Steam & Excursion > Non-Lifting Injector Question

I've never worked with one.  Is it necessary to turn off the tender water supply and/or the overflow valve when not running the injector?

-LD

LarryDoyle Wrote:
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> I've never worked with one.  Is it necessary to
> turn off the tender water supply and/or the
> overflow valve when not running the injector?
>
> -LD

I believe it depends on the brand & model of the injector. For example, SP 4449 has a Nathan 3750 non-lifting type, and there are two separate controls for the Fireman; 1) water supply and 2) overflow, in addition to the main lever operated steam supply. Thus, the water supply valve is kept closed (off), while the overflow valve is kept open. Thus, when the need arises to use the injector (which is also on the Fireman's side along with the Worthington SA Feedwater pump control), the water supply valve is first opened, then the lever is pulled on to prime, and then fully on for steam supply to the injector. Rarely is the overflow valve closed, unless one needs to "force" the injector to pick-up all the water. The water supply valve can also be used to throttle down the amount of water being supplied to the boiler.

Conversely, the Nathan 4000 series non-lifting injectors have only a main water supply valve, in addition the the main lever operated injector control, which shuts off the water supply internally when the injector is shut down. The lever on the Nathan 4000 series, first "turns on" the water, then the next position primes & picks-up the water, and lastly there is a "MIN" and "MAX" positions on the quadrant which holds the lever. Thus, the main water supply valve can remain "on" throughout the day's operation.

For what it's worth, the more modern, larger steam locomotives on the SP, have ALL the water controls on the Fireman's side, thus allowing the Engineer to concentrate on "running the train". On the GS series of 4-8-4s, the Fireman even has the headlight and Mars Light controls. On the other hand, the UP more modern, larger steam locomotives, have the non-lifting injector mounted on the Engineer's side, while the Fireman has the feedwater system controls, whether the Elesco Exhaust Steam Injector, or the Sellers Exhaust Steam Injector, or the Worthington S Feedwater System.

And what happens if the water supply and overflow are both closed with a leaky boiler check, he asked.

Out

callum_out Wrote:
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> And what happens if the water supply and overflow
> are both closed with a leaky boiler check, he
> asked.
>
> Out

The injector gets hot. That's why the overflow valve is supposed to ALWAYS be open.

Jack, we all know what's supposed to happen, injector not only gets hot but there's also a subsequent pressure rise in the injector body.
So, slight chnage of subject, looks like this is the last year for the Midwest O Scale Meet, last chance to find a vendor with scale injectors
for sale.

Out 

The Hancock Non-lifting Inspirators we had on the narrow gauge were capable of being trimmed back to almost nothing.  With a light to moderate train westward from Antonito where the ruling grade was only 1.42%, one could trim the gun back to where it was run continually.  These injectors had a closed overflow system and the water regulation was by a valve on the starting valve which controlled the amount of water admitted (I honestly never figured exactly how it worked, just that it did).  With a closed overflow, the water was always "on".

Locomotives 497 and 463 had lifting injectors and these would be trimmed back to just where water would begin to trickle out the overflow.  Even then, they would eventually fill up the boiler.  The program was run the injector until the water was about 7/8 of a glass, let the fire die down and the steam began to drop, then turn the injector off and fire very lightly, keeping the grates covered.  When the water got back down to about 1/2 a glass, build the fire back up and before the pops lifted start the gun and trim it back again.  You'd have to to kill the injector and let the water back down about every 30 minutes or so.

The Sellers-replica injectors made by Strasburg could be trimmed back quite a ways, but not as far as the Hancocks.  They were open overflow, so when not in use, the water valve was closed.  At Strasburg, we ran with the water valve wide open.  the grades were short enough, that one simply cycled the injector on and off "trading steam and water" keeping a 5lb. range on the steam pressure.  On the SLRG in Alamosa, we would run the injector most all the time when working, trimming it back as needed.  You would trim it back until it started to spill out the overflow, then open it up a bit clear up the spilling water.



Edited 1 time(s). Last edit at 01/16/20 18:24 by Earlk.

What kind of water flow rate is injected with these injector devices?  That is, gallons per minute. I know it's variable, but flow must be tremendous to cool down the entire boiler.

Thanks

Illbay Wrote:
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> What kind of water flow rate is injected with
> these injector devices?  That is, gallons per
> minute. I know it's variable, but flow must be
> tremendous to cool down the entire boiler.
>
> Thanks

The Nathan non-lifting 4000 type injector has a maximum capacity of 12,000 gallons per hour.

Wow.  You could empty an entire Big Boy tender in about an hour.  Suspect No one would ever do that.
 

Be tough to evap 200 gpm, what would happen is that you'd cool the boiler to the point where you wouldn't be able
to make enough steam to make the injector work. that and death threats from the engineer. 

Out 

That's the whole idea.  You wouldn't ever want to be on an engine that's using steam faster than you could feed it water.

-LD

Illbay Wrote:
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> Wow.  You could empty an entire Big Boy tender in
> about an hour. 

Not quite, as those big UP pedestal tenders hold 25,000 gallons of water.

Suspect No one would ever do
> that.

Actually, that is what the Elesco Exhaust Steam injector is for, when climbing Sherman Hill westbound, with a full tonnage train, at about 20 MPH. With a roaring hot fire, at full throttle, ascending track 3, the 4000 class locomotives required additional coal & water at Harriman, so just figure how much coal & water was used in over an hour or two.

Typically, modern engine crews only used the gun for rare instances...mostly, to keep the safeties from lifting.
"Back in the day", safeties going-off was a First Class Sin committed by engine crews.

Always to be avoided at all costs...

Mostly, if crews wantonly allowed safeties to be blowing...at numerous terminals across a system...
the CumulativeCosts of the wasted energy released in the fire ( by too much coal) could amount to a
sizable amount of cash...over an annual accounting period.  
So, RRs  were RIGHT to have policies directed at promoting No Smoke & No Safeties Rules & Regs.

​W.

How is an "Exhaust Steam injector" used?   Does it increase firebox draft?

Thanks

Illbay Wrote:
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> How is an "Exhaust Steam injector" used? 

It is simply an "injector" that has the capability of using exhaust steam to pre-heat the feedwater, instead of boiler steam. If there is insufficient exhaust steam, then the "change-over valve" inside the injector assembly, uses boiler steam to pre-heat the water.

 Does
> it increase firebox draft?

No. No injector can "increase firebox draft"


> Thanks

wcamp1472 Wrote:
-------------------------------------------------------
> Typically, modern engine crews only used the gun
> for rare instances...mostly, to keep the safeties
> from lifting.
> "Back in the day", safeties going-off was a First
> Class Sin committed by engine crews.
>
> Always to be avoided at all costs...
>
> Mostly, if crews wantonly allowed safeties to be
> blowing...at numerous terminals across a
> system...

Cavaet: Every locomotive must have at least two safeties.  The one with the lower setting must be blown at least once every day and its release and its reset pressures recorded on daily report.

For every minute a safety valve is blowing apx 15 pounds of coal is wasted.  That's 15 pounds you wouldn't have had to shovel.  One shovelful.  Put another way, at $200.00 per ton that's $1.50. 

If I find a green fireman who "doesn't get it", I've taken a tin can and set it on the smoke shelf, put a dollar in it and told the student he had to add a dollar every time the safety blows, the money going to the Museum's Steam Fund.  They'll catch on.

-LD



Edited 2 time(s). Last edit at 01/20/20 06:19 by LarryDoyle.