Ever seen an injector cut in half?

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cbrew
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Re: Ever seen an injector cut in half?

Post by cbrew »

philbert wrote: Thu Apr 26, 2018 6:16 am
Fred_V wrote: Wed Apr 25, 2018 7:49 am here is one of the English ones in section.
Which side is goes to the boiler? And what holds the ball down in the top? Vacuum? Pressure? Dark wizards?!
must defiantly dark wizards :lol:
IMG_0817.jpg
If it is not live steam. its not worth it.
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DianneB
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Re: Ever seen an injector cut in half?

Post by DianneB »

Injectors are strange!

I KNOW how they work and have taught them in "steam school" many times. I can install them, troubleshoot them, and use them. I can prove they work (mathematically), but I look at them intuitively and think "That's shouldn't work!" How can you take steam at 100PSI, lift cold water at atmospheric pressure, and blow it back into a boiler against 100PSI pressure without any exhaust!

:shock:
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Fred_V
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Re: Ever seen an injector cut in half?

Post by Fred_V »

philbert wrote: Thu Apr 26, 2018 6:16 am
Fred_V wrote: Wed Apr 25, 2018 7:49 am here is one of the English ones in section.
Which side is goes to the boiler? And what holds the ball down in the top? Vacuum? Pressure? Dark wizards?!
From my cutaway the right side is the steam supply, bottom is water inlet, left is outlet. Ball is held by the vacuum created by the steam being condensed by the water coming in.
Steam is totally condensed so that only water exits the injector. The increase in mass raises the pressure above boiler pressure. If all the steam doesn't get condensed the ball doesn't seat and you get overflow.

The EE and Penberthy units work the same way but are more sophisticated and less picky.
Fred V
Pensacola, Fl.
philbert
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Re: Ever seen an injector cut in half?

Post by philbert »

So if you had a suitably small camera and light you could look up the overflow pipe and see a jet of water blasting across? That's pretty amazing physics
RET
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Re: Ever seen an injector cut in half?

Post by RET »

Hi,
Fred beat me to it.

The left side is the pressure recovery cone and goes to the boiler feed valve. The right side is the steam cone and comes from the boiler. The bottom connection is for the water supply. The middle cone (in two parts) is called the combining cone. In the top center is a ball check ( the ball is missing in the picture). In particular, the discharge line must be free from sharp bends, large enough to offer no flow restriction and the boiler check valve must open easily and offer no restriction to the flow.

In operation, turn on the water supply first, then the steam. You may have to throttle the water supply to get the injector to "pick up." Until the injector picks up, water and steam run out of the overflow through the ball check because the pressure in the combining cone is higher than atmospheric. When the flow fills the combining cone, it pulls a vacuum and the ball check seals off the overflow. If the ball wasn't there, air would be pulled in and it would destroy the efficiency of the injector. Good injectors will lift water four to six inches.

Logically this thing can't work, but thermodynamics says it has to, so it does. My hat's off to the original French engineer who came up with the idea (he wanted to use it in a balloon). The simple explanation is that it works because all the steam is condensed into water and that's why warm water doesn't work since some of the steam doesn't condense. The velocity inside these things is considerably above the speed of sound.

Richard Trounce.
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Fred_V
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Re: Ever seen an injector cut in half?

Post by Fred_V »

philbert wrote: Thu Apr 26, 2018 8:10 am So if you had a suitably small camera and light you could look up the overflow pipe and see a jet of water blasting across? That's pretty amazing physics
interesting idea, yes you could see it. probably just look like a solid rod.
Fred V
Pensacola, Fl.
rkcarguy
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Re: Ever seen an injector cut in half?

Post by rkcarguy »

It's a mechanical flux capacitor.
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Greg_Lewis
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Re: Ever seen an injector cut in half?

Post by Greg_Lewis »

rkcarguy wrote: Thu Apr 26, 2018 12:35 pm It's a mechanical flux capacitor.
Is that what's inside the turbo encabulator? Injectors use the same principle. Here's a link:

https://youtu.be/Ac7G7xOG2Ag
Greg Lewis, Prop.
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Fred_V
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Re: Ever seen an injector cut in half?

Post by Fred_V »

One of my favorites.
Fred V
Pensacola, Fl.
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Fender
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Re: Ever seen an injector cut in half?

Post by Fender »

AnthonyDuarte wrote: Mon Apr 23, 2018 7:37 pm Don't worry, no good injectors were harmed in the making of this cross section! This Small Scale injector body (#045) had a tumble and was deemed unusable.

I brought this "half sized" injector with me to Riverside and people seemed to really enjoy looking at it, so here it is for you to enjoy as well. A lot of work goes into these little buggers. If anything they're more difficult to make than the Standard injector.

-Anthony

IMG_0817.jpg
Hypothetical question: If you took this injector, rotated it 90 degrees to the right (or left), would it still work?
Dan Watson
Chattanooga, TN
philbert
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Re: Ever seen an injector cut in half?

Post by philbert »

Can't wait to have a crack at making an injector - steam fittings fascinate me
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NP317
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Re: Ever seen an injector cut in half?

Post by NP317 »

snip
Hypothetical question: If you took this injector, rotated it 90 degrees to the right (or left), would it still work?
No, because it is cut in half.
~RN
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