IMPROVEMENTS IN STEAM NAVIGATION. SYMINGTON'S IMPROVED CHAPTER I. METHOD OF CONDENSING BY INJECTION, TO PREVENT INCRUSTATION; BY WHICH GREATER DURABILITY OF THE BOILERS, FREEDOM FROM EXPLOSION FOR WANT OF WATER, AND A SAVING IN FUEL OF NEARLY ONE-THIRD, ARE ENSURED. THE incrustation of boilers of marine engines has been long acknowledged one of the greatest drawbacks to Steam Navigation, and the many evils arising from it, whether in impure river water, or at sea, are too well known to require minute description. In river steamers, where the water holds in solution, mud, chalk, lime, or other impurities, the wear of the boilers, owing to the depositions, is scarcely less rapid than in sea-going vessels. But in these in particular, the loss of power from blowing out, frequently every four or five hours; the dangerous injury done to the boilers, if omitted through carelessness or design; the useless expenditure in fuel, to heat the great quantity of water thus wasted; the valuable space occupied by nearly one-third more coals than would otherwise be required; the loss of just so much freight; together with the detention of the vessel, taking up her decks, docking, and incidental heavy charges for repairing the boilers, owing solely to this cause; the constant annoyance of blowing, and chipping, and cleaning them; and the rapid destruction of the boilers themselves, even under the most careful engineers, render the present system of Steam Navigation open to great improvements, besides forming considerable deductions from the profits of every Steam Shipping Company. The removal of all these annoyances; the absence of all doubt whether the boilers will last another, or another, or another voyage, each time the vessel returns; the serious loss or injury that may arise to a Company, if the judgment should be found erroneous in this respect; economy of space and fuel; the durability of the boilers, and the certainty of no danger from undiscovered incrustation or want of water, are objects of the first importance; and whatever will, in a simple, durable, and effectual manner, produce these results (without originating other disadvantages) must, certainly, be considered an important advance towards perfecting this vast agent of extending British commerce and communication. The inventor, the son of the late William Symington, the originator of Steam Navigation, is encouraged to believe that he has devised a remedy for these evils, simple and cheap in its application, taking up no room, adding nothing to the tonnage of the vessel, and perfectly efficient in its operation. It appeared to him not a little singular, that so many attempts should be made to condense inside the vessel, by means of ponderous tanks, occupying valuable space, and which, at the best, must be but imperfect coolers, when there was so simple and perfect a condenser outside, as the open sea or river. Following up this happy, though bold idea, he could entertain no doubt that, by cooling down the water in the hot well to the temperature of the external water, by means of pipes so placed outside the vessel as to receive the direct action of the water, in order that condensation might be effected by injecting, again and again, a portion of the same water, while the remainder was returned to the boiler, he would succeed, more especially as such a plan would involve no alteration in principle, in producing a very simple and perfect mode of preventing incrustation, applicable, with admirable facility, to any vessel, in a few days, and without making any alteration in the engine itself. By his method, the injection water, after condensing the steam, is conveyed in the usual manner by the air-pump into the hot well, from whence a portion of it, instead of being wasted, enters the refrigerating pipes outside, so placed as, in any rolling or pitching of the vessel, to be considerably beneath the line of flotation; and, by the rapidity with which they are brought into contact with the constantly changing particles of water, by the motion of the ship, every portion of warmth is speedily given out; and, before the water completes its passage to the condenser, it becomes of the same temperature as the external water, and ready for injection again. The remaining portion of the water escapes to the boiler by means of a float in the hot well, which moves on friction rollers, in front of the orifice leading to the feed-pump, and rises and falls freely with the rise and fall of the water in the hot well. By this simple means, the supply and circulation of the blood in the body can scarcely be more regularly adapted to the calls upon it, than the supply of water to the boiler is in exact proportion to its wants and the speed of the engine. Only the precise quantity of injection water and condensed steam, that is necessary to supply the deficiency in the condensing pipes, for the purpose of injecting again, will find its way in that direction, (for they can but be full,) whilst the residue, which is also the precise quantity of water evaporated and condensed at each stroke of the engine, will find its way into the boiler by means of the feed-pump; and thus, by keeping the water always at the same height, remove the serious danger arising from the carelessness of engineers neglecting a proper supply. The steam from the safety |