Cognesense - Measure, Monitor, Protect

MCG 351

Terminal operations managers, custody transfer officers, process engineers, and EPC specifiers require accurate averaged temperature data to support corrected volumes, inventory reporting, and regulatory compliance.

The MCG 351 Average Temperature Probe delivers this with ±0.25 °C accuracy using 1 to 16 platinum RTD elements spaced along the probe length. Unlike single-point sensors that can create measurement errors in stratified tanks, the MCG 351 automatically identifies which RTD elements are submerged and computes a true averaged temperature, aligned with API MPMS requirements for legally defensible custody transfer.

Built for harsh storage environments, the probe features:

A flexible 316 stainless steel armored hose
Hermetically sealed conductors for long-term corrosion resistance
An anchor weight to maintain vertical stability in tall tanks

The probe supports both standard and high-temperature applications, from chilled chemicals to hot asphalt.

When paired with the MCG 2350 Average Temperature Converter, the probe becomes intrinsically safe and integrates seamlessly with L&J and Cognesense tank gauging systems.

The result is a reliable solution engineered for accuracy, compliance, and long-term durability across a wide range of tank types and operating environments.

MCG 351 Average Temperature Probe

Details

The MCG 351 is designed for applications where vertical temperature variation inside tanks can significantly affect inventory accuracy and custody transfer calculations.

By distributing multiple RTD elements along the probe length, the system measures temperature across the product column. The converter then determines which sensors are immersed in product and calculates a true average temperature, eliminating errors caused by stratification or temperature layering.

This approach ensures dependable temperature data in both shallow and very deep storage tanks.

Applications

Custody Transfer Correction: Provides accurate averaged temperature data required for converting observed volume to corrected volume, helping prevent custody disputes.
Refined Product Terminals: Corrects for temperature layering in gasoline, diesel, jet fuel, and additives, maintaining billing accuracy.
Crude Oil Storage: Detects stratified layers common in large crude tanks, improving mass balance accuracy and audit compliance.
Chemical Storage Tanks: Supports temperature-sensitive density and quality calculations for specialty chemicals and regulated processes.
High-Temperature Applications: Handles hot asphalt, heavy fuel oils, and other demanding products with probe options rated up to 204 °C (400 °F).
Very Tall Vertical Tanks: Supports up to 16 RTD elements and probe lengths up to 82 feet, ensuring accurate temperature data in deep tanks where single-point probes cannot provide reliable readings.

Technical Specifications

Parameter

Specification

Accuracy

±0.45 °F (±0.25 °C)

Temperature Range

Standard: –58 °F (–50 °C) to +215 °F (+102 °C)

High Temperature Option

–58 °F (–50 °C) to +400 °F (+204 °C)

Construction

316 stainless steel flexible hose

Wiring

Hermetically sealed lead wires for corrosion resistance and long-term stability

Pressure Rating

Hose assembly tested to 171 psig

Insulation Test

600 V RMS, resistors to housing

RTD Elements

1 to 16 platinum RTD elements depending on tank height (2 ft to 82 ft)

Process Connections

Standard ¾″ NPS or 1″ NPS

Additional Connections

Optional NPS, NPT, and ANSI flanged connections

Safety

Intrinsically safe when paired with the MCG 2350 converter

Mounting

Anchor weight included for vertical stability

Compatible Equipment

MCG 2350 Average Temperature Converter

Integration

Compatible with Cognesense servo gauges, radar gauges, and tank gauging transmitters

2026 COST ESTIMATE

Support

If you have a question that we have not covered, please contact support and we will be happy to assist.

Why is it important to measure average temperature instead of a single-point temperature?

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Liquids in large tanks often have temperature stratification, meaning the temperature varies at different levels. A single-point measurement can be misleading and lead to significant errors (up to ±0.5%) in volume correction and inventory calculations. The MCG 351’s multiple elements provide a true average, which is required by global standards for accurate custody transfer and compliance.

Is the MCG 351 compatible with other tank gauging systems?

The MCG 351 is designed to work seamlessly with L&J’s gauges and transmitters. It is typically paired with the MCG 2350 Average Temperature Converter, which takes the multi-element input and provides a digital output that can be integrated with various host systems.

How is the MCG 351 protected for hazardous-area use?

The MCG 351 is built with an intrinsically safe design, meaning it operates at a low-energy level that is insufficient to ignite a flammable atmosphere. When connected to the MCG 2350 converter, which contains a critical intrinsic safety barrier, the probe meets global approvals like UL, C-UL, ATEX, and CE for safe use in hazardous environments.

How does the probe determine which temperature elements to include in the average?

The connected transmitter automatically identifies submerged RTD elements and averages only those values, producing an accurate, real-time average temperature.

What types of tanks can the MCG 351 be used in?

It is suitable for crude oil tanks, refined product terminals, large chemical tanks, floating-roof tanks, cone-roof tanks, and high-temperature asphalt tanks.

Is the probe durable enough for corrosive or heavy products?

Yes. The stainless-steel hose and hermetically sealed wires withstand corrosive fluids, heavy oils, and challenging tank atmospheres.

What is the maximum probe length available?

Up to 82 ft in standard configurations, with lengths matched to tank height. Longer custom lengths are available upon request.