Sciencemadness Discussion Board - DIY vacuum filter any ideas ?

DIY vacuum filter any ideas ?

LD5050 - 23-2-2017 at 12:36

Ok so I bought a new vacuum pump from harbor freight for vacuum distillation and vacuum filtering and such and I want to set up some type of filter system to keep all the solvents and other chems from destroying the vacuum. What are some methods that you guys use for your pumps? Is there a cheap filter system I can buy? Is there some kind of DIY filter system I can build, maybe out of PVC and some kind of desiccant? Or is it sufficiant to set up some kind of simple water trap system out of a flask and some tubing? I would like to know what people here use for there vacuums and maybe shoot some ideas back and forth about building some kind of filter.

TheNerdyFarmer - 24-2-2017 at 11:17

Luckily you are not the first! What you need is what is known as a vacuum cold trap. This is quite a pricey piece of glass so if you are willing to invest some money in it by all means do so. I mostly use an aspirator vacuum pump so I don't have this issue. But I'm sure you can design and make one if you look at a bunch of models. Many people use liquid nitrogen as coolant for this but you could probably get away with some dry ice maybe. In the U.S. its only like $2 a pound for dry ice so it should not be an issue.

Lillica - 24-2-2017 at 18:14

The Harbor Freight vacuums are pretty nice. You can use them without a cold trap but it's pretty much a guarantee that the vacuum oil will accumulate solvents and you'll have to drain it and add more oil. Normal solvents don't seem to cause any damage to the vacuum. The worst I've had happen is the oil will overflow into the hose... which recently spat dirty oil into a vacuum distillation I was doing. It was my fault for not checking the oil level prior to using it.

Ever since I've had my Harbor Freight vacuum, I've had to drain and replace the oil approximately every 1-2 weeks because volatile solvents accumulate fast. Expect to do this even more often if you are doing a long(10min+) filtration such as with an easy clogging filter. Changing the oil on these pumps is fairly easy and only takes 10 minutes, just drain it from the bottom drain port, and add more through the top.

I've never used a cold trap with my vacuum... though a word of warning....I did mess up one of my vacuums by accidentally having it pull through some bromine, which rusted the inside and basically screwed the motor up and made it stop working within a week.

Fortunately, Harbor Freight had a 90 day return/exchange policy. When I took my pump back to exchange it for a new one, the guy suggested I buy the cheap (~$15) 1 year warranty. He said I can return it any time during that year if it breaks, and even re-purchase the warranty each time I swap it out. He even suggested that I swap it out at the end of the year even if it's not broken... so it's like getting a free vacuum pump each year... well, at the cost of another the 1-year warranty.

JJay - 24-2-2017 at 18:30

zts16 built some traps to protect his vacuum pump and posted pictures a while back... I think they are on the everday chemistry thread.

Solvents won't destroy your pump as long as you replace the oil frequently enough that it doesn't get excessively diluted. It's the corrosives you need to worry about.... I've pulled bromine vapors through pumps no problem on a few occasions, but it's not good for the pump... you can reduce the amount of halogens going through the pump by using a trap filled with thiosulfate solution. A cold trap might help but needs to be really cold for chlorine.

I personally think that waranties sold by shady sales personnel are a ripoff and a waste of money, but they might provide peace of mind for people who don't plan on immediately violating them by, for example, using a cryogenic pump for lab use.

[Edited on 25-2-2017 by JJay]

Lillica - 24-2-2017 at 18:54

Quote: Originally posted by JJay

I personally think that waranties sold by shady sales personnel are a ripoff and a waste of money, but they might provide peace of mind for people who don't plan on immediately violating them by, for example, using a cryogenic pump for lab use.

[Edited on 25-2-2017 by JJay]

It is true that most consumers of products will never use their warranty. Companies wouldn't sell them for so cheaply if it wasn't profitable for them to do so.

$15 extra to replace a $115 item at anytime during the year is a pretty good deal. Without a doubt necessary for any hobby chemists, as most hobby chemists are not going to have a cold-enough trap setup every time they use their vacuum. With all kinds of possible different reagents going through that vacuum, there's no telling what could break it.

