US3068653A - Unitized arrangement of auxiliaries in power system generation - Google Patents

Description

UNITIZED ARRANGEMENT OF AUXILIARIES IN POWER SYSTEM GENERATION Filed Oct. 14, 1960 Dec. 18, 1962 J. M. DRISCOLL 4 Sheets-Sheet 1 INVENTOR. law 17. De

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UNITIZED ARRANGEMENT OF AUXILIARIES IN POWER SYSTEM GENERATION 4 Sheets-Sheet 3 Filed Oct. 14, 1960 M0050 5.105 g Wbkg menu 1 I l l I I l Wbk ll'lll.

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,4 rrogwsys BY W SR (\W VUO FunkWwSut wroiom YSQ EXTPPEBW 1386- 1962 J. M. DRISCOLL UNITIZED ARRANGEMENT OF AUXILIARIES IN POWER SYSTEM GENERATION Filed Oct. 14. 1960 4 Sheets-Sheet 4 wowaom DOQQW om vii O WV fi q L mw an fi "W1 1 3 i won .m 8 on m N m m v I E m n FN m m 5 INV EN TOR JOHN M D SQOLL Inn 3,068,653 UNETEZED ARRANGEMENT F AUXELHARIES EN PGWER SYTEM GENERATll-CEN John M. Driscoii, Manhasset, N.Y., assignor to Consolidated Edison Company oi New York, lnc., New York, N.Y., a corporation of N ew York Filed Get. 14, 1960, 3er. No. 62,550 16 Claims. (Cl. 60-70) This invention relates to steam driven power generating systems which incorporate means for recycling steam condensate through the system for reuse. More particularly, the invention relates to the selection and arrangement, with respect to other apparatus of the system, of the auxiliary apparatus needed to effect return of steam condensate from an exhaust steam condenser back to the conventional boiler feed-Water pump and thence to the steam generator to again serve as feedwater therein, and to promote efiective condenser operation.

The invention was made during the course of investigations relating to the installation, maintenance, and improvement of efliciencies of a comparatively large, landbased electric power generating system and, for convenience, will therefore be described in connection with such use. However, it will be understood that, in its broad aspects, the invention is adaptable for use in all systems of the type described, whether they be land or marine installations.

Describing a typical electric power generating system which will be used herein only as an example of a system into which the invention may be incorporated, two electric generators are steam turbine driven to produce an electric power output. In a cross-compound turbine arr-angement, one generator is driven by the high pressure and intermediate pressure turbines, being coupled to the common output shaft of the two. The other generator is coupled for rotation to the shaft of the low pressure turbine. Of course, a tandem-compound turbine arrangement might be alternatively employed.

High pressure, superheated steam from a steam generator, or boiler is led sequentially through the high pressure, intermediate pressure and low pressure turbines (or stages, as they are sometimes referred to), the steam exhaust from one stage being used to drive the succeeding stage. The steam is finally exhausted from the low pressure turbine into a condenser, located below the engine room floor, where it is condensed as it passes over condenser cooling tubes therein and accumulated, as main steam condensate, in a hotwell located at the bottom of the condenser. The tubes of the condenser are cooled by condenser circulating water pumped therethrough from a cool water source, such as a river, a lake, the sea, or any such supply of water, or recirculated from a cooling tower or the like. From the hotwell, the condensate is pumped by main condensate pumping apparatus through one or more boiler feedwater heaters to the suction side of a boiler feedwater pump by which it is delivered, perhaps through additional feedwater heaters, to the boiler to be again generated therefrom in the form of steam. As is commonly understood, the condensate upon emergence from the main condon sate pumping apparatus is referred to as boiler feedwater. Reuse of main steam condensate as feedwater for the boiler promotes system efficiency, as is well known.

Prior to its entry into the feedwater heater or heaters, the relatively cool main condensate is often used as a coolant by passing it through various types of heat exchange apparatus appropriately situated in the line of flow. For example, in a conventional arrangement, the condensate will be used to cool a multistage steam jet air ejector which is connected to the condenser for promoting 3,%8,653 Patented Dec. 18, 1962 ice a vacuum atmosphere in the steam space therein, and to cool lubricating oil flowing through oil cooler apparatus. In an electrical power generating system, the condensate may also be passed through hydrogen coolers for cooling the hydrogen gas conventionally circulated through the electric generator during normal operation. These econ omies, which are derived by effecting a heat exchange between media which must be cooled and a fluid which, in any event, is intended to be heated, will continue to be obtainable in a system which incorporates the present invention.

