|
Post by pinhead on Dec 11, 2011 16:46:37 GMT -8
After a lot of reading and investigating, I completely agree with Donkey.
I'd use oil before water.
|
|
|
Post by pinhead on Dec 5, 2011 17:34:56 GMT -8
If I understand correctly, there are two predominant factors that effect the heat transfer of a bell: Surface area and convection. I believe convection is the "Brownian motion" that Karl mentioned. Inside the bell there will be both lsrge-scale convection and small scale convection that can very quickly move heat from the gasses to the relatively cool bell.
This Brownian motion is why fiber insulation is used to insulate the walls in your house; the insulation won't stop a draft, but will eliminate the convection that causes heat transfer.
|
|
|
Post by pinhead on Nov 11, 2011 15:36:37 GMT -8
The only thing I'd change is your transition from the secondary chamber to the exhaust; check out the Helpful Hint thread.
|
|
|
Post by pinhead on Nov 5, 2011 19:26:26 GMT -8
As a farm kid with plenty of welding experience, I can attest to the accuracy of this post.
I didn't realize that it had to get that hot, though, to create the vapor; I generally keep my nose away from the oxidizing pipe until it turns white and then after that don't worry about it. It's good to know that I've been overly cautious.
|
|
|
Post by pinhead on Nov 5, 2011 19:20:38 GMT -8
What are the dimensions of that barrel and where did you get it? The dimensions, from the top of my head, are: 15.9 U.S. liquid gallons, 15" diameter, 23" height. It is built as a pail, slightly conical and with a removable lid. I've bought it from a cask trading company in the Netherlands. I am willing to give you the address, but I don't see the relevance. Here it is: Goedhart Vatenhandel BV Spaarnwouderstraat 41/A 2011AB Haarlem I didn't realize you were in the Netherlands. Thanks, anyway!
|
|
|
Post by pinhead on Nov 4, 2011 10:31:18 GMT -8
What are the dimensions of that barrel and where did you get it?
|
|
|
Post by pinhead on Oct 31, 2011 12:04:23 GMT -8
|
|
|
Post by pinhead on Oct 29, 2011 17:33:27 GMT -8
Are these temperature readings inside of the burn chamber/heat riser or on the outer surface? I'm curious how well this combination of materials insulates...
|
|
|
Post by pinhead on Oct 28, 2011 12:20:53 GMT -8
One question: What percentage of the feed tube cross-sectional area comprises the secondary air inlet?
|
|
|
Post by pinhead on Oct 26, 2011 17:35:46 GMT -8
I've heard in HVAC systems, every 90° elbow is equivalent to 20 feet of straight pipe...
|
|
|
Post by pinhead on Oct 25, 2011 16:15:54 GMT -8
I burned for about an hour with paper. Once it stopped steaming I added some wood to get it to start steaming again. I added more wood each time it quit steaming until it was loaded to full capacity. Burned it like that for probably an hour when I ran out of wood.
|
|
|
Post by pinhead on Oct 24, 2011 22:40:07 GMT -8
I love your design! In fact, my prototype RMH has some of the same features as yours (I'm not as far along, though; I've just cast the burn chamber). What are you using to make your briquettes? Sawdust and paper? What are the dimensions of your RMH? It definitely has a strong draft even with both inlets open... In my experience (with a 6-inch system) if I leave the bottom inlet open the top inlet tends to smoke-back a little. Do you suppose you're getting stronger draft due to your tall exhaust pipe? Petersburg's Small-scale Development thread has some exhaust analyses included in his posts.
|
|
|
Post by pinhead on Oct 24, 2011 15:05:36 GMT -8
I fired the contraption this morning and the mixture seems to be working well and insulates better than expected. Heat-up takes slightly longer than the previous sheet metal/vermiculite design but that is to be expected. It steamed a lot more than I thought it would, but not excessively so. There weren't any pops or noises that I would expect from a "blow out" caused by a steam pocket. It still feels good and solid and is holding together well.
The heat riser is sheet metal insulated with vermiculite; I've only cast the burn chamber thus far.
|
|
|
Post by pinhead on Oct 21, 2011 16:27:47 GMT -8
The "mold" dried over night and firmed up really well. I'm going to let it sit for the rest of today and probably fire it tomorrow. Does anyone have any suggestions as to how quickly I should heat the mold? I suspect the vermiculite will be holding quite a bit of water and wonder if heating the entire mold above the boiling point will force the vermiculite to release the water in the form of steam and blow parts out...
|
|
|
Post by pinhead on Oct 21, 2011 0:02:08 GMT -8
I was watching RMH "workshop" videos on Youtube and found THIS one. I mixed the furnace cement, some water, and vermiculite like they showed at about 4:03 in the video. I'll let it dry for a couple of days and see how it holds up.
|
|