US2224877A - Condensing apparatus - Google Patents

Description

Dec. 17, 1940. J, w. MCNULTY 2,224,877 v CONDENSING APPARATUS Filed'Aug. 25, 1939 6 INVENTOR Joan M McMurry.

a, R M

3 ATTORNEY Patented Dec. 17, 1940 UNITED STATES 2,224,877 7 CONDENSING APPARATUS John W. McNulty, Prospect Park, Pa., assignor to Westinghouse Electric & Manufacturing C'om- I pany, East Pittsburgh, Pa., a corporation of. I

' Pennsylvania Application August 25, 1939, Serial No. 291,808 2 Claims. (01. 257-2) Psr1"r.1 11 OFFICE bining the output of central stations with thesteam and power demands of industrial plants.

In some plants hot water is required for process work as well as for make-up, and it is frequently desirable to keep the hot water in a closed system as where it has been treated, or must be kept free from contamination.

In power plants where large quantities of steam are required for process work, the turbines may operate primarily as steam reducing valves in order to supply the large amounts of steam,

necessary, in which case the steam flow through the low-pressure turbines is limited to that required for keeping the turbines cool, and the heat taken from the turbines'may' be, in turn, absorbed and recovered by passing the steam through a condensing plant of the type'hereinafter disclosed.

Therefore, it is an objector the invention to provide a condensing plant comprising a plurality of heat exchangers with the cooling medium for one or more of the heat exchangers in a closed system independent of the cooling medium of the remaining heat exchangers.

A further object of the invention is the provision of a condensing plant including a'main condensing unit and one or more heaters forwater in a closed system adapted to flow through the heaters, together with a damper structure for directing exhaust steam from a, turbine to the heaters and for passing any excess steam to the main condensing unit.

Another object of the invention is the provision of a condensing plant comprising a condenser and a heater, the liquid to be heated in the latter being in a closed system, together with counterweighted pivotally-mounted dampers normally closed to direct an adequate supply of turbine exhaust steam to the heater and automatically moving to open position to permit flow of any excess steamto the condenser.

These and other objects are efiected by my invention as will be apparent from the following description and claims, taken in connection with stituting an air cooler 21.

the accompanying drawing forming a part of this application, in which:

Fig. 1 is a transverse sectional View taken through a condensing plant embodying the invention;

Fig. 2 is an enlarged sectional view taken along the line lI -lI of Fig. 1 looking in the direction of the arrows; 1

Fig.- 3 is an enlarged detail view of a portion of the structure'sho-wn in Fig. 1; and,

Fig. 4 is a somewhat schematic view showing a modified'control' arrangement for the appa-.

ratus. Referring now to the drawing more in detail, there is shown, at 10,: a condensing plant comprising a main condenser l l and a pair of heaters 12 which, in the interest of low first cost, are preferably disposed exteriorly of the main condenser structure, although satisfactory results I may be obtained by positioning the heaters within the shell of the main condenser.

In the preferred embodiment herein shown, the main condenser comprises a shell l3 having an exhaust steam inlet I4 and a'condensate trap I5 provided with a condensate outlet l5a. A plurality of tubes I! extend lengthwise of the shell and define a tube nest l8. A groupof tubes at the center. of the nest are separated from the remaining tubes by a baille structure l9 provided with openings for the passage of, noncondensable' gases, these separated tubes con- An airi offtake 22 provides for the discharge of .non-condensable gases to the exterior of the shell I3.

The shell l3 extends above the tube nest It a material distance to provide a. steam inlet chamber 25 provided with opposed openings 25 in its side walls communicating with conduits 2'! which, in turn, open into the pair of heaters l2.

Each'heater I2 is comprised by a cylindrical shell 29 adapted to receive steam from the steam inlet chamber 25 of the main condenser ll through the condu'itZl, and having a condensate and non-condensable gas outlet 30 communicating, through a conduit 3|, with the interior of the maincondenser shell l3. A'plurality of tubes 32 comprise the tube nest -33-within the shell 29 and the baffle 34 separates the tube nest into'a condensing portion 35 and an air cooling portion 3% the latter communicating with the condensate outlet 30 of the shell 29.

The baffle 34 is provided, at its lower edge, with openings 31 providing for unobstructed flow of condensate to the outlet 30. The free edge of the baffle is positioned near to but spaced from,

that wall of the shell 29 which is opposed to the steam inlet opening thereof.

