>>You can also check out http://www.captor.com/ -- click on the "flow captor" >>link. > Do they use pressure change to calculate the flow rate? No. They use the calorimetric method -- reading a (self)heated temperature sensor, in various variations. Gerhard -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu