Patent ID: 7205685

Claim:
A solenoid plunger system for an electropneumatic pressure transducer, comprising at least partly a solenoid plunger and a core in a casing which focuses magnetic field lines M, wherein the solenoid plunger includes at least a first recess on a side facing toward the core and/or the core includes at least a first recess on a side facing toward the solenoid plunger, wherein an air gap is provided between the solenoid plunger and the core, the air gap being adjustable by relative movement between the solenoid plunger and the core, during which relative movement the solenoid plunger can, at least partly, be moved into or out of the first recess in the core and/or the core can be moved, at least partly, into or out of the first recess in the solenoid plunger; wherein the casing includes at least a first shell and a yoke, each of high magnetic permeability, wherein the first shell is arranged between the solenoid plunger and at least one coil and/or at least one magnet, and the air gap is arranged in a region between the first shell and the yoke; and wherein the casing includes a second shell of high magnetic permeability between the first shell and the yoke, said second shell comprising at least one recess on its side facing away from the core for focusing magnetic field lines M from the yoke onto the core, and in the region of the recess of said second shell, the yoke, the core and/or an adjustment member of high magnetic permeability is/are moveable relative to said second shell for adjusting the effective magnetic length L of the recess of the second shell.