US1930064A - Condensate removal apparatus - Google Patents

Description

Oct. 10, 1933. $HM|DT 1,930,064

CONDENSATE REMOVAL APPARATUS Filed May 3, 1932 WITNESS INVENTOR 6 3 BY HEN/2v FT SCHMIDT. W75. M

A TTURNE Patented Oct. 10, 1933 UNITED STATES 1,930,064 CONDENSATE REMOVAL APPARATUS Henry F. Schmidt, Lansdowne, Pa., assignor to Westinghouse Electric & Manufacturing Company, a corporation of Pennsylvania Application May 3, 1932. Serial No. 608,992

3 Claims.

My invention relates to ejector-type condensate removal and translating apparatus for steam condensers.

It has heretofore been proposed to provide 5 steam operated ejector apparatus for removal of condensate from steam condensers, and, while apparatus of this type is advantageous from the point of view of not having any moving parts and from that of feasible location of such apparatus in inaccessible places, nevertheless, it is subject to the disadvantage that, when the condenser vacuum becomes poor, the ejector may fail because of boiling of the condensate. To overcome this dimculty and to provide more efficient and reliable apparatus, I use water supplied by the boiler feed pump as the motive fluid for the ejector.

' As the boiler feed pump is in operation whenever the power plant is operating, it constitutes a reliable source for ejector motive fluid. As ordinarily designed, the boiler feed pump has excess capacity over that required for supplying the boiler; and such a pump may, therefore, be used also to supply water as motive fluid to the condensate ejector, the water so supplied constituting the sole energy medium for the-ejector, at least for the lower range of loads. For the higher range of loads, the' water-motivated ejector may be assisted by a steam ejector, the 30, latter preferably being under the controlof plant load-responsive means, such as a prime mover governor.

The arrangement having a steam ejector assisting the water ejector for the higher range of loads also has a heat balance advantage. The plant may be provided with a feed water heater which is of a size adequate for heating requirements up to the load at which the steam actuated ejector becomes effective; and, while the in- 40 creased quantity of feed incident to the increased load would ordinarily in itself tend to lower the discharge temperature of the water leaving the feed water heater, yet, this is compensated for by heat of the motive steam added to the Water by the steam ejector. Hence, with this arrangement of apparatus, the steam actuated ejector makes possible a wide load range with feed water heating apparatus of minimum size or capacity.

A condensate ejector utilizing boiler feed water or such water and steam is particularly advantageous in marine installations. On board ship, it is desirable to use power plant apparatus which is economical in its requirements for space; and

a condensate ejector is peculiarly suitable not only on account of compactness but also on account of the feasibility of locating it or parts thereof in inaccessible places. The power requirements for marine propulsion increase substantially as the cube of the speed. Therefore,

in a marine installation, the ejector may be so 60 arranged that, at low speeds and loads, only the boiler feed water motivated ejector is in operation, while, at higher loads and speeds, both the water motivated ejector and the steam motivated ejector are in operation; and, speed responsive 55 means may, therefore, be used in connection with the prime mover to control the admission of steam to the steam actuated ejector at higher loads and speeds. As already pointed out, this arrangement of condensate removal apparatus makes it possible to secure efficient operation with feed water heating apparatus of minimum size, the feed water heating apparatus being of adequate size to heat feed water for low loads and speeds, and the deficiencies thereof at higher loads and speeds being substantially compensated for by the heat of motive steam added to the feed water by the steam actuated ejector.

The discharge from the condenser air ejector is also preferably used as motive fluid in an ejector to assist the water ejector in removing and translating the condensate.

It is, therefore, an object of my invention to provide an ejector for removing and translating condensate from a steam condenser, the ejector being motivated by Water supplied by a boiler feed pump.

A further object of my invention is to provide a condensate ejector motivated by water supplied by a boiler feed pump and assisted, at least for 0 the higher load range, by a steam actuated ejector.

