Why is airflow always measured?

[cheesewonton]

Incidentally, It's not clear what that "150 Watts of suction power"

It refers to the Suction Work Rate according to the Japanese standard.

 

[cheesewonton]

This is nice to see, but it's not relative cleaning performance data.

That is the most uninformed statement imaginable. Without suction and airflow you don't have cleaning power. Pretty basic stuff.

 

[cheesewonton]

Watts can technically be measured anywhere in the system"

But again the Japanese standard measures Suction Work Rate at the attachment end. The Japanese standard is very detailed and specific that way and why comparisons of vacuums rated by the Japanese standard are objective.

 

[Vacuum Facts]

It refers to the Suction Work Rate according to the Japanese standard.

I'm not convinced from their advertising, but it is believable. Also doesn't translate into cleaning performance on carpets.

This is nice to see, but it's not relative cleaning performance data.

That is the most uninformed statement imaginable. Without suction and airflow you don't have cleaning power. Pretty basic stuff.

What you said is true, but cleaning performance needs to be measured directly since, as discussed in the previous response, there are other factors associated with the cleaner head. Direct measurements are needed, not values from indirect variables. The science of this is well known and discussed in the lecture you write off as complicated. Well the real world is and if you want to understand it, an investment in education is needed. I've kindly made it available for those who want to learn, and it's accessible to the age of about 16.

Watts can technically be measured anywhere in the system"

But again the Japanese standard measures Suction Work Rate at the attachment end. The Japanese standard is very detailed and specific that way and why comparisons of vacuums rated by the Japanese standard are objective.

Again true. No argument from me. However, their standard measures for effectively one particular use case that isn't universally applicable to all situations (unlike the ISO). And it's only relevant for above floor cleaning. You claim it's for a tool sealed to a surface (which makes sense), but this is different to tool extracting from a deep crevice. Air watts are fixated on too much and not many seem to understand their value. Their real value for floor cleaning is outlined in the lecture associated with various low resistance flooring that allow high air currents, and more air watts sustains suction and air speed. All well understood and has been for a few hundred years.

 

[Absolute Rainbow]

@cheesewonton @Vacuum Facts please tell us all the differences between the Japanese Suction Work Rate and simple airwatts, so people would know, notice and be able to distinguish the two.

Also, here's a video for dummies, made by none other than @Vacuum Facts:

 

[cheesewonton]

@cheesewonton @Vacuum Facts please tell us all the differences between the Japanese Suction Work Rate and simple airwatts, so people would know, notice and be able to distinguish the two.

Also, here's a video for dummies, made by none other than @Vacuum Facts:

The primary difference is that the ISO Air Watt measurement is an instantaneous measurement of both airflow and suction at a given diameter orifice. It is a snapshot in time. Vacuum motor manufacturers will take this measurement at different orifice sizes starting at a closed orifice. At that point you get maximum suction and no airflow. Since Air Watts are Suction in Pascals multiplied by airflow in Cubic Meters per Second the Air Watts at a closed orifice is zero. The manufacturer will take airflow and suction measurements at progressively larger orifices and calculate the air watt value for that orifice until they reach a maximum orifice size, typically 50-52m at which point suction is nearly zero and airflow is maximum. They will also plot Airflow and Suction vs Orifice size. Where those graphs intersect, typically around 20-25 mm orifice size maximum air watts is achieved.

By comparison the Japanese standard measures maximum sealed suction at the hose end or the orifice in the nozzle of an upright, and they also measure the quantity of air that flows through the hose or suction nozzle over a period of time. This compensates for the difference in the speed of air flowing through a hose or tube from the center where it is highest to the walls where it is nearly zero. Instead of measuring air speed at the center and applying a rule of thumb correction factor the Japanese simply measure the total volume of air that flowed over a period of time. The measured suction and air volume are multiplied together and this value is multiplied by a factor to arrive at their Suction Work Rate.

 

[Absolute Rainbow]

The primary difference is that the ISO Air Watt measurement is an instantaneous measurement of both airflow and suction at a given diameter orifice. It is a snapshot in time. Vacuum motor manufacturers will take this measurement at different orifice sizes starting at a closed orifice. At that point you get maximum suction and no airflow. Since Air Watts are Suction in Pascals multiplied by airflow in Cubic Meters per Second the Air Watts at a closed orifice is zero. The manufacturer will take airflow and suction measurements at progressively larger orifices and calculate the air watt value for that orifice until they reach a maximum orifice size, typically 50-52m at which point suction is nearly zero and airflow is maximum. They will also plot Airflow and Suction vs Orifice size. Where those graphs intersect, typically around 20-25 mm orifice size maximum air watts is achieved.

By comparison the Japanese standard measures maximum sealed suction at the hose end or the orifice in the nozzle of an upright, and they also measure the quantity of air that flows through the hose or suction nozzle over a period of time. This compensates for the difference in the speed of air flowing through a hose or tube from the center where it is highest to the walls where it is nearly zero. Instead of measuring air speed at the center and applying a rule of thumb correction factor the Japanese simply measure the total volume of air that flowed over a period of time. The measured suction and air volume are multiplied together and this value is multiplied by a factor to arrive at their Suction Work Rate.

Since @Vacuum Facts thinks airwatts are better... How about people measure airwatts for above-floor-plus-crevice performance (like he suggested in his videos), and use the Japanese standard for base floor cleaning, at least in Japanese market? Also, it's not like you necessarily needs so many airwatts, because all of it would be wasted away by a sufficiently sloppy cleaner head, just like Vacuum Facts himself noted.

