How to start the injector when the water flows to it.-Draw the steam-tube, B, nearly all the way back, by revolving the handle, M, which actuates tube, B (same as the wheel does the valve in a common globe-valve), and pull lever, M', all the way back. Open steam-valve a little, to clear pipe of condensed water; when steam blows out at overflow, push lever, M', full forward, open steam full, and open water-cock. When water runs solid from overflow, draw lever, M', slowly all the way back, and turn in tube, B, slowly till water ceases. The injector is then set to feed its maximum amount at the pressure of steam then used. It may then be started by simply opening steamvalve a little, as above, to clear the pipes; then close steam- and open water - cocks. When water runs solid at overflow, open steam-valve slowly, and feeding will commence without operating lever, M'.

How to start the injector when the water is to be lifted. -Draw steam-tube, B, nearly all the way back, and pull lever, M', all the

To BOILER

way back; open steam-valve a little (or all the way, if desired), to clear steam-pipe, and, when steam appears at overflow, push lever, M', full forward-the water-pipe being open, water will be likely to appear at once (or in a few seconds) at overflow; if not, pull lever, M', back a moment to clear the injector and push full forward again. As soon as the water runs solid at overflow,

pull lever, M', slowly all the way back, and screw in tube, B, until feeding commences. It is then feeding the maximum amount at pressure. It may then be started by turning on steam; push lever, M', full forward, and then pull back as above, when water appears at overflow.

To reduce the feed in either case. When the injector is set as above, push lever, M', forward, until water begins to run from overflow; then cut off water with handle, M, until it ceases at overflow, and repeat as long as it will bear, and continue to feed. The minimum feed is thus obtained, and the water is delivered to the boiler the hottest.

There is one principle that governs the action of all injectors. which is, that if the temperature of the water is raised too high they will not work. Some injectors will lift water as high as 20 feet, according to the temperature of the water and the size of the injector; large injectors having invariably the greatest lifting e pacity. As the amount of water thrown depends on the velocity

of the steam, it follows that the volume of water thrown will be much greater with high than with low steam-pressure.

The annexed cut represents Mack's Fixed-Nozzle Injector, which is said to have a working range, with one handle, of from 15 lbs. to 175 lbs. steam-pressure per square inch, and is always reliable, whether worked con

stantly or once in a year. When extraordinarily high pressure is required, an extra valve is attached, which will admit of working this injector at a range of 5 lbs. to 250 lbs. per square inch.

Fixed - Nozzle Injectors have no movable or adjustable parts within them; they STEAM can be regulated by steam-and water-supply cocks on the outside of the instruments; but there is one pressure of steam to which they have been primarily adapted, and at which they work best, viz., at the pressure at which they give the largest duty. Inasmuch as the pressure of steam in stationary boilers is, as a rule, held constant, they are well suited for that kind of work; but in cases where there is a great variation of pressure they are not so well suited.

Mack's Fixed-Nozzle Injector.

There are fewer of them in use than of other arrangements, nevertheless some of them give satisfaction, but in any case their simplicity is their chief recommendation.

The Inspirator.

The inspirator, though belonging to the injector family, differs from the latter, inasmuch as it is a double instrument, consisting of a lifting and a forcing side; the latter being to all intents and purposes, with

slight mechanical variations, an "injector," while the former is a kind of a pump, which supplies the forcer side with water. The whole machine is a curious combination of mechanical arrangements for lifting and forcing water, and cannot be actually said to be either an injector or a pump, though it performs the functions of both. The inspirator is capable of lifting and forcing water or other fluids to a great height. It will lift water 25 feet, with a steam-pressure of 30 lbs., provided the suction-pipe be perfectly tight, and the instrument is furnished with dry steam; but the temperature of the water will control to a certain extent the height

of the lift. For a lift of 25 feet, the temperature of the water

Whenever the inspirator fails to act, the trouble, in a majority of cases, will be due to leakage in the pipes. Other causes are due

to the area of the suctionpipe being too small, which ought in all cases to be larger than the nipple or swivel to which it is connected; but in any case it is advisable to have a foot-or check-valve in the suctionpipe, below the level of the water in the well, river, or mine.

How to operate the inspirator. When steam is admitted to the inspirator, it passes through the lifter steam-jet, leaps the interval, A, through the combiningtube, and escapes at the overflow, thus expelling the air and producing a partial vacuum, into which the water rises. As soon as the water appears at the overflow, close valve No. 1, to prevent it from escaping, and induce it to pass up the forcer, and through the combining-tube B; then by open

ing the handle No. 2, and closing No. 3, the water is forced directly through the feed- or delivery-pipe into the boiler or tank, as the case may be. The inspirator is adapted as a boiler-feeder for either stationary, locomotive, or marine engines.