Black Box Vac Source

[sbd1]

last 5 pics

[pkirby]

I noticed the Lighthouse vac motors require a 1/4" hole (per motor) to allow leakage for proper cooling. Do you guys put (2) 1/4" holes in each chamber of the vac motors or do you put (4) holes in the plenum?

Thanks,
Paul

PS. I just ordered (4) of the LH 7123

[jim_vv]

Greetings, Paul

I used a 1/2" ball valve in the manifold to allow bleed air into the system for the times when I cut material that allows me to get a perfect seal. With a perfect seal, the vacuum drops 1 in.Hg when the bleed air valve is fully opened. I installed a sintered bronze muffler on the valve to help with noise and to ensure that nothing gets sucked in. Most of the time I allow the motors to breathe a little by leaving a gap in the vacuum mask around the part that I am holding. I like the valve idea because, depending upon what I am holding, it gives me the option to leave it closed, open it part way, or open it all the way.

Kind regards,

JIM

[pkirby]

Thanks Jim, I'll try that approach. Where did you get the bronze muffler?

Thanks,
Paul

[jim_vv]

Greetings, Paul

Grainger sells them in various sizes. I used a 1/2" NPT muffler.

Kind regards,

JIM

[sbd1]

Paul: Good question, I didn't know about that.

Jim: That looks like a good idea.

I believe there's probably enough leakage in my system to equal the flow through a 1/4" hole per motor. Guess I'll know if one of the motors burns out. I do have a separate 2" valve that I open when starting & stopping the motors though to reduce the load at startup.

[pkirby]

Jim,
Thanks for the link.

Daren,
The 1/4" hole per motor is mainly for cooling the vac. I always have wondered if I had enough leakage in my system so that I wouldn't need the seperate holes. I wonder if anybody has figured out how much leakage there is by gauging how strong the vacuum reading is? To better explain... If you have 10"hg of vac and that is the max this motor is capable of, then there would be 0 leakage. But if you're reading 9"hg of vac, then that equates to "blank" leakage? (I'm not smart enough to figure that out)

[jim_vv]

Greetings,

I used a 1/2" valve because the area of a 1/2" circle is the same as the sum of the area of four 1/4" circles. In may case, I read 11 in/Hg with all motors running, all the zones valves closed, and the with the bleeder valve closed. When I open the bleeder valve all the way I read 10 in/Hg. If my part/sheet hold down is leaking and I read 10 in/Hg then I don't open the valve because I figure the motors are getting a little air which appears to be a loss of 1 in/Hg. Not very scientific, but it seems to work for me.

Kind regards,

JIM

[pkirby]

Good idea Jim. It may not be scientific, but it seems perfectly logical to me

[larry_k]

Hi ,I would like to make my first vac table. I love the black box that has been made. can any one send me the files. thanks alot larry
kilian55@comcast.net