US2035763A

US2035763A - Superheater arrangement

Info

Publication number: US2035763A
Application number: US25266A
Authority: US
Inventors: Eric A Robinson
Original assignee: Superheater Co Ltd
Current assignee: Superheater Co Ltd; Superheater Co
Priority date: 1933-10-26
Filing date: 1935-06-06
Publication date: 1936-03-31
Anticipated expiration: 1953-03-31

Description

March 31, 1936. E. A. ROBINSON SUPERHEATER ARRANGEMENT Filed June 6, 1935 2 Sheets-Sheet 1 r I L INVENTOR E/P/c A. Roe/M50. BY Q 1 W ATTORNEY Patented Mar. 31, 1936 UNITED STATES SUPERHEATER ARRANGEMENT Eric A. Robinson, Marylebone, London, England, assignor to The superheater Company, New

York, N. Y.

Application June 6, 1935, Serial No. 25,266 In Great Britain October 26, 1933 7 Claims.

This application relates to improvements in the steam superheating installations of steam generators. It is in part a continuation of United States application 748,457, filed by me on October 16, 1934.

superheating installations are known wherein the superheater as regards its width across the boiler is divided into two sections which are arranged in parallel, and may be termed the righthand and left-hand superheaters, and in which each of said superheaters comprises a primary section and a final section, and it is to superheater installations of this character that the improvements according'to the present invention are directed.

One object of the present invention is to provide a method of, and means or apparatus for, compensating for the efiect on two superheaters arranged side by side across a boiler, and operating in parallel, of differences in firing across the boiler, in order to avoid material differences between the temperatures of the steam delivered by the respective superheaters, and, it may be, prevent excessive temperature in the secondary or final section of either superheater.

The invention resides primarily in a method of compensating for the effect on two steam superheaters arranged side by side across a boiler and operating in parallel, of differences in firing across the boiler, consisting in dividing each superheater into a primary section and a secondary or final section and heating the primary section of one superheater and the secondary or final section of the other superheater by the products of the combustion of fuel at one side of the boiler and heating the remaining sections of the two superheaters by the products of combustion of fuel at the other side of the boiler. Further, I have hereinbelow disclosed one form of my invention in connection with an arrangement of desuperheaters. However, I donot claim anything herein as to the manner of using desuperheaters or as to their arrangement, it being known to employ desuperheaters between two sections of a superheater and the details of the desuperheater shown forming no part of my invention, being disclosed in patent to Andre Huet, No. 1,964,060, June 26, 1934.

. In addition the invention consists in apparatus for superheating steam as defined in the claims which will appear hereinafter, and as will now be described with reference to the accompanying drawings, in which Fig. 1 shows in diagrammatic plan a steam superheating installation equipped with temperature control means, certain of the pipes leading to and from the desuperheaters of the installation being omitted for simplicity of illustration;

Fig. 2 is a diagrammatic elevation of the installation shown in Fig. l, and including the sev- 5 eral pipes omitted from that figure;

Fig. 3 is a fragmentary view showing a modification in the arrangement of certain parts, as will be described hereinafter;

Fig. 4 is a diagrammatic plan view of a modi- 1O fied arrangement of the superheater sections;

Fig. 5 is a lateral elevation thereof; and

Fig. 6 is a view similar to Fig. 5 showing a modification of the form of Fig. 5.

Referring to the drawings, the invention is shown therein, by way of example, as applied to the superheater of a water tube boiler of the semi-vertical type, but it is to be understood that the invention may be applied to the superheaters of boilers of other types. y

In the embodiment of the invention shown in Figs. 1 and 2, the installation comprises two superheaters each consisting of a primary section and a secondary section. The primary sections comprise inlet headers I, 2, collecting headers 3, 4, and elements 5, 6, whilst the secondary sections comprise distributing headers I, 8, outlet headers 9, l0, and elements ll, l2.

The superheater elements are distributed across the boiler, and to obtain an eflicient distribution of steam to the elements of each superheater steam is fed to one end of the inlet or distributing

header

1 or 2, or 1 or 8 of a superheater, and is withdrawn from the opposite end of the collecting or

outlet header

3 or 4, or 9 or 10, of such superheater, this method of steam distribution to superheater elements being well known. The collecting header 3 or 4 of a primary superheater is connected to the distributing header 1 or 8 of a secondary superheater at the opposite side of the boiler, that is to say the left-hand primary superheater supplies steam to the right-hand secondary superheater and the right-hand primary superheater supplies the steam for the left-hand secondary superheater. By this arrangement of cross-connection of the superheaters variations in firing as between the two sides of the boiler are compensated for, so that uneven firing across the width of the boiler will not cause material difierence in the temperature of the steam delivered by one secondary section as compared with that delivered by the other secondary section.

In Fig. 1, a steam and water drum I3 is shown, whilst in Fig. 2 there isshown also a water drum M of the boiler. The installation shown includes g and the other superheater and its associated parts in broken or dotted lines.

In order to maintain the temperature 'of'the steam delivered by the superheater installation constant notwithstanding variation in the load,

on the boiler, and consequent variation in the firing, there is associated with each of the crossover connections I9, 2|, 23 or 2B; 22, 24,

adesuperheating apparatus

25 or 26 respectively. Each desuperheater is of the non-contact type, and valve means control the proportion of steam which flows through the desuperheater and the'otherwise direct path from a primary to a secondary superheater. Conveniently two

valves

2T, 29 or 28,30, which may be of the butterfly type, are employed in each cross-over, one valve 21 or '28 controlling the direct path between the superheater sections and the other valve 29 or 30 controlling the path through the desuperheater. These valves are controlled by thermostats 3|, 32 in the outlets I'I, I8 for superheated steam from the respective secondary sections of the superheater.