A further object of my invention is to provide ejector apparatus for a steam condenser includ ing an ejector motivated by water supplied by a boiler feed pump together with an ejector motivated by steam, the latter ejector assisting the Water-actuatedejector and being under the control of load responsive means of the plant so that it is effective for the higher load range.

A further object of my invention is to provide a power plant peculiarly suitable for marine propulsion in that ejector apparatus is used to translate condensate, boiler feed water being used at low loads and speeds as the motive medium and steam being used as additional motive medium at higher loads and speeds, whereby not only is the'installation compact but also it operates advantageouslyfrom the point of view of feed j of the speed of the turbine.

water heating over a wide range of loads and speeds.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawing and forming a part of this application, in which:

The single figure is a diagrammatic view showing a power plant arrangement incorporating my invention.

Referring now to the drawing more in detail, I show a power plant comprising a boiler 10 supplying steam to the turbine 11 and to auxiliary apparatus, such as the turbine 12 for the boiler feed pump, at 13, the turbine 11 exhausting to the condenser 14.

Condensate is withdrawn from the condenser hot-well 15 by ejector apparatus, at 16, and translated through a suitable conduit 17 to the feed tank 18. The ejector apparatus, at 16, includes an ejector 20 motivated by water supplied through the passage 21 from the boiler feed pump, at 13. The conduit17 is provided with a check valve 19 to prevent back fiow toward the ejector apparatus.

As shown, the boiler feed pump 13 preferably comprises a plurality of stages 22, 23, and 24, the last supplying water through the conduit 25a to the boiler and the intermediate stage 23 supplying water to the water motivated ejector 20.

The boiler feed pump not only is in operation whenever the plant is in operation, but ordinarily has excess capacity over the requirements for feeding water to the boiler. This excess capacity may be utilized, at least for a low range of loads,

for furnishing water as motive fluid to an ejector for removing and translating condensate from the condenser, and accordingly, I show a boiler feed pump, at 13, connected to the ejector 20 j and serving this purpose. For the higher range of loads, for example, above one-half maximum load, it is desirable to assist the water actuated ejector 20 in some way on account of the increasing quantity of condensate to be removed '1 and translated. Therefore, I show a steam actuated ejector 25 arranged in tandem or in series with respect to the. ejector 20, and capable, when steam is admitted thereto, of assisting the water actuated ejector.

Motive steam is supplied to the ejector '25 through a conduit 26 having a valve 27 arranged therein, the valve 27 being controlled by the turbine governor 30 so that the valve is closed for loads below an intermediate load and is open for loads thereabove.

of the speed. Therefore, it is possible to provide means for developing pressure dependent upon the speed of the prime mover for controlling the admission of steam to the steam actuated ejector. To this end, in the drawing, I show the turbine 11 provided with an impeller 30a which develops oil pressure varying substantially as the square A pressure line 31 has its inlet end connected peripherally of the impeller housing and it communicates with the lower portion of the cylinder 32 below the piston 33, the latter being connected to the valve 27. A spring 34 is arranged above the piston 33 and it is effective to move the valve 27 to closed position when the force thereof is greater than oil pressure force acting below the piston. Oil escaping by the piston 33 is returned to the impeller housing by the return line 32a. It will,

therefore, be apparent that, for the low range of loads and speeds, when the force of the oil pressure below the piston 33 is less than that of the spring 34 the valve 27 will be closed. On the other hand, for a higher range of loads and speeds, the force of the oil pressure will be greater, with the result that the valve 27 will open to supply steam as motive fluid to the steam actuated ejector 25. This arrangement is advantageous from the point of view of heat balance, as the feed water heater 38 may be of a size sufficient to heat feed water at the low range of speeds and loads and with the wateractuated ejector 20 in operation; and, at the higher range of loads and speeds, deficient capacity of the feed water heater is substantially compensated for by the heat of motive steam supplied to the ejector.

