US1962183A - Hot well - Google Patents

Description

June 12, 1934. R. N. EHRHART HOT WELL Filed Dec. 6, 1930 2 Sheets-Sheet.A 1

lNvENTo @agi a t ATTORNEY June 12, 1934. R. N. EHRHART HOT WELL 2 Sheets-Sheet 2 Filed Dec. 6, 1930 CSG@ SQSB

CCC s QOQOM ooo d COOLING SURFACE IN SQ. FT.

6 0%, o. a 5a Z Patented June 12, 1934 UNITED STATE-S PATENT OF F IC E This invention relates to condensers and more particularlyrelates to hot wells for surface condensers.

In relatively large surface condensers there is a material loss in pressure as the fluid to be condensed flows through the tube nest. This pressure loss is not so pronounced in small condensers because of the shortness of the path of flow but in large condensers having iiow paths many feet in length, this pressure loss may be as great as one-half an inch of mercury and losses of from two-tenths to three-tenths of an inch are not uncommon. Inasmuch as surface condensers usually receive vapor at the top of the condenser and the vapor flows downwardly through the condenser, the pressure loss referred to generally results in a lowering of the temperature of the condensate. The region or zone of lowest vapor pressure and temperature is consequently adjacent the lowermost portion of the condenser and since the condensate must drop through this region, the temperature of the condensate will be substantially the same as the temperature of this region. Many cases have come to my attention where the temperature of the condensate is as much as twenty degrees Fahrenheit less than that of the vapor entering the condenser. In such cases the dissolved oxygen content of the condensate is so high that its corrosive action is very objectionable in high pressure boilers and economizers.

My invention electually overcomes these disadvantages and provides an improved form of hot well which both heats and degasiiies the condensate flowing thereinto.

To accomplish this heating and degasication of the condensate I cause some ofthe steam entering the condenser to flow into the hot well Without coming in contact with the condenser tubes and to then flow counter-current to and in contact with the condensate. I distribute the condensate in the hot well so as to obtain an intimate contact of the steam and condensate and so as to prevent the steam from short-circuiting through the hot well without coming into contact with condensate. I provide one or more vents for the hot well and locate these vents so that they communicate with the condenser at a pointwhere the pressure is lower than in the hot well and where the vapor escaping therefrom will iiow over cooling tubes and be condensed before it reaches the main air exhausting means of the condenser. I proportion the aggregate flow area of these vents so that effective degasication and heating of the condensate and eflicient condenser operation is obtained 'over wide ranges of capacity of the condenser.

The character of the invention will become apparent from the following description and the accompanying drawings forming a part thereof and which illustrates a preferred form of the invention. Inasmuch, however, as many modiiications may be made i'n the form Vherein disclosed without departing from the spirit of the invention, it is understood that the invention is not limited except by the scope of the claims appended hereto.

In the drawings:

Fig. 1 is a more or less diagrammatic view in transverse section of a single pass surface condenser embodying my invention,

Fig. 2 is a sectional View on line 2-2 of Fig. 1, and

Fig-3 is a graphic representation of the relation between the cooling surface of a condenser and the aggregate ilow area of the vents between the hot well and the condenser.

Referring to the drawings, reference character l0 indicates the shell of a single pass surface condenser having a plurality of longitudinally extending cooling tubes 11 therein through which water or other suitable cooling mediumV passes. The condenser has a steam inlet 12 and oppositely disposed gas outlets 13 connected to the sides of the shell 10. Battles 14, disposed within the tube` nest, and each extending from the shell 10 from a point above the gasoutlets 13 toward the central portion of the bottom of the shell, direct the flow of vapors through the tube nest from the condenser inlet to the outlets. The bottom c'f the condenser shell is provided with a condensate` outlet 15. A steam conduit 16 extends through the tube nest and has its inlet end l'l in the zone of the condenser inlet 12 and its outlet end 18 disposed in the condensate outlet 15.

