Author Topic: ghetto suction for vacuum filtration  (Read 5675 times)

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stratosphere

  • Guest
ghetto suction for vacuum filtration
« on: October 02, 2003, 06:46:00 PM »
i was rather surprised to not see this mentioned anywhere, i hope that it is not because it is too trivial, but some one who bears an uncanny resemblance to me, found that the utility hose on a regular household vacuum cleaner was a satisfactory source of suction for vacuum filtration.
much much better results then regular gravity filtration.

i would go on about how to couple the vacuum hose to the side arm (or equivalent orfice), but i would suspect most can solve this dilema on their own with a trip to the hardware store.

obviously if large amounts of ether or some other highly volatile/flammable solvent are involved, one might opt to not use this method.

Osmium

  • Guest
> i was rather surprised to not see this...
« Reply #1 on: October 02, 2003, 07:29:00 PM »
> i was rather surprised to not see this mentioned anywhere,

This idea has been discussed and shot down before.
The vacuum that can be produced by a vacuum cleaner is very small and not suitable for many filtration operations.
And then there is the danger of a fire.


cublium

  • Guest
You can get used pumps almost for free(like...
« Reply #2 on: October 02, 2003, 07:39:00 PM »
You can get used pumps almost for free(like ref. compressor)

halfkast

  • Guest
think fun
« Reply #3 on: October 02, 2003, 09:28:00 PM »
If you look up a post by SHORTY about subliming I2, you'll find a device that uses a household vacuum cleaner that I played with at the end of the thread, it works well with easy fine-tuning, heh but the safety comes after the fine-tuning.  ;D

I can think of devices to create small amounts of vacuum safely enough but it probably isn't worth the effort. Then again it could bee fun and rewarding?
These are the rules:

-it should give a nice increase in rate of filtration.

-no flammable vapor will ever travel down the vacuum cleaner tube.
-no liquids will ever travel down the tube.
-it can't bee a completely closed system, or atleast a completely closed system for extended periods (seconds) itll stress the vacuum cleaner motor.


I will do it myself if you don't take the glory
  :)

Maybee you can think of a device either manual or using a vacuum cleaner? And tell us about it.

Long balloons, plungers, water, tubes, plastic fittings. anything.

Why dont you think of something really out there? like what? Like a bloody tube or cyllender that sits on the roof with a turbine to create a small vacuum for whenever you need it?  8)

Osmium does positive pressure pushing a liquid through a filter papaer stress it more than the usual negative pressure?


Osmium

  • Guest
Sheesh people, how hard is it to simply BUY a...
« Reply #4 on: October 02, 2003, 09:51:00 PM »
Sheesh people, how hard is it to simply BUY a cheap ass plastic ass-pirator?
Or even build one yourself in case you really cannot find one for sale?

> Osmium does positive pressure pushing a liquid through a
> filter papaer stress it more than the usual negative
> pressure?

Yes. While the pressure difference between inside and outside can only be 1 bar in a vacuum filtration(you cannot suck a negative pressure), you can of course apply more pressure when pushing the liquid through the filter. That's called pressure filtration.


halfkast

  • Guest
Yeah your probably right, its just messing...
« Reply #5 on: October 02, 2003, 11:24:00 PM »
Yeah your probably right, its just messing around really.

Right ;) , so there's no preference from the filter paper's perspective whether a liquid is being pushed through it or sucked through underneath?

I suppose this pressure filtration would bee better for substances sensitive to air maybee, right?  :)


stratosphere

  • Guest
for some applications high vacuum isn't real...
« Reply #6 on: October 03, 2003, 12:34:00 AM »

Osmium

  • Guest
> so there's no preference from the filter...
« Reply #7 on: October 03, 2003, 12:57:00 AM »
> so there's no preference from the filter paper's perspective
> whether a liquid is being pushed through it or sucked through underneath?

Yes of course there is. If you use a pressure of 10 bar then the pressure difference is 9bar and the paper might tear, or some of the solids might be pushed through the paper.

> the high flow rate of air a vacuum cleaner can provide
> pulls plenty of solvent out.

Once the pressure is down the "high flow rate" of a vac cleaner is exactly zero.

> i don't see why an aspirator would be any better,

I do. From personal experience, you should try it out sometime.

> they don't pull a high vacuum either,

15mbar compared to an estimated 250mbar looks like a pretty big difference to me.

> they have less flow rate,

They still work much better than a vac cleaner. Flow rate doesn't really matter in this case.

> you got to have a sink nearby and leave the water on full blast,

Big deal, the water flowrate will go down dramatically once full vacuum is attained.

> most people already have a vacuum cleaner handy.

Most people also have a faucet and sink.

