Friday, May 11, 2018

"BOOM" Goes The Boiler

So I am in a gabby mood today and what better place to get long winded (hey I do it seldom enough).

Boiler explosions in the 1800's and early 1900's were a common occurrence. When I was working at the co-gen mentioned in a previous post, the next town over had a sawmill with an old riveted boiler supplying steam for heating and their dry kilns. Yes, it was in the regional news that it blew up. Fortunately no one was hurt.

I found a great article on the causes of boiler explosions in an old PM Shop Notes and since I operated boilers for over 25 years, it was of interest to me and hopefully others here.

Steam technology would have advanced much quicker if not for the difficulty of producing boilers capable of operating at high pressure. Until well into the 20th century boilers were built with riveted construction. As shown in the article, this presented some problems at higher pressures. Most boilers were of the firetube type with large drums (similar to a locomotive boiler). Pressures were limited to around 150 psi. Watertube boilers with smaller drums were being developed and some of these operated as high as 300 psi. Modern watertube boilers for use in generating power plants have large 1 piece drums that can run 2" thick and operate at pressures over 1000 psi. This has it's own problems like, " Where the hell is the water level" lol, (water and steam have the same density at these pressures) but they are easily worked around with todays tech.

Before I retired I had worked in 7 power plants. 1 of these plants still had 3 riveted boilers. But first here is the article.

The second plant that I operated was the Port Arther Shipbuilding power house. This plant was built in the early 1900's, ships for the 1st WW were built here. The company owned the "Pascal" boiler patent on the riveted boilers I operated and they were the same boilers they had installed in the early ships they built. The boilers originally operated at 150 psi but due to their age we only run them at 75 psi. At that age, and still running, a testament to good water treatment. They had been originally fired on coal but had been converted to gas burners some years before.

As seems to be the trend, the last time I was in Thunder Bay the huge site was leveled and fenced off. All those hundreds of tons of vintage machinery shipped to China for melting no doubt.

The site had a huge foundry capable of casting a 6' X 18' paper mill roll and a large machine shop capable of machining it. Pattern making and storage was a large two story building with some truly awesome pattern making machinery in their. The boiler shop could roll huge sheets of 1" plate and had a large riveting tower. There was a blacksmith shop, no longer used, but it was like it had been shut down yesterday, everything still in it's place. In addition there was a large woodworking shop for doing ship interiors, I saw more than 1 huge mountain of iron that were 36" and 48" planers. The dry dock could handle vessels up to 900 ft., (the big lakers) and the steel prep and welding building in front was just as long. Full ships patterns could be laid out, on the open second floor.

In the power plant the 3 - 300 HP AC to DC converters that supplied power to the dock cranes and pumps and  the electric furnaces in the foundry, had 1898 patents stamped on them. A shame to see all this technological history scrapped.

So back to the articles. I had my 3rd class license at this early stage. To operate the largest plants I needed my 2nd class license so I spent my night shifts studying for the exams. Thats good because otherwise I would have had to build this Rube Goldberg machine to stay awake, lol.

Cheers All