GB1330345A - Refrigeration method and apparatus - Google Patents

Abstract

1330345 Refrigerating AIR PRODUCTS & CHEMICALS Inc 15 Oct 1970 [20 Oct 1969] 49160/70 Heading F4H In a device for producing cryogenic refrigeration, high pressure fluid, e.g. helium gas, is supplied through a line 26, valve 28, line 30, regenerator 32, line 34 and heat exchanger 36 to the lower, cold end of a chamber 12 in a housing 10 having a displacer 18 surrounded by a seal 20 to separate the cold end from the upper, warm end of the chamber. A surge volume chamber 14 is formed from the uppermost portion of the housing which is separated from the chamber 12 by the top 24 of the chamber 12 having an orifice 16 therein. A capillary tube 48 is connected between the chamber 14 and conduit 30 to control the pressure in the surge volume chamber to a pressure approximately intermediate the HP and LP in the hot end of of the chamber 12. In use, the HP fluid is passed to the cold end and raises the displacer until the pressures in the hot and cold ends equalize whereafter the surge volume chamber receives gas from the hot end, allowing the displacer to rise and the cold displaced volume to be filled with further HP gas. Closure of the valve 28 occurs when the displacer in the topmost position when an exhaust valve 42 is open and the pressure therefore decreases to expand and cool the gas which reverses flow to exhaust through the valve 42 and a heat exchanger 44 which removes excess heat generated in the gas by forcing through the orifice 16. Ambient air flow over the surge volume chamber is utilized as the means for absorbing sensible heat generated at the hot end of the housing. The process continues until the pressure below the displacer decreases to allow gas flow from the chamber 14 back to the chamber 12 forcing the displacer to the bottom 22 of the housing whereafter the cycle is recommenced. The regenerator may include fine wire screens or metal spheres. In a modification, the regenerator may be positioned within the displacer, Fig. 2, HP fluid being passed thereto through the side of the housing 10, or the displacer may be of stepped configuration within a correspondingly shaped housing as in Fig. 3, or in a further form, Fig. 4, two spaced displacers may be connected by a slack coupling means. In a further embodiment, Fig. 7 an electrically driven motor alternately admits HP gas to the cold end and vents the cooled gas. Supply of refrigeration fluid may be controlled by an automatic timing device.