US1535440A - Feed-water system - Google Patents

Description

'Api il 28, 1925. 1,535,440 C. U. SAVOYE FEED WATER SYSTEM Filed Feb. 26, 1923 m g INVENTOR.

Patented Apr. 28, 1925.

UNITED STATES PA E T OFFICE.

CHARLES ULYSSE SAVOYE, OF HACKENSAGK,NEW JERSEY, ASSIGNOR TO THE BAB COCK & WILCOX GOMPANY, OF BAYONNE; NEW JERSEY, A CORPORATION OF NEW JERSEY.

rnnn wa'rna SYSTEM.

Application filed February 26, 1923. Serial No. 621,492.

To all whom it may concern:

Be it known that I, CHARLES ULYssn Savors, a citizen of the United States, and a resident of Hackensack, in the county of 5 Bergen and State of New. Jersey, have mvented certain new and useful Improvements in Feed-Water Systems, of which the following is a specification.

My present invention relates to feed water systems for steam poweriplants lIl whlch the condensate is returned to theboiler.

My invention will be best understoodfrom the accompanying drawing; inTwhichI have shown more or less diagrammatically, an illustrative embodiment thereof. In said drawing, steam from a boiler 10 is led through pipe 11 to a turbine or other primemover 12, which, in the case Sl10W11,d11VES an electric generator 14. Exhaust steam from turbine 12 passes into condenser 15 and the condensate therefrom is forced from hot-well 16 and pipe 18, into one side of a feed tank'QO, bypump 19, driven by motor 21. From feedmtank 20, the COIlClGIlSELtGHS returned to boiler 10 through pipe 30. and

boiler feed pump32. l

-The feed water is drawn from tank 20 by pump 52througlrpipe 51 into an economizer 50 from whichthe heated water flows back into the other side of tank 20, the two parts of the tank being determined by a partition 55 over which there maybe a How from one side to the other, as the differential pressure between the two sides increases. A relief valve 60, in the form of a mercury trap, is providedto prevent damage incase anyof the regulating devices hereinafter described, fails to operate. It will be ObVlOUS that the economizer 50 may be dispensed with and the water from tank 20 supplied directly to the boiler 10, in which case, the partition will not be necessary. v i

For the purpose of supplying makeup water to the system, I provide a clear water reservoir 40, and water therefrom flows through pipe 42, mercury-operated U-tube valve-44L and pipe 45, into hot-well 16; The valve 44 will be described more in detail hereinafter.

Preferably, the condensate pump 19 is of sufficient capacity to handle themaximum requirements of feed water when run at a givenconstant speed;

44, as shown.

In normal operation, where the condensate 18 just equal to the demand of the feedpump 32, the valve 44 will remain closed, and hence theconnectioniof the hot-well 16 to the clear water reservoir 40 will be cut off. That is to say, the water from the condensate pump19 throughpipe 18 will flow through feed tank 20 through economizer' 50, back to feed tank 20 and thence to the boiler. For reasons which will later be apparent, I advantageously make the feed water tank 20 closed against the atmosphere. Normally the-tank 20 is maintained under a positive gauge pressure equal to any convenient value, say, five pounds above atmosphere.

I will now describe in detail Valvedl and the control means therefor. A conduit (it) is provided from feed tank'QOto a chamber 63. ,A conduit Mleads from the lowermost portion 65 of the U-tube 4lto the lowermost portion 66 of chamber 63. An enlarged conduit 67, having a vertical portion 68 above :the bottom 66 of chamber 63, extends to the same height as the upper portion of valve The top of vertical conduit 68 is connected by a pipe with clear water reservoir 40. V r

Sufiicient mercury 70'is placedin the sys tem, comprising 'chamberQTO, valve 44 and pipe 67, so that upon normal operation of the power plant, i. e., when the amount of condensate equals the demand ofthe boiler feed pump, the mercury will extend up in pipes 64 and 65 and into the legs of Ll-tube valve 44: to act as a seal'to prevent water flowing fromclear water reservoir l0 to hot well. 16. It will be apparent that the height of the mercury columns in the legsof the U- tube 14: will be conditioned upon several factors, as, for example, the difference in height of tank 20 and clear water reservoir 40,the amount of vacuum maintained over the water in the reservoir 40, the pressure in feed tank 20, etc. It is also apparentthat the height of the mercury in the vertical conduit 68 will be equal to that in the right hand leg of U-tube at.

