new approach => pyramidal instead conical Fermenter

Hi@all,
after a brief and long search along several forums and boards on homebrewing, I decided to become a member here which seems to be the most competent..!!!

Well, I want to upgrade my equipment with two new fermenter, but these are dammed expensive here in Europe (80Liters for just 1700 Euro). So I decided to build them on my own.

But it seems o be rather difficult to weld a conical fermenter. I.e. to hold everything in place while welding. Today I had also done a search on grain mills, and because of them I came across my new new idea. Okay, it seems to be new, because I didn't find something like my idea on the web. But it is possible that this idea will just waste money, so I need your comments

It is no big problem to weld along a straight line, so why don't use straight lines on a fermenter - so I got the idea to use a pyramidal design instead a conical...


I had drawn to views from the top, the right one has a square plae as bottom, so it is easier to install a valve...


What do you think about that idea...????

About a stand and the lid I really love the Yuri's idea in his DIY Conical Fermenter thread.


kind regards from Bavaria
Steve

I LIKE IT ! It's problem solving like this that sets us apart from the apes.

I've been considering the idea as well. I think it should work fine. You will want to have the welds very smooth in those corners. You will also want to make the design so that it's actually feasible to weld it; keeping the height to width ratio to something easy to work with in the building process... as well as the cleaning task.

I think the only advantage of a conical as opposed to your design would be the crevices of your bends/joints- just make sure you clean/sanitize it well and I think you have a winner!

how do you plan on cleaning/ grinding the corner welds? That's part of the reason we use a conical shape, no places for nasty buggers to hide in welds we couldn't grind smooth.

Also this requires a lot more welding. With the conical design you have the seem of the cone (if you are making it entirely from sheets) and the seem of the cylinder and the joint where they meet. The square design has ~4 times that. The welding on the cylindro-conical should be easier too. You're basically doing flat welds except for the joint between the cone and cylinder. With the square design you have a bunch of 90˚ welds.
Then there is the difficulty of the dump valve, square hole, round peg.
What kind of welding would you use? It should be easy enough (meaning, not impossible) to set up the metal for welding with aluminum tape and c-clamps. You should even consider making a wooden jig to hold it all in place while you tack it together.

You can do it with 1 weld, and the weld to attach it to rest- Could even be less welds if you have a large piece of material to work with; once top of the 'cone' attached to main portion, the rest of the cone one piece attached to that so that you can bend the four edges, tack the one side, and then tack the other three edges to the main vessel. Four weld lines- Just takes some planning.

If you made it out of a single sheet of metal, you could plan to make 3 full sides and two half sides on the ends. After bending and bringing the shape together, the weld will occur along a flat face, rather than in a corner. Easier to weld and grind.

Cheers

Hi,
sorry for the delay, but as you all know at this time of the year lots of partys have to be solved

Thank you for your suggestions. Well, you are right that my design require much more welding, even if I use one singe sheet which is bent into place, but the corners of the pyramidal section will still require lots of welding.

I also had found a nice tutorial on a conical fermenter out there in the web ( How to Build a Conical Fermentor Cheap ) but I still worry to bend the metal into the circles, if the metal is stressed while welding, I'm really sure it won't be tight. I don't have access to bending-rollers to bend it into place, that it will hold its shape without to be stressed...

bye
Steve

Seabee John said:

how do you plan on cleaning/ grinding the corner welds? That's part of the reason we use a conical shape, no places for nasty buggers to hide in welds we couldn't grind smooth.

Click to expand...

From a welders perspective, you wouldnt grind or clean the inside welds, and the reason is, it depends on how you weld it up. Now, if you were frabricate all four sides, and your tolerances were tight, and your fittup was tight, you could fuse weld the outside corners moving your tig torch in really tight circles no bigger than 1/8", using no filler, just fusing the corners. What this does is create a very smoothe and seamless inside seam, that would be so smooth, that it would look like the fermenter was made out of one piece. I've done fuse welds like this, time and time again, but on a project like this, I dont recommend the first time tig welder try, or at least do a crap load of practice sample before you tackle the real project.

