injectors

[the artfull-codgerParticipant @theartfull-codger]

laurie lawrence

[the artfull-codgerParticipant @theartfull-codger]

Hi,I was recently discussing injectors with a member of the northern districts model engineering society perth w a [& I was made really welcome as a visitor from uk thanks lads!]& it was mentioned by the chap I was talking to that he had got usefull info from Lauries Notes in model engineer [[Laurie Lawrence]about making injectors,& I wondered if anyone knew which copie[s]numbers of model engineer they were,it would be most appreciated.thanks Graham.

[Clive Brown 1Participant @clivebrown1]

The series ran from ME issue dated 4/04/86 to 17/10/86. 13 parts in all. Recommended

D A G Brown's book "Injectors Inside & Out" (??), is equally useful.

[Clive IndiaParticipant @cliveindia]

Posted by Clive Brown 1 on 22/12/2018 08:52:14:

…..

D A G Brown's book "Injectors Inside & Out" (??), is equally useful.

No matter (I'm not a rivet counter) but it's "Miniature Injectors Inside and Out" – agree, a good read

**LINK**

Edited By Clive India on 22/12/2018 09:36:50

[the artfull-codgerParticipant @theartfull-codger]

Thank you very much for your prompt reply Clive just what I wanted, usefull info I have those issues at home[10,000 miles away] so looking forward to home!! many thanks once again and also to Clive India for taking the time to help me. Kind Regards Graham.

[Martin Johnson 1Participant @martinjohnson1]

Does DAG Browns book address injectors working at up to 160 PSI ? The higher pressures are becoming quite a common requirement on steel boiler traction engines these days. Also, of course quite large rates of feed for 4" and 6" scale models.

Thanks in advance to those in the know.

Martin

[Anonymous]

Posted by Martin Johnson 1 on 08/02/2019 09:45:47:

Does DAG Browns book address injectors working at up to 160 PSI ?

The book is very good on the practicalities and manufacture of injectors, but is weaker on the theory. It doesn't really cover the higher pressures needed for the larger traction engines. That's why I'm going my own way on designing an injector for my 4" engines.

Andrew

[not done it yetParticipant @notdoneityet]

Posted by Andrew Johnston on 08/02/2019 09:53:37:

Posted by Martin Johnson 1 on 08/02/2019 09:45:47:

Does DAG Browns book address injectors working at up to 160 PSI ?

The book is very good on the practicalities and manufacture of injectors, but is weaker on the theory. It doesn't really cover the higher pressures needed for the larger traction engines. That's why I'm going my own way on designing an injector for my 4" engines.

Andrew

Next time I see Derek, in town or at ameeting, I will pass on your comments.

I think he was regarded as too theoretical when he was working, from stories I have heard.

He is the local goto guru, when we have an ‘insurmountable’ problem.

[Martin Johnson 1Participant @martinjohnson1]

Thanks for that tip off, Andrew. I have some other guff in Model Engineers from way back suggesting cone sets for higher pressures, so may kick off with that. I also have a jolly good little squirt, good for 160 psi on the present Burrell (Double B design, now R A Barker) but he wants too many beer tokens for a 6" scale version, so I might measure the existing and scale up.

I am currently reading through a paper on air ejectors and one of the correspondents suggests that not putting in the full length of DeLaval nozzle is beneficial. So it probably is more complex than it looks.

If you want to correspond outwith this forum, I think you already have a p.m.

Martin

[Dave Smith 14Participant @davesmith14]

Martin

If you are interested I spent the last 30 years designing high pressure air ejectors (mainly choked) in aerospace. PM me if you want to swap info.

Regards

Dave

[Anonymous]

Posted by not done it yet on 08/02/2019 10:49:14

Next time I see Derek, in town or at ameeting, I will pass on your comments.

Fine by me, I'll be interested in the reply.

There is also a book by Ted Crawford, 'The Model Injector' which goes into the theory more mathematically, albeit with a lot of fitted formulae rather than fundamental physical principles. The practical side of the book covers much the same material, but in a less detailed manner with fewer actual designs.

I've also bought a couple of books aimed at professional engineers. Given they where published in the early 20th century the units are rather odd (to me) but they go into a lot of detail on the theory. In one book they show that the maximum temperature of the feed water varies with boiler pressure, as it must. And it is not constant, as was expounded some while ago in a thread I started on injectors. It is also interesting that many of sectional drawings of full size injectors do not have an expanding part of the steam cone after the throat even though nearly all model injectors do.

Andrew

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