US1636361A - Water heating and deaerating - Google Patents

Description

1 2 July 9 7 G. H. GIBSON WATER HEATING AND DEAERATING Filed Nov. 5, 1923 WW ATTORNEY Patented July 19, 1927.

UNITED STATES 1,636,361 PATENT OFFICE.

GEORGE E. GIBSON, OE MONTCLAIR, NEW JERSEY, ASSIGNOR TO COCHRANE CORPORA- TION, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF I'ENNSYLVANIA.

WATER HEATING Application filed November 5, 1928.

The general object of my present invention is to provide improved water heating and deaerating apparatus. More specifically the object of my present invention is'to provide simple and effective means for utilizing steam bled from an intermediate stage of a steam turbine in heating and deaerating boiler feed water.

In carrying out my invention I employ a heating and deaerating chamber, through which I pass the water to be heated and deaerated in such manner that a vapor space is maintained in the upper portion of the chamher, while the lower portion serves as awater storage and scrubbing space, and I supply heat to this chamber partly by the direct admission of steam to the chamber and artly by means of a steam heater located within and comprising a steam space separate from and out of communication with the water and. vapor space of the chamber. This steam heater, which advantageously comprises a bank of tubes located wholly or partly below the normal water level in the heating and deaerating -chamber, receives the steam bled from the turbine for the purpose, and supplies heat to the water in such fashion as to evaporate a portion of the water and to exert a scrubbing effect on the water not evaporated which facilitates the rapid and complete liberation of the air contained in the water entering the chamber. The steam formed by the evaporative effect of the steam heater is condensed in the vapor space of the deaerating chamber by the incoming water which is thereby heated approximately to its delivery temperature as it falls through the vapor space of the chamber.

By supplying heat to the deaerating chamber through a steam heater having a steam space separate from the deaerating chamber, I am enabled to use steam at a pressure independent of and advantageously somewhat higher than the vapor pressure and water temperature respectively, in the deaerating chamber. Furthermore, heat may thus be supplied to the deaerating chamber below the normal water level therein, which is desirable as hereinafter explained, without an injurious reaction'on the turbine as a resu t of fluctuations in the temperature and pressure in the deaerating chamber, as might happen if the steam bled from the turbine were piped directly into the deaerating chamber at or below v normal a r le el there n. In

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Serial No. 872,906.

imizing the risk-of the water being sucked into the turbine as a result of pressure fluc- Euations in the heating and deaerating cham- The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects attained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of my invention.

Of the drawings Fig. 1 is a diagrammatic representation of a water heating and deaerating system;

Fig. 2 is a plan view of the heating and deaerating chamber proper;

Fig. 3 is an elevation of the heating and deaerating chamber with parts broken away and in section; and

Fig. 4 is a section on the line 44 of Fig. 3.

In the water heating and deaerating system shown diagrammatically in Fig. 1, A represents a steam turbine having a steam inlet A and an exhaust steam outlet A The latter is connected to the steam inlet of a condenser B from the hotwell of which a pump C draws water of condensation through a pipe B. The pump C discharges the condensate through the pipes D and D to a feed water heating and deaerating chamber E. Preferably an air cooler G is interposed between the pipes D and D for utilizing the water passing to the chamber E in cooling the air and condensing the vapor mixed therewith, which passes out of the chamber E and into the cooler G through the vapor pipe G. Gr represents a discharge connection through which air and water of con densation is discharged from the air cooler G. The up er ort1on of the heating and deaerating c am r 1*} SW$ 3 an ear and vapor space through which the water issurfaceheaterKis provided in the pipeline assed in finely divided or broken streams into the lower water holding space of the chamber.

Heat is supplied to the chamber E by passing steam, bled from the intermediate stage of the turbine A, through thesteam outlet A into tubes e located withln the chamber E wholly or partly below the normal water level therein. F represents a trap for discharging water of condensation forming in the pipes e to a sump or other suitable receiver for this water. Advantageously the purified water is passed from the device E to a water storage chamber I through the pipe E, which opens into the deaerator chamber at a level slightly above the tubes e, and determines the normal height of water level in the chamber E. A fioat HB located at a higher level than the pipe E opens a valved overflow outlet connection E to discharge water to waste from the chamber E if the water level therein becomes unduly high for any reason. The water storage tank I supplies a boiler feed pump J. Advantageously a float HA in the storage tank I controls a valve da 111 a make-up water supply line DA. Asshown the make-up supply DA connects with the pipe D adjacent the outlet from the hotwell pump C, and in such case a check valve X is advantageously provided between the hotwell pump outlet and its connectlon to the make-up supply line DA. I represents a vapor equalizing connection between the upper portion of the storage tank I and the chamber E. Heat is also supplied to the chamber E by passing steam directly into the latter through the turbine bleeder outlet A which opens from a stage of the turbine in which the pressure is somewhat lower than in the stage from which the bleeder outlet A opens. For safety a suitable check valve R is provided in the bleeder outlet connection A, although the bleeder outlet A is connected to the chamber E well above the normal water level therein.

