US2663286A - Deaerating and evaporating unit - Google Patents

Description

Dec. 22, 1953 G. A. WORN 2,663,286

DEAERATING AND EVAPORATING UNIT Filed April 19, 1950 INVEN TOR.

atented Dec. 22, 1953 DEAERATING AND EVAPORATIN G UNIT George A. Worn, Greenwich, Conn., assignor to Y YThe Lummus Company, New York, N. Y., a cor# poration of Delaware Application April 19, 1950, Serial No. 156,791

2 Claims. (Cl. 122-417) l This invention relates to improved apparatus v'for preheating deaerating and evaporating a liquid such as water for example, and, in particular, boiler `feed water.

A steam generating plant commonly includes anlevaporator for removing impurities from raw feed water and also a separate deaerator unit (for preheating the feed water and removing air therefrom. Such a unit is usually a large and yexpensiveitem of the plant equipment and it ,imposes spaced requirements, a foundation for vsupporting it separately from the evaporator land heat insulated piping connecting it with the Ievaporator. p

important `object of the present invention isto provide for satisfactory embodiment of de#- ,aerating' apparatus and evaporating apparatus in asingle unit' and thereby reduce space requirements, eliminate the need for a separate foundationffor the deaerating apparatus, eliminate out- *.sidepiping' and substantially reduce the cost of thejdeaerating equipment. Y

l A further Vobject ofthe invention is to provide ianimproved unit including an evaporator and .deaerator equipment mounted in an advantageous *position* within the vapor space of thefshell of the evaporator. i y

A still further object of the invention is'to provide deaerating apparatus of improved design ffor embodiment in an evaporator unit. l Further objects and advantages ofthe invention will appear from the following description taken in connection with the accompanying draw- Q. In the drawing:

Fig'.l 1 isa side `elevation of an evaporator unit 'embodying the invention;

Fig; 2 is an enlarged vertical longitudinal secv tional view of the unit including the deaerating apparatus designed for two-stage operation;` Fig. 3 is a vertical cross section on the line l3---3 of Fig. 2; and

Fig. 4 is a vertical longitudinal, sectional view of a portion ofthe evaporator shell and deaerating apparatus designed for single-stage operation.

Referring to Figs. 1, 2 and 3, I designates an evaporator body, orY shell, of cylindrical form Vsupported in a horizontal position by cradles 2,. "One end of the shell is shown as convex and the opposite end as formed by a liat welded-on plate 3. Theshellends may be otherwise formed, however. At its upper side, the shell has a vapor 1 dome 4 with a vapor outlet nozzle 5. The lower Vportion ofthe Vshell provides a liquid space and lthe upper portionprovides a vaporspacefopen- 'deaerator device ving into the dome. Within said liquid space there lthe shell and through an opening 'I in the shell end plate 3. The outer ends of said tubes are secured to a tube sheet 8 bearing against the outer side of the plate 3, around the hole 1. A channel or header 9 bears against the tube sheet and has a steam inlet nozzle I0, a lcondensate outlet nozzle II and a pass partition between said nozzles. The channel and the tube sheet are bolted or otherwise detachably secured to the plate 3 so that the tube bundle may be withdrawn from the shell, through the opening 'I, when the tube sheet and channel are released from plate 3. The shell may have one or more manholes, one being shown at I2 in the convex end of the shell, to give access to the bundle and to the which will be described hereinafter. Y

Within the vapor space of the shell, at a posi- `tion substantially spaced from the vapor dome and its outlet, there is mounted a deaerator device D. In -the present disclosure, said device is located near the convex end of the shell and ritsmanhole I2. The device comprises a metal casing dening two side-by-side chambers I 3 and i Ill'separatedby a vertical wall I5. In the preslwall'20, thedividing wall I5 and the upper side V.of the shell I.

extends downwardly through an opening in the A feed watersupply pipe 2| shell and dips into a trough 22 within the chamber I3 and at the wall Il thereof. At the opposite side of said chamber and at a level below that of the trough 22 there is a trough 23 into which the partition wall I5 dips. rBetween said troughs there arebafile means to cause cascade flow of the water from the trough 22 to the trough A23 and to admit vapor tothe water at points kalong its course. Said baille means, asshown, is

tall upstanding baille plate 26 at the forward edge thereof, forms a shallow trough 21, the rear edge of each strip being bent upward to form the rear side of the trough, and the forward edge dipping into the trough 21 therebelow. The baffles 26 have numerous small perforations distributed over their area with the exception of the lower margin, and theupper margins of the baies are all curved in the same direction, as shown at 28. The bottom I8 of the chamber I3 has an opening 29 normally closed by a cover detachably secured to the bottom, as at 3I, and bearing a depending drain pipe 32.

