US1900558A - Nozzle channel construction for explosion turbines - Google Patents

Description

Y March 7, 1933.

H. HOLZWARTH 1,900,558

NOZZLE CHANNEL CONSTRUCTION FOR EXPLOSION TURBINES Original Filed Feb. 25. 1929 3 Sheets-Sheet l uni - March 7, 1933. 4 v HQLZWARTH 1,900,558v

NOZZLE CHANNEL CONSTRUCTION FOR EXPLOSION TUR BINES Original Filed Feb. 25, 1929 SSheets-Sheet 2 W N S [N VENTOR o A TTORNE s March 1,1933. H. HOLZWANRTH 1,900,558

NOZZLE CHANNEL CONSTRUCTION FOR EXPLOSION TURBINES A ZTORNE n5" Original Filed Feb. 25, 1929 3 Sheets-Sheet 3 I and more particularly Patented Mar. 7, 1933 UNITED STATES PATENT OFFICE m 00., OF SAN FRANCISCO TUB- CALIFOBNIA, A CORPORATION OF NOZZLE CHANNEL CONSTRUCTION FOB EXPLOSION TUBIBINES Application fled rem as,

1929, Serial no. mess, and in Germany larch 1a, 1928. Renewed October 1, .1882. r

to explosion turbines to the construction of the nozzle channel located between the outlet end of a combustion chamber of such tur- My invention relates 5 bineand its associated nozzle.

In the operation of explosion turbines, sue

cessive charges of air and fuel are exploded in the combustion chamber or chambers associated with the rotor of such turbine, and upon opening of the discharge or nozzle valve at predetermined instants the. combustion ases are permitted to escape from the comustion chamber into a nozzle channel which directs them to a nozzle located adjacent to the blades of the rotor. The combustion gases are at a very high temperature andspressure as they enter the nozzle channel so that this element is constantly exposed to severe heat and pressure stresses.

It has hitherto been the practice to cast all of the nozzle channels for all of the combustion chambers integral with each other and with the machine frame. Such procedure had the disadvantage that if one of the nozzle channels was imperfectly cast the whole casting had to be discarded; also if one of the cast ings had some latent defect therein which was not obvious upon inspection, the same was very liable to crack under the severe stresses to which it was exposed during the operation of the turbine, in which event thewhole machine had to be dismantled and the whole casting, which may have as many as ten nozzle channels formed therein, removed. Furthermore, hen it has been the endeavor to make these nozzle channels as small as possible to avoid too large a loss of heat therein, the difiiculty in casting was increased because the cores necessarily had to be small and as a result were easil displaced from theirproper ositions by t e stream of molten metal during the casting operation. This was a serious disadvantage as each nozzle had to be correctly dimensioned both as tovolume and surface area and in its position relative to the other channels.

It is an object of the present invention to overcome the above-mentioned disadvantages and I accomplish the same by so constructing the nozzle channels or individual channel 4 inserts that the rigidity of the former con.-

structions is not sacrificed, but the necessity of accurate casting of the portion remaining integral with the frame is avoided. To this 7 end I cast the machine frame in the known manner but provide enlarged openings or bores therein adapted to receive individual channel inserts whlch are fixed to the machine frame in the manner described hereinbelow. As a result, an apparent or latent defect in one of such channel inserts has no eflect'upon the remainin inserts and the same can bemore easily an insertsare provided with cooling jackets to which a cooling medium may be charged to prevent overheating of the face of such channel inserts which is in direct contact with the hot combustion ases. I also so position these inserts within t eir respective bores that air 'ackets or pockets are formed between the inserts and the opposing walls of the machine frame and in this manner protect the'main frame casting from the heat and pressure of the combustion gases. c

The nozzle inserts are so constructed as to provide seats at their upper ends for the discharge or nozzle valve for the associated combustion chamber and are fixed at such end to the machine frame. The jacketed walls of the inserts may be made either rigid or flexible. In the first case the other ends of the channels are cast to project into-annular grooves in the nozzle ring which are provided with yielding gaskets in such manner as to permit expansion of the nozzle channels at the high temperatures prevailing therein. 'Wherc, however,-such inserts are provided with flexible walls they may be rigidly connected to the nozzle'ring, the flexible walls taking up the expansion resulting from the heating thereof. I preferably provide also means in the form of flanged rings which are fixed upon the outlet ends of the channel inserts and serve to close theair jackets or pockets to insure against the flow of gas currents therein.

Inthe accompanying drawings are shown two embodiments of the inventive idea, but the same are to be understood as being shown by way of example only and not by way of limitation. In said' drawings Fig. 1 is a more economically replaced. The

radial sectiontaken through a nozzle channel and showing theoutlet end of a combustion chamber and a nozzle channel insert associated with such chamber, the insert being formed of ri id walls; Fig. 2 is a' similar view of anot er form of m invention in which the channel insert is ormed of thin flexible walls; Fig. 3 is a partial section through a turbine plant embodying my invention; Fig. 4 is a section along the line 4--4 of Fig. 2; and Fig. 5 is a section along the line 5-5 of Fig. 3.

Fig. 1 shows the outlet end of a combustion chamber a from which the combustion gases are discharged upon opening of a nozzle valve 6 movable in a housing 0 located in the water or oil cooled machine frame or housing (1, the gases escaping into a nozzle channel in nozzle insert e by which they are directed into a nozzle 7 arranged adjacent to bla des g of the rotor 12.. The nozzle valve 6, as well as the inlet valves of the explosion chamber a,-is operated at the proper instants by any known mechanism, as by a hydraulic distributor of the type shown in the patent to Holzwarth No. 877,194.

