The management of fluid levels within electrophoretic painting (ELPO) tanks presents significant technical hurdles due to the viscous and chemically aggressive nature of the wastewater. This application story details how a specialized level measurement solution, utilizing high-purity ceramic sensors and flush-mounted designs, ensures operational reliability in automotive manufacturing environments.
- Preventing sensor fouling in pasty media with flush-mounted diaphragm technology.
- Utilizing high-purity 99.9% Al2O3 ceramic for superior chemical resistance in paint plant effluents.
- Implementing PVDF process connections for long-term stability in corrosive surfactants.
- Maintaining accurate hydrostatic readings in deep-tank automotive wastewater applications.
In the automotive manufacturing sector, the electrophoretic painting (ELPO) process represents a demanding environment for instrumentation due to the presence of wastewater saturated with paint solids, surfactants, and various chemical residues. These constituents often create a viscous and pasty medium that can quickly compromise standard measurement devices. In this specific installation involving a forty-foot tank, the primary challenge was to maintain accurate hydrostatic level readings while preventing the build-up of residues that typically clog recessed pressure ports. The fluctuating chemical composition of the effluent also required a high degree of material inertness to prevent corrosion and sensor degradation over time.
To address these challenges, the solution centered on the LMK 351 series, a screw-in transmitter utilizing a capacitive ceramic sensor element. The selection of a flush-mounted diaphragm was critical, as it eliminates the cavities where paint solids could accumulate, thereby ensuring the sensing surface remains in direct contact with the media without obstruction. To withstand the aggressive chemical nature of the ELPO residues, the configuration utilized a 99.9% high-purity Al2O3 ceramic diaphragm. This higher purity alumina provides enhanced resistance to the specific chemical cleaners and surfactants used in the painting process compared to standard industrial-grade ceramics, which typically use 96% purity.
The mechanical integrity of the installation was further reinforced by selecting PVDF for the process connector. This fluoropolymer offers excellent chemical compatibility with the organic solvents and acidic or alkaline components often found in car paint plant wastewater. By combining a robust capacitive sensing principle with chemically resistant materials, the system provides a stable 4-20mA output signal, ensuring precise integration into the plant’s control architecture. The resulting installation offers high overpressure capability and long-term signal stability, significantly reducing the maintenance requirements typically associated with level monitoring in pasty and aggressive industrial fluids.
LMK351 Flush Ceramic Diaphragm Level Transmitter with PVDF Connection
- Part Number: 470-1601-1-3-TA0-M00-1-B-C-000
- Pressure Range: 0 to 1.6 bar (approx. 53.5 ftH2O)
- Output Signal: 4-20mA / 2-wire
- Accuracy: 0.35% FSO
- Electrical Connection: IP67 seal with 2m of PVC cable
- Process Connection: G1 1/2 male DIN3852 with flush diaphragm
- Media Exposed Seals: FKM
- Process Connector Material: PVDF
- Diaphragm Material: Ceramic Al2O3 99.9%
- Special Version: Standard