Hottinger Baldwin Measurements Inc.

Reimar Hellwig

Ralf Waegner

A precision pressure sensor in the form of a load cell has a mounting ring closed at one end by an end wall which has axially outwardly facing dead-end holes therein to form sensor beams each having an axially outwardly facing plane surface to which strain gages are bonded. The dead-end holes have bottoms forming sensor membranes. Opposite the closed end the mounting ring encloses a cavity forming a sensor space which is closed by a closure plug that simultaneously has a bore for admitting fluid under pressure to be measured into the sensor space. A ring groove in the end wall has approximately radially sloping surfaces which together with the dead-end holes determine the minimum cross-section of the measuring beams. The ring groove also determines the minimum thickness of the sensor membranes.

Pressure sensor and method for calibrating pressure sensors

The deforming body of a force measuring device or load cell is provided with radial stems (3) equipped with foil strain gages (7) and integrally connected to a hollow cylindrical outer ring (1) and to a central hub (2). The outer ring (1) and the central hub (2) extend axially on both sides of a central plane (5) at least as far as three times the largest thickness of the radial stems (3). A force introducing flange (13) is arranged on the outside of the outer ring (1) and lies in the radial central plane (5) of the radial stems (3). Each stem (3) is thicker at its ends near the hub and ring so that the thinnest stem portion is located approximately intermediate the stem ends for providing a linear characteristic for the load cell which is substantially non-sensitive to any loads other than loads applied perpendicularly to the central radial plane.

Growing community of inventors

Ober-Ramstadt, Germany

Reimar Hellwig