Co-Axial pulse tube for oxygen liquifaction

Abstract

Industrial Research Ltd (IRL) previously developed a single-stage, inline, pulse tube for use with their metallic-diaphragm pressure wave generator (PWG), achieving 45 W of cooling power at 77 K, with 19.5 % of Carnot efficiency (based on the PV input power). This paper describes the conversion of the inline pulse tube to a co-axial configuration that provides a more accessible cold finger. Sage pulse tube simulation software was used to model the modified pulse tube and predicted 105 W of cooling power at 90 K, with an indicated input power of 1350 W. The pulse tube operated at 50 Hz, with a mean helium working pressure of 2.5 MPa and was closely coupled to a 60 ml swept volume PWG. The experimental results yielded more than 100 W @ 90 K with 2.5 MPa of gas pressure, with a lowest no load temperature of 39.7 K with 1.4 MPa of gas pressure. Details of the development, experimental results and correlations to the Sage model are discussed.

A free-piston Stirling cryocooler using metal diaphragms

“…The displacer movement is timed in such a way that the bulk of the gas is in the warm end for the compression part of the pressure cycle and in the cold end for the expansion part. Instead of using a mechanically driven displacer as seen in Philips-style Stirling cryocoolers [6], the free-piston Stirling system uses differential gas pressure on the ends of the displacer for movement. The warm side of the displacer is divided into two regions: one region (A2) experiences the supplied pressure wave, http://dx.doi.org/10.1016/j.cryogenics.2016.08.005 0011-2275/Ó 2016 Elsevier Ltd. All rights reserved.…”

“…Diaphragm pressure wave generators (DPWG) developed by Industrial Research Ltd, now called Callaghan Innovation [1][2][3][4], have matured over the last decade to become a useful alternative to linear motor pressure wave generators for Stirling and pulse tube cryocoolers [5][6][7][8]. To date, 15 metal diaphragm pressure wave generators have been made and operated with swept volumes from 20 cc to 1000 cc and with 500 W to 30 kW input power, respectively.…”

High efficiency, low frequency linear compressor proposed for Gifford-McMahon and pulse tube cryocoolers

“…Linear compressors connected directly to the cold head are a potential candidate to improve this waste energy situation. Caughley et al 2 have shown efficient systems using a high frequency metal diaphragm compressor. This paper describes our work on low frequency linear compressors.…”

Commercialisation of Pulse Tube cryocoolers to produce 330 W and 1000 W at 77 K for liquefaction

“…To date, 15 pressure wave generators have been made with swept volumes from 20 cc to 1000 cc [1]- [3]. These have all been coupled to pulse tube [4]- [7] or Stirling [8], [9] cold heads. Two of the DPWGs have each achieved over 7000 hours of operation.…”