On the valve, does the arrow indicate the flow direction or the pressure rating?
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Some valve bodies have an arrow on them; this is generally interpreted as an indication of the flow direction, and the valve is installed accordingly. However, some sources state that this arrow indicates the direction in which pressure is applied to the valve, that is, the direction when the valve is closed. So, is it correct to install the valve according to the direction indicated by the arrow? @The wise are enlightened @Mighty Ultraman. @Nuts @Li** @RedLee_ZZHI @654262293
Flow direction indicator, which can be used to guide installation
So, is the direction of the fluid the same as the direction of the pressure? No
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What if the flow direction indicator and the pressure-bearing direction are opposite?
For directional valves, such as globe valves or eccentric butterfly valves, the flow direction and the pressure-bearing direction must be aligned to achieve self-sealing. Personal understanding
The pressure-bearing direction should be determined based on the on-site process; if it is the opposite after installation, then there is an issue with the setup
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The first valve is a butterfly valve, and this arrow indicates the flow direction. The second one is a gate valve, which does not require directional installation. The third one is a stop valve; this arrow indicates the installation direction. Usually, only check valves have a strict installation direction; globe valves are primarily related to opening.