JJay - 24-2-2017 at 18:56

I don't think you understand what I just posted; you can't use a cryogenic pump for lab use without violating the warranty. It's dishonest.

Harbor Freight's 90 day warranty for their cryogenic pumps states that they will replace them only due to manufacturer's defects. By stating that you destroyed your pump with bromine vapors and returned it, you are admitting to having committed fraud.

This is not an issue where amateur chemists require a warranty, etc. - you have no idea what you're talking about and are giving unscrupulous advice based on questionable experience.

I should add that I don't believe that you are actually a chemist and think you actually completely fabricated the story about destroying your pump with bromine vapors, but I have no proof of that. I have proof that you admitted to scamming Harbor Freight. That sort of thing gives amateur chemists a bad name. While I don't think you are truly a disgrace to the scientific community, I think you are a disgrace to your own particular brand of poseur.

[Edited on 25-2-2017 by JJay]

Lillica - 24-2-2017 at 19:40

Erm... JJay first of all, I told the Harbor Freight guy exactly what I was doing, he didn't have any objection to it, and on the contrary he was quite fascinated. I told him it broke after a few weeks of me using it and told him that it was being used in a laboratory. He never told me any restrictions about the vacuum warranty or any restricted uses of it.

I was only posting my honest experience which I didn't think was improper or illegal in the slightest, and yet you are now calling me a scammer and even going as far to say I am not a chemist. That's just funny, but I think my collection of some 200 reagents would beg to differ. Never the less.

If you don't believe me I can easily show you my warranty and receipt which on the receipt clearly states on there that I returned the vacuum for it having stopped working. Edit: The advice which I gave the poster about the warranty and returning it when it breaks is verbatim what the Harbor Freight employee advised me to do. If this is a misuse of warranty then the blame does not fall on me, I am only doing as I was advised by the employee.

Edit:

I just looked through the (1yr) warranty information and there is nothing in there about it being voided through use in a laboratory or any use other an AC system. It says it the warranty covers failure that results from normal use. It says the warranty doesn't cover damage to the outer surface as a result of environmental factors, or parts that the user is supposed to replace. There is nothing I could see in there that suggests using it in a laboratory (as opposed to an AC system) that would violate the warranty.

If you would like I can try to take a picture of that section of the warranty as proof if you are inclined to believe I am lying.

[Edited on 25-2-2017 by Lillica]

JJay - 24-2-2017 at 19:52

Quote: Originally posted by Lillica

Erm... JJay first of all, I told the Harbor Freight guy exactly what I was doing, he didn't have any objection to it, and on the contrary he was quite fascinated. I told him it broke after a few weeks of me using it and told him that it was being used in a laboratory. He never told me any restrictions about the vacuum warranty or any restricted uses of it.

I was only posting my honest experience which I didn't think was improper or illegal in the slightest, and yet you are now calling me a scammer and even going as far to say I am not a chemist. That's just funny, but I think my collection of some 200 reagents would beg to differ. Never the less.

If you don't believe me I can easily show you my warranty and receipt which on the receipt clearly states on there that I returned the vacuum for it having stopped working. Edit: The advice which I gave the poster about the warranty and returning it when it breaks is verbatim what the Harbor Freight employee advised me to do. If this is a misuse of warranty then the blame does not fall on me, I am only doing as I was advised by the employee.

[Edited on 25-2-2017 by Lillica]

Wrong. You are advising that other people commit fraud. Did you really think you could use your pump with bromine vapors and return it? Seriously?

Lillica - 24-2-2017 at 19:54

Reread my post, I edited it with more information.

I can upload a picture of the warranty, there is nothing in there that says using it in a laboratory would violate it. As a vacuum pump, it says any failure that results from its normal use as a vacuum pump would be covered. The only things not covered are things that result from none use of the pump, such as leaving it outside to rust, along with some other random points, such as loosing it at a repair center.

