Yp. Yang et al., NEW TECHNIQUES FOR THE NONCONTACT MEASUREMENT OF DISPLACER MOTION OF A MINIATURE SPLIT-STIRLING CRYOCOOLER, Cryogenics, 36(8), 1996, pp. 573-578
This paper proposes optional methods to calibrate the static sensitivi
ty of the measurement of displacer motion inside the cold finger of a
split-Stirling cryocooler. The relative displacement measurement metho
d, as previously proposed, required that the regenerator matrix materi
al should have such a high magnetic permeability that the linear varia
ble-differential transformer (LVDT) could measure the displacer motion
without large signal amplification. This would be impossible for low-
permeability materials, e.g. stainless steel 316L and 304L, contained
in the displacer. Therefore, three options are proposed for the calibr
ation of static sensitivity: contact, purge or dynamic calibration met
hods. Temperature compensation is also found to be necessary to transf
er the LVDT voltage to the true displacer displacement when performing
the non-contact measurement of the displacer motion. (C) 1996 Elsevie
r Science Limited