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Post by charley on Jun 3, 2012 11:49:17 GMT
I've read a lot on the forum about published designs. I'm currently stripping a part built 2.5 inch Bassett Lowke Flying Scotsman. It never had a boiler constructed. The drawings I have date from 1954.
The drawings show the axle pump and hand pump feed entering the backhead through a shared check valve. Is this design still valid?
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Post by Shawki Shlemon on Jun 4, 2012 10:44:03 GMT
I am not sure what the rules in UK are but here in OZ you must have two separate and independent systems ( I think in UK is the same ) . You can put two supplies through one clack provided each supply have its own inline clack ( this will be counted as one supply ). That is what I would be doing , you may get other opinions .
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Post by lennard1200 on Jun 4, 2012 23:55:01 GMT
You are dead right Shawki. The new boiler regs on this dont appear to have changed, but I'm not sure if your comment that two supplies using a common clack are considered as one supply is correct. [ given they both have their own clacks ] May be the way that I'm reading it though.
cheers,
leonard
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waggy
Statesman
Posts: 744
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Post by waggy on Jun 5, 2012 7:50:40 GMT
Morning Charley,
The best advice here is to discuss your boiler feed(s) with a boiler inspector.
Waggy.
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Post by Shawki Shlemon on Jun 5, 2012 10:18:51 GMT
Leonard , Here in OZ the two systems must be independent of each other , I am a boiler inspector and I would not accept that arrangement as two supplies .If the main clack fails ( get stuck ) there will be no water , there is no second alternative supply .
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Post by lennard1200 on Jun 7, 2012 0:30:46 GMT
Thanks Shawki, thats sorted my thinking out. Two supplies with their own clacks into a common bioler feed is OK ? Correct.?
cheers,
Leonard
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Post by Boadicea on Jun 7, 2012 8:15:52 GMT
"Boiler feed arrangements by at least two independent means" is the statement in the UK Boiler Code 2008 (latest edition).
Leonard, I think you are suggesting using one pipe. I think then you are in the realms of interpretation. People could argue forever whether one pipe, however short (even a tee), meets the criteria, as they have done on this forum many times before.
Since charley is making a new boiler I think he should play safe and use two separate input flanges on the boiler.
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Post by Shawki Shlemon on Jun 7, 2012 9:41:03 GMT
May be I did not explained clearly , in my opinion , to have two independent supplies one must have two boiler clacks , that is what I meant , in the second statement I said that you can have two supplies into one boiler clack provided they have their own inline clacks but it will be considered one supply , to give an example an axle pump and a hand pump going to clack no 1 and an injector going to clack no 2 . I must have messed up in the way I wrote the last reply , my apology .
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pault
Elder Statesman
Posts: 1,497
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Post by pault on Jun 7, 2012 11:44:52 GMT
Hi All
This debate over 2 independent means of feeding the boiler always makes me smile. In this thread we are saying that it is debateable if two feed devices feeding through one pipe can be classed as independent. How many tender locos have their tender tanks partitioned so that in effect they have two tanks? Surely having two feed devices which draw water from a common source (tank) cannot be considered to be totally independent systems. When one tank is empty both systems fail to deliver. IMHO if you are driving a loco you must be able to deal with failures, having two totally independent feeds is not a 100% guarantee you can feed water into the boiler. Remember a few years ago when the full size Duchess of wherever had both injectors fail when the tender was topped up with hot water by a tanker driver who thought it would be helpful to use hot water.
Regards
Paul
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Post by GeorgeRay on Jun 7, 2012 18:59:51 GMT
One thing that needs to be considered is that the Bluebook contains the following statement. 'On boilers of less than 10 bar litres with a boiler capacity of less than 2 litres it is acknowledged that the provision of two independent means of water feed arrangement may not be possible. Therefore for the purpose of testing these boilers one means of water feed is acceptable.' Surprisingly my 5" gauge Terrier falls into this category.  |
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Post by charley on Jun 7, 2012 21:34:40 GMT
Sorry if i dredged up an old chestnut that has been discussed before but I'd like to thank you all for the advice.
I'll consult the boiler inspector at my local club and see how to proceed.
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Post by Boadicea on Jun 8, 2012 7:46:27 GMT
One thing that needs to be considered is that the Bluebook contains the following statement. 'On boilers of less than 10 bar litres with a boiler capacity of less than 2 litres it is acknowledged that the provision of two independent means of water feed arrangement may not be possible. Therefore for the purpose of testing these boilers one means of water feed is acceptable.' Surprisingly my 5" gauge Terrier falls into this category. Good point Jack - missed that. |
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Post by lennard1200 on Jun 9, 2012 0:12:35 GMT
No apology required Shawki. After reading it a few times all became plain. its a bugger when the grey cells get old.
cheers,
Leonard
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Post by charley on Jun 17, 2012 18:40:28 GMT
Thanks for all your answers.
I calculated the size of the boiler plus five water tubes is approximately 1.35 litres.
The pressure is 80- psi which is roughly 5.52 bar
So the bar litres should be approx 7.5.
I haven't seen the club boiler inspector but hopefully when the club is open on a monday or a tuesday I'll ask his opinion about the original design.
Cheers
Charley
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