Bavarian_ambassador said:

I also had found a nice tutorial on a conical fermenter out there in the web ( How to Build a Conical Fermentor Cheap ) but I still worry to bend the metal into the circles, if the metal is stressed while welding

Click to expand...

Eeks. A copper fermenter? I would be much more worried about copper poisoning!

I really need to get myself a welding setup. It's posts like this really make we want to take the plunge.

I don't know much about any of this, but, from what i understand about conical fermenters, they use the cylindrical shape of the cone/fermenter to create a convection current in the fluid in order to get to the yeast and turb that would accumulate in the bottom most part of the cone. Would a square cone allow the same process?

hammer one said:

I LIKE IT ! It's problem solving like this that sets us apart from the apes.

Click to expand...

It's having problems that sets us apart too

Reading this thread got me interested in the mathematics of making a cone from a flat piece of metal, so I amused myself by working out some equations which may be of use to those who need to make a cone. In the link above (How to Build a Conical Fermentor Cheap) the cone was made from a semicircular template. This gives a fixed angle between the sides of the cone and the centerline of 30 degrees, for the end dimensions specified. I don't know what the standard is for conical fermentors, but it is easy enough to make a template to give whatever angle is desired; i.e., either a taller, more slender cone, or a shorter, fatter cone.

All cones can be made from a sector of an annulus - the area contained between two concentric circles, and between two radii extending out from the common center, cutting through both circles. Call the radius of the smaller circle r1 and the radius of the larger circle r2, and let theta be the angle between the two radii extending out from the center. The problem is, given the cone dimensions, to determine the values of r1, r2, and theta so you can cut the flat piece of metal for the cone.

Definitions:
D1 = the diameter of the small end of the cone
D2 = the diameter of the large end of the cone
H = the height of the cone, along its centerline
L = the length of the cone measured along the cone from end to end
phi = the angle which the side of the cone makes with the center line of the cone
NOTE: all angles in the following equations are measured in radians - multiply by 57.3 to convert to degrees, or divide by 57.3 to convert from degrees to radians.

Typically you will know D1, D2, and either H or phi. If you know H, then:
L = H^2 + ((D2-D1)/2)^2 and phi = arccos(H/L)

If you know D1, D2, and phi, then H = (D2-D1)/(2*tan(phi)), and L can then be determind as above, or also by L = H/cos(phi).

Now from D1, D2, and L, we can easily find r1, r2, and theta:

theta = (PI*(D2-D1))/L
r1 = (PI*D1)/theta
r2 = (PI*D2)/theta

Another useful calculation is to determine the minimum dimensions of the rectangular sheet from which the cone can be cut. These numbers can easily be obtained from r1, r2, and theta. There are four cases, depending on the value of theta:

Call the length of the two sides of the rectangle S1 and S2.

Note - angles here are in degrees

* theta < 90 degrees
S1 = r2 - r1*cos(theta)
S2 = r2*sin(theta)

* 90 <= theta <= 180
S1 = r2*(1+cos(180-theta))
S2 = r2

* 180 <= theta <= 270
S1 = 2*r2
S2 = r2*(1+sin(theta-180))

* 270 <= theta < 360
S1 = S2 = 2*r2

Disclaimer - I believe these equations are right, but the calculation was kind of "quick and dirty", so before you use them to cut an expensive piece of metal, remember - "Measure twice, cut once."

Interesting idea but, how bout this. Make it out of any metal you want, either round or square and instead of welding the joints use lead free silver solder. You could get your smooth inner joints without grinding them smooth. You could also leave a lip on the outside of the cone/cylinder/pyramid/square that could be used to clamp the joints together while soldering.

Heck be the first to have a transparent fermenter, you can do it with plastic and one of those plastic solvent glues, silicone or food grade epoxy. They have been building aquariums that way for years. It would be like caulking a bath tub.

The hardest part is going to be getting an air tight seal on what ever you use as a lid. How much pressure builds up inside a fermenter anyway? 5 to 10 psi?

Just my 2 cents, Pinworthy.