[Edited on 25-2-2017 by Lillica]

JJay - 24-2-2017 at 20:06

http://www.harborfreight.com/warranty-info.html

"This warranty does not apply to damage due directly or indirectly, to misuse, abuse, negligence or accidents, repairs or alterations outside our facilities, normal wear and tear, or to lack of maintenance." <- You have an ignorant and immoral agenda. You bring discredit upon this community and misguide others. You're a con artist.

This is not the Thieves' Guild; that's two doors down on the right. The only reason we are arguing about this is that you sought to push your agenda. I'm protecting this community by calling you a criminal and denouncing your actions as wrong and immoral. Your attempts to argue about this only serve to distract from the topic and to further cement your own corrupt nature. Begone villain!

Lillica - 24-2-2017 at 20:27

That is not what my 1-yr warranty says. "3. WHAT IS COVERED: Mechanical, electrical, and power failures that occur during normal use and operation. This Service Plan covers Product(s) used primarily for consumer and commercial use"

You cannot sit here and call me an immoral scammer when I was completely honest with Harbor Freight about my use and for doing exactly what the Harbor Freight employee told me. Calling me dishonest implies I had deceitful intentions, which I never did once, nor did I indirectly deceive anyone. Your post is ignoring that fact and is incredibly rude and disrespectful. It is one thing to say that I am misinformed and that the employee was wrong to accept the return, but it is a completely different thing to sit here and slander me when I have done nothing wrong.

JJay - 24-2-2017 at 20:40

I am going to state unequivocally: You are a con artist. You ripped off Harbor Freight. You openly advocated doing so to other members. It is not slander to call you a thief and a criminal because it's fact.

FireLion3 - 24-2-2017 at 21:01

JJay that is pretty messed up, and as far as I can tell from reading over this thread, undeserved.

I agree that returning a bromine-damaged vacuum may be questionable, but if Lillica's warranty covers failures due to normal use and operation, then that is something that sounds like it is open to interpretation of the person handling the return. What constitutes normal use and operation? I would interpret that as any use that a person is supposed to be using that style vacuum for.

Looking at Lillica's posts she just seems like she is trying to help. I don't see anything in her posts that is suggesting dishonest behavior. I think that's crossing the line by calling her names.

-Fire

JJay - 24-2-2017 at 21:05

If he were trying to help, he could have suggested using a water aspirator for filtration.

Harbor Freight may be an easy target for scammers, but that's no excuse.

Texium - 24-2-2017 at 21:07

Quote: Originally posted by JJay

zts16 built some traps to protect his vacuum pump and posted pictures a while back... I think they are on the everday chemistry thread.

Well, unfortunately the traps that I made were very poorly designed and didn't work at all. I got about two uses out of em before they broke and I decided it wasn't worth fixing.

Regarding the Harbor-Freight pumps, I am not "advocating for fraud" but I can back Lillica up to an extent. In the research lab that I work in, we use Harbor-Freight vacuum pumps of various models, and the professor that I work for does exactly what Lillica describes: buys the pump with the warranty, uses it until it breaks (with a dry ice cold trap, but still, with the nearly constant use our pumps get, they still get nasty pretty quickly), and then he gets it replaced as per the warranty. We're talking about a professor at a research university here. Are you going to say that he's a con artist and no real chemist?

I feel that you are taking this situation a little too seriously, and need to take a step back.

FireLion3 - 24-2-2017 at 21:42

Out of all the College/Uni labs I've worked in, 9/10 of vacuum pumps I see being used are the cheap standard oil rotary vane ones, albeit not ivy league institutions. A particular University coming to mind is one which produces a significant amount of published chemistry research papers, with it being one of the more well known engineering universities in the US. Another factor that potentially contributes to this is that many of these pumps are university property and thus likely to be used by inexperienced students just as easily as the researchers using them. Equipment gets passed around, and it's probably not the best idea to let inexperienced students use expensive equipment.

