Duct selector

[thelxbloke]

Hi all,

 

In my infinite wisdom I have come up with an idea with only the makings of ideas on how to create it.

 

What I want to do:

 

Have one smoke machine - ZR33 already in the hire list

Feed two different places - fine you may think but here's the hard bit

I want to choose which pipe it goes down by means of some kind of valve system.

 

Oh and it needs to be as low budget as possible (of course!) so 4" ducting will be used for cheapness and availability.

 

My ideas so far:

 

A box - 1 in 2 out with some kind of shutter in between.

http://redeyeps.com/Smoke%20swapper/box.JPG

 

Shutters:

 

Either this

 

---------------------------------------------------------------(rail)

| |

@-------------------| | --------------------------@ (motor, winding, cable, panel, cable winding, motor)

| |

----------------------------------------------------------------(rail)

 

Or a motorised disk with one two holes in it.

 

The main problems will be:

 

Control - I'm thinking analogue here or DMX if we can get it at the right price (was thinking about this DMX motor driver)

Monitoring - Where the heck the shutter is, if it's the disk, how fast, that kind of thing.

 

Anyways, massive thanks in advance and I hope together we can come up with some good solutions :blink:

[robloxley]

If you can't do it manually (ie. by switching over ducting hose connections as needed) then surely it's easiest and cheapest to hire a 2nd smoke machine?? If you really want to go down this route then dust extraction blast gates might be useful for the 'valves', with a servo motor to open/close them; unless you really need DMX control Id avoid it, as it'll just add to the cost & complexity.

[GridGirl]

I've seen projector blackout devices made out of CD-ROM drives - if you built it right you could use them as your shutters. You'd probably only have "open" or "closed" options, but it would save the monitoring problem and be a fairly simple solution!

[paulears]

and many smoke machines don't have the guts to put out enough to do much more than trickle out of the end of a length of 4" - I'm guessing that the ribbed internal surface doesn't exactly assist the passage of the smoke.

[willdean]

What about putting a fan (like a PC cooling fan) at the start of each of the outlet pipes, and then only turn on the one which you want. This would lower the pressure in the plenum to the extent that smoke shouldn't come out of the wrong pipe. (I'd hope!)

 

I'm sure it would need some experementation, but it would be an awful lot easier to construct than something involving mechanical valve actuation.

[Seano]

What about putting a fan (like a PC cooling fan) at the start of each of the outlet pipes, and then only turn on the one which you want.

This strikes me as the way forward, but rather than bodging it with just any old fan, why not use a Y-split and a couple of proper inline duct fans?

[robert morley]

even with the fan me thinks that a small amount may get out of the one you are not using unless you can put the other in to reverse. Or use the fan along with the shutter idea maybe. :)

but you are right about the smoke traveling along any distance more than what the machine can spit out, I would use a fan to give it more omphh but nothing to big or it may "water down" the smoke density.

[pete LD]

I have tried ducting smoke down 4" pipe and its sh1t. you dont get much out the end. I am assuming you will be going some distance? my suggestion would be: instead of hiring a Zr33 and cutting the out put by putting it down pipe hire 2 Zr12s and put them in the 2 points you want smoke! simple cheep and DMX!

hth

pete

[dbuckley]

You're asking the right question but in altogether the wrong place.

 

You need to find a forum where the air conditioning types hang out; they use diverter valves of the sort you need on air handling units, you can see the bits in the usual catalogs, but you could do with some advice, and also save dosh over just getting bits out of the RS cat.

[willdean]

even with the fan me thinks that a small amount may get out of the one you are not using unless you can put the other in to reverse.

 

I don't think that would happen, provided the smoke-machine side of the box was reasonably well sealed onto the machine.

 

The fan exhausting the box into the active outlet pipe will then cause (diluting) air to be drawn in through the unused pipe, where it will be mixed with the smoke from the smoke machine. The box itself will be below atmospheric pressure, so shouldn't leak smoke in any direction.

 

Not that I think it's a good idea - I'm firmly in the 'use two machines' camp.

[thelxbloke]

I might have a play with the fan idea, seems the best bugetry idea.

 

Chears guys (and gals)

 

Steve

[Ynot]

.... provided the smoke-machine side of the box was reasonably well sealed onto the machine.

If I read this right, sealing the pipe to the smoke machine is most DEFINITELY the wrong idea. That's a common mistake made by newbie fog users, under the mis-understanding of how the machines actually work - there MUST be air immediately outside the nozzle or the fog will simply f@rt instead of gush. :) That could explain why some piped smoke attempts fail to produce much of anything!

Not that I think it's a good idea - I'm firmly in the 'use two machines' camp.

Same here - trying to build something that will accomplish the aims is going to be costly in time and probably money in the long run. MUCH simpler and easier to operate 2 smaller machines.

TD

[3guk]

Just get a massivly high airflow fan or something, and have one in each duct.

 

You turn the fan on in the duct you want, no doubt you'll get a little bit of smoke comming out of the other but not much.

[Ynot]

Just get a massivly high airflow fan or something, and have one in each duct.

Trouble with that option is the smoke gets spread thinly, and comes out more haze than smoke!!

 

Use a second fogger!

:) ;)

[thelxbloke]

... sealing the pipe ... wrong

Not that I think it's a good idea - I'm firmly in the 'use two machines' camp.

Same here - trying to build something that will accomplish the aims is going to be costly in time and probably money in the long run. MUCH simpler and easier to operate 2 smaller machines.

TD

 

I know about the sealing the pipe thing, I tend to read manufacturers guidelines, they don't invest god knows how much in research, product development and testing to help you use things badly :)

 

As for hiring two machine being cheaper than me doing this, I doubt it. at approx £60 perweek for another smoker and about £20 to make a basic box (might use an old cool box then I can adapt it for low smoke if I want to -only just thought of that one!), we'll be buying ducting whether we do this or not as we can't fit a zr33 under our drum riser (this is for a festival btw).

 

I'll have a play and see what I can come up with.

 

Chears all.

 

Steve