I need a corrosion resistant liquid level sensor to measure up to 2m. We are looking to use the sensor in a Chlorine stock solution tank. Chlorine concentration is approximately 0.6% (6000ppm). Temperature is approximately 35C?
For the most robust and chemical compatible solution, we suggest the LMK 809 for your application to meet your technical requirements. The LMK809 has a high-grade ceramic sensor which is virtually chemically inert, PVDF housing and a FFKM (Chemraz®) seal. The cable is FEP which is similar to PTFE, making this a chemically compatible level solution.
LMK 809 Corrosion Resistant Submersible Level Transmitter
- SKU ID: s1-lmk809-0014
- Pressure Range: 0 – 2mWG
- Output Signal: 4-20mA, 2 wire
- Accuracy: 0.35% FS
- Installation Type: Submersible probe with flush diaphragm
- Housing Material: PVDF
- Diaphragm Material: Ceramic Al2O3 99.9%
- Media Exposed Seals: FFKM
- Cable Type: FEP (70degC max)
- Cable Length: 5m
This application highlights the material selection challenges faced when measuring liquid levels in aggressive chemical storage tanks. Specifically, it details the configuration of a submersible hydrostatic level transmitter for a chlorine stock solution. To prevent sensor degradation and failure caused by the corrosive nature of the media, the solution utilizes a combination of specialized chemically inert materials.
- Application: Level measurement of Chlorine stock solution (6000ppm).
- Critical Constraint: High corrosion potential requiring non-metallic wetted parts.
- Sensor Technology: Ceramic Al2O3 99.9% capacitive sensor.
- Protective Materials: PVDF housing, FFKM seals, and FEP cabling.
The requirements for this application centre on the accurate level measurement of a chlorine stock solution within a storage tank. The concentration of the chlorine is approximately 0.6% (6000ppm), maintained at a process temperature of roughly 35°C. Chlorine is a highly aggressive oxidizer, meaning that standard stainless steel submersible sensors, which typically function well in water or mild fluids, would suffer rapid corrosion and eventual failure in this environment. The application requires a measurement range of up to 2 meters. Therefore, the primary engineering challenge is selecting a sensor configuration where every wetted component, housing, diaphragm, seal, and cable, is chemically compatible with the media to ensure longevity and measurement stability.
To address the corrosive nature of the application, the LMK 809 series submersible level transmitter is selected due to its specialized non-metallic construction. Instead of standard stainless steel, the probe housing is manufactured from PVDF (Polyvinylidene Fluoride). PVDF is a high-purity engineering plastic chosen specifically for its excellent chemical resistance to oxidants like chlorine, ensuring the structural integrity of the probe remains intact during long-term submersion. The sensing element itself utilizes a high-grade Ceramic Al2O3 99.9% diaphragm. Unlike metallic diaphragms which can pit or corrode, high-purity ceramic is virtually chemically inert and provides a flush surface that resists fouling, maintaining high accuracy (0.35% FS) even in aggressive measuring tasks.
Beyond the housing and sensor, the integrity of the watertight seal is the most critical failure point in submersible chemical applications. Standard elastomers like Viton or NBR are often insufficient for chlorine exposure. Consequently, this solution employs FFKM (perfluoroelastomer) seals, which offer near-universal chemical resistance and maintain a pressure-tight seal preventing liquid ingress into the electronics. The final component of the assembly is the cable; a standard PVC or PUR cable would degrade over time in this solution. An FEP jacketed cable is utilised instead, providing properties similar to PTFE, including high thermal resistance and immunity to the chemical attack of the 6000ppm solution. To cover the required 2-meter measuring depth, a pressure range of 0 to 0.2 bar (equivalent to 2 mH2O) is specified, providing ample coverage for the tank height.
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Contact us about this 2m range 0.6% conc. chlorine liquid level sensor page to request more information, or to discuss your application requirements.