Besides... those Harbor Freight pumps work great, and they aren't that loud either. You're talking about a 0.075 mmhg vacuum source for under $150, which is more than an ample vacuum for many school chemistry settings.

[Edited on 25-2-2017 by FireLion3]

Lambda-Eyde - 25-2-2017 at 12:01

Unless you have easy access to dry ice or liquid nitrogen (even better) to use in a cold trap I can only advise you to use specific filters for specific applications, for example a column of coarse thiosulfate for when you're distilling bromine (if you're into that). This could easily be constructed with PVC tubing for example. I'd wrap the whole thing in electrical tape or something similar in case of a breakage. Change oil regularly, especially when you have good reason suspect contamination. Use a buffer reservoir between your pump and apparatus, like a three-head flask with two hose nipples on the sides and a manometer in the middle. This way you get a more stable vacuum and you won't have any issues with oil coming out of your pump and into your newly fractionated substance...

Even better would be to keep an eye out for a PTFE diaphragm pump on eBay, they can sometimes be had for nice prices and are almost indestructible.

Quote: Originally posted by JJay

Harbor Freight may be an easy target for scammers, but that's no excuse.

Yeah, those poor, hardworking owners of a multibillion franchise...

Seriously.......

macckone - 25-2-2017 at 18:17

The harbor freight pumps are intended for A/C use.
But the warranty doesn't limit them to A/C use.

Now what would A/C use expose the pump to?

Short list: HCFCs, CFCs, Ammonia, HF, HCl, F₂, Cl₂, LiBr, HBr, Br₂.

The free halogen and halogen acids are breakdown
products when the systems overheat and get air
in them. But these are expected to be encountered
in normal A/C service. Service techs are trained
to deal with this during the purge cycle and
respirators and other precautions are recommended
for large units. HF and HCl formation are often
the cause of A/C failure once the absorber capability
is exhausted.

Note that Lithium Bromide is used in commercial
absorption units and bromine gas is an expected
agent found in these units when they require
servicing. A stabilizer is added to reduce bromine
formation. I expect they are meant to deal with
trace amounts from odd side reactions with
lubricants and additives vs straight bromine vapor
but exposure is on the list.

So no, bromine gas may not be good for them.
But it is most definitely in the list of things they
can expect to be exposed to. So JJay is definitely
wrong in saying bromine vapor is not in normal
use. Even in the limited realm of A/C maintenance.

JJay - 25-2-2017 at 19:44

As someone who has worked in industry as a refrigeration plant operator, I can assure you that macckone has no idea what he's talking about. While it is true that refrigeration units have purging devices used for eliminating problematic substances, those pumps are not used as part of the purge cycle, and using them to handle refrigerants in liquid state also voids the warranty; they're used for eliminating the last traces of refrigerants prior to charging the system or for utility use when refrigerant / etc has made it into the wrong part of the system. Suggesting that they get exposed to halogens is like suggesting that pharmacists who sell homeopathy products are vending mercury and arsenic for internal use without a prescription as justification for serving spoonfuls of mercury to children. Far more worthy of note and concern is the formation of phosgene in such systems, an actual phenomenon which macckone neglected to even mention.

If a professor is committing fraud, he should be denied tenure. If a tenured professor is committing fraud, there's a serious problem. Most university labs use actual lab pumps for lab use, when they use them.

Also, those pumps are way too loud IMHO, and when used close to atmospheric pressure, they spew a mist of oil vapors that I personally don't like being around. I have one, but trust me, the warranty is completely void.

[Edited on 26-2-2017 by JJay]

macckone - 25-2-2017 at 23:34

JJay, No one mentioned halogens being handled as
liquids through a vacuum pump. In many pumps
liquid is going to cause immediate failure.
You seem to be confusing refrigerant recovery with
purging.

Hot a/c systems can break down CFCs and HCFCs.
Halogens and acids are normally formed as part of
refrigerant aging. And yes even phosgene is formed.
In automotive systems for example, a receiver/drier
is included that has an moisture and acid absorber.
In industrial systems, these are separate.

