How a Flow Switch Works

Although a flow switch is a very simple little device they are essential in a variety of different applications. They can be used to protect a pump, monitor the flow of a liquid, gas or air through a specific line as well as trigger alarms when necessary. The switches are also used to turn cooling circuits on to provide protection to engines, motors and many other types of devices.

In its most basic form the flow switch is used to sense the flow or passage of a fluid or air through the valve contained with the switch. This valve is set to send an enhanced or decreased electrical signal which then is read by a switching unit that can either turn a pump or valve on or it may also be used to turn it off. Options that are attached to alarms work using the same theory. If the flow volume through a given system decreases below a specific pressure or increases above a pressure the electrical signal triggers an alarm.

Flow switches can be used in a variety of different applications. They are very commonly used in reservoirs and tank storage systems to keep each tank full. They are also frequently used in pipelines to ensure that the flow of whatever liquid is being transferred down the pipeline is continuous. These handy types of switches can be instrumental in discovering and identifying problems in lines, especially if there are flow volume changes along the line. The larger industrial sizes of switches are typically also used in heating, air conditioning and refrigeration applications in large buildings and commercial settings.

Smaller types can be used in any size of conduit, tubing or pipe. Each switch will be rated for minimum and maximum flow rates, measured in GPM or gallons per minute, as well as the correct temperature under which the switch will operate. It is important to check both the fluid temperature rating as well as the ambient temperature recommendations to ensure that the model of switch you select will function in the specific environment. The other key factor to note is the maximum pressure or PSI rating for the switch. Operating the switch in lines above the specified pressure may result in inaccuracy in the functioning of the switch.

Switches may be specific to a type of system. It is important to check the manufacturer's specifications and ensure that the switch you are considering is correct given the type of system you are installing. For example, a water line will need a one specifically for liquids with some manufacturers indicating water and liquids on their technical specifications. In addition the application information will let you know what it can be used for which may include alarms, motors, burners, metering devices, signal lights

Many of the water or liquid types of flow switches are made of brass and bronze and are very resistant to corrosion, rusting or breakdown. It is critical to ensure the correct installation of the switch, there is a in and an out side to most switches so that the valve will function correctly. Another common option for a lower cost but very durable type of flow control monitor is polypropylene. This lightweight yet extremely durable plastic is resistant to any type of rust, ideal for those lines that are not prone to freezing or expanding in very hot conditions. These newer styles of switches are becoming much more common on small and large projects since they come in a variety of sizes and ratings.