US2056598A - Steam generating plant - Google Patents

Description

@et 6, 1936a J, V. BLOMQUIST @5659@ STEAM GENERATING PLANT Filed oct. 16, 1954 3 sheets-sheet 1 @cih 6 E93., J. v. BLoMQUlsT STEAM GENERATING PLANT 3 Sheets-Sheet 2 FiledOCt. 16, 1954 @cih 6, E936., J. v. BLOMQUIST STEAM 'GENERATING PLANT Filed Oct. 16, 1934 3 Sheets-Sheet 3 Patented Oct. 6, 1936 Y UNITED STATES PATENT OFFICE STEAM GENERATING PLANT Application October 16, 1934, Serial No. 748,525 In Germany October 17, 1933 12 Claims.

My present invention relates to a steam generating plant comprising a rotatable steam generator assembled by a plurality of substantially straight steam generating tubes arranged around a common axis so as to conne a combustion chamber, and in addition thereto super-heating and pre-#heating surfaces. The main object of my invention is` to construct and assemble the elements included in the plant so as to obtain a simple construction requiring little space and, furthermore, having the advantage of enabling the dimensions of the masonry to be reduced to a minimum.

According to my present invention this is obtained by divi-ding the supply passages for the air of combustion in such a manner that a portion of the air enters through the. circumference of .a part of the rotor formed by the generating-tubes and containing the combustion chamber, and a portion together with the fuel through the end of the rotor, the outlet for `the combustion gases being disposed at the bottom'of the rotor so that the combustion gases escape downwards from the interior ofthe rotor through another portion of the circumference. Thus, the firing takes place within the rotor formed by the steamgenerating tubes, the gases produced at the combuston escaping downwards from the rotor. Rotatable steam generators have been previously proposed in which the firing takes place within the rotor. Such `a steam generator is disclosed by the Swedish patent specification No. l72,605. According to said patent specification, the combuston air flows into the rotor on a portion of the circumference of the combustion chamber through the layer of fuel, and the combustion gases escape through the remaining portion of the circumference. But according to my present invention the combustion gases escape only on a portion of the free circumference and then flow directly downwards passing to and over the heat absorbing surfaces disposed under the rotor to the chimney.

In order that my invention may be clearly understood and readily carried into effect it will be described in the following, reference being had to the accompanying drawings, wherein Figure 1 shows a longitudinal section of a steam generating plant according to the invention,

Figure 2 is a cross section of the same, and

Figure 3 is a cross section of three steam generating tubes together with grate bars and strengthening pieces provided therebetween.

The feed water is pumped through the water heaters I and 2 into the container 3 as indicated by the arrows, and is distributed by the tubes 4, the torus 5 and the tubes 6 to the steam generating tubes 'I. At the other ends the tubes 1 are connected to the container 9. The tubes 8 open approximately at the centre of the tubes 'I in a 5 well-known manner so that the latter are always half filledwith water. The container 9 is also half filled with water, and the water level is a1 ways maintained by an automatic feed water regulator in well known manner. The steam generated in the tubes 'I will thus circulate through the tubes 8 into the container 9 and to the superheater I 0 from which it is led to the place of consumption.

When the fuel consists of coals in the form of pieces, it is supplied by a drum Il and falls through an aperture I2 on a plate I3 by means of which the pieces of coals are deflected and' guided to the space between the tubes 4 and into the combustion chamber I4. The plate i3 is 0 preferably disposed above the axis of the rotor so that the coals are passed eccentrically through the end of the rotor at a point near the top of the combustion chamber. A portion of the combuston air is supplied to the combustion chamber 25 under the plate I3 and laterally thereto, said air carrying away the coals which are stopped by the tubes 4. Due to the movement of the rotor the coals are distributed in a uniform layer I5 along the entire rotor. 30

The air of combustion heated in the twoair preheaters I6 and Il flows substantially through the layer of coals I5 into the combustion charnber I4. The two spaces I8 and I9 above the air preheaters I6 and I'I are connected with each 35 other by a passage 20 from which another passage 2I deflects a portion of the air of combustion to the plate I3 as stated above.

To prevent leakage of air from the space I8 to the chimney ue 22 the air is not blown directly from the air preheater I6 into the space I9 but may previously o-w into the passage 23 which is provided with a restricted aperture 24 through which the air flows into the space I 8 at a high rate. The jet formed by the air and directed obliquely towards the steam generating tubes prevents leakage between the two spaces I8 and 22.

The gases produced in the combustion chamber I4 escape at a portion of the circumference of the rotor through grate bars between the steam generating tubes to the chimney flue 22, flowing therefrom in the direction indicated by the arrows over the superheater I0 and the economizer 2, From this place they are guided to both sides and then flow over the two economizers l through the two air preheaters I6 and I1 to the chimney ues 26 and 2l which are connected tothe suction side of a ventilator supplying the smoke gases to the chimney.

