Modular magnetostrictive displacement sensor having a waveguide protected by a material with a thermal coefficient of expansion the same as the waveguide

A magnetostrictive displacement sensor comprising:

• a first housing;
• a waveguide formed of magnetostrictive material, said waveguide having first and second ends;
• means for mounting said first end of said waveguide in said first housing with said waveguide extending from said first housing;
• a protective member surrounding said waveguide and formed of material having a thermal coefficient of expansion substantially the same as the thermal coefficient of expansion of said waveguide magnetostrictive material;
• at least one magnet disposed proximate said waveguide;
• means for generating electrical pulses in a direction along said waveguide;
• a printed circuit board removably mounted within said first housing;
• a converter means mounted on said printed circuit board for generating an electrical signal in response to a torsion pulse in said waveguide caused by said at least one magnet and created by the Wiedemann effect, at least one of said waveguide and said at least one magnet moveable with respect to the other;
• means responsive to said electrical signal for indicating the position of the magnet along said waveguide.