US1727948A - Feed-water system - Google Patents

Description

Sept; 10, 1929. A. STUBBS FEED WATER SYSTEM Filed Dec. 17, 1924 INVENTOR filbert Stubhs WITNESS ATTORNEY Patented Sept. 10, 1929.

UNITED STATES PATENTHOFFVICEQYI,

ALBERT STUBBS, or WINSFOBD, ENGLAND, AssIeNon To wris'rinenotrsn sesam & MANUFACTURING COMPANY, A. CORPORATION or PENNSYLVANIA.

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Application filed December 17, 1924; Serial No. 756,480, and in- Great Britain February 1, 1924.

This invention relates to feed water systems tor condensing steam plant, particular-- ly to that type of system wherein differences between the supply of feed Water by the condenser extraction pump and the demands made upon such supply by the boiler feed pump are compensated by variations of water level in a stand pipe and surge tank connect ed wlth the system between the delivery oi the condenser extraction pump and the sucti on of the ooiler feed pump. a

In accordance with the present invention, sul: '-atn1ospl1er1c pressure is maintained in the surge tank and a second surtre tank may i be provided and connected with the first tank either directly or through the circulatory system, the arrangement when a second tank is provided being such that normal fluctuations are compensated b variations in water tank may conveniently be maintained at subatmospheric pressure by connecting it to the vacuum s ace of the condenser whereas the 0 1 i I pressure 1n the second tank mav conveniently be at orabout atmospheric. The first tank is sealed to enable asub-atmosphericpressure to be maintained therein and the second tank be partially sealed against atmospheric contamination in any suitable manner, as for instance by means of a float. The connection between the first tank and the feed water sys-- tom-may be made either before or after any feed water heaters which may be incorporated in the system so that the temperature 1 p p sponds to'the inlet'pressure of'the boiler feed of the water in such tank may be equal to or greater than that corresponding with the absolute pressure in the condenser.

Several forms of the invention are illustrated by way of example in the accompanying drawings each figure of which is a, diagrammatic representation of suihcient of the feed water system of a condensing steam" connecting the surge tank 5"with the delivery, pipe 4, and 7 the boiler feed-pump, all substantiallv inaccordance with known practice.

In accordance with the invention the upper portion of the surge tank '5 is connected with the vacuum space of the condenser 1 bylmeans of a pipe 8, asecond surge tank 9 is connected with the deliverypipe 4: by means either ota, single stand pipe 10, as in' Figs; 1 and 4,0r of two stand pipes 10 and 11, as in Figs. 2 and 3, and a non-return valve 121s inserted in the delivery pipe 4: between'thepump' 2 andthe stand pipe 6.

In the system illustratednby Fig." 1* the surge tank 5 isconne cted with the surge tank 9 by an overflow pipe 13 and aw'non-return valve 14 is insertedin-the stand :pipe '10. To insure that the diiterence' of pressure which exists in the tanks does not cause water to How from the tank 9 into the tank5'the highest point of the pipe 13 is raised at least34 feet above the normal water level in the tank 9 and to obviate the possibility 'ofwater "flowing from the tank 5 to the condenser 1 the pipe 8' is connected with the tank 5 atahigher level than the connection between the pipe 13 and thetank 5 and the highest'point o f the pipe 8 is located above thehighest point of the With this arrangement, undernormal con" dition'sot operation, thewater level in the tank 5 fluctuates about a mean position in compensation of normal fluctuations of sup plv and demand in the ciroulatory system.i Under such-conditions, the ,discharge'prcs sure of the extraction pump 2, which corre pump 7, is greaterthan thestatic pressure of the water contained in the second surge tank 9 and. hence the check valve 14 is retained '90 ing substantially filled,the excess overflows through the pipe 13 into the second surge tank 9, whereby it is retained in the system. As power; plants have heretofore been arranged, this excess would be lost from the system but by my novel'arr'angement of'employing two surgetanks, this excess is conserved. As the surge tank is arranged a distance above the second surge tanksomewhat in excess of thirty-four feet, there is no danger of the water in the second surge tank 9 being drawn into the surge tank 5 by the su'b-atmospheric pressure prevailing therein. Furthermore, as the overflow pipe 13 enters the surge tank 5 a distance somewhat below the vent connection 8, the excess water will escape through the overflow andnot through thevent pipe.

