Member postings for Jack Lovelock

I much appreciate the injector experiences you have shared which have been very helpful.

I was dismayed to find the bench test on the new No 6 injectors revealed that one had never been completed, with the steam nozzle non-existent. Just a straight drilled 1mm hole! I expressed my frustration with my well-known supplier, which helped to reduce my own embarrassment at not spotting the problem myself.

I am now waiting hopefully for a replacement.

Meanwhile I have ordered D.A.G. Brown's book on miniature injectors.

My interest in electric pumps continues to grow.

Thanks Guys

Regards

Jack

Hi,

I'm a professional engineer, having spent most of my years designing structures and machinery.

My hobby has been the construction of a 71/4" Mikado 2-8-2 loco and tender, which is now almost completed.

Weighing out at 600kg and about 3.4m in length (loco + tender). Draw pull 170lbs or 77Kg.

I also enjoy inventing and have filed about 40 patent applications covering various aspects of engineering.

I enjoy technical challenges.

Regards,

Jack

I am finishing off a 12 year build of a 71/4" 2-8-2 loco and have run into a last- minute frustration with injectors that refuse to work.

My boiler is 50 litres and i have used 3/8" fittings throughout. This includes the copper tubing.

The 2 injectors are 3/8" No8 (160 oz/min) and likewise the clack valves.

One injector sometime works, but the other refuses.

My boiler inspector tells me that the injectors are much too large for the boiler, But there is an arbitrary formular that says the correct injector size should by 4 times the boiler capacity in litres? i.e. 4 x litre capacity = required flow rate in oz/minute. That is for a fast fill. So my No8 injectors should be about right.

However, I changed down to 1/4" No 6 injectors (80 oz/min) which means a change in copper tubing from 3/8" to 1/4". These being placed just a few inches from injectors. Yes, bad practice but where else?

Both injectors refuse to function.

I am currently waiting on a friend to test these injectors on a test rig that he has, but they are unused new injectors and I suspect they will be OK.

I did not appreciate the importance of keeping injector feed and delivery lines free of sharp bends, but now suspect this may be my problem.

I propose changing back to 3/8" tubing and the No8 injectors, but re-pipe eliminating any 90-degree elbows with 30mm radius bends.

I am new to all this and would be grateful for any suggestions or advice.

I'm getting desperate, but not yet to the point of using electric pumps!