As a steam condenser must be provided with air removal means, I show the condenser 14 providedwith a suitable air ejector 35 and the discharge from the ejector is supplied through the passage 36 to serve as motive fluid for the intermediate ejector 37 arranged between the water ejector 20 and the ejector 25. By having the air ejector serve as a source of motive fluid for the intermediate ejector; not only is there some assistance in securing the removal and translation of condensate, but the heat of the exhaust or discharge of the ejector 35 is recovered in the condensate.

A feed water heater 33 is arranged in the water line between the feed pump, at 13, and the boiler 10. Heating medium, for example steam, is supplied to the feed water heater 38 by pipe 38a, the latter being connected to any suitable source ofsteam supply, for example, the exhaust of auxiliary apparatus or, if desired, the heating steam may be bled from an intermediate stage of the main turbine. This heater is preferably made of a size sufiicient to heat the feed water to the desired degree for the range of loads for which the water actuated ejector 20 is itself sufiicient to secure the removal and translation of condensate; for loads in excess of this lower range, the feed water heater would be insufficient in itself to heat the feed water to the required degree but for the cooperation of the steam actuated ejector in this connection, it being apparent that the heat of motive steam supplied to the ejector 25, as well as to the ejector 37, is effective to heat the condensate, whereby the deficiency of the feed water heater at the higher range of loads is to a large extent compensated for.

From the foregoing, it will be apparent that I have provided condensate removal and translating apparatus which is particularly advantageous for marine installations. Not only is the ejector apparatus comprised by fixed parts and, therefore, feasibly located in inaccessible places, but the ejector apparatus is efficient and reliable in operation. As the principal motive agent for the ejector apparatus is water supplied by the water feed pump, there is no likelihood of failure thereof on account of boiling of the condensate when the vacuum is reduced. Furthermore, as a boiler feed pump ordinarily has excess capacity, it may be used to provide the sole motive means for the ejector apparatus, at least for the lower load range, the ejector being assisted, for the higher load range, by a steam actuated ejector. Heat balance of the organization and economy of feed water heating apparatus is secured by providing a feed water heater which is adequate for the feed water supplied to the, boiler for the lower range of loads, but which, in itself, would be inadequate for this purpose for the higher range of loads, this deficiency in feed water heating apparatus being compensated for by the heat added to the condensate by motive steam of the steam actuated ejector. Furthermore, the steam actuated ejector is subject to a load responsive characteristic of the turbine 11, the steam being admitted to the ejector 25 for the higher range of loads and being cut off for the lower range of loads. Any suitable source of steam may be utilized to supply motive fluid to the ejector 35 and to the compensator ejector 25, for example, I show an auxiliary exhaust line 40 serving this purpose.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, Without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed there upon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. In a steam power plant including a prime mover exhausting to a condenser, the prime mover having load-responsive means, and a boiler feed pump, means for removing condensate from the condenser and for translating such condensate including an ejector motivated by water supplied from the boiler feed pump, a steam actuated ejector for assisting the water ejector when the plant load exceeds a predetermined amount, and means responsive to the prime mover load-responsive means to control the supply of steam to the steam-actuated ejector.

2. In a power plant; the combination with a boiler, a boiler feed pump, a feed water heater and a prime mover exhausting to a condenser; means for returning condensate from the condenser through the feed water heater to the boiler including an ejector motivated by Water received from the boiler feed pump, a steamactuated ejector effective in series with the Water-actuated ejector, and means responsive to a predetermined prime mover load to render the steam-actuated ejector effective, whereby the motive steam of the steam-actuated ejector is efiective to assist the feed water heater at the higher load range.

3. In a marine power plant; the combination with a boiler, a boiler feed pump, a feed water heater, and a prime mover exhausting to a condenser; means for returning condensate from the condenser through the feed water heater to the boiler including an ejector motivated by water received from the boiler feed pump, a steam-actuated ejector eifective in series with the Water-actuated ejector, and means responsive to a predetermined prime mover speed to render the steam-actuated ejector effective, whereby the motive steam of the steam-actuated ejector is effective to assist the feed water heater at the higher range of speeds and loads.

HENRY F. SCHMIDT.

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