US2678535A

US2678535A - Liquid fuel injecting burner

Info

Publication number: US2678535A
Application number: US155525A
Authority: US
Inventors: Jay Kenneth William
Original assignee: AV Roe Canada Ltd
Current assignee: AV Roe Canada Ltd
Priority date: 1950-04-12
Filing date: 1950-04-12
Publication date: 1954-05-18
Anticipated expiration: 1971-05-18

Description

May 18, K; w JAY LIQUID FUEL INJECTING BURNER 2 Sheets-Sheet 1 Filed April 12, 1950 INVENTOR KMJAK HTTORNEX May 18, 1954 w LIQUID FUEL INJECTING BURNER 2 SheetsShee1 2 Filed April 12, 1950 Patented May 18, 1954 LIQUID FUEL INJECTING BURNER Kenneth William Jay, Toronto, Ontario, Canada, assignor to A. V. Roe Canada Limited, Malton, Ontario, Canada, a corporation Application April 12, 1950, Serial No. 155,525

3 Claims.

This invention relates to combustion systems in which a liquid fuel is vapourized before being admitted to the combustion zone and more particularly to burners associated with such systems.

A commonly-used type of vapour combustion system embodies a vapourizer comprising a group of tubes extending into a combustion chamber and through which a liquid fuel or a mixture of liquid fuel and .air is directed into the combustion chamber. The tubes are exposed externally to the burning gases within the chamber,and the liquid fuel flowing through the heated tubes is vapourized before entering the combustion zone; the vapourization of the fuel produces a pronounced cooling effect upon the tubes which protects them against burning.

In order to provide a relatively uniform distribution of the combustible vapour in the combustion zone and at the same time an adequate vapourizing surface, it is customary to employ a number of vapourizer tubes suitably disposed in thecombustion chamber, and it is desirable that the quantity of fuel fed into each tube of the group should be closely controlledso that the distribution of fuel between the tubes may be uniform. To this end fuel is introduced to the group of tubes from a central burner in which is mounted a number of calibrated jets or nozzles, each injecting fuel, at a common supply pressure, into one tube of the group.

The jets or nozzles heretofore employed are unitary members which are difiicult and costly to manufacture because of the accuracy with which the jets must be made in order to ensure uniformity. Furthermore, mounted as they normally are on the outside of the body of the burner, such prior art jets are easily damaged, and their calibration may even be affected by rough handling during assembly.

' The main object of this invention is to provide a burner of such construction that the jets may be readily manufactured in quantity within close tolerances and may be installed in the burner without risk of distortion.

Another object of the invention is to provide adequate protection for the individual jets against accidental damage which may affect their calibration.

Other objects and advantages of the invention will be apparent from the following description of a. typical embodiment thereof.

In the drawings which form a part of this application, and in which like reference characters designate likeparts throughout:

- Fig. 1 isa viewin sideelevation, partlybroken' away, of a vapour system burner constructed in accordance with this invention, shown installed in a typical gas turbine engine, the burner and more relevant portions of the engine being shown in heavy lines; I

Fig. 2 is an enlarged view partly in section, of the vapour system burner and adjacent vapourizer tube assembly;

Fig. 3 is an enlarged sectional view of the vapour system burner and adjacent portions of the vapourizer tubes; and

Fig. 4 is an exploded perspective view of the jet plate and of the jets.

The vapourizer system illustrated comprises a burner constructed in accordance with the invention, and generally indicated by the reference numeral 5, and a group of vapourizer tubes 6, one such vapourizer system being disposed within each of a. number of flame tubes I. According to well known practice, the flame tubes 1, six of which are usually provided, are each enclosed within an outer casing or combustion chamber 8, to which air is supplied by a compressor 9 (shown in phantom lines in Fig. 1).

The vapourizer tubes 6, also in accordance with the usual practice are mounted in groups of six tubes in tube plates I0; such a group of vapourizer tubes mounted in its tube plate I0 is supported in each flame tube 1 by a transverse baflle II. The vapourizer tubes extend downstream of the baffle into the flame zone in which combustion takes place. Upstream of the baffle, the flame tube 1 forms a plenum chamber I2 open at its forward end to the air which enters the combustion system from the compressor 9 in the direction of the arrow A. Air from the chamber I2 enters the upstream ends of the vapourizer tubes 6, which ends protrude forwardly through the tube plate It), and the air passes down the tubes into the flame zone; other air passes down space I3 between the flame tube I and its outer casing, to enter the combustion zone through holes I4.

In accordance with the invention, the burner 5 is preferably centrally mounted on the tube plate I0 adjacent the open upstream ends of the vapourizer tubes 6, and it comprises a body I5, a jet unit in the form of a plate IB having a plurality of jet elements I! equal in number to the number of vapourizer tubes 6, and a .nozzle assembly including a multiple nozzle block I 8. The burner 5 is supplied with fuel from an external source through a pipe I9.

The fuel supply pipe I9 enters the body I5 through a hollow boss 20 which opens into a cylindrical chamber 2|. Leading out of the chamber 2! and symmetrically disposed around the axis of the burner is a number of longitudinal flow passages 22 equal to the number of jets required; the flow passages 22 are preferably of circular cross-section and they extend to the front face of the body.