The desuperheating apparatus shown is of known construction and comprises a drum or vessel having a lower portion constituting a hi chambered header and tube plate, inverted U- loop tubes being connected to the header portion of' the desuperheater. One header chamber is connected to the portion I 9 or 20 of the cross-over leading from the primary superheater and the other is connected to the portion 23' or 24 leading to the secondary superheater. To the drum or vessel above the tube plate wateris supplied by a

connection

33 or 34 from the bottom boiler drum I4 and the desuperheater is disposed in such a manner that with the water level therein coincident with the water level in the top boiler drum I3 the U-shaped heat exchange tubes in the drum are submerged. Below the normal water level a circulating

pipe

35 or 36 connects the water space of the desuperheater with the water space of the upper boiler drum I3. From the top of the de-' superheater a connection 31 or 38 is provided for delivering steam generated in the desuperheater to the steam space of the upper drum I3 of the boiler.

By arranging the desuperheater and its connections to the boiler drums in the manner described, Water will circulate from the drum I4, through heater will riseQdue to the'presence of steamin the body of water in the desuperheater rendering such water less dense than the boiler water. Consequently, as shown in Fig. 3, the pipe-35B by which waterreturns to the boiler drum I3 may By thus 2,035,763 a 1 p i z take off from the desuperheater casing at a point above the normal water level in the boiler but below the level to which water rises in the desuperheater when the latter is in operation. Thus circulation of boiler water through the desuperheater will be maintained when the desuperheater is in operation, but not take place when the desuperheater is not working.

It will be appreciated that on a rise in temperature of the steam delivered by a secondary super-heater the thermostatically controlled valves will operate to pass a greater proportion of the steam from the associated primary superheater through the desuperheater, and thus reduce the temperature of the steam entering the secondary section of the superheater, so that a reduction in 'the final steam temperature at that secondary section of the superheater will be obtained. Thus excessive temperature either in the secondary section of the superheater or at the prime mover will be prevented. As already indicated the cross-connection from the primary superheater at one side of the boiler to the-secondary superheater atthe other side of the boiler ensures that the two secondary superheaters deliver steam at the same or substantially the same temperature, as should the boiler be fired more heavily on one side than on'the other the increase in the primary steam temperature at the one side of the boiler will be. oiTset by the reduction in the'superheater in the secondary section on the other side of the boiler, and the lower, superheat in' the other primary section will be compensated forby the increased superheat in its associated secondary section.

- The principal difference between the forms of the invention illustrated in Figs.4 to '6 from theform shown in Figs. 1 and 2 lies in the fact that the superheater sections on'either'side of' the boiler are not separated from each other in' the direction of 'gas'travel, but are at the same distance from the furnace, the tubular elements of one being interleaved with those of the other.

The inlet headers in these figures'are again designated by' thereference numerals I and Z, and the elements to which they deliver the saturated steam are shown at 5 and 6 respectively. The outlet ends of these elements are connected respectively to the intermediate headers 50 and 5|. It is possible with this arrangement to make the header to which each first section elements deliver steam continuous and unitary with the inlet header for'the corresponding second section and this is done in the form shown, headers 50 and SI extending across the boiler setting from side to side and serving as outlet headers for the first sections and inlet headers for the second sections. H 7

The'straight tube lengths of adjacent loops may be abreast of each other so all of them are in alinement transversely of the boiler setting as in Fig. 5, or they may be staggered as in Fig. 6.

Although certain constructional details have been referred to herein the invention is not necessarily restricted .to all the details of construction describedas some variations might be made without departing from the invention.

What I claim is:

1. A method of compensating for the effect on two steam superheaters arranged side by side across a boiler, and operating in parallel, of differences in firing across the boiler, consisting in dividing each superheater 'into a primary sectionand a secondary or final section and heating the primary section of one superheater and the secondary or final section of the other superheater by the products of the combustion of fuel at one side of the boiler and heating the remaining sections of the two superheaters by the products of combustion of fuel at the other side of the boiler.

2. A method of compensating for the effect on two steam superheaters arranged side by side across a boiler, and operating in parallel, of differences in firing across the boiler, and of controlling the final temperature of steam delivered by such superheating installation, consisting in dividing each superheater into a primary section and a secondary or final section, delivering steam from a primary section of a superheater into its associated secondary or final section either directly or through a desuperheater individual to such superheater, heating the primary section of one superheater and the secondary or final section of the other superheater by the products of the combustion of fuel at one side of the boiler, heating the remaining sections of the two superheaters by the products of combustion of fuel at the other side of the boiler, and regulating automatically in each superheater the proportions of steam flowing through the direct path and desuperheater, respectively, by thermostatically controlled means responsive to variations in the temperature of the steam delivered by the final section of such superheater.

3. A steam superheating installation comprising two superheaters arranged side by side across a boiler and operating in parallel, each superheater having a primary section and. a secondary or final section connected in series, wherein the secondary or final section of each of the pair of superheaters is disposed at the side of the boiler opposite to that at which its associated primary section is located, for the purpose set forth.

4.-A steam superheating installation according to claim 3, the secondary sections being at a'difierent distance from the furnace as regards gas fi'ow than the two primary sections.

5. A steam superheating installation according to claim 3, the secondary sections being more remote from the furnace as regards gas flow than the two primary sections.

6. A steam superheating installation according to claim 3, the secondary and the primary sections all being at substantially the same distance from the furnace as regards gas flow.

'7. A steam superheating installation according to claim 3, the secondary and the primary sections all being at substantially the same distance from the furnace as regards gas flow, the elements of each primary section alternating with those of the secondary section of the other superheater.

ERIC A. ROBINSON.