The hot well of my invention comprises a shell 19 which is secured to the condensate outlet 15. As shown, the shell 19 is cylindrical in form but it will be apparent that other shapes' or forms of shell may be utilized if desired. The bottom of the hot well shell is provided with an outlet 2o to which a condensate pump', not shown, is connected. A steam conduit 21 extends longitudinally of and is centrally disposed with respect to the' hot well shell 19` and has its upper end secured tothe lower end 18 of the conduit 16 and its lower end disposed in the lower portion of the shell 19.n A dished. plate 22 ofV circular or other configuration and` having a central aperture into which the lower end of conduit 21 nts, is secured loo to the conduit 21 so as to surround the lower end thereof. Plate 22 is provided with a plurality of apertures 23 preferably arranged in concentric circles of dilerent diameters. The number and size of these apertures may be varied as desired. Another dished plate 24 of circular or other desired configuration is disposed above plate 22 and is secured to the hot well shell 19. Plate 24 is provided with a central aperture 25 which is larger in diameter than the outside diameter of conduit 21 and with a laterally extending inner peripheral ange 26. Plate 24 is also provided with an upstanding annular flange 27 intermediate the shell 19 and the flange 26 for a purpose presently to appear. Between the flanges 26 and 27, plate 24 is provided with a plurality of apertures 28 preferably arranged in a manner similar to the apertures 23 in plate 22. The number andsize of these apertures may also be varied as desired. A plate 29 is secured adjacent the upper end of conduit 21 and is disposed in the hot well above the plate 24. Plate 29 has a downwardly extending peripheral iiange 30 which is disposed between the shell 19.0f the hot well and flange 27 of plate 24. Plates 24 and 29 together with their flanges 27 and 30 form a manometric seal 31. Plate 29 is provided with one or more (two are shown) vents 32 which have their upper ends c'overed by caps 33. The cross-sectional or ow area of the vent 32 where only one vent is utilized or the aggregate cross-sectional or ow area of the vents 32 where more than one vent is used, is preferably less than that of the steam conduit 2`1 so as to prevent overloading of the after cooler and the gas exhausting means.

The apertures 23 and 28 in plates 22 and 24 are proportioned so that with a full flow of condensate the level of the condensate on plate 22 will be approximately at the upper or outer edge of the plate. At partial condensate flow the level of condensate on plate 22 will be at a lower point, but at any load there will always be an annulus or a curtain of ne streams of liquid surrounding the discharge end of conduit 21 and an effective contact of steam and condensate will be obtained at any rate of condensate flow.

The conduits 16 and 21 should be so proportioned in cross-sectional area that the loss of pressure therethrough is maintained at a low value preferably not to exceed approximately one one-hundredth of an inch of mercury when the vapor flow is great enough to heat the full condensate flow. The vents 32 are located so that they are in communication with a point in the condenser where the pressure is lower than the pressure in the hot well. I preferably have the vents 32 communicate with the condenser at a point where any vapor escaping therefrom will ow over cooling tubes either within the condenser or in an external cooler so that this vapor will be condensed before it reaches the main air exhausting means of the condenser.

From the foregoing description the? operation of the hot well will be apparent. The condensate from the condenser flows through condensate outlet 15 into the hot well onto plate 29 and into manometric seal 31. It overflows the flange 27 onto the apertured portion of plate 24 and through the apertures 28 to plate 22, thence through the apertures 23 into the bottom of the hot well. Some of the steam entering the condenser` flows into conduit 16 and passes therethrough into conduit 21 and into the bottom of the hot well. The steam is forced to pass through the curtain of condensate streams from the apertures 23 in plate 22 and passes upwardly in the hot well around the periphery of plate 22 and through the curtain of condensate streams from the apertures 23. The steam remaining uncondensed will flow through central aperture 25 in plate 24 and through vents 32 into the lower part of the condenser where it will flow over the tubes 11 and be condensed and the condensate will flow into the hot well. The condensate in the bottom of the hot well will be drawn off through outlet 20. With this arrangement I obtain effective degasifcation and heating of the condensate over great ranges of capacity.