Each jet element ll consists of a small cylindrical plug having an orifice axially drilled therein and being a light push fit in a housing 15 provided in the jet plate It; the assembly of the jet plate and its associated jets is best seen in Fig. 4. The jet plate it, having a plurality of jet elements il, isclamped between -the body (5 and the multiple =nozzle block [8 by a central bolt 23 which is screwed into the core 35 of the body. Thin compressible sealing washers 24 are provided between the body [5 and the jet plate, and between the jet plate and the multiple nozzle block l8.

The forward portion of the multiple nozzle block {.8 isformed to providea plurality of nozzles 25 extending forwardly and .outwardly'from the .face of the block it and opening out of nozzle responds to one of the jet elements .i'i and is-directed to one of the vapourizer tubes 5.

In assembly, the longitudinal flow passages '22 in the .body .are aligned with the jet elements i and with the nozzle passages 25 to provide metered conduits from the chamber 2! to the open ends of the vapourizertubes t. The thickness of the said jetplate is substantially .thesame as the length of each jet element .so that the faces of the. jet elements, when assembled 'in the'jet plate, are flush with the faces of the said plate. The outside diameter of .eachjet element is little greater than the diameters of the corresponding longitudinal flow passage 22 andof the corresponding nozzle passage 25.; consequently when the jet'assemblyis clamped between the washers 2d, the jet elements are securely held against longitudinal movement or leakage around their peripheries. entry of air into thetubes from .the plenum chamber l2, the burner is set centrally among the tubes and sprays fuel obliquely into their open ends.

In order to provide the required accuracy :of performanc of the jet elements il, itis necessary that their manufacture should be controlled within very fine limits and that the surfaces not only of the bores but also of the inlet :and outlet faces should be highly'finished. It is also important that the jet elements should not be subjected to any distortion during assembly. It will be appreciated that the simple construction according to'this invention enables the inlet and outlet faces to be readily polished. The light push fit assembly in the jet plate it together with the positive longitudinal location achived by the simple clamping action aforementioned, provides a mounting for the jets which is free from the risks of distortion inevitably present in the screwed mounting commonly used. Moreover, the construction of the burner is such that the jet elements are well protected against accidental damage by virtue of their situation inside the burner assembly, although the Whole burner can be readily dismantledfor cleaning or for the replacement of jet elements by removing the single central bolt 23.

Inthe operation of the burner, fuel is introduced to the burner through the pipe. l9. and flows into To minimize the obstruction to the 'bustion zone as 'a combustible gas.

the chamber 2| and the flow passages 22 and through the calibrated jet elements I! to the nozzles 25, whence it is introduced into the vapourizing tubes 6. The air flowing through the tubes carries the fuel with it into the hot region of the tubes, where the liquid fuel is vapourized by theheat of combustion, and the mixture of air and'fuel vapour is discharged into the com- It will be readily understood that to achieve a uniform distribution of the flame in the combustion zone, the discharge of the gases from the individual vapourizer tubes must be uniform. To this end the jet orifices arecarefully calibrated before assembly to allow the passage of a given quantity of fuel within a given time at a given entry pressure and, according to this invention, this calibration may be maintained within very close limits so that, at any given fuel pressure, a substantially equal flow of fuel will be delivered through each jet'to each 'vapourizer tube;

that various changes in the shape,'isize and arrangement of the parts maybe adopted, without departing from the spirit of the invention or the scope of the claims.

What I claim as my invention is:

l. A burner for injecting liquid .fuelinto a vaporizing combustion system comprising. a body having a flat forward face and-a .fiowppassage passing through the body and the said facega nozzle block having a flat rearward face and providing a nozzle, the nozzle block having a nozzle passage extending .from the rearward face through the nozzle, a jet platelocated between the flat races of thebodyand the nozzle block, the plate having flat opposite faces and==a jet orifice extending therethrough anticommunicating with the said passages, the jet-orifice being cross-sectionally smaller than the flow passage and than the nozzle passage to limit the rate of flow throughthe said "passages, andmeans for removably securing the jet plate between-the body and the nozzle block.

2. A burner for injecting liquid fuelinto'a vapour-izing combustion system, comprising "a body' having a flow passage extending through it, a nozzle having a nozzle jpas'sage extending through it, a jet plate having fiat opposite faces disposed between the body and the nozzle and having a housing aperture-extending through it, and a jetelement disposed whollywitliin the housing aperture between the opposite faces "of the jet plate, the jet element also having fiat opposite faces and having an orifice extending between the last-mentioned faces from'th'efiow passage to the nozzle passage to "conduct the fuel between the said "passages, the orifice in the jet element bein smaller than'the flow passage and smaller than the nozzle passage and thus providing a flow-limiting constriction determining the rate of flow through'the "said passages.

3. -'A burner for-injecting liquid fuel into a vapourizing-combustion'system comprising a body having a cylindrical flow passage through "it, a nozzle spaced from the body and defining a cylindrical nozzle passage, "a jet plate disposed in'the space between the body and the nozzle and having a housing aperture extending through it, and a cylindrical jet element in the housing, the "jet element havin an axial orifice registering with the said passage,".the' diameter of the jet element being greater than the' diameter of the 'flow passage and than the nozzle passag and the orifice in the jet element being cross-sectionally smaller than the flow passage and than the nozzle passage and thus providing a flow-limiting constriction determining the rate of flow through the said passages.

References Cited in the file of this patent UNITED STATES PATENTS Number Number Number Name Date Kummerer July 5, 1932 Meyer et a1. June 17, 1947 Williams Feb. 13, 1951 Buckland et a1. May 6, 1952 FOREIGN PATENTS Country Date France Oct. 21, 1929