The float valve began as a hinged flap patented in 1778 by Joseph Bramah of Yorkshire, England. It replaced the slide valve commonly seen on toilets, but began revolutionizing water maintenance across various applications. This system has been refined and redeveloped for the past two hundred years, and the concept has proven to be simple and reliable. But despite it’s reliability, computer innovations began to create a demand for more accurate and interactive technologies, creating the float switch. This technology took standard mechanical floats and added an electrical component so that they could be remotely monitored and controlled.

Theory of operation
The float level sensor is a device that can incorporate several different configurations. They all are based on the principal that there is a floating segment of the sensor that moves up and down as the liquid level rises and falls. This in turn is connected in some manner to a switch that then closes or opens to indicate the level of the liquid. These sensors can be supplied in a variety of switch configurations (SPST, SPDT, DPST, DPDT, etc.).

Design Challenges
The float sensor needs to be designed in such a manner that the float portion is allowed to move freely and have less density than the liquid being detected. Also the switching contacts need to be sealed from contamination. The switch contacts need to be designed to handle the voltage and current requirements required.

Advantages
The float sensor is generally less expensive that other sensor types. It can be designed to safely handle high voltages and currents. The output of the float sensor is either a closed or open switch thus generating an output that is immune to external noise sources and can be wired to directly control valves, small motors, and other devices.

Disadvantages
If multilevel detection is required, then multiple float sensors need to be purchased and installed. Depending on the detection requirements, the use of multiple float sensors may require the use of a control unit that can function as an intelligent device in order to provide the required outputs for control. The float sensor is also subject to fouling from debris and pitting of the switch contacts. If multiple float sensors are required, then multiple mounting locations on the tank will also be required.
The issue with float valves is that the facility manager MUST go and look at the system where the float valve is installed. There is no way to electrically bring these connections to a centralized control or monitoring system. This requires more time, money and effort to manager the water level in these environments. WaterLine Controls™ allows the operator to save money, time and energy by centralizing the monitoring of water level in different environments like, Boilers, Cooling Towers and sumps in large commercial facilities. It is also common for the lift arm, valve gasket, or float itself to become damaged over time and require replacement. Our WLC Series units have a 15 year averproduct age duty life cycle, and our stainless steel sensors never plate, foul or deteriorate.

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