The arrow marked on the valve body is the recommended pressure-bearing direction of the valve, not the flow direction of the pipeline medium. The valve with two-way sealing function may not be marked with an indicating arrow, or with an arrow, because the valve arrow refers to the recommended pressure direction. It is better to have one direction in the left and right or up and down directions.
The direction of the arrow marked on the valve body indicates the pressure bearing direction of the valve, which is usually used by the engineering installation company as the medium flow direction to mark the wrong installation and cause leakage or even cause pipeline accidents;
The pressure bearing direction refers to the closed state of the valve after the valve is applied to the pipeline condition. The arrow direction of the valve body is the recommended pressure direction. If it is installed incorrectly, the valve may not close tightly.
Some valves are usually two way sealed, usually without arrows, which can achieve two way sealing, but there are better sealing performance in one direction. So there will also be arrows. You can consult the clients’ opinion firstly, on the recommended pressure direction.
Metal-seated butterfly valves with marked arrows are in different positions of the pipeline, and the direction of the arrow is different from the flow direction of the medium. For example, at the outlet end of the pump in the pump room, the arrow of the valve body is opposite to the flow direction of the medium, such as at the water inlet end of the water pump, the arrow is consistent with the flow direction of the medium. If installed on the main road, the arrow generally conforms to the flow direction of the medium, etc., depending on the working conditions and installation location.
