Piping for a Fireplace Grate

Try find odd lengths of heavy wall square tubing or drill pipe at scrap yard

common iron gas/water pipe will serve for this use. It should not be the support grid as cold air is drawn over it by the draft of the burning wood. It should be in the hot gas stream a few inches above the logs. You can place it in the logs as well. The cool air you force through it will prevent melt and sagging

I would estimate pipe like this will serve for 20 year or more. You may be able to find enough in a scrap yard. Then it will need to be cut and threaded and made into a grid.

A better bet is this commercial item. Why invent wheels. You can also get ideas here if you want to make your own

http://www.google.ca/search?hl=en&q=fireplace+%2B%22heat+reclaimer%22&btnG=Search&meta=

He wants to invent wheels or he'd buy a heat-tilater (:

My parents had on like this that worked well. The pipes were about the same as 2" automotive exhaust pipe.

From what I've seen on the market today, for one reason or another, none of them will work the way I need it to. I have a very large fireplace, for one. Cracker barrel style, I suppose. (if I could figure out how, I'd post a picture.) I designed it with two 2" pipe running from inside the hearth to inside the firebox. One intake and one return. I have a vent in and out of the sides of the hearth. I have a power outlet in the hearth connected to a switch on the wall. The fan will sit inside the hearth (and out of sight entirely). Also, of course, the lines will be out of sight. I don't like the units that are obvious and obstruct the beauty of the fire itself. (Personally, I don't see how anyone likes the exhaust valves sticking out of the fire like a hot rod exhaust.) It also limits severely the size of the fire you can build. So for practicality and aesthetics, I would like something less noticeable and less confining. I also would like to have doors that close when needed, and those units only work with open fireboxes. The units that are connected to doors themselves are not as effective as this will be, and are very obvious and do not look so good when you open the doors. Surprisingly, there is nothing on the market that I have found that meets my criteria. Hence my design of the better wheel.

Well that cleared the mud

I think I think iron pipe would suffice but clay pipe may be supperior to your application.

Mount your pipes in the very top of your fireplace so that they will be hidden. I have seen these on home improvement shows. There are fireplace inserts commercially available that do this as well. The intake and exhaust vents are located at the top of the fireplace as well and the blower is mounted on the intake side. When the grills are installed over them the vents are concealed. Put a few bends in your tubing to allow for thermal growth. The muffler tubing is what I would use. Being thin walled it would allow for rapid heat transfer. The heavier water / gas pipe would last longer but you would not get as much heat out of it.

I have a brother that rebuilt his waste oil burner (uses it every day in the winter). He used muffler tubing and it has been in service for at least 7 seasons with no problems. The replacement heat exchanger from the manufacturer was made out of even thinner material but not with in his budget.

Just a thought, build your grate and extend it upwards to support your heat exchanger. This will eliminate physically mounting anything to the inside of your fireplace. That will make for easy maintenance and repairs in the future as well as eliminating future problems from the mounting holes. Have swinging hooks on each side of the uprights for cooking. That will help camouflage what the extensions are really intended for. Be sure to provide some means to prevent tipping of the grate if you do use it for cooking. Do not rely on the weight of the logs to hold it.

Safety first.

I have seen a series of 7 or 8 two inch pipes bent in an open C shape and then welded to a frame with six inch legs on it. The pipe looked like 1/8" section.

The fire sat on the lower part of the C shaped pipe, which was horizontal. The back was a vertical run of about 18" high, perpendicular to the lower pipe run. The upper run was about a 60 degree bend from vertical and the pipe length here was long enough to bring the hot air out of the fireplace.

The problem with a fireplace is that, if the flue air is coming from the room you are trying to heat a large percentage of air is going up the chimney. The best way to use a fireplace to heat is to get your flue air ducted into the bottom of the fireplace from outside the house. A set of glass doors allows access to the fire and viewing plus keeps the room air from going up the chimney. A forced air or convection system then circulates room air around the fire box or through a hollow fire grate.

There are hollow forced air fire grates available at fireplace shops. With a set of glass doors on top of the forced air system you can get two of three done. Getting outside air into the fireplace might be tricky. If you have a ash door (a trap door in the bottom of the fire box) and a clean out in the basement then you can leave both open and duct cold air to the clean out door. Or just make the basement colder than it usually is. Basements are pretty leaky anyway, unless you've done a lot to seal the foundation to the house frame...

That's about the only way to actually gain heat in the whole house from a fireplace. Anything that allows interior air to go up the chimney will cool the other rooms of the house as much as you heat the room with the fireplace.

Hello fireplacequestion:

You will find this site very interetsing!

http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-2505/BAE-9437web.pdf

Well worth a visit! It deals with exactly the ideads you have in mind!