The combustion takes place when the fuel is floating. A rotor designed for a steam generation of for instance 40,000 kg/h at a pressure of 1422 lbs/inch2 has a diameter of 158 and an effective length of 236", and rotates with a speed of 15 revolutions per minute. The coals are therefore moved to the top of the layer of coal in one second. When the layer of coal is very thin, the coals are blown by the air of combustion into the combustion chamber I4 without slipping downwards on the layer of coal but falling directly on the steam generating tubes to be re- A turned upwards successively. At the places where the layer of coal is thick the coals slip rapidly down on the bed of coal, and during this interval no cakes of slag have time to be formed. When the coals have fallen on the tubes, they will be returned-upwards and blown into the combustion chamber. Each particle of coal will thus substantially be burned in a floating state until only ashes and slag remain, which is transferred together with a quantity of unburned coals by the gases of combustion over the superheater l and the economizer 2 to the ash-pit therebelow cleansing continuously the heating surfaces from iiying ashes due to the friction.

The higher the steam pressure and the greater the quantities of generated steam, the greater are the two containers 3 and 9 as well as their wall thickness. The containers adapted for the above-mentioned steam generator designed a steam production of 40,000 kg/h should have a wall thickness of about 3.9" to resist said pressure without exceeding the safe stress. With such wall thickness, however, the additional stresses due to the heating become' too large in case the containers are exposed to the direct heat radiation.

Figure 3 shows a constructional form of the gate bars 2B which are divided radially so that they may be inserted between the steam-generating tubes. Spaced apart are two special strengthening pieces 29 disposed between the grate bars to give the construction suicient strength. The grate bars are cooled sufficiently by the contact with the steam generating tubes the supply of the material being modied corre- 'spondingly What I claim and desire to secure by Letters Patent is:-

l. In a steam generating plant, the combination comprising a rotatable steam generator rotor having a plurality of substantially straight steam generating tubes arranged arounda common axis so as to dene a combustion chamber, means for passing a portion of combustion supporting air to the combustion chamber, through a part of the circumference of the rotor formed by the steam generating tubes, means for supplying another portion of the air together with the fuel through the ends of the rotor, and an outlet for the combustion gases disposed at the bottom of the rotor whereby the combustion gases escape downwards from the interior of the rotor through another part of its circumference.

2. In a steam generating plant, the combination comprising a rotatable steam generator rotor having a plurality of substantially straight steam generating tubes arranged around a common axis so as to denne a combustion chamber, a restricted aperture for passing a portion of the air of combustion tangentially to the steam generating tubes and into the combustion chamber through the circumference of the rotor formed by the steam generating tubes, air supplying means for supplying another portion of the air together with the fuel through the end of the rotor, and an outlet for the combustion gases disposed at the bottom of the rotor, whereby the combustion gases escape downwards from the interior of the rotor through another part of the circumference.

3. In a steam generator of the character described, a squirrel-cage shaped rotatably mounted boiler structure consisting of a plurality of substantially straight steam-generating tubes concentrically grouped around the axis of rotation of said structure, and a series of tubular spokes positioned at each end of the boiler structure supporting the steam-generating tubes and communicating therewith, a hollow hub at one end of the boiler structure, means for feeding water to said hub, said hub being adapted to form a communication` means between said inlet and the tubular spokes at that end of the boiler, a second hollow hub at the opposite end of the boiler structure, steam discharge means connected to said second hub, said last-mentioned hub being adapted to form a communication means between said steam-discharge means and the tubular spokes at the last-mentioned boiler end, pivot and bearing means for supporting the whole boiler structure, and means for introducing fuel between the tubular spokes eccentrically in relation to the axis of rotation of the boiler.

4. In a steam generator of the character described, a squirrel-cage shaped rotatably mounted boiler structure consisting of a plurality of substantially straight steam-generating tubes concentrically grouped around the axis of rotation of said structure, and a series of tubular spokes positioned at each end of the boiler structure supporting the steam-generating tubes and communicating therewith, a hollow hub at one end of the boiler structure, means for feeding water to said hub, said hub being adapted to form a communication means between said inlet and the tubular spokes at that end of the boiler, a second hollow hub at the opposite end of the boiler structure, steam discharge means connected tosaid second hub, said last-menl tioned hub being adapted to form a communication means between said steam-discharge means and the tubular spokes at the last-mentioned boiler end, pivot and bearing means for supporting the whole .boiler structure, and means mounted above the axis of rotation 0f the boiler structure for introducing fuel between the tubular spokes eccentrically relative to and above said axis of rotation.

