The Steamboating Forum

I am contemplating building an injector for Befur with a friend of mine who has successfully made a number of smaller (model engineering size) injectors....

The question is are there designs/specs for Steam Launch size HP (250psi) injectors around???

Thanks

M

Every thought about looking at the nozzel designs for a penberthy high pressure injector and using that as a starting point?

One of my water sources for my launch is a 1/2" high pressure penberthy. It works 50PSI up to 200PSI. I can't tell beyond that because 200 is the MAWP for my boiler.

I could take mine apart and take some measurements of the nozzels/jets and photos if you were interested.

-CB

malcolmd wrote:I am contemplating building an injector for Befur with a friend of mine who has successfully made a number of smaller (model engineering size) injectors....

The question is are there designs/specs for Steam Launch size HP (250psi) injectors around???

Thanks

M

I take it that there are no new ones being manufactured anymore?
There must be build plans for these somewhere.

Hi Malcolm
Did you not stay to hear DAG Brown after the the SBA AGM. I would look first at his book/designs

Mike

Mike Cole wrote:Hi Malcolm
Did you not stay to hear DAG Brown after the the SBA AGM. I would look first at his book/designs

Mike

Sadly Mike, we had to leave because the cold I had given Lou was clearly taking hold! - we do have his book, but the designs are much smaller and aimed at the 100psig range from memory..

Ironman wrote:

malcolmd wrote:I am contemplating building an injector for Befur with a friend of mine who has successfully made a number of smaller (model engineering size) injectors....

The question is are there designs/specs for Steam Launch size HP (250psi) injectors around???

Thanks

M

I take it that there are no new ones being manufactured anymore?
There must be build plans for these somewhere.

Yes you can still buy them, but not at a price I can stomach -

cyberbadger wrote:Every thought about looking at the nozzel designs for a penberthy high pressure injector and using that as a starting point?

One of my water sources for my launch is a 1/2" high pressure penberthy. It works 50PSI up to 200PSI. I can't tell beyond that because 200 is the MAWP for my boiler.

I could take mine apart and take some measurements of the nozzels/jets and photos if you were interested.

-CB

That would be really helpful.... I think we have designs that give basic angles etc., but sizes/bores etc. would be great...

Mal

Pity you had to go because DAG Brown brought along the brazing up jigs he uses for the bodies as well as his cone reamers. His book "Miniature Injectors Inside and Out" (Camden OS, Tee In Stock on website) contains enough to do some sums to calculate nozzle areas for larger examples plus photos of the jigs and details of how to make the reamers. Steam locos used injectors for 275lbs/sqin and perhaps more. More advanced designs allowed steam through put and nozzle positions to be varied but to avoid this two simple injectors, one for high and the other low pressure, can be fitted. They need to have separate suction and delivery pipes and checks. Mine is fairly good coping from 40 to 150 by controlling steam and water supply but the high pressure performance could be more stable, you have to be hands on above 140. Mosquito runs at about 200 and only has injectors, Lake water is quite good quality.

Hi John I have the original Lawrie Lawrence articles on which DAG Brown based his ideas (jig reamers etc). and a good friend of mine has built a number of smaller injectors based on DAG and others work....perhaps a two injector solution as you suggest might be good. I will be condensing so we also need to deal with the hot feed water issue...some experimentation will be needed for sure!

Hi Malcolm,

I'm pretty sure Martyn uses Buffalo injectors on Mosquito and the high pressure one injects just fine at 250psi- not to say he didn't make a set of nozzles to suit an existing body.

Be wary going down the road of buying Penberthy copies- I bought two brand new 1/2" ons off a reasonably well known model engineering company for about a quarter of what I would have paid for the genuine ones. One of them worked perfectly straight off from 70psi up to 150psi, the other one I ended up having to make a 1/4" collar to space the nozzles apart by that amount in order to make it work, and it is still temperamental (they were sold 'tested'!). The company suddenly seemed to stop answering the phone when I tried to take them to task.

Greg