flexhose tradeoffs

[James Baker SD]

I am trying to connect a J/P combo machine to a duct port coming down from the ceiling that is pretty much dead center over it and a little behind it and 1.5 or 2 feet above it. The ducting at that point is 120mm hose adapter. I cannot keep the flexhose really short without physically moving the machine left/right several feet every time I switch modes and the dust collector ports flips over from side to side. I would rather not do that.

Medium length flexhose (good because it minimizes length of flex) requires a rather tight radius 90 degree elbow to the forced in the flex (bad). Longer length flexhose (bad) allows a much larger radius to the forced elbox (good).

Definitions: Long approx 10', Medium approx 7', short approx 5'. tight radius 1 or 1.5 R, larger radius 5 or 6 R.

I haven't really looked at the short option to see what kind of radius would be required (really don't want to move the machine for every changeover), but between the medium/tight, long/large which options would be best for not killing the airflow?

Thanks,
James

[David Kumm]

Can you put a 90 ell on the end of the flex and attach it - friction fit - to the port so it can be removed and put back when flipped over. The metal ell helps the flow. 6" hose dropping to 120 mm would help too. Dave

[Brian Brightwell]

Need some pictures. It would really help.

[James Baker SD]

Can you put a 90 ell on the end of the flex and attach it - friction fit - to the port so it can be removed and put back when flipped over. The metal ell helps the flow. 6" hose dropping to 120 mm would help too. Dave

Dave, I have a 120mm friction fit straight adapter that will allow disconnecting the flex during change over. I did not buy the 120mm elbow because it was more of a 90 right angle bend than any kind of radiused elbow and I did not want that sharp of the bend. I thought a larger radius elbow from the flex would be less damaging. I already have the 120mm hose adapter and flex, so I really don't want to change to 6" until I see that the dust collection is inadequate.

[James Baker SD]

Need some pictures. It would really help.
I guess I could take a photo of the ducting coming down from the ceiling and stopping at the hose adapter above the machine. Would that help? I haven't cut the flex to length yet, so I cannot show the medium option I described. 120mm flex is too expensive to make many trial cuts.

[Jim Neeley]

James,

You could install a Wye and pipe one side for the J setup and the other for the P. Install a blast gate at the end of each of the pipes and a short run of flex to the tool. A quick=release on the end of each hose and the j/p duct and the swapover will be quick.

Jim

[David Kumm]

Dave, I have a 120mm friction fit straight adapter that will allow disconnecting the flex during change over. I did not buy the 120mm elbow because it was more of a 90 right angle bend than any kind of radiused elbow and I did not want that sharp of the bend. I thought a larger radius elbow from the flex would be less damaging. I already have the 120mm hose adapter and flex, so I really don't want to change to 6" until I see that the dust collection is inadequate.

You could still use a 5" ell and put some duct tape on the 120mm fitting so it just slips into it. Dave

[Jamie Buxton]

I did pretty much what you're contemplating, but used 6" flex hose, necked down right at the A3-31. 6" has 60% more cross-sectional area than 120 mm, which should help make up for the turbulence in the flex, and the required bends. The flex is about seven feet long. The air flows from the top of the flex through 6" round metal duct about five feet to a 2 hp Woodsucker cyclone. The whole system works fine.

[James Baker SD]

Several replies have suggested that I increase the diameter of the flex until I get closer to the port on the J/P. I initially resisted because I had the 120mm hose adapter installed already. However, it dawned on me that I must have chosen Nordfab for a reason.

So, the 120mm hose adapter is 7" on its large end and clamped to a 7" blast gate. I can remove the hose adapter and connect an existing (surplus from when I connected one machine at a time) length of 7" flex to the blast gate to get close to the port (it is 10' if I don't shorten it). The hose adapter clamps to the 7" flex and I use just 4" or 5" of 120mm hose as a connector from the the hose adapter to the friction fit 120mm connector that goes on the J/P. Most of 120mm flex will be on the outside surfaces of the two pieces it is joining, so it will be really short.

Does this sound like a plan?

James

[David Kumm]

I'd try it. If it doesn't work, send me all your Nordfab stuff. Dave