5. In a steam generator of the character described, a squirrel-cage shaped rotatably mounted boiler structure consisting of a plurality of spaced steam-generating tubes grouped concentrically around the axis of rotation of said structure and connected by tubular spokes with hollow hubs at each end of the boiler structure, feed water inlet means communicating with one of said hubs, steam-discharge means connected with the other hub, pivot and bearing means for supporting the whole boiler structure, means for introducing fuel between the tubular spokes at one end of the boiler eccentrically relative to the axis of rotation of the same, and means for conveying the combustion gases from the squirrel-cage shaped boiler structure through the spaces between the steam-generating tubes thereof.

6. In a steam generator of the character described, a squirrel-cage shaped rotatably mounted boiler structure consisting of a plurality of spaced steam-generating tubes grouped concentrically around the axis of rotation of said structure and connected by tubular spokes with hollow hubs at each end of the boiler structure, feed water inlet means communicating with one of said hubs, steam-discharge means connected with the other hub, pivot and bearing means for supporting the whole boiler structure, means mounted above the axis of rotation of the boiler structure for introducing fuel between the tubular spokes eccentrically relative to and above said axis of rotation, and means for conveying the combustion gases from the squirrel-cage shaped boiler structure through the spaces between the steam-generating tubes thereof.

7. In a steam generator of the` character described, a squirrel-cage shaped rotatably mounted boiler structure consisting of a plurality of spaced steam-generating tubes grouped concentrically around the axis of rotation of said structure and connected by tubular spokes with hollow hubs at each endI of the boiler structure, feed water inlet means communicating with one of said hubs, steam-discharge means c-onnected with the other hub, pivot and bearing means for supporting the whole boiler structure, means for introducing fuel between the tubular spokes at one end of the boiler eccentrically relative to the axis of rotation of the same, means for conveying the combustion gases from the squirrel-cage shaped boiler structure through the spaces between the steam-generating tubes thereof, and a steam superheater mounted in the path of travel of the combustion gases leaving the squirrel-cage shaped boiler structure.

8. In a steam generator of the character described, a squirrel-cage shaped rotatably mounted boiler structure consisting of a plurality of spaced steam-generating tubes grouped concentrcally around the axis of rotation of said structure and connected by tubular spokes with hollow hubs at each end of the boiler structure, feed Water inlet means communicating with one of said hubs, steam-discharge means connected with the other hub, pivot and bearing means for supporting the whole boiler structure, means for lntroducing fuel between the tubular spokes at one end of the boiler eccentrically relative to the axis of rotation of the same, means for conveying the combustion gases from the squirrel-cage shaped boiler structure through the spaces between the steam-generating tubes thereof, and means for introducing a stream of air into the squirrel-cage boiler structure adjacent the fuel feeding means to facilitate the passage of fuel between the tubular spokes.

9. In a steam-generating plant, the combination of a rotatable steam generator rotor oomprising spaced hub-like rotary headers axially aligned, a. plurality of tubes projecting substantially radially from said hubs, and a plurality of steam generating tubes connecting the outer ends of the radial tubes on one hub with those on the other hub, a casing surrounding said generator and defining a combustion chamber within the space surrounded by said tubes, means for passing combustion supporting air through a portion of the circumference of said rotor, means for introducing air and fuel through one end of said rotor, and an outlet duct positioned beneath said rotor to cause combustion gases to pass downwardly from the interior of said rotor through another portion of the circumference thereof.

l0. A rotating steam-generating boiler comprising a pair of axially spaced and aligned hublike headers, means for rotatably mounting said headers, a plurality of tubes connecting said headers and arranged to dene a cylindrical cage-like rotor, and means positioned above one of said hubs for feeding fuel eccentrically between the tubes defining one end Wall of said rotor.

11. A rotating steam-generating boiler, comprising a pair of axially spaced and aligned spider-like headers, means for rotatably mounting said headers, a plurality of spaced tubes connecting said headers and arranged to define a cylindrical cage-like rotor the interior of which is adapted to form a combustion chamber, means for passing a portion of combustion supporting air to said combustion chamber through a part of the circumference of the rotor formed by the inter-space between the tubes, and means provided at one end of the rotor and adapted to introduce another portion of combustion supporting air together with fuel eccentrically relatively to the axis of rotation.

12. A rotating steam-generating boiler, comprising a pair of axially spaced and aligned spider-like headers, means for rotatably mounting said headers, a plurality of spaced tubes connecting said headers and arranged to define a cylindrical cage-like rotor the interior of which is adapted to form a combustion chamber, means for passing a portion of combustion supporting air to said combustion chamber through a part of the circumference of the rotor formed by the inter-space between the tubes, and means provided at one end of the rotor and adapted to introduce another portion of combustion supporting air together with fuel eccentrically relatively to the axis of rotation and at a zone above said axis.

JOHAN VIKTOR BLOMQUIST.

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