Positive improvement to my Pos pressure setup

[wopachop]

Using a 12v bilge blower to give a toyhauler fresh air. Its got a speed control and uses an automotive air filter to get rid of some dust. 

It was orginally 4" corrugated pipe. I thought it would flow better than flexible duct. 

While it might flow better....the noise was bad. It created an echo chamber. Ran it like that the last 3 years or so. Even on low speed the noise was loud.  

I used a cardboard box to test out a better approach. Now i have 3 air outlets instead of 1. The noise is considerably less. Whats awesome is outside too next to the blower the noise reduced a bunch. 

Lowes has filters for 5 bucks. I cut some in a circle and added to my ducts. Pretty happy with the results so far. Next will be incorporating a hepa filter. The auto filter i have now is a dry filter. I put an outerwears over it. Have blown it out a couple times. Its due for a replacement i would guess. Hard to estimate how many "miles" are on it. Wonder what the CFM of a regular F150 truck would be at 2500rpm? 

 

[kazuaki]

IS this supposed to pressurize the trailer to minimize the dust that comes in?  Noticeable difference?

 

[Jammer75]

IS this supposed to pressurize the trailer to minimize the dust that comes in?  Noticeable difference?

X2

 

[wopachop]

Yes that is definitely one of the goals. Positive cabin pressure to keep out the dust. The other goals are to cool the trailer and also supply nice fresh air. Its so dusty where my trailer is parked i never open any windows. Ive thought about sealing up the drip openings on the windows. That is a major entry point of hot/cold air and also dust. 

Been looking on amazon for a decent quality barometer. I recently installed a MaxxAir roof vent. I can tell its overpowering my intake bilge blower. I can actually hear the fan blades slipping on the air as a negative cabin pressure develops. Open the trailer door and that sound disappears instantly. I might end up powering my bilge blower from the MaxxAir fan. That way as the MaxxAir fan increases its speed the bilge blower will follow. With the overall goal to always have a positive cabin pressure. It would be easy if the MaxxAir fan would allow me to set the fan speed when using its built in thermostat. Tell the fan to only operate at 60% speed. I could then keep my bilge blower set at a speed higher than that.

As it sits now when im out of town and the MaxxAir Fan opens around 10am im pretty sure my trailer is in a negative pressure. I keep the bilge blower at around 50% speed when im gone. I dont like keeping it full blast 24/7 because its not needed. 

 

[wopachop]

Ive got another weird thing going. Maybe not worthy of its own thread.

Picture an insulated coffee cup. What if you could rig a trailer to act in the same way? 

The "attic" space of a toyhauler could pretend to be a coffee cup air barrier. The chemistry is different but the approach is the same. Its just a buffer of air. 

I tested this with poor results so far. It will get better though. My trailer has 3 roof vents. I played around with plugging up the center vent so it pulls from the outside 2.