I have noticed that most of the newest vacuums manufacturers are always pushing how powerful the motor is, and how deep the suction is. The deeper the suction, the larger amounts of dirt the vacuum is supposed to pick up. For instance, the bowling ball in the Oreck ads. In order to obtain extreme low pressures, the motor is spun faster. This results in extremely noisy motors.
I don't think that a higher pressure vacuum is as effective as one that moved larger VOUMES of air. The problem is that most vacuums are not really designed to move large volumes of air, their hoses are relatively small, and the impellers on the motor are small too.
Why do I think this? Well, let's think about a typical floor nozzle in a vacuum, and what happens when a piece of dirt encounters it. Saying that the vacuum moves dirt is sort of a misnomer. What actually happens is that the vacuum removes the air in front a dirt particle, and the ambient air pressure beind the dirt then pushes it up the hose. If the air is removed faster, as in the case of a strong vacuum, the dirt particle moves faster up the hose, and a larger dirt particles can be picked up due to the lower pressure.
Now the issue comes when you want to pick up LOTS of dirt particles, which, if I'm not mistaken, is what the goal is when cleaning the house with a vacuum cleaner. In this case, one needs to not necessarily achieve a deeper vacuum to move the dirt faster, but it needs to swallow up lots of air that's ahead of all those dirt particles.
My own experience seems to be that high-volume vacuum cleaners seem to perform better than the high pressure ones. For instance, I have a little Hoover vacuum I use for cleaning electronics. It's got an extremely powerful motor, but a tiny fan and hose. It will pick up some pretty big stuff, but if one were to connect it up to a floor attachment, it's performance is dissapointing. The polar opposite of this is one of those big central vacuum installed in a machine shop. It's got a big fan in it that's comparatively slow turning. Although it would not swallow a bowling ball, It can swallow enormous amounts of sawdust and other shop dirt.
I would be interested in experimenting with various vacuum designs to see which actually picks up more or less volumes of dirt. The classic Electrolux model 30 (XXX) vacuum is famous for being a quiet, but effective vacuum. I imagine this is because it swallows up large volumes of air with a big blower. This would be in comparason to some of those little screamers avaliable nowadays. To perform an experiment, there will need to be many factors precisely controlled. The size and amount of dirt particles, and the density of their scattering will need to be closely monitored across the testing surface. I will then need to obtain a variety of vacuums of various shapes and sizes. The maximum negative pressure, and the CFM moved by each vacuum will need to be measured precisely. When the dirt pickup stage begins, each vacuum will need to have the same nozzle installed, and the nozzle will need to be pushed at the same time and distance for each vacuum. To measure the amount of dirt picked up, the bags will all need to be measured before and after the "dirt run" to see how much is actually in them.
It sounds like a worty endeavour, and it could dispel a lot of myths in the advertising of vaccuum cleaners that an extremely low pressure cleans better than a high volume of air moved....Then again, this is a lot of work for a simple answer, and my results are probably not going to be published anywhere significant...Maybe I could give this challenge to a high school physics class, or, the best thing is to ask vacuum cleaner experts, like the ones here....what do you think? Is it high volume of high negative pressure that cleans the best?
I don't think that a higher pressure vacuum is as effective as one that moved larger VOUMES of air. The problem is that most vacuums are not really designed to move large volumes of air, their hoses are relatively small, and the impellers on the motor are small too.
Why do I think this? Well, let's think about a typical floor nozzle in a vacuum, and what happens when a piece of dirt encounters it. Saying that the vacuum moves dirt is sort of a misnomer. What actually happens is that the vacuum removes the air in front a dirt particle, and the ambient air pressure beind the dirt then pushes it up the hose. If the air is removed faster, as in the case of a strong vacuum, the dirt particle moves faster up the hose, and a larger dirt particles can be picked up due to the lower pressure.
Now the issue comes when you want to pick up LOTS of dirt particles, which, if I'm not mistaken, is what the goal is when cleaning the house with a vacuum cleaner. In this case, one needs to not necessarily achieve a deeper vacuum to move the dirt faster, but it needs to swallow up lots of air that's ahead of all those dirt particles.
My own experience seems to be that high-volume vacuum cleaners seem to perform better than the high pressure ones. For instance, I have a little Hoover vacuum I use for cleaning electronics. It's got an extremely powerful motor, but a tiny fan and hose. It will pick up some pretty big stuff, but if one were to connect it up to a floor attachment, it's performance is dissapointing. The polar opposite of this is one of those big central vacuum installed in a machine shop. It's got a big fan in it that's comparatively slow turning. Although it would not swallow a bowling ball, It can swallow enormous amounts of sawdust and other shop dirt.
I would be interested in experimenting with various vacuum designs to see which actually picks up more or less volumes of dirt. The classic Electrolux model 30 (XXX) vacuum is famous for being a quiet, but effective vacuum. I imagine this is because it swallows up large volumes of air with a big blower. This would be in comparason to some of those little screamers avaliable nowadays. To perform an experiment, there will need to be many factors precisely controlled. The size and amount of dirt particles, and the density of their scattering will need to be closely monitored across the testing surface. I will then need to obtain a variety of vacuums of various shapes and sizes. The maximum negative pressure, and the CFM moved by each vacuum will need to be measured precisely. When the dirt pickup stage begins, each vacuum will need to have the same nozzle installed, and the nozzle will need to be pushed at the same time and distance for each vacuum. To measure the amount of dirt picked up, the bags will all need to be measured before and after the "dirt run" to see how much is actually in them.
It sounds like a worty endeavour, and it could dispel a lot of myths in the advertising of vaccuum cleaners that an extremely low pressure cleans better than a high volume of air moved....Then again, this is a lot of work for a simple answer, and my results are probably not going to be published anywhere significant...Maybe I could give this challenge to a high school physics class, or, the best thing is to ask vacuum cleaner experts, like the ones here....what do you think? Is it high volume of high negative pressure that cleans the best?
