lifting injector

[andrewsleigh]

Hi all

i have come across injectors than can lift water upwards from the tank.
are they different to normal injectors?

i ask because on my bagnall, i want to have one fed from the saddle, and one from the tender, but where i want to mount them is above the bottom of the tender tank...

its just an idea at the moment, probably wont work..

[h2ogasnz]

Not sure about injectors for models but in the full size world there are two types: non-lifting, mounted bellow the bottom of the water tank level and need a head of water to start and run. 2) lifting injectors, can be mounted above the top of the water level in the tank and will "suck' the water up to them selfs when started.

[peterseager]

The injectors our boiler inspector makes, and we all use, will lift a foot or so. Seen him testing them down the track with the injector fed through a rubber tube from a bottle of water below the injector. The injectors are basically to the LBSC design plus tweaks that he has leant over the years.

Peter

[waggy]

Morning Andrew,

A friend of mine has a freelance tank loco with injectors mounted above the tanks, no problem lifting. They are commercially available number 3 units, bought from Reeves 2000, a company I or he have no connections with whatsoever, apart from being customers.

Good luck,

Waggy.

[ejparrott]

All miniature injectors should lift if built correctly

[jma1009]

hi andrew,

to make a decent lifting injector in miniature very small subtle differences are incorporated in the design of the cones (often by accident!). in designs such as Laurie Lawrence's 'standard' injector published with very detailed notes in ME twice, this design has 'moderate' lifting characteristics and can be fitted above the level of the bottom of the tender. the gordon chiverton injectors (commercial) had 'strong' lifting characteristics, and need extremely good connections to avoid air getting sucked into the water supply.

DAG Brown's designs as per his excellent book are also 'moderate' lifting injectors.

in simple terms the first half of the injector up to and including the gap in the combining cone has to act as an ejector for there to be lifting characteristics. if the first half of the combining cone is too long and the exit via check valve and overflow restricted then the lifting characteristics wont arise. the design of the steam cone also has some effect.

cheers,
julian

[pault]

I remember seeing a Swiss loco that had injectors mounted high up on the backhead but the injectors would not lift the water on start up. This was overcome by a steam turbine centrifugal pump which pumped water at a relatively low pressure into the injector. when the turbine pump was running the injector steam was opened and the injector would pick up. Once the injector picked up the turbine pump was turned off. It sounded like a jet engine spooling up which caused many puzzled looks. The main point was that the injector would not lift the water on start up but once it had hold of the water it would continue to lift it.

[andrewsleigh]

thanks for the replys guys.

so am i right in thinking that any normal injector can lift water?

cheers
Andy

[ejparrott]

It should, I had conversations with DAG earlier this year, assuming of xourse you're not trying to lift it 3'!

[pault]

I think it would be more accurate to say a normal injector may lift water the amount you want when starting

[jma1009]

hi andrew,
dont rely on commercial injectors or those not mentioned by myself above being of the lifting type.
if you fancy making your own, then very happy to help.
cheers,
julian

[Deleted]

For what it's worth, the Isle of Man locos have their injectors on top of the water tanks.

[andrewsleigh]

i dont think i am quite good enough to make my own.

i know a guy who makes some to the chiverton design.

[suctionhose]

Oct 25, 2014 10:00:13 GMT jma1009 said:

DAG Brown's designs as per his excellent book are also 'moderate' lifting injectors.

cheers,
julian

I stand to be corrected but my reading of this book gave me the impression that a chamfer on the second stage of the combining cone was the secret weapon for "lifting"