A. The action of the injector is due first to the difference between “kinetic” or moving energy and “static” or standing energy; second, to the fact that steam at a pressure travels at a very high velocity and when placed in contact with a stream of water it is condensed into water, and at the same time it imparts enough velocity to the water to give it sufficient momentum to overcome a pressure even greater than the original pressure of the steam.  By imparting this velocity to the water it gives it sufficient energy to throw open the check valves and enter the boiler against high pressure.

50.  Q. What is the difference between a lifting and a non-lifting injector?

A. A lifting injector will create sufficient vacuum to raise the water from the level of the tank.  The steam tubes in a non-lifting injector are different and it will not raise the water, but merely force it into the boiler.  A non-lifting injector must be placed below the level of the water in the tank so the water will flow to it by gravity.

51.  Q. Will an injector work with a leak between the injector and tank?  Why?  Will it prime?

A. A lifting injector will not work if the leak is bad.  It will not prime because the air admitted through the leak destroys the vacuum necessary to raise the water to the injector level.  A non-lifting injector will work, as the water will escape from the pipe instead of air being drawn into it as with the lifting injector.

52.  Q. If it primes well, but breaks when the steam is turned on wide, where would you look for the trouble?

A. Insufficient water supply due to tank valve partly closed, strainer stopped up or tank hose kinked, injector tubes out of line, limed up, or delivery tube cut, or wet steam from the throttle.

53.  Q. If it would not prime, where would you expect to find the trouble?

A. Insufficient water supply, priming valve out of order, or with the lifting injector the trouble might be caused by a leak between the injector and tank.

54.  Q. Will an injector prime if the boiler check leaks badly or if it is stuck up?  If the injector throttle leaks badly?

A. No.

55.  Q. If steam or water shows at the overflow pipe when the injector is not working, how can you tell whether it comes from the boiler check or the injector throttle?

A. Close the main steam valve at the boiler, that will stop the leak if it comes from the injector throttle.

56.  Q. Will an injector prime if primer valve leaks?  Will that prevent its working?

A. It will prime, but not as readily as with priming valve in good condition.  This will not prevent its working, but it may waste some water from the overflow.

57.  Q. Will an injector work if air cannot get into the tank as fast as the water is taken out?

A. No.

58.  Q. If you had to take down a tank hose, how would you stop the water from flowing out of the tank that has the syphon connections instead of the old-style tank valves?