Rotameter is one of the flow meter types we can find out in the market nowadays. The principle of rotameter to measure the flow is using the weight of the cone (commonly made of metal). In this article, I want to show you one of our experiences with using the rotameter. There are many design forms we can find on the market but the one we discuss here has the image like below.

There are some things we have to put in mind to install the rotameter correctly and let the rotameter works flow less. Those are as follows:

1. the rotameter shall be installed vertically because it is using cone’s weight as the sensing parameter to determine the flow rate and it needs gravity. If it is installed horizontally then the sensor (cone) will not work.
2. The flow direction, the inlet shall be at the bottom, and the outlet shall be at the top. Don’t miss about it during designing the piping.
3. The minimum input pipe length. The piping designer shall give the minimum length of straight pipe before the inlet, between the minimum length there must be no any elbow to keep the flow characteristic to be laminar because the turbulent or pulse flow will produce hunting measurement or the flow will continuously up and down quickly not in steady state.

We may have decided that the rotameter is the simple flow meter for our plant but we have to mind some guidance above and it will be important to be the instruction during the installation.