US2366718A - Vapor generator - Google Patents

Description

Jan. 9, 1945, M. FRlscH VAPOR GENERATOR Filed Nov. 17, 1941 2 Sheets-Sheet 2 ATTORNEY Patented Jan'. 9, 1945 Martin Frisch, New York, N. Y.,

ter Wheeler Corporation,

assigner to Fos- New York, N. Y., a

corporation of New York Application November 17,` 1941, Serial No. 419,388

6 Claims. (Cl. 122-478) This invention relates to vapor generators and more particularly pertains to apparatus for generating and superheating steam.

The invention provides a multiple furnace.

superheating steam generator of novel and compact arrangement with which superheat control at all loads on the generator is obtained.4

The features and advantages which characterize the invention will be understood from the following description considered in connection with the accompanying drawings forming a part thereof, and in which:

Fig. 1 is a vertical sectional view of a steam generator embodying the invention;

Fig. 2 is a horizontal sectional view taken on line 2-2 of Fig. 1;

Fig. 3 is a horizontal sectional view taken on line 3-3 of Fig. 1;

Fig. 4 is a horizontal sectional view taken on line 4-4 of Fig. 1, and

Fig. 5 is a horizontal sectional view taken on line 5-5 of Fig. 1.

Like characters ofreference refer to the same parts throughout the several views.

Referring to the drawings the steam generator illustrated has substantially vertical refractory sidewalls II and I2, a rear side wall I3, a front side wall, not shown, an end wall having roof portions I4 and I5 and an end wall having furnace bottom portions 3B and 31. Adjacent one tition walls 22 and 23 respectively denne p the outer boundaries of the furnaces. The furnace side of the wall 22 is lined by water wall tubes 3| which extend from the drum I6 to a lower header 32. Opposite sides of the partition 30 are lined, respectively, by water wall tubes 33 and 34 whichextend from the drum I6 across the innerl surface of the roof portion I4 and are connected at their lower ends to a header 35.. The front and rear Walls of the furnaces are similarly lined. with water wall tubes, although they are not shown,

side of the roof portion I4 is a steam and water drum I6. Connected to this drum is a bank of substantially vertical steam generating tubes I1 which extend downwardly adjacent and parallel to the'side wall II and-at their lower ends are connected to a drum I8. 'I'he tubes are disposed in a gas pass I9 which is defined by the wall I I on one side of the .tube bank and a vertical baille wall 2U on the other side. This pass I9 communicates at its upper end with an outlet flue 2|.

spaced inwardly a short distance from the ver-f tical baiile 20 is a vertical partition wall 22.

Adjacent the opposite side of the `setting is a corresponding vertical partition wall 23 which is disposed inwardly of the side wall I2 and forms therewith a vertical gas pass 24 which communicates at its upper end with a flue gas outlet 25. Within the setting and between the partition walls 22 and 23 are two separate firnaces 26 and 21 arranged tooperate in parallel, and which are tired, respectively, by the fuel burner 28 disposed in the roof portion` I4, and by the fuel burner 29 disposed in the roof portion I5. ,A vertical partltlon wall 30 separates the two furnaces and forms the inner boundary thereof, While the par..

and the several tubel groups described and referred to are suitably connected into the circulatory system of the unit. Inwardly inclined furnace bottom wall portions 3B and 31, vthe upper endsl of which are spaced from the lower ends of the partition walls 22 and 23 respectively, provide the furnaces with hopper bottoms. A soot hopper 38 is disposed directly below the gas pass or heating chamber I9, while a similar soot hopper 39 is disposed directly below the gas pass or heating chamber 24. The side walls II and I2 of the setting are respectively provided with a plurality of lancing -doors 40 and 4I.

In the form of the invention illustrated, a combination radiant and convection superheater is utilized and is so arranged and disposed that it is exposed to the products of combustion produced in one furnace only, i. e., the furnace 21, which `may be referred to as the superheater furnace. The furnace side of the partition wall 23, is lined with vertical radiant heat superheater tubes 42 and 43 which are arranged as shown in Fig. 3, and which form a continuous panel or section of radiant heat absorbing surface except at 46 where the tubes are spread apart, as shown more particularly in Fig. 4, to form a furnace gas outlet passage between the Vbottom of the partiv l23 where they pass through the partition and are formed into a plurality of return bend loops of a convection superheater section 45 which is vertically disposed in the gas pass 24 throughwhich gases flow from the furnace 21 to the outlet flue 25. superheater section and the tubes 45 oi' the convection section, which are arranged for series l flQW 0f Steam therethrough, are continuous with The tubes 43 of the radiant heat heater tubes are formed into a partial loop to provide for expansion of the tubes.

