MultiMulti-Point Hot Fluid Level Sensor REED RELAYS REED SENSORS REED SWITCHES Introduction There are several laboratory fluid systems that required fluid level monitoring to help control very elaborate equipment processes. This new float sensor has four sensing positions, three of which are dedicated to monitoring hot fluid levels, and the fourth to sense a low fluid level cutoff point. The fourth sensing point is for safety reasons. It insures that heating coils are never exposed above the fluid level, which could set up a very dangerous situation. Figure 1. On the left the full sensor is shown and on the right the black casing is removed Features • Ability to operate at very hot temperatures up to 200°C as the normal operating environment • Meets EU WEEE directive 2002/96/EC • Meets RoHS directive 2002/95/EC • Designed to work in hot and cold liquid temperatures • Hermetically sealed • Dynamically tested contacts • Reliable switching Figure 2. Showing a full and low tank with LED indicator • Millions of reliable switching operations M EDER Once Again Leads the Way Developing Specific Float Sensors Sensors Solving Full Solution Requirements Applications • Single and multipoint liquid level sensing for an assortment of liquid systems running either hot and/or cold fluids Often, designing a sensing system, requires more than ‘off the shelf’ solutions. More and more applications require unique component development specific to a given set of circumstances. In this application, the sensor must operate at extreme temperatures where the o float and magnet must withstand operating temperatures as high as 200 C. MEDER’S approach has been to use only the most reliable materials that have demonstrated their quality and reliability in the field for the life of the system. The magnet and stainless steel float are attached by a stainless steel rod, (see Figure 2). The magnet/rod are captured in a plastic sleeve. The PCB is immediately outside this plastic sleeve and senses the movement of the float and magnet. In this manner the four detection points are monitored. The fluid levels will naturally increase as the liquids are heated and expand; and conversely, the fluid level will decrease as the fluid bath temperature cools. Evaporation of the fluids can also occur, particularly at the higher temperatures, potentially reducing the liquid levels. Most reed sensor offerings supply only the reed sensor. MEDER’s new design encompasses it all – the reed sensor, the float, and the magnet along with a PCB and its associated circuitry. This saves the designer a valuable amount of time by only having to specify and qualify one component. They no longer have to work with several different suppliers and coordinate between them. 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 MultiMulti-Point Hot Fluid Level Sensor REED RELAYS REED SENSORS REED SWITCHES Specifications (@ 20° 20°C) LSS Series Operate specs Min Max Units Must close distance Ref Ref mm Must open distance Ref Ref mm Hysteresis Load Characteristics Min Max Units Switching voltage Switching current Carry current Contact rating Static Contact resistance Dynamic contact resistance Breakdown voltage Operate time Release time Operate Temp (float and magnet) Storage Temp 200 0.5 1.0 10 150 V Amps Amps Watts mΩ 200 mΩ Since this sensor requires some electrical circuitry, using a printed circuit board with plated thru solder holes guarantees reliable connections using an automated wave soldering systems. The hermetically sealed reed switches are properly placed and positioned in their predetermined sensing locations. Another critical element is the acknowledgement that during assembly, problems can occur. MEDER tests all sensors 100% for all operating conditions, but in addition, tests for dynamic contact resistance (DCR). Essentially this test is a guard against the many faults that can occur during assembly. If the reed contacts have any internal contaminations; or the reed capsule has been stressed or a slight crack has occurred, the DCR test will detect these conditions and reject the sensor. This testing is carried out in an automated testing system. MEDER’s design for manufacturing approach provides a long reliable life in the field. Consult our engineering group with your specific applications. Adaptable Liquid Level Series Series Series 200 -10 V 0.6 msec 0.05 msec 200 °C -25 75 °C KSSKSS-BV15178 LS04 LS05 Dimensions mm Illustration inches W 25 0.984 H 25 0.984 L 165 6.496 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 Liquid Level Series Series LS01 LS02 LS03 Dimensions mm W 19 H 24 L 42 W 19 H 24 L 75 W 25 Illustration inches 0.748 0.945 1.654 0.748 0.945 2.953 0.984 H 25 0.984 L 80 3.150 **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