Some of the more troublesome concerns in designing a power generating system are the selection and arrangement with respect to other system apparatus of the auxiliary pumping apparatus which must be employed to pump the main condensate from the comparatively low elevation of the condenser hotwell to the higher elevations of the boiler feedwater heaters and pump, as aforesaid, and to pump condenser circulating Water from the cool water source through the cooling tubes of the condenser. Salient factors for consideration in these respects are the effects of such selection and arrangement upon'initial installation and subsequent maintenance costs, and upon the reliability, effectiveness and efficient operation of the selected auxiliaries and of the overall system. The customary types and arrangements of other system apparatus affect many of these factors and, consequently, the selection and arrangement of the referred-to auxiliaries. It is to an effective solution of these problems of selection and arrangement that the present invention is particularly directed.

Since pumping effectiveness and efficiency is affected by height, proper selection and arrangement of main condensate and condenser circulating water pumping apparatus for use in a recycling system will be largely a determination based upon a consideration of the differences in elevation between the customary locations of the system main engines, the boiler, the boiler feedwater heaters, the boiler feedwater pump, and the main steam condenser including the elevation of the hotwell thereunder. Moreover, Whether or not a direct-contact feedwater heater is employed will also affect the selection and arrangement for the reason that, among other things, a direct-contact type feedwater heater, such as a deaerating feed heater, effects what will be herein referred to as an open system with accompanying changed conditions of line operating pressure, and of the most propitious elevational location at which such a heater will operate in association with the boiler feedwater pump, as compared to these factors as they are involved in the operation of the alternative closed system which includes only shell and tube type heaters. As will be commonly understood, all of these considerations are manifest to a pronounced degree in the design of comparatively large power generating installations.

Accordingly, in the case where either an open system or a closed system is intended, and in consideration of the aforesaid design problems presented by inherent elevational differences, systems designers have heretofore believed that main condensate pumps and condenser circulating water pumps are best located at elevations approximating that of the floor level under the condenser. Because it has been believed that these elevational locations are essential for proper operation, and although it is known that main engine power is available, or may be increased to provide direct take-off drive power for system auxiliaries in general, it has not been understood how the main condensate and the condenser circulating water pumping apparatus in particular might be selected and arranged so that they, or either of them, might be so driven.

pump in the line.

Conventionally, therefore, and as is preferred over auxiliary steam or gas powered equipment for the purpose, electric motors are employed as the means for driving both the main condensate and the condenser circulating water pumps. Usually at least two relatively large electric motors are used to drive the two vertical type main condensate pumps which are conventionally attached in parallel arrangement in the condensate flow line, a third electric motor driven pump unit sometimes being provided as a standby in a line by-passing the two main pumps. To circulate cooling water in the condenser, two electric motor driven, either vertical or horizontal type condenser circulating water pump units are employed, these also being connected in parallel arrangement. 7

As system electric power output capacity is increased, the capacity and power requirements of the referred to pumping apparatus increases correspondingly, and their operating conditions change. As a result, larger size electric motors having different characteristics of operation must be used. Moreover, the associated wiring and motor-control apparatus become more complex and susceptible to breakdown during operation. Initial installation and subsequent maintenance costs become proportionally greater. In the case of the circulating water pumps, for example, the much larger motors which are required, and which operate at comparatively low speed, are very expensive. Because similar problems arise, and still additional problems are introduced, reversion to other types of independent drive means does not always effectively solve these problems.

By the preferred embodiment of the present invention, however, a single, high powered and high speed horizontal type main condensate pump is driven by either direct or reduction gear connection to the output drive shaft of one of the main turbine engine units. Contrary to known acceptable practices, the main condensate pump will be located at approximately the elevation of the engine room floor. A comparatively low powered separately driven hotwell booster pump, located at the condenser fioor level such that its suction opening is below the level of the water in the hotwell, is used to boost the condensate, usually first through the aforementioned condenser air ejector, oil coolers, hydrogen coolers and the'like, to the main condensate pump which provides the main pumping action to deliver the condensate to the boiler'feedwater heaters and thence to the boiler feed pump as previously described.

To assure an effective supply of feedwater to the boiler feed pump only during a startup of the system fromfa. cold condition as distinguished from a relatively hot restart condition, and particularly where the system is an open type, a second hotwell booster pump, referred to herein as a startup auxiliary hotwell booster pump and havingdiflerent characteristics of operation from the primary hotwell booster pump, is installed in a location similar to that of the primary hotwell booster pump but in a main condensate bypass line arrangement for pumping the small quantities of condensate initially produced in the condenser eventually to the boiler feed pump. The startup auxiliary booster pump is a comparatively small, .motor driven pump which will operate under relatively higher head as compared with the primary, or regularly on-line hotwell booster pump, and the by-pass line in which it is installed may be arranged so that the initial condensate passes through the auxiliary cooling apparatus and the main condensate pump, or any of them, or not, prior to its entry into a feedwater heater stage which'precedes the boiler feed For circulating cooling water in the condenser, a single, highpowered and low speed vertical type condenser circulating water pump, at an elevation approximating that of the condenser floor level as determined by pump operating conditions, will also be driven by power take-- generally indicated by numeral 12.

oil, through a reduction and bevel gearing arrangement and an elongated, vertically extending pump drive shaft, from the output drive shaft of one of the main turbine engine power units.

