How much Vac for Zero bulk tanks?

[MASSEY JACK]

Does anyone have experience with 20 to 22" of vacuum in a Zero vac bulk tank? Will they take it or will they collapse?

[maplehound]

should be fine if it doesn't say not to vacuume it. I try to run mine between 20 and 22 but most of the time it is around 18. Although I have had it up over 22 when all the valves are off and just the tank is under vacuume. Just remember though that not all zero's are ment to be vacuumed. I have seen a couple 1000 gallon ones that say not to vacuume.

[Teuchtar]

I keep mine at 20". Even with the relief valve set at 20, I found it sneaking up towards 22" one night when the valve was getting frosty.
This year I bought a vacuum regulating valve, and I'm running it back to back with a relief valve. Don't trust those little brass bullets from McMaster.
I've read on the postings that you can suck them flat at above 20. But since I've run an accidental test on my tank, I think I know what mine could take, but I don't dare want to go there again, so I'm sticking to under 20. I think others recommended 18.
I've done Google searches, but found nothing better than whats been already recommended on the M-T.
I think the tank is probably good to 20" from what I've read, and experienced, but then you should factor in calibration of the gauge, and the risk of frosty valve.

[DS Maple]

We have 1000 gallon zero tank and last year the pressure was around 20 in hg most of the time. I got real nervous when it spiked to 25 one night after everything had frozen, but no harm done, thank goodness.

[Haynes Forest Products]

If you have a tank in mind look real close to the end of the tank in the very top of the tank. The one I turned into scrap after I started the vac pump on and screwed the regulator down. It said in very faint small lettering NON VACUUM it was a Zero tank that I got from a dairy supply................YUP they took it back:)

[MASSEY JACK]

Thanks for all the replies. I know that Maplecrest had a vac tank implode one night when it froze up before he got down to it to shut it down. The tank I am looking at was used as a dairy vac system so I know it is for vacuum. It needs a new cover gasket so I need to find one of those. It is a 550 gallon and he wants $1000. Seems like it would be well worth it because I won't need a releaser. Jack

[maplecrest]

jack, the gasket is 200 bucks. the tank is worthless with out it. a 550 will go down to 24 inches no problem. i am planning on running 24 on a zero 400. the tank that i crushed was not a vac tank. did not read the fine print. sunset tanks are not to go over 18 inches

[DS Maple]

you can pick up some adhesive weather seal stuff at a hardware store for a couple dollars that works just fine as a gasket. It needs to be replaced 2-3 times per season, but it's easy and cheap.

[Haynes Forest Products]

Just because it was a dairy vacuum tank does not mean it will take the higher HGs. MAKE SURE the one I got was from a dairy supply company and they were surprised what 24HGs could do.

[farmall h]

Ok, I was born and raised on a small dairy farm and I have never heard of a 550 gal. Zero vacuum bulk tank. Can somebody clue me in on this unit. I want one!:o

[lpakiz]

I had never heard this until a few weeks ago, but a long-time producer with a Zero tank said he needs to replace the gasket every year. Says there's something in the sap that deteriates (sp?) them. Anyone else have any problems along this line??

[maplehound]

I have made gaskets from dense foam rubber. Not sure were you can find any but look around. It is ussually black and about 1" thick. I just cut a piece big enough to cover the top hole and then cut out the inside leaving about 3 inches all around the inside perimeter. I ussually get several years out of them. I also have a couple of the origanal gaskets. The only problem I have had with them is that they get weather cracked over time, once cracked they won't seal very well.

[maplehound]

Also I suggest that whatever you use, strap the lid down with a rachet strap.

[maple flats]

Dairy doesn't run high vac, so a dairy tank may not hold that much. I'm not sure how much safety factor is built in but no dairy could go to 20", the girls would protest big time.

[Big John]

We are running a zero tank, I have 26" on it. And I hate it. The gaskets are hard to get and getting it to seal up is terrible. I am going to put a vertical releaser inside a building.

