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Heater Failure
We spent a number of weeks discussing life factors for Watt-Flex® cartridge heaters. One contributing factor to heater failure is worth exploring further. The failure of an element is often due to the burning out or opening of the resistance coil. The coil is a winding of 80-20 NiCr wire. During the operation of the heater, the chromium diffuses out of the wire to its surface where it oxidizes. .
This process causes the heater wire to become brittle as a result of its much higher concentration of nickel.
Eventually it will work harden and open under stresses created by thermal cycling of the element. Higher heat will accelerate this process and it will certainly affect finer wire gages more quickly. |
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In addition to a date code on the heater, the state of the wire is a strong indicator of the life that the heater has seen. Returned heater dissection that reveals very brittle wire as compared to its original supple state, tells us that the application is very high temperature or that the heater has seen significant life. One other scenario is that a poor fit in the bore prohibits effective heat transfer, causing a severe over-heating of the resistance coil.
Friday Funnies
Interesting Body Facts
- A full bladder is roughly the size of a soft ball.
- It takes the food seven seconds to get from your mouth to your stomach.
- One human hair can support 3 kg.
- Human thighbones are stronger than concrete.
- The attachment of human muscles to skin is what causes dimples.
- Your thumb is the same length of your nose.
- A woman's heart beats faster than a man's.
- If the average male never shaved, his beard would be 13 feet long when he died.
- Men without hair on their chests are more likely to get cirrhosis of the liver than men with hair.
- There are about one trillion bacteria on each of your feet.
- Side by side, 2000 cells from the human body could cover about one square inch.
- Women blink twice as much as men.
- The average person's skin weighs twice as much as their brain.
- When you are looking at someone you love, your pupils dilate, they do the same when you are looking at someone you hate.
- It takes twice as long to lose new muscle if you stop working out than it did to gain it.
- You're ears secrete more earwax when you are afraid than when you aren't.
- Your body uses 300 muscles to balance itself when you are standing still.
- If saliva cannot dissolve something, you cannot taste it.
- The average woman is 5 inches shorter than the average man.
Side Note:
You checked out the length of your thumb.. Didn't ya ???
Yes you did, you know you did.... admit it !!
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