FFSMC10B Datasheet/PDFFloat Level Sensors
Application Field
Float level sensors, or sometimes referred to as float switches, are generally used in the measurement and control of liquids and may be connected to alarms, valves, or pumps. Float switch works by detecting the vertical movement of a float when its buoyancy changes due to liquid levels. The switch action is triggered when the float reaches a predetermined height, causing the switch to open or close an electrical circuit.
Float level sensors are typically used for controlling water level in tanks or reservoirs, detecting high/low liquid levels, or providing a sensing point in liquid for drain waste. These sensing devices can be used in a wide variety of markets including; pumps, waste water, laundries, beverage, and chemical. Additionally, the use of a float switch as an automatic level controller is beneficial in two ways. One, the pump switch is automatically activated when the tank is filling and deactivated when the desired water level is attained. Two, it continuously regulates water levels, avoiding overflows or depletions.
Working Principle
Float level sensors are typically built from thermoplastic or polymer materials to allow in-line mounting. The devices work on the principle of buoyancy, which is determined by the density of the liquid. A float, attached to an electrical contact, is positioned within the water storage or process tank, so that when the water level starts to rise, the buoyancy of the float acts upon the contact arm. This in turn causes the electrical contacts to close or open, activating a voltage to be delivered to a control device.
The sensor functions by monitoring a conductive metal float mounted to an arm. It is filled with a liquid that has the same specific gravity as the liquid that the sensor is immersed and which the float should be monitoring. As the liquid level rises, the float attached to the arm rises with the liquid, in turn turning an internal switch on or off. The moment the liquid level reaches the point where the internal switch is activated, the level sensor sends a signal to the switch telling it to turn on, thereby activating the associated control circuits.