Another Injector question . . . .

[GWRdriver]

Let me pose a question . . . making the assumption that it's important that injector bodies be kept cool, has anyone seen an injector actually located within a loco tank? In other words, immersed in its supply of water?

In the application I have in mind the water supply (In the tank) can be kept cool by recirculating fresh water from the tender, the water supply would be drawn directly from the water surrounding the injector (through an appropriate filter screen) , and the steam in, overflow, and supply out will be via say O-ring glands in the tank walls.

I can't say that I've ever seen this or heard of it, and thus it's far-fetched on the face of it, but I have a project where injector space is virtually non-existant, and needs must . . .

[waggy]

Hello Harry,

A friend of mine tried this as an experiment on a freelance tank loco he built. It worked but he found the overflow steam and the steam feed warmed the feed water very quickly. He got partially round this by running the overflow through a pipe vented outside the tank, the heat from the feed pipe remained a problem. He eventually reverted to "normal" mounting, I don't know why though. He is no longer with us so can't be asked!
Having the injector in the water certainly does away with water feed pipes and there's no danger of drawing air in with the water.

Good luck,

Waggy.

[GWRdriver]

Waggy,
That's encouraging. In dreaming all this up I kept in mind the need to keep all cool so I'd planned on incorporating an arrangement whereby cool water from a tender could be recirculated as required. My feeling is that cooler water could be recirculated faster than the injector and overflow could warm it up.

This is not a "done-deal" yet . . . I'm mulling over the options. I simply have no usable free space over the footplate level or I wouldn't consider it. I could put it behind a side tank, but then it would be next to the firebox with no way to keep it cool.

[eightpot]

Having once been thrutched from behind by another loco because it's driver/owner was more engrossed in trying to get his injector to work rather than looking to see what was in front of him, I'll remain biased in favour of pumps.

[Shawki Shlemon]

Hi all
I think the basic principal of this idea is sound, the only problem I see is that the water quantity is limited and soon will all be hot and the purpose will be defeated .

[Laurie_B]

I'd agree with Shawki that the water in the side or saddle tanks of miniature locos soon warms up.Better to have the injectors 'in the open' as it were.Easier for maintenance access too,as injectors can be a bit troublesome at times.

Incidentally,some condensing tank locos,such as the GWR Metro,633 and 9701 classes and the Metropolitan Railway Beyer Peacock locos ('A' Class?) had dump valves fitted to the water tanks.The condensing steam entering the tank warmed the water to a degree where problems were encountered with the injectors.The water tanks would be emptied at designated locations and then refilled with fresh,cold water.

[waggy]

Harry,

A thought occurs! (Rare thing, my thoughts!) Do you plan to let the water circulate and cool the tanks and then go to waste or have you some sort of "closed loop" in mind?
If the water is going to waste, you could place the injector next to the firebox and leave a trickle of cold water running through it to disperse any heat absorbed.
If you are recirculating, could you fit a cooling jacket to the injector and still position it next to the firebox?

Waggy.