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AssigneeFlakt Aktiebolag
InventorsPer-Olof Jakobsson, Sven Beverskog
Estimating the term…
Method and apparatus for improving the operation of forced-air-cooled steam condensors having a bank of air-cooled heat exchangers connected between steam lines and condensate conduits. Air is forced through the heat exchangers by fans and shutters are provided to either discharge the spent air to atmosphere or to recirculate the spent air into the fan inlets to mix with fresh outside air. The steam pressure in the steam line is sensed along with the temperatures of the condensate in each exchanger and of outside air. The condensate conduits are in the recirculation path of spent air, and the fan is adjustable to control the quantity of air forced through the exchangers. By controlling the shutters and the fans in response to the pressure and temperatures, a highly-efficient cooling effect is achieved. According to the invention there are provided sensor-governed motor-driven roll-shutters (11), which more or less can screen the heat exchangers (12) and thereby create a recirculation channel (17) for the warmed up air, and there are furthermore provided sensor-governed adjustments of the blade angles of fans (13). The condensor (2) has an upper steam pipe-line (9) and connected thereto the heat exchangers (12), which preferably are arranged trapezoid-like in two parts covering the lower fans (13), one for each so called module, whereby a roll-shutter (11) is arranged outside of and at distance from each heat exchanger part, and whereby the roll-shutters are rolled up close to the steam pipe-line (9).
A method of regulating cooling of an outdoors-air-cooled steam condensor having heat exchangers with an air flow area and fan means to blow air outwardly through the entire air flow area of the heat exchangers, said condensor being fed by steam-line and being connected to discharge into condensate conduits, the improvement comprising the steps of providing screening and diversion shutter elements forming a curtain transverse to the direction of air flow through the air flow area of and spaced from the heat exchangers at a distance on the outside for diverting the outward flow and providing an air recirculation channel starting from the vicinity of said steam-line and extending along the outside of said heat exchangers towards said condensate conduits, and using said curtain to divert the outward flow to follow said channel and flow toward said conduits without substantially diminishing the flow through the heat exchanger, sensing the condensation pressure of the steam, the condensate temperature, and the outdoor air temperature, positioning the inlet of the fan means downstream of said conduits in the direction of the recirculation flow so that the flow from said channel passes said conduits and is recirculated into said fan, and regulating both the length of the curtain and the blowing of said fan means to keep the condensation pressure at a substantially constant value and the condensate temperature above freezing, the length of the curtain controlling the amount of the recirculated air, and the fan controlling the total quantity of air passing through the heat exchangers.
An apparatus for improving the operation of an outdoor-air-cooled steam condensor with heat exchangers arranged on a support, said exchangers having an air flow area and fan means for blowing air outwardly through said air flow area, said exchangers being fed by a steam-line at one side of said flow area and leading into condensate conduits at the other side of said flow area, control means for reducing the risk of freezing comprising screening and diversion means consisting of motor-driven roll-type shutters forming a curtain transverse to the direction of air flow through said air flow area and spaced from the heat exchangers to form at the outer side an air recirculation channel starting from the vicinity of the steam-line at said one side and diverting warmed-up air currents towards said condensate conduits at said other side, and means to adjust the extension of said shutters both in steps and continuously, the intake of said fan means being downstream of said conduits in the direction of recirculation flow so that warmed-up air currents are recirculated through the fan means after being passed over said conduits.
An apparatus according to claim 10 wherein said steam-line is supplied by a turbine and said pressure sensor is at the outlet of said turbine.
Dependencies are inferred from the claim text.