Why do straight piping requirements for flow meters even matter? The answer to this question is surprisingly simple. For many flow technologies, turbulent and swirling media within a pipe is hard to measure in a reliable and accurate manner. There are many obstructions and details within a piping system that case cause a flow profile to become turbulent. If this occurs relatively close to flow meters, it can lead to significant errors as high as 50% of the reading.
There are many types of variables and configurations that can lead to an undesirable flow profile. Some common examples are bends in the pipes from elbow joints, control valves, pressure taps, T-joints, other instrumentation, thermowells, reducers, and more. Anything that can cause the flow to move in a non-linear way needs to be properly accommodated for to ensure the accuracy of your flow meter readings.
Different flow meter technologies have different straight run requirements, based on the inherent principle of operation being used. The requirements are usually expressed in terms of the distance away from the flow meter in a multiplication factor of the pipe diameter. They are also expressed as being either upstream (from the instrument) or downstream (from the instrument). It is important to consider straight run requirements ahead of time to ensure that the flow meter you select will fit in the space that the current system already has to offer.
While there are some general ballpark rules of thumb that can be used in reference to the straight run requirement for the flow meter technology type, each application may have its own special unique considerations that will need to be accounted for when choosing a flow meter.
Always consult the manual that came with your flow meter for exact straight run requirements as the following information below is only a general reference. If you are unsure, you can always contact our expert engineers for fast and free flow meter selection help.
Still confused about which flow meter technology may be best for your application? Learn more about choosing a flow meter in our in-depth article or call one of our knowledgeable engineers now for fast and free assistance.
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