US921878A - Steam-superheater. - Google Patents

Description

L. B. NUTTING.

STEAM SUPERHEATER.

APPLICATION FILED AUG. 2a, 1906.

Patented May-18, 1909.

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UNITED STATES AN I LOUIS B. NUTTING, OF PELHAM, NEW YORK, ASSIGNOR TO POWER SPECIALTY COMPANY OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

STEAM-SUPEBEEATEB.

Specification of Letters Patent.

Patented May 18, 1909.

Application filed August 28, 1906. Serial No. 832,312.

To all whom it may concern:

Be it known that I, LoUIs B. NUTTING, a citizen of the United States, residing at Pelham, in the county of V-Vestchester and State of New York, have invented certain new and useful Improvements in Steam-Superheaters, of which the following is a specification.

In a well known type of superheater the elements or pipes which conduct the steam are arranged in pairs, connected at one end to the inlet header and outlet header, respectively, and at the other end to a return header. The high temperature, and high internal ressure, to which superheaters are unavoida ly subjected, require that such joints be constructed in the most careful manner. Furthermore, it has come to be generally accepted as good practice to incase superheater elements or pipes in closely fitting ackets or casings of cast iron, usually in the form of cast iron rings shrunk in place on the pipe, forming a corrugated element with large heating surface, the outer portion of'the element being of cheap cast metal, which fully protects the strong and more costly inner foundation pipe.

The object of my present invention is to provide a superheater element in which the use of areturn header is entirely obviated, and a further object of the invention is to provide a protective casing for elements of this kind, that is, in which no return header is used.

The invention itself, which consists in the novel featuresof construction and com inations of parts hereinafter described, and

more partlcularly pointed out in the claims, will be more readily understood from a description of the preferred embodiment, which is illustrated in the annexed drawing. Therein,

Figure l is a plan View, with part of the bend casing broken away, and Fig. 2 is a section on line a-a,.

The superheater element consists essentially of an inner or foundation pipe, indicated by 1, and an outer protective casing or jacket, referably of cast metal. In the element il ustrated, one end of the foundation ipe, say the end 2, is joined to the inlet header, not shown, from which steam enters This end of the element may ated the inner end.

the element. be conveniently desi At the outer end of t e element the pipe is usually connected to a return header, to the other side of which is connected a return pipe, leading back to the inner end of the element and there connected to the outlet header, not shown. 'It is of course clear that the element is subjected to a high temperature and to high internal pressure; and to withstand the strains resulting therefromthe joints at the headers must be very carefully constructed. I therefore propose to improve the superheater by eliminating the return header. In lieu of such header, and instead of using two pipes, I employ asingle pipe, bent into U-shape at the point where the steam is to return, as indicated at 2, and connected at its ends to the inlet and outlet headers respectively.

The bend in the pipe is covered by a casing constructed preferably as follows: The bend casing or jacket is indicated at 3, and as shown is semicircular in plan and circular in cross section, to conform as closely as possible to the pipe which it incloses. The casing, whichis preferably of cast iron, while the inner pipe is of steel, is formed of two sections, 4, 5, separable on the line 6. The ends of the casing are rabbeted to receive binding rings 7, 8, which are just large enough that when heated they can be slipped,

into place. Upon cooling the rings con- .tract and bind the two parts of the casing firmly and securely together. On the curve of the casing the sections are provided with bosses 9, 10, through which passes a pin 11. Extending transversely through the bosses and the said pin are pins 12, 13. This ar rangement is very satisfactory, inasmuch asthe points where the pins engage each other terial of good heat conductivity. For this purpose a gluantity of iron filings is mixed with a sma quantity of clay and sufficient water to form a still dough or paste. The inner surfaces of the two casing sections are then coated with a layer of this material and placed in position, so that when the sections are bound together the plastic material will be brought intointimate and firm contact with all the" parts, any slight excess of ma terial being squeezed out at the edges of the halves. The heat to which the superheater is subjected vaporizes the water in the packing materialand causesa slight rusting of the iron,,bi1t the amount of water is so small that rusting is practically negligible. wise the quantity of clay need be very small, so that the'packing will be substantially all iron and therefore of good heat conductivity.

Fitting firmly against the binding rings,- 7, 8, are retaining rings 14, 15, shrunk on the inner pipe, to revent any possible displacement of the inding rings. From the retaining rings tothe inlet and outlet headers the two legs of the pipe are covered with ta cred cast iron rings 16, applied hot and contact with the pi e.

contact WlthBfiGh 0t er, and hence make the pipe corrugated, in effect, with large heating a owed to contract by cooling into very firm surface From the foregoing'it will behseeiiithafl j -there are no steam joints Whatever-fatgthe: return: end ofthe element. The; inner or.

" foundation pipey which furnishes to a large extent the, strength'of the element is 'inclosed in a cast Iron casing which fully protects the pipe. At the 's'ame time the casing is compipe.

' tent thereof, and heat conducting protective paratively inexpensive, and damaged parts thereof maybe replaced with little trouble and at slight-cost, whereas if the steel pipe were ex 'osed it would suffer rapid deterioration an injury to any part. of it could be repaired only by substituting an entire new coverings onthe straight pipes in close con tact therewith and the said protective casing.

Like- These rings are in 2. A super-heating element, comprising a foundation pipe including straight 1pc portions united by aU-bend, a sectiona protective casing inclosing the U-bendthroughout the curved portions thereof, and coverings for the straight pipe sections, said last mentioned coverings being separate and inde-- pendent from the casing for the U-bend.

3. A superheater element comprising in combination a bent foundation pipe, a protective heat-conducting casing inclosingthe bend of the pipe, and a packing of heat-conducting material between the casing and the pipe, as set forth.

4. A superheater element com rising in combination a bent foundation pipe, a protective heat-conducting casing for the bend of the pipe, constructed in sections parallel With the bend, and binding rings around the ends of the sections to secure the same together, as set forth.

5. A superheater element comprising in combination a bent foundation, a protective heat-conducting casing for the bend of the pipe conforming to contour of the bend andv kconstructed in two and binding rings s firunk on the ends of the arts parallel to the bend,

I parts-tov secure the same together.

v6..A.,s l lperheater element comprising in comblnation a bent foundation pipe and a protective heat-conducting casingv for the bend'of the. ipe, consisting, of parts or sections paralle to the bend and conforming to the. curvature thereof, provided with registering bosses, a pin extending through the bosses, cross pins extending" through the bosses and the first-mentioned pin, and binding rings on the ends of the casing to bind the sections thereof together, as set forth.

7.. A superheater element comprising in combination a foundation pipe having a return bend, a protective heat-conducting cas-,.

ing inclosing the bend of the pipe, and a pluducting rings on the remaining portions of ty of independent protective heat-com the pipe in contact with the tter and in heat conducting relation to the said casing,

as set forth.

LOUIS B. NU'rTINd-I Witnesses;

J. FosrERSYMEs, W. E. Down, Jr.

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