As a result of the selection and arrangement in accordance with the invention of these auxiliaries, extraordinary savings in initial installation costs of the system are achieved, and maintenance requirements are substantially reduced. For example, as compared to the cost of installing a 400,000 kilowatt output capacity electric power generating system which employs conventional electric motor driven main condensate and condenser circulating water pump units, including their associated auxiliary electric power supply and control apparatus, one calculation by experienced engineers showed that a saving of more than $500,009 can be obtained by selecting and arranging the main condensate and circulating water pumps, and the system, in accordance with the present invention. Moreover, subsequent operating costs will have been considerably reduced by reason of the employment of pumping power which is developed at substantially the efficiency of the main engine units, which efficiency is high as compared with elficiencies which would result from the use of the otherwise necessary electric drive and electric auxiliary apparatus. These savings will be obtained whether the system adopted is either a so-called open system or a closed system, the invention being adaptable for use in both systems.

As'will become apparent, the system as a whole in any of its modified forms will be susceptible to easy and efiicient startup.

These and other objects and features of the invention will become more readily apparent from the following description of preferred embodiments thereof, when taken together with the accompanying drawings, in which:

FIGURE 1 is a schematic illu;tration, in perspective, of an electric power generating system arranged and constructed in accordance with the invention;

FIGURE 2 is a schematic plan view of a similar power generating system;

FIGURE 3 is a schematic side elevational view of the system for reference in association with FIGURE 2, certain apparatus which normally would be hidden from view by other apparatus appearing displaced from their actual locations, for clarity;

FrGURE 4 is a schematic plan view showing a moditied form of the invention; and

FIGURE 5 is a schematic side elevational view similar to FlGURE 3 illustrating still other modified forms o the invention.

It will be understood, of course, that the accompanying drawings are intended to serve as schematic illustratlons only 'of a system incorporating the preferred embodiments of the invention to be described, the detailed arrangements and construction of each of the items of eq p ment being familiar to those having ordinary skill in the art, and that the hereinafter referred to operating characteristics of the equ'pment itsems should be conidered only a examples used for the purpose of clarity in the following description;

Referring generally to all of the figures of the drawings, a typical power generating system has a steam generator or boiler 10, including a steam and water drum 11, f r generating steam to drive a main engine means which is In the examples shown, the main enginemeans comprises a three-stage steam turbine arrangement, including a high pressure turblue 13, an intermediate pressure turbine 14, and a lo pressure turbine 15. As indicated by the arrows, the steam from the steam generator flows sequentially through each of the turbine stages, sometimes'being passed through reheaters (not shown) therebetween, the exhaust from the preceding stage being used-to drive both the intermediate pressure and low pressure stages. The steam finally exhausts from the low pressure stage into a condenser 16 which is located therebelow. In conventional cross-compound arrangement, the high pressure and intermediate pressure turbines are connected so as to rotate a c mm n power output drive shaft 17a, whereas the low pressure turbine causes rotation of another power output drive shaft 17b to which it is connected. Of course, the rotating drive shafts 17a and 17b, which turn in response to rotation of the turbines, comprise the source of power generated by the system.

Further as is conventional, the main steam exhaust from the engines passes over cooling tubes 18 within the main steam condenser 16, the cooling effect thus imparted causing the steam to condense and accumulate in a hotwell 19 located at the bottom of the condenser. As is well known, the condensed steam is referred to as main steam condensate, and its accumulation in the hotwell is for the purpose of creating a source of suction for the pumps which will be required in any recycling system to return the water to the steam generator so that it may be again generated therefrom in the form of steam to drive the main engine means 12. The condensate is pumped from the hotwell through a main condensate flow line 20 eventually to a boiler feedwater pump 21 which feeds the water to the steam generator under pressure sufiiciently high to overcome the internal operating pressure of the steam and water drum 11. Since the condensate as it emerges from the condenser 16 is quite cool, it is conventionally used for cooling purposes in auxiliary heat exchange apparatus of the system, such as oil cooler 22 and, in the case of electric power generating system, hydrogen coolers 24 located either within or outside of the generator framework. Moreover, it is a usual practice to also pass the condensate through a multi-stage steam jet air ejector 23 which is conventionally connected to the condenser for the purpose of augmenting the condensing action of the steam in producing and maintaining the necessary vacuum atmosphere within the condenser steam space. Use of the relatively cool rnain steam condensate as a co lant in all of these heat exchange apparatus promotes economy of operation of the system by eliminating the need for separate cooling water pumping systems for the urpose, and because further economy will be effected by preheating the condensate before it is pumped into the steam generator. Thus, after the condensate has been passed through one or more heat exchangers, it is conventional to additionally heat it in one or more feedwater heaters 25 located in the line ahead of, and beyond the feedwater pump 21, as indicated by the drawings.

