One of the world’s largest oil and natural gas exploration and production companies was using a competitor’s thermal mass flow meter in a flare gas application. The operation’s harsh upset conditions frequently damaged the meter’s fragile sensor, and the company challenged Sage Metering to solve the problem. Sage Metering developed a new sensor and probe that resolved this client’s issue.

Challenge: Measuring Flare Gas in Upset Conditions

Measuring Flare Gas in Upset Conditions Just got Easier
Is your thermal mass flow meter’s sensor breaking in upset conditions?

We use flare gas systems to burn off waste gases and dispose of surplus gases, which protect people, the environment, and equipment.  Measuring and monitoring flare gas are necessary to ensure the flare system is functioning correctly. Additionally, environmental regulations often require the measurement of flare gas emissions. However, there are some inherent challenges associated with determining flare gas flow, one of which is extreme flow variation. We discuss these problems at length in our white paper, Flare Gas Measurement Using Sage Thermal Mass Flow Meters.

A major oil and gas producer used a competitor’s thermal mass flow meter to determine flow in a facility’s flare header. During upset flow conditions, at high gas flow rates, however, the meter’s sensor was frequently damaged. We speculate that during upset conditions, either ice in the flare line or debris build up inside the pipe loosened, broke off, damaging the fragile ½ inch flow sensor probe.

Solution: Heavy-duty ¾” Sensor & Probe

rugged thermal mass flow sensor
Pictured above are both the 1/2″ Sage sensor (L) and 3/4″ Sage sensor.

This gas producer is also a customer of Sage Metering and challenged us with this problem. The competitor’s ½ inch flow sensor was not durable enough to sustain the harsh conditions of the flare gas system.

A team of Sage Metering engineers set out to develop a heavy-duty sensor probe designed to work in harsh industrial environments such as the client’s flare application. What emerged was a fast responding ¾ inch diameter sensor and probe. The Sage sensors are resistance temperature detectors (RTDs), consisting of extremely durable reference-grade platinum windings housed in a protective 316 SS sheath.
Sage Advice

Sage Prime Thermal Mass Flow Meter

The client installed Sage Prime with the new ¾” sensor at the client’s location. Since the installation, the Sage meter has performed well through several upset events and solved the customer’s problem in high flow and similar adverse conditions. Even under upset conditions, the Sage heavy-duty probe and sensor withstood damage.

Sage meters are factory calibrated and configured for specific applications. They are easy to install directly into the pipe without the need for field set-up and calibration. Sage offers insertion as well as in-line meters, with built-in flow conditioners. These direct mass flow meters are highly accurate and repeatable and have a negligible pressure drop.

The Sage meter has an extraordinary rangeability of 1000 to 1. Because of its low-end sensitivity and wide turndown, the meter accurately measures down to 5 SFPM, making it extremely useful in flare applications. It can measure the low flow in typical venting and high flows associated with upset conditions.  The meter provides  4 – 20 mA and pulsed output with Modbus compliant RS485 RTU communications. The Sage meters feature graphical displays of flow rate, totalized flow, and gas temperature, with continuous diagnostics. For difficult-to-reach pipes or locations with intense radiant heat, a remote style meter offers up to 1000 feet of lead length compensation between the sensor and transmitter.


With the Sage meter installation with the ¾ inch probe and sensor, the client can now measure and monitor flare gas at this facility even under upset conditions, which helps keep their facility safe and comply with environmental regulations.

If you have a challenging flow application and would like some Sage advice, or call us today at (866) 677-7243.

Flare Gas Applications – A Guide for Thermal Mass Flowmeters

One thought on “Measuring in Upset Conditions Just Got Easier

  1. Avatar
    Ernesto M Granados says:

    I have commented with several user about the use of Thermal flow meter and always the main complaint of my customers, is the problem with the wet gas, second complaint with very low pressure or flow.
    When the sensor get wet it doesn’t work appropriately do you have any solution for this problem?

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