Post by steam4ian on Jun 24, 2020 8:25:01 GMT
There is a thread running at present regarding coal with comments about the smokiness of Columbian coal.
Here in Aus we were spoiled for a number of years by the availability of Char, this was pyrolised coal prepared as a smokeless fuel for institutional boiler and heating systems. It was an excellent miniature loco fuel. Unfortunately it is no longer available and we have had to resort to using "real" coal. whilst Australia exports immense quantities of the stuff, finding anybody who will sell you less than a train load is problematic. As miniature operators we have had to pal up with preserved full size operations to be able to raid their coal stocks.
As coal this fuel is great except for the smoke. We are finding too many passengers no longer like the coal smoke atmosphere and avoid riding behind steam locos.
So much for the preamble.
Smoke was also a nuisance in full sized practice when boilers were being forced. In the USA they came up with a steam/air jet system which blasted into the firebox. By directing the jet through firedoor directly at the brick arch the flame path could be folded back on itself thus allowing a longer combustion time. This system was applied with great effect on the 520 class locos of the SAR (Australia); it was only removed when they were converted to burn oil and coal together during coal strikes.
The point
Miniature locos do not have a brick arch and it is my experience that the short flame path leads to smoke generation.
To lengthen the flame path I am suggesting two steam jets in the firebox. These would be located at the very front of the grate and aimed back over the fire so the flame is directed back towards the back of fire box.
Before I invest more time and thought into this proposal I would appreciate the thoughts of others.
Regards
Ian
Here in Aus we were spoiled for a number of years by the availability of Char, this was pyrolised coal prepared as a smokeless fuel for institutional boiler and heating systems. It was an excellent miniature loco fuel. Unfortunately it is no longer available and we have had to resort to using "real" coal. whilst Australia exports immense quantities of the stuff, finding anybody who will sell you less than a train load is problematic. As miniature operators we have had to pal up with preserved full size operations to be able to raid their coal stocks.
As coal this fuel is great except for the smoke. We are finding too many passengers no longer like the coal smoke atmosphere and avoid riding behind steam locos.
So much for the preamble.
Smoke was also a nuisance in full sized practice when boilers were being forced. In the USA they came up with a steam/air jet system which blasted into the firebox. By directing the jet through firedoor directly at the brick arch the flame path could be folded back on itself thus allowing a longer combustion time. This system was applied with great effect on the 520 class locos of the SAR (Australia); it was only removed when they were converted to burn oil and coal together during coal strikes.
The point
Miniature locos do not have a brick arch and it is my experience that the short flame path leads to smoke generation.
To lengthen the flame path I am suggesting two steam jets in the firebox. These would be located at the very front of the grate and aimed back over the fire so the flame is directed back towards the back of fire box.
Before I invest more time and thought into this proposal I would appreciate the thoughts of others.
Regards
Ian