What are Industrial Flow Switches?
Also known as a flow sensor or a flow indicator, a flow switch is a measuring device used to monitor liquid and gas substances' pressure and flow rate through a system, loop, or duct. Monitoring flow rate can be done over a set period to monitor the total flow rate continuously. Not all flow meters are flow switches because some of them only display or register flow rates.
Most flow switches can start or stop other components or trigger an action. A pump is an example of a component that can be started or stopped with a flow switch. By doing so, the operator can adjust pressure or flow rate to the desired set levels. If a flow rate device can do this, then it's a true flow switch.
How Do Flow Switches Work?
You first have to know the various components of a flow switch to understand how it works. The primary device is made up of a magnetic trigger or paddle. The primary device is placed in the channel where the liquid or gas passes, connected to a circuit. The fluid that goes through the pipe rotates or displaces the paddle. Signals are then sent to the transducer, which is the secondary component. Raw signals from the paddle are taken in by the transducer and pass it to the transmitter reasonably. The transmitter then uses preset parameters to measure the readings. Once the signal is gotten from the transmitter will trigger an action needed to adjust the component(a).
This process allows flow switches to monitor, report and control the fluid's flow rate. It also ensures that the flow rate is maintained in one part of the system or the entire system based on the preset parameters. A flow switch can trigger a series of actions immediately after the pressure or flow rate goes above or below the expected levels. The series of actions may be powering the pump, shutting down one or a few areas of the system, diverting an alarm, or diverting the flow. The flow switch design and its type will determine which action will be taken.
Flow switches may or may not have paddles. An example of a flow switch that doesn't have a paddle is the ultrasonic flow meter. This flow switch monitors the flow rate by bouncing a signal back off the medium. This and other non-intrusive flow switches usually measure the flow rate of fluids and gases that are contaminated or hazardous. They are also useful where there are no moving parts that may succumb to wear and tear.
Other examples of simple flow switches that restrict, measure, or allow fluids to flow are rota flow or variable area flow sensors. These flowmeters have tapered tubes with floats or electromagnets, which allow, restrict, or measure flow rate and pressure. Electromagnetic flow switches only measure the flow rate of conductive liquids or gases.
Types of Flow Switches
Flow switches come in various types, which use different approaches of measuring or monitoring linear, volumetric, non-linear, or mass flow rate of fluids. Before purchasing a flow switch, you need to ensure that it fits the kind of application you've got set up. Flow switches are designed differently based on the application they are supposed to work with. Failure to get a proper flow switch may lead to inaccuracies when monitoring or measuring flow rate.
Water and Fluid Switches
Physical paddles or ultrasonic wires directly into the flow channel are used in water flow switches. The transducer indicates the flow rate. The transducer takes the information to the transmitter, which turns it into an action or signal.
Magnetic Water Flow Switches
Magnetic flow switches use the principle of Faraday's Law of Electromagnetic Induction. This law states that the voltage induced is proportional to movement speed when a conductor (fluid) passes through a magnetic field. Water passing through a pipe generates a magnetic field depending on how fast it moves inside the pipe. This will, in turn, give out the flow rate reading. The accuracy rate of a magnetic flow meter relies on how conductive the medium is. These types of flow switches are used in wastewater systems.
Inline Water Flow Switches
Installed as an integral part of the overall system, an inline water flow switch is installed permanently. Installing and maintaining online flow switches involves a complicated process. It is also more costly than other flow switches. However, they work properly even with shorter straight run sections.
As you can see, water flow switches are vital tools for monitoring and measuring flow rates in liquids and gases. The accuracy levels vary depending on the type of flow switch and the application it is designed for. When searching for a flow switch, ensure that it matches with the application it is meant for. If you are not familiar with the application and flow switches, ask the manufacturer for directions.
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