> as far as a real vacuum pump

An aspirator produces a vacuum which is much more real than the vacuum cleaner.


stratosphere

  • Guest
needs a hearing aid?
« Reply #8 on: October 03, 2003, 01:26:00 AM »

chilly_willy

  • Guest
correct..
« Reply #9 on: October 03, 2003, 03:40:00 AM »
Not to mention the noise of a vacuum cleaner roaring away to distill 100ml worth of liquid.  I know we are beating a dead horse here..but yes get a free fridge pump!!  I wrote a really long post on this a long time ago on where to get one (for free) and how to easily convert it.  Check it out....

Post 13893 (missing)

(chilly_willy: "Pull 29" Hg For $25 or less..", Chemicals & Equipment)
or UTFSE!!


cublium

  • Guest
Even better
« Reply #10 on: October 03, 2003, 05:49:00 AM »

cublium

  • Guest
Where the misinforming part?
« Reply #11 on: October 03, 2003, 03:54:00 PM »
Where the misinforming part?You guys have no sense of humor. :P

Rhodium

  • Guest
The last part is incorrect.
« Reply #12 on: October 03, 2003, 04:26:00 PM »
Smileys was invented to convey humour across the internet, without them a lot of irony becomes misinformation. Also, the chemistry forums are not a place to joke around unless you have something constructive to add to the thread as well.

stratosphere

  • Guest
not to beat the dead horse even more, but i...
« Reply #13 on: October 05, 2003, 08:42:00 PM »
not to beat the dead horse even more, but i wasn't  using it for vacuum DISTILLATION, it was used for filtration purposes.
 someday i will surely upgrade to a real vacuum pump, but hey, i don't have cash to spare and i needed to suck the liquid through the filter then, not in a few days.

armageddon

  • Guest
if you really need to...
« Reply #14 on: August 08, 2004, 09:58:00 PM »

p2e3r4f5e6c7t8

  • Guest
Wiring diagram
« Reply #15 on: August 11, 2004, 06:56:00 PM »
Dose anyone know were i could find a wiring diagram for a fridge compresor ?
Swip scored a shiping contaner refrigeration compreser the other day and there is no wiring on it and swip dosent wana have to get an electriction do if for him and then get charged $120 labour, Plus the parts cost(if it needs parts).
And also a normal fridge compreser wiring diagram wouldent hurt either because swip has quit a colection of them at the moment and wouldent have a fucking clue about how to wire it up :(  :-[


Shane_Warne

  • Guest
Can aspirator fittings be bought?
« Reply #16 on: August 13, 2004, 02:51:00 AM »

ozmosis

  • Guest
vacuum filtration
« Reply #17 on: August 14, 2004, 04:45:00 AM »
This vacuum pump combines excellent suction capacity with limited water consumption both at low pressure (0.5 to 1 Kg/cm2) and high pressure (10 Kg/cm2) operation. The built-in non-return valve protects the pump from possible water back-flow. Made of polypropylene for excellent resistance to chemicals and autoclaving.

Easily assembled after cleaning.
For example: Operating pressure: 1 Kg/cm2
Attained vacuum: 15 mm Hg residual pressure.
Evacuating 5 litre container: aproximately 20 minute

ozmosis

  • Guest
and,
« Reply #18 on: August 14, 2004, 05:38:00 AM »
Laboratory type filter pump made of chrome-plated brass. Can be operated on water or compressed air. This heavy duty pump produces satisfactory vacuum, even when the water (or compressed air) pressure is low, i.e. it requires little water (or compressed air) for its operation. The fact that the pump is fitted with a NON-RETURN VALVE ensures the maintenance of vacuum, even when the water or air supply is interrupted.

ozmosis

  • Guest
aswell as,
« Reply #19 on: August 14, 2004, 05:46:00 AM »
Light, portable hand-operated vacuum pump, with optional vacuum gauge, and high suction capacity.
With a few squeezes it attains a vacuum of 625 mm Hg (25").
Pumping rate is 15cc per stroke.
Fitted with valve to release vacuum without disconnecting pump from line.
Two-way pumping action for transferring liquids in either direction.
Nozzle fits standard 1/4" I.D. tubing.

ApprenticeCook

  • Guest
ctrl+c & ctrl+p
« Reply #20 on: August 14, 2004, 12:43:00 PM »
Easy as 1,2,3.....

Anyway... the above aspirators are very good and very cheap so they are excellent for many applications, one swim has seen got to 27"Hg on tap pressure (which was quite low in the particular area) so they are excellent.

For vacuum filtration you only need a small vacuum (most times) so the hand pump is quite ok here... but just another aspirator on a slow tap would be sufficient.

As for ghetto there have been a few threads on making aspirators so utfse for that information.
As for an NRV as seen in these aspirators, they can be bought from car part stores for vacuum purposes in the car (i think they call them vacuum isolators?) so thats an easy way to make yourself an aspirator with and NRV inline...

-AC


Shane_Warne

  • Guest
As for an NRV as seen in these aspirators,...
« Reply #21 on: August 14, 2004, 03:11:00 PM »
As for an NRV as seen in these aspirators, they can be bought from car part stores for vacuum purposes in the car (i think they call them vacuum isolators?) so thats an easy way to make yourself an aspirator with and NRV inline...

