Information on Surface condensers

[malcolmd]

Due to my generally weak-willed nature, I acquired at an SBA Auction the internals of what I assume is a surface condenser - links to pictures are provided below...

Because the Leak compound I am building comes with an Edwards Air Pump I think a surface condenser will be a better option than a hull condenser (due to the need for the pump to be the "bottom" of the system.

My questions to the "brains trust" are:
1 - is it the steam or the cooling water that passes thru the tubes?
2 - how big a condenser will I need (for the smaller leak compound), and does the condenser and engine need to be accurately matched, or can this be managed by adjusting the amount of cooling water?
3 - as I only have the tube nest, does anyone know what the rest of the condenser looked like... clearly there needs to be an enclosing vessel (which will need to be able to contain the vacuum, if the water passes thru the tubes), and one can see from the pictures that one end of the nest has a nice flange to which this and a manifold for the open tube ends can be tightly affixed and sealed, but the other end appears to be lacking any structure to allow the vessel and tube nest manifold to be effectively secured and sealed, having only 4 bolt holes... Does anyone have any pictures?

Links to images:
The rule in the pictures is a 7" one...

lower view of condenser
top view of condenser
side view of condenser

thankyou!

[fredrosse]

1 - is it the steam or the cooling water that passes thru the tubes? ANS; For at least the last 120 years the steam is condensed on the outside of the tubes. I mention this because in the early steam naval years, the British Admaralty practice condensed the steam inside the tubes, but that soon was recognized as a difficult situiation, too much fouling on the shell side of the condenser, and difficult to clean.
2 - how big a condenser will I need (for the smaller leak compound), and does the condenser and engine need to be accurately matched, or can this be managed by adjusting the amount of cooling water? ANS; An oversized condenser is OK, and it looks as if your condenser is big enough for a 20+ horsepower engine. Generally about 1 to 2 square feet heat transfer surface area (outside tubes area) per horsepower is adequate for launch engines.
3 - as I only have the tube nest, does anyone know what the rest of the condenser looked like... clearly there needs to be an enclosing vessel (which will need to be able to contain the vacuum, if the water passes thru the tubes), and one can see from the pictures that one end of the nest has a nice flange to which this and a manifold for the open tube ends can be tightly affixed and sealed, but the other end appears to be lacking any structure to allow the vessel and tube nest manifold to be effectively secured and sealed, having only 4 bolt holes... Does anyone have any pictures? ANS; Will make a sketch and reply here soon.

Fred Rosse, Steam Surface Condenser Consultant for URS / AECOM, Power Plants Division

[Lopez Mike]

What a monster. Calculate the area before you decide to how use it. I dunno how you would reduce the effectiveness other than reducing the cooling water flow.

I have a little over one square foot of keel cooler/condenser on my approximately five h.p. engine (no vacuum pump) and only at full snot does the water returning to the hot well get hot enough to avoid with your finger.

[malcolmd]

Fred/Mike thanks for great information....

[steamboatjack]

Malcolm,
Like Fred I would say this is too big by a factor of 2 or 3!
The end without a flange is the expansion end, this is fitted with a packed gland around it as part of the shell to allow the nest to expand a different amount than the shell.
The four tapped holes would be to hold the outlet water box as this is obviously a single pass heat exchanger. I would guess by the size of the tubes that this was a liquid to liquid heat exchanger i.e. water/oil or water/water rather than a condenser although it would probably work OK in that duty.

I have seen Bowman marine oil coolers used for this duty, these are available from ASAP-supplies.com or sometimes from boat scrappers, you would have to carefully calculate the heat transfer rate. Don't forget that a surface condenser also needs a circulating pump, makes you wonder if its worth it on a small boat.

Regards
Jack

[malcolmd]

Ah, that makes sense Jack... (packed gland etc.), yes we will need a circulating pump, but I have a number of "part made" engines around which could be pressed into service

[Lopez Mike]

I concur with Jack about the extra pump. If you are trying to avoid the 'complexity' of a keel type condenser you are replacing it with an almost certainly less reliable system. Hard to imagine a simpler condenser than a simple copper pipe nestled up along side your keel.

Think of the engine room space you will be eating up with that rum keg and the extra pump!

[malcolmd]

Mike, as your signature eloquently explains, we don't do it because it's simple Imagine all the extra "tinkering" I will have .... either way I am a long way from having something to install it all in, let alone run it, so I will make my decisions when the time comes! Thanks for the input though, it all helps....

Mal

[Lopez Mike]

Consider ALL advice from me in light of the fact that I think a reliable version of The African Queen is the optimal craft.

Barbarous, I know.

[malcolmd]