300+ cfm

[Walt]

If 300 cfm is the max amount of you can get through one glided wand, why do single wand machines come with more than that? Wouldn't it be better to additional power in lift, not additional cfm?

Wouldn't a 300 cfm blower with say 18+ inches of lift be a better combinations then a 500 cfm blower with 14 inches of lift?

 

[Out of Character - 0]

If your using a traditional spring relief valve then you need more air to compensate for the waste. + as you lift goes up, so does the amount of air sucked in through the relief valve provided it's not a precision valve. Add leaky 2.5 cuffs and you'll need a bid more.

But then you have the 500 cfm machines that only put out 350.

 

[Greenie]

It's my opinion that a little "air to spare" doesn't hurt.

That said, your example of 300 cfm is already allowing for that, as i've yet to see 250 cfm proven to pass through a glided 14" wide 2" dia. wand.

I think to have a snowballs chance in hell of getting 300 throough it, you would need 2.5" hose hooked to that wand....that at least would give you your "full operating Lift" at the wand, since the 2.5 preserves lift becuase it's a more efficient conduit.

Now back to your orig. question, I think it's more of an engineering question, it's a lot harder on belts and such to support 18"hg than it is 14", takes more horsepower etc...

This is where BIG hose comes in...a real 14" hg AT the wand is sweet...don't "need" 18".

 

[truckmount girl]

Theoretically if you can only pass 300 cfm through the wand/glide, then your lift will raise until the relief valve opens. A higher lift blower will stress your other components (waste tank, coupler, vac hose, etc.), so just leave your relief set between 14-18 depending on your setup and quit worrying about it.

Take care,
Lisa

 

[Duane Oxley]

It's all about straining the system for more heat. Placing the system under a constant strain gives more consistent heat, because it smooths out the "valleys" between when the wand gets a better grip on the carpet. During those "valleys", the temperature also dips down a bit. So, loading the system helps with that. And a larger blower than necessary is one common way top do it.

You don't see a 47 or larger blower on a system that has a secondary- fuel burner, unless it's a dual- wand system.

 

[truckmount girl]

Component life vs. heat....there are plenty of other ways to get consistent heat. I'd rather protect my major investment.

Take care,
Lisa

 

[Hoody]

I will say that I may be totally wrong on this. So if I am please someone correct me.

It is my understanding that there has to be proper balance between lift, and CFM.

Lift is the initial suck at the wand to carpet interface.

CFM is how fast the water is being recovered.

At shorter hose pulls the higher CFM is almost "wasted" as in theory a lesser CFM could recover the water just fine. As the hose lengths get longer, the CFM's drop, but the amount of availiable lift actually increases. The issue with the longer hose pulls is when then machine reaches its choke point and the relief valve opens(as well as the wand stroke being finished); the hose is filled with more water than what it can properly recover with the lesser CFM's. That then puts more restriction, lessening the amount of available lift until the hose finally clears out.

So with that said. It makes sense that the higher CFMs with a lower lift would be more beneficial, in the long run(yes pun intended) The only reason to increase the lift to 18" is if you were wanting to get more heat out of the blower exhaust.

Right or wrong?

 

[Greenie]

Hoody,

I won't say you are wrong, just off target a bit.

The detriment to looooooong hose runs is friction, this is seen easily in the robbing of avail. lift. There is surprisingly very little drop in CFM, it's the lift that takes the hit from friction.

It's also the reason a centrifugal vacuum (portables) suffers on long hose runs, where a positive displacement blower doesn't nearly as much. Centrifugals only pull so hard, then they self rescue (kind of "slip the clutch") to prevent from overheating. So you have Less lift to work with, hence the greater the need for "large" hose on elec. machines whereas PD blowers can pull more through a smaller hose all things being equal.

That said, if you can actually get 10-12"HG of real Lift to the wand, you would never want for or need more, it's all about preserving the lift enroute, hence big hose a much better at preserving the lift, same holds true for liquid in a hose, 3/8" hose loses 1/4 the pressure of 1/4" hose...but it's not as big of a deal...cause we can "usually" turn the Pressure UP to compensate, not so for vacuum.

 

[Chris A]

So back to the original question, why are TM manufacturers making 47 class Heat Exchanger single Wand machines? How much CFM and lift are lost through blower exchangers?

