company that provided analysis, recommendations and training for clients worldwide that manufacture industrial ceramics. He can be reached at (412) 788-7100 or rruark@swindelldressler.com.

Related Articles

Kiln Connection: Always Question the Data

KILN CONNECTION: Tunnel Kiln Killing You?

Kiln Connection: Making the Connection

KILN CONNECTION: Connection Lost

Related Products

Ceramic Industry Data Book and Buyers' Guide

Ceramic Industry July 2018 Data Book & Buyers' Guide

Ceramic Industry December 2018 Issue

Ceramic Industry Equipment Digest

You must login or register in order to post a comment.

Report Abusive Comment

Subscribe For Free!
  • Print & Digital Edition Subscriptions
  • eNewsletters
  • Online Registration
  • Customer Service

More Videos

Events

January 1, 2030

Webinar Sponsorship Information

For webinar sponsorship information, visit www.bnpevents.com/webinars or email webinars@bnpmedia.com.

View All Submit An Event

Products

Handbook of Advanced Ceramics Machining

Handbook of Advanced Ceramics Machining

Ceramics, with their unique properties and diverse applications, hold the potential to revolutionize many industries, including automotive and semiconductors.

See More Products

Ceramic Industry Magazine

01_CI0519Cover-144px

May 2019

What can Ceramics UK attendees expect to see? Find out in our May issue, and learn about brazing, zirconia structural ceramics, waste heat transfer, and more!

View More Create Account
  • Resources
    • Advertiser Index
    • List Rental
    • Classifieds & Services Marketplace
    • Manufacturing Group
    • Partners
    • Want More?
    • Connect
    • Privacy Policy
    • Survey And Sample

Copyright ©2019. All Rights Reserved BNP Media.

Design, CMS, Hosting & Web Development :: ePublishing