US2108135A - Steam generator - Google Patents

Description

J. J. NELIS STEAM GENERATOR Feb. 15, 1938.

Filed May 15, 1935 OO o u oo ,oooo u Patented Feb. 15, 1938 UNITED STATES PATENT OFFICE STEAM GENERATOR Application May 15, 1935, Serial No. 21,519

4 Claims.

This invention relates to steam generators. More particularly, the invention pertains to steam generators having separately red superheaters and other heat utilizing and heat recovery devices.

The invention provides an improved arrangement and combination of steam generating, superheating, and other heating apparatus which makes possible a high degree of operating eiliciency, high fuel economy and great flexibility of control under fluctuating demands with respect to nal steam temperatures and pressures, and which is primarily adapted to marine use and the severe operating conditions and requirements on shipboard from the standpoint of both safety and economy.

In recent yearsthe use of greatly increased steam pressures and temperatures has become common practice in the marine eld, and furnace A and boiler efficiencies closely approximate those of the modern steam plants on land. Due to this development, however, and to the demand for increased pressures and superheated steam of high temperatures, a particular 'problem has arisen with respect to turbine operation when maneuvering the present day turbine driven ship at sea and taking it in and out of port. When going astern or in any maneuver requiring a reversal of the forward drive of the ship, the re- 30 versing wheel of a marine type reversing turbine can not be subjected to the same high steam pressures and temperatures as may properly be employed on the normal forward drive, without the possibility of serious damage such as pitting or stripping of the blades, since the reversing side of marine turbines is not capable of withstanding such severe operating conditions. The need, therefore, of an economical and ready means for at certain times reducing and controllingthe temperature of the superheated steam on shipboard .is apparent, and to this end my invention is directed.

One method used in marine practice in an effort to meet this problem consists in injecting streams of water into the superheated steam line Although the temperature of the to the turbine. superheated steam is thus reduced it has the disadvantage, that unless carefully controlled, of being dangerous since the introduction of jets or streams of water into the highly heated steam may-cause slugs of water to enter and injure the turbine.

The object of the present invention is to provide a steam generator having a superheater combined therewith in the setting in such manner that superheat control is readily obtainable regardless of boiler operation within the available space requirements in marine use.

The various particular features of novelty which characterize the invention are pointed out 5 in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, reference may be had to the accompanying drawing in which:

Fig. 1 is a vertical sectional view of steam l0 generating apparatus embodying the invention, taken on line I-I of Fig. 2, and

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

Referring to the drawing, reference character 15 Ill designates the setting of a steam generator having a furnace II, upper and lower drums I2 and I3 respectively, having a bank of steam generating tubes I4 extending therebetween, and water wall tubes I5. A plurality of burners I6 of 20 suitable type having means for controlling the intensity of'ring are disposed-in one or more of the walls of the furnace II. Bailles I1 and I8 provide three passes for the furnace gases over the steam generating tubes I4. The wall I9 of 25 the setting has an opening 2|) in its upper portion, through which the gases flow from the third gas pass into the flue 2l having an economizer 22 and an air heater 23 disposed therein.

A vertically extending wall 24 which is spaced 30 from wall I9 and in parallel relationship therewith provides a superheater compartment 25 having a superheater 26 located in its upper portion below the passage 20 and connected with the steam space of the upper drum I2 by a conduit 2l. 35 A burner 28 of any suitable type having means for readily. controlling the intensity of firing ls disposed in the lower portion of one of the walls forming the superheater compartment 25 which connects with the lower end of the ue 2I. If 40 desired, a plurality of such burners may be so disposed. J

With this arrangement it will be perceived that the superheater is separately fired and the degree of superheat may readily be controlled by control- 45 ling the operation of the superheater burner 28 independently of the operation or ilring of the boiler. In other words, the degree of superheat obtainable may be varied from zero to maximum entirely independently of steam generation. 50 Moreover, the gases leaving the superheater compartment after having passed over the superheater, enter the boiler ilue 2l and are further cooled by their passage over the economlzer and air heater 22 and 23 respectively, thereby materially contributing to the overall efficiency and economy of the unit. The superheater is preferably placed in the same general steel casing structure that encloses the boiler.

With steam generators embodying the invention, a ready and dependable control of the degree of superheat is at all times available, and at the same time a high degree of operating efciency is maintained. My invention has a special application to marine use, where due to maneuvering in port, or emergency stoppage, and reversing at sea, a 10W degree of superheat becomes essential because of temperature limitations with respect to turbine operation under the above conditions.

It will be understood, however, that other types of steam generators than that disclosed herein may be utilized without departing from the principles of the invention which is not to be limited except by the scope of the appended claims.

Having thus described my invention, what I claim is:

1. A steam generating plant comprising a setting, a furnace therein, a steam generator in the setting, means for firing the furnace, a superheater compartment in the setting, a superheater in the compartment and connected to the steam generator, separate means for firing the superheater, said compartment being arranged to shield the superheater from heat radiated from said furnace and to prevent gases; from said furnace from contacting the tubes of the superheater, and a iiue connecting with the setting and beingso arranged relative to the furnace and the superheater compartment that the gases from said furnace pass to the ue without contacting the superheater and that the gases from the superheater compartmentV pass vto the flue without contacting the steam generator, the superheater compartment occupying a minor portion of the setting, the arrangement being such that by control of the means for firing the superheater alone any desired degree of superheat from zero to maximum may be obtained.

2. A steam generating plant comprising a setting, a vertically extending partition in the setting forming a steam generating section and a superheating section, a steam generator in the steam generating section, a superheater in the superheating section and connected to the steam generator, separately controlled means for iring each section, and gas outlets from each section connected to a common oiftake flue, the steam generator and the superheater being disposed ahead of the point of junction of the gas outlets from said sections with the common offtake ue with respect to the direction of ow of the gases passing from said sections, the arrangement being such that by control of the means for tiring the superheater section alone any desired degree of superhe'at from zero to maximum may be obtained.

3. A steam generating plant comprising a setting, a furnace therein. a steam generator in the setting, a fuel burner for ring the furnace, a superheater compartment in the setting, a superheater disposed wholly in the compartment and connected to the steam generator, a-fuel burner for firing the superheater, said compartment being arranged to shield the superheater from heat radiated from said furnace and to prevent gases from said furnace from contacting the tubes of the superheater, and a flue connecting with the setting and being so arranged relative to the furnace and the superheater compartment that the gases from said furnace pass to the flue Without contacting the superheater and that the gases from the superheater compartment pass to the flue Without contacting the steam generator, the superheater compartment occupying a minor portion of the setting, the arrangement being such that by control of the fuel burner for iiring the superheater. alone' any -desired degree of superheat from `zero to maximum may'be obtained.

'4. A steamgenerating plant comprising a setting, a vertically extending partition in the setting forming a steam generating section and a superheating section, a steam generator in the steam generating section, a superheater in the superheating section and connected to the steam generator, separately controlled fuel burners for firing each section, and gas outlets from each section connected to a common oitake flue, the steam generator and the 'superheater being disposed ahead of the point of junction of the gas outlets from said section with the common ofi'- take flue with respect to the direction of iiow of the gases passing from said sections, the arrangement being such that by control of the fuel burner for firing the superheater section alone any desired degree of superheat from zero to maximum may be obtained.

JOSEPH J. NELIS.

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