New techniques for the non-contact measurement of displacer motion of a miniature split-Stirling cryocooler
Journal
Cryogenics
Journal Volume
36
Journal Issue
8
Pages
573-578
Date Issued
1996
Author(s)
Abstract
This paper proposes optional methods to calibrate the static sensitivity of the measurement of displacer motion inside the cold finger of a split-Stirling cryocooler. The relative displacement measurement method, as previously proposed, required that the regenerator matrix material should have such a high magnetic permeability that the linear variable-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 calibration of static sensitivity: contact, purge or dynamic calibration methods. Temperature compensation is also found to be necessary to transfer the LVDT voltage to the true displacer displacement when performing the non-contact measurement of the displacer motion. © 1996 Elsevier Science Limited.
Type
journal article