The extent of degasication of the condensate is inuenced by the size of the vents 32. If the vents are proportioned so that but a small amount of vapor hows through them, effective degasification will not be obtained. However, by proportioning the aggregate flow area of the Vents so that they will pass not less than ten times as much vapor as the air content of the condensate, satisfactory degasication is obtained. In a commercially air tight condenser condensing approximately 400,000 pounds of condensate per hour` the air content of the condensate fed to the hot well would normally not exceed 11/2 pounds per hour. It will, of course, be understood that in condensers having a relatively large pressure drop therethrough there will be relatively large pressure differences to force vapor through the vents 32, but in condensers having a relatively small pressure drop there will be only a small pressure difference to force vapor through the vents. Consequently, the vent openings on large condensers with large pressure drops will not have to be as large proportionally as the vent openings in smaller condensers having smaller pressure drops.

In condensers of normal commercial design for handling about ten pounds of steam per square foot of cooling surface, I find that for effective degasication the minimum aggregate ilow area of the vents 32 should be not less than that indicated in the following table and shown graphically in Figure 3:

It will be understood that the hot well herein disclosed is not limited in its application to single pass surface condensers but is applicable to multi-pass and to other types of surface condensers as well.

What I claim is:

1. A heating and degasifying hot well comprising a steam inlet and a dished apertured plate surrounding the steam inlet, the hot well being provided with a vent having a cross-sectional area smaller than that of the steam inlet.

2. A heating and degasifying hot well comprising a steam inlet and a plurality of dished apertured plates surrounding the steam inlet, the hot well being provided with a vent having a crosssectional area smaller than that of the steam inlet.

3. A heating and degasifying hot well comprising a central steam inlet and a dished apertured plate surrounding the steam inlet, the hot well being provided with a vent having a cross-seetional area smaller than that of the steam inlet.

4. A heating and degasifying hot well comprising a steam inlet and a dished apertured plate surrounding the steam inlet, the hot well being provided with a vent having a cross-sectional area smaller than that of the steam inlet, said vent having its outlet end in communication with a point of pressure which is lower than the pressure in the steam inlet.

5. A heating and degasifying hot well comprising a steam inlet and a plurality of dished apertured plates surrounding the steam inlet, the hot well being provided with a vent having a cross-sectional area smaller than that of the steam inlet, said vent having its outlet end in communication with a Zone in which the pressure is lower than the pressure in the steam inlet.

6. A heating and degasifying hot well comprising a steam inlet, an apertured plate surrounding the inlet and a liquid seal to prevent escape of vapors from the hot well, the hot well being provided with a vent having a cross-seetional area less than that of the steam inlet.

'7. A heating and degasifying hot well comprising a central steam inlet, a dished, apertured plate surrounding the inlet, a second dished, apertured plate surrounding the steam inlet and disposed above the rst mentioned plate and a liquid seal to prevent the escape of steam from the hot well, the hot well being provided with a vent having a cross-sectional area less than that of the steam inlet and having its outlet end in communication with a region of lower pressure than that in the steam inlet.

8. A heating and degasifying hot well comprising a central steam inlet, a dished, apertured plate surrounding the inlet, a second dished, apertured plate surrounding the steam inlet and disposed above the iirst mentioned plate and having a central aperture larger than the steam inlet to permit the passage of vapors between said plate and the steam inlet and a liquid seal to prevent escape of vapors from the hot well, the hot well being provided with vent means having an aggregate cross-sectional area less than the cross-sectional area of the steam inlet, said vent means discharging into a region in which the pressure is lower than that in the steam inlet.

9. A heating and degasifying hot well comprising a steam inlet and a dished apertured plate surrounding the steam inlet, the hot well being provided with a vent having a cross-sectional area smaller than that of the steam inlet and adapted to pass not less than ten pounds of vapor for every pound of gas discharged from the hot well.

10. A heating and degasifying hot well comprising a steam inlet and a plurality of dished apertured plates surrounding the steam inlet, 100 the hot well being provided with a vent having a cross-sectional area smaller than that of the steam inlet and adapted to pass not less than ten pounds of vapor for every pound of gas discharged from the hot well.

11. A heating and degasifying hot well comprising a central steam inlet and a dished apertured plate surrounding the steam inlet, the hot well being provided with a vent having a cross-sectional area smaller than that of the ll@ steam inlet and adapted to pass not less than ten pounds of vapor for every pound of gas discharged from the hot Well.

RAYMOND N. EHRHART.

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