Depending upon heat balance and other factors of operation of the system, one of the feedwater heaters in the line may or may not be of a direct contact type, and such selection will alter the conditions of flow of the condensate. Whereas, if all of the heaters are of a shell and tube type the presence of the heaters do not effect a significant increase in pressure in the line, an open type heat r, such as a deaerating type feedwater heater, will present additional pressure in the line against which the fluid must be pumped, depending on the type used. Thus, as is generally understood, the particular type of feedwater heater which is selected will also affect the conditions of operation of the pumping apparatus employed to cause the condensate flow therethrough. In FIGURES l and 5, a deaerating type feedwater heater a is indicated as being in the line.

In a conventional electric power generating installation for developing about 400,000 kilowatts of electric power, as the drawings may be considered as illustrating, the turbine drive shafts 17a and 171') are directly coupled, as by coupling means 26, to the electric power generators 27a, 2% respectively, thereby driving the same to convert the mechanical power output of the turbines to electric power. In the system of the present example, which is operated by high pressure, superheated steam, the high pressure and intermediate pressure drive shaft 17a will rotate at 3600 rpm. (revolutions per minute) and the low pressure drive shaft 17b at 1800 r.p.m., the shafts each developing about 280,000 I-LP. (horsepower). It is therefore gen erally known that power in excess of that which is required to drive the generators is available, or can be produced on these main engine drive shafts to drive auxiliary equipment, provided the equipment, as judged by its characteristics and conditions for operation, can be located proximate to either of the shafts. For example, since for best operation the feedwater pump 21 is preferably located at approximately the elevation of the steam generator 10, and further for the reason that the feedwater pump 21 will require high power and high speed, this auxiliary is well suited to be directly driven by attachment to an extension of the high pressure and intermediate pressure drive shaft 17a. Of course, the feedwater pump 21 might also be directly coupled to the low pressure turbine drive shaft 17b for the same purpose. However, because the level of elevation of the hotwell is as much as thirty-five to forty feet below that of the engine room, it has not been generally understood that a main condensate pump and a condenser circulating water pump, both of which are conventionally required in such a system as has been described, might also be coupled to the drive shafts.

Thus, conventional main condensate pumping apparatus which would be replaced by the present invention usually consists of at least two relatively large, electric motor driven, vertical type main condensate pumps located at the hotwell level to pump the main condensate from the hotwell through the auxiliaries 22, 23 and 24, up to the elevated location of feedwater heaters 25 and heater 25a, where included, from which it will flow to the suction side of the feedwater pump 21. Each of these parallel-arranged main condensate pumps requires about 700 to 750 H.P. and operates at a speed of about 1800 r.p.rn. Together, they deliver 5000 g.p.m. (gallons per minute) of condensate to the feedwater heaters and boiler feed pump. In an open system where the feedwater heater 25a is conventionally located about feet above the hotwell level, the main condensate pumps operate against a total dynamic head of about 800900 feet.

It should be understood that total dynamic head of fiuid against which a pump must operate is commonly measured as converted to feet of water under hypothetical static conditions. Total dynamic head is determined by such factors as the specific weight of the fluid, the static height to which it must be pumped, friction losses in the fluid flow line, and internal operating pressure of the apparatus into which the fluid is to be introduced. In the instant case, for example, the deaerating type feedwater heater 25a will normally be located at a static height of 135 feet above the hotwell level and 10-0 feet above the engine room floor level, and may normally operate under an internal pressure of about psi. (gage).

Similarly, the apparatus commonly employed to introduce and circua-te cooling water through the tubes 1% of the condenser 16 usually consists of two 600 HP. electric motor driven vertical type condenser circulating water pumps generally located at the condenser floor level. These pumps lift the cooling water from the elevation of the natural, or other cool water source to the level of the condenser. Thus, the pumps ordinarily operate against a total dynamic head of about 15 to 30 feet to supply the relatively large volume of water, about 250,000 g.p.m., to the condenser. As is Well known, low speed pumps, operating in the neighborhood of about to r.p.m., are more commonly employed but are expensive, for the purpose.