Chamber I4 has a down spoutl 33 at the under side thereof and located at the wall 20.- Within the lower portion of said chamber there is a baffle assembly precisely like that within the chamber I3 and descending from the overflow side of the trough 23 to the down spoutV 33. In the drawing, corresponding elements of said two baie assemblies are correspondingly numbered. The baffle assembly within the chamber I4 forms, in effect, the lower side of the chamber and also 'defines the inlet for flow of vapor from the vapor space of the shell into the chamber I4. A vapor transfer pipe 34 of elbow form leads from an outlet orice 35 of the chamber I4 to an inlet orifice 36 of the chamber i3. The orifice 35 is spaced above the bailles 26 in chamber I4, and orifice 36 is spaced below the baiile strips 25 in chamber I3. Chamber I3 has at its upper side, an air vent through the shell I provided with a valve 3l'. A small bleed hole 3io may also be provided in the upper portion of the partition i5 to vent the upper portion of the chamber I4 to the chamber I3 and thereby prevent air trapping in chamber I4, above the orifice 3 5.

The deaerator device is detachably mounted within the shell I. Angle-irons 38 are kwelded to .the under side of the top of the shell and angleirons 39 welded on the outer side walls of the .chambers I3 and I4 are bolted, as at 4e, to the angle-irons 38. Gaskets 4I are fitted within groovesat the upper edges of the vertical walls of the casing and are adapted to be pressed against the shell I when the bolts connecting said angleirons are tightened. Of course, the casing may `be otherwise mounted and sealed. The chambers .I3 and 24 are also detachably connected to each other to part in a plane indicated by the line 42 of Fig. 2. The sidewalls I6 and I9 of said cham- .,bers have opposed vertical angle-irons 43 welded thereto and abutting in said plane. Bolts 44 re- Vleasably connect said abutting flanges. The various troughs and bafile `elements within each -chamber are preferably welded to the .adjacent walls of the chamber. In order to enable withdrawal of the feed water `supply pipe from the chamber I3 said pipe .may be provided, with a .welded-on collar 45 releasably secured to a seat on the shell, with an interposed gasket.

In the operation of the` unit the shell `I is kept charged with water to a levelsufficiently high to submerge the tube bundle and also the lower end of the .down-spout 33 and the drain pipe 32. -Steam is charged to the tubes of the bundle through the channel .nozzle I0 and condensate is discharged from the tubes through the nozzle II.

vThe raw feed `water enters the water space of' the shell through the pipe 2I, the chamber I3, the

'chamber I4 and the down-spout 33. Most of the steam `or 4vapor generated within the shell flows v.through the dome and is discharged through the outlet 5. Some of the steam however, enters the :deaerator device and contacts the water cascad- 4 ing therethrough to the down-spout to preheat the water and release the air therefrom.

All of the feed water charge to the evaporator is delivered through the pipe 2| which rst delivers into the trough 22 in the chamber I3. The water overflows from said trough and descends over the baffle element 24 and the baille elements 25 in succession to the trough 23 where it forms a seal between ythe chambers I3 and I4. The overflow from trough 23 descends over the bale elements 24 and 25 of chamber I4 and passes to the down-spout 33 for delivery to the liquid space within thev shell. In both chambers there is a slot-like spacebetween the upturned rear edge of eachl baffle element 25 and the element overlying it. The vapor flows through said spaces and casts the water descending over the elements 25 upwardly over the rear face of the upstanding baffles,r 26 in succession. Through the perforations of the baiiies 26 the water flows forward toward the down-spout. Thereby, a desired turbulence and spreading of the water is obtained for' efiicient transfer of heat from the vapor to the water to effect release of air from the water.

Chamber I3 may be considered the first-stage deaerating chamber for the reason that the feed water `iiows first through this chamber and is there i'irst preheated and deaerated. The vapor first enters the chan'lbei"V I4 which is in direct communication with the vapor space of the shell, through the space between the baille elements 25. Vapor which has not been condensed in chamber I4, together with released air, flows through the transfer pipe 35 to the chamber I3 for contact with the water iiowing therethrough. The air escapes from 4chamber I3 through the vent valve 31.

When two-stage operation ,is not requiredA the chamber I3 alone maybe employed, as shown in Fig. 4. The said chamber may be readily adapted for single-stage service b y .omitting the transfer pipe 34, blanking the orice 38 with a cover 36a and omitting the cover' 30. Then, vapor may enter directly from the vapor space of the shell through the opening 29, and the water overow from the trough 23 may fall directly to the water space of the shell.

