US Patent 7437940 Apparatus for measuring differential pressure

An apparatus for measuring differential pressure includes first and second sensor units. The first sensor unit detects directly a first pressure of a substance at a first position and acquires a first detection result that indicates the first pressure. The second sensor unit detects directly a second pressure of the substance at a second position different from the first position. The second sensor unit acquires a second detection result that indicates the second pressure and receives the first detection result from the first sensor unit. The second sensor unit calculates a differential pressure between the first and second positions with reference to the first and second detection results.