Simple DIY Vacuum Chamber and Pump

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About: I make musical instruments the modern way, with a CNC. check out my video content on https://www.youtube.com/user/TwoCherriesIns

This is an easy to build vacuum chamber that is power with a garden hose.  you can draw 30 cm of vacuum with your hose. simple and easy way to degas fluids like silicone for mold making without buying an expensive vacuum pump.

Step 1: Parts

you will need the following parts. many of they can be found or scrounged for free is you have the time.

1 - 6" x 24 " PVC pipe                                Lowe's                                       $16
2 - 1/4 " x 12" x 12" acrylic sheets           (www.estreetplastics.com)   $12
2 - 1/ 8" x 12 " x 12" neoprene sheets   (www.smallparts.com)           $20
1 - vacuum Aspirator                                 (csrscience.ecrater.com)      $25
1 - vacuum gauge                                     harbor freight                            $13
1 - 3" x 3/8" air hose                                  harbor freight                            $4

                                                                                                                                                                 Total = $90


Step 2: The Vacuume Asparater

this little thing can draw up to and in some cases even more than 30cm of vacuum with only a garden hose. and a only $24 it beats the hell out and expensive pump. it has a ball valve to hold the vacuum when the water pressure changes so when you shut of the hose the vacuum stays.

Step 3: Top and Bottem

The top and bottom are 1/4 " acrillc .
Just trace the tube.
Find the center point, and make a circle and inch farther out.
cut along the outside line.

Step 4: Neopreen Gaskets

use the top and bottom pieces to trace around with a knife to cut out the neoprene.
find the center and then cut out the center circle by hand.

Step 5: Make the Conections

drill tow hole just a little bit smaller than the fittings (the vacuum gauge came with a bunch of extra fittings)
heat up the fitings with a soldering iroen and scre them in. when they cool down take them out and wrap with plumbers tape and reinsert them.

Step 6: Finishing the Pvc Edges

This is the tough part. if you are lucky the pipe you have will have good edges. This one did not. gab a piece of sandpaper and hold it down with the bottom plate. sand in a circular motion and keep turning the pipe so you don't over sand. Eventually you will get an edge that is good enough for the neoprene.

Step 7: Set It Up and See If It Sucks...

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    81 Discussions

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    ThomasS59

    1 year ago

    This is also called an jet pump. Fire a solid stream out of a garden hose you see the surface of the jet is often not smooth. Air is caught by the water stream and is accelerated to the water speed. The water is expanding as it flows. So it contacts the tube ID but since the surface is ruff of the water jet is traps air in pockets that move with the water to the outlet of the tube. Thus air is removed. The maximum vacuum that can be obtained is the vapor pressure of the water at it's temperature. 30cm or 300 torr or mm of Hg corresponds to about 76C. Thus this is not a very efficient pump at city water pressure of ~60 psi. Connect this to your spray washer with more pressure and if it can deliver the flow the vacuum would be greater. Other choices is a gas ejector compressed air would be the choice of a DIY project but steam in the industrial choice 30 years ago. about 20% peak efficiency. Here is a source "JET PUMPS AND EJECTORS" Green, Andrew J. DOI: 10.1615/AtoZ.j.jet_pumps_and_ejectors.

    The next solution is a liquid ring pump which is where industry have gone. They are simple machines that could be made with simple hand tools and plastic sheet stock and fine powder filled glue or silicone rubber. Where the powder size sets the gap between the waggon wheel hub and spoke shaped rotor and the housing with the driving shaft off set, eccentric, from the housing center of a round hole in the sheet of plastic the rotor could have been made from. In and out ports on opposite side plates. The ID is the wheel hub OD, OD is the circle concentric with the housing hole and just touching the hub diameter less the desired seal radius height. The remaining side and the radius on the ID/OD intersection is determined by the angle between spokes. At no time shall the inlet and outlet not have a spoke between them. These pumps get down to the vapor pressure of the liquid. Ice water vapor pressure is 5 torr. One nice thing about liquid ring pumps is that you can put fire, dust, grit, and liquid into them and they continue to turn. a little water is added to keep the temperature low and insure the ring is held at the correct height.

    http://www.wintek-corp.com/liquid-ring/how-liquid-ring-works.html

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    rogersbr

    3 years ago on Step 7

    is there a way to make a vacuum system to get to about 10^-5 torr ?? i have ideas but the problem is sealing it

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    KDS4444

    4 years ago on Step 7

    Um... What about the "pump" part? You showed several brass attachments and you mention a garden hose, but there's no pump here anywhere or am I missing something? Because a vacuum chamber without a pump is just a pretty tube.

    8 replies
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    bassman76jazzKDS4444

    Reply 4 years ago

    that is the pump. it uses the a garden hose to pull vacuum.

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    KDS4444bassman76jazz

    Reply 4 years ago on Introduction

    I don't seem to understand where the garden hose attaches or how it draws the vacuum. You have laid out all of the parts of your vacuum chamber, but I don't grasp what "mechanism" is actually "pumping" the air out of it (you say this is a garden hose, and I believe you, but I don't know how to attach one to this to cause it to draw a vacuum).

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    HieuKDS4444

    Reply 4 years ago on Introduction

    So you are not understanding the definition of "aspirator" then as Bassman pointed out. The garden hose attach to the end he cut and hose clamped the aspirator to the chamber.

