Liquid ring pump and regulator

[doocat]

For anyone running a liquid ring pump now.

Should you install a regulator on the system or will the pump max at 27-29 inches? Pros or cons of the using a regulator?

Are there any issues with the amount of vacuum and pump heating up?

Oh yeah it is a oil cooled liquid ring...

Thanks, Craig

[Mark]

I have a single stage sihi with a regulator on it but I have the weight on it adjusted so it will not open. I was on the Maine tour and overheard a couple big producers laughing about someones regulator and how it is not needed and go for as much vacuum as you can. If it is a single stage you will not get as high as they are rated.
I am going to a 2 stage this year and I am even wondering if one is needed on it.

[Amber Gold]

I'm not planning on putting a regulator in...I thought the idea was to pull as much vacuum as you can.

I did get mine hooked up yesterday. It took a bit longer that I was expecting with the VFD and programming that. I just had the pump hooked to my releaser and was having problems with cavitation. I tinkered with it for a bit and was able to get it to 22". The directions said a little air is needed to keep the pump from cavitating, which I found surprising. This weekend I'm going to hook one of my mainlines to it and see if I can get it up to its rated 25" without it cavitating. I've noticed that the LR aren't plug and play like the dairy pumps are...it seems there's a bit more to them.

[sapman]

I have wondered the same thing. I was told that if the pump runs for long periods without pulling anything, e.g. everything is frozen, that it could do damage. Don't know if that's true or not.

Tim

[Mark]

It would not hurt a Sihi, the cooling water is circulating all the time. The highest load is in free air and when there is no airflow the load on the motor drops off.

[Amber Gold]

What do you mean by "free air"? Sometimes when running at max rpm, the amp load would drop from 6.5 to 5.6+/- and it sounded like the pump speed increased...kind of like it was no longer under a load. It didn't get any louder like it was cavitating, but it sounded like it was freewheeling (I guess). When this happened, I turned the rpm's back down until it came back under a load. I wasn't sure if this was bad so I didn't leave it there. The releaser's outside so I didn't check the vac. levels.

Was the pump actually achieving max vacuum, so there was no air to put the motor under a load? Is this what I actually want to happen? This is my first LR pump so this is a compete learning experiance.

[Mark]

Free air would be like not hooking it up to your extractor tank or having a ton of leaks. I can tell how tight my system is when I hear a ticking from the swing check valve on the vacuum pump and also the motor amps drops off. If I have a lot of leaks the check valve is open and never closes to make that sound.

[Amber Gold]

So when my amps dropped and the pump spun faster, that actually meant it had created high vac. levels, so it wasn't sucking in much air, so the load on the motor was reduced (dropping the amps), and less air was being sucked in (allowing the pump to spin faster). This is what I actually want to happen? It makes sense if it is. I'm pretty sure when this happened, the pump was running nice and smooth.

[Mark]

Yes that is what you want. If you let more air in it would put more of a load on the motor and drag the rpm's down. A motor acts like a generator in the opposite direction which limits in current and when you put more of a load on it and slow it down more current can come in to get back up to equilibrium. I can't explain it very good but it is called Back EMF or back electromotive force.
That is why motor starting current is so high. If you use a mechanical releaser the motor works harder every time it switches chambers.

[Amber Gold]

Great. So I guess I'm in better shape than I thought.

Thanks

[maplwrks]

Josh---Is there a reason for putting the frquency drive on your vacuum pump? I've never heard of someone putting a drive on a pump that small.

[doocat]

Does anyone have any experience with oil cooled liquid ring pumps? We hooked ours up and filled the reclaimer with oil then started pump. It took a while to get up to 25" with just 10' of pipe plugged. I then check the pump and it seemed pretty hot. I was wondering if there was a need to bleed the oil or some other secret with the radiator. Sure don't want to hurt he pump this close to season.

Thanks, Craig

[maplwrks]

Craig---I assume you have an Atlantic Fluidics pump? ALL L/R pumps need liquid in the pump head to create vacuum. On mine, I need to let the oil fill the radiator and start to fill the pump before it will create any vacuum at all. It has a flow restrictor inline to the radiator, so it takes a while for the oil to make it's way around. once you start pulling good vacuum, recheck the oil in the reclaimer, you may need to add more.

[doocat]

Yes it is Atlantic Fluidics. I did notice that after we were playing with it the oil was down. We will fill it in the moring and test it again.

