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injesctor's
https://www.rypn.org/forums/viewtopic.php?f=1&t=4828		 Page 1 of 1
Author:  Pat Fahey [ Thu Jan 16, 2003 8:16 pm ]
Post subject:  injesctor's
What is the most realible type non-lifting or lifting type,,,and what is the most eastest to service,,,,or are they about the same,....thank you Pat

cprh1b@attbi.com
Author:  dave [ Thu Jan 16, 2003 8:50 pm ]
Post subject:  Re: injesctor's
> What is the most realible type non-lifting
> or lifting type,,,and what is the most
> eastest to service,,,,or are they about the
> same,....thank you Pat

All are tempermantal and work on black magic, but nonlifters don't need a perfectly tight feed line from the tank. The feed by gravity not vacuum. One less potential problem to ruin your day.

dave

irondave@bellsouth.net
Author:  Jack Anderson [ Thu Jan 16, 2003 10:45 pm ]
Post subject:  Re: injesctor's
>We don't have any non-lifters on our 8 engines. As for lifting injectors there is nothing as sweet and easy to maintain than the Sellers brand.

steamrr@mashell.com
Author:  Roger Mitchell [ Thu Jan 16, 2003 10:57 pm ]
Post subject:  Re: injesctor's
> All are tempermantal and work on black
> magic, ^^^^^^^^^^^^^
I agree that non-lifting is more reliable than lifting, but if properly maintained, injectors can be reliable. The big difference is that if the injector gets too hot due to a leaky steam valve, on a non lifting injector all you have to do is turn on the water supply valve and let some run out the over flow to cool it off. You do not have that capability with a lifting injector. If they do get tempermantal, there is usually a reason for it. Obstructions in the lines or cones of the injector or lime buildup in the cones can be disasterous to the operation of an injector. As to what makes an injector work, it is the difference in temperature between the steam and the feed water. The steam travels through a narrowing cone to increase it's velocity using the venturi principle. It then enters the combining cone where it condenses rapidly into the water from the tender tank imparting it's velocity into the water. The water then enters a widening cone where it's velocity is converted into pressure, enough to overcome the pressure of steam in the boiler. A french man named Henri Giffard invented it in an attemp to do away with the weight of heavy steam driven feedwater pumps for a steam powered derigable. Needless to say he did not do away with the heavy weight of boilers, steam engines or water and it flew like a lead balloon even though he did fly it.
Roger Mitchell
Master Mechanic
Fort Collins Municipal Railway


Fort Collins Municipal Railway home page
n0mcr@netzero.net
Author:  Tom Shreve [ Thu Jan 16, 2003 11:27 pm ]
Post subject:  Re: injesctor's
What is the best injector? The one you have the most spare parts for.

ironbartom@aol.com
Author:  Tim S [ Fri Jan 17, 2003 12:02 am ]
Post subject:  Re: injesctor's
I have to agree about the Sellers Lifting Injectors. We have two of them on our #12. One class M and a class NS improved. They work very well and rarely give trouble.

Tim

tssmith@boone.net
Author:  dave [ Fri Jan 17, 2003 8:12 am ]
Post subject:  Re: injectors and parts
> What is the best injector? The one you have
> the most spare parts for.

Sources are making parts for Nathan (Backshop) and Sellers (Strasburg) and some midwestern traction engine source is making Penberthy components if you really want to go there.

Having worked on a bunch of different kinds, I like the lifting Hancocks least and Sellers best. Hancocks physically shut off the overflow when you start them after priming, so if they break there is no obvious sign. This can make things exciting for a green fireman.

Nathan style guns have a seperate priming valve which is easy to learn to use, while some finese is required to prime Sellers with the steam ram cracked open just right.

Dave

irondave@bellsouth.net
Author:  G. Mark Ray - TVRM [ Fri Jan 17, 2003 9:58 am ]
Post subject:  Re: injesctor's
The most aggravating problem we've had with the non-lifters is not the injector but the starter valve. We have finally trashed the nathans and are now using 2" stainless steel quarter turn ball valves with a redesigned linkage. Since the rate at which the valve is closed is dependent upon the operator, the resultant water hammer in the delivery pipe is somewhat reduced and this results in less banging of the check valves.

As far as to which is best... Give me a Nathan 4000 or give me death.

TVRM Shop Updates by Steve Freer
aw90h@cs.com
Author:  J.David [ Fri Jan 17, 2003 3:09 pm ]
Post subject:  Re: injectors and parts
> Valley Railroad at Essex, Connecticut makes nozzels for Nathan Simplex Type R Number 9 lifting injectors. J. David (860-767-2021)

jdconrad@snet.net
Author:  M Austin [ Fri Jan 17, 2003 4:43 pm ]
Post subject:  Many injector problems...
...aren't caused by the injector.
Many locos have had the factory stop valves and check valves replaced with globe valves and lift checks instead of gate valves and swing checks. (Because of maintenace issues, they are easier to lap.)
Fluid flow through a lift check or globe valve has to make two hard right turns and then some PLUS a choked flow area. From the Lunkenheimer Equivalent Resistance Table, additional resistance from a gate valve is the same as 1.35 feet of extra 2" pipe. Whereas, the globe valve offers the resistance of 61.5 extra feet of pipe between the injector and the boiler. A globe valve AND a lift check boosts the resistance up to 123 extra feet of 2" pipe.
It is amazing how UNfinicky an injector gets without the extra resistance.
Author:  dave [ Fri Jan 17, 2003 6:14 pm ]
Post subject:  Re: Many injector problems...
Amen Matt - and all parts you need can be ordered from off the shelf sources like McMaster. One of my favorite retrofits.

Dave
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