Homemade Vacuum Pump

[hilerioal@outlook.com]

Fantastic! I couldn't tell looking at the video but what is the max vacume psi on your machine? Thank You

[Karl_H]

With no refrigerant in the system, is it necessary to oil the compressor?
If so, how?

Thanks.

kh

[marksbug]

when I was a kid ( 55+years ago)dad had a old compressor that he used for the ac suck downs and for aring up our tires too, remember if it sucks, it also blows!!!!I think it's still at dads.it has fallowed up around the us and world too as I remember having it in japan too. I think it was about a 3rd smaller than what the op has. super quiet and always works.
they should pull 29 inches. as for oil just dont dump out whats in it already.the oil circulates through the system with the freeon.. thus you probably dont want to use this compressipor for air brush....

[DIYer]

Thanks Sam's Workshop Diary! We've added your Vacuum Pump to our Miscellaneous category,
as well as to your builder page: Sam's Workshop Diary's Homemade Tools. Your receipt:

Vacuum Pump by Sam's Workshop Diary

tags: pump, vacuum

[tonino]

I build this vacuum pump out of an old fridge compressor.
I want to use it to stabilize wood with oil or resin.

In my younger days I used to manufacture and instal hot water solar heating systems. Filling the system with a water based heat transfer fluid used to take forever and you could never be sure you had got rid of all the air out of the system. You had to check several bleed points, always in awkward places. I eventually thought of filling using a vacuum pump. New pumps were very expensive so I had to work out how to make one. I used a pump off an old refrigerator, probably 20 years old. A very small British refrigerator about a quarter the size of an American fridge. I would void the system at its highest point, then introduce the heat transfer fluid through a separate filler point. Part of the vacuum system was an overflow, glass container. As soon as this started flowing I knew the system was full with no airlocks. The benefits to me were a saving of about 2 hours manual pumping and bleeding the system. No chance of airlocks, no spillage of expensive fluid. I used that same pump for another twenty years. Central heating intallers could well make use of this system of filling a heating system.
Thanks for tickling my memory.

[tonyfoale]

Hmmm, running a vacuum port [eductor] hadn't occurred to me. The multiple pumps address volume in what seem economical fashion....Thinking now to pull it down with venturi [a little harder to control], and maintain it with a pump.

Here is my venturi thingy.

Click thumbnail for full size images.


Here is the power brake vacumn pump to compensate for the lack of manifold vacumn in diesel engines. This was driven off the end of the camshaft, so around 3000 rpm should work really well. They have a good flow rate and suction but I have no real data.

[PJs]

Hmmm, running a vacuum port [eductor] hadn't occurred to me. The multiple pumps address volume in what seem economical fashion....Thinking now to pull it down with venturi [a little harder to control], and maintain it with a pump.
Until I finish the lid [bell jar] and jar hoisting sling, the seal is a question mark. Initial plan positioned it open end up, too high to reach down into, and quite heavy. bought lab grade bell at auction long ago, about 14mm wall. Definitely not the thin terrarium or display variety. Now, closed end up, vessels seat on an easy flat surface.
Per the usual, design process [skilled cobble-up] just as fun a real build. BTW, lab bells this size are ~$750, displays ~$50...crackerbox thin. So, extra care is rewarding. The sling is [might be] a stretched bicycle inner tube, three long webbing legs, terminated with a ring.

TM51, I am assuming you will be using the Humongous bell jar inverted?

Years ago in my life in cryogenic refrigeration systems I built a Show unit with difficult design parameters that required a 10" bell jar (Quartz/Borosilicate) to handle the vacuum and discharge pressures/temps we were working with. I used a 1/3hp refrigeration compressor for the cryogenic portion and my plate for keeping the weight down was made from 1/2" 7075-T6 plate I had anodized and then turned the seal portion to a surface finish of about 16 and the lip helped keep the jar on when atmosphere was present. I had to have the bell jar shortened and reground and bought a vacuum seal for it also. We used pure silicone vacuum grease around the shop for sealing and it worked fine. The unit could pull about .1 millitorr (3.9e-6 in.mg) and cycle back to atmosphere in about 4 minutes on that bell jar...cryogenically.

A system of your Whataburger size will take awhile to pump down even with a big compressor...1/2-1hp-something with a larger than 1/4" inlet. Our big units used 10hp 6 cyl. Carlyle's (06d) and our smallest used a 1/3hp Tecumseh's. Personally I wouldn't even consider a venturi system...your compressor may have a conniption fit and suffer a seizure...let alone the mind numbing noise generated.

Be sure your bell is in good condition and I would recommend a needle valve to vent the system...slowly. Dangerous implosion hazards otherwise. I don't know if anybody but old timers know what happens when you shoot a TV picture tube with a 22...similar attributes but 14mm quartz is sharp.

Sams Workshop Diary; Nice clean build, well done! Please be careful using off the shelf glass jars, they can become stressed over time and let go unexpectedly.


PJ

[Sam's Workshop Diary]

The maximum at the small glass that I used was -13,5psi

[Sam's Workshop Diary]

With no refrigerant in the system, is it necessary to oil the compressor?
If so, how?

Thanks.

kh

Yes it's necessary. From time to time you have to let the pump suck in a bit oil.

[Toolmaker51]

TM51, I am assuming you will be using the Humongous bell jar inverted?

Years ago in my life in cryogenic refrigeration systems I built a Show unit with difficult design parameters that required a 10" bell jar (Quartz/Borosilicate) to handle the vacuum and discharge pressures/temps we were working with. I used a 1/3hp refrigeration compressor for the cryogenic portion and my plate for keeping the weight down was made from 1/2" 7075-T6 plate I had anodized and then turned the seal portion to a surface finish of about 16 and the lip helped keep the jar on when atmosphere was present. I had to have the bell jar shortened and reground and bought a vacuum seal for it also. We used pure silicone vacuum grease around the shop for sealing and it worked fine. The unit could pull about .1 millitorr (3.9e-6 in.mg) and cycle back to atmosphere in about 4 minutes on that bell jar...cryogenically.

A system of your Whataburger size will take awhile to pump down even with a big compressor...1/2-1hp-something with a larger than 1/4" inlet. Our big units used 10hp 6 cyl. Carlyle's (06d) and our smallest used a 1/3hp Tecumseh's. Personally I wouldn't even consider a venturi system...your compressor may have a conniption fit and suffer a seizure...let alone the mind numbing noise generated.

Be sure your bell is in good condition and I would recommend a needle valve to vent the system...slowly. Dangerous implosion hazards otherwise. I don't know if anybody but old timers know what happens when you shoot a TV picture tube with a 22...similar attributes but 14mm quartz is sharp.

Sams Workshop Diary; Nice clean build, well done! Please be careful using off the shelf glass jars, they can become stressed over time and let go unexpectedly.


PJ

I'll incorporate your critical details, and before firing it up, contact you directly. Adding a needle valve for decompression will be first. I'm also thinking a racing style explosion blanket is worthwhile. Tried finding a big PVC or plastic culvert remnant, no luck so far. A couple inches clearance should do, either would vent implosion upwards.