The top 10 tips for installation of thermal mass flow meters/controllers:
1) Mounting position of flow meter
The mounting position is important. In general, it is preferable to install a flow meter in a horizontal position. Especially flow meters used for high pressures ( > 10 bar for by-pass instruments) should be mounted in this position. Avoid installation in close proximity to mechanic vibration and heat sources.
2) Avoid interruptions
Avoid abrupt angles – or any objects in the flow path which can cause turbulence - directly on inlet and outlet of your flow instrument, especially for high flow rates. We recommend at least 10x the pipe diameter as the distance between the angle and the inlet of the flow instrument.
If you are interested in why the choice of piping is important for thermal mass flow meters, please read our blog about the choice of piping for more tips
3) Name plate (serial number label)
Read the instrument’s name plate before installation and check the electrical connection, flow range, media to be measured, inlet and outlet pressure, operating temperature, ATEX classification (when applicable), as well as input and output signals. Also check the sealing material for compatibility with the process gas.
4) Electrostatic discharge (ESD)
The flow instrument contains electronic components which are sensitive to electrostatic discharges (ESD) – a sudden flow of electricity between two electrically charged objects caused by contact. Contact with electronically charged persons or objects could possibly endanger these components or even result in their failure.
5) Pressure
Do not apply pressure until electrical connections are made. When applying pressure to the system, take care to avoid pressure shocks and increase pressure gradually.
6) Check the piping
Ensure that the piping of the system is clean (before installing the instrument). For absolute cleanliness always install filters to ensure a moisture and oil-free gas stream. It is recommended to install an in-line filter upstream of the mass flow meter or controller, and if back flow can occur, a downstream filter or check valve is recommended too.
7) In line installing
Install the mass flow meter or controller in the line and tighten the fittings according to the instructions of the supplier of the fittings.
8) Piping diameter
Avoid small diameter piping on high flow rates, because the inlet jet flow will affect the accuracy and may cause too high pressure drops over the piping and adapters. Choosing the right piping diameter is also of importance to minimise the effect of turbulence as much as possible. Our previous blog describes the effect of turbulent flow and what to do about this.
9) Leak testing
Always check your system for leaks, before applying fluid pressure. Especially if toxic, explosive or other dangerous fluids are used.
10) Power up
Apply power to the flow meter or controller and allow for approx. 30 minutes to warm-up and stabilise. This may be done with or without fluid pressure, applied to the system.
I hope that this list is of use. Please feel free to use it as a reference for the next time you need to install a mass flow meter or controller. If you have further questions or if you think I have left anything out then please let me know. At Bronkhorst, we are happy to learn from your experience.
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