US1910843A - High pressure water tube steam generator - Google Patents

Description

y 1933- A. LIEBERHERR 1,910,843

HIGH PRESSURE WATER TUBE STEAM GENERATOR Filed Dec. 2, 1930 UNITED STATES ART U LIEBERHER E WINTERTHUR, SWITZERLAND, ASSIGNOR To THE mm Patented May 23, 1933 PATENT OFFICE OF SULZER FREE/ES socIETE ANONYME, or WINTERTHUIRSWITZERLAND HIGH rnEssuRE WATER Application;fi1edDeceinber2, 1930, Serial No.

i This, invention relates to high pressure water tube steam generators, and has for its object .to overcomethe pulsations to which such generators are at present liable and which are caused when the tube becomes filled with steam whichsuddenly escapes "so thatuthe consequent rapid inflow of water reduces the effective super-heating area. Such pulsations are further increased by the geyser action causedby a considerable length of tube being suddenlyyfilled with steam which prevents the'flow of'feed water, thisaction, as is well known, being stronger the lower the working pressure and tge greaterthelength of the tube to be heat- 6 l 1 i 1 l According to thisiinvention fluctuations in the evaporation ofthe steam due to unstable equilibrium of flow are preventedby introducing the main portion of the workingfmedium atthe inletend of a high pressurexwater tube steam generator whence it flows without being throttled to the outlet end ofthertube and is there discharged in the form of dry steam, an additional minor quantity of working medium being constantly introduced intothe system of tubes at at least one point between .the'inlet and outlet ends,: preferably through inlet-s of narrow cross-section. Preferably someiof constrictedpassage so thatthe amount of medium introduced at each individual point can be regulated at will.

This arrangement enables the pulsations which would otherwise occur in the steam generator to'be clamped to a considerable extent, as the regulation which automatical- 1y takes place at each fall ofpressure is effected in a steady and regular manner which will notinterfere with the super-heating. A construction according to this invention is diagrammatically illustrated by. way of example in the accompanying drawing, inwhic TuB sTE M GENERATOR 499,454, and in Switzerland December aisza. I

Figurel is a vertical section, i

Figure? shows on an enlarged a throttlingpointin section, a l

Figure shows diagrammatically a modification of the arrangement illustrated in Figure l, 1

Figures 4 and 5 are sections through a pipe coil showing the zone withinwhich water "is converted intosteam; and y i Figure 6 shows the same zone of a steam gene ator constructediiin accordance with the detailshown in Figure 2. l a w The high pressure steam generator illustrated comprisesfa coiled pipe lenclosed in acasing, for example, of masonry 2 or other heat-insulating material. Any suitable source of'heat maybeused, such for example a liquid, gaseous or pulverizediuel, in the example diagrammatically shown a burner 3 being employed supplied through a pipe/l. The air to support combustion is "admitted into the burner through a pipe "'5 so that it is mixed with the fuel and passes in the form of a combustible mixture into the combustion chamber Got the steam genm erator. a i i A The burnt gases areeither dischargeddirect through the chimney 7 or passed through a feedwater heater or other de- Vice by which their waste heat is utilized. A feedwaterpump 8, shown as a centrifugal pump supplied with liquid through the pipe 9, delivers feed water through the pipe 10 into the steamgeneratingcoil 1, the liquid delivered being regulated by a device 11 interposedbetween the pump andthe supply pipe 10. Thesteam generatedis delivered tothe points of consumption through thepipe12. l Q For introducing additional feed waterfa pipe 14 is provided which is in communication with theeteam generator coil 1 and provided with a-throttling device 15 by which the quantity fO liquid introduced through the pipe 14: can be regulated. The adjustment of the cross-sectional areajof the pipe may be effected in any way, asfor example, by means of a perforated disc 16 shown in Figure 2. i g

Figure 3 shows an alternative arrangement in which in addition to the feed water introduced through the normal inlet 17 small quantities of feed water are introduced into the pipe coil 1 through additional supply pipes 1& each provided with a throttling device as shown.

