INJECTOR.
An Injector is an automatic machine attached to a boiler, for injecting or forcing water into it and at the same time heating the water to a very high temperature, which saves fuel and prevents the danger of sudden contraction of the plates and flues. It can be used independently and is indispensable on a farm engine.
In piping an injector to boiler, use as short and as straight pipes as possible and especially avoid short turns. Take steam directly from boiler, and have a globe valve in steam pipe close to injector; have the water suction or supply pipe independent of any other connection, and it must be supplied with a globe valve close to injector. This pipe and connections must be absolutely air tight; the slightest leak will cause trouble. The discharge pipe to boiler must be supplied with a tight and reliable check valve. If valve leaks, the injector will become hot and cause no end of annoyance. It is a good plan to put a stop valve between check and boiler in discharge pipe, so that check valve maybe taken off and repaired, or a new one put on without loss of time. A foot of straight pipe screwed into the overflow assists in starting an injector, especially at low pressure.
American U. S. Injector.
Q. How do you start an injector to work?
A. To start an injector, open the suction valve wide, then open steam valve. If water appears at the overflow, close and open quickly the suction valve, opening only about ¼ of a turn if at low steam pressure, and one turn or more if at high steam pressure, regulating the water supply according to steam pressure. The injector is controlled entirely by the valve in suction pipe, or by the suction lever after the steam is turned on.
Q. Will an injector work with hot supply water?
A. An injector will not work if the water that is delivered from the tank is too hot to condense the steam.
Q. What are the principal causes of an injector not working accurately?
A. Leak in suction pipe, supply cut off by strainer being clogged, loose lining inside the hose, leak in the stem of valve, too little steam pressure to lift, dirt in the tubes, red lead blown or drawn in through steam or supply pipe, bad check valve, not lift enough or none at all, new boiler full of grease, wet steam, obstruction in the connection to the boiler.
If injector fails, examine at all of these points before condemning. The most common trouble is a leaky suction.
In describing the method of connection and operating an injector the foregoing may have to be modified in some instances, as there are a great many different kinds and styles of injectors which operate and connect differently, but the above if followed carefully and with a little discretion will be found useful.
Bear in mind, however, that the injector does not start to work to boiler as soon as it gets the water. At first the water will run out of the overflow. At this point you start the injector working to the boiler by closing and opening the water valve as quickly as possible with a jerk, or as nearly with one motion as you can.
Q. How do you find the maximum and minimum capacity of injectors?
A. Injectors are controlled entirely by the suction valve after steam is turned on. To find the maximum capacity of an injector after starting, gradually open the suction valve in supply pipe until steam “breaks” and water comes out of the overflow, then start the injector again and you will know about how far the suction valve can be opened without causing the “break.”
To find the minimum capacity of the injector, manipulate the suction valve in the same manner in exactly the opposite direction.
DIRECTIONS FOR OPERATING
WORLD INJECTOR.
See that the injector is shut off when put on, by turning the handle as far to the right as it will go. To start, turn handle to the left one-quarter turn; when the water appears at the overflow, turn the handle slowly to the left as far as it will go, and the injector will be working to the boiler.
American World Injector.
If steam is high and lift long, the injector will lift the water better if the handle is turned a little less than a quarter of a turn, until the water appears at overflow—then start to boiler as before.
If you have valves in steam and suction pipes, be sure and open them before starting.
Q. How high will an injector draw its supply?
A. About twenty feet is the limit.
Q. How hot does an injector deliver water?
A. From 150 degrees to 200 degrees, according to the steam pressure and the proportions of its capacity at which injector is working.
Q. How should the jets be cleaned when they become scaled?
A. By soaking in diluted muriated acid, about one part acid to ten parts water.