Sereg, S.a.

Elsag International N.v.

Sereg

Pierre C Bertrand

Joseph C Nemer

Tourang Birangi

Thijlbert C De Paepe

A method for compensating for the differences in temperature across a cell used to sense pressure. A microprocessor calculates a dynamic temperature factor signal by multiplying a signal representative of temperature change across the cell by a coefficient based on measurements made of the effect of temperature change on the cell. The dynamic temperature factor signal is then subtracted from the signal representative of the differential pressure sensed by the cell to thereby provide the dynamic temperature compensation.

Dynamic temperature compensation for a pressure cell

The diaphragm comprises a peripheral zone (12) and a central zone (16) in the same plane. Between these zones there is a corrugated zone comprising 2n corrugated portions (18.sub.1 to 18.sub.4) which are separated by connection zones (20.sub.1 to 20.sub.4). Any one corrugated portion may be derived from the adjacent corrugated portion by a rotation through 180.degree. about the connection zone, or else by a rotation of 2.pi./2n about the diaphragm axis followed by a symmetry about the housing plane.

Corrugated diaphragm for a pressure sensor

In order to reduce the measurement time of a device for measuring fluid temperature, in particular of water in the primary circuit of a nuclear power station, the device comprises a resistance probe (50) sensitive to the temperature of a stem (23) which is removably slid into a socket (1) itself secured in the pipe in which flows the fluid (10) whose temperature is to be measured. The stem ends with a surface in the form of a convex segment of a sphere (39) arranged to be urged by a resilient member onto a dish (42) force-fitted in the bottom of the socket.

Device for measuring temperature

A measuring diaphragm (1) separates in a pressure-tight manner two half chambers (9, 10) suitable for being respectively subjected to two pressures to be compared. In a central zone of the diaphragm (1) there are two magnetic cores (118, 127) which are disposed on opposite sides of the diaphragm in respective ones of the half chambers and which are displaced with the diaphragm when the faces of the diaphragm are subjected to different pressures. The cores are movable inside respective simple inductors (132, 133 ), thereby varying their impedances. By measuring this impedance variation it is possible to determine the position of the cores in the associated inductors, and consequently to establish the difference between the pressures being applied to respective faces of the measuring diaphragm (1). The above arrangement provides for automatic zero correction in an inductive differential pressure sensor.

Inductive differential pressure sensor

The measuring apparatus comprises a sensor (11) having a first electrical characteristic (balance of inductance) which is directly modifiable by the magnitude of a quantity or characteristic to be measured (e.g. pressure). A remote electrical power supply (27) excites the sensor over first and second conductors (28, 29) of an electrical link (22) having a second electrical characteristic (e.g. resistance) which is capable of disturbing the measurement. A third conductor (21) in the link is connected to a measuring instrument (24). In order to avoid measurement errors due to leakage currents in the link, the power supply (27) continuously monitors the electrical characteristics of the link and regulates its excitation output as function thereof and in such a manner as to tend to eliminate disturbing effects on the measurement.

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Igny, France

Pierre C Bertrand