In operation, the gases produced inthe furnace 26, which may be called the saturated steam furnace, flow downwardly through the furnace and through gas outlet passage 48 which is similar to the g'as outlet passage 46, and upwardly over the steam generating tubes I1 to the outlet flue 2l. Saturated steam is conducted from the upper drum I6 and flows downwardly through the tubes 42 and upwardly through the tubes 43 mainly in radiant heat exchange relationship with the gases produced in superheater furnace 21. From this radiant heat absorbing section of the superheater, the steam flows through the loop elements of the convection superheater section 45 in convection heat exchange relationship with the gases flowing from the furnace 21 through the gas pass 24 to the flue outlet 25. The quantity of steam produced will be determined largely by the rate at which the furnace 26 is fired, although some steam will be generated in water walls of the furnace 21. Inasmuch as the gases produced in the saturated steam furnace 26 do not flow in heat exchange rela'- tionship with the superheater, the degree to which the steam is superheated will be determined by the degree to which the superheater furnace 21 is fired. Furnace 21 ymay be fired to obtain the superheat temperature desired at any load on the generator, or it may be fired to obtain and to maintain a substantially constant degree of superheat at all loads on the generator. The superheating characteristics of the combination the lancing doors 40 and 4I. This is, particularly desirable when certain types of fuel, such as highA volatile coals are employed, because the ash of such fuel frequently tends to become soft and to adhere to the surface of the tubes in undesirable quantities at relatively low temperatures.

It will be understood that changes may be made in the form, location and relative arrangement of the several parts of the steam generator disclosed herein without departing from the principles of the invention. Consequently, the invention is not to be limited excepting by the scope of the appended claims.

What is claimed is:

1. VVapor generating apparatus comprising a setting, means providing two separate furnaces in the setting separated by an imperforate wall,

means for firing each furnace disposed at one end of the setting, the setting having a gas cutlet for each furnace, each furnace having a gas outlet opening in a side wall thereof other than the wall separating the furnaces and adjacent the end of the setting opposite the end at which said firing means are disposed, each of said firing means being arranged to direct its gases of combustion in a substantially vertical path of iiow 'toward the gas outlet opening of the furnace with which it is associated, means forming a gas passage adjacent an outer wall of each furnace and radiant heat and convection superheater employed, contribute to the maintenance of a constant superheat temperature.

With this arrangement, since the superheater sections are entirely shielded from the gases leaving one of the furnaces, the steam generator may be started up by firing that furnace only, thus eliminating any necessity for flooding the superheater during starting up periods. This considerably shortens the time ordinarily required to bring the unit onto the line. Also if a feed water heater were out of service, a constant steam temperature can be maintained without the use of a by-pass or any other means of superheat control except for the differential firing provided.

The elimination of intermediate header connections between the radiant and convection sections of the superheater, simplifies and reduces the cost of construction of the superheater and reduces the pressure drop, although intermediate headers may be employed if desired. The relatively large amount 'of furnace cooling surface possible with the multiple furnace arrangement,

and thevertically downward ring of the fuel burners, results in low temperatures in the ash rejecting zones of the furnaces and thus tends to insure dry ash removal.

With the bank of steam generating tubes and extending along that furnace, the gas passages being oppositely disposed with the furnaces therebetween, each gas passage being in communication with the gas outlet of the setting for the furnace adjacent thereto and the gas outlet opening for said furnace and having one dimension which is less than the corresponding Adimension of the adjacent furnace, vapor generating surface in one gas passage, and vapor superheating surface in the other gas passage.