If it has enough acid to cause the system to fail,
it certainly has enough to impact a vacuum pump.

A quick search is enough to show this is not the
same as homeopathy:

https://www.google.com/search?q=acid+in+a%2Fc+systems&ie...

Acids and halogens are seldom more than .1% but that is not at
all the same as homeopathy because in homeopathy the ratio
is zero.

If corporate employees are advising a device is
appropriate for a use and a warranty will cover
that use, then in most states utilizing the device
for that use and utilizing that warranty is a
protected right, not fraud. Ie. any advice a sales
person gives establishes a fitness for use.

Note that the harbor freight standard warranty
also says normal use without defining what
normal is because they sell a huge variety of products.
Which is why the fitness for use is important.
As is what can 'normally' be found in an a/c system.
And yes, halogens and their acids can be found in those
systems in quantities that could damage pumps not
designed for such use.

Standard I am not a lawyer disclaimer.

You are claiming professors and forum members
are committing fraud when that is not the case.

As for the original poster's question, an automotive
receiver/drier might be exactly what he is looking for
but they are not reusable devices. And $20 in the US
is a bit pricey considering this is going to be basically
a single use. The equivalent industrial units have
replaceable cartridges but they are big and expensive.

JJay - 26-2-2017 at 00:06

Quote: Originally posted by macckone

JJay, No one mentioned halogens being handled as
liquids through a vacuum pump. In many pumps
liquid is going to cause immediate failure.
You seem to be confusing refrigerant recovery with
purging.

Hot a/c systems can break down CFCs and HCFCs.
Halogens and acids are normally formed as part of
refrigerant aging. And yes even phosgene is formed.
In automotive systems for example, a receiver/drier
is included that has an moisture and acid absorber.
In industrial systems, these are separate.

If it has enough acid to cause the system to fail,
it certainly has enough to impact a vacuum pump.

A quick search is enough to show this is not the
same as homeopathy:

https://www.google.com/search?q=acid+in+a%2Fc+systems&ie...

Acids and halogens are seldom more than .1% but that is not at
all the same as homeopathy because in homeopathy the ratio
is zero.

If corporate employees are advising a device is
appropriate for a use and a warranty will cover
that use, then in most states utilizing the device
for that use and utilizing that warranty is a
protected right, not fraud. Ie. any advice a sales
person gives establishes a fitness for use.

Note that the harbor freight standard warranty
also says normal use without defining what
normal is because they sell a huge variety of products.
Which is why the fitness for use is important.
As is what can 'normally' be found in an a/c system.
And yes, halogens and their acids can be found in those
systems in quantities that could damage pumps not
designed for such use.

Standard I am not a lawyer disclaimer.

You are claiming professors and forum members
are committing fraud when that is not the case.

As for the original poster's question, an automotive
receiver/drier might be exactly what he is looking for
but they are not reusable devices. And $20 in the US
is a bit pricey considering this is going to be basically
a single use. The equivalent industrial units have
replaceable cartridges but they are big and expensive.

You missed the point. Liquid refrigerants are commonly kept in A/C systems, but you can't just run those through the pump. Also, my concern was that you were confused about purging cycles, so it seems odd to see that accusation directed towards me.

I'm not sure what you think these pumps are used for, but you don't just hook one up to a refrigeration system that contains a hundred PPM (that's 0.01%, which is far less than the grossly exaggerated figure you quoted) of hydrogen chloride and pump it out into the atmosphere. You certainly don't submit one to conditions where it is handling hot, undiluted halogen vapor at atmospheric pressure. They're typically used on systems that are thought to be pretty much empty, and the amount of halogen vapor is extremely tiny considering the capacity of the pump.

You're making misleading statements suggesting that these pumps are intended to handle corrosive and toxic substances. Regardless of whether you are motivated by ignorance or malice, and in your case, I don't think it's malice, it's inappropriate.

my two cents worth ....

Sulaiman - 26-2-2017 at 02:22

Quote: Originally posted by LD5050

I would like to know what people here use for there vacuums and maybe shoot some ideas back and forth about building some kind of filter.

