Clogged pre-filter on a CDL vacuum filter

[WolfCreekMaple]

I was always told that using a vacuum filter won't allow you to filter MORE but just faster. In terms that your filters are going to get clogged at X gallons and need replacing regardless if your using a vacuum filter vs. gravity filtering. So maybe it's not the idea that you don't have enough DE or the filter but maybe just the fact that you need to change those filters more often and that you aren't going to get any more syrup thru those filters.

[jdircksen]

1/8 of a cup of DE is not enough. Put a full cup in and try it, if it works but not as good as you think it should, then try more. 1/8 of a cup is not enough to put a good layer on the filter to keep it from plugging.

Do you add it to the entire batch before putting syrup into the filter or add it once some syrup is sitting on top of the filter?

[WolfCreekMaple]

Do you add it to the entire batch before putting syrup into the filter or add it once some syrup is sitting on top of the filter?

Mix it in with the hot syrup.

[fred]

jacob everyone in the region is having trouble filtering. some of the 7" presses are only getting 5-10 gallons through before changing out and cleaning. looks like the same issue with you. every year is different

[jdircksen]

Ok here is an update. I made 5 quarts today and actually had what I'd call a success with the filtering process. I think Fred is right - this year is different. Seems like the niter is extra fine.

I made 2 changes on the unit.
1) only use 1 prefilter instead of 3 or 4
2) added the 1/2" ball valve ahead of my Tomlinson valve so I could close it to guaranty no air was getting sucked up the Tomlinson valve

Ended up filtering 3 times, but turned some ugly dark syrup (sap was cloudy after 2 days in the refrigerator) into clear syrup.
1) first pass without any DE. the syrup went through like a dream, but was very cloudy.
2) second pass with 2/3 cup of DE and it ended up clogging after 4 quarts, but was still a little cloudy. the filter had a solid cake on it.
3) replaced the filters this time and only used 1/3 cup of DE. had to run the vacuum for about 5 minutes but it all went through eventually.

seems like my issue is that I was using too many prefilters, but I'll continue to test the other theory that the Tomlinson valve lets air in.

[GeorgianBaySugarCo]

have you used your filter since?

[jdircksen]

Yes, just a few times. The only way I've found to make clear syrup is to filter multiple times.
1) off the evaporator
2) finish it, then add a little DE and send as much through until it clogs
3) dump all the syrup back together, check the density, clean the filters, and send it through again

It ends up wasting some syrup when you clean the filter in between but that is better than having cloudy syrup.

[canaanmaple]

Something to add. I have one, and noticed the later season stuff Ive been bottling with that unit, does have more nitre and getting a few gallons through it (ie: filling up the bottler) without having to change the filter is getting harder.

But, I did just notice something the other day that I would say is a manufacturing flaw. The 3 tabs on the removable ring that you clamp down that holds the syrup, make contact with the flat filters and mesh filter piece BEFORE the entire outside of the ring. Making it impossible for an air-tight connection when clamped down. I plan to grind down the 3 tabs a little so the ring is the first thing to make contact and hopefully make a more air-tight seal. I will report back

[heus]

My 12" cdl filter also has a manufacturing flaw. The draw off actually runs uphill and not parallel with the top/bottom of the tank. Not a huge deal as far as performance, just a noticeable flaw from a supposedly reputable company.Come to think of it, maybe that's an intended design to keep dripping to a minimum when the valve is turned off.

[BAP]

On my 12” filter, I get crystal clear syrup on one pass, but I put quite a bit of filter aid in. This year I am using probably twice as much as I had to last year. Pre-filter plugging usually comes from not enough filter aid, than too much. I agree that there is some manufacturing oddities, like on mine, the sight gauge is not straight and it has to be tipped up a lot to get all the syrup out.