    From the physics of things as they are presented here -- the water running draws the air away from the that tube he made air-tight creating a vacuum chamber. A vacuum pump is just something that draws out all the air/fluid from whatever space you need to be left completely devoid of air/fluid. So he did in fact create a vacuum chamber and pump as he stated in his title. If you still don't believe this you can just look at the vacuum gauge and see for yourself if you build one.

    A little physics lesson if you still need explanation. As the water rushes out of the garden hose and pass by the tube he created it draws air away from it. As no air can enter the chamber, ultimately the chamber will be left completely empty of air.

    So water rushing by the chamber is THE PUMP.

    aspirator-definition.png
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    KDS4444Hieu

    Reply 4 years ago on Introduction

    I am understanding better, but why does the pump not just start to fill with the water? What keeps the water from filling the vacuum created as it sucks out the air?

    There is no pump.There is only a water hose (e.g. a garden hose) with water running through it. Into this hose, another hose has been attached, and this hose goes to the vacuum chamber. The connection of the hoses is shown in the 1st picture in "Step 2: The vacuume asparater". The thin pipe outlet is for the hose that goes to the vacuum chamber, and the water runs through the thicker pipe (direction does not matter).

    As water running through the pipe will draw fluid (gas and liquid) from the connected, thinner pipe, a vacuum starts to build into the vacuum chamber. This is known as the Bernoulli principle / the Venturi effect. (Both dudes made huge contributions to the field of fluid dynamics, and I am so waster ATM that I cannot remember which one dealt more with this phenomenon...)

    You can see this effect in real life, for example, if you have access to a (small) motor boat that has a (corked) hole on the bottom (to drain out rainwater): Get some water into the boat, go for a ride and when the boat is moving at a decent speed, pull out the cork. The water in the boat will get drawn out, and after it's all gone, air will get sucked through the hole (not that you will notice it).

    You either have to run the water as long as you wish to have the vacuum, or install a valve into the vacuum chamber hose and close it when you have reached the maximum vacuum (recommended).

    Nevertheless, as I wrote earlier, if you by any means can scrape together the 60USD that a vacuum pump costs, do not even consider this water thing. You would need a 'weapons grade' water pump to get enough vacuum for e.g. stabilizing wood.

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    BruceC2Hieu

    Reply 4 years ago on Introduction

    Nice explanation, but kind of an assholish and snarky tone.

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    en2oh

    3 years ago on Introduction

    nice instructable just one question. How can a vacuum aspirator using water as the working fluid generate a pressure of 30cm of water? If I recall correctly, the limit for that type of pump is the vapor pressure of water at any given temperature I.e. The pressure where water boils at the temperature the pump is operating at. At 25 deg C, that's about 24torr or 24mm Hg. 30cm of water is about 22mmHg wouldn't your water start to boil at 24 mm Hg? You could cool the water some, but this is a practical limit to a vacuum aspirator

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    nsalling

    3 years ago on Introduction

    I really like your Vacuum chamber, it was really cool. I do have a small question: I found a pressure sprayer (one like this: http://tinyurl.com/onke786 ) and got the idear that i could make it into a vacuum, chamber. Do you think that is possible?

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    RyanG18

    4 years ago on Introduction

    if you used a 1/2 or 1/3hp submersible pump, you could connect it up to that and get crazy water pressure (much, much higher then you can get from a garden hose) - and you could recycle the liquid back into the same water basin you are drawing from - so it'd be a closed system with the power source being the electricity powering the submersible pump

    1 reply

    That is true. I reckon a pressure washer would work also nicely. However, the pressure itself does not matter, only the flow rate of the fluid. Thus, you obviously want to make the water hose as short as possible and/or have a large diameter that reduces only just around where the air tube is connected.

    Then again, as you can buy a Chinese low-quality vacuum pump for, what, 50-60USD, nowadays, I wouldn't really even consider anything that uses the Bernoulli principle / Venturi effect. Unless, of course, if you have no electricity available. Otherwise, an electrical pump is the way to go: better vacuum, no worries about the water (easy to use indoors), less electricity consumed as with a water pump, etc.

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    rf

    7 years ago on Introduction

    The big production with the 6" tube, acrylic and neoprene was to create a vacuum reservoir?

    That 6" tube has end caps and all kinds of other fittings waiting at the hardware store to be used with it. One or two end caps and some glue would seem to simplify things quite a bit. Or perhaps I'm missing something. If you want the ends to be removable there are threaded fittings too.

    End caps are nice and thick and can be drilled for smaller fittings too.

    Just a thought.

    2 replies
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    bassman76jazzrf

    Reply 7 years ago on Introduction

    for one i wanted to see into the chamber and the end caps are rounded not flat so its difficult to degases fluids without a flat bottom. i actuality was looking for a pressure cooker at the thrift shop but i did not find one. also the fittings for 6" pvc are about the same price as the acrylic.

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    rfbassman76jazz

    Reply 7 years ago on Introduction

    What you want is a bell jar. They're really not that expensive. You can get a 14-inch diameter bell jar for about the same cost as your materials here. And you can see into it much better.

    Not that you didn't learn a lot building yours.