Is your suction killing your airflow

[vegassucks]

Suction and airflow, understanding the difference is the key to understanding 33% of what you need to clean floors. If your vacuum has too much suction you might actually be restricting your airflow.

I tested this theory with my Miele S8 by using the full bag gauge as a tool. As you restrict airflow the full bag gauge will start moving towards red until there is little to no air full and the gauge is completely red.

I first set my Miele S8 power to high, you would think more suction must mean more airflow right? Well actually no. As I turn the power to high the power head actually starts to create such a tight seal to the carpet that the bag gauge actually moves about 1/3 to red even thou my my vacuum bag is empty, I am actually starting to restrict airflow with suction.

Each power level I go down the red portion of the gauge is reduced meaning more airflow until I Set it on the thick pile rugs and runner settings which is just above upholstery and 4 down from the full power or hard flooring.

So I am thinking this cannot be right, How can this vacuum still clean? So I throw a large pile of heavy cereal down on the carpet and the Miele sucks it up 1st pass no problem. Additionally at this setting the bag gauge show a new or fairly empty bag which is accurate.

I hope this helps some of you understand suction vs airflow a little better, it sure helped me.

 

[gsheen]

Suction and Airflow are competing forces in vacuum, as one goes up the other goes down, Remember that airflow or cfm is also greatly reduced by friction, IE thats why you will always have more airflow at the end of a 50mm hose compared t a 32mm standard vacuum hose.

Vacuuming is simply using pneumatic's to move something (dirt and dust ) from one point ( your carpet ) to another ( dust bag or bin)

Too much suction and you wont be able to remove any dirt,when your vacuum reads maximum suction, it isn't moving any dirt , just suspending it, as their is no airflow to be able to move it along the hose,

Massive airflow will move light articles with ease but wont be able to lift heavier articles.

Thats why direct air vacuums work so well, because they have the brush to get the dirt out of the carpet and lift it into the airflow.

The trick is finding the sweet spot, This is done with a flow charts to determin were the suction and airflow meet at their respective highest points, This is what vacuum engineers strive to achieve.

Some massive truck mount carpet cleaning systems like the ones we have you can actually set the airflow and lift for different cleaning situations but adjusting the pully's between the motor and vacuum pump. you also have different nozzles for different styles of carpets some allowing more lift some more airflow

 

[dysonman1]

The full bag indicator on the Miele is operated by pressure. That's why it moves to 'red' when you put your hand over the end of the hose. A TRUE measure is one that uses the pressure difference between the clean side of the bag (the compartment) and the inside of the bag. Electrolux perfected it, and no one has really copied Electrolux's method. That's why a Lux doesn't "pop open" when you put your hand over the end of the hose. The simple pressure reader, used on most vacuums (even tacony's) is a cheap, inexpensive way of trying to let you know when the bag is full. It has nothing to do with airflow. Only the build up of pressure (which we call "lift").

 

[vegassucks]

Good video on suction vs airflow.

 

[vegassucks]

Dysonman 1

Dysonman1, maybe you should contact Miele and let them know their manual is wrong.