 

[Duane Oxley]

So back to the original question, why are TM manufacturers making 47 class Heat Exchanger single Wand machines? How much CFM and lift are lost through blower exchangers?

Because the blowers are used as a heat source for heat exchange systems. And the bigger the blower (and the motor) the more heat is available.

Ultimately, it has little or noting to do with airflow.

 

[GeneMiller]

I think the real reason is because we are convinced that we need it, the whole male ego, mine is bigger then yours. The manufactures know their target audience and use bigger and bigger blowers because we will want it and they can charge more for it. I looked at the new 370 sapphire today, it looked so small, it reality it's probably all I need.

Gene

 

[Greenie]

I agree with Duane, again.

and the simple fact that cleaners think they "need" a 500 cfm blower.

I have a good customer who insist on running a single 2" hose, he makes 200' hose runs routinely (apts), he absolutely insist he needs a 47 class blower. I just say ok..... you should hear the relief valve.

 

[Hoody]

So then explain why the machine bogs down until the hose clears ?

 

[Larry Cobb]

Walt;

Congratulations.

You are correct in your analysis.

225 CFM is the maximum that I have measured from a 14" glided wand, with 16" hg. at the TM.

Lift is the factor to maximize at the wand to generate the most CFM thru the carpet.

Larger hose lose less lift going to the wand.

Higher lift at the TM, maintains more lift at the wand.

Higher CFM is a marketing ploy put forward by PC and others.

That is why we now use the #4MR Sutorbilts @ 17" hg.

Larry

 

[Greenie]

So then explain why the machine bogs down until the hose clears ?

I'm not sure of the exact nature of your question, but in general if your machine "bogs" under heavy load, it's a torque/horsepower thing....all units will bog some, just depends on the load.
If your machine bogs under flood water extraction I wouldn't be so worried, especially if pulling SOLID water through the hose for short periods, if it bogs with carpet cleaning, I would look into it, it's possible the rpms aren't set above the torque curve, or the powerplant is underpowered for the task at hand, also check your vacuum releif, could be set too high for a heavy load with your current horsepower to blower ratio.

 

[Hoody]

Thanks Greenie.

By bogging down I mean I can hear a distinct difference in the air through the hose. After cleaning for a while on long hose runs(350+ ft) it sounds like I'm not getting much air flow. I go and move my hoses and the wand has the great suction it had before.

 

[Able 1]

Thanks Greenie.

By bogging down I mean I can hear a distinct difference in the air through the hose. After cleaning for a while on long hose runs(350+ ft) it sounds like I'm not getting much air flow. I go and move my hoses and the wand has the great suction it had before.

Anti-foam... well at least in my case. Powerburst really dosen't foam that much but on a run of 450' I noticed the same thing your talking about. Too much aggitation on the way to the waste tank causing suds?? I also think with the longer runs this might be the first time they got a good flushing from a TM, lots of soap left in the carpet from porty hacks. :shock:

 

[Hoody]

Doesn't matter the age of the carpet nor the juice. I even tried a sample of procyon on 3 month old carpet, same thing.

 

[Walt]

I've had the same experience on very long runs. Seems to be exacerbated by high flow and some foamy cleaners.

The engine never slowed.

 

[Able 1]

Doesn't matter the age of the carpet nor the juice. I even tried a sample of procyon on 3 month old carpet, same thing.

Did you try anti-foam? I would notice a drop off then would throw some of that stuff on the carpet and I was back in biz.. Not just in the tank the foam is in the vac lines..

 

[Hoody]

Yes, a defoamer or a lightly mixed acid rinse works well. If I know there is going to be a residue issue I'll mix a gallon of it and take it in the building with me.


Back to the original point. I was just making sure/asking is/can the reason be in the delay of getting the vac back to full strength is a loss of CFM when on longer hose runs ?

 

[Able 1]

Are you using 2.5? On the 450' run 200' was 2.5... I would never try to run that distance with 2"... vortex maybe?

 

[Greenie]

It's not a hose issue alone, a PD blower does not like to suck foam, they cavitate, they need to have clean air to pull against....so yes you have a cfm loss. Long lived crystal defoamer! lol

And Yes, 2.5 is much much better for this.