Non Lifting Injectors

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Mark D
Conductor
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Location: Sort of between Litchfield and Forest City, MN.

Non Lifting Injectors

Postby Mark D » Fri Jul 27, 2018 8:51 pm

Non lifting water injectors are often found on steam locomotives. In the case I am talking about the locomotive has two of them. Often, later steam locomotives had all sorts of gimmick’s to try to increase efficiency. I don’t think the non-lifting water injector is among those devices.
It is, however probably the most reliable device for shoving water into the boiler.

But even the non lifting injector can be subject to wear. There are no moving parts inside the injector body, but there are valves that wear out. It might seem that the internal parts wouldn’t wear because they don’t move. The internal parts consist of three ‘cones’. The steam come accelerates the speed of steam blasting into the injector, or basically increases the mass of the steam. This cone is the subject of this post.

Last winter a non-lifting injector started to become somewhat balky. It would work, then it needed an ever increasing gentle and precise touch to get it to work. I know full well because I ran into that issue when it started. Being all alone for the next 9 hours I used it, but decided to use the other injector most of the time because it was easier.

When my relief came up into the cab on the last night I was on the engine, I told him about the injector. He was a bit cocky and said it was me, he had been using it all week and it’s fine and that I probably don’t know how to properly prime it.
Ok, I wasn’t going to argue, but I’ve run that injector by a huge factor more than he has.

Fast forward a month or so, the engine had been in inside storage since the end of the day I got off in the morning.
As winter weather became slightly more mild the engine crew started in on the normal maintenance that would be needed before it could operate the next year. Inspections never end.
One item that had to be dealt with was the balky injector.
It turns out that someone – and I honestly don’t have a clue who did it because I haven’t been told – decided to remove the steam cone to try to see if the injector could be fixed.

Not being able do do much but look at it while the engine was out in the cold, doing a job, and few opportunities to putz with it nobody is going to be able to do much but fight with it.

However, that someone did damage to the threads inside the injector body, that are part OF the body, when they tried to screw the cone back in. The first three threads were crossed. This is fact.
I was chosen to clean up someone else’s mess.

The threads that were crossed are part of the body casting. They are about four inches down inside the injector body, which is a vertical body type.
My experience with threads told me that I couldn’t do anything with the damaged threads, but somehow we needed to do something to enable the cone to be replaced properly.

My solution was to make a special tool that could be screwed into the body from the bottom of the housing. This meant we had to remove the other cones first. No problem.

A couple weeks later I was back with my first effort on this. I had made a slug on a lathe that had about an inch of 14 pitch threads down about ¼ inch or so from the top of the 'slug'. Below the threads was just plain steel slug for a couple inches. I welded a ½ inch steel rod onto the slug and welded a 1/2" nut on the far end of the steel rod.
Once I had done that at home, I brought it to the engine and it worked out fairly well. The problem was that it didn’t work well enough. I could not get it into the crossed threads to either cut them or shove them back into place.

The injector body is a bronze casting, by the way.

I took the thing home and cut three slots across the threads on the slug and angled the ends so they could cut.
In the meanwhile a 2 inch by 14 pitch thread tap had been ordered to cut through the crossed threads. It arrived this past week.

Someone else used that tap by screwing it in from the bottom and out the top of the threads. The tap would go completely through the damaged thread, yet the cone would not start from the top. The damaged threads were still damaged too much for the cone to be screwed in place.
I brought my modified slug there today and screwed it up from the bottom. As it reached the damaged threads, it became stiff. However, unlike the last time I had it in there, I could now make it cut or shove the threads that are crossed. I reached success when the slug screwed its way out the top of the threads. We screwed a new cone in and I tightened it. It’s ready to go as soon as the lower parts that were in our way are screwed back into their respective places.

The original steam cone, by the way, was worn out. Years of hot steam blasting through it has removed a lot of material and has also actually wrapped some of the brass tube that forms the cone inward. That was what was causing the injector to balk and not prime.

Mark D.
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Fitz
Conductor
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Location: Waldport, OR, USA
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Re: Non Lifting Injectors

Postby Fitz » Sat Jul 28, 2018 4:50 pm

Interesting, Mark, and not many people today have the knowledge or machine skills that you have to create tools to do the job and then do it. Good job.
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Mark D
Conductor
Posts: 3145
Joined: Fri Jul 15, 2005 5:01 pm
Location: Sort of between Litchfield and Forest City, MN.

Re: Non Lifting Injectors

Postby Mark D » Sat Jul 28, 2018 5:25 pm

Thanks, Fitz, but actually there are a lot of people with whatever skills I have and far away better than I. I'd place myself a middle of the lineup.
Having the proper tools makes things go better. I was supposed to remove washout plugs but the tool to knock them loose was nowhere to be found. Everyone else had left, so since I couldn't find it anywhere I went home too.
I know I could have used the wrong tool and get it loose, but it would degrade the square pug that sticks out for knocking it loose.

Mark D.
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John Bohon
Conductor
Posts: 370
Joined: Sat Jul 23, 2005 9:30 pm
Location: North Carolina

Re: Non Lifting Injectors

Postby John Bohon » Thu Aug 02, 2018 12:23 pm

Good work Mark. If there is one thing I know about injectors it is that you had better have a good machinist on the property if you want them to work correctly. That and you will spend many hours lapping valves. You are right about nonlifting injectors being the most trouble free but they also are more difficult to regulate water flow to match the engines demands and do not heat the water as much before putting it in the boiler. Everything is a trade off.

John Bohon

Mark D
Conductor
Posts: 3145
Joined: Fri Jul 15, 2005 5:01 pm
Location: Sort of between Litchfield and Forest City, MN.

Re: Non Lifting Injectors

Postby Mark D » Thu Aug 02, 2018 1:32 pm

Correct on all counts. But That's what came with the engine after the Milw. Rd. was done with it. Seems to work well. The one I worked on is 10,000 gal. rated. The other is only 7,000 gal rated. Both work very well, not difficult to prime at all.
Mark D.
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