Legit vacuum pumps

General Composites Discussions Equipment Talk
#1

I’m thinking about upgrading to a legit 2 stage rotary vane continuous vacuum pump, but have a few questions before I do.

I currently use a 6 CFM Robinair. It’s loud, exhausts oil mist, and I get worried about it running for long periods of time, as I don’t think it is designed for continuous use.

I work on 2 to 3 molds at a time, in various stages and slowly add them to the system one by one while the pump is running. By the end of the day, I’ve got 5-7 going at once, all still at full vacuum. I have a timer that lets it run for a few hours and by morning, everything is cured and ready to pull (and I start the whole process over again).

I do notice that as I add another bag to the system, pressure drops on everything else for a minute or two, and this has me concerned.

I’m thinking about hiring another guy or two to help me set up more bags, which is why I’m considering a larger and better pump. We’ve got a couple contracts in the works that could mean quite a big increase in our production schedule. Most of the pumps I’m looking at run for $3-4k, seem like they are pretty quiet, some don’t emit any exhaust. All big selling points. Most of them are 40-60 CFM, which would obviously be a huge improvement over my current setup.

Since the 6 CFM pump is the highest rated pump I’ve used, I’m not really sure what to expect at 40-60 CFM. Rapid suction on each bag and probably the need for regulators.

My biggest questions are:

  1. Will I notice pressure loss as I add more bags to the system?

  2. What are features I should be looking for in these types of pumps?

  3. Trusted brands? It looks like Edwards is pretty solid from what I’ve been reading.

  4. Is it really continuous running with no issues?

  5. Are they really quiet? Or still loud, but quieter than lower end models?

  6. Anything else of note?

Thanks

#2

My largest pump is a Leybold 16A and is whisper quiet and can run continuously without concern but it does require the high end lab type vacuum connectors . It also has a muffler/de-mister for the oil control.
My other three pumps are the 6cfm Robinairs I use for roughing. And then My smallest pump is an old Welch that I often run overnight due to its low utility use.

#3

I can’t recommend getting a Vacmobile enough. They are not the cheapest pumps on the market but you get an entire system; pump, manifold, resin trap/degassing chamber and a handy trolley plus great after sales support. I’m pretty sure that they could modify a system to give you a turn-key vacuum system. Check them out at http://www.vacmobiles.com/

I have had a multiple parts infusing off one pump many times. They are nice and quiet and very compact and I had one run for about 4 days solid over a long weekend. I’m just sad that I had to leave it at the old job and at the new one we have some crappy refrigeration pump with a mashed up bunch of tubes.

#4

We have one of those vacmobile setups and it’s pretty nice with a degas chamber and cart. Strong and quiet.

As for pressure loss… do you have a tank? If you have a vacuum chamber it helps to keep the pressure more stable if you have leaks or if you disconnect/connect stuff. Also with a tank your pump can be on a switch and only run when the vac drops. We have a large pump, don’t know the type but I can check if you like. It’s large high CFM and runs across the shop to the clean room and still pulls 29" in the clean room.

#5

Probably more than I need, but I’ll inquire.

I don’t, but I could easily add one. How big of a tank are we talking? Anything else I should consider with it?

I’d like to know what you use, and the specs of it. How many connections can you run off it at once? Your setup sounds very similar to mine. I have a dedicated room for compressor, pump, and dust collector and run an airline into my layup working space. Much, much better than at my old space when I had the pump right next to where I worked. Loud, dirty, oil everywhere, loud…

#6

Yah we have a room for pump and compressor as well. Had to vent it as it was getting super hot in there… like over 100 degrees

I’ll check the pump label next time I walk by. It’s large though, with a big tank, not sure but 50+ gallons. Bigger doesn’t hurt. It adds more resivour to stabalize and spikes in loss. I guess sorta like a capacitor.

As for the number of lines off it. Probably like 40 or so I’d say. They used plastic tube to carry the vacuum which, I don’t like. The system seems to work well as i just got a high accuracy guage and it shows over 29" in the clean room.

The ovens run off individual pumps for each oven, a must if you’re doing anything costly. Then you don’t have to worry about some random bag or fitting leaking away during a cure cycle.

#7

You can look for Adixen, Edwards, Leybold, Pfeiffer, Varian, Busch and Welch. That are some high end vacuum brands. If you spend money on pump go for a big one (+ 20 cfm) so you have enough cfm for in the future. Maybe a option to use 2 smaller pumps because that has some benefits. New is a waste of money, go for a good secondhand (not to old and look at the history use) or a refurbished one. I can recommend a air tank / chamber. The size I can’t tell, not to big and not to small (between 10 and 30 gallon or so). Also use some valves to arrange the vacuum bags seperately. Also go for a digital vacuum controller. No need to run the pump continuous when the vacuum is oke.