Standard orifice plate, installation, straight pipe section
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May I ask what the required lengths of straight pipe sections before and after the installation of a standard orifice plate are? I’ve seen some specifications stating 10D upstream and 5D downstream； But the algorithm specified in GB/T2624-2006 is quite complex, and the requirements are rather strict. Thank you! Also, for the rotameter, is it 5D at the front and 250mm at the back?
Strict requirements are needed to obtain accurate data. The length is calculated based on the pressure tapping method and pipe diameter. If it seems complicated, you can ask the orifice plate supplier to prepare the straight sections before and after it, so that it can be installed directly.
The manufacturer can be responsible for the calculations; generally, the longer the straight pipe section, the better. For rotor flowmeters, it’s 5D at the front and 250 mm at the back
What are the requirements for the first 10D and the next 5D? It is necessary to check what flow-blocking elements are present in front as well as the β value. The ISO5167 standard specifies corresponding requirements; for example, when there is a fully open gate valve in front, the β value is 0.4, and the straight pipe section is required to be 12D in length ahead and 6D behind