Water glass blowdown
Water glass blowdown
What is the proper procedure for blowing down.a locomotive water glass ?...I see it done, different ways?
Re: Water glass blowdown
Assuming the valves are plumbed correctly,
1. Close the upper (steam) and lower (water, hopefully) shutoff valves.
2. Slowly open the drain valve. If water comes out, the lower shutoff valve is leaking. If steam, the upper valve is leaking.
3. Slowly open the lower valve and let water run through the drain for 5 seconds or so, then close the lower valve.
4. Slowly open the upper valve and let steam run through the drain for 5 seconds or so, then close the upper valve.
5. Close the drain valve
6. Open the lower valve
7. Open the upper valve
8. After several seconds you'll see the glass stabilize at the boiler water level. If in doubt, verify with the try cocks.
At least that's the way I do it, with the proviso I'm not a licensed steam operating engineer. The theory of course is to demonstrate a clear path from the boiler through both shutoff valves to the drain valve.
1. Close the upper (steam) and lower (water, hopefully) shutoff valves.
2. Slowly open the drain valve. If water comes out, the lower shutoff valve is leaking. If steam, the upper valve is leaking.
3. Slowly open the lower valve and let water run through the drain for 5 seconds or so, then close the lower valve.
4. Slowly open the upper valve and let steam run through the drain for 5 seconds or so, then close the upper valve.
5. Close the drain valve
6. Open the lower valve
7. Open the upper valve
8. After several seconds you'll see the glass stabilize at the boiler water level. If in doubt, verify with the try cocks.
At least that's the way I do it, with the proviso I'm not a licensed steam operating engineer. The theory of course is to demonstrate a clear path from the boiler through both shutoff valves to the drain valve.
John Brock
Re: Water glass blowdown
jcbrock's water glass check method corresponds with the method we used and taught at both the NW Railway Museum and the Mt. Rainier Scenic Rwy.
Good double checks are built in, and I still practice that on my steam locomotives.
RussN
Good double checks are built in, and I still practice that on my steam locomotives.
RussN
Re: Water glass blowdown
I was taught to do a LU LU by the late road foreman from the Ca. State RR museum. A LU LU, is to close the lower glass valve and open the drain, close the drain, open the lower valve. Then close the upper and open the drain, close the drain valve and open the upper valve. Repeat the procedure a second time. Hence it being named LU LU ( Lower, Upper, Lower Upper).
Re: Water glass blowdown
And remember that FRA rules call for (or at least used to) annual removal from the boiler and cleaning of the water glass valves.
Twenty fives years ago the crown sheet failure on the ex-Canadian 4-6-2 on the East Coast of the USA was in part attributed to those water glass valves being partially plugged, due to lack of scheduled maintenance.
RussN
Twenty fives years ago the crown sheet failure on the ex-Canadian 4-6-2 on the East Coast of the USA was in part attributed to those water glass valves being partially plugged, due to lack of scheduled maintenance.
RussN
Re: Water glass blowdown
How jcbrock describes the procedure, is how I do mine....I have seen live steamers, simply open the bottom waterglass drain and blow it down ?....in the winter off season, I remove my water glasses, this is easy, since I use unions for all my connections...and make sure there is no obstruction in the glass, or in the top and bottom valves and associated piping