DE for filter press

[ollieman]

We just purchased a 7" short bank filter press. We were told in the beginning to put 2-3 cups to 2-3 gals syrup when we first start this up. Well it did not go through and had to empty press and save until filter syrup. Then we were told that we did not put enough in and to add a lot more, were told you can't put in too much, Really. So the second batch we had about 3 gals syrup and the first batch which need to be re filtered. I put in 12 cups and it barely pushed any thing through. So then we were told that I put in too much, really you think, why would you tell someone you can't put too much, didn't seem right to me but I didn't know . So no instructions I have found seem to tell how much to use. Can anyone that has one of these tell me how much to use for different amounts of syrup. It would seem to me that all of these companies should have charts that are approximate amounts to use, they have been in this business long enough to know how much to use Thanks

[lpakiz]

The way DE works is that, in itself, DE is very porous. Straight DE will never stop the flow of syrup, until the window plates fill up full. The idea of DE is to keep depositing a permeable layer on the papers and building that layer back out. The dirt will lodge in the DE and not go thru into the clean syrup channel. If too much dirt deposits onto the face of the DE, it will plug. You need enough DE along with the dirt so that the layer stays permeable, until the plate is full. Then you are done until you break the press down.

The amount of DE you need is very dependant on how much impurity you have to remove. Whoever told you you can't put too much in was right. It's just that the press will fill prematurely and you wont get many gallons thru before the window plates are chuck full, and then flow stops, pressure goes up and you need to break down the press, clean it, install clean papers and start again.
Sometimes one plate is installed wrong. I do this at least once a season. Then the press has reduced capacity, depending on where the wrong plate was installed.
When it stopped flowing, were the window plates full to solid, or was there space in the window plates?
If it stopped flowing and there was space between the 2 layers of DE in the window plate, then you did not use enough for that dirt load. If the DE was solid, the press was full. When it's full, it's full! You need to stop and clean it.
It's a balancing act between too much (premature plugging due to plates full of too-clean DE) and too little (plugging because the dirt built up too fast on the DE layer and plugged the flow before the plate was full.
And the syrup has to be HOT (185 or more) to filter very well. There must be thousands of filter presses in use, and they do work. So if you still have trouble, ask again. I know we can get it to work. When it does, you will be a very happy camper I promise.

[Ski Bum]

Recommendations from Proctor Maple are 40 gallons of syrup = 5 cups D.E. for a 7" plate press. You may need more D.E. for dark or late season syrup. This info came from a flyer on proper plate filter press operation put out by University of Vermont & Proctor Maple. Hope that helps

[mellondome]

You need to know how much de your press will hold. To do this, use just water. Set the press up as you would for syrup. Pump the water through the press and back to the origin container. While doing this, keep adding de until the pressure spikes and flow stops. This indicates that the plates are full. Break down the press and save the cake ( filteraide in the press) let it dry and break it ip so it is loose again. Now measure it. And always remember this amount. Your press will never hold any more than this amount.
With a short bank , it will not take more than a cup to coat the papers to start filtering. Put a cup in with a couple gallons of hot syrup and recirculate it back to the origin container until it has all had a chance to go through the press and is sparkly clean. Then add what you need to filter with more de and filter into your destination container. It will take trial and error to know how much de to add at a time while filtering. If you dont use enough, your pressure will start increasing. Make sure you mix it well before filtering.
Start with a cup of de per 3 gallons of syrup and go from there. Later season syrup will require more de per gallon.

[JoeJ]

There is a thread from 3-16-2015, "How much diatomeaceous to use" that has calculations to figure how much to start with depending on the thickness of your plates and the number of plates.

Joe

[ollieman]

Believe me the plates were full of DE, packed full side to side and the papers had very little dirt on them. Knocked them out it a garbage can. It was dark syrup but never had a chance to really filter and it was hot we keep the burner on and just under a boil when we started.