[Amber Gold]

Mike, the pump came with a 3 phase motor so I needed to convert phases, which is what the VFD is for. I'm also getting the added benefit of it giving me amperage readings so I can more easily adjust the water flow.

I spoke to Tuthill about using oil and they recommended a 5W or 10W oil. If you're using too thick of an oil it probably won't work properly.

[maplwrks]

Got it!!! I haven't seen an AF pump w/ 3 phase--once you get things real tight, it'll save you $$$$ also!

I've used vacuum pump oil right off the shelf at TSC for my AF pump, with no problems!!

[maplwrks]

On another note--make sure you run a moisture trap between your pump and releaser. I've had it suck a little sap into the pump and it layers up in the reclaimer, soon you're circulating sap around the radiator and running high temps, and little vacuum.

[Brian Ryther]

On a similar note, Mike what are you using for a moisture trap?

[maplwrks]

I got one from Leader---Lapierre makes a good one also.

[Amber Gold]

I hadn't considered a moisture trap...wasn't going to worry about it with me using straight water as a cooling liquid.

I'm using a 1" pipe from the releaser to the pump. I already have a moisture trap with 3/4" fittings. With it being so close to the pump will it offer much of a restriction or should I get a moisture trap w/ 1" fittings? If I use a moisture trap, can I use the vacuum regulator from my dairy pump to prevent the pump from overheating if the moisture traps sucks in sap?

My dairy pump has a 3/4 hp motor and draws 5.5 amps. My LR pump has a 1.5 hp motor but draws 4.6 amps...I was surprised to see that. My electric bill saw a significant spike last maple season.

[maplwrks]

Josh---It's more important to have a moisture trap on an oil cooled L/R and a vane pump. If you are running a water cooled pump, it isn't as necessary.

[Amber Gold]

Good...one less thing to have issues with. If I find my stock tank overflowing I guess I know why...

[bigtreemaple]

How much water volume do you think it takes to keep the L10 AF pump cool enough to operate efficiently? I was thinking of using an old syrup barrell for my cooling tank.

[Amber Gold]

The manufacturer said the more the better, but if you have a cooling system then 20-30 gallons is fine.

[Amber Gold]

I hooked my lines to the releaser today and fired the pump up again today. Now that I knew what to expect everything went well. Pump ran great, nice and quiet for a couple of hours. I was surprised how quiet the pump got once things had settled down. The motor's amp use was right where it was supposed to be. I shut the water down to at trickle (still need to install the gate valve for better adjustability but it worked) and I was pulling 24". I was expecting 25"+, but wasn't getting there even with the lines shut off and just pulling vac. on the releaser. I have one of the cheap Aschroft vac. gauges on there so it may not be accurate. I have a good liquid filled gauge that I forgot about until after I drained the tank. I'll get it running again later this week and see if it does any better with the new gauge. The water is <60F as it came from my well and didn't run long enough to heat up.

One thing that concerns me is when I manually dumped the releaser and the pump discharge water would come to a trickle or stop and the pump would make a screeching type noise until good vac. levels were re-attained. I'm not inside the SH so I'm not sure if it's noticeable in there. It was quite loud and I'm guessing it sounded like the pump was running dry. Is this typical? Is the pump sucking in too much air for the amount of water available in the intake pipe so the water:air ratio is off? Don't know...just guessing.

Thanks for your help in this thread.

[PATheron]

Josh- I havent been following everything your doing with your pump but that shreaking noise is a bad thing. Sounds to me like not enough water going to the pump or something. Should not do that I dont think. Ive had mine shreak when it wasnt getting water, like the line shut off or something and I turned it right back off but you better see whats going on. Maybe you can call the pump manufacturer and tell them how you have it hooked up and see what they can tell you to help you out. Theron

[Amber Gold]

From what I can tell it's getting enough water when it's pulling vac...nice and quiet. The manufacturer said to adjust the water flow to get the amp readings to match the motor's amp rating. For example, the motor is rated for 4.6 amps at 230V, so I reduced the water until the amp reading on the VFD was 4.6. It's only when the releaser dumps and it's getting an influx of air that it makes the shreaking noise. I've been in contact with the manufacturer figuring out how to set everything up. An email to them about this is the next thing on my list.

Aside from that, I like the pump and I can't wait to pull high vac. this year.

Thanks Theron.