In case the supply of condensed steam does not equalv the demand of feed pump 32, then the pressure in the closed feed tank 20 will fall, releasing some of the pressure on the surface of the'mercury 70in chamber 62-3. In case the diminution of pressure be 3 will rise to such a height as to drain the mercury from the legs of U-tube 4A, thereby permitting flow of water from clear water reservoir 40, through conduit 42, U-tube 44 and pipe d5, into hot-well 1G, whence it is pumped to feed tank 20 by means of condensate pump 21. The increased flow into tank 20 will raise the water level therein and thus build up the pressure therein. This pressure will act upon the surface of the mercury in chamber T0 through the medium of the water in pipe 60 and force it back into the legs of lJ-tube at (as well as pipe 08), thereby cutting oil the flow of water from reservoir 4:0 into hot-well 16.

Conversely, when tl e supply of condensate is greater than the demand or": boiler teed pump 32, the increase 01"- fluid pressure upon the level of the mercury in chamber 63 by reason of the rise of the water level in tank 20, will force the mercury through pipe 6-1 and into the legs of U-tube H, and will con tinue to force mercury out of chamber 63 until the mercury in pipes 67 and 68 have been drained. This will permitflow of water from feed tank 20 back into clear water reservoir 40, through pipe 60, tank 63 and pipes 67, G8 and 60, and this flow will continue until the pressure in feed tank 20 allows enough mercury to flow back from lJ-tnbe ll until the end of pipe 67 in chamber 68 is again covered, when flow in pipe 60 is cut oil.

It will thus be seen that I have provided a control means for the valve 914 in the sup ply conduit, comprising the portions 42, 45 and 18, which will operate to open said valve when the pressure in the feed tank falls below a predetermined value, and to open the valve in the conduit between the feed tank 20 and the reservoir 40 when the pressure in teed tank 20 builds up to a predetermined point, and to close both valves 14 and (33 when the pressure in the feed tank is between said valves.

It is a matter oi importance that the amount ot air entering'the system, by being dissolved in the water ted thereto, be kept as low as possible. It will be. seen that the water which is condensed in condenser 15 and returned to boiler 10, utter passing through teed tank 20, is maintained in a closed system and that no opportunity is attorded tor the water to come into contact with air. Any air which becomes dissolved in the condensate will be reduced to a minimum by being subjected to the vacuum in condenser 15, and removed through exhaust conduit 90 by means of condenser air pump 91. In order that the water entering the s tem from clear water reservoir 40 may likewise be treed of dissolved air, I provide a conduit 80 connecting the vacuum space of condenser 15 to the space above the water reat enough, then the mercury in chamber level in the reservoir 40, whereby the water therein is at all times subjected to substantially the condenser vacuum.

For supplying reservoir 40 with water, I provide a valve, denoted generally by re1- erence numeral 90, and this valve may conveniently be of a type operated by mercury, as will now be described. i i hen the valve is in closed position, the flow of water in supply conduit 102 is prevented by the mercury partly filling a vertical pipe 92 about its point of connection to pipe 102. The top of pipe 92 is connected by pipe 93 with the air space in tank 40. The bottom of pipe 92 is connected to the bottom of a vessel 95 and a plunger 96 floats in the mercury filling this vessel. Plunger 96 is provided at its top with a chamber 97 connected with the water and the air spaces of reservoir 40 by flexible conduits 100, 101, respectively. The parts are arranged so that, when the level in tank 40 is normal, mercury will cover the lower end of pipe 102, because the weight of water in chamber 97 will hold the level oi? the mercury in pipe 92 above that point. When the level of the water in reservoir 40 falls below normal, chamber 97 will be partially drained through flexible conduit 100. The decrease in weight on plunger 96 which is thereby occasioned will cause said plunger to rise, thereby causing a flow of mercury into chamber 95 from conduits 92 and 102, unsealing the end of pipe 102 and allowing water to flow through conduits 91, 92 and 93 into reservoir 40. As the water level in reservoir 40 rises, plunger 96 will sink in the mercury and the mercury displaced will again seal the lower end of pipe 102 to cut oil the flow 0t water from th conduit 102.

