Storage Tank Monitoring
Storage tank monitoring is one of the most universal and safety-critical applications for pressure and level instrumentation. Every sector — from drinking water utilities and wastewater treatment to fuel storage depots, chemical processing plants, tank farms, and biogas facilities — depends on accurate, continuous tank level measurement for inventory management, overfill prevention, process control, environmental compliance, and safe operations.
Stork Solutions supplies a comprehensive portfolio of submersible level transmitters, screw-in level sensors, separable probe assemblies, plastic probes for chemically aggressive media, digital bus and SDI-12 level transmitters, HART®-enabled probes, pressure transmitters for pressurised tank headspace monitoring, differential pressure instruments, electronic pressure switches, and wireless transmitters — all engineered for reliable, long-term operation in the diverse range of liquids, environments, and hazardous area classifications that storage tanks demand.
With ATEX/IECEx intrinsically safe versions for explosive atmospheres, SIL 2 compliance for safety-instrumented functions, drinking water certifications (DVGW/KTW), and materials ranging from 316L stainless steel to titanium, PVDF, and 99.9% Al₂O₃ ceramic, Stork provides the right sensor for every tank, every medium, and every integration architecture.
Product Spotlight for Storage Tank Monitoring
Why Storage Tank Monitoring Demands Application-Matched Instrumentation
Storage tanks span an enormous range of media, sizes, pressures, and regulatory requirements. No single sensor suits every tank:
Media compatibility — Tanks may hold clean drinking water, aggressive wastewater, fuels, oils, solvents, acids, alkalis, slurries, viscous pastes, or biogas digestate. Wetted materials must be chemically compatible with the stored medium for the entire service life. Stainless steel suits most water and hydrocarbon applications; PVDF and specialist plastics are required for acids and aggressive chemicals; ceramic diaphragms resist fouling in wastewater and viscous media
Hazardous area classification — Fuel tanks, chemical tanks, and biogas digesters are classified as explosive atmospheres under ATEX/IECEx. All instruments in these zones must be intrinsically safe (Ex ia) to prevent ignition sources
Overfill prevention — Regulatory frameworks (including the UK Control of Major Accident Hazards Regulations and Dangerous Substances and Explosive Atmospheres Regulations) require independent overfill protection systems with SIL-rated instrumentation on tanks storing hazardous materials
Accuracy and range — Tank heights range from a few hundred millimetres (dosing tanks, sump tanks) to 25+ metres (large bulk storage). The instrumentation range must match, with accuracy sufficient for the inventory precision or process control requirement
Installation method — Open tanks accept suspended submersible probes; pressurised or sealed tanks require screw-in transmitters or external-mount pressure transmitters; some tanks have only narrow sounding pipes or limited access, requiring compact probes
Maintenance access — Separable (connectorised) probes allow sensor replacement without draining the tank or disconnecting the full cable run — a major benefit for deep tanks and tanks with difficult access
Multi-tank integration — Tank farms with dozens of tanks need digital bus integration (Modbus RTU, SDI-12) to minimise cabling and enable centralised monitoring from a SCADA/PLC or telemetry system
Remote and unmanned sites — Water reservoirs, borehole tanks, agricultural tanks, and remote fuel stores require low-power digital or wireless instruments with telemetry-ready outputs
Submersible Level Transmitters for Open Storage Tanks
Suspended submersible probes are the most common and versatile method for storage tank level measurement. Lowered to the tank base on a vented cable, they measure the hydrostatic pressure of the liquid column above the sensor diaphragm and output a calibrated level signal.
LMK 307 Stainless Steel Level Transmitter — 27 mm diameter, 4–250 mH₂O, flush-mounted ceramic sensor, 2-wire 4–20 mA / 3-wire 0–10 V, ATEX Ex ia, SIL 2 (IEC 61508/61511), good linearity and long-term stability. Stork lists drinking water systems, groundwater, stormwater, wastewater treatment, fuel storage, tank farms, and biogas plants as applications. SIL 2 compliance makes this suitable for safety-instrumented overfill protection on hazardous material tanks.
LMK 307 T Level and Temperature Transmitter — As LMK 307 with integrated temperature measurement. Dual level + temperature output from a single probe — essential for fuel and chemical tanks where temperature data is needed for volume correction (net vs gross volume), density compensation, and thermal expansion calculations.
LMK 306 Stainless Steel Level Transmitter — Ultra-compact 17 mm diameter, 6–200 mH₂O, 2-wire 4–20 mA. Fits through 3/4″ pipes. Stork lists open and closed tanks, drinking water abstraction, and groundwater monitoring. The 17 mm diameter makes this the choice for tanks with narrow access points, sounding pipes, or dip tubes where standard probes cannot be installed.
LMP 307 Stainless Steel Level Transmitter — 26.5 mm diameter, 1–250 mH₂O, 2-wire 4–20 mA / 3-wire 0–10 V, SIL 2, ATEX Ex ia, DVGW/KTW drinking water certified, petrol-version with welded sensor and housing. Stork lists drinking water, pump stations, water treatment, fuel storage, and tank farms. The petrol-version with welded housing eliminates internal leak paths — essential for fuel and hydrocarbon storage tanks. DVGW/KTW certification confirms suitability for potable water tank monitoring.
