FlowMeter

[chris_j_hunter]

probably not top of the list, but 'wonder if this idea could allow a simple / affordable approach to a flow metering :

http://www.eurekamagazine.co.uk/article/12466/Going-with-the-flow.aspx

with or without the pressure-sensing ...

and could Idratek be used to make it work - air-flow & water ? ?

[TimH]

Mmmmm. It's hard to know what they're judging it against when they make statements like:

“I think it will cost 50-70% of a conventional flowmeter,” he says.

What do they consider to be "conventional"?

and:

“In theory it should work – though we've not tested it yet,” he says.

Although they have done lab tests...

Presumably, for Idratek or any other system, the output will be a 4-20mA or 1-10V signal corresponding to the current flowrate relative to the max flow, so yes, it would be pretty easy to interface I would've thought.

Cheers,

Tim.

[chris_j_hunter]

aye ... difficult ... 'twas thinking, maybe, of doing something to measure flow-rates with both our ventilation system & our plumbing .. so, air & water ... our MHRV system will have fans, two each on inlet & outlet, the second on each used only for boost .. meaning, 'was thinking, maybe, when not on boost, the second ones could be used as flow-meters, using the technique described ... and that, with the plumbing, some sort of an arrangement could be devised to allow measured deliveries through taps ...

[Karam]

Interesting idea but imagine would be subject to some sort of IP. I think perhaps more aimed at areas which need high accuracies and better linearity across a range of flows. So might be easier and sufficient to stick with existing off the shelf solutions. Out of interest does your ventlation system have a variable speed fan - i.e. reason for measuring airflow and to what accuracy to measure?

Karam

[chris_j_hunter]

IP - yes, I imagine so .... over-accurate - maybe ... OTS solutions, yes, 'though they're not inexpensive, at least the ones I've seen ...

Our MHRV system (pipes being installed at the moment, two fans bought, heat exchanger unit soon to be ordered) will have four fans, two on each leg, so can run normally & can run furiously, for purging ... all fans variable speed, via the usual manually switched controller (to be interfaced in some way, to Idratek) ... the system's been designed for both ventilation & for dust-control ...

reason for wanting some measure - for HA feedback (absolute accuracy not important) & to know at what rate the system in ventilating (accuracy would be nice) !

Purging will be now & then, so rate-information not so important ... and the second pair of fans will be idle when not purging, hence the interest in the technique !!

The fans are AC ... more modern ones would (so I hear) be DC (more energy efficient, apparently) which might have been easier in this context !!

[TimH]

Chris,

A few more ideas here:

http://www.plantservices.com/articles/2006/165.html

No particular recommendation for this site, just one I found while googling

Often, repeatability is more important than absolute accuracy and while some methods aren't that accurate per se, they are reliable/repeatable.

HTH,

Tim.