Maybe the suction was to high what i would suggest is adding some foam say 10mm along the back wall that will be something ill be looking at now your always goin to get casualties with any extraction but the fewer the better thanks for the input im always looking on ways to improve
Well done, building something that does the job. I was thinking of bee vac building a while back. A couple of things I was considering.
Looking around for a smooth hose, the best I saw was from a pond supplies place, If the diameter was right it should fit into a standard 2 or 3m waste pipe of 32 or 40 mm from any diy shed, maybe a bit of tape to seal. That would then allow safe collection of many swarms about 4 metres or more high without step ladders or climbing.
The trick for a soft landing is to go from small cross section higher speed air (the pipe) to wider cross section lower speed air (the box). The "valve" in the side to reduce the air flow in the pipe should be in the box below the mesh. If it's in the box side, you still have full suction drawing bees into the floor with air from the pipe plus the side valve. If you reduce the air flow through the bottom mesh, the bees have a chance to recover the trauma of the pipe without being pinned to the floor.
If you wanted to pull the bees into the box with frames already in place, the bees emerge from the pipe at whatever velocity and then get a hard frame end to slow them down. I'd probably want the hose input in the lid. Entry via a cavity where the air flow slows and the opposite wall to the hose could have a foam or net baffle for a softer landing. From there bees should be able to crawl onto the frames.
An external cleaner sucking is versatile as long as there's a 240V outlet near. I was wondering if any of the rechargeable or 12v car vacs could produce enough air flow. Simpler to attach an existing package and easier to replace than sourcing separate components. Plus if you wanted to make more, no worries about certification because the electrical components are all packaged and certified as a cleaner.
The air flow would need to be enough to stop the bees flying out of the tube, the books say a bee flies around 14 or 15 mph so 20 mph or 9 metres per second is probably the minimum down the pipe. A flow of 9 m/s in a 30mm internal diameter tube I make about 6 litres per second. Not sure how that translates to "air watts" quoted for these machines which seems to be anything from 2.5 to 28.
Just an armchair design exercise at present.
