What pressure is affected by turning the screw on an adjustable regulator?

Adjustable regulators are designed to control the pressure of gas in a system, and their primary function is to manage the outlet pressure, which is the pressure of the gas that is delivered downstream to the appliance or system using it. When you turn the screw on an adjustable regulator, you are effectively changing the resistance and controlling the flow of gas, which in turn adjusts the outlet pressure.

Adjusting the screw increases or decreases the force on a diaphragm inside the regulator, which allows for fine-tuning of the pressure being supplied. This capability is essential for ensuring safety and optimal operation of appliances that rely on specific gas pressures for efficient performance.

In contrast, inlet pressure refers to the pressure entering the regulator from the gas supply source and does not directly change with adjustments made to the regulator itself. Static pressure is a measure of pressure at rest and is generally constant in a closed system. Atmospheric pressure is the pressure exerted by the weight of the atmosphere around us and is not influenced by gas regulation systems in this context. Overall, the correct answer reflects the primary function of an adjustable regulator in manipulating the gas pressure delivered to appliances.