How An Injector Works

[Berkman]

A lot of steam launches do have injectors though right? I'm not very familiar with steam launch steam circuits, but don't they draw from the "cold well"?

[Bill Shields]

Or a feedwater condenser to bring the temp down

[NP317]

I only know about "Hot Wells": Recirculated boiler water after condensing from the engine exhaust and returned to the hot well, often above 150 degrees F. "Closed systems."
It's those high temps that injectors do not like.

There are "puffer" steam launches that do not condense and reuse the water: "Open Systems" exhausting to atmosphere. Water is taken from the lake/river for heating in the boiler.
Not good in salt or dirty water. Fine in fresh water, like the famous English Windermere steam yachts. (Worth looking at YouTube vids of them under way. FAST!!)

Condensing systems have varying degrees of resulting vacuum and heat returned to the boiler. Power through the cylinders = steam pressure + vacuum. A nice gain. Nice energy conservation in the system.

My steam launch has gravity feed (ON/OFF valve) from the fresh water "make-up" tank, that can replenish the hot well contents to maintain water level for feeding the boiler.
Water is lost from leaks and whistle blowing. Of course.
RussN

[Bill Shields]

Like a radiator on the outside of the boat that circulates water out to be cooled and back in to be used

Probably not a practical idea. I do not know much about small boat systems.

Steam donkey pump probably better solution...although an injector for backup using your makeup water as the supply would work for guggles.

[Berkman]

I think some steam launches do have a some sort of heat exchanger down the keel or a further system that pumps outside water through a heat exchanger in the "hot well" to cool the condensing water.

Injector as Bill said could be on the "make up" tank.

[Crosshead4]

You can “hear” the temp of the tender water in a sense. The warmer it gets the injector sounds less and less sharp. The delivery rate goes down and eventually it won’t work at all. Many tourist railroads fill the tender at the end of the day then put it in the engine house for the night. During a summer night the water would warm up enough to cause problems sometimes.
The next day I may have to use a couple thousand gallons then fill it back up with cold water. Would help a lot!

[Bill Shields]

Discovered while living in the Saudi desert that injectors will not run unless tender filled with ice cubes

[James Powell]

Discovered while living in the Saudi desert that injectors will not run unless tender filled with ice cubes

Hot enough that we hit full power parameters @ sea in the gulf...

28.3" Hg ME condenser = 100 F boiling point = sea temp of below about 95F to get there at full flow (16500 IGPM pump, or scoop inlet >40 RPM).

We still made something like 108 rpm on our way into the gulf, as fast as the old girl would hammer out. Not bad as we were heavy on, and probably had a wee periscope following us the whole way in . (108 = 21.5 kts by counter, probably more like 21 kts speed made good, and 21 000 shp indicated- I don't know what we were maxed' on, but I remember doing it at least once in 2002)

No injectors, or steam eductors on her though

Wild Wadi (the water park) in Dubai _cools_ the water in the pools...

[paralleler]

You can “hear” the temp of the tender water in a sense. The warmer it gets the injector sounds less and less sharp. The delivery rate goes down and eventually it won’t work at all. Many tourist railroads fill the tender at the end of the day then put it in the engine house for the night. During a summer night the water would warm up enough to cause problems sometimes.
The next day I may have to use a couple thousand gallons then fill it back up with cold water. Would help a lot!

Having a saddle tank locomotive, one of the first things I would learn is that an injector needed cool water. One day I noticed a little Rubbermade tub — that little tub has been in my riding car for five years now as I work other issues. The saddle tank still feeds water to the axel pump and a newly installed steam pump. With the help of several friends at the track, Harley is coming together.

[Fender]

I believe the other reason many modern locos had non-lifting injectors is that they could function using hotter water from the tender than a lifting injector could. Many engines with a feed water heater (usually on the fireman’s side) had an injector on the engineer’s side. With some feed water heater designs, excess hot water was returned to the tender, and the injector needed to be able to function with the heated water.