Figure 4 shows in development part of a pipe coil in which the working medium is ina liquid, state up to the point a after which it passes. into a. state of evaporation. Pulsations may cause the feed water to shoot forward or advance up to a new limit I) (Figure 5) which would alter the boundary between the state of liquid and vapour, thus reducing the effective length of the pipe coil capable of being used for superheating.

According to the present invention these pulsations are prevented or damped by supplying the feed medium in small quantities,

' one such quantity being introduced at the point 0 in addition to the main feed water introduced at 17. g a

As will be seen from Figure 6, which represents a development of that part of the steam generator enclosed withinthe circle in Figure 1, the worln'ng of the steam generator takes place in the following manner.

When, owing to a rapid discharge of steam, pressure is reduced, an abnormal quantity of feed water will flow through the pipe and will retard the generation of steam to a corresponding extent. In this way the pipe friction will be again increased owing to the presence of more water in the pipeand the supply through the branch pipe will be reduced so that the generation of steam will again increase but inrush of water such as is indicated at Figure 5 will be prevented or at least reduced.

The introduction of small quantities of feed water, which in certain circumstances may be very small quantities, takes place at or about the boundary between the steam and water zones- Owing to thepulsations being avoided or reduced, loss ofsuperheat- 'ing area is obviated and consequently the boundary between the water and steam zones and hence the point at which steam generation and superheating begin are maintained substantially constant.

It will be understood that the source of heat may be other than that illustrated and if desired could be disposed in the upper part of the generator casing whether the feed water is supplied from the top or from the bottom. Any desired number of pipe coils can be used connected together in par allel or in series in-accordance with the output required and feed water heaters may be arranged in any well known manner without departing from the invention.

I claim:

1. In a high pressure water tube steam generator, in combination means for introducing feed water at the inlet end ofthe tube system'through which it flows without being throttled to the outlet where it is discharged as steam and means for constantly and continuously introducing an additional quantity of feed medium into said tube system through narrow invariable transverse sections at at least one point between the inlet and outlet end oi: said tube, additional medium being introduced in the form of a jet compounded with the main body of working medium, whereby the supply of additional water is controlled in accordance with the varying density and state of matter of the main body of working medium. v

2. In a high pressure water tube steam generator, in combinationmeans for introducing feed water at the inlet end of the tube system through which it flows without being throttled to the outlet where it is H discharged as steam and a pipe of reduced fixed cross-section for continuously introducing an additional'quantity of feed medium into said tube system at a point between the inlet and outlet end of said tube, additional medium being introduced in the form or" a jet compounded with the main body of working medium, whereby the supply of additional water is controlled in accordance with the varying density and state of matter tube system through which it flows without being throttled to the outlet where it is discharged as steam and pipes of reduced fixed cross-section for continuously introducing an additional quantity of feed medium into said tube system at points between the inlet and outlet end. of said tube, addi- 1 tional medium being introduced in the form of a jet compounded with the main body of working medium, whereby the supply of additional water is controlled in accordance with the varying density and state of matter of the main body of working medium.

4. In a high pressure water tube steam generator, in combination means for introducing feed water at the inlet end of the.

tube. system through which it flows without being throttled to the outlet where it is discharged as steam and means for continuously introducing an additional quantity of feed medium into said tube system through a constricted, fixed-size passage near a point where" the working medium is converted from a liquid into a vaporous state, additional medium being lntroduced in the form of a jet compounded with the main body orlwork-Vv ing medium, whereby the supply of addibil a erators of the kind in which the main quantity of feed medium is-introduced at the in let end of the tubes through which it flows without being throttled to the outlet end, Where it is discharged as steam, by means of an additional quantity of feed medium introduced into the tube system between the inlet and outlet ends of the tubes, comprising introducing constantly the additional quantity of feed medium through passages

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