Process and apparatus for refrigeration by work-producing expansion

Claim 1

IN A PROCESS OF REFRIGERATING BY THE WORK PERFORMING EXPANSION OF A COMPRESSED GAS, THE METHOD OF HEATING THE COMPRESSED GAS IN AN ARRANGEMENT OF AT LEAST THREE CYCLICALLY ALTERNATED REGENERATORS HAVING HEAT STORING MASSES BEFORE THE WORK PERFORMING EXPANSION OF THE GAS, WHICH COMPRISES: IN A FIRST PERIOD LEADING A GAS THROUGH A REGENERATOR OF SAID ARRANGEMENT FROM THE WARM TO THE COLD END THEREOF TO COOL THE GAS AND CONDENSE CONTAMINANTS, IN A SECOND PERIOD LEADING A SCAVENGING GAS THROUGH SAID REGENERATOR FROM THE COLD TO THE WARM END THEREOF TO REMOVE A SUBSTANTIAL PART OF THE CONDENSED CONTAMINANTS FROM THE HEAT STORING MASS THEREOF AND IN A THIRD PERIOD WARMING THE GAS TO BE EXPANDED AND REMOVING THE REMAINING CONDENSED CONTAMINANTS FROM SAID HEAT STORING MASS BY TRANSFERRING TO SAID GAS AT LEAST A PART OF THE HEAT STORED IN THE HEAT STORING MASS OF SAID REGENERATOR BY PASSING SAID GAS IN DIRECT CONTACT WITH SAID HEAT STORING MASS.