MORE BOILER EXPLOSIONS


| March/April 1982



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106 South Elm Street, Newkirk, Oklahoma 74647

Boiler explosions are caused by many things other than low water. Deterioration that occurs while standing idle causes many of these tragic accidents. The place where this can do the most harm is along the longitudinal seam of the barrel.

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This writer owned and operated boilers for many years in a state that had strict boiler laws and inspection every year. During this time I became acquainted with several inspectors. They told me of two explosions that had occurred from rust along the long seam. They explained the cause. Some of the boilers used on traction engines had the lap joint seam down on the lower side with the edge of the inside sheet turned upward. Changes of temperature causes metal to 'sweat.' This means condensation will form moisture that will run down into the little trough at the top of the inside sheet. This makes an ideal condition for rust to form, and often the metal will be thin as a razor blade at this critical point. If the seam is on upper quarter, that is near the top of the barrel, there will be no little troughs either inside or out. Butt- strap joints should be located on the upper quarter of the boiler shell for the same reasons.

Other things also cause explosions. I once knew an elderly man who walked on a crutch. He had survived an explosion. I knew his son well and he told me how it happened. He said his father was firing a boiler for a sawmill. It was built with a good air-tight ashpan. He made a practice of filling his firebox with green wood, and closing the heavy draft door so he would have a good fire after they came back from dinner. One day as they quit for noon, the blocksetter wanted a light for his pipe, so he raised the door, got a live coal, propped the door up with a stick and forgot to close it.

Now there were other things that were wrong with the equipment. The boiler was fitted with an old weight lever safety valve that had a bevel seat. These were outlawed many years ago. This valve would stick fast in the worn seat sometimes, but Mr. Shackelford (I don't remember his first name), would watch it very carefully and raise it when it stuck.

When they got back from dinner, the fire was blazing hot, and the pointer on the steam gauge was clear around resting on the back of the pin. They all yelled 'let's get from here,' and ran as fast as they could except for the dumb block setter whose light for his pipe had caused the trouble. He ran by and kicked the prop from under the draft door. When this heavy iron door fell, the jar did it-- the boiler let go as though it had been filled with dynamite! They picked the block setter up in a basket. The rest of the crew were all hurt, and Mr. Shackelford walked on crutches for the rest of his life.