boardmaker said:
Spirilis,
I've done a fair amount of research and some prototyping. Here is what I can tell you. To make a briq. with hardwood sawdust, you will need roughly 24,000 psi. With that said, if the end or your briq that you are pressing against is 3x3, then you have 9 sqin. So, you will need 216,000 psi. Hardwood really does require that much pressure to get the lignin to successfully bind. I don't have softwood so I have no idea about it. Now, some presses use heat to help bind the dust so they don't need as much pressure. I don't prefer that. One, it's a fire hazard. Two, your product isn't nearly as dense. Most log splitters don't even put out 70,000psi. So lets say you have an 8" cyl. in your garage. To run it you will need a pump that will run at least 4300psi. Most log splitters top out at 3000psi. What I'm trying to say is that it will take a large cylinder and a good pump. Without 3 phase electric, it will have to run off an engine because you can't get enough hp out of single phase. I had a lot of my design built off of an ruf briquette press. And, I found out they have their infeed prepressure cylinder patented. What confuses me is that some companies have a machines that work very similar to theirs. I don't know enough about patents to know what I could legally get away with. I'm not looking for a lawsuit. If I had access to a machine shop, I would build one. I have all the basic tools. Welder, plasma, etc., but it still would require a lot of machining. The best way would be to make your cylinder part of the pressure rod. To make a reasonable priced custom cylinder would require access to a shop. I have stepped away from it for the time being. I have built some smaller prototypes with scraps rigged on a log splitter. I can make it work. But, it's not in my budget right now. And once it's built, if you find you built your infeed say to small, I would be depressed. I don't really see that being a problem, because with a plc you can change all of your timing and pressure setpoints instantly. But, as we all know there are unforseeable circumstances. If you decide to build one, or just tinker with it, let me know. I have done a lot of the hydraulic math for different combinations and such. Besides, you might have an idea I haven't thought of. I know most of this post is a let down, but if I had more time and 10 grand in my pocket. I would be ordering in parts tommorrow. It was good to see this post again. So does anyone have an idea they would like to share. I'd like to talk some more about this. I think a person could create a market for briqs. It would take a year or 2 to get where you need it to be profitable. Ya gotta start somewhere.
I think you are twisting force and pressure all around. Let me see if I can sort this out:
To make a brick you need 24,000 psi (we'll take this as accepted fact)
3"x3" brick = 9 square inches @ 24,000 psi = 216,000 pounds force
Most log splitters don't put out 70,000 psi - this should be pounds force. 70,000 pounds force = 35 tons
Most log splitters run 3,000 psi - True as an absolute maximum, though most pop off at ~2500-2700psi to reduce stress on components you would have to multiply the hydraulic pressure by the cylinder area to get pounds force.
an 8" dia cylinder = 50 square inches x 2500 psi = 125,000 pounds force, or x 2700 psi = 135,000 pounds force
As a basic rule - it seems you're looking for 24,000 psi on your brick. Most hydraulic systems would be conservatively 2400 psi, so you would need a a hydraulic cylinder area ~ 10x the area of the brick you wish to make
