cfms

rmarkham,

I am sure you will get many explanations on your answer. But to totally understand the proper answer you may need to first understand airflow and the physics involved. Most explanations I have heard have never really satisfied me in layman's terms. Maybe Ed Valentine could help here.

Most sales in our showroom are made by customers seeing if the open vacuum cuff will stick to their palm. Which incidentally is not good for the casing of your machine.

Ted has got it right about how it is. He has been in this industry for 31 years now and I have been here for 26 years, and we have both seen how it works. It is not a pretty sight at times.However, I am doing something to improve the wands out there. I started with the glides first, because the greatest restriction on the wand is at the WCI(wand/carpet interface). In other words, where the carpet meets the lips of the wand. This is where the greatest improvement can be made, and if adding a glide here can improve it as much as it does, that is a great start. But I have gone further than that. I am having a new type of wand built called the KH3 Titanium Wand. It is handbuilt to make it aerodynamic in the way air moves thru it, just like the way Ted is asking for. It will move up to 300 cfms with the big machines with the 5 series blowers , on the carpet! No other wand in the industry can do this. It sells for $1299 in Canada. In the future some of this technology will make it down to SS wands that sell for under $1000. But first they will have to steal it from me.

OK,back to CFMs. Laymans terms it is. High pressure always flows to low pressure, so to get the air to move into your wand(cfms), you need to create a lower pressure inside it(lift) than the pressure that exists outside the wand(atmospheric pressure). The low pressure(lift) is created by one of 2 ways, either an electric vacuum motor(s), or a large positive displacement blower. For purposes of this discussion, I will only consider the electric vacuum(s) as the source creating the lift here.

The atmospheric pressure will only enter the wandhead if there is enough lift(low pressure) generated because the carpet is pushed up to the lips of the wand while you clean creating a restriction to air movement. Full atmosheric pressure is just over 400" of waterlift(waterlift BTW, is the height that air pressure can raise a tube of water off the floor in a sealed glass tube if there was perfect vacuum at the top of the tube), but you do not need to create anything like this amount to do good cleaning. A singe 3 stage vacuum motor can create up to 140" WL(Water Lift), but this will only get about 30 cfms(cubic feet of air/minute) to move into the wand. Manufacturers know this, so build vacuum systems that puts 2 motors together in series(one vacuum feeding into another vacuum) to generate greater lift to move even more cfms(air) during cleaning. Two 3 stage motors in series will give you about 200" of waterlift or more, and cause 50 to 60 cfms of airflow(depending on carpet type) because the greater lift the wand has now, causes the air to rush into the wand much faster than before.Incidently, this also causes better cleaning and dryer carpets too. The air pressure inside both the hose and wand is now only half that of the atmospheric pressure outside it, so even the dense carpet at the wands lips does not slow the air down much. This is the reason you want to buy a machine that has high lift. Get the lift right and the cfms(airflow) take care of themselves. Only practical way(low cost) to improve them still more is put a glide on the wand(mine of course).

The reason that most cleaners do not understand this area very well is :

a) You can't explain it well in only a few sentences

b) most cleaners either never took or paid enough attention in science class

c) Not many good teachers around that can put things into laymans language so you don't need to be a rocket scientist to get it

Well this is as long an explanation as this 2 finger typer wants to give.

If you go to our site or better yet click here for CFR wands and tools. You will find products that in my estimation are aerodynamically designed for cleaners. The problem is they are very effective but overpriced for the average carpet cleaner when comparing it to an average PMF wand.

Actual tools and machines last for years and cost pennies per day. Look at labor and advertising. That's the high cost in our industry. Gas, trucks, rent, telephones, advertising, insurance etc. All of these makes your chemical and equipment long term cost almost insignificant.

Ken;

You have been in this Industry long enough to recognize who was one of the major pioneer and Professor of CFM's/Airflow because that is exactly where you acquired some of that knowledge. 

 Like Ted Harding , who developed and introduced to this industry, his handtool design---way ahead of anyone else---that would benefit the Professional Cleaner {a deserving credit that he never fully received in MHO, because there were others who pounded their chests in an effort to take away the credit instead), we are likewise, very proud of the fact that "We" accomplished , developed, and engineered the first High-Performance CFM/Air-flow concepts in a carpet cleaning machine that could go the distance. AND, that is exactly what I built this business on for 28 years now, and that is what we are known for.

Mr. Lee Stockwell, whom you know very well, is another longtime professional in this business. Below is part of a letter he wrote to us recently upon his visit proving what I mentioned above (for those who do not know me)

Posted By Lee Stockwell on 10/1/2004 at 6:49 PM

It was great to finally shake your hand after knowing you for so long. In 1978 I talked to Ed and his longtime employee Jim, just before we bought our first Bane unit. Ed was gracious and helpful anyway. As it turned out his advice was right on the mark then...just as it is now.

I admire the Valentines about as much as anyone in the industry, and if you ever visit him in Ann Arbor you will know why.

He patented the first practical vacuum booster decades ago. The early ones were all metal with 2" ports. His new ones are the best yet. I'm surprised more cleaners don't know about them.

He has also championed CFM long before it was "cool" to do so. Give Ed credit when you see the "me too" machines coming out lately. The new electronics needed to tweak maximum performance out of electric motors was very interesting. I reminded him as he was showing me the components that I had and electrical engineering background, and that I recognized them even without the insignia. I won't tip his hand though.

______________________________________________________

In conclusion my  friend, do not attempt to convey to others, or pull up the covers on my personal knowledge and history of CFM and the development of Air-Flow.

Wishing you and your company the best;

Good Fortune to;

Ed Valentine

Cross-American Corp.