Boiler check valves

[manofkent]

Hello. I have a 3.1/2" gauge loco. It has 2 check valves (we used to call them clack valves I think?), one for the hand pump and one for the axle pump.
I would like to add an injector - waiting in the station can need a water feed to the boiler. I don't feel up to adding another check valve to the boiler, and wondered if the feeds can be successfully combined into one check valve. I guess I will need more one way valves to protect each combined feed from the other so to speak!
If so, which two feeds would be best to combine. 
Any advice greatly appreciated 
thanks
John

[Lisa]

Hi John,

A fairly simple method of doing this is to connect the hand pump and axle pump in series, then give the injector its own clack. All you'd have to do for this is connect the output of hand pump, to the input of the axle pump.
The hand pump would then pump water through the axle pump and into the boiler, while the axle pump will suck water through the hand pump then feed to the boiler. Note that you'd have to close the bypass to use the hand pump.
The injector then has a clear connection with only one check valve, which will greatly improve reliability.

P.S. Noticed it's your first post here, so welcome!

[Shawki Shlemon]

I have used two supplies through one inlet bush using two clacks in parallel like so .

modeleng.proboards.com/attachment/download/1688

[Jim]

I have a similar system on the Burrell to that described by Lisa and it works just fine John.
Jim

[manofkent]

Thanks all.
Shawki - a very neat solution.
I think the route via the axle pump will be easier for me though - I will have a go at that.

Thanks for your quick responses - a great forum.

John

[jma1009]

I do not like the method suggested by Lisa. The tender handpump (not that I've ever fitted one, as I have an intense dislike of handpumps) imposes a restriction on the flow to the axlepump. The axlepump ought to have it's own delivery, and where boiler bushes are restricted to feed same, Shawki's method is much to be preferred, and was shown in detail also by John Baguley ('Baggo' on here on and off it seems).

I also have an intense dislike of feeding any water into the backhead below the water line. This is the worst place to feed cold water into the boiler as it disrupts the water circulation. The clacks also become temperamental in hard water areas. Water should be fed into the front 1/3rd of the boiler barrel.

What loco is it John?

I commend you for fitting an injector, though hope you get a decent commercial example as they are few and far between at the moment in the UK.

Cheers,
Julian

[steam4ian]

I know it is unusual but why not feed the hand pump through the same clack as the injector?

On my loco the injector and the steam pump both feed through the same clack with a check valve on the injector delivery. They even both work together which surprised me. Became essential last run day because the axle pump failed due to slipping eccentric.

I don't totally like the arrangement because if the steam pump is taken off I have to block off its delivery pipe for the injector to work.

[manofkent]

Thanks for your replies
It is a Bantam Cock loco.
I can see the logic in plumbing the injector both ways suggested. I would rather work with an injector than the axle pump, which is hard to get just right.
Julian, What is your view on Elder Statesman's suggestion of plumbing both injector and hand pump together?
Can anyone recommend a good supplier for an injector?

John

[jma1009]

Hi John,

Bantum Cock is a nice design. It should run well.

Your further query is in fact exactly the solution used by John Baguley and Shawki in effect. 2 seperate clacks are required feeding into a single boiler feed.

Paviersteam supply the Len Steel (Chiverton type) injectors and are the only ones I will recommend commercially, usual disclaimer. Order well in advance.

Cheers,
Julian

[jma1009]

Hi Paul,

Whilst functional, I think you could do better, and the silver solder has melted in the flame resulting in a poor joint.

A standard union nut and cone only needs 4 or 5 threads to be screwed up hard. I counted 15 on one part of your fitting.

When I was a teenager something like that would not have passed Arthur Grimmett's infamous 'window test'!

Cheers,
Julian

[johnthepump]

I well remember Arthur's window test. Arthur's workshop was upstairs and if somebody brought something along and they asked his opinion, if he thought it was not quite up to standard he would suggest the item should undertake the window test. The poor person not knowing what the window test was usual agreed, so out the window the item went much to the surprise of the owner. Can you imagine having run downstairs around the side of the building only to find a very large thicket of brambles below the window. Returning to the workshop some what despondent the person would find Arthur making a start on a replacement part, he would go on to show how to make the part in the correct way. 25 years of Saturday afternoons helping members of the IWMES and others with their model engineering.
John

[GWR 101]

Good- bye

[springcrocus]

Quote:

Hi Paul,

Whilst functional, I think you could do better, and the silver solder has melted in the flame resulting in a poor joint.

A standard union nut and cone only needs 4 or 5 threads to be screwed up hard. I counted 15 on one part of your fitting.

When I was a teenager something like that would not have passed Arthur Grimmett's infamous 'window test'!

Cheers,
Julian

Unquote:

Sept 11, 2016 22:06:45 GMT GWR 101 said:

Good- bye

Well done, Julian, your critism has lead to another member leaving us. You really can be an obnoxious person at times.

Disgusted, Steve

[Jim]

Sept 11, 2016 22:06:45 GMT GWR 101 said:

Good- bye

Hi Paul, That 'Good - bye' sounds ominous I hope you're not leaving the site.

Jim

[runner42]

Hi Shawki,

I am interested in your double clack valve solution but unfortunately for me the black box is obscuring details of the internals of just how the outputs are combined in such a compact manner. Is it possible to provide the drilling details of the black box and are the clack valves ball type that requires gravity to re-seat them therefore the assembly to be mounted vertically?

TIA Brian

[manofkent]

Juliet 2.
I found your picture extremely helpful and I think solves my query.
If I had made it I would be pleased with it - we are not all seasoned engineers after all.
I appreciate your help.
Regards

John

[Shawki Shlemon]

Hi runner42 , it is simply two clacks feeding in the manifold at the top connected to the outlet which is then fitted to the boiler .

[joanlluch]

What is the material for the sealing washers shown the twin inline clacks posted above?. It looks aluminium to me. I would suggest that Aluminium in contact with cooper could create galvanic corrosion which will negatively affect the seal and the look of it.

[jma1009]

I apologise for upsetting Paul (Juliet2) which was not my intention.

My post obviously caused offence for which I apologise. I have not edited it or deleted it as that would be hypocritical.

Cheers,
Julian

[GWR 101]

Julian, thank you for your apology, I would also like to offer my sincere apologies to John who's thread got mixed up in this episode. I hope he has at least found a solution to his original question, best wishes Paul.