In both singlefstage and double-stage employment of the deaerator the chamber-forming casing thereof is surrounded by hot vapor within the shell. Thereby, substantial additional heat input may be obtained by conduction of heat through the metal walls of the casing to the deaerating zone. Preheating and deaerating are thereby substantially assisted. They are further assisted by the highly efficient baille arrangement for obtaining contact of the vapor with the water. The efliciency of .the bafle arrangement also ,enables very compact construction of the deaerator so that it may not objectionably reduce the vapor space within the shelll I. It may be conveniently mounted near one end of the shell out of vthe way of the Vmain .course of the vapor to the .dome or shell outlet. ,The compactness of the deaerator also facilitates its installation `and removal. A single-stage deaerator may be inserted or removed through a manhole, such as the one shown at I2, ,and the :two-.stage deaerator .may be inserted yor removed through the tube bundle .opening l.

The embodiment of the `deaerator and the .evaporator in a unit also eliminates outside space requirements, eliminates the need of a separate evaporator and the deaerator. The design of the deaerator is also such as to render its cost of construction comparatively low.

1t is to be understood that the present disclosure of the invention is merely illustrative and in nowise limited and that the invention compre-'f hends such modications as `will fall within the scope of the appended claims.

I claim:

l. A self-contained evaporator and deaerator unit comprising a shell forming the evaporator body and affording a space for charge liquid Within the lower portion thereof and an overlying vapor space, heating means within the said liquid space to vaporize the liquid therein -by indirect heat exchange comprising a bundle of tubing and connections for circulating a heating iluid therethrough, the shell having a vapor outlet leading from said vapor space; and deaerating apparatus Wtihin said vapor space and comprising casing means oset from said vapor outlet of the shell and forming a first-stage deaerating chamber and a subsequent-stage deaerating chamber, said ilrst-stage chamber having an inlet for the charge liquid and a gas outlet, said subsequentstage chamber having an outlet for said liquid in delivery communication with said liquid space Within the shell, said subsequent-stage chamber having also a vapor inlet open to said vapor space of the shell `and a vapor outlet in delivery communication with said first-stage chamber, a vapor-excluding connectionfor delivery of said liquid from the first-stage chamber to the subsequent-stage chamber and forming the liquid outlet for the former chamber and the liquid inlet for the latter chamber, and baille means in the path of now of said liquid from the liquid inlet to the liquid outlet of each chamber, said baiile'means being correlated with the vapor inlets oi the chambers to effect deaerating contact of the admitted vapor with the liquid.

2. A self-contained evaporator and deaerator unit comprising a shell forming the evaporator body and affording a space for charge liquid within the lower portion thereof and an overlying vapor space, heating means Within said liquid space to vaporize the liquid therein by indirect heat exchange comprising a bundle of tubing and connections for circulating a heating iluid therethrough, the shell having a vapor outlet leading from said vapor space; and deaerating apparatus Within said vapor space and comprising casing means offset from said vapor outlet of the shell and forming adeaerating chamber, said chamber having an inlet for said charge liquid, a vaporexcluding outlet for said liquid from the chamber in delivery communication with said liquid space within the shell and a vapor inlet for the chamber in delivery communication with said vapor space Within the shell, and baile means in the path of flow of the liquid from said liquid inlet to said outlet of the chamber and including portions spaced along said path and extending cross- Wise thereof and having numerous perforations to cause divided W of the liquid, said baille means being correlated With the vapor inlet of said chamber to effect deaerating contact of the admitted vapor with the liquid in said divided ow thereof, said baile means being spaced above the bottom of said chamber, said vapor inlet being located to admit vapor into the space beneath the baille means, and an air outlet from said chamber above the baille means.

GEORGE A. WORN.

References Cited in the ille of this patent UNITED STATES PATENTS Number Name Date 365,093 Petzold June 21, 1887 418,428 Upton Dec. 31, 1889 569,362 Struben Oct. 13, 1896 692,073 Reiser Jan. 28, 1902 752,270 Urbanek Feb. 16, 1904 1,064,806 Yarnall June 17, 1913 1,555,435 Rohrer Sept. 29, 1925 1,579,444 Gunther Apr. 6, 1926 1,767,456 Hulsmeyer June 24, 1930 2,354,932 'vl/'allier et a1. Aug. 1, 1944 2,401,569 Koch June 4, 1946 2,510,590 Kraft June 6, 1950 2,582,134 Kimmel vet al. Jan. 8, 1952 FOREIGN PATENTS Number Country Date 641,664 Germany Sept. 2l, 1938

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