I would like to measure air flow speeds in a duct system for dust collection in a workshop. Relevant air speeds in the ducts are around 10-30 m/s. The ducts are circular tubes with a diameter of 160 mm and thus the Re numbers will be around 100,000 to 300,000.
A pitot-static tube (a.k.a prandtl tube) in combination with an accurate-enough manometer appears to be the conventional measurement equipment for this application. My question is, do I really need a profesional-quality pitot-static tube for about 80-120 USD, or would it be sufficient with a 5 USD tube seemingly intended for RC planes?
In other words, what is the difference between a cheap and an expensive pitot tube? Can we expect substantial differences in performance (e.g., robustness, accuracy, ...), and if so what would be the relevant parameters? Or is it rather about which guarantees are made by the manufacturer? The factor 20 price difference suggests something fundamental could be different.
Does tip geometry play an important role? Is it important that static and dynamic pressure are measured in the same device? Is it important how the holes for dynamic and static pressure are located? Are the professional-quality obviously better in any such parameters?
Could I even do the measurement by measuring the differential pressure between (1) a hose with an opening perpendicular to the flow and (2) a thin, bent brass pipe with its opening oriented against the flow?
I am asking partly because I don't want to waste 100 USD, and partly because I want to understand the engineering considerations beyond the fundamentals of Bernoulli's equation.