Based on our experience, the following tips can help customers to distinguish butterfly valves from uni-directional or bi-directional structures.
1. For some factories, they put two flow arrows on the valve body, because they trust the installation of valves on either direction is workable ,but this will reduce bi-directional butterfly valve’s service life, especially when it has a floating seat. The bi-directional butterfly valves made by JONLOO only has one arrow indicating the main flow direction, because we believe that there must be main-stream and minor-stream in any pipelines. To extend the service life of valve, customers must have the valve installed with arrow indicating the main flow.
2. Pay attention to the structure of seat ring. There are usually two different kinds of structure for the seat ring. One is floating seat ring and the other is ordinary type. The floating seat ring can be easily found out by the professionals. While, for ordinary seat ring, which has the same design as uni-directional butterfly valves, is not easily found out. But it needs larger stem and worm gear.
3. Getting information from the nameplate. For bi-directional butterfly valves, the model usually starts with Ds, and for uni-directional valve, it starts with D. While, for different factories, they may have their own difinition on model.
