The present invention relates to a condenser for condensing exhaust steam of steam turbines of thermal power plants and atomic power plants.
Generally in a steam turbine plant, steam which has worked in a steam turbine and inflated is condensed by a surface contact type-condenser for recovery.
FIG. 11 is a sectional view of one example of the above-described condenser. In a condenser body 1 into which exhaust discharged from the steam turbine not shown there are disposed cooling pipe bundles 2 of a number of cooling pipes which are extended in a first direction (which is perpendicular to the sheet of FIG. 11) and in parallelism with each other, whereby the exhaust from the steam turbine is heat-exchanged with cooling water, such as sea water, river water or others, on the surfaces of the respective cooling pipes and condensed to be drained.
Each cooling pipe bundle 2 is divided in a plurality of pipe groups 2a, 2b, 2c, 2d, 2e, and the pipe groups are defined by partition plates 3, 4 so that the heat conducting pipe groups do not affect by the drain the heat-exchange of the other heat conducting pipe groups. Air cooling pipe groups for condensing residual energy of the steam 6, 7 are provided below the cooling pipe bundle 2. Partition plates 5a, 5b are provided between the cooling pipe bundle 2 and the pipe groups 6, 7 respectively. Gas discharging devices 8, 9 are provided respectively on the sides of the air cooling pipe groups 6, 7. Enclosure plates 10, 11 are provided respectively below the air cooling pipe groups 6, 7, and a sprinkler box 12 having a U-seal is provided between the enclosure plates 10, 11 and therebelow.
Drain thus heat-exchanged and condensed by the cooling pipe bundle 2 as the steam flows is collected at the center of the pipe bundle 2 and flows into the below sprinkler box 12 through between the air cooling pipe groups 6, 7 enclosed by the enclosing plates 10, 11, then falls through the U-seal into a hot well 13 which is a lowermost part of the condenser body 1 and discharged outside through a drain exit 14.
On the other hand, uncondensed gases, such as steam which could not be condensed by the cooling pipe bundle 2, air, etc. flows through the air cooling pipe groups 6, 7 horizontally toward the outside of the condenser body to be discharged to the outside of the condenser body 1 through an air exhaust pipe 15 via the gas discharging devices 8, 9.
Because the air exhaust pipe 15 is connected to the outside of the air cooling pipe groups 6, 7 as described above, drain generated in the air cooling pipe groups 6, 7 tends to intrude the air exhaust pipe 15. For the purpose of prohibiting the drain intruding the air exhaust pipe 15 as described above from residing in the air exhaust pipe to return to the sprinkler box 12, the air exhaust pipe includes a vertical piping or an inclined piping portion to lead the uncondensed gas upward, whereby exhaust of the uncondensed gas is smoothed, and downstream machines and instruments are protected from erosion and corrosion. Accordingly it is necessary to arrange the air exhaust pipe extended upward along the sides of the cooling pipe bundle 2.
The drain once intruded the air exhaust pipe is sometimes carried against the gravity by the uncondensed gas in the air exhaust pipe when the uncondensed gas has a high flow rate. In addition, pressure loss increase much affects achievement of the condenser. Accordingly, thick pipes are used for low flow rates.
However, the sides of the cooling pipe bundle 2 are places where the steam which has flowed from upward flows into the cooling pipe bundle 2. In these places the flow passage has a most restricted area by the cooling pipe bundles 2, and the steam has a highest flow rate.
Accordingly it causes pressure loss increase to dispose the air exhaust pipe 15, which is to be a barrier, in such a high flow rate area. As a result of that, the outlet pressure increase of the turbine occurs. Resultant problems are that effective use of thermal energy is affected, and others. The air exhaust pipes 15 must be arranged extended between the cooling pipe bundles and between the cooling pipe bundle and the condenser body, which results in the increased width of the bottom of the condenser body 1. Problems are that the condenser cannot be compact, and others.
In view of the above-described problems, the present invention was made, and an object of the present invention is to provide a condenser which can prevent pressure loss of steam flow due to the air exhaust pipe, prevent thermal energy loss, and can be compact.