In continuation of the same locomotive (see reflex water gauge thread), it is also fitted with a continuous blow down system. I believe it to be a version from Barco (Nalco) as the Swedes have bought and adopted many other American appliances on their locomotives.

The system has worked before, but something never functioned quite right and now it apparently doesnt work at all. Being that we're doing major work after eight years of storage, I'd like to give it a good look through and see if I cant make it work before the others proceed to blank the flange off and remove the system. The surviving sister locomotive in Sweden had the system removed upon entry into preservation, so the group unfortunately cant help us.

What I am interested in are detailed drawings of the valve unit that actually admits the water from the low point on the boiler up till the "pot" so to speak.

Any help is greatly appreciated!

Be aware that there are two places a continuous blowdown system needs to draw from. Sludge is removed from the bottom of the boiler, and foaming concentration from close to the effective steam/water interface. (In water tube boilers this is tapped off all along the drum, but that's probably not cost-effective for a variety of reasons on a firetube locomotive boiler).

The 'catch' is that the minimum flow of a bottom system has to be sufficient -- or the valve needs to be periodically adjusted -- so that the minimum amount of continuous-blowdown mass flow to eliminate the TDS buildup is sent through the system BUT the valve and line don't clog with sludge or its baked-on evaporated constituents. If you're having trouble with the system, look to the port size of this valve, and the chemical constituents of your water, TDS and sludge, etc. Note that modern continuous-blowdown valves often have specially hardened and configured seats and at least some of them have power operators.

The 'pot' is likely a flash tank, where as much of the tapped boiler water as possible is permitted to 'flash' to clean steam, concentrating what has to be dumped overboard to a minimum (a very corrosive minimum, but I'll come back to that). Some systems can be arranged to recapture both the flashed steam and some of the heat from the concentrated water, but as with many methods of 'thermodynamic optimization' that work on large stationary power systems the actual return (even the operational benefits) may not be worth the investment in capital and maintenance. So you may have something that only vents the flashed steam from the top of the 'pot' and the separated water from the bottom, and both of those valves will have to be carefully set relative to the primary blowdown valve under the shell.

Personally I don't see how you can set a system like this without removing it, checking and cleaning all the valves, and doing some careful calculation on how much water you want or need to pass through the thing. (And of course decide how much and what kinds of TDS you want to be blowing down, vs. retaining in your boiler chemistry...)

Placement of the blowdown drain is more of an issue now than it was in the bad old days. Centering it leaves a dribble trail of highly caustic sludge and hot water down the center of the track, together with any switchpoints or bars happen to pass beneath. Leaving it near a rail spatters the railhead with slimy and corrosive stuff. Leaving it outbound is a burn hazard waiting to pounce. I'd be interested in having the operators here describe how they practice both periodic and continuous blowdown in their particular operating environments.

I dont know if this helps, but this is the arrangement that currently exists. Perhaps the casting number on the regulating valve is a good giveaway? I cannot say what is supposed to connect to the three small threaded connections radiating from the vertical cylinder body. Something to a regulating valve? The large threaded connection is the feed up to the flash tank on top of the cab. The pipe leading away from the valve is to a valve outside the cab for drainage purposes. There is no secondary connection to the boiler Overmod mentions unless it is supposed to come from one of the smaller thread connections.

edit:
The lower of three threaded connections could be a connection for a vent?
The upper two could be connection to steam from the locomotive, with one being used and the other as a second connection point option?

I have been informed I may have a Nalco continuous blow down system on my hands instead of Barco. I have found a rough drawing of the system and agree this is probably what I have. I will change the title to reflect the recent finding.

With this in mind, I hope that someone might have some drawings for the nalco system in their posession

Stuart,

Based on my experiences with CNR steam locomotives, here is what I know about NALCO Continuous Blowdown:

There seems to have been two configurations of it, both which which seems to have utilized the same parts. The earlier (circa earl mid 1940s) usage seems to have been the application of this device at the mudring, while virtually all installations of this device were on top of the boiler, where it just drew water from the top (or thereabouts)of the water line. I get the feeling that the boiler top installation may have superseded the mudring installation (at least on the CNR)

The operation was pretty straight forward as in both cases it is activated by a sensing line that is connected to one of the steam pipes to the cylinders so that it only activates when the engine is moving.

I think the goal of the top mounted installation was more along the lines of reducing the TDS level of the water. Note that even with this device installed, engineers were still required to open the manual blowoff cocks to reduce sludge.

I have for you the following:
-A NALCO Diagram showing the mudring installation of this system
-Details photos of the boiler top installation on CNR 6167
-Photos of the steam seperator and related piping
-The instruction sign installed in the cab of engines so equipped with a NALCO Continuous Blowdown.

Details on the installation on CNR 6167.

If memory serves me correctly, I believe the vent pipe just connects into the discharge line.

Details of the steam separator piping. The discharge line runs under the boiler jacket to the cab, where it runs through the ceiling to the back corner of the cab where it exits out to the separator, and the condensate drain then returns to the cab and runs down the back corner of the cab and drains at track level.

Here's an example of the sign in the cab. I'm assuming these were made by CN. There was another version of the sign for engines only equipped with manual blowoff cocks. I haven't been able to determine if there was a version for engines equipped with the Signal Foam Meter.

And for kicks, here's the patent!

EDIT: Found the patent for the steam separator as well.

QUESTION: While the patent numbers were taken from the Nalco drawing, the Patent for the CBD system is credited to a Mr. Verl E. McCoy of Wilson Engineering, while the separator is credited to a Mr. Lyndon F. Wilson.

I'm told that Wilson Engineering did in fact produce a feed water heater system (that was at least used on one CNR 2-8-0, #2758), does anyone know if and what the relationship of Wilson Engineering to Nalco was, or perhaps it was as simple as McCoy and Wilson defected to NALCO etc.