Flow switches are valuable in a range of applications as they are designed to control the flow of liquids or gases through a designated channel. This means that flow switches can be used to monitor flow rates of liquids, which in turn works to protect pumps and trigger alarms if the flow rate is too high or too low. But, the benefits of flow switches doesn’t just stop there.
Read on to find out how you can keep your application on track with a flow switch, whilst negating the impact of costly downtime due to pump breakdowns caused by over or under flow rates.
What is a flow switch?
Flow switches are a highly versatile switch that is often used in fluid control applications. This innovative and versatile switch can be utilised in a wide array of applications and works to perform a number of functions, working to monitor the flow rate of a liquid. The flow switch will then trigger an alarm if the flow is too high or even too low in order to protect the pump.
Flow switches trigger an alarm by sending an electronic signal to a PLC or electronic controller to highlight the issue to the team, who will step in to respond.
What does a flow switch do?
To understand exactly what a flow switch does in practice, you must first understand the inner workings of a flow switch and how it works in principle.
Most, although not all, flow switches consist of a paddle or some form of magnetic trigger that connects to a circuit. Here, the flow switch is installed in the channel through which the gas or liquid passes, which causes the paddle to rotate or be displaced, which then sends an electronic signal to a transducer.
The transducer works to convert this signal into a reading that is sent to the transmitter, at which point the transmitter measures the reading against predefined parameters before performing the required action that has been previously specified. These actions can consist of a number of different responses, including sounding an alarm, shutting off elements of the system, or even diverting the flow altogether. Therefore, a flow switch can monitor and control the flow in either a designated section of piping or even across the whole system.
Although, as was mentioned earlier, some flow switches don’t have a physical paddle, such as ultrasonic flow switches. This type of flow switch instead bounces a signal off the monitored media, either a gas or liquid. Ultrasonic flow switches are particularly useful in applications that require no moving parts, such as for hygiene or maintenance purposes. This type of flow switch is also used in areas with contaminated or hazardous materials, which makes them particularly suited to petrochemical applications.
Which applications suit a flow switch?
Flow switches are used in a variety of applications, particularly in applications that require them to operate fully automatically. Some common examples of flow switch applications are:
- Boilers – Flow switches are used on both water and gas pipelines and are used to protect the boiler from operating in low or no flow states.
- Shower pumps – A flow switch is used to maintain water pressure being sent through the piping and out of the shower head.
- Heat pumps – Often used in swimming pools and spas, heat pumps bring the water up to the desired temperature and works to stop the pump from operating if the water supply is interrupted.
- Pool pumps – Perform very similarly to heat pumps, in which a flow switch is used to prevent the pool pump from being run in low or no flow situations.
- Hot tubs and Jacuzzis – Flow switches are used in these applications to prevent damage to the pump components caused by overheating if the flow rate is too low.
- Chillers – Flow switches are used in chiller solutions to protect against low or no flow situations that can ultimately lead to freeze damage. These switches are either liquid or gas, depending on the compression system being used.
Additionally, flow switches can be used in sanitary and hygienic applications, in which hygiene is very important. These applications may include food production, pharmaceutical manufacturing, medical and laboratory environments as well as industrial development in which it is important to keep contamination to a minimum. Flow switches for these applications are often made of stainless steel, often with sealed-off chamber housing or magnetic switches to prevent the impact of cross contamination.
Flow switches are also well suited to high-temperature and high-pressure applications, particularly in industrial and manufacturing systems in which continuous flow of liquid and gases need to be maintained. This style of flow switch is designed and built for use in challenging environments where the flow switch is subjected to greater forces and flow rates.
How to install and test a flow switch<
As there are so many different types of flow switch available, there are also an array of flow switch installation methods. To establish how you need to install a flow switch, it is important to have a clear understanding of which type of switch you are using and what its purpose is. The basic rules of thumb when installing a flow switch are:
- Place on a straight section of pipe
- Ensure there is equivalent to 10x the pipes diameter before and after the switch
- Avoid fitting near to a bend or obstruction.
To test a flow switch, you will often be able to see that a flow switch is working by simply observing it in action and checking that the correct responses are triggered when flow stops or starts. In other cases, an ohmmeter may be needed to measure the resistance of the switches resistance. It is important to regularly check and test your flow switch to ensure that your system is able to continue functioning without the impact of costly downtime caused by breakages.
Placing a flow switch in an application
Where you put a flow switch in your application does largely depend on the type of switch you have opted for, and the application itself. Despite this, it is important to consider some vital points when installing a flow switch in your application.
The most important thing to consider at this time is where the flow switch will be installed. It is important to install flow switches on a straight section of the pipe, with the equivalent of ten times the pipe’s diameter in front and behind the switch. It is also vital that you avoid bends or other fittings that will cause flow rate fluctuations due to the obstruction.
Keep your application on track with flow switches
Installing a flow switch is a simple way to be able to control the flow of a gas or liquid through a channel, monitoring and controlling media to prevent spillages or uncontrolled flow that can ultimately cause costly damage to the system. This is why flow switches are a straightforward way to keep your application on track!
