US1707143A - Superheater - Google Patents

Description

Patented Mar. 26, 1929.

,UMTED [STATES 1mm SCHNEIDER, or KELHEIM-DONAU, GERMANY, nssrenon 'To manna-BAYER- ISCHE CELLULOSEWERKE LAKTIENGESELIISGHAFT, OF KELI-IEIM ON THE DANUBIE,

GERMANY.

SUPERHEA'IER.

Application filed April 22, 1926, Serial .No. 1'03, 9 39, and in Germany August 19, 1925.

This invention relates tomovable superheaters of the type which are heated by radiation, in contradistinction to superheaters in which the super-heater tubes are heated solely by contact with the of combustion.

It has already been proposed to superhea'tsteam by ineans of movable superheaters the latter being movable into or outof the stream of heating gases, to a greater or lesser extent. Superheaters of this type receivetheir heat only fromthe hot gases, and do nottherefore use up the radiant heat of theburning fuel. The heating surfaces must on that account be of unnecessarily large dimensions, which entails the further disadvantage that the uniform heating of the superheater tubes by the hot gases is difiicult to ensure, so that individual tubes may easily be burnt through. Further when the temperature of the hot gases varies the difficulty of regulating the superheater to a constant temperature is greater the greater theheatingsurface of the superheater and the lower the temperature of. the heat transmitting medium.

In order to obviate these disadvantages, movable superheaters have been proposed, which can be moved to a greater or lesser extent behind heating tubes, in order to be able to expose them in this way to the radi ant heat of the furnace to a greater or lesser extent. Superheaters of the above mentioned type possess the disadvantage, that they are too powerfully cooled by the water-conveying heating tubes serving as screens, and that the hot gases cannot flow round the superheater tubes adequately, being prevented from doing so by the heating tubes. The radiant heat of the gas stream itself, as well as the contactheat, can only be imperfectly transmitted when the above mentioned type of superheater tube is employed. In practice, the above mentioned type of superheater has the disadvantage that the position can only be changed by a longitudinal movement a of the super-heater, parallel, for example, to the water tubes so that the distance ofthe superheater from, or its position in, the stream of hot gases, and its position with respect to the fire cannot be altered. This drawback in its turn causes disadvantages from the point of view of both heat and tem perature regulation. Further the movement of the superheater by displacement is also point of ther drawback that the superheater tubes are inthe form of U-shaped 100 as so that thereis consulerable risk of thetu becoming ammed in the packln g means.

The object of the present invention is to obviate all the abovementioned disadvantages, and produce a superheatcr having new advantages. p

The invention is illustrated, by way of example, in the accompanying drawings, in which:

Fig. l is a cross section of a steam boiler" provided with a radiation superheater which is also capable of removing the heat from the hot gases.

Fig. .2 is a side view of a superheater element and Fig. 3 shows several superheater elements to ether with their rotary device.

eferring to the drawings, a is a preheater for air or feed-water, which is heated by the flue-gases from the furnace 7a. of the medium or low pressure boiler b. A Field tube boiler 0 is interposed in front of the boiler Z), and serves as a high pressure boiler, receiving its feed water from the boiler Z) and being heated by the furnace it into which the Field tubes Z depend. At the rear end of the furnace h is a wall on which is capable of obstructing the passage of radiant heat from the burning fuel, which is placed on the grate n, and mounted above the wall on inside the boiler is a superheater cZ comprising a plurality of tubes bent into the form of annular loops. The superheater (Z is pivoted eccentrically with respect to the centres of the loops so as to be capable of being turned from the position shown in full lines in Figure 1 where it rests on the wall at into the position shown in broken lines behind the wall 71 Behind the wall at is a space positions, according to the angle 0:.

o' forming a fiuedust bunker, said space having an opening 70 at the bottom which communicates with the ashpit p. In the position'indicated by broken lines the superheater is Withdrawn from the radiant heat of the fire, as well as from thestream of hot gases. The greatest superheater temperature is attained when the superheater is in the posi tion indicated in fulllines. The temperature can be regulated in between the two It is to be'understood that the invention is not limited to the kinds of; boilers, nor to the particular boiler arrangement hereinbefore described.

The tube coils e, are so arranged in Figs. 2 and-3 that each coil .6 lies in a plane, the superheater tubes being wound in and out sinuously.

The individual elements may however be wound .in any other manner, and if preferred they maybe bent out of; the plane, whereby the'transfer of heat is improved.

' are rotatably mounted in the form of stuffing boxes. 41 is a device for turning the superheater. The two headers f 9' may be united into one single header.

1: What. Iolaim is In Fig. 3 these headers 1. In combination, a steam boiler having a furnace constituting a source of radiant heat within the boiler, said furnace having a wall capable of obstructing the passage of radiant heat, a flue dust bunker within the furnace behind said wall, and a superheater comprising a plurality of tubes bent into the form of annular loops and pivoted in the boiler in proximity to said furnace wall and eccentrically with respect to the centres of the loops so as to be capable of being turned into a position projecting beyond said wall for enabling it to be heated by radiant heat from the furnace and of being turned out of said position behind said wall into the flue dust bunker, as set forth.

2. In combination, a steam boiler having a furnace constituting a source of radiant heat within the boiler, said furnace having a wall capable of obstructing the passage of radiant heat, a flue dust bunker within the furnace behind said wall, and a superheater comprising a plurality of sinuously wound tubes bent into the form of annular loops and pivoted in the boiler in proximity to said furnace wall and eccentrically with respect to the centres of the loops so as to be capable of being turned into a position projecting beyond said wall for enabling it to be heated by radiant heat from the furnace and of being turned out of said position behind said wall into the flue dust bunker, as set .forth.

In testimony whereof I have signed my name to this specification.

ADOLF SCHNEIDER.

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