2.-Vapor generating apparatus comprising a setting, means' providing two separate furnaces in the setting separated by an imperforate wall. means for firing each furnace disposed at one outlet opening in a side wall thereof other than the wall separating the furnaces and adjacent the end of the setting opposite the end at which I said firing means are disposed, each of said firing means being arranged to direct its gases of combustion in 'a substantially vertical path of flow toward the gas' outlet opening of the furnace with which it is associated, means forming a gas passage adjacent an outer wall of each furnace and extending along that furnace, the gas passages being oppositely disposed with the furnaces therebetween, each gas passage being in communica-` tion with the gas outlet of the setting for the furnace adjacent thereto and the gas outlet opening for said furnace and having one dimen sion which is less than the corresponding dimension of., the adjacent furnace, vapor generating surface in one gas passage, and a superheater having a part at least within the other gas pasf setting, means providing two separate furnaces in the setting separated by an imperforate wall,

means for firing each furnace -disposed at one end of the setting, the setting having a gas outlet for each furnace, each furnace having a gas outlet opening in a side wall thereof other than the wall separating the furnaces and adjacent the end of the 'setting oppositefthe end at-which said ring means are disposed, each of said firing means being arranged to direct its gases of combustion in a substantially vertical path of flow toward the gas outlet opening of the furnace with which it is associated, means forming a gas passage adjacent an outer wall'of each furnace and extending along that furnace, thefgas passages being oppositely disposed with the furnaces said side wall of each furnace and extending along that furnace, the gas passages being oppositely disposed with the furnaces therebetween,

therebetween, each gas passage being in communication with the gas outlet of the setting for the furnace adjacent thereto and .the gas outlet opening for said furnace and having one dimension which -is less than the corresponding dimension of the adjacent furnace, vapor generating surface in one gas passage, and a superheater having a part within the othergas passage and another part in the furnace adjacent said passage and along a wall of said furnace.

4. Vapor generating apparatus comprising a setting, means providing two separate furnaces in the setting separated by an imperforate wall, burner means for firing each furnace disposed at the top thereof, the setting having a gas outlet at the top thereof for each furnace, each furnace having a gas outlet opening at the bottom of a side wall thereof other than the wall separating the furnaces, each of the burners being arranged to direct its gases of combustion in a substantially vertical path of flow toward the gas outlet opening of the furnace with which itis associated,Y means forming a gas passage adjacent said side wall of each furnace and extending falong that furnace, the gas passages being oppositely disposed with the furnaces therebetween, each gas passage being in communication with the gas outlet of the setting for the furnace adjacent thereto and the gas outlet opening for said furnace and having one dimension which is less than the corresponding dimension of the adjacent furnace, vapor generating surface in one gas passage, and vapor superheating surface in the other gas passage.

5. Vapor generating apparatus comprising a setting, means providing two separate furnaces in the setting separated by an imperforate wall, burner means for ring each furnace disposed at the top thereof, the setting having a gas outlet at the top thereof for each furnace, each furnace having a gas outlet opening at the bottom of a side wall thereof other than the Wall separating the furnaces, eachy of the burners being arranged to direct its gases of combustion in a substantially vertical path of now toward the gas outlet opening of the furnace with which it is associated, means forming a. gas Passage adjacent each gas passage being in communication with the gas outlet of the setting for the furnace adjacent thereto and the gas outlet opening for said furnace and having one dimension which is lessthan the corresponding dimension of the adjacent furnace, vapor generating tubes on the furnace side of said side wall other than the wall separating the furnaces, said tubes extending over the gas outlet opening and spaced apart at said opening to permit flow of gases into the passage, vapor generating surface in one gas passage, and a superheater within the setting having a part within the other gas passage and another part in the furnace adjacent said passage and along a wall of said furnace.

6. Vapor generating apparatus comprising a setting, means providing two separate furnaces in the setting separated by an imperforate wall, burner means for firing each furnace disposed at the top thereof, the setting having a gas outlet at the top thereof for each furnace, each furnace having a'gas outlet opening at the bottom of a side wall thereof other than the wall separating the furnaces, each of the burners being arranged to direct its gases of combustion in a substantially vertical path of ow toward the gas outlet opening of the furnace with which it is associated, means forming a gas passage adjacent said side wall of each furnace and extending along that furnace, the gas passages being oppositely disposed with the furnaces therebetween, each gas passage being in communication with the gas outlet of the setting for the furnace adjacent thereto and the gas outlet opening for said furnace and having one dimension which is less than the corresponding dimension of the adjacent furnace, vapor generating tubes on the furnace side of said side wall other than the wall separating the furnaces, the tubes on the one side wall of one of the furnaces being spaced apart, said tubes extending over the gas outlet opening and spaced apart at said opening to permit flow of gases into the passage, a superheater in the setting having tubes disposed in the spaces between the spaced vapor generating tubes on said side wall of said one furnace and extending within the passage adjacent the said side wall thereof, and vapor generating surface in the settingin the passage receiving gases from the other furnace.

MARTIN FRISCH.

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