G2 Gas Fitter Exam 2025 – 400 Free Practice Questions to Pass the Exam

The component that determines the direction of the gas stream down the center of a venturi in an atmospheric burner is the venturi tube itself. The venturi tube is designed with a specific shape that narrows at the center, causing an increase in gas velocity and a corresponding decrease in pressure as the gas flows through it. This principle of fluid dynamics, known as the Venturi effect, ensures that gas is efficiently drawn into the combustion zone when mixed with air.

As gas enters the venturi, the design naturally directs the flow towards the center, maintaining a consistent and controlled gas stream necessary for proper combustion. This directional flow is essential for achieving optimal performance in an atmospheric burner, where a precise mixture of gas and air is critical for efficient burning and to minimize emissions.

Other components, while involved in the overall gas system, do not determine the direction of the gas stream specifically within the venturi. For instance, gas flow meters measure the flow rate of gas, pressure regulators maintain a constant pressure regardless of the flow, and air shutters adjust the mix of air and gas; however, none of these components inherently direct the gas stream in the same way that the geometry of the venturi tube does.