[maple flats]

For a short bank (3 sections) 7" press, I started with about 1.5-2 gal of hot syrup. Then I mixed in 1.5 cups DE and ran it thru the filter and back into the mixing tank and kept recirculating for 3-4 minutes. Then I added the rest of the syrup to be filtered (up to 6 gal that my mix tank holds). I added 1/2 cup per gal, stirred well and then filtered. When I started this second time, I run it back into the mix tank until chrystal clear, then I move the discharge hose to my canner or bulk container without shutting the pump off, I just open the bypass valve, close the filter valve, move the clear syrup hose, then open the filter valve and finally close the recirculate hose. This works good on early season syrup, as the season gets old you need more DE. In use the press will let you know if you are doing it right. If the pressure climbs above 40 psi and you need to shut down, but the hollow plates have a filter cake on each side but a space in the middle, you used too little and the niter plugged the face of the filter cake. In that case, just use a little more next time, maybe add 1/4 cup DE/gal more. If the hollow plates fill up and the pressure tells you to clean the plates and change the papers, but the filter cake in the hollow plates is very light almost white, it means you used too much. In that case, just scale it back next time.
Once you find the right amount, continue to use that amount, both to start the first 1.5-2 gal to form a filter cake and then the amount you found works good/gal for the rest. This won't change much until you get to late season syrup, at that time you may get to the point where you may need 2x what you needed with early season syrup. Also, this changes year to year, some years you get more niter, others less, but there are very minimal changes during the season until you get towards the end.

[ollieman]

just so I understand, The first time I tried to filter I had 2-3 gals syrup and put in 3 cups and what I"m reading was that was to much because it was like it slammed shut and the pressure spiked to over 100 psi until I opened the by pass back. I guess I'm still a little confused.

[lpakiz]

Ollieman,
3 cups would not fill the press up. Something else happened there.
When the pressure spiked and you opened up the press, were the window plates full or part full? Was every window plate full to the same amount? Each window plate should have roughly the same amount of DE in it, whether it plugged from too much dirt load or just filled the window. All windows the same.
The idea with DE is that the DE actually filters the syrup, the papers just hold the DE back enough that it doesn't pass DE into the clean syrup. As soon as you get a layer of DE on the papers, you are filtering thru a layer of DE. The paper is not in the equation any more. Then the layer should get thicker and thicker with DE and dirt. If dirt plugs the face of the DE layer, there was not enough DE with that particular amount of syrup, so nothing will flow through. The you have to break it down and clean it.

[mellondome]

just so I understand, The first time I tried to filter I had 2-3 gals syrup and put in 3 cups and what I"m reading was that was to much because it was like it slammed shut and the pressure spiked to over 100 psi until I opened the by pass back. I guess I'm still a little confused.

Sounds like maybe a plate was in backwards? And when we say cups, we are talking measured cups from the kitchen utensil drawer. .. not red solo cups.

Did you get anything out of the discharge hose?

When you get info on filtering , it is worthwhile to take note what they are using. Probably a 10 " full bank, not a 7in short bank .

[jmayerl]

The one thing that everyone is forgetting to mention.....are you using DE from a maple supplier??? No, not all DE is the same. Just because it's good grade and you bought
It on the Internet or wherever. My buddy used my press last year and had the exact same problem as you and he said my press was junk. Turns out his DE he bought on eBay will not go through a press even though it looks and feels just like my from the maple supplier.

[Russell Lampron]

What I have found with my short bank press it that it will hold 9 cups of filter aid to fill it completely. I heat my syrup so that it is just under or at a boil when I begin filtering. I charge it with 2 cups of filter aid like everyone else and mix the needed amount of filter aid per gallons of syrup to be filtered, but not exceeding the 9 cups total, into the rest of the syrup. I keep stirring the hot syrup as I'm filtering to keep the filter aid suspended in the syrup. I start with 1 cup per 3 gallons in the tank and adjust that amount like Chris does depending on how dirty the syrup is.

Making sure that the press is assembled correctly, that the syrup is hot enough and the press properly charged are all important for a successful filtering session. Chris states that he shuts his press down and changes papers at 40psi but I go up to 80psi before I stop. If the hot syrup starts squirting out of the press between the plates you went too high! A little bubbling between the plates is normal and nothing to worry about.

