A sensor element includes a sensor chip and a diaphragm base joined to a surface of the sensor chip. The sensor chip includes a first diaphragm for measuring differential pressure between a first pressure and a second pressure and a second diaphragm for measuring absolute pressure or gage pressure of the second pressure. The diaphragm base includes a third diaphragm to directly receive a fluid that is a measurement target and has the first pressure, and a fourth diaphragm to directly receive a fluid that is a measurement target and having the second pressure. The sensor element has a liquid amount adjustment chamber to make an amount of a first pressure transmission medium filled in a first pressure introduction path and an amount of a second pressure transmission medium filled in a second pressure introduction path to be equal to each other.

The invention relates to a pressure sensor (10) comprising a cavity (12) containing a liquid, said cavity (12) being closed at a first end by a first diaphragm (20a) and at a second end by a second diaphragm (20b), and a measuring body (30) which comprises a strain gauge (31) positioned inside said cavity (12), characterized in that the measuring body (30) is mechanically connected only to one diaphragm among the first diaphragm (20a) and the second diaphragm (20b) by a connection member (50), the measuring body (30) comprising a shape having central symmetry and the connection member (50) being fastened to the center of symmetry of said measuring body (30).

A corrosion protection element is described, with which in simple and cost effective manner a reliable corrosion protection of field devices can be provided, which field devices comprise at least one component of stainless steel in contact with an environment of the field device. Corrosion protection elements of the invention are distinguished by features including that they are embodied as sacrificial anodes comprising iron or rustable steel and have a form, which is embodied in such a manner that they can be applied to the component of the field device in such a manner that the sacrificial anode is in electrically conducting contact with the component.

A sensor chip of a sensor element includes a diaphragm for measuring a differential pressure between a first pressure and a second pressure, a diaphragm for measuring an absolute pressure or a gauge pressure of the second pressure, a first pressure introduction path that transmits the first pressure to the diaphragm for measuring a differential pressure, and a second pressure introduction path that transmits the second pressure to the diaphragms. When the transmission of the first pressure or the second pressure to the diaphragms is indicated by an equivalent circuit, a path for transmitting the first pressure and a path for transmitting the second pressure are symmetrically formed.

In an electrostatic capacity sensor 1, first electrodes 11a to 11d are provided on a substrate 10, and an electrode support 14 has dielectric properties and elasticity and is fixed to the substrate 10. A second electrode 12 is provided in the electrode support 14 so as to face the first electrodes 11a to 11d with a distance from the first electrodes 11a to 11d. The electrostatic capacity sensor has improved durability.

A diaphragm pressure gauge includes: a structure disposed under pressure to be measured; two diaphragms attached to the structure so as to oppose each other; and a detection element that is fixed to the two diaphragms to detect displacements of the two diaphragms. In each of the two diaphragms, when one of two surfaces is designated an opposing surface and the other surface is designated a non-opposing surface, the structure and the two diaphragms set a space faced by one of the opposing surface and the non-opposing surface as an airtight space to be kept in a reference vacuum, and the other of the opposing surface and the non-opposing surface is subjected to the pressure to be measured.

According to an example aspect of the present invention, there is provided a MEMS pressure sensor, comprising: a sensor portion comprising a deformable membrane and a first volume, and a valve portion comprising a first output to a first side of the pressure sensor and a second output to a second side of the pressure sensor. The valve portion is operable to close the second output and open the first output to equalize pressure in the first volume with pressure at the first side of the pressure sensor for calibrating the sensor; and close the first output and open the second output to equalize pressure in the first volume with pressure at the second side of the pressure sensor for pressure measurement.

A pressure measuring cell or flow rate measuring cell includes a pipe piece in which either a membrane to which a pressure that is to be measured is applied or an orifice plate is arranged in the cross-section through which a fluid flows, wherein the membrane or orifice plate and the pipe piece are formed together and interconnected via a solid-body joint, where a sensor is arranged outside the pipe piece near the solid-body joint or is accessible from this side, a tubular carrier part diverts forces past the solid-body joint when the pressure or flow rate measurement cell is being installed, and where the tubular carrier part has an inner diameter that is greater than the outer diameter of the pipe piece and has a wall in its cross section with a central circular opening, into which the pipe piece shortened to the thickness of the wall is inserted.

A differential MEMS pressure sensor includes a topping wafer with a top side and a bottom side, a diaphragm wafer having a top side connected to the bottom side of the topping wafer and a bottom side, and a backing wafer having a top side connected to the bottom side of the diaphragm wafer and a bottom side. The topping wafer includes a first cavity formed in the bottom side of the topping wafer. The diaphragm wafer includes a diaphragm, a second cavity formed in the bottom side of the diaphragm wafer underneath the diaphragm, an outer portion surrounding the diaphragm, and a trench formed in the top side of the diaphragm wafer and positioned in the outer portion surrounding the diaphragm.

A pressure sensing package includes a sensor chamber and an annular chamber extending about the sensor chamber. A primary diaphragm divides the sensor chamber into a first part receiving a first pressure and a second part including a differential pressure sensor approximately centered with respect to a sensor axis and a first transmission fluid. The first transmission fluid transmits the first pressure to a first differential pressure sensor face. A secondary diaphragm divides the annular chamber into a first part receiving a second pressure and a second part including a second transmission fluid. The second pressure is transmitted to a second pressure sensor face via the secondary diaphragm and the second transmission fluid. The primary and secondary diaphragms are positioned with respect to one another along the sensor axis direction such that pressures other than the first and second pressures acting on the pressure sensor sum to approximately zero.