Referring now to FIGURES l-3, it is seen that, according to one embodiment of the present invention, a single, horizontal type main condensate pump 28 is located at the elevation of the engine room floor and is connected in driven engagement with the power output drive shaft 175 of the low pressure turbine 15. The main condensate pump 23 may be a two stage pump directly coupled, as by coupling means 29, to the drive pinion 30 of a reduction gear chain which is generally indicated by the numeral 31. As arranged in FIGURES 4 and 5, however,

the main condensate pump 23 may be a single stage pump directly coupled, as by coupling means 32, to the power output drive shaft 17:: of the high pressure and intermediate pressure turbines (FIGURE 4), or directly coupled, as by coupling means 2.9 to a smaller, speed-multiplier pinion 30a which is driven by the drive pinion 3b of the gear chain 31 (FIGURE The number of integral stages which the pump will have is determined largely by the speed of rotation of the pump drive shaft with relation to the conditions under which the pump will operate. Thus, FIGURES l-3 indicate that a two stage pump should be used where the pump is driven at 1800 rpm. and FIG- URES 4 and 5 indicate that a single stage pump will be used where its drive shaft speed of rotation is 3600 r.p.m. In any of the arrangements shown by the drawings, the pump operates on 1500 HF. and will have the requisite 5000 g.p.m. capacity. Where the system is either closed or open but includes feedwater heaters all of which operate at low (i.e. about 50 psi.) internal pressure, the pump 28 will operate against a total dynamic head of about 700-390 feet, whereas, as illustrated in FIGURES l and 5 for example where a deaerating type fcedwater heater 25a is included, which operates under an internal pressure of about 150 psi. and which is usually located about 135 feet above the hotwell level, the main condensate pump 28 will operate against about 890-900 feet of dynamic head.

In addition to main condensate pump 28, there is provided a single, relatively low powered, separately driven hotwell booster pump 33 located at the level of the hotwell 19 and within the main condensate line 20, to supple: ment the action of the main condensate pump 28. This pump 33 maintains the pressure of the condensate flowing from the hotwell 19 in main condensate line 20 above that which would correspond to saturation vapor pressure at the temperature of the condensate and thus prevents flashing of the condensate into steam, a condition which might otherwise occur. In the preferred embodiments illustrated, the hotwell booster pump 33 is a vertical type pump driven by a 250 H.P. electrical motor 34- at a speed of about 1170 rpm. The pumping capacity is, of course, 5000 'g.p.m. which is the rate at which the condensate must be delivered to boiler feed pump 21 during normal operation. The booster pump 33 will operate against "a total. dynamic head of about.l feet in the case where I the condensate will flow through air ejector 23, hydrogen coolers 24 and oil cooler 22. prior to its delivery to the suction side of main condensate pump 23.

A single, vertical type condenser circulating Water pump 35, located at approximately the condenser floor level in circulating water flow line 42, is also connected in driven engagement with the low pressure turbine 15', the elongated pump shaft 36 extending upwardly to the engine room floor level and connectedfby bevel gearing 37 to be driven by take-0E from reduction gear chain 31. As

shown, horizontal shaft portion 37a of bevel gearing 37 may be coupled to the second reduction gear 38 of a double reduction gear chain'but, of course, other arrangements are possible. In ordinary situations and when located at the condenser floor level, the condenser circulating water pump 35 will be required to operate against only about 15 feet of dynamic head 'tocirculate lends itself to be driven through areduction gear arrange ment by reason of its comparatively low speed. Thus, it v will be found that a 10 inch diameter shaft 36,.about 30 J feet long, can be effectively used toconnect the pump for driven engagement by the low pressureturbine 15. The bevel gearing 37 may he of a helical gear type and,1furthee-finely be arranged and constructed, as shown, to itself provide speed reduction such as would be in addition tothat speed reduction derived from the comparative diameters of the gears in reduction gear chain 31. Of course, as in the case of main condensate pump 28, it will also be understood that the exact manner by which the pump 35 'is connected to main engine means 12 will be determined by the torque converter apparatus employed, of which a reduction gear chain is only a particular type. In addition, it will be understood that, pro-- vided adequate speed reducing means may be effectively arranged, the condenser circulating water pump 35 might alternatively be driven by connection to the high pressure and intermediate pressure turbine drive shaft 17a.

Thus, a number of main engine power takeofi arrangements for both the main condensate pump 28 and the condenser circulating water pump 33 are possible, once the principles of the invention are understood. Such alternative arrangements will be apparent to those having skill in the art.

For starting the system from at rest condition, a relatively large auxiliary steam jet air ejector 39, sometimes referred to as a hogger, is connected to the steam space of the condenser 16 to initially evacuate the entire steam space within both the low pressure turbine casing and the condenser shell, thereby promoting a very low absolute pressure atmospheric condition therein. When an absolute pressure on the order of 15 to ZO'inches of water is reached, the normally on-line operating multiple stage steam jet air ejector 23 is put into operation to supplement the evacuating action of the auxiliary ejector 39, whereupon an absolute pressure of about 1 inch of water can be obtained promptly during startup of the system. After the startup period has elapsed, the auxiliary steam jet air ejector 39 may be deactivated, as by closing a valve 413, whereupon the multiple stage air ejector 23 will maintain the desired operating atmospheric condition within the condenser steam space.

