Vacuum Pump Voltage, 120 or 240V?

Hash and Stuff Extraction
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Got an edwards 18 off eBay and plan to use it as backing pump for an oil diffusion pump (edwards 50/60) for the vacuum system in 6” wiper. It came in wired fir 208V but the panel says it can take anywhere between 110V to 240V. There’s no 208V line running to where this skid is going to live so the plan was to rewrite the motor to 120V and call it a day.

Is there any reason to not do this from a performance standpoint? Using as a primary vacuum pump, I would guess the displacement of the motor would be lower, but I’d be curious by how much. I figure since this is a backing pump it’s going to matter less, but now I’m not sure.

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Less amperage usually so it’ll be nicer on your electrical system. Not sure about the actual performance of it but if switchable ballasts on lights are any indication since grows flop from 120/240 depending on the scale they work just the same.

Watts / Volts = Amps

This is different for three phase though of course

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That’s a good point, though it’s probably cheaper for me to buy and fix a new pump than running a new 208 line

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First off you need to be slightly informed.

There is a difference between,

200v
208v
220-240v
110/220 or also refered to as 120/240 switchable.

A 208 outlet cannot be used for any of the switchable or 220-240 style pumps.

A 110/220-120/240 style pump has almost zero difference in performance except a 220-240 configuration gets about 2% deeper vacuum. A 220-240 pump will use half the amps a 110-120 will.

When it comes to vacuum pumps if you can run 220-240 then you should. The pump runs cooler and generated a healthier vacuum. A 110-120 configured pump runs twice the amps and more heat, leaning your amp availability in your room depleted(if you are purposely ordering 220 devices in a 110 configuration becusee you are lazy to swap breakers)…at 220 it has been said pumps run slightly deeper, but just slightly. They do however perform better overall.

If you have argo or commercial 200-208 or anything under 60hz you need to order a specialty pump set at 200-208. If you take a 220-240 or even a 110 pump and use a 208 like or split it to a 104v off the tap then you will fry your pumps and electronics.

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Almost any outlet can be switched from 110-220 or from split voltages to a 208 a a example. Get a double gang breaker and swap your breaker, and take the neutral off the neutral bar and put it on the second two of the breaker. It will directly convert the already ran wiring to 220-240. The issue is if you have 208 you need to install a transformer and fix your power and get rid of the 208. You’ll end up burning up everything in your lab.

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Also, you need two pumps. One that is installed on the diffusion pump only and never sees anything but diffusion pump vapors. And you need a similar second one to pump the system down and get to vacuum as the solventated vapors will shut your diffusion pump down in use.

A Edwards 50/60 won’t work on a 6" wiper properly. You’ll launch the silicone oil out and I to your Edwards in about ten minutes or less. Edwards 50/60 style air cooled pumps only can diffuse empty analytical chambers basically. They don’t actually work with in flow diffusion work. The reason why they add them on wipers is becusee the salesmen want to sell you a second round or proper pumps and tell you “we just wanted to save you money on the first purchase” and then you realize diffusion requires a bigger water cooled pump, a medium sized chiller, a couple expensive sensors, and a better backing pump.

A Edwards 18 is undersized for a 6" wiper. And the diffusion pump you have really won’t work at all. A great way to find out for yourself is get a couple thousand dollar sensor designed to read diffusion pumps. Dead head the pump for a few hours and notice the reading. Then open it up to a short path or wiper and watch the sensor above the diffusion pump go into standard 1-1000 unit measurements and not into the ten scales below 1 micron. Who ever sold you a 50/60 on a wiper didn’t know dick about vacuum and was trying to sell you junk they had laying around.

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Good to know on the 208 vs 220, I’ll look at the motor schematic to see what it’s actually able to do. Amperage will cause more heat for sure but I’m glad learned that there’s only a 2% performance increase so thank you.

I will say, don’t worry about someone ripping me off, I’m designing the system myself so the only one who got me into this mess is me; and while Im not an expert in high vacuum applications, I do know a bit more than dick :wink:.

’m not sure I agree with you that you need 2 separate pumps (one for backing, one for rough vacuum) if a couple of valves are there and the material is prepped correctly. My plan was to use the oil pump to achieve a rough vacuum, turn in the diffusion pump then close the cold trap to rough valve and open the inlet for the diffusion pump and turn that on. Once the diffusion pump was up to temp, distillation would begin and if there was a need to break vacuum, isolating the diffusion pump and shutting it off would be a safe way to do that. Additionally, I planned on doing a volatile strip in my short path since it only takes an hour to purge a large batch and it would protect the pumps on the wiper. I do see your point on the 50/60 being a wimpy pump but the listed displacement seems fine for this apparatus, especially since I don’t intend to get below 0.1 micron.

