I need help/ i have a question about a Laguna PFlux 3 connection

[Jonny]

I just bought the laguna p|flux 3 and i will be running all my pipe on Monday, but it came with a 8" by 4" 3 port connector and I was wondering if i could remove it and just route an 8" down to 6" reducer and connect with that or do I have to connect to one of the 4" ports? i feel like i read somewhere that you can use 2 of the 4" ports and then leave one open. But i am VERY new to all of this and I dont want to break my dust collector by hooking up a single 8" connection if it is not meant to handle that, please help. and thank you!!

 

[Jonny]

this is the connection i am talking about, can i just remove it and connect an 8" to 6" reducer and run my pipes?

i know the image is a CFlux, but it looks the same

[krtwood]

Yes you can just reduce from the 8" to 6".  You don't harm a dust collector by restricting the airflow.  It's counter-intuitive but the more restricted it is the less power it draws.  In fact if you just completely close off the inlet that is when it will draw the least power as it's not doing much work.

[Jonny]

2 hours ago, krtwood said:

Yes you can just reduce from the 8" to 6".  You don't harm a dust collector by restricting the airflow.  It's counter-intuitive but the more restricted it is the less power it draws.  In fact if you just completely close off the inlet that is when it will draw the least power as it's not doing much work.

so then i'm good to remove that 8" piece with the three 4" ports and just add an 8" reducer and the 6" pipe to it?

thank you krtwood

 

[Mark J]

I confess I don't understand the science of this issue.   Look at it this way.  My P-Flux 3 came with the same 3x4"  reducer.  It also came with rubber plugs for two of the three ports.  So I figure I'm supposed to be able to run the machine with only 1 port open.  I have had the machine a couple of years and run with one or two ports closed.  By the way even if all 3 of the 4" ports are open the total area is 25% less than the 8" openning.

[Chestnut]

23 hours ago, Mark J said:

confess I don't understand the science of this issue. 

Air has weight. The energy consumed is the motor moving that air. The more air moved, the more power gets used to move a larger weight of air.

[Mark J]

OK, got that. 

But air flows because of a negative pressure gradient.  Does a motor and impeller create greater negative pressure if running at a lower load?  In which case running with only one open port would produce the greatest air flow in that port.  If so how significant is the difference.  

And then there's this, the cyclone needs a reasonable amount of air flow to do it's thing.  Is one port enough of an air inlet?

So I'm never sure of the optimum set up or how much it matters.  

[Chestnut]

11 minutes ago, Mark J said:

OK, got that. 

But air flows because of a negative pressure gradient.  Does a motor and impeller create greater negative pressure if running at a lower load?  In which case running with only one open port would produce the greatest air flow in that port.  If so how significant is the difference. 

Negative pressure is a frame of reference, does the impeller create negative pressure or positive pressure? It more accurately creates negative pressure before the impeller and positive pressure after. In impeller systems pressure is relative to RPM and as induction motors spin at the same RPM theoretically the pressure is static, but this is incredibly complicated and works in theory but not in practice. The difference can be significant. In practice as airflow increases static suction decreases where the highest static pressure is at 0 CFM of flow. Dust collectors are sized to work best with 4-6" ports. Smaller and there will be too much pressure loss and larger will result in too little air velocity.

23 minutes ago, Mark J said:

And then there's this, the cyclone needs a reasonable amount of air flow to do it's thing.  Is one port enough of an air inlet?

No probably not. This depends on particle size as well though. Smaller parties need more air to be removed than larger particles.

26 minutes ago, Mark J said:

So I'm never sure of the optimum set up or how much it matters.  

For a 3hp cyclone collector I'd say 2 4" ports open at all times is a minimum. A maximum would be 3 4" ports. This is again complicated. This depends on your frame of reference. Are you asking optimism for cyclone separation? Optimum collection at the end of the 1 port? Optimum velocity in a vertical pipe?

[Mark J]

So it's complicated.  I think your two port suggestion is a good one, but a person can be comfortable the DC isn't going to burn up pulling through one of the 4" ports, or through the 8" port.

[Chestnut]

4 minutes ago, Mark J said:

So it's complicated.  I think your two port suggestion is a good one, but a person can be comfortable the DC isn't going to burn up pulling through one of the 4" ports, or through the 8" port.

The DC will burn up in the opposite situation when there is too much air moving through the collector. Smaller vacuums like shop vacs would burn up in the past when the inlet was plugged because most of the motors were cooled by the air that moved through the system. If the inlet or filter was plugged there wouldn't be any cooling air, it did not burn up as a result of being overloaded.  Smaller vacuums like shop vacs also operate slightly differently, though they also will have a lower power draw when the inlet is plugged.

Large collectors have induction motors that are cooled independently from the flow through the system. Mine has a motor that has it's own fan that keeps the motor cool. It is also important to note that there is a LARGE start up load on these systems so it is always better to turn them on and leave them run for hours compared to turning them on every 5 min to do a quick job. My manual says you shouldn't start the system more than 4 times per hour.

[Coop]

Good info Nut. Did not know that about the on/off. Thanks

[DocTN]

So back to the original question on the reducer...  I have the same system with 3x4" inlet.  Where in the world do I find a 8"-6" reducer that will fit on the inlet opening???

[BonPacific]

On 12/29/2021 at 6:05 PM, DocTN said:

So back to the original question on the reducer...  I have the same system with 3x4" inlet.  Where in the world do I find a 8"-6" reducer that will fit on the inlet opening???

Home Depot has 8" to 6" adapters in both metal and PVC. I think the PVC are harder to find in stock, but either way check what the internal and external diameters of your port are and take a ruler or caliper with you to the store. Aluminum ducting tape is also quite good at spanning some minor size differences.