An instrument that is used to measure the flow rate of liquids and gases is a flow meter. When buying a flow meter, the familiarity of the working personnel with the device and their experience with calibration is what one should take into consideration. The maintenance factors such as availability of spare parts and the probability of failure are some factors one should put into consideration. One should also take into consideration the cost of installation of the flow meter. One should not buy a device because it is less expensive since this can be the most costly installations. One can consult an installation engineer when buying the flow meters just in case there are any flow measurement challenges. The basics to selecting the best flow meters are evaluating the nature of the process fluid and the fluid and flow characteristics. The piping and the area the flow meter is to be located one should also consider.
The characteristics of the fluid to be considered are the pressure, temperature, viscosity, density and many others. For the flow meter to operate properly these properties should have an indication of how they should interact. Also there should be a detailed composition of the fluid. Whether the fluid has solids and whether they are soft or abrasive or whether they have big or small particles this is to say that one should indicate. One should know the required meter range and this is done by identifying the minimum and maximum flows that will have to be measured so that one can select the best meter. Unless one knows the measurement accuracy, the flow meter’s performance may not be accepted over its full range. The flow meters without moving parts one should choose over the ones with them when purchasing flow meters. A cause of problems and failure are the flow meters with moving parts since they are prone to wear and tear. Clearance spaces for the moving parts that sometimes cause slippage into the flow being measured they also require.
There are different types of flow meters which include; rotameters, piston flow meters, paddlewheel, turbine flow meters, ultrasonic flow meters and magnetic flow meters. For in-line or insertion types the magnetic flow meters are available. They are ideal for any waste liquids that are conductive. Usually the displays are integral and an analog output can be used or remote monitoring. The ultrasonic flow meters are also used for dirty water or waste water. The frequency shift of an ultrasonic signal when it is reflected by discontinuities in the liquid flow is the principle of operation that is employed. The most used for liquids and gases on the other hand is the rotameter.Lessons Learned About Regulators