Upon startup of the system, main steam will begin to flow from the low pressure turbine exhaust into the condenser 16 and, unless provision is made, cooling tubes 18 within the condenser will not contain circulating water at this time. In order to ehiciently start the system in operation, therefore, still another auxiliary steam jet air ejector or priming jet, 41 is operated prior to, and for a brief time interval during the startup period, this priming jet being connected to the condenser tube system 18 for creating a vacuum condition within the tubes which will cause cooling water to be drawn up from the source thereof, through condenser circulating water flow line 42, to initially fill the tubes of the condenser 16. As the low pressure turbine begins to rotate, so also will the circulating water pump 35' begin to rotate and to assume its normal operating function, whereupon the priming jet 41 may be disconnected from the condensate tube system 18, as by closing the valve 43 in its suction line. Of course, it will be understood that, in a manner similar to the operation of the conventional multistage air ejector 23 and which is well understood, the air cjectors 39 and 41 may be operated by steam from the boiler 10', the connections for which are not shown in the drawings.

Referring now to FEGURES l and 5 which illustrate the invention as embodied in an open type system incorporating a pressurized type of direct contact feedwater he er 25a, the heater 25a Willbesituated at an elevated location, as is conventional, about feet above the hotwell level and feet above the engine room fioor level. in such a system, and only for startup of the system from a cold, at rest condition Where the main engines have not been on turning gear, there is provided a comparatively small auxiliary condensate line 4 which bypasses hol /ell booster pump 33. Stop valves 45 and are appropriately placed in the auxniary condensate line and in thernain condensate line 2%, respectively, for the purpose of shunting the small 'quantitiesof condensate which are initially produced in the condenser 16 during the startup period into the bypass line 44, and for later closing ofif such by-pass flow and to establish the normal operating fiow pattern in condensate line 20 when startup has been completed. A single 15 HP. startup auxiliary booster pump 47 is located at the level of the hotwell 19 and Within the auxiliary condensate bypass line 4-4. This pump has a pumping capacity of about 150 g.p.m. of main condensate, and is separately driven at a speed of about 1800 rpm. Normally, it will be operated against a dynamic head of about 210 feet. As illustrated in the drawings, a vertical type electric motor driven pump is suitable for the purpose.

Although bypass line 44 might be arranged in parallel with all of the auxiliary heat exchange apparatus, and so that startup auxiliary booster pump 47 will pump the initially produced condensate directly either to main condensate pump 2.3 or into the feedwater heater 25a, the drawings indicate that the condensate is preferably led through the heat exchange apparatus 22, 23 and 24, as under normal operating conditions, to serve as a coolant therein, and thereafter by-passes the main condensate pump 28. Thus, as shown by FIGURES 1 and 5, the bypass line 44 includes another line portion 44a thereof, having an appropriate shut-off valve 45a therein, leading from the last of the heat exchange apparatus (in this case, oil cooler 22) to the feedwater heaters 25, includ ing feedwater heater 25a, as by again connecting with the main condensate line 26* at the discharge side of the main condensate pump 28, as shown. The main condensate line 29 will have other appropriate shut-off valves 46a and 46b to etiectuate the by-pass into line portion 44a, and to restore flow through condensate pump 28 after startup has been completed.

Upon startup of the system shown by the drawings from the cold, at rest condition, valves 46, 46a and 46b in main condensate line 20 are closed, and valves 45 and 45a in bypass lines 44, si l-a are opened and the startup auxiliary booster pump 47 is started up. As initial quantities of condensate are produced in condenser 16, they will be delivered through heat exchangers 22, 2.3, 24- and into the feedwater heaters 25, bypassing hotwell booster pump 33 and main condensate pump 28, thereby insu ing that an adequate amount of boiler feedwater is supplied to boiler feedwater pump 21 which, of course, will be rotating initially at relatively low speed. As quantities of main steam condensate begin to be produced at a rate in excess of about 150 g.p.m., valves 45a and 4617 are then opened, valves 45 and 45a are closed, and the main hotwell booster pump 33 is started up, after which startup auxiliary booster pump 47 is closed down, whereupon normal system operating conditions will have been'established.

It should be noted, however, that the startup auxiliary booster pump 47 and the auxiliary lines 44 and 44a need not be incorporated in systems which do not also incorporate a pressurized type of feedwater heater, such as a deacrator, or where startups will normally be under conditions where the system is relatively heated throughout, such as upon a hot restart where the main engines are on turning gear. This is because, under either of these conditions, it will be found that at the rate of speed at which the system may normally be started, the main condensate pump 23 will promptly develop sufficient head of pressure to insure an adequate supply of feedwater to feedzvater pump 21.

