About six years since, a new copper boiler of one of the ferry boats plying between New York and Pawlus Hook, New Jersey, burst in consequence of the safety valve having been fitted too neatly, so that when heated by the steam it expanded and stuck. The boat had made several trips during the morning, and no steam had been observed to pass off for several hours.; The boiler was turned upside down, and flat tened.
In another boat, on the Delaware, the escape pipe for the safety valve was of a conical form, the great est diameter of which was below, so that when the valve raised, it closed the pipe, and prevented the steam from passing off. The defect was, however, observed, and an explosion prevented.
Explosions from overloading the safety valve have frequently occurred. The evidence of Mr. Richter before the committee of the House of Commons, p. 122, proves that the dreadful explosion of the sugar refinery in Wellclose Square, London, se veral years since, was owing to this cause. The engineer, being informed that the engine did not work well, put an immense weight upon the lever of the valve, so as to render it. useless, still urging the fire, and in a few minutes it exploded, and blew the whole house to pieces. The same cause, according to Mr. Legit, produced the explosion in the tobacco manufac tory at Chester, England, in July, 18224 Aragol mentions that from this cause the boiler of the steam-boat Rhone exploded on the 4th March 1827, and killed several persons. " Vexed at not be ing able to overcome the rapidity of the current as completely as he had hoped, the engineer fastened down the safety valves of all the four boilers ; three of them burst almost simultaneously.
Another case occurred in a boiler attached to a wa gon in Sunderland, England, by which several were killed.§ The Norwich (English) steam-boat exploded in part from the same cause. The attendant engineer seated himself on the safety-valve, in order to give his com rades the spectacle of the oscillating motion that he would undergo, as he said, as soon as the vapour should become strong enough to lift him. The valve did not open, but the boiler burst, and killed and wounded a great number of persons.
Arago quotes another case, of a steam-boat on the Ohio (name not mentioned), in which the explosion took place while the crew were engaged in weighing the anchor ; when there was no consumption of steam, although the fire had attained its full force, and the safety valve was loaded with additional weight.
In 1803 the safety valve of a high pressure boiler in England, was fastened down by a boy, with a piece of timber, and rendered entirely useless for some time ; and then the engine was stopped by another workman, who knew nothing of what the boy had done. Shortly after the boiler burst.11 Several accidents have happened in the United States and other places, in boats from these causes. The rash conduct of the engineers or firemen was excited from an anxiety to beat other boats bound to the same places. All the particular cases in the United States cannot be mentioned, but they were stated at the time in the newspapers.
3. Original Weakness of the Boiler.
In the account given of the explosion of the United States steam-boat, September 1830, on the East River, New York, it was stated that in nearly all the accidents that have occurred in the New York waters, the rup tures have taken place in the same part of the boiler. In the Constitution, Legislator, Bellona, Chief Justice Marshall, and the Carolina, all low pressure boats, the rents were made in the lower part of the flues. In these boats there were no braces between the flue and the outer shell in the bottom of the boilers. The Constitution after her accident had them put in, and no explosion has since taken place. The United States boat, when the explosion happened, was going at her usual speed, with 122 inches of steam, as had been as certained two minutes before by the captain, who ex amined the guage. The boat could carry 13 inches of steam, and the boiler was so fixed that the steam j blew off at 14 inches. The engineer had also just fore examined the water cocks, and found that there was a sufficient supply of water. The part that gave way, viz. the lower part of the main flue, ten feet back of the bridge wall, had been repaired about a week before the accident, and four sheets of iron put into the flue. These were torn away, but the rivets re mained in the old sheets. The boiler was of sheet iron of a cylindrical form, 22 feet long, and 8 feet in diameter, with what are called " kidney flues," form ing one large cylinder, and one return flue; and had been nine years in use.* 4. Use of Internal Flues.