US1768058A - Superheating of interstage steam - Google Patents

Description

June 24, 1930. 0. H. HARTMANN 1,768,058

SUPERHEATING OF INTERSTAGE STEAM Filed July 11, 1928 2 Sheets-Sheet 1 Fig.7.

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June 24, 1930. I o, HARTMANN 1,768,058

SUPERHEATING OF INTERSTAGE STEAM Filed July 11, 1928 2 SheetsSheet. 2

Patented June 24', 1930 omen STATES OTTO H. HARTMANN, OF CASSEL-WILHELMSHOHE, GERMANY, ASSIGNOR TO SCHMIDTSCHE HEISSDAMPF-GESELLSCHAFT MIT BESCHRAINKTER HAF'IUNG, OF

CASSEL-WILHELMSHOHE} GERMANY, CORPORATION OF GERMANY surnnunermo or m rnnsraen STEAM Application filed July 11, 1928, Serial No. 291,802, and. in Germany July 29, 1927.

My invention relates to an arrangement for the superheating of interstage steam, more particularly in marine steam plants, by means of a heat carrier in the form of steam in marine boilers with a return for the hot gases. The superheatimg of the interstage steam of multi-stage steam engines reversing chamber in the form of a radiation boiler (see Figures 1 and 2 of the U. S. Patent No. 1,618.230. filed Dec. 15. 1920, and

granted to Wilhelm Schmidt). The advantage of such an arrangement lies mainly iii this that for the superheating of interstage steam by high-pressure condensing tre'sh steam it is suflicient to produce comparatively small quantities of heating steam and that v consequently the heating surface to be built in can be made comparatively small. This heating surface absorbs from the heating gases only-so much heat that .a suflicient quantity of heat still remains available for the required-high superheating of the working steam produced in the main boiler, which" superheating is ,effected in the heating tubes ofthe marine boiler which are provided with comparatively superheating tubes. The

7 small reduction in the super-heating of the working steam caused by the building in of the heating elements of the high-pressure auxiliary boiler is morethan compensated by the advantage gained by the high superheating of the interstage steam in the low pressure stage.

existing marine boiler installations in order to'improve theiroutput in a known manner by constructing into the existing engine a low pressure stage, more particularly an exhaust-steam turbine, and superheating the interstage steam. The obvious solution, of

building the heating coils of the high-pressure auxiliary boiler in the smoke box attached to the chimney, in which there is suflicient space for accommodating a comparatively large heating surface, does not come into question since the heating gases before arriving at this point have supplied too much heat to the'heating surface of the main boiler and to the superheating elements builtin the a heating tubes.

According to my present invention the problem is satisfactorily solved by the heated part of the auxiliary steam generator lying in the reversing chamber being construct ed, in a manner well known in connection with superheaters, viz., as heating coils with U-shaped return bends which are inserted from the outside into the reversing chamber. In single ended Scotch boilers, the U-shaped bends of the heating coils are inserted through flanged sockets which are provided after removal of thestaybolts between the end of the boiler and the wall of the reversing cha'.nber.. In the case of the double-ended Scotch boilers, according to one suitable form of construction, the heating coils of the auxiliary boilenwhich generates the heating steam for the superheating of the interstage steam are inserted with their reversing ends into the reversing chamber, which lies in the centre, through a portion of the heatingtubes of the working boiler, the remaining portion thereof being provided with the superheating coils of the'workin'g boiler.

The accompanying drawings illustrate diagrammatically and by way of example the two forms of construction above referred to, Figures 1 and 2.be1ng a sect1onal elevation and end view respectively of the first form of construction and Figure 3 a sectional elevation of the second form of construction.

Referring to Figures 1 and 2 Whichillustrate an existing single-ended Scotch boiler, the staybolts between the end 1' of the boiler staybolts whilst they allow at .the same time the tubes of the heating coils 4 of the auxil-' iary boiler to be passed through. The auxiliary boiler is provided with an upper drum 5and a lower Water collecting drum 6 and is partly filled with the heat carrier, for instance distilled water. The water circulates in a closed cycle through the heating coils of the interstage superheater 7 provided on the engine, in the direction of the ,arrows, thereby changing its physical state, the condensate being returned through the pipe 8 into the drum 5. In normal operation the whole of the heating steam passes through the pipes 9 and'lO and over an automatically acting stop valve 11 into and through the interstage superheater 7. However, when the pressure and temperature in the auxiliary boiler exceeds the normal values, the valve 11 opens automatically, so that the eX- cess of heating steam passes in a known manner througha heating coil 12, thereby giving up its excess heat to the water of the working boiler 1. The superheater 13 for the working steam generated in the boiler 1 is built in aknown manner in the heating tubes 14; of the working boiler. heating gases have passed through the flue tube 15, they give up a portion of the heat,-

which they 'still'contain in large quantity, to the heating coils 4 of the auxiliary boiler which project into the reversing chamber 2, so that the heating surface of the auxiliary boiler required for the interstage superheating "iscomparatively small This permits the heating surface required for the auxiliary boiler to be subsequently incor orated in a simple manner in an existing single-ended marine boiler. The places of insertion of the heating coils are made air-tight in a suitable manner, for instance, by 'means of divided plates with asbestos insertions.

In the case of a double-ended Scotch boiler, such/ as illustrated in Figure 3, the carrying out of the invention is even more simple in so far as a portion of the heating tubes 14 of" the boiler can be,used for, the passage of the heating coils of the auxiliary boiler, in order to permit the return bends of the heating coils to project into the reversing chamher 2. Although-i n this form of construction the heating coilsare lon er and ass through some of the heating tub which otherwise the superheating tubes for I the superheating of the working steam would be accommodated, this is only an apparent disadvantage, when it is borne in mind that by incorporatingan exhaust steam turbine and providing for. the superheating of interstage steam by means of high-pressure fresh steam, the steam consumption is reduced to suchan extent that the reduced superheating After thees of t 'e boiler, in

nveaoae surface more than suffices for the smaller amount of Working steam to be generated per hour. Otherwise the construction is the same as that shown in Figure 1, for which reason the same reference letters have been used in both drawihgs and the arrangement need not be further described. I I

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed. I declare that what I claim is:

1. An arrangement for the superheating of interstage steam in marine steam boilers provided with a reversing chamber for the hot gases and having live steam superheater elements arranged in its heating tubes, by means of a heat carrier in the form of steam which circulates in a closed cycle through its steam generator and the heating coils of the interstage superheater and which is produced by an auxiliary steam boiler having its heated part lying in the reversing chamber, the said heated part projected into the reversing chamber from the outside thereof.

.2. An arrangement as claimed in claim 1 used in connection with double-ended Scotch boilers, in which the heated part comprises coilshaving U-shaped return bends which are inserted into the reversing chamber ly ing in the centre of the working boiler through a portion of the heating tubes of the working boiler, the other portion of which accommodates the superheating coils of a live steam superheater for the working steam.

3. An arrangement for the superheating of" interstage steam in marine boilers provided with a reversing chamber for the hot gases and havinglive steam superheater elements arranged in its heating tubes, by means of a heat carrier in the form of steam which circulates in a closed cycle through its steam generator and the heating coils of an intersaid heated part being constructed in theform of heating coils having U-shaped return bends, each of the U-shaped return bends being introduced into the reversing chamber through an individual opening in the wall thereof.

Intestimony whereof I have aflixed m signature.

OTTO H. HARTMANN.

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