I have a dual stage rotary hvac pump that I rarely use for chemistry due to the problem of trapping contaminants.
Dry ice or liquid nitrogen are beyond my hobby budget,
so the best that I can do is, as mentioned by Lambda-Eyde, to use the pump only when there is a specific trap that works for whatever I'm working with.
e.g. buble acidic gasses through a basic solution, basic gasses through an acid, water vapour through sulfuric acid, calcium chloride, dry cotton wool etc.
And in ALL cases a trap is required to protect against liquids getting to/from the pump.
(how could a liquid get to the pump ? ... too easily when things don't go quite as planned

Frankly, buying the dual rotary was more of a want than a need,
I mostly use my cheap little eBay 12 Vdc -80kpa pump,
so far for filtering as I've not done even one 'proper' vacuum distillation yet, just messin' about.

To illustrate the problem,
my -80 kpa pump allows water to boil at about 63C, so cold water will work fine in a condenser.
my rotary boils water down to 0C ! ... how can I condense that ?

Volatile solvents boil/vapourise at even lower temperaturs - no way I can make a cold trap for them.

Cheaper than a trap would be to keep your rotary until you need it, and buy a cheap vacuum pump

e.g. if you have a water tap in your lab then a water aspirator is an excellent choice IMO
glass: http://www.ebay.co.uk/itm/CHEMISTRY-GLASS-DISTILLATION-APPAR...
metal: http://www.ebay.com/itm/Laboratory-Aspirator-Pump-Humboldt-V...

I have been using one of these http://www.ebay.com/itm/New-DC12V-80Kpa-DC-Micro-Piston-Vacu...
for a couple of years and I can recommend it for vacuum filtration etc.
I use a pvc pipe on the exit port to share my fumes with the neighbourhood,
water aspirator vacuum pumps automagically dipose of fumes.

The other 'problem' with rotary pumps is that to use one 'correctly' for a distillation etc.
it is neccessary to measure the vacuum, suitable vacuum gauges may cost more than your pump !
__________________________________________________

Jeez ... it's no wonder there is war in the world ... see how we get riled up over simple misunderstandings - as in this thread above, (and far too many others).

my own opinion is that, based on the tone of the initial posts,
Lillica acted in good faith without intention to defraud as (apparently) he told no lies and did not try to evade the truth,
if it is policy to honour all warranties regardless uf usage (quite possible as a marketing expense) then sharing this news with us is a good thing.
(e.g. we offer a one year warranty on all repairs that we do at work, with all the usuall disclaimers,
but for customer relations we often repair under warranty failures due to accidental misuse, or maybe a little over the warranty period etc.)

Equally I can see the 'purist' view of JJay,
a hvac pump is not meant/intended/designed to be used as we would

so to claim under warranty is morally unreasonable.

My own approach would have been as Lillica , ask if it IS covered.
If harbour Freight have no-quibble warranties for P.R. reasons ... GREAT.
(e.g. of all of the recommendations for rotary vacuum pumps here at SM,
Harbour Freight get the most recommendations by far, so maybe they feel it is worth the occasional warranty,
especially as they want you to buy more than just vacuum pumps)

Maybe I'm a moral reprobate too ? ... after all, I did buy 2x 500ml 3-neck flasks for £3 each

[Edited on 26-2-2017 by Sulaiman]

JJay - 26-2-2017 at 02:52

I really miss my Fisher pump. It had a retail value of something like $4000, but I picked it up lightly used for a mere $200 plus freight charges. It was quiet and didn't spew an oil fog, and the vacuum was very powerful....

I don't know if you're a moral reprobate or not, but you'd better figure it out before you call up the insurance company like, "Hi, I'd like to rip off some insurance money - any ideas??"

Sulaiman - 26-2-2017 at 03:00

I am bidding on a lovely diaphragm pump at the moment

http://www.ebay.co.uk/itm/272566987930?_trksid=p2060353.m143...

[Edited on 26-2-2017 by Sulaiman]