LEEDS AND NORTHRUP SPEEDOMAX 'H' CHART RECORDER, 1960's

Valve chart recorder, for measuring and recording on paper information collected by sensors sensitive to voltage or current readings, meaning it could record almost any equipment with a sensor attached to it.

Your comments:

• Used at Cleveland-Cliffs (formally Inland Steel Company East Chicago, IN) all Hot Metal Shops to measure molten steel temperatures using "Electronite" Expendable thermocouples which are specialized sensors design for one-time temperature measurements in molten metals, such as steel or iron. They consist of a thermocouple element housed in a protective ceramic and cardboard tube, which is dipped into the melt to provide and accurate reading before being discarded. Note: the recorder times out and alarms when the peak temperature is reached. Also the temperature calibration table used to purchase, the temperature recorder and thermocouple must all be based or matched to the same ITS or IEC Standards used by the Metallurgical Department when they created the melt formula. 1960-1997 we used the ITS-49 calibration table (ITS-90 table is 10 degrees different for Platinum Type S Pt/Pt-10% Rh thermocouple's)
  
  .......... Teddy L Timmons, Reynoldsburg, 13th of April 2026
  
  
• I used to have to sometimes fill one of these up with ink. It was a terrible job! If you got the ink on your hands it took days to wash off. If you got it on your shirt sleeves - well, just forget it, the stains would NEVER wash out.
  .......... Richard, Reading, 9th of August 2010
  
  

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