I’m also surprised to hear an edwards 18 is undersized for a wiper, 15 cfm displacement seems adequate for most stills this size. This is also going to be run in batch mode so the feed is going to get degassed on startup, which made displacement less of a concern to me

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That 2 percent is not something to balk about. It’s worth it. The extra heat that’s being generated are the coils in the motor pump burning out. So it’s absolutely a bad thing. Well if your going to buy pumps from people they should be verifying the use to ensure it’s going to be applicable.

You do need two different pumps if you expect your diffusion to work correctly. Currently you have the wrong diffusion specd. The concept is that one pump only ever is exposed to diffusion rates and this keeping your diffusion oil clean. When you use valves to go in and out the smallest cfm spike with splash your silicone oil out and rocket into your backing pump.

I’m sorry to break it to you but your plan isn’t sound or correct technically. You don’t opperate diffusion pumps like that. You need to let the diffusion pump run for a extended amount of time with its own backing pump to achieve diffusion rates. Then it is engaged via a valve when the system is ready to accept the diffusion rate.

Volatile strips are for roughing pumps so to speak, but there are other components that will get sucked into diffusion pump other than volatiles during your main wiper run.

The 50/60 is not specd to run a wiper like that. It’s not even remotely correct. It was originally sold by other wiper companies as a sales scam to get you to buy a real diffusion setup.

Something to remember. If your diffusion pump is running a couple of steps below at the pump, the wiper will never go below 1-5 microns becusee distillation rates will lower the bell curve of the distillation temps but never affect the system itself. Only the pump. Also I suggest you invest is a diffusion setup sensor system. Otherwise you’ll never even know f your diffusion is working or not. 98% of the time the Edwards 50/60 style pumps on wipers don’t work. Reason being people don’t invest in a sensor to tell them that jey splashed the oil out and the backing pump is now suffering.

The problem is a diffusion pump like a 50/60 only requires a Edwards 18 on a small analytical system or a vacuum oven where it’s required. Once you let the cfm loose from the wiper it will over load the diffusion and the backing pump can’t handle it. Your e18 only works when there’s no load in the 50/60.

Most people use e2m28 pumps on diffusions, larger ones for your task. Because they can eject and evacuate the extreme cfm the diffusion kicks off. For a wiper of your wise you need a water cooled diffusion pump and something around 400-600liters per second. That requires a much larger backing pump for sustain diffusion rates.

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2% of what is a good question, 2% lower ultimate pressure? Because going from 100 to 98 micron seems unimportant when the goal in many vacuum applications is to get lower by orders of magnitude.

I’m not sure I trust eBay sellers to provide such a service lol.

I also have seen a roughing pump double as a backing pump on multiple systems. Beaker and wrench has a system like this as well as Prescott systems (renowned for their low vacuum levels).

I also fail to see why these pumps (at the very least the edwards 18) is inadequate, beaker and wrenches has a 35cfm displacement (unsure make and model) but the Prescott is only 8.8 cfm (edwards 15ic). I assume this is because of internal volume but that’s a broad scale.

Are you able to substantiate why this is the case? Internal volume seems like the only dimension to me. There will also be a cold trap on this so not sure if that’s the case.

There will also be an external condenser at -60 to act as a cold trap.

A lower more sensitive sensor is necessary for this application.

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Listen up tiger, I’m not really trying to argue with you. So I’ll lay some deets ooought…

It’s more than 2%. I was just trying to create a tangible number. But for arguments sake that ,2% we are talking about is substantial. A 220-240 pump rated at 5-10 microns will opperate around 500 microns if used on 208 in some cases even worse. The lowered voltage doesn’t just affect the ultimate vacuum it also slows the pump down, you nearly kill half the volume of molecular flow in the cubic feet per minute range since the pumps mechanics are literally slower and the moving parts cannot capture molecules in motion as well. While under vacuum you are essentially capturing molecules in motion. If you reduce the effect your distillation will run slower.

There are absolutely no legitimate diffusion packages that utilize low vacuum depths as advertised. Looking at brochures for sales purposes doesn’t solidify your ideas, in fact so many wiper companies used the same sales configuration to try and boost sales. When users get them they realize using a single Edwards 28 outperformed the e50/60 and Edwards multivalved single small pump options. You are wasting your breath and effort and money. Every lab I’ve worked at that had a wiper apparently got rid of the small single pump - air cooled diffusions and replaced them with professionally specd setups. They also completely change how your wiper performa and behaves.

