IT968601

1390549 Venting heat exchangers TRANSELEKTRO MAGYAR VILLAMOSSAGI KULKERESKEDELMI VALLALAT 3 Oct 1972 [5 Oct 1972] 45593/71 Heading B8X [Also in Division F4] In a heat exchanger for cooling water utilizing a natural or forced flow of air across a plurality of parallel tubes extending between header chambers, a venting device, in the form of an upright vent pipe 2 surrounded by a jacket 4 defining therewith a chamber 5 which is filled with an antifreeze liquid, e.g. oil, communicates with the top of the upper header 1. The venting device permits air to enter the exchanger during emptying operations and permits air to be expelled from the exchanger during normal operation and during initial filling of the exchanger with water. The antifreeze liquid, which is heated by heat exchange with warm water passing through the exchanger and/or by an electric resistance heater 8, serves to prevent freezing of water in the vent pipe 2 at low temperatures. The jacket 4 is surrounded by heat insulation 6. A single venting device may be used in conjunction with a plurality of heat exchangers (see Figs. 3, 3a). In a modified embodiment (see Fig. 4, not shown), the vent pipe includes a portion (3) of reduced cross-section, and a sphere (4) is provided to float on the surface of the water in the pipe to minimize absorbtion of ambient air into the water during normal operations. The sphere can move between upper and lower grids (8 and 9) disposed in pipe portions of unreduced diameter. In another embodiment (see Figs. 5, 5a) a plurality of small spheres forming a layer on the water surface in the vent pipe is used instead of a single sphere.