Fuel Float Sensors With Multiple Sense Points REED RELAYS REED SENSORS REED SWITCHES Introduction All trucks and automobiles currently utilizing internal combustion engines have fuel tanks. To the driver of the fueled motor vehicle, one of the most important instruments on his front panel is his fuel gage. It is important that the gage provides an accurate reading of the fuel level. To properly measure the fuel, some form of instrument must exist inside the fuel tank. To survive this environment and make accurate measurements is not an easy undertaking. To supply the reliability and assurance of accurate fuel readings, Reed Sensors are being widely used because they operate reliably and accurately, while presenting an economical solution. Figure 1. Diagram of fuel float sensor Features • Ability to activate and control switching up to nine switching points • Hermetically sealed • Ability to work under very hot and cold temperatures as normal operation • Ability to withstand very toxic chemical atmosphere without any material degradation • Dynamically tested contacts • Reliable switching • Designed to handle high shock environments • Millions of reliable switching operations Figure 2. Sensor Physical Layout and Schematic Diagram Applications • Fuel monitoring systems • Ability to monitor any liquid level particularly when multiple point monitoring is required MEDER’s New Fuel Fuel Float Reed Sensors Sensors Offer Multiple Monitoring Positions To Give Accurate Fuel Levels. MEDER has developed a new float series having up to nine sensing points over a 300 mm sensing distance. These sensors are being designed into fork lifts, front end loaders, and various construction vehicles. These sensors are designed to withstand potential deterioration caused by exposure to the chemically active ingredients in gasoline (petro). The tube is made of stainless steel (see Figure 2) and the float that rides up and down over the tube is made of Nitrile Butadiene Rubber (NBR). This NBR is a special plastic designed to be impervious to oil, fuel and maintain its excellent features under high temperatures. These features include stable resistance to temperature, the ability to maintain buoyancy, chemical resistance to these liquids, mechanical strength, shock resistance and no changes in dimensional characteristics. The LS Sensor Series can have anywhere from two up to nine sensing points. Each sensing point has a resistor in series, setting up a resistor network. As the float moves over the sensor tube, Reed Switches will be sequentially activated, changing the resistance in the resistor network. This change in resistance is then converted into an accurate depth measurement of the fuel. MEDER electronic Application MEDER electronic AG | Germany | tel.: +49(0)7731/8399-0 | Email: [email protected] MEDER electronic Inc. | USA | tel.: +1 508.295.0771 | Email: [email protected] Page 1 of 2 www.meder.com Fuel Float Sensors With Multiple Sense Points REED RELAYS REED SENSORS REED SWITCHES Specifications (@ 20° 20°C) KSS S Series KS Operate specs Min Max Units Must close distance ref ref mm Must open distance ref ref mm Hysteresis Load Characteristics Switching voltage Switching current Carry current Contact rating Static Contact resistance Dynamic contact resistance Breakdown voltage Operate time Release time Operate Temp Storage Temp Min Max Units 200 0.5 1.25 10 250 V Amps Amps Watts mΩ With the requirement of different switching points for different vehicles it can be costly to have a different sensor for each different number of switching points. MEDER’s engineering team took this into consideration during the sensors initial design concepts and found a way to come up with a “one design” approach that can generate multiple switching points. This approach basically eliminates the need for new tooling for each different sensor length. Using Reed Switches for each sensing point guarantees reliable operation. Because the Reed Switch has excellent repeatability, It insures accurate operate points are achieved over the life of the sensor. These repeatable operate points are also achieved over the entire operating range from -10°C to 90°C. These construction and/or warehouse vehicles are usually in use for 15 to 20 years. So accuracy and reliability are critical. These Reed Sensors are designed to give fault free operation for 10’s of millions of operations. Consult our engineering group with your specific applications. Liquid Level Series 250 225 0.5 0.1 -10 90 -20 90 mΩ V msec msec °C °C Series KSSKSS-BV50860 BV50860 LS01 LS02 LS03 Dimensions mm Illustration inches W 29.0 1.142 H 29.0 1.142 L W H L W H L 327.0 19 24 42 19 24 75 12.874 0.748 0.945 1.654 0.748 0.945 2.953 W 25 0.984 H 25 0.984 L 80 3.150 Adaptable Liquid Level Series Series LS04 LS05 Dimensions mm Illustration inches W 25 0.984 H 25 0.984 L 165 6.496 0.2760.630 0.2760.630 3.15078.740 W H L 7-16 7-16 802000 **Consult the factory for more options not listed above. ** MEDER electronic Application MEDER electronic AG | Germany | tel.: +49(0)7731/8399-0 | Email: [email protected] MEDER electronic Inc. | USA | tel.: +1 508.295.0771 | Email: [email protected] Page 2 of 2 www.meder.com