LMP 305 Slimline Level Transmitter — Compact slimline probe for installations requiring minimal intrusion. Suitable for dosing tanks, small process tanks, and confined spaces where a low-profile submersible probe is required.
LMK 382 Stainless Steel Level Transmitter — 39.5 mm diameter, 40 cmH₂O–200 mH₂O, 99.9% Al₂O₃ ceramic diaphragm, ATEX Ex ia, optional Pt 100 temperature element. Stork lists sewage, viscous and pasty media, fuel storage, tank farms, and biogas plants. The large ceramic diaphragm resists fouling and clogging from wastewater solids, sludge, and viscous fluids. Ideal for wastewater buffer tanks, sludge holding tanks, and biogas digesters.
LMK 387 Stainless Steel Level Transmitter — 22 mm diameter, 1–100 mH₂O, 99.9% Al₂O₃ ceramic, titanium housing option, ATEX Ex ia, DVGW/KTW drinking water cert, Pt 100 option. Stork lists wastewater, sludge, watercourses, fuel/oil, and biogas. The combination of 22 mm diameter and ceramic diaphragm makes this ideal for retrofit installations through 1″ pipes on existing tanks — particularly wastewater and fuel storage tanks that were not originally instrumented.
Separable (Connectorised) Submersible Probes for Maintenance-Friendly Tank Installations
Separable probes feature a detachable connector between the sensor head and the cable assembly. This allows the sensor to be replaced without removing or disconnecting the cable — a significant advantage for deep tanks, buried tanks, and tanks with restricted overhead access.
LMK 358 Separable Stainless Steel Level Transmitter — 39.5 mm diameter, 40 cmH₂O–100 mH₂O, capacitive ceramic sensor, detachable cable/sensor head, ATEX Ex ia, 99.9% Al₂O₃ diaphragm option. Stork lists wastewater, viscous media, fuel storage, tank farms, and biogas. The separable design is particularly valuable for biogas digesters and wastewater tanks where sensor fouling may require periodic replacement without draining the tank.
LMK 358 H Separable Stainless Steel Level Transmitter with HART® — As LMK 358 with HART® communication. HART® enables remote zero/span adjustment and diagnostics from the control room — essential for tank farm installations where access to individual tanks for manual calibration is time-consuming and requires confined-space entry permits.
LMP 308 Separable Stainless Steel Level Transmitter — 35 mm diameter, 1–250 mH₂O, detachable cable/sensor head, SIL 2, ATEX Ex ia. Stork lists groundwater, wells, rain spillway basins, containers, water treatment, and water recycling. SIL 2 compliance with separable construction — combining safety-instrumented capability with maintenance convenience for tank farms with SIL-rated overfill protection.
LMP 308 i Separable Stainless Steel Level Transmitter Precision — Precision version of LMP 308 with enhanced accuracy for high-value inventory measurement. Where tank contents are expensive (fuel, chemicals, pharmaceutical intermediates), the precision version reduces stock discrepancy and improves inventory reconciliation.
Plastic Level Transmitters for Chemically Aggressive Storage Tanks
For tanks storing acids, alkalis, aggressive solvents, and other media that attack stainless steel, plastic-bodied level transmitters with PVDF or specialist polymer wetted parts provide long-term chemical resistance.
LMK 806 Plastic Level Transmitter for Aggressive Media — Plastic housing, designed for chemically aggressive liquids. Suitable for acid storage tanks, chemical dosing tanks, and effluent tanks where metallic probes would corrode.
LMK 807 Plastic Level Transmitter for Aggressive Media — Plastic construction for aggressive media. Provides continuous level measurement in tanks holding aggressive chemicals, wastewater with high chemical load, and industrial effluent.
LMK 808 Separable Plastic Level Transmitter — Separable plastic probe with detachable connector. Combines chemical resistance with maintenance-friendly separable construction — the sensor can be replaced without disconnecting the cable, reducing downtime and chemical exposure during maintenance on aggressive media tanks.
Screw-In Level Transmitters for Sealed & Pressurised Storage Tanks
Where tanks are sealed, pressurised, or where a permanent threaded connection at the tank base or side wall is preferred over a suspended probe.
LMK 331 Screw-In Level Transmitter — 400 mbar–60 bar, semi-flush G 3/4″ sensor, PVDF pressure port option, ATEX Ex ia, SIL 2. The screw-in format provides a clean, vibration-resistant installation without suspended cables. SIL 2 compliance enables use in safety-instrumented overfill protection on pressurised chemical and fuel tanks.
LMK 351 Screw-In Level Transmitter — 40 mbar–20 bar, capacitive ceramic flush-mount, 99.9% Al₂O₃ diaphragm option, PVDF pressure port, ATEX Ex ia. The flush ceramic sensor prevents clogging from viscous media, slurry, or high-solids wastewater. PVDF option extends service life in acid and solvent storage tanks.