Prelierably, I arrange the normal water level in tank 20 so that the pressure above the water is greater than an atmosphere. This prevents the tendency to term a partial vacuum when the level falls, so that/at all tin'ies, a positive pressure is applied to the system, and the valves are operated by dil'- l'erences in this positive pressure.

ll; will be seen that l have provided a sim ple and eflicient feed water system in which fluctuations of water supplied by the condenser are automatically taken care 01 with out the use of the usual surge tank, and in which the water supplied to the boiler is maintained practically aii tree. It will also be noted that my control valves are operated by changes of pressures in the feed tank rather than by changes in water levels. It will also be understood that the arrangement described is merely illustrative and that the embodiment of my invention may be varied within wide limits.

I claim 1. In a feed water system, a steam boiler, a closed tank arranged to receive the condensat-e from exhaust steam, connections between said tank and the boiler, a clear water reservoir, a normally closed connection between the reservoir and the tank, and means, controlled by the pressure in said closed tank, to open the connection between the tank and the reservoir when the pressure in this tank exceeds a predetermined amount.

2. In a feed water system, a steam boiler, a closed tank arranged to receive the condensate from exhaust steam, connections be tween said tank and the boiler, a clear water reservoir, a normally closed connection between the reservoir and the condensate supply, and means, controlled by the pressure in said closed tank, to open said connection when the pressure in said tank is less than a predetermined amount.

3. In a feed water system, a steam boiler, a closed tank arranged to receive the condensate from exhaust steam, connections between said tank and the boiler, a clear water reservoir, connections between said reservoir and the condensate supply and between said reservoir and said closed tank, and means, controlled by the pressure in said closed tank, to close both said connections when the pressure in said tank is within predetermined limits, and to open the connection between the tank and the reservoir when the pressure exceeds such limit and to open the connection between the reservoir and the condensate supply when the pressure is less than such limits.

4;. In a feed water system, a steam boiler, a closed tank, a condensate well, a constant speed pump to force water from the well to the closed tank, connections between the tank and the boiler, a clear water reservoir, a normally closed connection between the reservoir and the tank, and means, controlled by the pressure in the tank, to open the connection between the reservoir and the tank when the supply of condensate to the tank exceeds the supply from the tank to the boiler.

55. In a teed water system, a steam boiler, a closed tank, a condensate well, a constant speed pump to :torce water from the well to the closed tank, connections between the tank and the boiler, a clear water reservoir, a normally closed connection between the reservoir and the condensate well, and

means, controlled by the pressure in the tank, to open said connection when the supply to the boiler exceeds the supply of condensate to the well.

6. In a feed water system, a steam boiler, a closed condensate well arranged to receive condensed steam, a closed tank, connections between the tank and the boiler, a closed clear water reservoir, connections between the tank and the reservoir and between the well and the tank, all of said connections being arranged to maintain the water out of contact with the atmosphere, a constant speed pump to force water from the well to the tank, and a valve, controlled by the pressure in the tank to close the connection between the tank and the reservoir when the supply to the boiler equals or exceeds the supply of condensate to the tank and to open the valve when the supply of condensate to the tank exceeds the supply to the boiler, and a valve, controlled by the pressure in the tank, to close the connection between the reservoir and the well when the supply of condensate to the well equals or exceeds the supply to the boiler and to open the valve when the supply to the boiler exceeds the supply of condensate to the well.

7. In a feed water system for a steam boiler, a condenser, a closed makeup water reservoir and a conduit connecting the space above the water level in the reservoir with the vacuum space of the condenser.

8. In a feed water system for a steam boiler, a condenser, a closed makeup water reservoir, a conduit connecting the space above the water level in the reservoir with the vacuum space of the condenser, and means for feeding water to said reservoir constructed and arranged to maintain an approximately constant level therein.

9. In a feed water system for a steam boiler, a condenser, a closed makeup water reservoir, a conduit connecting the space above the water level in the reservoir with the vacuum space of the condenser, and means for feeding water to said reservoir constructed and arranged to maintain an approximately constant level therein independent of changes in pressure in said reservoir.

CHARLES ULYSSE SAVOYE.

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