US1965427A

US1965427A - Elastic fluid generator and the like

Info

Publication number: US1965427A
Application number: US628519A
Authority: US
Inventors: Anthony J Nerad
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1932-08-12
Filing date: 1932-08-12
Publication date: 1934-07-03
Anticipated expiration: 1951-07-03

Description

Jlxlvy Y1934- A. J. NERAD 1,965,427

ELASTIC FLUID GENERATOR AND THE LIKE Filed Aug. l2, 1932 2 Sheets-Sheet l His Atto-Wheg` July 3, 1934.4 A. J. NERAD g 1,955,427

ELASTIC FLUID GENERATOR AND THE LIKEA Filed Aug. l2, 1952 2 Sheets-Sheet 2 Inventor: /Ambho'ng J. Nercld,

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Patented july 3, i934 ENT Friesl I Anthony J. Nerad, Schenectady, N. Y., assigner to General Electric Company, a corporation of New York Application Aiigust 12, 4193e, serial No. 628,519

l. Claim.

The present invention relates to elastic uid generators and like apparatus in which a fluid is heated, vaporized and superheated.

In apparatus of this kind the fluid to be heated is contained in containers such as drums and heating pipes or conduits. The heat is transmitted to the fluid containers mainly by radiation and conduction and the amount of heat thus transmitted depends upon the area of the surfaces of the containers which are in contact with the heat carrying flames or gases.

It is known that in a small steam generating apparatus the heat release per cubic foot of furnace volume can be much greater than lin a large one, owing to the greater cooling effect of a small steam generating apparatus. A geometrical consideration shows that a small furnace has a. greater ratio of wall surface to volume than a large furnace of similar shape.

Since the heat absorption per unit area of the boiler tubes is the same regardless of the size of the furnace, it is evident that combustion can take place at a higher rate per unit volume in a small furnace owing to the fact that a small furnace Oilers relatively more space for heat absorbing Wall's and tubes at a high velocity of the fire gases than a large size furnace.

The object of my invention is to provide an improved fluid-heating apparatus such as an elastic fluid generating arrangement wherein the heat-absorbing surfaces are large in comparison with the dimensions of the entire apparatus. Such an apparatus is particularly advantageous where little space is available as in ships and airplanes.

For a consideration of what I consider to be novel and my invention, attention is directed to the following description and the claim appended thereto in connection with the drawings which form a part of my specification.

In the drawings, Fig. 1 is a view, partly in cross section and partly diagrammatic, of an elastic fluid generating arrangement embodying my invention, the arrangement shown being one well adapted for use in a mercury steam power plant; Fig. 2 is a cross section alorg`line 2--2,

Fig. 1, whereas Fig. 1 represents a section along line 1-1, Fig. 2; Fig. 3 is a cross section of a part shown in Figs. 1 and 2 to an enlarged scale; and Figs. 4 and 5 illustrate a modification embodying my invention, Fig. 4 being a section along line 4 4, Fig. 5 and Fig. 5 a section along line 5 5, Fig. 4.

Referring to Figs. 1 to 3, 6 designates the outer wall of a furnace or boiler. '7 is a conduit through which combustible material, for example, pulverized coal together with primary air, is fed to a plurality of burners 8. Provided in the interior of the furnace are containers, including drums 9 and heating elements 10 containing a fluid such as mercury. The mercury is vaporized in these elements and drums, which latter are connected through conduits 11 to a header 12 supplying the vapor thus generated to a mercury turbine 13 having a valve 14 for regulating the admission of fluid in the usual manner. The heat contained in the exhaust of the turbine is transmitted to another fluid, such as water, by the provision of a condenser boiler 15 connected to the exhaust of the turbine. The mercury condensed in the condenser boiler is then fed by gravity or by means of a pump 16 through a conduit 17 including a check valve 18 for preventing back flow of fluid, to a lower header or headers 19 connected in series with elements 10 and drums 9. The transmission 0f heat from the mercury to the water supplied to the condenser boiler through a conduit 20 causes vaporization of the water. The steam thus generated is conveyed from the condenser boiler through a conduit 21 to a superheater 22 subject to the heat of the flue gases,

-whence the superheated steam is conveyed through a conduit 23 to any kind of apparatus in which it is utilized. The flue gases after passingsuperheater 22 pass through a preheater 24 through which air is forced in a double pass by means of a blower or fan 25. The air leaving chamber 24 is conveyed to channels 26 having their lower parts surrounding the burners whereby this air assists the combustion of the fuel, acting as secondary air in the well known manner.

The apparatus so far described may be considered typical of any kind of fluid heating or elastic fluid generating arrangements, particularly of those used in mercury steam plants where the heat contained in the mercury vapor after leaving the turbine is submitted to a second medium, preferably water, for generating steam to be utilized in other turbines or like consumers.

According to my invention, I provide an arrangement in which a plurality of small combustion chambers are provided in order to obtain the advantages of small fluid-heating apparatus as regards the ratio between the area of the heatcontacting surfaces and the volume of the combustion chambers.

