Embodiments for protecting low-pressure blood pressure sensors in high-pressure fluid flow applications by equalizing pressure on both sides of a pressure sensor's diaphragm during high pressure are disclosed. A sensor protection device may include a pressure sensor assembly, a housing, and a plunger assembly. During low pressure, fluid in the primary flow path can flow through the housing, transferring its pressure to a first side of the diaphragm； the plunger assembly can prevent fluid flow into a secondary flow path in the housing, transferring atmospheric pressure to a second side of the diaphragm. During high pressure, fluid can still flow through the primary flow path, and the plunger assembly may now allow fluid flow into the secondary flow path, transferring pressure from the same fluid to the second side of the diaphragm to equal pressure across the diaphragm. The plunger assembly may automatically transition between low- and high-pressure configurations.
