The flowmeter should generally be installed behind the valve, because the medium may appear two-phase after passing through the valve, the pipe is not full, and the flow phase is unstable.
These conditions will greatly affect the measurement accuracy of the flowmeter, so the flowmeter should be installed in front of the valve.
But because the pressure resistance of the flowmeter is limited, if it is a high-pressure occasion, the flowmeter cannot withstand this high pressure, then the flowmeter needs to be installed behind the valve, but you need to pay attention to several situations mentioned above, and try to avoid it.
The installation of the valve at the front and back is not absolute. For example, liquid turbines, gas turbines, and mechanical parts have movable parts.
If the flowmeter is behind, the pipe at the flowmeter may be emptied, and the next time the valve is opened, the flowmeter will have an impact. It is recommended to install it at the front end of the valve.
Some flowmeter installation positions do not worry about impact, you can install the valve on the front end. Ensure that the flow meter is full of pipes and that the flow rate flows through the flow meter at a stable and uniform speed.