Perfectionnement aux échangeurs de chaleur applicable notamment au refroidissement des piles atomiques

846,950. Nuclear reactors. SOC. NATIONALE D'ETUDE ET DE CONSTRUCTION DE MOTEURS D'AVIATION. Nov. 4, 1957 [Nov. 15, 1956], No. 34312/57. Class 39(4). [Also in Group XIII] Fluid flowing through a bundle of tubes or through tube groups in a nuclear reactor, is caused to flow with a pulsating motion tuned to the natural frequency of the tubes, the pulsating flow through an individual tube or tube group being such that it is out of phase with the flow through other tubes or tube groups. The pulsating flows through the tubes or tube groups may be initiated by valves or by either a reciprocating or centrifugal type compresser. Fig. 2 shows one form in which cam operated valves 8, 9 provide the pulsating flow in individual tubes 12, 13 of fluid from a header 6 supplied with a substantially uniform flow of fluid through a duct 5. Embodiments using flap and disc type valves are described. In a further form, Fig. 9, in which the spaces between tubes 30 are filled by the substance undergoing nuclear reaction and which is to be cooled, aerodynamic non-return valves 32 may be provided for each tube or group of tubes in the bundle, and these, in conjunction with a close spacing of the tubes, are said to produce the required fluid pulsations.