[Squaredeal]

Josh, I have a A130 which granted is a bigger pump, but I discovered that in a short period of time that it will heat up 200 gallons of cooling water when the air temps start to rise. With the rise in cooling water temp, there is a resultant decrease in vacuum. I have solved this by running a 5/16 line from my well teed into the cooling water supply where it enters the pump. You may not need this, but I would suggest being ready in case you do.
I also have a valve that I can use to adjust the rate of water supply I don't have a vfd, so I adjust by 'ear' -works quite well.
As for the screech x2 on it being a bad thing. Do you have a check valve between the releaser and the pump? Is it possible that it is in backwards?
Good luck, and pm me if you want/need help.
Ray

[gmcooper]

Josh from reading this thread and that last few I think you may not be getting enough water flow through the pump. Sounds like you might be getting enough with the system closed but when the releaser dumps the pump needs to pull a bunch of air thru and there is not enough liquid flow. I have a 35 cfm from Harris and the cooling water valve stays wide open and I can run up to 26" (still had a few leaks). With 850 taps I can get up to 22" in less than 2 minutes. Mine does squeal for a second or two when I start the pump.
Have to give you a bunch of credit as most would be testing the system the day sap starts running.
Good Luck

[Amber Gold]

Does the check valve serve another purpose besides making sure the pump doesn't spin backwards during shutdown? I didn't install one because the one's I was finding were spring operated. I just found a swing check valve, which I'm more comfortable with not sticking so I will install one of those.

I started the pump with the water valve wide open. The discharge water shoots out and comes in spurts and I was pulling about 15". Also the load on the motor was about 6 amps. I reduced the water flow, the vac. level rises to 20"+, the amp readings drop below 5, and the discharge water is pretty smooth and the pump quiets down and runs smooth. This is just what I've noticed.

Running straight water, do I need to worry about the pump or water freezing if I leave the pump running 24/7 during the season? I didn't want to run a glycol/water mix or oil because of the expense. I have a stock tank heater if need be which will keep the water at 40F. I was running it for 2 hrs yesterday in the 20's with a good wind and it seemed to be fine. I'm going to run it all day this weekend and see what the water temp does.

Thanks GM. I'm relying on the pump for a sap ladder to get everything back to the SH, so I want to make sure it's fully operational before the season starts.

SquareDeal-It's only 100 gal of water so even if I need to drain and fill every day it's not too big of a deal. The well is across the yard so running a feed from it wouldn't be much of an option. I'm going to put a fan across the radiator which should keep things cool.

[Amber Gold]

Pump's been running 24/7 since Saturday morning and it's still holding over 22" at the releaser and still making the noise when the releaser dumps. I'll take it apart after the season. There was a rattling...sounded like a loose bearing in the pump (which I don't think there is one), but that went away and aside from dumping the pump is pretty quiet. It works so I'm not going to worry about it. It will be going outside though next year to make the SH a bit quieter. I am disappointed I'm not get 25"+ out of it , but I'll worry about that for next year.

Biggest problem I'm having now is keeping water temps low...averaging 50-55F. Pump curve is rated at 60F, so I'm keeping below that. I was hoping to keep it in the 30's to low 40's.

[caseyssugarshack93]

Ag 22 is still pretty good, if you got a good deal on the pump and it gets you though the season, i could see being a little mad if you paid alot for the pump and didnt end up getting the inches you wanted, I take it you probably got a good deal on the pump though,

[Amber Gold]

I got a pretty good deal...$270 for a $2000 pump...so you're right. I figure if I make it through the season and the pump's trashed it was an operating expense for the year. I could do one of these a year and it'd pay for itself.

More disappointed than anything...just trying to be like Theron and get 27".

[Amber Gold]

I went to Chip's over the weekend and he showed me his pump...smaller version of mine. His sounds just like mine which is good. Mine just makes the loud noise when the releaser dumps, but it's not that noticeable inside with the pump, just at the exhaust. I noticed it does it as it's ramping up and creating vacuum...maybe it's just the noise it makes when it's sucking in large quantities of air??

I found out the cooling fan works much better on high. I found out tonight the fan was on low speed and I could only keep the temp's around 55F. I turned it on high and in an hour they were down to 50F...another hour and 47F. Much better numbers.

I also found out the valves on the gauges needs to be opened up periodically. I opened the valve up in the house in a warm environment and then brought them outside connected...gauges never did better than 24". Tonight on a whim I opened the valve and the gauge shot right up to 27". All's good.

I also found out that an hour after shutting off my 3 mainlines they still had 10" in them, so I'd say they're fairly tight. Hopefully saps flowing good enough I can check for leaks tomorrow morning.