A sensor device, at least for measuring a fluid pressure, has a base body and has a fibre-optic sensor unit which includes at least one sensor element which is in the form of a light-conducting fibre and which extends along a longitudinal extension of the base body at least substantially helically around the base body, wherein a transmission unit, which is arranged in at least one measuring range around the base body and the at least one sensor element, is configured to receive a fluid from an environment and to transmit a fluid pressure to the sensor unit for a deformation of the at least one sensor element.

An apparatus for measuring pressure of fluid in a shunt includes a distensible member arranged adjacent to a graduated scale. The shunt includes a shunt valve and the apparatus is attachable to, or incorporated into the shunt at a location either at the shunt valve or upstream of the shunt valve. Both the distensible member and the scale include radiopaque markers. The fluid in the shunt acts directly on the distensible member and the distensible member is distensible in the direction of the scale.

A sensor device, at least for measuring a fluid pressure, has a base body and has a fibre optic sensor unit which includes one or more sensor elements(s) which is in the form of a light conducting fibre and which extends along a longitudinal extension of the base body at least substantially helically around the base body. A transmission unit, which is arranged in at least one measuring range around the base body and the one or more sensor elements(s), receives a fluid from an environment and transmits a fluid pressure to the sensor unit for a deformation of the at least one sensor element.

A measuring system, for a physical variable, includes a housing, a measuring tube having at least one tubular deformation body having a cross-section which is deformed at least partially and which is configured to expand elastically under pressure, two feed sections attached to end sections of the deformation body, two sealing sections for sealingly coupling the measuring system to a process, and two molded support sections to carry the housing. A measuring sensor system measures values of at least one of a stretching or a widening at at least two points on a section of the deformation body. An evaluation unit evaluates measured values of the stretching and widening and outputs them as a measurement signal. The housing at least partially surrounds and stabilizes the measuring tube on an outside and is provided with a vacuum and/or a negative pressure compared to the outside atmosphere.