The check valve R serves to prevent an objectionable, and sometimes dangerous back rush of steam into the turbine which would otherwise occur when the turbine load goes off and the pressure in the stage of the turbine from which the connection A leads, falls below the pressure of saturated steam at the temperature of the water in the chamber E. When this occurs, but for the check valve R, a portion of the water in the chamber E would flash into steam and pass through the bleeder connection A back into the turbine, and the amount of water in the chamber E is normally sufliciently large to produce a quantity of steam under such circumstances large enough to be seriously detrimental.

Advantageously, in many cases, a primary D to receive steam from a stage of the turbine A through the stem outlet A at a pressure lower than that of the steam supplied through the blceder outlet A. The steam supplied to the heater K may be at a temperature appreciably below that to which the water is heated in the chamber E, and forms an economical source of heat for iving the water some of the heat which the latter must receive to raise it to its final delivery temperature. Cutoff valves P are provided in the turbine outlets A A and A. If the plant comprises coolers such as air and oil coolers L, these may advantageously be connected in the pipe line D so that the water passing to the deaerating chamber may act as the coolin medium in such coolers and absorb heat tierefrom.

The heating and deaerating chamber E may advantageously be of the construction illustrated in Figs. 2, 3, and 4, wherein the chamber E is shown as a horizontally elongated tank with the upper portion of its vapor space divided into two end compartments E and a central compartment. Each compartment E is open at its lower end to the body portion of the tank interior above the maximum normal water level therein. The top and outer end walls of each" compartment E are formed bycorresponding portions of the outer wall of the tankE, and the inner end wall of each compartment E is formed by a corresponding partition E". The turbine bleeder outlet A is connected to the chamber E, as shown, so that it opens to the space between the partitions E at or near the top of said space. A set of spreader bafllcs or trays E is arranged in each compartment E and over these the water supplied by the piping D passes in film like and broken streams. discharged onto the trays E from suitable water distributing boxes M. Advantageously the water boxes M may contain air cooling spaces through which the air and vapor withdrawn from the interior of the chamber E proper passes to the air piping G leading to the air cooler G. I have not thought it necessary to illustrate or describe the construction of the boxes M in detail herein however, as the specific construction of these boxes forms no part of the present invention, and such boxes are fully disclosed in my copending application, Serial '0. 645,934, filed June 16, 1923. The compartments E are connected by a pressure equalizingpi e E As shown in Figs. 2, 3, and 4, the steam pipes e are arranged in two sets extending longitudinally of the chamber E. The tubes 6 in each set are connected .at their inner ends to a steam box e to which the turbine steam outlet A is connected. Advantageously the pipes e are slightly inclined from The water is the horizontal downwardly from the steam box 0 to the headers e at the ends of the tank E, to which the corresponding ends of the pipes e are connected. A water of condensation trap F is connected to each of the headers 6 Advantageously the air cooler G is a two stage cooler of known type comprising two air cooling and condensing chambers Gr and G separated by a. horizontal partition G, with some of the tubes through which the water flows from the pipe D to the pipe D passing through the compartment G and the remainder passing through the compartment G". A steam ejector -draws air and uncondensed vapor mixed with it, from the chamber G and discharges it into the chamber G. The air discharge connection G opens to the atmosphere from the compartment Gr and may also serve to discharge water of condensation formed in the compartment G. Water of condensation formed in the compartment G is advantageously returned to the chamber E through the drain connection E". The -air' cooler G is in effect a two stage air cooler of which the compartment (1: forms a precooler with the vapor pressure therein the same as in the tank E, while the compartment G is an after cooler in which a pressure equal to that of the atmosphere is maintained.

The special tank construction E with the spreader trays arranged in the compartments E as illustrated, isadesirable one as it provides a substantial water storage and scrubbing space in the lower portion of the tank with a relatively large top surface from which air and vapor may escape, and at the same time it provides for a desirably close contact between the water flowing down over the trays E and the air and steam passing upward to the air and vapor outlet piping G. This tank construction while novel with me is not claimed herein, however, as it is disclosed and claimed in my copending application, Serial No. 645,934. Moreover, the use of this or any other specific tank construction is not essential to the use of the present invention.

