Re: Coal fired Garratt K1
Posted: Wed Mar 03, 2021 8:25 pm
I have just about finished the pump.
I have soft soldered the two new valve faces into position, using PTFE tape inserted into the steam drillings to try to prevent them filling with solder. It worked. In fact I pre-soldered each face carefully and held them together while I just melted the solder. I think the technical term is "sweating".
I have made a few more new components - particularly the tube which connects steam unit to the actual pump. It has a slot in a different place, and the rocking arm which moves the valve. I had to make that a few times to get the motion right.
So here is a short video of the pump running (dry) on air at 12psi:
https://www.dropbox.com/s/5qr4xtcic7cwd ... 1.m4v?dl=0
I might make a better rocking arm - the one in the video obviously does the job but it could be improved. I am after reliability! By the way the pump starts whenever the air valve is opened - no hesitation and it doesn't mater what point in the cycle it had stopped at. So I am happy.
A few final adjustments and it can go back onto the loco. Then on to clack valve and piping.
I have soft soldered the two new valve faces into position, using PTFE tape inserted into the steam drillings to try to prevent them filling with solder. It worked. In fact I pre-soldered each face carefully and held them together while I just melted the solder. I think the technical term is "sweating".
I have made a few more new components - particularly the tube which connects steam unit to the actual pump. It has a slot in a different place, and the rocking arm which moves the valve. I had to make that a few times to get the motion right.
So here is a short video of the pump running (dry) on air at 12psi:
https://www.dropbox.com/s/5qr4xtcic7cwd ... 1.m4v?dl=0
I might make a better rocking arm - the one in the video obviously does the job but it could be improved. I am after reliability! By the way the pump starts whenever the air valve is opened - no hesitation and it doesn't mater what point in the cycle it had stopped at. So I am happy.
A few final adjustments and it can go back onto the loco. Then on to clack valve and piping.