I’m telling you, a Edwards 30 style pump will take a fat steamy oily dump on your attempt to use a e50/60 with a e2m18 pump. The reason why you see those sales options on these wipers is because their markup on pumping assemblies is about 5x the actual cost. They know if they charge you 100+ thousand dollars for 15-25k in appropriate bad ass brand new hardware it might kill the sale.

Also Edwards technically stopped making the e50/60, or the European source company stopped. So only rebuilt or factory remains are available and they are very cheap, also a reason to have higher margins on selling a unsuspecting customer a e50/60 combo unit.

If you plan to use diffusion go at least with a ip-80 style -80c cooling setup. The -60 single stage secondary stage immersion chillers aren’t strong or capable enough to sustain cold temps on your trap while the diffusion is engaged. It will still pull hot gas past the trap at -60.

May I ask, who coached you into this product purchase. Where did you learn or were told to do this nightmare of a configuration???

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I’m not trying to argue either. Calling an adult ‘tiger’ doesn’t necessarily diffuse things but perhaps I sound curt, apologies if I do, I speak rather plainly.

I should clarify that when asking you to substantiate, I meant an explanation other than ‘the pump isn’t spec’d for that’. Why isn’t it spec’d for that? I’m genuinely curious about the thought process as well as the engineering of this. Do you have a system that you think is adequate/what size do you think is adequate for a 6” wiper and why?

I’m confused why 1 to 500 micron isn’t substantial because that is to me, and why your tone changed from near zero to substantial (hence my confusion at the 2% figure). Initially I see your point when you describe lower vacuum level due to faster rotation, but that seems erroneous to me because an ac motor is going to spin faster with frequency whereas the voltage would cause the rotation to have more torque. There are more nuances here but are those assumptions incorrect? Is torque important in a rotary vane pump? I would assume not

As far as sizing goes, my design process was pretty low tech, find good system, ensure specs are proportional/close enough, I specifically used prescott as a model for a well designed system because I’ve heard nothing but glowing reviews.

As far as -60C not being cold enough, that seems like it’s dependent on the volatility of the initial feed stock. Material purged to 100C at 100 micron beforehand seems adequate, this depends on the ultimate vacuum of the diffusion, but I suppose that depends on the vapor pressure of our most volatile compound at -60​:crazy_face::rofl:.

I wasn’t coached into this by anyone, it’s a system I designed and am assembling myself because I cannot abide the 8 hour residence time my crude/distillate has in my still, the degradation from that alone made this a necessity from a business standpoint. I found a good deal on an ss wiper body and spec’d the supplemental equipment myself; I run a small family business and sometimes we have to make do. The pumps were purchased on eBay and I refurbished/rebuilt them myself as well. Don’t feel the need to feel indignant on my behalf. No one talked me into this; I’m a big tiger and can deal with the consequences🐯.

The decision of a diffusion pump arose because there are plenty of cheap ones and worst case I’d have it around for future use if needed. I’m out $500 if it doesn’t work, but likely case it’ll lower my pressure and thus bp, worst case I can build that magnetron sputterer I’ve been wanting to make for a while. My only goal of this project is to cut residence time (it’s literally costing me at least $500 a week in degradation) and the edwards 18 will do that. I’m sick of short paths, they do the job but so inferior at scale imo.

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Short paths don’t have degradation if they are configured correctly. Extended residency times from poor setups are what cause issues. Properly setup and configured short paths don’t just ruin your material. It may have something to do with your configuration.
Wipers take more of a “mixed body” than a short path does by quite a bit. Degradation is being caused by something else, maybe your pump assembly. Maybe you are running a undersized pump.

What do you think happens when you install a diffusion pump on a short path. It completely transforms it. Anyways, if you want to waste you time with a e50-60 go right ahead. I’m just trying to help you out famalam.

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Do you have a short path you would recommend? I’m getting below 100 micron every run and collect my main fraction with the mantle at 195C, which is about as good as I can manage without rebuilding my pump every run.

While there is a more mixed body, I think the market has showed that it isn’t a disqualifying factor. Taking residence time from several hours to a few minutes shows a fundamental difference, short paths just won’t beat that even at moderate scales, and distillation towers will win out at large scales.

I’m not sure I agree with transforms it, it lowers the pressure and thus temperatures.

