What Is a Flow Cell?
A flow cell flowmeter is a type of orifice flowmeter that measures flow rate by generating differential pressure by installing an orifice in the piping. Water or air flows through the piping, and the value is measured and indicated by a float installed in the tributary flow.
Compared to other flow meters, orifice flow meters have a simple structure and are easy to install. However, they are not suitable for measuring substances with significantly different viscosity due to the pressure loss caused by the orifice in the piping and because they are mainly designed for water or air applications.
Uses of Flow Cells
Flow cell flow meters are used to measure and control the flow rate of piping in machinery.
They are mainly used in environments where high accuracy is not required, since they are compact, do not require calibration when measuring water or air, and can be maintained without stopping the flow by using a strainer.
For simple flow meters, the position of the float in the meter is directly observed when checking the flow rate. However, digital displays and devices that generate an alarm when the flow rate is outside the set range are also available.
Features of Flow Cells
Flow cell flow meters consist of an orifice plate and a flow meter installed inside a pipe.
When fluid contacts the orifice plate in the piping, differential pressure is generated, and the fluid flows into the flow meter section. This is a tributary flow, according to the magnitude of the differential pressure.
The fluid flowing into the flow meter section pushes up the float according to the differential pressure. The flow rate is measured by determining the amount of change and applying it to the Bernoulli equation. The fluid used for measurement is returned to the main flow through the return pipe.
Since the differential pressure generated in the pipe and the differential pressure observable in the flow meter are almost equal, and the flow rate into each pipe is proportional, the flow rate in the pipe can be derived by determining the flow rate in the flow meter.
Since flow cell flow meters are based on water or air at room temperature, correction is required for some types of fluids. Some products are also available with a hot wire sensor installed to compensate for changes in measured values due to temperature changes.