Cider press

[patrickg]

I have a 20 ton hydraulic shop press. And real soon now I will have more pears than I can eat or easily give away (9 really large old, 100 yrs?) pear trees. I like cooked pears, pear butter, pear sauce (if you do it with apples I can do it with my pears as they are crisp and firm fleshed, not soft llike a bartlet) They are very sweet and juicy and should make good juice/cider.

I was thinking of, at least, temporarily replacing the 20 ton hand pumped bottle jack that powers my press with a air powered jack or a ram connected possibly to the remote hydraulics on the Kubota L4610 to lessen the manual labor that would be required to pump the handle about 127.382 kadrilion jilion times to make several galons of juice.

I have a good handle on how to make the fruit press attachment for the press as far as the "platten" and container with holes to let the juice out. Lots of info on cider presses available and I can duplicate for pear squeezing. No recommendations were noted for hydraulic rams or air powered jacks with appropriately long throw. I'm guessing that for conveninece at least a foot of throw would be good (many many pumps for a HD jack's handle).

I guess I'm missing two kinds of info. I don't know how many PSI is required as a minimum which prevents me building the "squeeze box?". Once I know the PSI requirement, and have the force available from the ram/jack whatever, I can compute the max area of the "platten" and get started cutting, grinding, welding, grinding, etc. And I don't know what sort of specs and asvailability there is for for economical rams or air jacks. To not overstress the frame of the press, I don't think I should exceed the 20 tons it was designed for by much if any.

Any suggestions?

Patrick

 

[GarageSmoker]

Take your pears to a juicer /w3tcompact/icons/laugh.gif.

I can't wait to see this one answered. I am constantly amazed at the information that can be gathered on this board. I plan on planting some citrus trees on the land so maybe this thread will prove valuable to me in the future.

Good Luck with the pear wine...I mean juice;

GS

 

[Anonymous Poster]

The last cider press I had access to used a 6" diameter ram, and built to 2000psi at full pressure. This pressure was applied to a 24x24" press plate, pushing against 10 sheets of pulp in a PVC lined tub.
If my math is correct, there are about 100 [ounds per square inch of pressure on the apple mush at full pressure.
A few things to bear in mind, the pulp is contained in what looks like a giant shop rag folded back on itself, after being ground to a size about that of a pea. Pressing a rack of cider usually takes about 45 minutes before all the juice is extracted.
The second thing is that hydraulic systems used in food processing should use food grade mineral oil.

 

[patrickg]

Frantz and GS (Every time I see GS I think Girl Scout but that might not be wrong...)

Anyway, Frantz I wasn't entirely clear about your numbers. I didn't follow the 2000psi to 100psi. If the 2000 was lbs of force not psi pressing on the 6 inch diameter "squeezer" then with that 28.27 sq in squeezer( 6 in dia) and 2000 lbs you'd have about 70.75 psi on the fruit. Let me know if I guessed right at the setup or straighten me out if I got it wrong.

I can size the length of the ram/jack and I know the force I want, about 20 Tons or 40,000 lbs so as not to exceed the design strength of the press BUT I don't know how big I should make the fruit squeezing squeezer's "foot" to get that required/desired psi and this effects the volume I can squeeze per cycle as well.

If 100 psi is enough then 400 sq in would be the max area of the squeezer foot thingy which is a rectangle 20" by 20" or a circle about 11.3" in diameter. If I guessed the math correctly then I could see how 10" ID heavy wall PVC pipe would make a decent cylinder and then I just need to figure out the practical height (length of pipe) that would work.

From some reading I did, I got a great suggestion for preping the pears for squeezing. Take the formica covered cutout from a large sink installation and mount a garbage disposal in it and put legs on it with an arrangement underneath to hold a large plastic bucket. Toss the washed fruit whole through the running disposal and let it collect in a trash bag lined bucket with an unbleached muslin bag (no colors, no decorations, or writing) inside of the plastic bag. This does not crush the seeds and works great with apples. The author suggested that used disposals in good working condition were a great bargain but the aesthetics usually precludes their use even though they could be sterilized. I'll' probably have to buy new to keep piece in the family.

You then drain the muslin bag for a few seconds (squeezing is OK) then place the muslin bag in the press and fold the top over to seal it and lower the boom on it. Supposedly if you press it hard enough the residue is pretty dry and about the consistency of damp cardboard. The residue might be appreciated by cattle. You think?

Anyway, don't hold back, I would rather find out about any misconceptions or dumb notions before building it, not after.

Patrick

 

[DocHeb]

You might be over-engineering a bit. I'm sure the presses they sell for home use don't develop near the psi that your hydraulic device would. See <A target="_blank" HREF=http://www.pleasanthillgrain.com/jaffrey_press.html>Jaffrey Cider Press</A>.

