Hello Loki,
I will tell you up front that I am from Veris Inc., manufacturer of the Accelabar. However, I will strictly adhere to the posting policies and refrain from posting promotional information.
I would like to address the issue of turndown. JLSeagull is absolutely correct regarding turndown in that the supplier's description of turndown should be examined. Some DP primary elements express their accuracy as a % of RATE, meaning that you can expect the same accuracy from the PRIMARY element whether you are measuring 2" H2O of DP or 150" H2O. DP transmitters, however, usually express accuracy in % of full scale (DP produced slightly above maximum flow) with the accuracy gradually degrading as you move down the scale.
Nearly all flow measurement applications should be viewed as APPLICATION SPECIFIC in regards to turndown. For example, a DP flow meter may be capable of a 10-1 flow turndown, but if your pipeline velocity only produces a DP of 20" H2O full scale for a given meter, to achieve the stated accuracy over 10-1 FLOW turndown (100-1 turndown in DP), the flow meter/DP transmitter would have to measure .2" H2O as accurately as 20" H2O).
Whether it be a vortex meter, V-cone, Accelabar, or a Superduperflowmagic meter, ignore the turndown CLAIMS. If a meter claims a capability of measuring 15,000 GPM down to 500 GPM, is their 30-1 turndown valid if YOUR maximum flow rate is 2000 GPM? No.
Anyone can claim anything. The nuts and bolts come down to running flow calculations and determining the real world accuracy and turndown of your specific application. Independent flow test data, references and performance warranties wouldn't hurt.
Jake