[Haynes Forest Products]

Big John Im with you when I crinkled my tank and was borrowing a tank I was wasteing alot of time releasing the vac pumping out and then resealing the covers. BUT Chuck put in a release valve and drain from the bottom fitting YEA YEA I did all that and I still hated it. Every time you would release the vac the seals would shift and the rachet straps would need to be tightened bang and slap the covers MORE duct tape :mad: Thats when I got the double Bernard:) :) :)

[KenWP]

Dairy doesn't run high vac, so a dairy tank may not hold that much. I'm not sure how much safety factor is built in but no dairy could go to 20", the girls would protest big time.

20 inchs of vac the teats would be 5 feet long in a couple of weeks.

[Big John]

I have a deep well pump in the tank pumping up 2000'. I have a wash system in it as well,but Just like you say if I want to take the cover off to scrub it with a brush It just sucks to get it to seal back up.

[MASSEY JACK]

Thanks guys, wish I had read these last few replies last night. I just went and bought the 500 gallon Zero tank today.

[DS Maple]

Don't worry, you'll be fine with it. I've never encountered any of the problems mentioned here, just a gasket replacement every once in while. Like I mentioned before, this takes about a minute and $5 down at the local hardware store. No ordering special parts or anything. As far as pumping is concerned just hook your pump up to the drain on the tank, start the pump and then open the valve. My little cheapy pacer pump will suck against vacuum no problem, but if you open the valve before starting the pump, the negative pressure in the tank will suck the prime right out of it.

[markct]

wow i thought i would have to release the vac to pump it out, i had no idea the pumps could pull the sap out overcoming the vac.

[Haynes Forest Products]

Did DS mention it take 3 hrs to drain the tank:lol:

[DS Maple]

I can pump about 40-50 gpm out of the tank when it is under vacuum. Put an extra valve on the top somewhere so you can open it if necessary to speed up the pumping process, but you should never have to release all the vacuum on the entire tank. A good pump will overcome 20" of vac no problem.

[maplecrest]

15 years ago i used a sunset 500 gallon vac tank as a releaser. had a float switch in it. the pump was a dairy recever jar pump on the drain port. the pump pumped the sap up to my sugar house 300 feet away against the vac and worked great.

[mmccallum]

ANyone know where I might be able to get a copy, even photocopy, of a Zero wv-800 (800g) milk tank owner's manual?
I have the tank, but not even basic instructions on operation.

[Joust7.1]

I can pump about 40-50 gpm out of the tank when it is under vacuum. Put an extra valve on the top somewhere so you can open it if necessary to speed up the pumping process, but you should never have to release all the vacuum on the entire tank. A good pump will overcome 20" of vac no problem.

This sounds like my set up but I haven't been able to empty the tank under vac yet. I have the original tank washer pump to pump with and I mount it to the drain outlet with a very short piece of hose. It seems to be a great little pump but I'm not sure it can overcome the vac. How do you plumb it to get it to prime? As soon as I open the drain valve it sucks air in like crazy. I haven't tried starting the pump first as I am worried about destroying the pump. Should I just give this a try or has anyone else tried this already with or without success. This is my best/only transfer pump right now and I don't want to risk ruining it but evacuating the tank under vac would be a huge time saver.

[wiam]

Skdj
This sounds like my set up but I haven't been able to empty the tank under vac yet. I have the original tank washer pump to pump with and I mount it to the drain outlet with a very short piece of hose. It seems to be a great little pump but I'm not sure it can overcome the vac. How do you plumb it to get it to prime? As soon as I open the drain valve it sucks air in like crazy. I haven't tried starting the pump first as I am worried about destroying the pump. Should I just give this a try or has anyone else tried this already with or without success. This is my best/only transfer pump right now and I don't want to risk ruining it but evacuating the tank under vac would be a huge time saver.

Put a check valve on the outlet of pump. Between pump and check valve t in a small line to top of tank. Have swing check valve in small line so it closes when pumping.