 

[Anonymous Poster]

OK, went over the figures again, using cheap & dirty math.
A 6" cyl will be 28.26 sq" on the end above the rod, and at 2000# of pressure, that should develope 56,520# of force on the piston. I figured on a 24 x 24" plate, = 576 sq" pushing on the fruit pulp. 576 sq" of plate with 56,520 # of force behind it has 98.12#/sq" of force on the plate, if the math I learned at moma's knee still works.
A garbage disposal would make an excellent fruit grinder, but I gotta ask, just how many bushels are you planning to process? Unless you're doing one heck of a lot, I think you might be better off using an old fashioned meat grinder with a coarse grate. You don't have to pulp the fruit much smaller than a pea to squeeze it.
As to the bag setup, most of the ones I see use a sheet, like a shop rag, that is about 5' square. The sheet is laid out on the base plate, and a pile of pulp that covers about 18" diameter roughly 3" thick is placed in the center. Then the 4 corners are brought in past center to keep the pulp in place. Additional sheets, usually 5 of them, are piled atop the first, and then the pressure is applied. There are no sideplates involved in a large press.
By bringing the pressing plate down slowly, the juice squeezes out thru the cloth nicely. Cider presses do not move quickly, too fast will blow a hole in the cloth bag, and cleaning up that mess won't be fun. I'm also told you get more juice with slow pressing.
As far as feeding the pulp to cattle after pressing, it could go either way. Since most of the sugar will be squeezed out with the juice cattle might not be too interested. If you leave a little sugar in, and let it ferment a bit, you might have very happy cattle. Hard to say till you try it.

 

[patrickg]

DocHeb,

I read a piece by a guy who uses a hydraulic mechanics press for a cider press. That is where I got the garbage disposal idea. He has done that and reports great success. He recommended mechanics presses from Harbor Freight and said they had a couple good ones for the $ in 12 ton and 20 ton but if space and $ were not prohibitive to go for the 20 ton. I did. Used it a few times as a mechanics press but am standing by to make a cider press accessory for it.

The 20 ton bottle jack takes a lot of strokes to go very far so I thought I would use a air/hydraulic jack or a ram to speed things up and not be so tedious. I can allways use the jack or ram for other things as I will encapsulate it with plastic sheeting rather than use food grade mineral oil and use it for other things as well.

I have 9 100 year old LARGE trees that inundate us in wonderful pears and I would like to not spend an inordinate amount of time sqeezing a small volume of juice. I haven't measured the trees but some are about 2 ft in diameter and a 20 ft extension ladder with me (at 6'2") standing at the top holding on to a branch with one hand and still not able to reach the copious quantities of pears above my reach.

I topped one of the trees drastically to reduce the excessive height and it came back with a vengence with new growth but did not bloom at all. Shocked its system I suppose. Read where trees that haven't been pruned for a while shold be cut back a little each year NOT all at once. Now I know!

Anyway, thanks for the URL. Last year I searched the web pretty good and saw a lot of cider presses. This is a nice one but at $500 I think I will spend another couple hundrred or less on what I have started and do as well if not better.

I'm only stalled for lack of a real good feel for the psi required.

Patrick

 

[patrickg]

Franz, Thanks for taking the time and trouble to kick this around with me. Your math is impecable, you are a credit to your mom's math teaching skill BUT your physics/engineering analysis is flawed or I need a drawing of what you are thinking about.

My take on this is that there is 2000 lbs of force being DISTRIBUTED over a 6 inch diameter disk. We agree on the area of the disk. 2000lbs. / 28.26 sq in = 70.7lbs per sq in. So we have about 71 psi of pressure on the fruit.

It isn't what I think we were discussing but if you had 2000 psi acting on a piston 6" in diameter the piston would exert a force of 56,520 lbs.

I'm still not sure how many psi are required to sufficiently squeeze pears but when I find out I can then make the largest pressure container the area of which when divided into 20 tons (40,000 lbs) will be equal to that psi requirement. I don't want to drastically undersize the container just to get enough force to exceed any reasonable requirement as for example, quadrupling the psi will make the diameter of the container 1/2 as big. I don't want to arbitrarily reduce my through put out of ignorance so I will try to find out a reasonable figure for psi and build to that.

About my terrifically accurate scale drawing... if 2000 lbs pushing down produced 56,520 pounds of force distributed over the area of 28.26 sq in that would be 56,520 lbs / 28.26 sq in or 2000 psi. Wouldn't that leave a net upward force of 54,520 lbs unapposed and nearly launch the 2000 lb weight into orbit?

Didn't mean this to be a physics/engineering lesson or a sense of humor test but I guess it ended up a bit of both.

Forgive me, attribute it to my advanced age, I'm having a birthday tomorrow!

Patrick

 

[Anonymous Poster]

OK Patrick, I think I know where you're getting messed up here. Basicly, " My take on this is that there is 2000 lbs of force being DISTRIBUTED over a 6 inch diameter disk. We agree on the area of the disk. 2000lbs. / 28.26 sq in = 70.7lbs per sq in. So we have about 71 psi of pressure on the fruit." you're dividing when you should be multiplying.
Each square inch of the cylinder piston has 2000# of pressure acting on it, so the piston rod will have a total force of 56,520# of output force, rather than 71# of force.
My physics then calculates the end of the piston pushing against a plate on top of the fruit that is 24" square, totalling 576 square inches. The resulting in a fruit crushing force of 56520# + the weight of the force plate would result in a force of 98.12# per square inch of force on the fruit mush.
The press I'm referring to is structurally equivalent to a mechanic's press with a shower base at the bottom to catch the drippings.
Now, about the age thing, don't let it concern you, I never expected to get this old, and while getting here has been a chalenge on occasion, the journey has left me with one he!! of a Rolodex of accumulated knowledge.
Worst case scenario, I have a buddy in Ok City with the Army, and he can swing by and crush your fruit with a large heavy engineering vehicle.

 

[Egon]

Patrick:
Have you considered a "lever system " The bottle jack could be placed outside the fruit/juice containment area so no adverse contamination takes place.

If'n your retired there ain't no more birthdays!
Egon