Injector Overflow Pipe

[smallbrother]

Advice needed please.

1. What is the usual way of connecting a copper pipe extension to the injector overflow? I cannot see the injector and would like to fit an extension pipe to somewhere I can see the outlet on the run.

2. The drain cocks have very thin pipes but some have been lost. How are these best fitted?

Thanks guys,

Pete.

[ejparrott]

1. Usually just screws into the bottom of the body

[smallbrother]

Jun 2, 2015 20:41:52 GMT ejparrott said:

1. Usually just screws into the bottom of the body

I guess I need to make a thread in the injector overflow and on the end of the pipe?

[peterseager]

Our Secretary makes the injectors I use and he puts a standard nut and olive connection with a short length of pipe on the overflow. Very useful if you want to modify it.

Peter

[donashton]

Injector overflows should be as unrestricted as possible, otherwise you could find that what works at present will not even start after fitting a pipe.

Don.

[ejparrott]

Jun 2, 2015 21:33:38 GMT smallbrother said:

Jun 2, 2015 20:41:52 GMT ejparrott said:

1. Usually just screws into the bottom of the body

I guess I need to make a thread in the injector overflow and on the end of the pipe?

Does it not already have one?? All of mine (apart from the home made Hunslet) have threads in the overflow outlet for exactly this purpose, some are supplied with a very short length of pipe already in.

I'm just about to do the same to the club's Scot for the same reason, they're tapped 1/4" x 40

[Cro]

On one of my 9f injectors it is hidden so I just bent a piece of pipe the required length and shape and using a suitable bit of rubber pipe 'joined' the two together. That way I can easily remove the extension of i change the injector over. Doesn't effect the performance of it in any way.

[61962]

Pete,

cro has got it right. I've extended injector overflows this way for almost forty years. Just make sure the extension lines up with the injector overflow pipe and is fixed to the loco frame or footstep so it can't move and kink the flexible connection. The longest overflow I have is about 3 inches long and is 3/16" OD copper, this on an 11 ounce injector which works perfectly. Bigger injectors will need bigger overflows. One thing, please remember to turn the overflow so it discharges almost parallel to the track so you won't squirt bystanders with hot water or steam.

Eddie

[fostergp6nhp]

How about making the extension fixed on the loco out of a tube size that the original as supplied overflow pipe will slip into, then there is no messing with changing the pipe or fiddly bits of rubber etc.

[jma1009]

i have been somewhat hesitant to join in this debate re pete's request for advice. this is partly because many commercial injectors can be an unknown quantity and some are a lot better than others - and therefore more forgiving of alterations that may cause problems.

generally (and this was something drummed into me when i started this lark) a restricted overflow pipe either of long length or with internal restrictions can cause problems. i agree with Don Ashton. most commercial injectors are supplied with overflow pipes of short length and tested with them fitted. Ted Linden (on one of his very few public statements) down to John Cashmore have all stated that a long overflow can cause problems.

a far better solution is to arrange the injector pipework so that the injector is conveniantly positioned for removal and with a short overflow without restriction. or bend the water supply pipe so the injector is at a slight outward angle re the overflow. the injector doesnt have to be 'upright'.

Eddie has a different arrangement but i would expect his to work given his excellent workmanship and attention to detail and operation. others may misinterpret and arrive at problematic arrangements.

for myself i never look at the injectors when operated. if i hear a rush of steam i know they arent working (because the tender is empty!). the overflow pipes do bend slightly outwards and some are longer than others, so if i bothered to look i could see them.

i am currently sorting out two commercial injectors for a friend in hampshire for a very fine loco where the top operating range is restricted, but where long overflows have been added. i have told my friend my views on his long overflows!

if you must have a long overflow pipe then add a hole in the pipe close to the injector body. and under no circumstances must there be any restriction in the pipework.

pete, if you want some new pipes making please let me know and i will be happy to help.

cheers,
julian

[smallbrother]

Interesting thoughts there Julian.

The injector appears to be home made and has some unusual sized threads on the steam and boiler feed connectors.

I have been gradually eliminating problems with the water supply and the injector works more often than not. However, the injector splutters at the best of times and without visual assurance I would not want to assume it was operating. Strangely, even with the splutter, it feeds water very rapidly.

I am due to run at Cardiff's rally today so will see how we go and I will get back to you.

Thanks to all,

Pete

[Tony K]

Jun 4, 2015 21:58:05 GMT jma1009 said:

....for myself i never look at the injectors when operated. if i hear a rush of steam i know they arent working (because the tender is empty!).....
cheers, julian

brother, Julian has the real answer - spend your time getting the injector(s) to work properly - then you will not need to look at the overflow.

[ejparrott]

Sorry, disagree. Get them to work yes, but a visible overflow is a must, otherwise, why would the LMS, LNER, GWR, SR, BR etc have bothered spending the money on the (usuallly) copper pipes to bring them to a visible point.

[smallbrother]

It is amazing what a good discussion can do to focus the mind.

I had a fabulous run at the Cardiff Rally today, and as a result of this thread, I tried just a bit harder to view the overflow and low, it doesn't mean I tip off or strain my back.

So, next task is to sort out a bigger water tank for my trolley. I think the pipework can also be improved but between the injector and axle pump I have a very decent loco to run whilst I make these improvements.

Once again many thanks to all.

Pete.

[fostergp6nhp]

Ed on a full size engine you will probably not be able to hear the injector so being able to see the overflow is a must.

[jma1009]

hi ed,
i would agree with fostergp6nhp, plus fullsize injectors have to work over a much bigger range than in miniature and many fullsize injectors are not properly maintained and are worn. there is a whole website devoted to the injectors fitted to FR 'double fairlee' Merddin Emrys which are the original injectors that are very problematic! i can think of lots of similar examples in fullsize where the injectors dont work half as well as those we use in miniature!
cheers,
julian

[ejparrott]

Maybe on big mainline stuff, but you can hear them perfectly well on TR engines and 2' stuff

[mbrown]

.... didn't stop me leaving the injector on No.3 "Sir Haydn" once in my firing days when coasting back from Abergynolwyn. The driver and I got into a conversation and the first we realised was when he opened the regulator and got a shower from the chimney.

But, seriously, I thought that in "our" sizes, a good injector that isn't pulling air in through the overflow ought to be silent. My Chiverton injectors on "Darent" and "Lyn" are silent in operation. The only way I know whether they are on or off is by the position of the controls.

Malcolm

[rogsteam1959]

Where is the best place to buy an injector.
I would like to have one as a spare part.
Thank you
Michael

[ejparrott]

Sadly the days of buying top quality miniature injectors seem to have passed, or at least there is a current lack of supply. I have however been hearing good reports of those purchased from Polly/Bruce Engineering, though I haven't bought any myself to give you a personal answer. I suspect I will be able to in due course as it appears the one for the 2.5" has gone AWOL!