Patent Publication Number: US-11022312-B2

Title: Connection device comprising several curved concentric tubes

Description:
TECHNICAL FIELD 
     The invention relates to a device making the connection of a turbomachine member, such as an injector of an aircraft turbomachine, with a fuel supply system. 
     The invention more particularly relates to a connection device including several identically curved concentric tubes. 
     STATE OF PRIOR ART 
     An aircraft turbomachine includes in particular a fuel supply system comprising an injector the purpose of which is to inject a certain amount of fuel in the combustion chamber of the turbomachine. The amount of fuel injected depends on the operating conditions of the turbomachine. 
     An injector, in particular of the aeromechanical type, comprises a first so-called primary exhaust flow, which is used during a starting phase of the turbomachine and a second so-called secondary exhaust flow, which is used after starting the turbomachine, and through which a significant fuel flow rate is provided. 
     The supply system provides several different fuel flows to the injector. Each of these different flows is associated with and supplies an exhaust flow of the injector, that is a primary flow supplying the primary exhaust flow, and a secondary flow supplying the secondary exhaust flow. 
     A connection device is arranged between the injector and the supply system, to lead the different fuel flows through restricted spaces. 
     Because of the small space available for conveying fuel flows, the connection device comprises several concentric tubes which delimit several conduits through which the fuel flows circulate. 
     Generally, a connection device comprises three tubes which delimit three concentric conduits. A first central conduit is associated with the primary flow, a second radially intermediate conduit is associated with the secondary flow and a third radially outer conduit is associated with a fuel flow making a thermal protection of the primary and secondary fuel flows. 
     The tubes of the connection device are bent, or curved, to gain access to the location of the injector associated, by taking the integration requirements on the turbomachine into account. 
     According to a conventional manufacturing mode, the tubes are simultaneously curved. 
     To that end, helical springs are installed between the tubes, to keep the tubes remote from each other during curving operations. 
     However, as a result of these curving operations, the thickness of the tubes is not constant over the entire length thereof, there are manufacturing dispersions or even proofness issues. 
     The purpose of the invention is to provide a connection device enabling these issues to be solved. 
     DISCLOSURE OF THE INVENTION 
     The invention provides a device for connecting a member to a system for supplying the member with fluid, the connection device including several concentric tubes delimiting conduits for supplying the member, which are curved along at least one direction, characterised in that it is made as a single piece including at least the tubes. 
     Preferably, the connection device includes at least one radial rib extending between two adjacent tubes, which extends along the central curve of the tubes over the entire length of said adjacent tubes. 
     Preferably, each rib is made as a single piece with said adjacent tubes. 
     Preferably, the connection device includes three concentric tubes and two sets of ribs, the ribs of a first set of ribs connecting the outer surface of the radially inner tube to the inner surface of the radially intermediate tube and the ribs of the second set of ribs connecting the outer surface of the radially intermediate tube to the inner surface of the radially outer tube. 
     Preferably, fillets are formed at each radial end of each rib, at the connection of said radial end of the rib with the wall facing an associated tube. 
     Preferably, the connection device includes a body for connecting the tubes with a fluid injecting system, and said body is made as a single piece with the tubes and the ribs. 
     Preferably, the body includes a securing plate and fillets are formed at the connection between the outer surface of the radially outer tube and each surface of the plate. 
     Preferably, the connection device is made by implementing a direct metal laser fusion method. 
     The invention also relates to a circuit for supplying with fluid a turbomachine member such as a fuel injector for a combustion chamber of an aircraft turbomachine characterised in that it includes a connection device according to the invention. 
     The invention also relates to an aircraft turbomachine including at least one member connected to a system for supplying the member with fluid by a connection device according to the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further characteristics and advantages of the invention will appear upon reading the detailed description that follows for the understanding of which the appended figures will be referred to in which: 
         FIG. 1  is a perspective schematic representation of a fuel supply circuit of an injector including a connection device according to the invention; 
         FIG. 2  is a radial cross-section view of the connection device showing the different tubes and radial ribs; and 
         FIG. 3  is an axial cross-section view of the connection device showing the body of the connection device with the tubes. 
     
    
    