It may be that steel scaffold tube will surfice? Personally, if possible I would get some fire bricks and drill a little less than half the circumfrance from rows of bricks. Place the pipe in the botton half as you build it in and place the other half on brick over the scaffold tube. You could perhaps have three or more all fully enclosed by fire bricks with one or both ends coming out of the front of the fireplace. Make sure the have an inner grill and maybe an slightly proud of the fireplace front surface grill as well. Or you can arrange it so the pipes do not quite reach the face of the front of the fireplace wall, and fit a 'cupped' or raised grill over the whole of the three or four pipes. This hopefully will stop any burned fingers?

Cement in and make all secure before first firing. This will heat the bricks directly rather than the pipe, and there should be no worries of any 'sag' (know the feeling). And, the bricks will stay hot for a while after the fire is out keeping the warm air to the room making it even cosier.

Good luck and let us know how you get on please?

You know, I saw that article online. Some good info there. Ahhhh the internet.

I have ordered my material now, I'm using schedule 80 pipe and welding butts. Going to snake it back and forth in a plane with 90's welded together (since returns are ridiculously expensive for some odd reason). Will connect it into my existing lines through a reducer and these flex tubes: http://www.dmeexpansionjoints.com/flex-metal-hose.htm.

Then into a fan in the hearth. Very neat and clean. Anyone have any recommendations for a fan supplier? Quiet and powerful would be nice, but I am assuming I will have to choose between the two!

Hello fireplacequestion:

I was not able to get the site directly, so entered the main name and also entered 'Images' in google and this is 20 of 91 illustrations, 4.5 pages. You may already know of these because they well have been on the site, but I have not got to the site yet. I like the look of the sliding expantion joints.

Do you have any picture or drawing of the design? Or is it still in your mind?

Take care and good fire making!

Hello fireplacequestion:

I am not sure what you mean by a "cracker barrel" fireplace?

Is it like the old English fireplace which is about 1 yard deep and five or six foot wide by 4 or 5 foot high?

On the site I sent earlier there is mention of fans and build in log holders and 'natural' convector fireplaces/ What size fire and were you thinking of a flat fan in the hearth itself? Sorry, I used to be a builder but, I cannot envisage other peoples ideas? What size fan do you need and what type?

Will the hearth be raised from ground level?

Sorry for all the questions, I guess it should be you asking those?

One of the BEST efficiencies you can effect for a fireplace is to quit feeding it from room air. The air drawn up the chimney has to be replaced and that usually means pulling it under leaky doors and around leaky windows. Very hard to make that up with radiated heat or blown air.

Run the web until you find a pic of what I am talking about, but we are talking roughly a 1 1/2 in hole in the back wall of the fireplace to bring outside makeup air into the fire.

The technique is called a direct vent fireplace. Kind of scary, but you don't sound like you scare easily.

Yes, I agree. I guess I haven't addressed this issue clearly, but part of the reason I need a unit that works with doors (which negates that multi-bar C shaped unit that blows directly form the fireplace) is so I can close them and have the fire feed from my open ash doors in the firebox while the house air is closed off to it.

Also, I learned from the physics forum (http://www.physicsforums.com/showthread.php?p=2046420#post2046420), that my previous design has a flaw. If I make the line one continues snaking line with 180 turns all the way through, then there will be no fan on the market that could push air through something with that much static pressure. I'm glad a asked about this. I need to make the design in parallel instead of in series... feeding into an in manifold, running my pipes out of there, and collecting the hot air into a another manifold.

How do you post pictures on this board?

Hello fireplacequestion:

On reading your post # 16 I am a little confused...........

You say you want to close the doors on the fire, while feeding air to the fire via the open 'ash doors'? You mean the ash doors on the hearth?

In doing this, how is the 'house air' closed off? Or are your ash door/s on an external wall, which allows you to rake ash directly from the fireplace via the door/s leading to the garden?.........Not a very well phrased post, but I think you well get the drift?

If you can answer this I would be obliged. And I did not get the impression you were designing a fireplace with doors. Or did I read your first post wrongly?

Take care.............

Hello edignan:

how are you?......................Check out this site as listed in a previous post here. Look at Figure 2 - 9437-2. It illustrates your idea perfectly.

We had a house with concrete floors, and the fireplace was using a 'shared' chimney on an internal wall. But your idea could have easily been encompassed in the initial build. As you say the air which takes 95% of the heat up the chimney has to come from somewhere and an idea like yours, (far from a new one) is a necessity in modern virtually 'sealed' rooms with double glazing etc. It would be interesting to make a sealed 'room' of average size from thin ally or CU and see how long it took to implode? That is of course if the fire stayed alight long enough? I suppose you could achieve the same thing using card, from or very thin batten with sealed aluminium foil or plastic sheet as the 'room'. Or even build a scale model with scale fireplace? My verbal has turned to waffle (not unusual!) so, au revoir.

http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-2505/BAE-9437web.pdf

Take care..................

wouldn't a modified exhaust header from say an old motorbike do a bang up job?