In the embodiment of Figs. 1 and 2, I have shown a plurality of chambers which are defined by the heating elements themselves. Figs. 1 and 2 show three

combustion chambers

27, 28 and 29 respectively. Each of these chambers is deiined by heating elements 10. One of these elements is shown in Fig. 3 in cross section to an enlarged scale as comprising an outer corrugated casing wall 31 and a plurality of tubes 32 within the casing embedded in a copper casting 33 filling the space defined between the heating tubes and the outer 'I'his is a known construction for heating elements which has been used in mercury vapor generators. 'Ihese heating elements have the advantage that they provide for good heat conduction to the heating tubes and in the present instance they also have the advantage that they permit the omission of special walls for deiining the diierent chambers. From Fig. 2 it will be readily seen that the walls between

chambers

27, 28 and 29 respectively are defined by the heating elements themselves. Adjacent heating elements define clearances 34 to permit expansion of the elements and at the same time an equalization of combustion in the different chambers. The heating tubes of the heating elements provided at the side Walls of each heating chamber are directly connected into drums 9. The tubes of the heating elements deflning the rear and front wall of each combustion chamber have extensions 35 (Fig. 1) connected into equalizing conduits 36 which latter connect the different drums with each other. The lower portions of the tubes of the heating elements have extensions connected to a lower header or headers 19 by means of conduits 37 extending across the side walls of the heating chambers. To provide for good circulation of the iiuid to be heated in the elements and the drums, I connect the drums by means of

conduits

39 and 39a extending along the outside of the furnace wall, with the lower header or headers 19. The combustion chambers are long and of comparatively small cross section. This causes a high velocity of the fuel particles burned therein. The vertical arrangement of the heating tubes results in a good heat distribution.

The heat contained in the gases escaping from the combustion chambers is utilized in a gas chamber, this term being used as a heat in this chamber is carried primarily by gases. Said chamber may also be termed a conduction chamber as the heating therein takes place primarily through conduction between the gases and the elements to be heated in contrast to the combustion chamber where heating takes place primarily by radiation. As the temperature of the gases in the gas or conduction chamber is considerably lower than in the combustion chamber, I increase the heating surface by increasing the number of heating tubes in this chamber. In the present example, I have shown a plurality of tube groups 40, each comprising four 'tubes connected by separate upper headers 41. Four such tube groups form a row of tubes with the tubes of each row connected at their lower ends to a common lower header 42. In the present instance, I have shown nine rows of tubes. The upper headers of the groups are connected to drums 9`and the lower headers of the rows of tubes are connected to conduit 39a by means of conduits 44. The tube 39a which in substance is a circulation tube, extending along the outside of the gas chamber, is connected to the drums 9 of the gas chamber. The circulating arrangement for the uid is not further described as any known arrangement may be provided for causing' the transmission of heat to the iiuid by convection.

The lower parts of the combustion and the gas chamber dene a space or intermediate chamber 46 having an opening 47 closed by a cover 48 for removing slag and ashes. The gases during their passage from the combustion to the gas chamber change their direction of flow, to the elect that great turbulence takes place within intermediate chamber 46, causing a complete combustion oi' the fuel. The heat contained in the gases leaving the gas or conduction chamber is absorbed in the super-heating chamber 22 and the secondary air-preheating chamber 24 which are connected in series with the combustion and the conduction chamber as regards the flow of gases.

Whereas I have shown in Figs. 1 and 2 an arrangement in which the combustion chamber and the gas chamber are provided adjacent each other with an intermediate chamber for connecting them to each other, I have shown in Figs. 4 and 5 an arrangement in which the gases leaving the combustion chamber 'low directly into the conduction or gas chamber.

Referring more speciically to the arrangements illustrated in Figs. 4 and 5, 50 designates a furnace or boiler wall having a lower space in which a plurality of heating elements 51 are provided in a manner to define a plurality of

combustion chambers

52, 53, 54 and 55. 'I'he arrangement of the heating elements dei-ined in these chambers is substantially the same as that shown in the left hand part of Figs. 1 and 2. The tubes of each element are connected together at their upper ends as indicated at 56 of Fig. 4 to one end of conduits 57 having their other ends connected to drums 58. The lower ends of the heating tubes are connected through conduits 59 to a header 60 which in turn, through tubes 61 extending along the outside of. the furnace, is connected to the drums 58. The upper space of the boiler defining a conduction or gas chamber into which the gases escaping from the combustion chamber pass is provided similarly to the arrangement shownfin Fig. 1 with a greater number of tubes. A plurality of tubes with their upper ends connected together by headers 62 deiine groups 63. A plurality of groups, in the present instance four, dene rows of groups with the tubes defining the groups connected together at their lower ends to a common header 64. The lower headers 64 are connected to the circulating pipes 61 whereas the upper headers 62 of each group are connected through conduits 65 to the drums 58. The latter are connected together by means of conduits 66 to a main header 67 from which elastic fluid may be supplied to a turbine or like apparatus as described in connection with Fig. 1. Make-up or condensed fluid is supplied to the lower headers in the combustion and the conduction chamber through a conduit 68. The arrangement shown in Figs. 4 and 5, due to its compactness, is particularly adapted to airplane and like installations where little space is available.

Having described the method of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is,--

In an elastic iiuid generating arrangement, a plurality of vertical walls defining a combustion and a gas space, heating elements in the combustion space arranged to dene a plurality of including upper headers connected to. the drums, lower headers for the groups connecting the lower ends of the tubes of a plurality of groups tcgether to deiine rows of groups, means for permitting circulation of fluid between the drums and the lower headers of the rows oftubes and the elements respectively.

' ANTHONY. J. NERAD.