LMP 331 Screw-In Level Transmitter — Screw-in piezoresistive level transmitter for pressurised tanks and process vessels. Robust threaded connection resists vibration and pressure cycling in industrial storage environments.
LMP 331 i Precision Screw-In Level Transmitter — Precision version with enhanced accuracy. For high-value chemical and pharmaceutical intermediate storage where precise inventory measurement reduces stock variance and supports batch reconciliation.
Digital Level Transmitters for Multi-Tank Networks & Telemetry
Tank farms, water treatment works, and distributed storage sites with multiple tanks benefit from digital bus integration — reducing cabling cost and enabling centralised monitoring from a single SCADA/PLC or telemetry gateway.
DCL 531 Stainless Steel Probe with RS485 Modbus RTU — 26.5 mm diameter, 1–250 mH₂O, RS485 Modbus RTU, ≤ ±0.25% FSO, 500 Hz measuring rate, IP68. Multi-drop Modbus allows a single RS485 trunk to connect all tanks in a farm, dramatically reducing cabling cost and installation time. Each sensor is individually addressable for tank identification.
SLS-A Submersible Level Transmitter – Analogue Output — Analogue output submersible probe designed for environmental monitoring and water storage applications. Suitable for remote water tanks, reservoirs, and rainwater harvesting installations where a simple, reliable analogue signal feeds a data logger or telemetry unit.
SLS-D Digital Submersible Level Transmitter – SDI-12 — SDI-12 digital output, level + temperature via single interface. SDI-12 is the standard digital protocol for environmental and water industry data loggers. Multi-drop capability allows multiple tank sensors on a single SDI-12 bus, ideal for remote water storage, reservoir networks, and agricultural tank monitoring with solar-powered telemetry.
SLS-LC Submersible Level Transmitter – Ceramic Sensor — Ceramic sensor variant for enhanced media compatibility in slightly contaminated water, wastewater storage, and treated effluent tanks where a ceramic diaphragm resists fouling and chemical attack.
HART®-Enabled Level Transmitters for Remote Configuration & Diagnostics
HART® communication over the standard 4–20 mA loop enables remote zero/span adjustment, diagnostics, and configuration from the control room — essential for large tank farms where access to individual tanks is restricted.
LMK 382 H Stainless Steel Level Transmitter with HART® — As LMK 382 with HART® communication. Remote calibration and diagnostics for wastewater, fuel, and chemical storage tanks without requiring tank entry or confined-space permits. HART® also enables asset management systems to track sensor health and predict maintenance.
LMK 387 H Stainless Steel Level Transmitter with HART® — As LMK 387 with HART® communication. 22 mm diameter with HART® — retrofit-friendly with remote configuration for existing tank installations upgraded to digital asset management.
Pressure Transmitters for Pressurised Tank Headspace & Blanket Gas Monitoring
Pressurised storage tanks (nitrogen-blanketed chemical tanks, LPG bullets, pressurised water tanks) require headspace pressure monitoring in addition to level measurement.
DMK 331 P Industrial Pressure Transmitter — Capacitive ceramic sensor, flush diaphragm, ATEX Ex ia, 40 mbar–40 bar. For monitoring nitrogen blanket pressure, tank vapour space pressure, and inert gas padding on chemical and fuel storage tanks. Ceramic sensor resists corrosion from tank vapours.
DMK 351 P Pressure Transmitter for the Process Industry — Capacitive ceramic sensor, flush diaphragm, 100 mbar–40 bar, ATEX Ex ia, HART®, SIL 2. For safety-instrumented tank headspace pressure monitoring where blanket gas failure or over-pressurisation is a safety concern. SIL 2 + HART® enables integration with safety PLCs and remote diagnostics.
DMP 331 P i Precision Pressure Transmitter — Flush diaphragm, ≤ ±0.1% FSO, ATEX Ex ia, SIL 2, 100 mbar–40 bar. Precision headspace pressure measurement for high-value chemical storage where tight pressure control prevents product degradation, maintains inert atmosphere integrity, and satisfies COMAH/DSEAR regulatory requirements.
Electronic Pressure Switches for Tank Overfill & Low-Level Alarms
Independent hardwired switching for critical tank safety alarms — operating independently of the control system PLC to provide defence-in-depth overfill protection and low-level pump protection.
DS 200 Electronic Pressure Switch — 100 mbar–600 bar, up to 4 PNP contacts, 4–20 mA output, LED display, ATEX Ex ia. Configurable for high-level alarm (overfill prevention), high-high-level trip (independent safety shutdown), low-level alarm (pump protection), and tank pressure exceedance alarm.
DS 201 Electronic Pressure Switch — 400 mbar–600 bar, ceramic sensor, ATEX Ex ia, PVDF pressure port option. Ceramic sensor resists fouling in wastewater and chemical tanks. PVDF port extends service in acid storage.