Thermocouples are an instrumental part of safe and efficient operation of gas fire pits, but what are they? How do they work? And what makes them so important? For this edition of our Gas Fire Pit Safety series, we talked to one of our burner engineers to help us take a deep dive into all these questions and more!
What is a Thermocouple?
According to temperature.com, a thermocouple, also known as a "thermoelectrical thermometer", is an electrical device consisting of two dissimilar electrical conductors forming an electrical junction. A thermocouple produces a temperature-dependent voltage as a result of the Seebeck effect, and this voltage can be interpreted to measure temperature.
In simpler terms, it's a temperature sensor.
Pictured: The Outdoor GreatRoom Company Manual Ignition and Thermocouple Assembly
Thermocouples are not unique to gas fire pits, but rather a crucial component to many different items and products you see everyday including diesel engines, thermometers, gas turbines and other devices where temperature plays a important role in operation.
Why is a Thermocouple Important to a Gas Fire Pit?
When it comes to The Outdoor GreatRoom Company's Crystal Fire Plus burners, thermocouples play a huge role in the safety of their operation as our engineer Connor Burmeister explains:
"Since our products are all listed to ANSI Z21.97-2017, they are subject to the performance criteria set forth by that standard."
Part of testing the burners and making sure they meet ANSI standards include how the burner responds to rain, which requires one of two conditions to be met: the burner continues to operate normally or the burner shuts down safely. Connor runs those tests right here in our Engineering Lab to make sure the burners keep going or shutdown safely. Connor explains the dangers if one of those two things don't happen:
"When the rain is applied to the burner, a large steam cloud results and that steam cloud starves the area for oxygen. This results in the flame extinguishing. This situation is akin to a sudden downpour occurring while a burner is in operation."
To make sure this doesn't happen with our burners, our thermocouples sense the absence of the flame and heat and shut off the flow of gas, which prevents a potentially dangerous build up of raw fuel that could cause a fire. Other tests we run include wind, nuisance shutdowns and more!
What Makes OGC's thermocouple different from others in the outdoor fire industry?
As we discussed before, thermocouples are present in many different devices including a variety of gas fire pits across our industry. We recently redesigned our burner and thermocouple to enhance not only overall performance, but also safety, setting the new standard for outdoor gas burners. Connor explains our changes and why we're doing things a bit differently:
"The thermocouple itself is a standard, quick response thermocouple, meaning that it responds quickly to the presence or absence of a flame, or any change in flame behavior. Our thermocouple housing and operation is different than others because we are sensing the main burner flame and do not employ a pilot system."
While pilot systems can be effective, we've found there are scenarios where pilot systems can send signals to the thermocouple that everything is good, when in fact the burner itself isn't even lit up.
"In some instances where a pilot is employed, the entire main burner can be extinguished and sending unburnt fuel while the protected pilot flame continues to burn and give the thermocouple heat, allowing fuel to continue to flow in a potentially unsafe manner," Connor says.
To combat this, our redesign has our thermocouple sense the main burner flame as opposed to a pilot.
"This system was designed by us specifically to operate with our burner and purpose-built by an industry leading ignition component manufacturer. It allows our system to truly be a 'safety ignition system.' With our system sensing the main burner flame, ignition occurs quickly and operation is more accurately and safely monitored."
For more information on gas fire pit safety and other helpful information, check out these blogs:
Clearances to Combustibles & Glass Guards
UL/ULC Listings & Their Importance
"Can I Roast Marshmallows?" and 4 More Common Questions About Gas Fire Pits
Everything You Need to Know About Fire Media for Gas Fire Pits