In accordance with the present invention the nozzle channel e is not cast inte ral with the machine frame or housing at but is formed of a separate element or insert which is positioned' within an enlarged bore within such frame. The inserts are provided at theirupper'ends with an annular flange which serves as a seat for the nozzle valve band is fixedby means of screws 13 passing through such flange to the machine frame, suitable packing being preferably also provided to insure a gas-tight connection therebetween. The other or outlet ends of the inserts are provided with annular ribs or rejections e which are adapted to fit slida 1y into annular ooves f in the nozzle ring f", yielding gas ets or packings k being positioned between the opposing faces of the groove f and the rib e. The

nozzle ring is fixed to the machine frame by means of screws Z. The nozzle insert e is double walled to provide acooling jacket or chamber adapted to receive a cooling medium such as steam, oil or water, which is charged thereinto by means of a conduit m and withdrawn therefrom through a conduit n. The channel insert is preferably provided with a rib e" which is so positioned with respect to the conduits m and n as to force the cooling medium to traverse the whole surface of the inner wall thereof and thereby pre-' vent the formation of stagnant pools or pockets in the cooling chamber. The bore d" in the machine frame, designed to receive the channel insert, is made of larger internal diameter thanthe external diameter of the insert both to facilitate insertion of the latter into such bore and also to provide an insulating air jacket (1 between suchchannel insert andthe adjacent walls of the machine frame.

During the operation of the turbine the hot gases travelling through the channel e heat the latter and cause expansion thereof. This expansion is taken up y the sliding connection between the outlet end of the channel insert and the nozzle ring so that no undue stresses are set up m the several elements as a result thereof.

In the embodiment illustrated in Fig. 2 the upper or nozzle valve end of the insert 6 is shown attached to the machine frame in a manner similar to that shown'in Fig. 1, a I

threaded flanged ring p which is rigidly connected to the nozzle ring f" and to the machine frame d by means of the screws 1. The end face of the channel and the ring p and the opposing face of the nozzle ring f are provided with grooves for receiving a gasket or packing g. The advantage of emplo ing a separate r1ng such as p is that the assem led ring and insert are more easily 'nachined, so as to make a close fit with the machined rear face of the nozzle ri f", than is the face of the machine frame contacting the nozzle ring in Fig. 1. During the operation of the machine the expansion of the nozzle channel insert, whose ends are rigidly connected to the machine frame, is taken up by the flexible walls thereof and dangerous stresses therein thereby avoided.

It will be noted that in both Figs. 1 and 2 the walls, and particularly the gas-swept walls, of the insert 6 are considerably thinner than the walls of the machine frame, the walls of the insert in Fig.2 being even thinner than those of the insert in Fig. 1 for the reasons given above. This construction reduces very greatly the stresses arising in the body of the insert due to the difi'erence in temperature between the inner and outer faces of the gas-swept walls thereof, so that such insert is not subjected to excessive thermal stresses. The channel-insert walls can safely be made quite thin compared with the walls of the frame, as such insert walls are not subjected to the weight, shock, vibration, and other stresses WhlCll the frame must withstand. The insert thus eifectively protects the necessarily thick walls of the turbine frame against the hot combustion gases, which walls, in the absence of the insert, would suffer so large a temperature differential between the gas-swept and water-cooled faces thereof as to be in constant danger of rupture.

The mechanism shown in Figs. 2 and 4 may be assembled as follows: The member 0 is first inserted into the machine frame d and made to rest with its flange upon the support provided therefor, as shown at 0, and is then fixed to such support by screws The ring 1) is then screwed into the threaded outlet end of the insert 6. The surface 9', which comprises the outer surfaces of the ring 77 and the end of the insert 0, is then planed until it is parallel with the surface of the housing at against which the ring 1) engages. Holes for the screws Z are then drilled and tapped, and the nozzle put into place and clamped by means of the screws Z.

Fig. 3 shows a general view of the turbine plant, the combustion chambers a being shown supported at their ends by the annular frame castings d andr. Fig. 5 is a View of the casting d and illustrates the size and complexity of the same. \Vith very large turbines it is generally desirable to make this casting of two semi-annular sections which are bolted or otherwise connected to each other. Fig. 4 shows more clearly the construction of the expansion nozzle 7 which directs the explosion gases against the rotor blades.

Variations may be resorted to within the scope of the appended claims without depart ing from the spirit of the invention.

I claim:

1. In an explosion turbine, in combination. a frame, a combustion chamber supported by said frame and mechanism for periodically charging said combustion chamber with an explosive mixture to be exploded therein, a nozzle valve adapted to be opened at predetermined instants to'permit discharge of the-combustion gases from the combustion chamber, a rotor, a nozzle supported by and within said frame and arranged to discharge the combustion gases against said rotor, a connecting channel member insert disposed between the outlet end of said combustion chamber and said nozzle to conduct the hot, rapidly flowing gases to the latter, and positioned within said frame and separate therefrom so as to protect the same against 2. The combination as set forth in claim 1, wherein the channel member insert is constructed at its inner end to provide a seat for the nozzle valve of the combustion chamber.

3. The combination as set forth in claim 1, wherein the outer end of the channel member insert is attached to the frame of the turbine, the walls of the insert being sufficiently thin to be capable of flexing to take up thermal expansion.

4. The combination as set forth in claim 1, wherein the channel member insert is spaced from the adjacent walls of the machine frame, whereby an insulating air jacket is formed therebetween.

HANS HOLZWARTH.

the direct heat of the gases, said channel member insert consisting of two walls enclosing a cooling chamber and being fixed at its inlet end to said frame, a conduit for conducting a cooling medium to, and a conduit for withdrawing the same from said cooling chamber, whereby the inner gasswept wall of said channel member insert may be made relatively thin so that during the operation of the turbine such a small temperature differential exists between the inner and outer surfaces of such wall that no excessive stresses arise therein.

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