1. Field of the invention
This invention relates to natural draught cooling tower assemblies in which the fluid to be cooled flows through finned tubes associated with a tower and air is assisted to flow over the tubes by chimney draught produced by the tower. The fluid to be cooled may change its state, i.e. be condensed, or may be cooled without change of state. Such assemblies find application in condensing steam and/or cooling condensate from steam turbines.
2. Description of the Prior Art
More specifically the invention is concerned with a natural draught cooling tower assembly of the kind, hereinafter referred to as of the kind specified, comprising a tower having a chimney part and apertured support means between the lower end of the chimney part and the ground, a heat-exchanger assembly within the lower part of the tower and spaced above the ground, the heat exchanger assembly comprising a plurality of finned tubes, the tubes being grouped together in banks, each bank comprising a plurality of parallel tubes arranged side by side, the banks being arranged in side by side pairs so that each pair forms a V-frame or A-frame with the banks diverging upwardly or downwardly from the apex of the V or A and with the tubes of each bank having their longitudinal axes running parallel to the apex of the frame, the frames covering a major part of the plan area of the lower part of the tower, and the support means and the heat exchanger assembly being arranged so that air can pass through the support means and through the heat exchanger assembly from beneath the assembly into the tower.
Heretofore in cooling tower assemblies of the kind specified the frames have been arranged so that, although the major part of said plan area has been occupied by the frames, there have been significant parts of the area not so occupied.
In one arrangement of the A-frames these have been arranged with their apices extending radially from the centre of the plan area which has been circular. Since the A-frames are rectangular in plan it will be appreciated that there will be unoccupied sector-shaped spaces between adjacent A-frames. These spaces have to be sealed to prevent air escaping past the tubes rather than flowing over them.
In another arrangement of A-frames which have all been of the same length, the apices of the frames have been arranged to lie in two sets of parallel planes, the planes of the two sets being mutually perpendicular. Since the A-frames are all the same size and are rectangular in plan this has meant that the heat exchanger assembly has had a plan area of cruciform shape and has been bounded by two sets of mutually perpendicular lines, each set consisting of four lines, so that there have been significant sector-shaped spaces left between the outer periphery of the plan area of a heat exchanger assembly, between the junctions of the arms of the cruciform shape and the periphery of the plan area of the lower part of the tower, these spaces not being occupied with heat exchanger surface.
It is an object of the present invention to provide a cooling tower assembly of the kind specified in which greater utilization is made than heretofore of the plan area of the lower part of the tower.