In the contemplated use of the apparatus described, the water passing into the tank E at the top is heated practically to its final delivery temperature before it enters the Water pool in the lower portion of the tank by the steam supplied to the chamber E through the bleeder outlet connection A, and

by the steam and air mixture rising from the surface of the body of water held in the lower portion of the chamber, and as the water is thus heated it gives up a large portion of its air content. The air thus liberated mixes with the air in the air and steam 'm'xture rising from the water storage portion of the tank, and passes to the air outlet piping G. The steam in the air steam mixture is largely condensed by contact with the falling water before passing to the outlet piping G'. The temperature to which the water is heated in passing through the apparatus will correspond to the temperature of steam when at the vapor pressure maintained in the upper portion of the chamber i. e. at the temperature of the steam withdrawn from the turbine through the outlet A. The steam in the heater pipes 0 will be at a temperature above that to which the water is heated and in consequence the water passing over those pipes Wlll be subjected to a vigorous boiling action effective to separate from the water all or all but a minute and insignificant residue of the air originally contained in the water. While the air liberated from the water by the boiling due to the hot pipes 6 will ordinarily be small in amount in comparison with the amount liberated from the water as it is heated up in passing through the vapor space of the chamber E, it is the elimination of this final portion of the air content which is most difficult. in ordinary commercial practice. The apparatus thus provides for the energet-ic boiling or scrubbing of the water which facilitates thorough deaeration, while at the same time permitting of the safe and effective use of relatively low pressure steam supplied through the bleeder outlet connection A to furnish the bulk of the heat required in heating the water to the final temp'erature desired. By supplementing the heat supplied to the chamber E through the tubes 6 with the heat of the steam supplied through the connection A, it is possible to 'exert a substantially greater water heating effect with ap aratus of given bulk than would be practically possible if all the heat were furnished by the steam in the tubes e. The system as a whole is well adapted for the utilization of low pressure and relatively inex ensive steam in the heater K, and avai able heat derived from the coolers L in supplying more or less of the heat imparted to the water.

While in accordance with the provisions ofv the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of my invention as set forth in the appendcombination therewith of feed water heating and deaerating apparatus comprising a chamber having an upper air and steam space and a lower water space, means for passing water of condensation from said condenser through said air and steam space in divided streams, a closed steam heater in the lower portion of said chamber, a connection for bleeding steam from an intermediate stage of said turbine into said heater, a connection for bleeding steam into the chamber above the water level therein from a stage of the turbine in which the steam is at a lower pressure than in the first mentioned stage, and means for discharging air from said air and steam space.

2. In a steam plant comprising a multistage steam turbine and a condenser receiving the main exhaust from said turbine, the combination therewith of feed water heating and deaerating apparatus comprising an air cooler, a chamber having an upper air and steam space and a lower water space, means for passing water of condensation from said condenser through said air cooler and thence through said air and steam space in divided streams, a closed steam heater in the lower portion of said chamber, a connection for bleeding steam from an intermediate stage of said turbine into said heater, a connection for bleeding steam into the chamber above the water level therein from a stage of the turbine in which the steam is at a lower pressure than in the first mentioned stage, and means for withdrawing air from said air and steam space, and discharging it through said air cooler.

3. In a steam'plant comprising a multistage steam turbine and a condenser receiving the main exhaust from the turbine, the combination therewith of a deaerating chamber having an upper steam and water space and a lower water space, a closed steam heater in the lower portion of said chamber, a second closed steam heater without said chamber, connections for bleeding steam from stages of the turbine at successii'ely lower pressures into the first mentioned heater and said second heater, respectively, means for passing water of condensation from said condenser through said second heater, and thence in dlvided streams through said air and steam space, and means for withdrawing air from said chamber.

4. In a steam plant comprising a multistage steam turbine, a condenser receivin the main exhaust from said turbine, an fluid coolers, the combination therewith of feed water heating and deaerating apparatus comprising a chamber having an upper air and steam space and a lower water space, means for passing water of condensation from said condenser through said fluid coolers and thence in finely divided streams through said air and steam space, a closed steam heater in the lower portion of said chamber, a connection for bleeding steam from an intermediate stage of said turbine into said heater, and means for discharging air from said air and steam space.

5. In a steam plant comprising a multistage steam turbine, the combination with said turbine, of feed water heating apparatus comprising a chamber having an upper steam space and a lower water space, means for passing water to be heated through said air and steam space in divided streams, a closed steam heater in the lower portion of said chamber, a connection for bleeding steam from an intermediate stage of said turbine into said heater, a connection for bleeding steam into the chamber above the water level therein from a stage of the turbine in which the steam is at a lower pressure than in the first mentioned stage, and a check valve in the last mentioned connection preventing back flow of steam through said connection from said chamber into the turbine.

Signed at Philadelphia, in the county of Philadelphia and State of Pennsylvania, this first day of November A. D. 1923.

GEORGE H. GIBSON.

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