 

[Absolute Rainbow]

Measuring the airflow:

 

[cheesewonton]

Since @Vacuum Facts thinks airwatts are better... How about people measure airwatts for above-floor-plus-crevice performance (like he suggested in his videos), and use the Japanese standard for base floor cleaning, at least in Japanese market? Also, it's not like you necessarily needs so many airwatts, because all of it would be wasted away by a sufficiently sloppy cleaner head, just like Vacuum Facts himself noted.

The air watts of the motor can be in some cases irrelevant to what is happening at the hose end. Example. I am weird for Tristars and their several imitations from Miracle Mate, Schoettler ( Airstorm and Patriot among others ) and Vortech. I have Tristars going back to the very first Compact Model 1 circa 1944-45 up to the most recent models. All of them have hoses with a 28 mm inside diameter at the spout. And every single one of them regardless of the year made or the motor installed produce 27 to 28 cfm at the hose end. The OEM motor in a Tristar DXL is rated at 356 peak air watts. I have an EX-30, which is basically a DXL with a different upper body shape for the Japanese market I converted to a 120 volt machine. I have used different Ametek motors in it with peak air watt ratings of 356, 447 and 489 air watts ( 116884-49 the original DXL motor, 115923 and 119347-01 respectively ) as well as an Electromotor Inc. 6500-298 two stage motor rated at 438 air watts. All of these produced the same 27-28 cfm. I also have a couple of the current Tristar bodies used with the EXL, MG and CS series into which I have finagled other motors. They came with a VM3 motor that I have no data for but even this newer Tristar only produces 27-28 cfm. Wimpy by modern standards. I put an Electromotor 6500-298 in one and it still makes only 27-28 cfm. I put a 600 air watt Panasonic 3D Inducer Motor in one that came from a Kenmore Elite. That gave me a rip roaring 29 cfm at the hose end. The exact same motor in a Kenmore Elite with its 40 mm hose end gives me 43 cfm.

I put that Electromotor 6500-298 in an old Electrolux Epic 8000. These have a hose with a female hose end that is 38 mm diameter. The same motor that only produced 27-28 cfm airflow in the Tristar produces a healthy 61 cfm in the Epic. The Epic has a larger diameter hose and a really huge exhaust opening so there is very little airflow restriction, where the Tristar has a smaller 28 mm hose opening and because the exhaust is also designed to accept the hose and be used as a blower the exhaust opening is very small too.

I have a Sanitaire SP6952 in which I literally doubled the airflow at the hose end by doing detailed clean up of the hose ends. There were sharp edged corners, molding flash both of which are terrible for airflow and the inside surfaces of the hose ends were shiny and smooth which creates a boundary layer of dead air along the walls, effectively reducing the inside diameter of the opening. I sanded down the molding flash, rounded the sharp edges and sanded the inside in the direction of airflow to break up the boundary layer, all stuff I learned to increase airflow in cylinder heads and intake manifolds on gasoline engines. Doubled the airflow, no other changes.

 

[Vacuum Facts]

Since @Vacuum Facts thinks airwatts are better...

This is inaccurate. I've repeatedly said airwatts are misunderstood and fixating on them has limited value.

 

[cheesewonton]

The thing I like about the Japanese rating system is that it is based on suction and airflow at the hose end or nozzle end depending on the configuration of the vacuum and the standard is applied consistently across all vacuums.

 

[Vacuum Facts]

Yes, as above, It's fine, but it represents a specific use case and doesn't inform the potential for other use cases. Knowing the air power only has limited value. Most people don't appear to understand. It's all in my lecture video. Marketing love it because they can one up with it. It's of little value to the ordinary user. It's also not as valuable as industry standard determined cleaning performance.

 

[Absolute Rainbow]

ISO Air Watt measurement is an instantaneous measurement of both airflow and suction at a given diameter orifice. It is a snapshot in time. Vacuum motor manufacturers will take this measurement at different orifice sizes starting at a closed orifice. At that point you get maximum suction and no airflow. Since Air Watts are Suction in Pascals multiplied by airflow in Cubic Meters per Second the Air Watts at a closed orifice is zero. The manufacturer will take airflow and suction measurements at progressively larger orifices and calculate the air watt value for that orifice until they reach a maximum orifice size, typically 50-52m at which point suction is nearly zero and airflow is maximum. They will also plot Airflow and Suction vs Orifice size. Where those graphs intersect, typically around 20-25 mm orifice size maximum air watts is achieved.

Measuring the airflow:

Since @Vacuum Facts dislikes the cubic-feet per minute, and there's the excessive overestimation if done wrong, I'm going to technically add to the formula, based on existing stuffs. This will apply to the ISO airwatts only, which has currently been used internationally.

ASTM F558-13 have us the common formula, which is the simplest one out of some other formulas out there, and graciously gave us the exact formula: 0.117354×F×S, F is for CFM airflow, S is suction level. An easy yet surprisingly accurate approximation would be 2/17×F×S. However, there's two direct problems with the formula in question:
- @Vacuum Facts thinks that CFM, the imperial, is outdated (measuring airflow video, timestamp is 6:20), so I am going for liter per second. 1 l/s = 2.11888 CFM, 1 CFM = 0.47194745 l/s.
- It's mistaken the water lift (in.H2O) with suction. You should be using the kilopascal (kPa) instead, and 1kPa = 4.01865 in.H2O and 1 in.H2O = 0.249089 kPa.
So the actual formula (in bold) should be: [AW] = 0.117354×[CFM]×[kPa] = 0.117354×2.11888[l/s]×[kPa] = 0.248659×[l/s]×[kPa] = 0.248659×[l/s]×0.249089[kPa] = 0.0619×[l/s]×[in.H2O] = 0.117354×[CFM]×0.249089[kPa] = 0.0292×[CFM]×[in.H2O]

You can only get away with rational approximation with the CFM-kPa version of the formula because it's incredibly accurate, especially for such simple fraction. It's best that you guys all use the more accurate full numbers like I did.