The Sabino Compound Engine

[crueby]

Dave, okay if I post one or two of the pictures of Greg's wonderful model that you sent me?
Chris

[steamer]

Not a problem

[steamer]

And sorry for muddying up your build....I'll go back in my hole.... 

[crueby]

And sorry for muddying up your build....I'll go back in my hole.... 

Not at all, chime in!!

[crueby]

Here is a picture of the beatiful model that Greg made - amazing that it lets the front side of the engine block be removed, its visible over on the right of the picture:

Also, a shot I found that shows the pistons and valves in the real engine removed and out on a bench - I used this to scale from and get some of the dimensions, knowing the piston diameters I could analyze and determine the sizes on the valves (doing digital image processing algorithms at Kodak for decades had to be worth something!)

[Jo]

  That HP piston looks thicker than the LP one. Or is it that it is partially dismantled 

Jo

[Charles Lamont]

That is an interesting arrangement of the valves and porting. From what I can see, it looks as though the HP valve is inside admission and the LP outside, allowing short, direct transfer passages linked by a vertical communicating passage.

[crueby]

That HP piston looks thicker than the LP one. Or is it that it is partially dismantled 

Jo

Even accounting for the HP piston being partially unbolted, I measure it the HP piston is thicker, and it has two piston rings where the LP has one.
It would have been interesting to pull them out when we were there for measuring the engine, but the museum worker keeping an eye on us was bigger than me.... 

[crueby]

That is an interesting arrangement of the valves and porting. From what I can see, it looks as though the HP valve is inside admission and the LP outside, allowing short, direct transfer passages linked by a vertical communicating passage.

Hi Charles, 

Thats correct! Here is the schematic view of the passages that I drew for the plans - this shows the general layout only, the passages in this drawing are not scaled and not in actual positions. The steam inlet on the real engine is in the center of thevalve on the front side of the HP engine block, the exhaust is on the back side of the LP block. That center passage connecting the top/bottom ones also acts as some extra receiver volume - there are no external pipes between the cylinders like is seen on a lot of compound marine engines.
Chris

[crueby]

Yesterday I worked out the holding jig for milling in the arcs on the cross rails. A piece of bar, drilled with holes to match the ones in the rails, and bolted to the tooling plate on the rotary table. Got lucky that the bar wound up positioned over a row of the plate holes, so it was easy to bolt it down. I made the bolt holes in the bar oversize so I could adjust the position to get the arc to line up just right on the first one, then with the bolts tightened down all the rails were held in the same position for milling the arcs. The rails are held a little above the table top, so the end mill did not dig into the table.

First arc complete...

So far three rails shaped, leaving the one with the thrust bearing ears for last. That one will take a couple extra steps. I'll mill in the arc as far as possible, then come back with a smaller diameter end mill to get close to the inside corners, final cleanup will need to be done in the mill vise.

[crueby]

Got the fourth cross rail shaped, drilled the holes for the thrust bearing mounts and used a smaller end mill to trim in closer to the 'ears'.




the parts so far. I think next time will start notching the bottoms of the side rails to take the cross rails...

[steamer]

That is an interesting arrangement of the valves and porting. From what I can see, it looks as though the HP valve is inside admission and the LP outside, allowing short, direct transfer passages linked by a vertical communicating passage.

Correct.   That keeps boiler pressure and  condensor vacuum off the valve and piston rod glands...It's easier on the glands and the rods as you don't need to tighten them up so much.

[derekwarner]

Chris, those steam driven Duplex pumps of the original vessel are interesting, so maybe a question for steamer Dan if I may.......

A few assumptions......going from astern..

The red pump....could this be an original pump as installed, and now used as a standby for seawater to condenser cooling?
The blue pump ......a replacement for a worn out original red pump, and currently used as the seawater to condenser cooling?
The green pump .....don't know...except to say the double head gasket on the pipe near the blue pump is of 3 bolt punched so must be for the green pump?

All of the small bore pipework & assorted elbows & unions is pretty messy...  typical....just get it piped up for now, will tidy it in the future
The triangular wooden mountings are certainly substantial 

So, what is the function of the green pump?

Derek

[steamer]

Chris, those steam driven Duplex pumps of the original vessel are interesting, so maybe a question for steamer Dan if I may.......

A few assumptions......going from astern..

The red pump....could this be an original pump as installed, and now used as a standby for seawater to condenser cooling?
The blue pump ......a replacement for a worn out original red pump, and currently used as the seawater to condenser cooling?
The green pump .....don't know...except to say the double head gasket on the pipe near the blue pump is of 3 bolt punched so must be for the green pump?

All of the small bore pipework & assorted elbows & unions is pretty messy...  typical....just get it piped up for now, will tidy it in the future
The triangular wooden mountings are certainly substantial 

So, what is the function of the green pump?

Derek

Hi Derreek    How are you?    I always look forward to your warm supportive comments!

The Green pump is a wet air pump.    The condenser on Sabino is a keel condenser.  18 in Hg is ideal.
The Blue pump is the bilge pump.
The Red pump is a fire fighting pump  ( Sabino is a CG registered fire fighting vessel...though if the fire is any bigger than your charcoal grill, you better hope the fire department shows up first)
The fire fighting pump is also plumbed to be used for boiler feed in an emergency.   It can take water from the forward 600 gallon tank, or from the water we float in, which is pretty brackish.
The boiler feed pump is on the port side out of view
Out of view and amidships is a Locomotive turbine generator which runs open exhaust, and uses more steam than the rest of the plant combined, but works well and will get us to port in the middle of the night if there is a battery problem.    Never needed to use it, but it worked well under normal tests

We follow the old doctrine of having 3 ways of getting water into the boiler.    The third, which is used a lot is an injector, also on the port side next to the coal scuttle.

Sabino for the years I was on her, and from when these pictures were taken, ran 14 hours a day, 7 days a week from May to October.  Half hours runs on the hour and up to some times three 2 hour charters at the end of the day.     

She was extremely reliable, because she was simple.    and rugged.

Dave

[crueby]

Sounds like a good place to put up these pictures - when Ron and I were there for measurement day, I took a series of pictures while standing by the engine, looking outwards under the deck. They start looking towards the starboard side, and rotate around the stern to looking down the other side of the engine on the port side. Quite a lot of machinery and piping there!  Here is the sequence, could probably have been merged into a panoramic shot:













Chris