US1746158A - Heating device for high-pressure steam generators - Google Patents

Description

F 3D. s Lb FLi-il 1,

HEATING DEVICE FOR HIGH PRESSURE STEAM GENERATORS Filed Sept. 24, 19z5 A Zlarng.

- Patented Fe 4,1930

STEPHAN IlfiFFLER, OF CHARLOTTENBURG, NEAR BERLIN, GERMANY HEATING DEVICE FOR HIGH-PRESSIl'RE STEAM GENERATORS Application -fl1ed-Septe'mb er"24, 1925, Serial No. 58,409, and in Austria September 29, 1924.

My invention relates to a heating device comprising, in general, a furnace, such as a grate furnace, an oil. furnace, a dust-coal furnace, or the like, flues through which the 5 hot furnace gases are caused to flow, and

coiled pipes or equivalent members which are located in said flues and through which the fluid to be heated, such as steam or Water or a mixture of both, is conducted.

are subdivided into a plurality of elements, as for instance into individual coiled pipes which are connected up in parallel so that also the steam etc., is subdivided into a plurality' of currents streaming in parallel through the individual coils.- The subdivision of the heating members and the arrangement of the heating elements in the current or currents of the heating gas is-effected in such a way. that theheating effect is equally strong in all elements independent of the-intensity of the fire in the furnace, as well as of the absolute the gas tenh.

perature.

The coiled pipes, or the separate individual elementsof which they are composed, are so disposed that they form, partly or wholly, passages or flues for the furnace gases whereby it is rendered possible to dispense with walls of masonry or other refractory material which are subjected to great wear and tear in that they are exposed to the intense heat of the fire-gases but are not cooled sufliciently. In view of these deficiencies of the known heating devices for steam etc., my improved one is by far more reliable and the costs of erection, as well as of maintenance, are considerably less, and as the weight of heating devices of the improved kind is by far lower they are suited particularly for portable. plants, as on locomotives and in ships. Another advantage; resides therein that the improved heating devices'becomegoperative in a considerably shorter time in that firing-up proceeds far more quickly.v

My invention is illustrated dia-grammat ically and'by way of example in the accompanying drawing in which Figure 1 is a vertical axial section through a heating device 507 designed according to this invention; and

The heating members for the steam.etc.,

rounding Wall of masonry or the like.- The tubular space, with the several pipepor- Figure 2 is a plan of the two telescopically arranged coils shownin Fig. 1.

Referring to Figurel, ldenotes the uppermost portion of a furnace of any suitable kindfrom which the hot gases pass upwards in the direction indicated by the arrow .11. 2 denotes superposed coiled pipes which form, in their entirety, .two telescopically arranged sets forming a central passage or flue in which the fire gases stream upwards, and a tubular passage or flue in which they stream downwards whereafter they flow again upwards through anothertubular passage or flue formed between the outer coil and the sur- 5 6 individual convolutions 'of the "individual coils contact with each other, as do 'also the superposed sets, so that the hot gases are compelled to -flow through the entire length of each of the consecutivepassages. The exhausted gases leave the heating device at 6.

Every individual pipe is so bent as to form some inner convolutions d and some outer convolutions d (Fig. 2) which are connected with each other by a semicircular portion of tube 03 in such a manner that the direction of flow in the convolutions d is counter'to the. direction of flow in the convolutionsd as indicated by the arrows in Fig.2. The water or steam is supplied through a tube 4:, Fig. 1, into a distributing casing 3 from which it is distributed into the pipe portions 0! that conduct the respective fluid to and into the convolutions (i The heated water or the superheated steam. or whatever the fluid may be, leaves'the coils d through the tube-portions d Fig. 2, and gets into a collecting casing 6 from which it is conducted away through another pipe (not shown) to the place of use.

A preferred constructional form of the dis tributing vessel 3 is that in which the supply 'pipe l extends down into. said casing to near the bottom thereof, and the dimension of the bore of this casing is ,such that a tubular space is formed between the inner surface of said bore and the outer surface of the tube 4, and that the holes connecting this.

tions d increase in diameter from the lower- .or the like), the losses of heat by radiation are reduced toa minimum.

