Bee Vac using PVC pipe

[power napper]

Thinking about constructing my own bee vac and would like to know how small of a diameter the PVC pipe can be without losing usefullness.
Planning on using five foot sections of 3/4" PVC if it is sufficient.
Has anyone ever successfully used that small in diameter?
Thanks

[honeyman46408]

I use 1 1/4" CPVC it is for water and thinner than reg PVC or sch 40 pipe I can only suport two ten ft sections unless I can lay it on a limb or some suport.

[Ardilla]

The smaller the pipe diameter, the higher the linear velocity of the bees getting launched through the pipe. i.e. neglecting friction (which is significant w/ vacuums) a 170 cubic feet per minute rated shop vac would pull the bees at 330 feet/second (226 mph) through 1.25" pipe and 923 feet/second (629 mph)through 0.75" pipe. While these velocities are not achievable in reality, the 0.75" pipe will likely have velocities more than twice the 1.25" pipe.

At some point, the high air speeds will start ripping off the bees' wings and splatting them into the wall of the collection chamber (visualize a car windshield). I certainly don't know at what pipe diameters this would happen for a given vacuum - but I'm not sure I would use 0.75" pipe.

[ January 12, 2007, 02:33 PM: Message edited by: Ardilla ]

[honeyman46408]

"At some point, the high air speeds will start ripping off the bees' wings and splatting them into the wall of the collection chamber (visualize a car windshield"

That is why you construct a "port" in the vac to control the air flow or slow the air speed.

What you are looking for is just enough air flow that the bees cant fly aginst it. Is that clear as mud :confused:

[sierrabees]

My problem has not been cutting down on the air speed, it has been controling the leaks that limit the air speed. It seems like every winter the expansion/contraction of the wood in the bee-vac box is enough to create dozens of new air leaks and I never pick up the problem until I have to use the vac. This year I'm just going to duct tape everything except the control port instead of spending half a day putting in new caulking.