[ollieman]

The press was assembled correctly. I had about 3gal of syrup just under boiling point. I drew off 1-2 gal into a pail and mixed in 3 measured cups of De that I got from a maple supplier. I then started the press with the suction hose in the pail along with the bypass hose and ran hot syrup threw on bypass to heat up pump. When pump was hot I took and slowly opened the filter valve and closed the bypass. It sucked the syrup into the filter and was slowly starting out the return hose when all of a sudden it stopped and the pressure spiked to over 100 psi. I went back to bypass and shut filter valve. Let it heat up again and tried to open filter valve and still would not go through. I opened up the filter there was maybe 1/4 " more or less of De on filter papers.

[plattmaple]

Did you wet your papers when you installed them? If you have a preheater hood just save some of the water that comes from the condensate drain to wet your papers. We use that water because it has no minerals or off flavor like our well water does. Syrup goes through our filter way better with wet filters.

[WESTMAPLES]

Did you wet your papers when you installed them? If you have a preheater hood just save some of the water that comes from the condensate drain to wet your papers. We use that water because it has no minerals or off flavor like our well water does. Syrup goes through our filter way better with wet filters. just read the replys, what plattmaple said is what i was going to add and this is exactly what i do, dry papers don`t work for me, dampen them for best results and do like everyone else said with the DE and you should have a great time filtering with less stress and more production

[wiam]

I wonder if your plumbing is plugged somewhere. Dry papers would not cause this. I have done dry or wet papers. I would try setting up the press and running clean water through the plates.

[lpakiz]

Yes, I have never wet the papers and never had problems like that.
I also would look at press assembly again. I know how easy it is to get one plate in backwards. If that one plate is near the inlet end of the press, not much will go thru before you are plugged. But Ollieman says the plates were partially full, so if EVERY window was partially full, it should have been assembled correctly.
I draw right from the boiling re-heat pan into the press, so it goes in HOT!
If the window plates were not chuck full, then one explanation is extraordinarily dirty syrup that plugged the filtering face with dirt/niter. Near the end of the season, you can get "ropey" syrup that won't go thru, but this is too early in the season for that, isn't it?

[Russell Lampron]

Yes, I have never wet the papers and never had problems like that.
I also would look at press assembly again. I know how easy it is to get one plate in backwards. If that one plate is near the inlet end of the press, not much will go thru before you are plugged. But Ollieman says the plates were partially full, so if EVERY window was partially full, it should have been assembled correctly.
I draw right from the boiling re-heat pan into the press, so it goes in HOT!
If the window plates were not chuck full, then one explanation is extraordinarily dirty syrup that plugged the filtering face with dirt/niter. Near the end of the season, you can get "ropey" syrup that won't go thru, but this is too early in the season for that, isn't it?

I wet the papers because they seal better when I assemble the press. My press originally had a hand pump and when I put an air operated diaphragm pump on it I found that it created too much pressure for the design of the press. I also put double papers on the outermost plate because of sealing issues. I didn't have problems with charging and filtering other than leakage with dry papers.

I have heard of ropey syrup at the start of the season but never had it happen to me. It usually happens at the end of the season when it's time to call it a season anyway.

[Russell Lampron]

The press was assembled correctly. I had about 3gal of syrup just under boiling point. I drew off 1-2 gal into a pail and mixed in 3 measured cups of De that I got from a maple supplier. I then started the press with the suction hose in the pail along with the bypass hose and ran hot syrup threw on bypass to heat up pump. When pump was hot I took and slowly opened the filter valve and closed the bypass. It sucked the syrup into the filter and was slowly starting out the return hose when all of a sudden it stopped and the pressure spiked to over 100 psi. I went back to bypass and shut filter valve. Let it heat up again and tried to open filter valve and still would not go through. I opened up the filter there was maybe 1/4 " more or less of De on filter papers.

Just reread this. You shouldn't need to heat up the pump first. Just open the valve to the press and run the syrup right through.

[mellondome]

Only other thought is that the de is not staying suspended in the syrup and you are sucking it all in at once. While filtering I try to keep the mix stirred the entire time.