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Operating pressure

Posted: Sun May 03, 2015 8:03 pm
by wsmcycle
I took the boat "fearless" out on the lake yesterday. I could not keep enough good fire in the boiler to keep 100# of steam. I have worked out my plumbing problems and now i face a new ignorance.
In the firebox, there is an elevated ring which stands two inches off the wall and and 8 inches up from the bottom of the ash box floor. The Grate is the same diameter as the ring. Problem! Charcoal and coal fall off of the outside of the grate, down into the ash box.
I have watched with much enthusiasm the video "little and Often". I know that i choked the fire with too much coal. I cleared out the excess coal thinking that very thing while still on the lake . It burned better but not enough good enough. I do not understand the firebox design. There is nothing to keep the grate centered on the ring either. There could be a 4 inch gap if the grate were pushed over to one side. If there were another ring that kept the coal from falling over the edge, I would think that the ring is a great answer to supplying secondary air but as it is, I don't get it. The coal just fills up the space between the wall and the grate.
The engine sounds good at 100#s, even 80#s, but the steam is too saturated at 40#s. Must have hotter steam to operate!
What an exciting day.


secondary problem
The Penberthy would only flow water out of the overflow. The old penberth did the same but i had a spare which I exchanged. Same result. I reasoned that perhaps the one-way valve leading from the injector to the boiler was blocked. I took it out and although it allowed passage the wrong way because of a bad rubber seat, it was not blocked in the forward direction.
I'm getting closer, but HELP please!
Wendell

Re: Operating pressure

Posted: Sun May 03, 2015 8:14 pm
by gondolier88
Wendell,

Sorry to hear your woes! A walkabout fire is a new one on me though. I'm afraid from the picture it simply looks like the grate is off centre, although by the sound of it there is more involved.

Penberthy; what is the working steam pressure range your injector is rated to? Are the steam supply pipe and the water delivery pipe of the same bore? How far is the I jector above the waterline? Is there a strainer on the water supply in to the injector? Are the injectors new or second-hand? Have you got a valve on the cold water supply to the I jector? Is the supply to the injector cold, or is it warm?

Greg

Re: Operating pressure

Posted: Sun May 03, 2015 8:24 pm
by wsmcycle
Greg
The supply water is cold from reservoir which is two feet lower than the injector (the flow is good). There is a valve in the supply line. I do not know the operating design pressure of the injector ( is see no serial number on it) but I have run injectors before and I recognize the audible change when they slip into gear. However, on this boat, both injectors I tried, have started a good flow out of the overflow port.
Have you seen one flow out of the overflow line?

Re: Operating pressure

Posted: Sun May 03, 2015 9:40 pm
by Jack Innes
Could the space causing the trouble be once taken up by firebrick or some type of liner?

Re: Operating pressure

Posted: Sun May 03, 2015 9:55 pm
by wsmcycle
That is a good idea Jack. That would make sense. Except that the previous owner would have to have removed them. I could put some kind of refractory in the space. Perhaps blocks. I thought I might cut some angle iron up and stick them vertically around the periphery.

Re: Operating pressure

Posted: Wed May 06, 2015 12:10 am
by Lopez Mike
If your check valve between the injector and the boiler is leaking, the back flow might be heating up the injector too much for it to work properly.

Try putting a rag soaked in cold water on the injector to see if it helps.

Re: Operating pressure

Posted: Wed May 06, 2015 1:44 pm
by wsmcycle
The check valve leading to the Penberthy was leaking as evidenced by dripping coming from the overflow port. I changed the valve with a new one. This stopped the leak. However, the flow was still coming out of the overflow. please check my attached picture for flow path.
I made a new grate which overcame the failings of the previous one. The air slots were so small, the ashes and bits choked the grate to near closed after running a short while. I took the boat out yesterday afternoon and the firebox was very improved. I could keep 100#s. YEEE HAW
Every venture has a problem and this time a rag sucked up into the chain drive for the boiler make-up pump and broke the chain. Once again, I am hand pumping to the boiler because the Penberthy (second backup) failed.

Is my flow path through the Penberthy correct?
Thanks
Wendell
penberthy.JPG
penberthy.JPG (43.63 KiB) Viewed 12602 times

Re: Operating pressure

Posted: Thu May 07, 2015 1:25 am
by steamdon-jr
Wendell, try closing the water supply off, turn steam valve on all the way and then quickly open water valve but with control, just to try to get it to grab, maybe it is too flooded if that can actually happen?....I have done this with some to "trick" the injector persay, however I have to say mine has worked flawlessly for 2 years and even sometimes bypass the pump and use it all day when taking visiting riders because it is more intersting than a bypass valve on the pump.

Re: Operating pressure

Posted: Fri May 08, 2015 10:03 pm
by SL Ethel
Easy diagnostic test for your injector: put a piece of hose on the overflow and stick the hose end in a bucket of water when you try the injector. There should be no bubbles. If you see bubbles, you are getting air in the suction side, and these injectors will not run with even a tiny air leak. It seems unlikely since you are not lifting water with the injector, but it's an easy test.

I think throttling the water inlet has already been suggested. Since you have an elevated water tank, maybe a wide open valve setting is just allowing more feed water to free flow into the injector than it can actually handle.

Have you had the injector apart to make sure it isn't missing any of the cones?

Cheers,
Scott

Re: Operating pressure

Posted: Fri May 08, 2015 10:49 pm
by Lopez Mike
I believe he IS lifting. About two feet. So a suction leak would be bad.