Liquids flow just like gas, so they require unique flow measurement technologies to get accurate flow rate results. The type of liquid you want to monitor and measure depends on the fluid's properties and nature. Another factor that you should consider when selecting a flow meter is the application. This post will explore the various types of flow meters used in industries and how they work. Read on for more insights.

Different of Flow Meters

Essentially, there are five categories of flow meters used in different industrial and domestic processes and measurements. The list that we have complied below only mentions the most commonly used flow meters, but many of them are available in the market. 

Differential Pressure Flow Meters

When measuring the flow of fluid using differential flow meters, Bernoulli's equation is applied. A drop of pressure is experienced in the meter when there is a constriction within the pipe. The pressure drop increases when flow increases. To measure the fluid flow rate, impulse piping will connect the flow meter's downstream and upstream pressure to a transmitter.

In industries worldwide, 21% of flow meters belong to the differential pressure flow measurement technologies. 

They are widely used in gas and oil, power, pulp, chemical, wastewater, clean water, mining, pharmaceutical, metals, paper and beverage, and HVAC. 

PD (Positive Displacement) Flow Meters

PD flowmeters are also called mechanical flow meters. When measuring fluid flow volume, a flow meter will measure and deliver the fluid fast, and then it will refill again to repeat the process. To arrive at the flow rate, the amount of transferred fluid is calculated. The difference between positive displacement flow meters and other types of flow meters is that PD flow meters measure the actual flow of fluid while other types convert flow into liquids flow rate.

The output of these meters is correlated to the fluid that goes through the flow meter. A system is necessary in a PD type of fluids measurement to fill and empty the bucket. This system then divides the flow before the liquid exits the pipe. What contributes to the continuous forming and subsiding volumetric displacement are pistons found inside a cylinder on the flow meter walls. Rotary vane meters, rotating disk meters, oval gear meters, and piston meters are examples of PD flow meters. 

Velocity Flow Meters

To get the volumetric rate, the velocity of a stream is measured. A linear flow rate is pursued by the linear relationship in these types of flow meters. This means that compared to other flow meters, velocity has a better fluid measurement range. When Reynolds numbers (Re) go beyond 10,000, these meters' sensitivity goes down due to alterations of velocity. 

Conclusion 

Before opting to buy a flow meter, know and understand the type of application, you intend to use it with. The manufacturer will advise you which type of flow meter goes with which type you are unsure of. We hope that this article about flow measurement technologies was helpful.