When a cold startup of the system includes bringing the main steam output of boiler up to normal temperature and pressure, during which time the main steam is preliminarily by-passed around the main engines and fed directly into the condenser, which method is commonly referred to as a controlled start, an auxiliary turning motor 43 (FIGURES) is coupled through a self-disengaging clutch 49 to circulating water pump drive shaft 35. The motor 48, being about a 30 HF. motor,

is activated upon starting the system to cause rotation of circulating water pump 33 at a speed of about 30 rpm, to assure circulation of cooling water through tubes 18 of the condenser at this time when the main engines 12, which are being turned by conventional turning gear (not shown), will be turning too slowly to promote adequate rotation of pump 33 for the purpose. Clutch 49 is any one of the well-known and commonly available types of clutches, such as an overrunning clutch, which will automatically declutch when the torque or speed of the main engine shaft to which the pump 33 is connected becomes greater than that produced by the motor. It is not considered necessary to illustrate clutch 49 in detail.

It should be noted, however, that where even a cold startup of the system is eilected under other than such controlled start conditions, motor 48 and clutch 49 are not required to be included in the system because the speed of pump 33, as developed by its normal shaft 36 and bevel gear 37 connection to a main engine power output drive shaft, will be accelerated sufficiently, as startup progresses, to supply more than enough circulating water than'is required for the initial steam condensing duty. In other words, excepting under controlled start conditions, the circulating pump 35 is selfsupporting, and needs no auxiliary drive.

Thus an electric power generating system has been described, in several of its embodiments, which will achieve all of the objects of the invention.

What is claimed is:

1. A power generating system comprising a steam generator, main engine means including a rotatable power output shaft at one elevation, means for delivering steam from said steam generator to said main engine means for driving the latter to produce such power, condenser means for receiving and condensing into main steam condensate the steam exhaust from said main engine means, said condenser means including a hotwell for accumulating such main steam condensate at an elevation which is substantially below said elevation of the power output shaft, and means for delivering such main steam condensate from said hotwell to said steam generator, the last said means comprising a main condensate pump connected in driven engagement with said power output shaft and located substantially at said elevation of the power output shaft.

2. A power generating system according to claim 1 wherein said main engine means comprises cross-cornpound arranged steam turbine means including a low pressure turbine unit, said power output shaft being driven by said low pressure turbine unit.

3. A power generating system according to claim 1 wherein said main engine means comprises steam turbine means including a plurality of tandem-arranged turbine units, said power output shaft being driven by said plurality of turbine units.

4. A power generating system according to claim 1 wherein said means for delivering such main steam condensate from said hotwell to said steam generator further comprises booster pump means located between said hotwell and said main condensate pump and substantially at said elevation of the hotwell, said booster pump means being adapted to prevent such main steam condensate from flashing into steam.

5. A power generating system according to claim 4 wherein said booster pump means comprises a low powered hotwell booster pump, and means by-passing said low powered hotwell booster pump including a still lower powered startup auxiliary hotwell booster pump and bypass operating valve means.

6. A power generating system according to claim 1 wherein said means for delivering such main steam condensate from said hotwell to said steam generator further comprises a low powered hotwell booster pump, means by-passing said low powered hotwell booster pump inaccuses eluding a still lower powered startup auxiiary hotwell booster pump and bypass operating valve means, said hotwell booster pump and said auxiliary notwell booster pump located between said hotwell and said main condensate pump and substantially at said elevation of the liotwell and adapted to prevent such main steam condensate from flashing into steam, and means by-passing said main condensate pump including other by-pass operating valve means.

7. A power generating system comprising a steam generator, crosscompound arranged steam turbine means including a hi h pressure turbine unit and an intermediate pressure turbine unit having a common rotatable power output shaft at one elevation, means for delivering steam from said steam generator to said steam turbine means for driving the latter to produce such power, condenser means for receiving and condensing into main steam condensate the steam exhaust from said steam turbine means, said condenser means including a hotwell for accumulating such main steam condensate at an elevation which is substantially below. said elevation of the power output shaft, and .means for delivering such main steam condensate from said hotwell to said steam generator, the last said means comprising a boiler feedwater pump and a main condensate pump, said boiler feedwater pump and said main condensate pump connected in driven engagement with said power output shaft and located substantially at said elevation of the power output shaft.

8. A power generating system comprising a steam generator, main engine means including a rotatable power output shaft at one elevation, means for delivering steam from said steam generator to said main engine means for driving the latter to produce such power, condenser means for receiving and condensing into main steam condensate the steam exhaust from said main engine means, said condenser means including a hotwell for accumulating such main steam condensate at an elevation which is substantially below said elevation of the power output shaft, means for circulating cooling water in said condenser means including a condenser circulating water pump located substantially at said elevation of the hotwell and means connecting said circulating water pump in driven engagement with said power outputshaft, and means for delivering such main steam condensate from said hotwell to said steam generator, the last said means comprising a main condensate pump connected in driven engagement with said power output shaft and located substantially at said elevation of the power output shaft.

