This is Ken's full post. I don't think he has an axe to grind. I've only met him a couple of times but he always comes across as a decent bloke.
"We got back from Piskey Land last night and I must say that the Cornish hospitality was as good as ever. Big Thanks to all the team at Solutions.
Despite my growing years, I did actually remember to ask Nick and Colin to measure the vac performance of my Jag both on arrival and prior to departure.
Machine in, airflow in was 271.1CFM's and as near as 10" Hg as you can get. At every stage, Hg remained consistent, so I wont mention it again.
After conversion, the Jaguar was tested in many ways. First off, it measured 358cfm's. That's a "free" improvement of 32%. Can't be bad that. Same vacs, no extra power consumption and, hopefully, even better cooling.
But 358cfm's isn't the whole story. We discussed between us the variation in figures that Nick records from the same machines at different times. This can be quite significant. The theories we threw into the pot was varying climatic conditions ie higher and lower air pressure affecting the readings. But the most significant variations I have noticed throughout my career is the electricity supply. Even with my Sebo vacuum, I can tell by the sound of the brush motor whether the voltage is high or low. It is certainly noticeable too at the end of the Westpac. The day after the Jag conversion was completed, Nick again took cfm readings whilst I was there, and they varied somewhat in the low 360's. For my own machine, I am therefore going to say that I have 360cfm's
Now for a big twist. I want to "turn" the vac exhaust so that it blows away from the machine, keeping hot air away. Nick made up a shaped baffle/diverter plate for this purpose. CFM's actually increased:shock: By delicate manipulation of the baffle the figures went into the high 360's. But then Nick tried it with just his hands acting as the baffle/diverter and we found that in specific position with his hands cupped into a specific shape, we had consistent readings of 374cfm's. :censored: hell! Fluid dynamics is certainly a complex issue!
Now another dynamic. There has been low level research in the US, using a high end T/M as the source, to find the optimum cfm's through a 50ft hose. Tests were carried out, so I'm told, with extended runs, 4 to the door, a straight 50ft plus other configurations and the results were similar for every configuration. 260cfms. The conclusion of this test, so I'm told, was that 260cm's is the max. achievable under normal circumstances, but a powerful T/M will achieve the same fugure over longer hose runs than a lower spec machine. To be honest, I'm a little sceptical about this research but I won't discredit the results either. More needs to be done.
So, we measured the modified Jaguar with 50ft of new hose attached. 270cfms' and the same 10"Hg.
I'm happy:woohoo:
Probably wont be rinse extracting until later in the week, but I'm all excited at the prospect. "
He then corrects this by saying the figure 274 was a mistype and should have read 274.