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BillA · 04-01-2005, 10:17 AM

one has to have a plan, patience, and perseverance
(sounds too much like life)
mag flow meters can be had cheaply on eBay and LabX
learn the mfgrs, and which flowtubes can be used with different mfgrs xmitters
I prefer Danfoss (one more digit resolution), but Rosemount, Foxboro, Yokogama, Brooks, Sparling all work for me

I used to believe that a 1/4" flowtube was necessary for low flow rate accuracy, but I recently put a 1/4" and a 1/2" in series and compared the flow indicated and dp
- I was surprised to find that the difference between the 2 was a nominal 0.005% (the Rosemount 1/2" being 'high')
-> based on this I would suggest that 1/2" flowtubes be used for our type and range of testing

note (again) that the flow meter does not need to be in the system, anything (wb, rad) can be 'calibrated' by generating a dp/flow curve, and the flow then known by reading the differential pressure across that item
- note that the ASME size of the pressure tap holes is D/10

http://cgi.ebay.com/ws/eBayISAPI.dll...MEWN%3AIT&rd=1

04-01-2005, 10:17 AM	#16
BillA CoolingWorks Tech Guy Formerly "Unregistered" Join Date: Dec 2000 Location: Posts: 2,371.493,106 Posts: 4,440	one has to have a plan, patience, and perseverance (sounds too much like life) mag flow meters can be had cheaply on eBay and LabX learn the mfgrs, and which flowtubes can be used with different mfgrs xmitters I prefer Danfoss (one more digit resolution), but Rosemount, Foxboro, Yokogama, Brooks, Sparling all work for me I used to believe that a 1/4" flowtube was necessary for low flow rate accuracy, but I recently put a 1/4" and a 1/2" in series and compared the flow indicated and dp - I was surprised to find that the difference between the 2 was a nominal 0.005% (the Rosemount 1/2" being 'high') -> based on this I would suggest that 1/2" flowtubes be used for our type and range of testing note (again) that the flow meter does not need to be in the system, anything (wb, rad) can be 'calibrated' by generating a dp/flow curve, and the flow then known by reading the differential pressure across that item - note that the ASME size of the pressure tap holes is D/10 http://cgi.ebay.com/ws/eBayISAPI.dll...MEWN%3AIT&rd=1 Last edited by BillA; 04-01-2005 at 10:40 AM.