     DETAILED DISCLOSURE OF PARTICULAR EMBODIMENTS 
     In  FIG. 1 , a circuit  10  is represented for supplying with fuel a fuel injector (not represented) for a combustion chamber of an aircraft turbomachine. 
     This injector is designed to be able to selectively inject two distinct fuel flows. These fuel flows are a primary flow, which is injected during a starting phase of the turbomachine and which is not much significant, and a more significant secondary flow, which is injected when the turbomachine is in use. 
     Since the specificities of each of both fuel flows are different, both these flows are consequently separated at the injector exhaust as well as in the entire supply circuit  10 . 
     The supply circuit  10  also includes a supply system  12  which distributes a single fuel flow from a high pressure pump, into several different flows supplying the injector, and controls the pressure and the flow rate of each of these fuel flows. 
     The supply system  12  is connected to the injector through a connection device  14 . 
     This connection device  14  includes a body  16  which is connected to the supply system  12  and a piping  18  extending from the body  16  to the injector. 
     The piping  18  is shaped to circulate the different fuel flows towards the injector. For that purpose, the piping  18  is divided into several concentric supply conduits  20 ,  22 ,  24 , herein three in number as can be seen more in detail in  FIG. 2 . 
     The piping  18  includes a first radially inner conduit  20  which is associated with the first fuel flow, a second radially intermediate conduit  22  which is associated with the second fuel flow and a third radially outer conduit  24  which is associated with a stagnant fuel flow acting as a heat screen. This stagnant fuel in the third conduit  24  aims at protecting the other two fuel flows from heat, and thus at avoiding in particular fuel cocking phenomena inside the fuel injector. 
     The piping  18  consists of several concentric tubes  26 ,  28 ,  30 , three in number, which delimit the conduits  20 ,  22 ,  24 . The first conduit  20  is thus delimited by the radially inner tube  26 , the second conduit  22  is delimited by the radially inner tube  26  and the intermediate tube  28  and the third conduit  24  is delimited by the intermediate tube  28  and the radially outer tube  30 . 
     The tubes  26 ,  28 ,  30  are connected to the body  16  of the connection device  14 . 
     The piping  18  is curved, to enable the connection device to be integrated to the turbomachine by taking the other components of the turbomachine located in the proximity thereof into account. Consequently, the concentric tubes  26 ,  28 ,  30  are also curved along at least one direction. 
     The piping  18  also includes means for keeping the tubes  26 ,  28 ,  30  remote from each other, which consist of a plurality of radial ribs  32 . 
     Each rib  32  is curved in the same way as the piping  18 , that is it radially extends along the central curve of the piping  18  and the tubes  26 ,  28 ,  30 , over the entire length of the tubes  26 ,  28 ,  30 . 
     The ribs  32  are located in the second conduit  22  and in the third conduit  24 , thus forming two sets of ribs, the ribs  32  of the first set of ribs extending in the second conduit  22 , the ribs  32  of the second set of ribs  32  extending in the third conduit  24 . 
     Here, each set of ribs includes four ribs  32  distributed at 90 degrees. It will be understood that a set of ribs can include a different member of ribs  32  without departing from the invention. 
     Likewise, the ribs  32  of both sets of ribs are disposed about the central curve of the piping  18  with two adjacent ribs  32  being aligned. 
     According to the embodiment represented in the figures, the ribs  32  are all of the same thickness. According to an alternative embodiment, some ribs  32  have a different thickness from the thickness of the other ribs  32 , to locally modify the mechanical strength to the piping  18 . Consequently, the thickness of a rib can vary along the central curve of the piping  18 . 
     Each radial end of each rib  32  comprises an extra material forming a fillet  34  at its connection with the associated face of a tube  26 ,  28 ,  30 . These fillets  34  are intended to remove the sharp edges that can locally embrittle the connection between a rib and the wall facing a tube  26 ,  28 ,  30 . 
     The body  16  of the connection device  14  comprises a cylindrical part  36  which is for receiving a complementary part of the supply system  12  and which separately communicates with each of the conduits  20 ,  22 ,  24 . 
     The body  16  includes a plate  38  for securing the connection device  14  to the turbomachine. This securing plate  38  extends about the radially outer tube  30  and fillets  40  are formed at the connection between the securing plate  38  and the outer tube  30 . 
     Preferably, all the tubes  26 ,  28 ,  30  are made as a single piece from a same material. 
     According to another aspect of the connection device  14 , the ribs  32  are made as a single piece with the tubes  26 ,  28 ,  30 . 
     According to yet another aspect of the connection device  14 , the body  16  of the connection device is made as a single piece with the tubes  26 ,  28 ,  30  and the ribs  32 . 
     Thus, according to a preferred embodiment of the invention, the entire connection device  14  is made as a single piece. 
     According to a preferred embodiment, the connection device  14  is made by implementing a so-called direct metal laser fusion method. Such a method consists in distributing an even layer of metal powder by means of a recoating device, and then melting this layer at given locations corresponding to a section of the connection device in a highly controlled inert atmosphere. These operations are repeated several times until the connection device  14  is obtained. Once ended, the connection device  14  is removed from the powder bed and subjected to a heat treatment and a finish. 
     Thus, the connection device  14  does not undergo any shaping step which would be complex to implement and would be at risk of locally embrittling it. 
     All the parts of the connection device  14  are made in a single material which is for example a Cobalt Chromium Molybdenum alloy or an alloy known as Inconel  718 . 
     Such an embodiment of the connection device  14  has the further advantage that no proofness means is necessary between the different tubes  26 ,  28 ,  30  and the body  16  of the connection device, thus reducing the risks of fuel leaks or incidental communication of two conduits  20 ,  22 ,  24 . 
     Thereby, the strength of the connection device  14  is improved since it is possible to adapt the thickness of a tube  26 ,  28 ,  30  or a rib  32  as a function of the stresses it undergoes.