Full sized injector from scratch

[Rwilliams]

Some very incredible work. Injectors are a real puzzle as Jack would tell us. A real challenge to assemble no matter what size, scale or full size. The feeling of going from a pile of parts to a fully assembled and working injector is very rewarding.

Several years ago I was tasked with a pile of parts on a 4X8 sheet of plywood and asked to find three working Nathan Monitor injectors. I soon discovered that even though the parts looked the same and even had the same part numbers stamped in, the thread pitch diameters often did not play well together. It took a while to find enough parts that would play well together in order to make three working injectors. I decided that long ago, each injector must have been a custom build at the factory and parts should not be swapped out without great care. Many times in my quest for three working injectors, I had to make the missing needed parts or to make new parts due to the badly worn condition of the existing parts. Before I was done, I had over 400 hours in the job.

I can see where Anthony has his work cut out for him and will be a far wiser person when the task is completed. I would like to see him making some full size Monitor parts in the future as spares are hard to find these days.

[Taggart]

Incredible! Stunningly beautiful work.

That kind of work would go very well on some theme park trains I'm very familiar with.

[NP317]

Hello My Friends
Absolutely amazing! Those parts belong on a red velvet pillow in a glass case!
Jack

Agreed!
And so much nicer feeding water to a steam locomotive boiler rolling down the rails.
RussN

[AnthonyDuarte]

Still a number of little things to do before I can properly test them, but it’s neat to see it all together!

[AnthonyDuarte]

Two of the #4 injectors are fully assembled and ready to deliver. Had to remake the combing nozzles to get the injector to work to my liking.

I probably won’t be cutting one of these in half any time soon, but for now enjoy this exploded view:

[NP317]

Wow!
RN

[Rwilliams]

What is the gallons per hour capacity of the #4 injector?

Did you delete the check valve on the end of the delivery line to the boiler?

[AnthonyDuarte]

What is the gallons per hour capacity of the #4 injector?

Did you delete the check valve on the end of the delivery line to the boiler?

It's really a 4.3 but I went with Nathan's practice of rounding down since I think a single number looks nicer on the casting.
This puts the capacity at 700 gallons per hour at 200psi, which should be approximately 610gal/hr at 150psi, the customer's operating range.
With "fining down" the injector, the capacity should be a little more than half these numbers. These have 3/4" NPT connections, but the nuts are big enough to accomodate 1" NPT connections.

I axed the delivery check, but there's certainly enough room to put it back in if a customer desires.

For this injector I mostly took from Nathan's overall design. The nozzles, generous overflow, handles, etc. all scream Nathan, but Nathan put that inlet valve inside the water chamber where it can only be maintained by removing the injector, which is ridiculous. That's why they have that "emergency valve" to isolate the inlet valve if it should fail. Then of course the emergency valve can suck in air if it loses its seal. So I borrowed from Seller's way of thinking and moved the inlet valve to a more accessible location and got rid of the emergency valve.

Anthony