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Speedy Builder508/05/2022 17:54:09
2613 forum posts
212 photos

What is the meaning of a No 2. 11 oz/ minute Injector. Does it have a capability of injecting 11 Oz weight of water or 11 Fluid Oz of water.

11 Oz = .372 Fl Oz = 0.186 UK pints

11 Fl Oz = 0.55 UK pints.

SillyOldDuffer08/05/2022 18:21:01
8691 forum posts
1967 photos

Don't panic! I think saying 11oz = 0.372 floz is a mistook. For all practical purposes, I believe a fluid ounce of water weighs about an ounce, so the injector is good for 11oz weight and 11floz volume in one minute.

Strange that Imperial fan-boys are nowhere to be seen when questions like this pop up. Do they think imperial is wonderful because the tiny bit of it they know is familiar, not realising the full system is horribly complicated? Ignorance is bliss!



JasonB08/05/2022 18:31:34
22749 forum posts
2653 photos
1 articles

As Dave says you 0.372 is way off

1oz weight is approx 1.04 fl oz assuming it's water we are talking about



Edited By JasonB on 08/05/2022 18:34:19

Andrew Johnston08/05/2022 18:31:40
6601 forum posts
701 photos
Posted by SillyOldDuffer on 08/05/2022 18:21:01:
Strange that Imperial fan-boys are nowhere to be seen...

May be they're waitng for **** to rush in where angels fear to tread? teeth 2


Speedy Builder508/05/2022 21:12:10
2613 forum posts
212 photos

Thanks for that gentlemen. I was trying to equate LBSCs injector for my SPEEDY loco where he estimated that his would inject about a pint in in 2.5 mins .

So with a No 2. 11 oz / min injector = 0.55 pint / min is approx 1.4 pints in 2.5 mins.

That should do nicely.

norm norton10/05/2022 14:47:59
186 forum posts
9 photos

The nominal sizes and flow rates are only an estimate to performance.

If it is of any help, I would suggest that you could easily use No3 or 16oz injectors on a 5" tank loco. The larger sizes tend to work more successfully than the smaller, and a No3 might fill half a glass in 10-20 seconds?

Speedy Builder510/05/2022 16:14:45
2613 forum posts
212 photos

Thanks Norm, Its a confusing subject when tubes may be specified as bore or overall diameter. I already have the #2 injector , so will persevere with that. I am making a new check valve with a 7/32 ball as specified by Macc models and 5/32 od steam feed pipe and 3/16 od delivery pipe. At same time making sure the cold flow is adequate by making a temporary cold from an auxiliary reservoir.

Once I can get it working, can refine the system.


norm norton10/05/2022 19:22:50
186 forum posts
9 photos

Sounds good Bob. You will have more than adequate pipe sizes as I use only 1/32" larger for No4 24oz injectors. You should find that you will only need a weak dribble of free flowing water before you turn the steam on as the injector will suck like mad and get all the water it wants. The thing to watch is any trace of air leak in that water feed because the suction will pull in any air and then the injector will misbehave.

Speedy Builder527/05/2022 18:30:57
2613 forum posts
212 photos

Update, 5/32 steam feed pipe, 3/16 OD delivery and cold feed via tin can / 3/16 pipe with cold water. The new check valve with a 5.5mm (7/32) ball still dribbles, so it was back to the check valve with the 3/16 ball (changed from stainless to a Viton ball)

The number 2 injector works fine approx 1/2 pint of cold water in a minute with steam feed at 60 psi.

The next trial will be using warm 60 deg C water - the side tanks on SPEEDY warm up in spite of 2 layers of insulation between tank and boiler.

After that it will be "plumbed in" to the side tanks again.

Has anyone got experience of getting injectors to work with "hot" water ?


Paul Lousick28/05/2022 01:03:05
2043 forum posts
722 photos
Posted by Speedy Builder5 on 10/05/2022 16:14:45:

"Its a confusing subject when tubes may be specified as bore or overall diameter. "

Tube and Pipe are not the same. Tube normally has thinner walls and specified by its OD. Pipe is bigger and heavier and specified by its nominal bore size and a schedule/wall thickness. (refer to British Standard Pipe tables for the actual pipe OD)

Pipe is specified by a nominal (average) bore size because the actual inside diameter varies, depending on the thickness of the wall. The OD has to be a standard diameter to mate with attached fittings. (elbows, tees, etc).

(Bore size for piping was used because it is an easier unit for calculating the volume of liquid contained in the pipe)

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