An en-ar wot?  ;D

I think you could be right about the automotive industry. I saw a website that refered to a device that sounded like a bernoulli principle driven vacuum.
But when I chased it up, I thought they were talking about an overly large interpretation of the device - maybe not.


Venturi adapter/fitting might turn up the treasure.  :)

ApprenticeCook

  • Guest
i dont know what they call them but its a...
« Reply #22 on: August 15, 2004, 05:14:00 AM »
i dont know what they call them but its a little inline thing for the vacuum pipes in your car...
i have a few they fit 8-14mm tube and have a cylinder in the middle of the 2 pipe fittings, in which there is a little rubber circle that presses up against a stopper when air (is from vacuum being drawn through) is being sucked toward the vacuum source and allows the flow, however when you reverse the flow (ie suckback) the stopper is not at the other end and is pushed back immediatly and covers the hole at the other end, preventing loss of vacuum...
Oeverall size is 2.5" long (including tube connections) and 1" diameter.

They would not hold under chemical abuse so a catch system to filter anything off is required....

I thought thats what the packet said, but i cant remember accuratly, it was a while ago, you buy them in single blister packs from major auto stores...

-AC


Shane_Warne

  • Guest
Venturi Tee. I've found PVC and Copper, which...
« Reply #23 on: August 16, 2004, 04:32:00 PM »
Venturi Tee.

I've found PVC and Copper, which I already had, but thought they were unsuitable.

A PVC venturi tee, plus PVC tubing nozzles should make something similar to noj's.

I just hope the constriction is smooth on the inside of the finished product.

biffman

  • Guest
I believe it is called a PCV valve.
« Reply #24 on: August 22, 2004, 05:14:00 PM »
I believe that the one way valve for automobiles that you are talking about is called a PCV valve.  Which stands for Positive Crankcase Ventilation (or something very similar). It only allows flow of air in one direction and is a simple but basic part of the engine's overall emission reduction equipment.
  They are extremely cheap to buy in almost any automotive parts supply place.

Shane_Warne

  • Guest
biffman, that's the solution. thanks!
« Reply #25 on: August 23, 2004, 06:52:00 PM »
biffman, that's the solution. thanks!

I've seen PVC vavles (well, 2min ago) and that's exactly what I've been looking for.

There's some straight ones, and some Tee-shaped ones, depending on the make of car, by the sounds of it.

I wonder if you can use a Y-piece to run two aspirators off a single pump, and combine the vacuum with another Y-piece after the vacuum nozzles?

biffman

  • Guest
Don't know for sure
« Reply #26 on: August 23, 2004, 08:13:00 PM »
I have never used PCV valves for any sort of vacuum so I don't know how much pressure difference they will be able to seal against.  But they are so cheap to buy it's easily determined.  One note; if you want to use a used PCV valve to check it give it a shake.  You should hear a clicking inside like something moving back and forth.  This is good.  If you don't hear anything moving back and forth inside it is probably no good and should be replaced. I think they're $5-$10 (at most) at the auto supply store.
  If you do hook one up for lab work post your results here.    I'd like to know how well they can hold a vacuum.

biffman

  • Guest
By the way it's PCV not PVC
« Reply #27 on: August 23, 2004, 08:18:00 PM »
The valve itself is referred to as a PCV valve which means Positive Crankcase Ventilation (I believe) not PVC which stands for Poly Vinyl Chloride.
  Althugh the housing of a PCV valve may very well be composed of PVC, asking for the valve by the proper name (a PCV valve please)at the parts supplier makes you look more edumacated.

Shane_Warne

  • Guest
The only problem is by the looks of it, is...
« Reply #28 on: August 24, 2004, 05:29:00 AM »
The only problem is by the looks of it, is that there's so many different types for different car models.

they also probably come in one size for the specific car.

The valve is going to cause turbulance with the flow of water, but maybe itll work alright. Especially temporarily.

those PCV's look like they'd be good fittings for vacuum drying too.

anyway thanks for the info biffman, and you too for posting those pictures ozmosis and AP...I'd like to thank God, my mother, for making this vacuum source possible.

ApprenticeCook

  • Guest
use the pcv after a catch system so only air...
« Reply #29 on: August 24, 2004, 09:50:00 AM »
use the pcv after a catch system so only air travels through it otherwise you will start to corrode it...

my nrv (what i call them... pcv equiv) is right next to the aspirator so its after a filter system to prevent its demise...

Just a thought in system design.
-AC


Snakebyte

  • Guest
If you already have a fridge compressor I...
« Reply #30 on: September 01, 2004, 12:21:00 AM »
If you already have a fridge compressor I would use that.  It is great for filtration as it should suck 27-28" and its almost silent.  Swim's has 2 wires of which would be attatched to an ordinary plug for a 110 outlet(doesn't matter which is hot and ground as it is AC).  Since they don't have switches you'll have to wire one in on 1 of the wires.