Refrigerator vacuum pump

General Composites Discussions Equipment Talk
#2

i ve had 3 refrigerator pumps, all of them run constantly without any rewiring from me. only the smallest one has some sort of thermal relay, and if you pull it out of the plug, you have to wait about 30 secs to 1 minute before it will start again.

fridge pumps have a special oil for lubrication, which is resistant to low temps, but since we arent using them for that anymore, any oil will do (i put some spare GReddy oils in mine lol)

these pumps have a suck line, and a vomit line, which expells the air they suck. after a while, oil may be spat out of there, in which case you can either put a cup there and collect it, and later feed it to the suck line, or put new oil (make it suck it lol)sluuurrp.

#3

You might find this amusing…

…I’ve been using a fridge pump for 5+ years now, both as an air compressor (pressure out going to a regulator and storage tank), and as a vacuum pump. Never both at once, mind you…always allow it to suck free air when making pressure, and never make it compress air while sucking!

…Anyhow, after 5+ years of loyal service, my pump’s been getting hotter and hotter lately, and the thermal cutout has started to kick in, so I figure “Hey, I haven’t lubed this in ages, let’s try that”

So I stick the suction line in a jug of Castrol 5W-30 for a second. Slurp goes the oil, suddenly I’ve got no more suction.

Yup, I overfilled it with too much oil. Even after draining it, I only got one more infusion out of the thing, now it’s totally seized.

Moral of the story? None, really. Fridge pumps aren’t intended for what we’re doing, and they will die sooner or later, and no amount of 5W-30 can stop it.

And yes, I realise that these are supposed to get a very low-viscosity, light mineral oil. I usually use that…just…didn’t for some reason this time.

#4

Do these fridge pumps smoke/burn oil?

Thanks guys!

Aga says " TAKE THAT SUCKA!"

#5

IF you run 'em really hot (and that’s like, too hot to keep your hand on the thing), you will notice a wisp of smoke coming out of the high pressure end after you turn the pump off.

#6

Excellent! This is all good news :cool:

#7

I use fridge pump as vacuum pump. Im able to pul 0,95 vacuum quickly (I have a vacuum reservoir/resin trap made from fire extiguisher about 3liter). Its working quite good. Problem is, that at 0,95 it stops pulling, it is working but with strange noise and there is no movement on gauge. When you shut it off and turn on same thing. There must be a drop to about 0,8 , that the pump is again able to start pulling to 0,95. Its quite good solution for start working with vacuum tech but I hope I will buy profi pump ass soon as possible.

For the wiring… Post picture of your pump and wiring board. I changed wires on mine, so I dont use thermal switch.

#8

hahaha! mine has GReddy 10-60 in it!

#9

I hope it has great bearing to journal clearance! lol

#10

sure does, it was built for use with high vacuum pressures and nos!

#11

I was thinking of bolting a Vortex Blower up to mine:D … maybe a 150hp shot of NOS.

#12

Fan-- If these are positive displacement vacuum pumps it seems like running too much oil through them could cause hydraulic lock. Any idea if that’s what happened?

Speaking of inexpensive pumps, have any of you guys tried professional vacuum pumps designed for air conditioner servicing? These seem to pull enough vacuum and are readily available second hand. Question is can they be run for hours on end as our composites cure?

Nic

#13

Nic - AC vacuum pumps would be perfect for this. At my job, we run them for days at a time to completely evacuate and vaporize any contaminants inside refrigeration coils. Just so long as the oil is kept within the operating zones, you won’t have any trouble.

I just got a new (old) fridge pump, and this time I put an Air Logic vacuum switch onto it to keep the pump from running unnecessarily.

#14

where can i get one of those? (for 220v)

#15

http://www.veneersupplies.com/default.php?cPath=60_36

It’s listed as “Vacuum Controller” on this site. Allegedly, it will work for 15A loads at 240 volts, and if that isn’t enough for you, there is a relay directly beneath the controller that would work for up to 30 amp loads.

All I needed was the controller. Cheers!

#16

I’ve been using a Medo linear piston pump for the past year after my frig pump burned up. Only 1 moving part & no oil needed. Works great for the small parts I’ve been molding but I’ll give it the test this winter when I build a front splitter for my Vette.

http://www.medousa.com/en/product/product_spec.asp?ID=39&prd_ln=lpvp

#17

You bolt an electric motor onto that pump Joe? How much did you have to pay for it all? Thanks

#18

I use 125W fridge compressor. Just use suction side as vacuum source. I’m able to pull 28,8" (I’m 1000feet under sea level ) with it! Theoretical maximum for my level is 28,9", so the pump is really strong. I had also few 90W pumps but they are not so strong and they stop working at smaller vacuum. In the future I want to try bigger fridge compressor. So its possible to use fridge compressor as vacuum pump for composite production. BUT there will be overheating issue if you want to run it for a long period of time. I use it for infusion, pull max vacuum, than clamp it off and shut down.

#19

Nope. It doesn’t use a motor. It doesn’t rotate to create vacuum. The only moving part is the piston that osculates back and forth magnetically.

I paid about $100 for a NOS VP0660 unit but they are sort of expensive for a new one. A new one is listed on ebay now for $79.00

#20

my friend who’s an air -con specialist says this pump:

http://www.fibermax.eu/shop/images/vaccum-set.jpg

is a pump thats used by technicians to create vacuum in air con systems , and costs 55 euros to buy…

#21

Aga…buddy, sort a long time no hear from you.

That looks like a good ac vac pump. I have a Robinair ac vac pump that works great. It is noisy and produces oily smoke.

I was very interested in Joe’s pump idea with the magnetic piston… should be next to silent operation with zero smoke output… he said it will pull around 25hg and operate for 24hrs at a time with no problem. At 25hg it probably isn’t the best thing for vacuum infusions, but for what i want it will work great. I’m all for buying one since it is less than $200. That’s about my spending limit for a pump.

This guy i used to work with had an ancient old-school ac vacuum pump. It ran via a 110v motor pullied to the pump portion, it pulled 50 microns. We hooked up a 3/8 i.d. polyethelene hose to it and man that pump would run forever and could suck a socker ball thru a garden hose. Very quiet operation too. To this day that is the only pump i have ever seen of it’s kind.