9. A power generating system according to claim 8 wherein said power output shaft is horizontally disposed, and said means connecting said circulating water pump in driven engagement with said power output shaft conprises a vertically disposed drive shaft of said circulating water pump, said drive shaft extending from said circulating water pump to substantially said elevation of the power output shaft, and bevel gear means between said drive shaft and said power output shaft.

10-. A power generating system according to claim 9 wherein said means connecting said circulating water pump in driven engagement with said power output shaft further comprises speed reduction gear means between said drive shaft and said power output shaft, said speed reduction gear means including said bevel gear means.

11. A power generating system comprising a steam generator, cross-compound arranged steam turbine means including a high pressure turbineunit, an intermediate pressure turbine unit and a' low pressure turbine unit, said high pressure, and intermediate pressure turbine units having a common rotatable power output shaft at one elevation and said lowpressure turbine unit having a rotatable power output shaft substantially at said one elevation, means for. delivering steam from said steam generator .to said steam turbine means for driving the latter to produce such power, condenser means for re ill i2; ceiving and condensing into main steam condensate the steam exhaust from said steam turbine means, said condenser including a hotwell for accumulating such main steam condensate at an elevation which is substantially below said one elevation, means for circulating cooling water in said condenser means including a condenser circulating water pump located substantially at said elevation of the hotwell and means connectingsaid circulating Water pump in driven engagement with said power output shaft of the low pressure turbine unit, and means for cleliv'erin such main steam condensate from said hotwell to said steam generator, the last said means comprising a main condensate pump connected in driven engagement with said common power output shaft of the high pressure and intermediate pressure turbine units and located sbstantially at said one elevation.

12. A power generating system comprising a steam generator, main engine means including a rotatable power output shaft at one elevation, means for delivering steam from said steam generator to said main engine means for driving the latter to produce such power, condenser means for receiving and condensing into main steam condensate the steam exhaust from said main engine means, said condenser means including a hotwell for accumulating such main steam condensate at an elevation which is substantially below said elevation of the power output shaft, means for delivering such main steam condensate from said hotwell to said steam generator, and means for circulating cooling water in said condenser means including a condenser circulating water pump located substantially at said elevation of the hotwell and means connecting said circulating water pump in driven engagement with said power output shaft.

13. A power generating system according to claim 12 wherein said power output shaft is horizontally disposed, and said means connecting said circulating water pump in driven engagement with said power output shaft comprises a vertically disposed drive shaft of said circulating water pump, said drive shaft extending from said circulating water pump to substantially said elevation of the power output shaft, and bevel gear means between said drive shaft and said power output shaft.

14. A power generating system comprising a steam generator, main engine means including a rotatable power output shaft at one elevation, means for delivering steam from said steam generator to said main engine means for driving the latter to produce such power, condenser means for receiving and condensing into main steam condensate the steam exhaust from said main engine means, said condenser means including a hotwell for accumulating such steam condensate at an elevation which is substan'hc v below said elevation of the power output shaft and fa trier including normally operating air ejector means for evacuating the steam space of said condenser means,

means for circulating cooling water in said condenser means including a condenser circulating water pump located substantially at said elevation of the hotwell and means connecting said circulating water pump in driven engagement with said power output shaft, means for delivering such steam condensate from said hotwell to' said steam generator, the last said means comprising a main steam condensate pump connected in driven engagement with said power output shaft and located substantially at said elevation of the power output shaft and further comprising a low-powered hotwell booster pump located betv said hotwell and said main condensate pump and substantially at'said elevation of the hotwell, and startup means for said power generating system'c-omprising wherein said means for delivering such main steam condensate from said hotwell to said steam generator further includes a feedwater heater of a pressurized type, and said startup means for said power generating system further comprises means by-passing said low-powered hotwell booster pump including a still lower-powered startup auxiliary hotwell booster pump and by-pass operating valve means.

16. A power generating system according to claim 14 wherein said startup means for said power generating system further comprises means by-passing said lowpowered hotwell booster pump including a still lowerpowered startup auxiliary hotwell booster pump and bypass operating valve means, and auxiliary turning means 14 connected to said condenser circulating water pump drive shaft for driving said condenser circulating water pump during the time of startup of said power generating system, said auxiliary turning means including automatically disengageable clutch means for disengaging said turning means at the end of said startup time.

References Cited in the file of this patent UNITED STATES PATENTS 1,093,145 Pagel Apr. 14, 1914 2,101,676 Guildhauman Dec. 7, 1937 2,175,884 Doran Oct. 10, 1939 2,927,428 Sala Mar. 8, 1960

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