Onboard Condenser

[JonRiley56]

Howdy All,

I pulled everything but the engine out of my boat over the break, it sure comes apart faster than it goes together..........

I skipped the condensation loop just to get in the water this year, but am putting together a condenser now. I have space under my rear seat so I am going with an inboard set up. I have 50 ft of 3/4 stainless tube coiled on a 3" radius, giving me a 6" coil. I am going to enclose it in 6" sched 40 PVC pipe. It slides in snugly so I dont have to worry too much about it vibrating and flopping around loosening things up. I have the two saddle fittings for me inlet and outlet pentetrations for pumping water through the assembly. (Expensive, but likely to save headaches, the have an O RIng seal ).

I need to figure out a way to bring the inlet and outlet pipe through the PVC cleanout endcap I will be using. Any ideas ? I though about drilling tight holes and then using 5200 or life caulk around them, but then wondered if ther might be some sort of compression fitting bulkhead that I could mount to the PVC cap and then attach the ss tube on the inside and not bring the stainless thru the cap itself.

I look forwad to your thoughts.

jon

[DetroiTug]

Jon,

These will work for that. Seal tights.

http://www.wireandsupply.com/SearchResu ... =1&cat=488

Price is right too!

Ron

[JonRiley56]

Hey Ron,

Those look interesting. Think they will be water tight ?

jon

P.S. - How are the pumps coming ?

[DetroiTug]

They have a solid rubber grommet and designed exactly like a packing gland. I've used them for electronics enclosures, never submersed, but if you look at how they are designed, they should be water tight.

-Ron

[fredrosse]

Sorry to say Jon there are two problems with your proposed condenser:

1. The shell of the condenser will have to endure at least 212F, and plastic will not work here. Although the condensing temperature while underway with a decent vacuum will be significantly lower, when just starting up the steam will be 212F. Steel, copper, brass would be OK here.

2. The coil is very nice, and in my opinion would make a good economizer coil to be placed into the stack, but the flow area available for cooling water in condenser service is way too little. The cooling water flow should be on the order of 30 - 50 times the feedwater flow, for your steam plant something like 10 US Gallons per minute (GPM). This flowrate is far too high for the coil shown, I think. Hook up the coil to a hose and see what pressure you need to force 10 GPM through the coil, if it is more than a couple of PSI then your circulating pump will use too much power.

[JonRiley56]

Hi Fred,

Good to hear from you. I trust you are well. Tell John Paul I said Hi. Hopefully his truck is back on the road
.
I was planning on routing the steam through the stainless coil, and pumping seawater through the pipe to cool the coil using a battery driven washdown or livewell pump. I will bring seawater in through the bottom on one end andout through the top on.the other end. It will then dump overboard.

I was hoping that the combination of heat loss in the 8 ft or so between the engine and the condenser, the typically low.temp.of.my cooling.water, and theheat sink.of.the 4 gallons or so of water in the condenser would let me get away with the schedule 40 pvc as a shell.

thoughts ?

[fredrosse]

Thanks and best wishes to you and yours for the new year.

OK, looks like I understood this backward! The concept you describe seems OK, provided the tube inside diameter is big enough for your steam engine exhaust. Sort of like a "Keel Condenser" inside a plastic container, with circulating water. What is the inside diameter of your stainless steel coil tube?

[JonRiley56]

Hi Fred,

it is 3/4" 409 stainless tube. 50 feet of it.

I was thinking if the back pressure was too high I could put a pump on the return side to the hotwell and drive it using the pulley I had for the water supply pump you saw on the boat. I am replacing that with the small steam pump that Ron is finishing up for me.

jon

[Oilking]

Jon
The seal offs, that Ron shows, should work as long as the rubber is up to the exhuast temp. Note that these are aluminum. If you're not operating around salt water maybe okay? I had fittings like this in the clearwell of a water treatment plant that disintegrate in about four years, leaving float switches hanging by the conductors. You might look for them in stainless. I know they are available, but I don't have a cost or supplier off the top.

There are also brass water service compression by IPS that could be made to work depending on whether you have copper tube size (CTS) or IPS for your coil. About $20 ea.

The coil is a beauty!
Dave

[farmerden]

Beautiful coil! Did you take any pics to show us how you made it? Den