' secondsurge tank 9 to compensate for the de When the amount'of ,waterdischarged by :the extraction pump 2 is considerably less than the amount required by the boiler feed pump 7, then the surge. tank '5 temporarily compensates for this deficiency until such time as the pressure the pipe 4 becomes "less than the static pressure of the water in the Second surge tank 9 whereupon the check valve 14 is opened to perm-it the Water in the ficien'cy.

It is apparent from the foregoing description, that a'feed Water system so arranged possesses considerable merit over those systems heretofore employed because, the surge tank 5, which takes care of all normal fluctuations in the demands of'the system, is not vented to the atmosphere nor'is its overflow connec'-' tion connected to some point outside the system." On the otherfhand, this tank is so arranged that all vapor and all overflow .con-

densate are retained while the entraining of air in thecondensate is avoided. In .addi-' tion, the system is so flexible that even though an abnormal fluctuation should take place, the second surge tank immediately acts to compensate for such abnormal changes. In this way, the boiler feed pump is always supplied with the required amount of feed water and the system 'op'erates with an extremely high 'thermo dynamic efficiency.

In the system illustrated by Fig. 2 the tanks 5 and 9 are locatedat substantially the same level an'dthe pipe 8 is intheform of an invented U bend the highestpoint of which is approximately .34 see: above the maximum water level in the tank'a. A hon-return valve 14, similar to that employed in the system illustrated by Fig. 1 but adapted to operate in the opposite direction, is inserted in the pipe 10 and a valve controlled by a float, 15, in the tank 5 is inserted in the pipe 11.

WVith this arrangement normal fluctuations in supply and demand are compensated as before while considerable excess of supply ed from the tank 5 until the latter is completely or nearly empty when the float controlled valve 15 will open and the supply will then beiaugmented from the tank 9.

The general arrangement and operation of the system illustrated by Fig. 3 is simlar to that illustrated by Fig. 2 except that the pipe 8 is of any convenient formation and a valve 16 which is-either controlled by the float 16' in the tank 5 and adapted to be closed'when the latter is full, or this valve may be of the type adapted to pass gases whilst closing against liquids is inserted therein.

, In the system illustrated by Fig. 4 the tank 9 is located at a somewhat higher level than the tank 5 and is connected with the latter by a pipe 13. A valve 16 similar to that describedwith reference to Fig. 3 is inserted in the pipeS, a non-return valve 17 is inserted in the pipe 13 preventing the 1passage of liquid from the tank 9'to the tan 5, and a nonreturn valve 14 similar to that employed in the system illustrated by Fig. 1 is inserted in the pipe 10. V I

With this arrangement normal fluctuations in supply and demand are compensated as before while considerable excess of supply over demand will cause the water first to fill the tank 5 and close the valve 16 and then to open the valve 17 and flow into the tank 9. In the event of demand by the feed pump 7 exceeding the supply from the extraction pump 2 the supply will first be augmented from the tank 5 until the latter is completely or nearly empty when the non-return valve 14 will open and the supply will then be augmented from the tank 9. i

In a modification of any of the arrangements herein described two stand pipes may be provided in connection with the tank 5 so that the whole of the condensate may be passed through the latter. This arrange ment is of advantage when a feed water heater is placed between the tank 5 and the extraction pump 4 and it is desired to divide the water upon entry into the tank to facilitate further deaeration in thosecases where aeration of the main condensate has taken lace: after leaving the condenser, for example owing to air leakage at the glands of the extraction pump.

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 modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. In a feed water system, thecombination of a condenser, a pump for receiving condensate from the condenser, a second pump arranged to receive the condensate discharged from the first pump and to discharge said condensate to the system, and two surge tanks communicating with the inlet of the second pump, one of said surge tanks being arranged to compensate for normal fluctuations in the demands of the system and the other surge tank being arranged to compensate for abnormal fiuct-uations in the demands of the system.

2. In a power system, the combination of a condenser, a pump for removing condensate from the condenser, a second pump for receiving the condensate discharged from the first pump and for discharging said condensate to the system, two surge tanks communicating with the inlet of the second pump, the first of said surge tanks having a sub-atmospheric pressure prevailing therein and being arranged to compensate for normal fluctuations in the demands of the system and the second surge tank having atmospheric pressure prevailing therein and arranged to compensate for abnormal fluctuations in the demands of the system.

