CNC Vacuum Pump Placement
Placing the pump at a distance, or even outside, helps keep the noise down. October 3, 2007
Question
We are looking at moving into a new building, and I would like to put my vacuum pumps outside. I am in the Pacific Northwest, and currently have both pumps in the shop, where it is loud and hot! In the summer we duct the exhaust outside, and use it to heat the shop in the winter. But I am wondering what the pros and cons are for this situation. Anybody got theirs outside? Also, is there a rule of thumb for distance from vacuum pump to router table? We have a 5x12 with a 20 HP and a 4x8 with a 10 HP. Currently each pump is just a few feet away from its table. I appreciate any help!
Forum Responses
(CNC Forum)
From contributor A:
The farther away the pump from the router, the better, just like your air compressor. If I were you, I'd put the pumps and air compressor in a separate mechanical room to keep the noise and heat away.
From contributor R:
We have always kept our pumps outside. Enclosed and sheltered, of course. Dealing with the dust and noise of routing parts is enough. I would not want that vacuum pump right next to me. Place your router as close to an outside wall as possible and minimize the number of ells the vacuum pipe needs to make. Velocity will drop from distance and restrictions. Someone out here may be able to give you a better answer...
Now is a good time to install a secondary filter at the machine. And make cleaning the filter a weekly scheduled task.
I'm not sure of what you were using as exhaust from the pump for heating purposes, but keep in mind that the exhaust out of the separator may be somewhat toxic. If you do set your pumps outside, and enclose them, ensure you provide adequate ventilation and install exhaust fans. Idle air around the pumps in an enclosed environment is not enough to keep them cool. You may have issues with HAT switches tripping or the overload releasing.
Also, if you have more than one pump, you may want to install bypass valves that will allow all routers to operate when a pump goes down or is being serviced.
From contributor L:
We placed our unit, which is a 40hp Travini, about 55 feet from the router and vent it outside with no vacuum loss. Yes, there is noise, but less than the router and most of our other equipment in the shop. I researched putting it outside also, but every pump manufacturer cautioned me because low temperatures, even in the low 40's, create a lot of stress due to oil viscosity. We're located in western Washington but we do have the temp drop down to freezing on occasions. You're welcome to visit if you would like.
From contributor D:
A good length run of 3-4" vacuum line provides a buffer of vacuum when through cutting, etc. Avoid sharp 90 degree bends, as this can affect CFM by causing more turbulence and resistance. We have our pump on an 80 foot run of 3" schedule 40 PVC. It can slow down how quickly vacuum releases when pump is turned off due to the vacuum "stored" in the line.
From contributor C:
Oh boy! Another thing I didn't think about when buying my CNC machine. No one told me about putting my vacuum pump away from my machine. It's right next to it. I spent a small fortune in electrical just to get to its current spot. I would hate to think I need to move it. My PVC setup came with sharp 90's. Should I re-work the duct work with 45's?
From contributor J:
PVC electrical conduit works well for plumbing vacuum pumps since it has nice swept bends, thus helping eliminate those dreaded 90 degree elbows. A lot of vacuum pumps now, like Traviani, use synthetic oil, so viscosity to temperature is a non-issue.
The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).
Comment from contributor A:
We put our pumps on our Biesse Rover about 40 feet from the table. I sincerely regret the vacuum loss. We have two 20HP on a 4x8 sheet, but cutting plywood we need every pound we can get. I saw a similar unit with the pumps in the standard position next to the machine and the difference was night and day. Some people will say it's a closed system - don't worry. But in reality, vacuum on a CNC table is always moving and you lose with every foot.
