In a propane regulator, which pressure is the closing force?

In a propane regulator, which pressure is the closing force?

• A. Manifold pressure
• B. Downstream pressure
• C. Midstream pressure
• D. Upstream pressure

Answer: (D)

In a propane regulator, the force that tends to close the valve comes from the upstream gas pressure. The diaphragm and valve stem are arranged so that the pressure on the upstream side pushes the diaphragm toward the valve seat, which closes the flow path. The downstream pressure acts on the opposite side of the diaphragm to push the valve open, and the spring provides additional bias. The regulator maintains a steady downstream pressure by balancing these forces: when downstream demand changes, the opening force from downstream pressure (and spring) adjusts against the closing force from upstream pressure to reach and hold the setpoint. So the upstream pressure is the closing force because it pushes the valve toward sealing.

In a propane regulator, the force that tends to close the valve comes from the upstream gas pressure. The diaphragm and valve stem are arranged so that the pressure on the upstream side pushes the diaphragm toward the valve seat, which closes the flow path. The downstream pressure acts on the opposite side of the diaphragm to push the valve open, and the spring provides additional bias. The regulator maintains a steady downstream pressure by balancing these forces: when downstream demand changes, the opening force from downstream pressure (and spring) adjusts against the closing force from upstream pressure to reach and hold the setpoint. So the upstream pressure is the closing force because it pushes the valve toward sealing.