3. In a power system, the combination of a condenser, a pump for removing condensate from the condenser, a second pump forreceiving the condensate discharged from the first pump and for discharging said condensate to the system, and two surge tanks communicating with the inlet of the second pump, the first of said surge tanks being vented to the condenser and arranged to compensate for normal fluctuations in the demands of the system and the second surge tank being arranged to receive condensate overflowing from the first tank and to compensate for abnormal fluctuations in the demands of the system.

4. In a feed water system, the combination of a condenser, a pump for removing condensate from the condenser, a second pump for receiving the condensate discharged from the first pump and for discharging said condensate to the system, a surge tank freely communicating with the inlet of the second pump, a second surge tank communicating with the inlet of the second pump, and means provided between the second surge tank and the inlet of the second pump to permitthe condensate to fiowonly in a direction from the second surge tank to the inlet ofthe sec ondpump' j 5 The-combination with a feed water system comprising fluid-translating devices arranged in'series and a surge tank connected to said system between said fluid-translating device's, ofmeans for maintaining a sub-atmospheric pressure in said tank, a second tank, means for passing a liquid only'from the; first to said second tank, and means for supplying liquid to said system from said second tank when the supply of liquid in said first 'tank is inadequate for this purpose.

6. The combination with a feed water system comprising fluid-translating devices ar ranged in'series and a surge tank connected to said system between said fluid translating devices, ofmeans for maintaining a. sub-atmospheric pressure in said tank, a second tank, means for passinga liquid only from the firstto said second tank, and pressureresponsive means for supplying liquid to said system'from said second tank when the supply of liquid in said first tankis inadequate forthispurpose. 3

7 The combination with a feed watersystem comprising fluid-translating devices'arrangedin series,'a surge tank connected to said system between said fiuid translating devices, and means for maintaining a sub'-atmospheric pressurein said tank, of a second tank connected to said system between said fluid-translating devices, means forsupply-' ing liquid to said system from said second tank when thesupply of liquid in the first tank is inadequate, and means forpassing liquid to said second tank when the delivery of the firstfluid translating device exceeds the requirements of the next fluid-translating de vice andthe capacity of said first surge tank.

' 8. A feed water system comprising fluidtranslating devices arranged in series, a plurality of tanks connected to said system between said fluid-translating devices, means for producing deaeration in one of said tanks, and means for passing liquid to another of said tanks when the supply ofliquid exceeds the capacity of said one of said tanks.

9. A feed water system comprising fluidtranslating devices arranged in series, a plurality of tanks connected to said system between said fiuid-translating devices, means for producing deaeration in one of said tanks, and means for passing liquid from another of said tanks to said system when the requirements of the system exceed the capacity of said one of said tanks.

10. A feed water system comprising fluidtranslating devices arranged in series, a plurality of tanks connected to said system between said fiuid-translating devices, means for producing deaeration in one of said tanks, and means for passing liquid to or from anotherof said tanks. accordingly as thesupply of liquid or the requirements for liquid exceed the capacity of said one of said tanks. 11. The combination with a condenser and 5 a feed water system for utilizing condensate as feed water, wherein the system has fluidtranslating devices arranged in series, of a plurality of tanks connected to said system between said fluid-translating devices, one of said tanks being closed, a connection from said one of said tanks to the condenser for exposingthe surface oiliquid in said one tank to condenser pressure, means formaintaining liquid in another of said tanks at substantially atmospheric pressure, and means for passing liquid to or from said another of said tanks accordingly as the supply of liquid or. as the requirements for liquid'exceed the capacity of said one of said tanks. I v 12. A feed water system comprising fluidtranslating devices arranged in series, a plurality of tanks connected to said system between said fluid-translating devices, means for producing deaeration in one of said tanks, and pressure-responsive means for passing liquid to another of said tanks when the supply of liquid exceeds the capacity! of said one of said tanks. p 1 v 13. A feed-water heating system comprising fluid translating devices arranged in series, a non-return valve interposed in said. system on the discharge side of the firstfluid translating device, a surge tank connected to said system between-the non-return valve and thesecond fluid translating device, means for maintaining a sub-atmospheric pressure in said surge tank, a second tank, means for pass-- ing'a liquid onlyfrom the first to the second tank, and pressure responsive means for $1.0 supplying liquid to said system from said second tank when the supply of liquid in said first tank is inadequate for this purpose. In testimony whereof, I have hereunto subscribed my name this 13th day of Nov., 1924.

ALBERT sTUBBs.

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