- The hot gases and the water or steam flow alternately in the same direction andin opposite directions, and the sectional area of the gas passages is so determined that the velocity of the heating gases is practically constant in spite of the decrease of volume resulting from the .fall of their temperature.

The waste gases escaping at b may be utilized and exhausted in known manner by any known device for preheating the combustion air to be introduced into the furnace, and this air, prior to being pre-heated, may be utilized forv cooling the masonry wall or the like enclosing the coiled pipes.

I wish it to be understood that the drawing shows the improved heating device merely diagrammatically. It will be obvious to every expert that the device can be so designed that it is easilypossible to separate the coils from one another and to remove them vertically out of the space in which they are housed, also to re-insert them into that space from above; and it is also possible to arrange the distributing casing and the collecting casing upon or above the to and to connect them by vertical pipes with the coils below them. Or lateral apertures may be provided in the surrounding wall through which the coils 'may be removed and re-inserted, and doors or other closing means'may be provided for said apertures which latter aflord also access to the various surfaces requiring cleansing from time to time.

In the constructional form shown in Fig. 1,

every convolution supports all other convolutions located above it, but the arrangement of the convolutions and of the members 3 and 6 relatively to one another may also be such that these members carry a part of the weight of the convolutions. The lowermost convolutions (or all, as the case maybe) may be carried by annular rows of supports 5, Fig. 1, through the interstices of which the firegases pass, as indicated by the lower arrows inthe neighbourhood of the numerals 5.

The heating of water in the coiled pipes,-

or the superheatingof steam therein, is very uniform. The temperatures which every coil is exposed to at the respective inner flue,

of the device and outer flue are different, it is true, but the respective degrees are summed up in such a manner that the sum is the same at all convolutions. This will become evident by the simple consideration that the fire-gases are being cooled down according to the length of the way they have covered. Taking as an example the uppermost convolutions d, i. e. at the top of the column of convolutions, where the gases pass from the central flue to the first tubular flue. Here the temperature on the inner face of those convolutions and on the outer face thereof is nearly the same, as the ases have transmitted only little heat on t eir way from the one flue to the other. Now let us consider the lowermost convolutions pertaining to the same flues, i. e. those convolutions which contact with the hottest gases, that is to say, on their inner faces.' Now While the gases flow from theinner faces of these convolutions to the outer faces thereof, they must cover practhe inner faces; the sum of the degrees is,

however, in fact, practically the same as at the upper convolutions and so everywhere.

Figure 2 which relates, practically to Fig. 1, shows nevertheless a modification in that this set of convolutions is composed of two I tubes of diiferent diameters, viz a shorter tube of smaller diameter and a longer tube of larger diameter, the first forming the convolutions d and the other the outer convolutions (P. The two tubes are welded together at the portion d There is made up, by this provision, for the increase of volume of the steam by its increase of temperature while flowing through the consecutive columns of coils and the strain to which the tubes are subjected is, in the mean, equal at all portions of all tubes.

I wish it to be understood that I do not limit myself to theconfigurations of the bent tubes shown in the drawing. These configurations or .bends are merely examples' 'Many other shapes of the bent tubes are pos sible without departing from the gist of this invention. That applies also to the flues formed by the-bent tubes, as well as to the flues formed by the surrounding walls.

I claim: a

1. A fluid heating device for furnaces'comprising a plurality of similar superimposed units, eachv unit consisting of a pipe bent to form concentric cylindrical communicating coils,'said units being arranged with said concentric coils in re istering relation, to form heat conducting dues for the furnace and said coils forming a contiguous wall for each flue, and means establishing communication between said flues at one end thereof.

2. A fluid heating device comprising a plumemes rality of similar superim osed units, each unit consisting of a' pipe ent to form concentric cylindrical communicating coils, said units bemg arranged with said concentric coils in reglstering relation to form heat conducting flues and said coils forming a contiguous wall for each flue, means establishing communication between said fines at one end thereof, and a common inlet and outlet header communicating with each of said unitsk In witness whereof I have hereunto set my hand.

' STEPHAN LGFFLER.

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