I’ll be happy to waste my time on it if I can learn something since that’s not a waste. I appreciate the discussion, but I’m also not going to take your word as gospel. I’m still unsure how you came to your conclusions so I can’t really take you at your word, especially with a week old profile. Cheers fam

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You have to rebuild pumps on every run?
What does running temps have to do with pumps needing to be rebuilt? Residence time doesn’t really matter. THC and most cannabinoids don’t degrade just from sitting hot under vacuum. The mixed body issue is still a contention with buyers because they want to pay basically for the mg content of potency. The higher potency, higher stability, and proper colors are always preferred. When you take wipers with mixed body or lower potency, you’ll notice you’ll always get that “general thick gel” out of the wiper and most cases even some foot smell with it. That weird fragrant dirty feet smell is common. This is very normal with wipers. Most professional outfits I’ve worked at actually use the wipers to do a initial strip or first pass, then load the result into a spd. The output results are better on a spd. As spd may not be useful for turning over 300 gallons a day of crude it still has its benefits and performance curves. The fact that short paths have a collectively higher vapor pressure, if you run them like wipers with discharge pumps and diffusion pumps they behave very different. In a wiper you have fractionally less available vapor pressure. Because of this you generally take mixed fraction. Short paths generate a very high pressure under vacuum and that’s why you can remove heads and unwanted fractions a bit easier. Then when a main body develops it comes very fast and hard and does stop untill that vapor pressure is reduced. They will easily exceed wipers. And the best part is generally per pesos spent the short path will still be faster if setup right. If you are using some old school setup that’s basically not setup right maybe that’s why you are experiencing issues. Wipers have their use, not going to doubt that. But if you plan on using a Edwards air cooled diffusion on a wiper you’re going to have a bad day, and especially I’m assuming you don’t have a proper sensor that will show you that it’s not working correctly. One serious issue is the volume in the air cooling pump is insufficient to handle a loaded stream of vapors. And the air cooling doesn’t have the ability to cool the pump down while it’s operating and diffusing vapors in motion. The 50/60 was designed and supplied to manufacturers who used them on small chambers or analytical devices that required high vacuum to be used. It is absolutely not a short path pump. Every 50/60 supplied with a wiper “to make a quick sale” has been stripped from those units and surplus sold off. Nobody uses them for a reason. They don’t work well at all. Companies used to get them refurbished very cheap and add a giant markup on wipers but they know you’ll be coming back for a new pump within a week or two of hating your life. Wiper companies knew they would have a hard time with higher markups selling people vacuum arrays that actually worked right.

Brother, I can assure you if you get a decent diffusion pump and install a correct array of roughing and backing pumps on a short path it will transform the short path immediately into a monster. You will also enjoy and not hate your life if you learn about how diffusion pumps are scaled, setup, and opperate first before using them.

Someone told me a long time ago “you don’t need to experiment and learn from your mistakes, you just need to learn from others and succeed without mistakes, you aren’t the first one to try this”. Learning from wasting 500 bucks and energy to do something that’s known not to be right just to “learn something” new is a very bad approach and waste of effort.

Me and you don’t need to figure things out. Smarter people than us figured it out a long time ago for us.

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There is also a lot to be said for “run what you brung”…margins aren’t what they used to be.

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I absolutely agree with you. If I had a choice I would bring other things to run :-(. I’ve played with vtas at labs I’ve worked at and even some medium grade glass wipers and some larger stainless wipers. Last place had a old ychem that was always down. I remember seeing the old 50/60 units in shelves and always asked why they don’t use them. Learned the hard way myself as well …

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I saw a 300l stainless SPD setup being fabricated a few years back. Never did learn how it faired…

The flask and mantle were a single unit, but otherwise looked almost identical to their smaller glass counterparts

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I get my lowest vacuums off a fresh rebuild. After that, it steps up a few micron to where it stays (ultimate vacuum sub 1 micron to 10 after 1st run with oil change :person_shrugging:). I purge well and use liquid nitrogen in my cold trap so my pump is always clean.

I disagree that cannabinoids don’t degrade under vacuum. Thermal isomerization can occur at quite low temps, so several hours at 195C is definitely enough for autodegradation. It may also not show up on an HPLC as there are many species that aren’t tested. As for the foot smell, I’ve had seen some stanky stuff for sure, but it depends on purpose, oil that tasted bad in edibles was fine in vapes and I know the condenser wasn’t run particularly hot, I know of near perfect distillate out of a wiper.

If I had all the money in the world I would, though I’m more of a ‘backups for backups’ than a ‘size queen’ when it comes to supporting equipment, I know the rule of thumb is 4cfm/L but I think that breaks down at larger volumes.

I’m sure I’ve got a shitty day ahead of me, but I learn by doing and as someone who has spent a lot of their life studying and in academics, it is much more time efficient to learn by doing, I assure you. Theory will only take you so far. Also, while smarter people may have figured this out, they were not perfect; assumptions must be tested because smart people can be wrong. If you can’t tell, I don’t like appeals to authority.

I believe you and I see the world in very different ways; I don’t see us coming to much of a consensus on anything though, which is fine. Imma give it a try anyway. I’ll leave updates too (probably in another thread) so you can relish in my failures :wink: .

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