Consists of a diaphragm of magnetic material disposed between two fixed coils, resulting in a rugged assembly with good environmental characteristics and reliability
Celsum Technologies now offers the NE74 series miniature differential pressure sensors.
These are available with pressure ranges from +/-150 millibars through to +/-100 bar, have a ten-times full-scale over-range capability, and will operate at line pressures up to 400 bar in differential mode.
They can be supplied in both true differential and absolute versions, and calibrated in bars or psi.
The standard version is manifold mounting, with a wide range of optional threaded connectors.
The NE74 pressure sensor uses variable reluctance technology and consists in essence of a diaphragm of magnetic material that is centrally disposed between two fixed coils, the coils being potted in a high temperature resin and sealed via a welded stainless steel shim.
This completely isolates the coil from the pressure medium.
The diaphragm is machined from a solid, forged section and electron-beam welded to the end pieces.
This construction results in an extremely rugged assembly with superb environmental characteristics and excellent reliability figures (100,000 hours MTBF), claims Celsum.
On application of a differential pressure, the diaphragm is deflected, resulting in an increase in the inductance of one coil and a corresponding decrease in the other.
This is detected by simple external AC conditioning electronics.
NE74 transducers weigh only 100 grammes, are virtually insensitive to shock and vibration, and employ an all-welded 17-4PH stainless steel construction.
Richard Carter, Celsum Technologies's marketing manager, commented: "The NE74 series differential pressure sensors were developed originally for down-hole applications in the oil and gas exploration industries, but their small size, ruggedness, reliability and wide range of full-scale sensitivities makes them ideal for a plethora of tasks in research and development and in OEM machines".
Typical applications include differential pressure measurement in down-hole installations and depth measurement in high temperature and high vibration environments.
