초록 ▼

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 a

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).

대표청구항 ▼

1. 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 condensat

1. 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. 2. A method according to claim 1, wherein the condensor has a plurality of heat exchanger modules and a separate fan means and shutter elements for each module, and including the step of regulating the flow of air in response to falling condensation pressure, by decreasing the flow of the fans from a highest value toward a first lower value simultaneously for all modules and in response to the temperature of the condensate in any of the modules falling under a prescribed value reducing the flow of air to that module down to the aforementioned first lower value. 3. A method according to claim 2, wherein, in response to the condensation pressure and/or condensate temperature remaining below said prescribed value after diminishing the flow to the first lower value, the regulating step includes diminishing the intake of atmospheric air by increasing the length of the curtain provided by said shutters. 4. A method according to claims 1, 2, or 4 including the steps in response to the outdoor temperature falling under a prescribed value, of increasing the length of said curtain to screen the entire flow area of said heat exchangers, and to divert all of the heated air emerging from the heat exchangers into the inlet of the fan means to impinge on and be united with cold air sucked in by the fan means, and upon increase of the condensation pressure, of first increasing the flow of the fan means to the highest value, and thereafter reducing the length of the curtain; then upon lowering of the condensation pressure first reducing the flow of the fan means to a second lower value, and thereafter increasing the length of the curtain toward maximum screening by the shutter elements. 5. A method according to claim 1 wherein the condensor has a plurality of modules and a separate fan means and shutter elements for each module, and including the step of regulating in each module both the shutters and the blade angle of the fan manually both in synchronous operation and individually. 6. 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. 7. An apparatus according to claim 6, wherein the steam condensor comprises a plurality of modules each containing an adjustable fan and at least one heat exchanger with coils for steam condensation, said steam line being above said heat exchanger, said shutters being arranged to form said channel to extend across the flow area of said heat exchanger obliquely down-ward and out-ward from the steam line, the inlet of the fan being located below said heat exchanger and positioned to withdraw air from below said heat exchanger and to press it up through the heat exchanger. 8. An apparatus according to claim 6 or 7, including means to adjust the shutters to control the length of the recirculation channel extending from said one side across the flow area, and means to adjust the flow of the fans. 9. An apparatus according to claim 8 including a pressure sensor for the steam condensation pressure and a condensate temperature sensor, and an outdoor temperature sensor and connections from said sensing means to said adjusting means to change the flow of the fans and the length of the shutter curtain and thereby control the recirculation of warmed up air from the fans through the heat exchangers in response to changes in said pressure and temperatures. 10. 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. 11. An apparatus according to claim 7 wherein said fan is an axial fan having blades and means to adjust the blade angle both in steps and continuously.