In the interests of economy, it is desirable to maintain a higher temperature and pressure Within the heaters than is present in the main condenser to provide for absorption of the maximum amount of heat in the heaters which, in turn, provides for reduction in the losses that would occur if this heat were absorbed and dislO tributed through the circulating Water of the main condenser. This is particularly true where the circulating water in the heaters is to serve as make-up water for the boilers or is specially treated water for process work or similar uses. In order to insure an adequate supply of steam for the heaters at all times, means are provided within the steam inlet chamber of the shell |3 for directing steam to the heaters and maintaining elevated steam pressure and temperature over the heater tube surface, under conditions of relatively small quantity of steam flow, and for by-passing any excess steam to the tube nest l8 of the main condenser.

In the preferred.embodimentthis means constitutes a pair of dampers fixedly mounted on shafts 4| extending horizontally adjacent opposite sides of the steam inlet chamber 25 with their ends carried by ball bearings 42 mounted in the shell l3. Preferably, one end ,of the shaft 4| extends outwardly beyond a wall of the shell and is provided with a handwheel 43, or similar manually operable means, for a purpose to be hereinafter described. Leakage of steam past the outwardly-extending portion of-the shaft 4| is prevented by the labyrinth seal gland 44, of conventional structure.

Each damper 40 is connected by a link 46 to a counterweight 41 pivotally mounted on a shaft 48 extending parallel to the shaft 4|. When the 40 steam flow through the condensing plant is slight, the counterweights 4| maintain .the

dampers 4|) in horizontal closed position with their outer edges in abutting relation to the under surface of the plate 49. When the amount of steam discharged into the steam inlet chamber 25 exceeds the capacity of the heaters, the steam pressure forces the dampers 40 downwardly and outwardly to open position, thereby raising the counterweights 41 to the dotted line 50 position shown. The counterweights may be adjusted to provide for any desired differential in pressure between the heaters and condenser before they begin opening. This tends to always give the heaters an adequate steam supply at the desired temperature and pressure. As best shown in Fig. 3, the counterweight 41 is carried past the vertical position, thereby locking the dampers 40 open. A pair of lugs 50 at the inner end of each counterweight prevents movement of the 0 counterweight to or past dead center position sufficient to force the dampers 40 to wide open position. However, the dampers will give some throttling effect before they fly open. This would take care of possible fluctuating demands of the heaters due to possible fluctuating water quantity or inlet temperature.

In Fig. 4, there is shown an alternate arrangement wherein manual control of the dampers is omitted and means are provided for adjusting the dampers in accordance with the amount of steam supplied to the turbine.

To this end, the main condenser H and heaters l2 are connected With the exhaust flange 55 of the turbine 56, the latter being provided with a governor mechanism 51 for controlling the admission of motive fluid to the steam chest 58. The linkage arrangement 59, 59a and 60 serves to transmit motion from the governor to a relay or servo-motor 6|, the latter, through the bell crank 62 and leverage 63, B4, and 65 serving to rotate the shafts 4| to open or close the dampers 40. With this arrangement, any change in the volume of steam supplied to the turbine immediately effects the damper adjustment in ad- Vance of the actual change in steam conditions within the steam inlet chamber 25.

It should be noted that the dampers serve a two-fold purpose. First, they separate the heater from the condenser, thus making it possible to control the pressure, and therefore the temperature, over the heater surface, independent of the pressure in the condenser at low steam loads. Second, they act as a relief valve in case of a sudden increase in steam flow, dumping the steam into the main condenser and thus preventing a serious increase in pressure at the turbine exhaust.

While I have shown my invention in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modificationswithout departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. In a condensing plant; a surface condenser comprising a shell having an exhaust steam inlet at the top and a condensate outlet at the bottom, and a nest of tubes Within the shell and positioned a material distance below said exhaust steam inlet to provide a steam inlet chamber above the tubenest; a surface type heater; a conduit providing communication between the heater and the inlet chamber; and means in said inlet chamber for apportioning the amount of steam passing to the condenser tube nest, said means comprising a plurality of pivotallymounted dampers adapted when closed to direct an adequate supply of steam to the heater and to automatically open to whatever degree required to pass any excess steam to the condenser tube nest when the pressure differential between the inlet chamber and the tube nest exceeds a predetermined value.

2. A structure as specified in claim 1, including means for automatically locking the dampers in maximum open position and means operable from externally of the condenser for manual release of the dampers from locked open position.

JOHN W. MCNULTY.

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