Rainbow D4C SE Airflow Losses

[wyaple]

The first two measurements were easy to get, the last one (CFM at the nozzle) required me to build an airflow box. I think this pic should easily illustrate where and by how much CFM is lost in this machine. I think this is typical performance from this 24 year old cleaner.

From the base of the machine to the hose (stretched out straight), there is a loss of 80-60 = 20 CFM. From the hose to the nozzle, there is a loss of 60-42 = 18 CFM. The CFM lost through the pivot arm and housing assembly (in the power nozzle) is 4 CFM less than my D4C SE PE nozzle. Even with like new performing parts, you can easily hear air escaping when holding the power nozzle grip at certain angles.

Total airflow losses from the canister base to the power nozzle (held at a 45 degree angle to the floor) is 80-42 = 38 CFM or about 48% of the original airflow. Of course the Rainbow claim to fame is no decrease in airflow and I can say that measurements confirm that no matter if the basin has dirt or even water in it, the airflow stays very constant.

Last note: the rug plate opening is small (about 21 square inches) and the CFM density is well below average, about 1.95 CFM/Sq. In. With a CFM density that low, it would be difficult to get much deep down dirt if it weren't for the moderately aggressive brush roll with beater bars built in.

Bill

 

[pr-21]

The SE PE has a much better power nozzle, which deep cleans pretty well in my opinion. I am always amazed at how the water looks after cleaning my home.

PR-21
Bud

 

[floor-a-matic]

I only have experience with the Eureka-built R1024 & the R4375 PN; both do great job


 


The newest style from black E3 very good


 


I haven't tried the PN2 (SE/PE)

 

[wyaple]

I was surprised that...

this older (and less fancy) PN actually had a better CFM density than the PE (PN2) version. Since I now have both an SE and an SE PE, I noticed that the 1993 SE (with 80 CFM at the canister) has 42 CFM at the nozzle versus only 33 CFM for the PE. The SE PE's nozzle seems to have better agitation, but for picking up fine dust, I would argue that the older model would be better.

What I haven't measured yet is the older PN1 hooked up to the 1997 canister that has 87 CFM at the canister base. I might guess that 42 CFM might be raised to around 47 CFM and that would obviously crush the PN2's paltry 33 CFM.

Bill