FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
& The Patent Rules, 2003
COMPLETE SPECIFICATION
1.TITLE OF THE INVENTION:
HOUSING OF A GASKET FOR A TURBOMACHINE INJECTOR
2. APPLICANT:
Name: SAFRAN AIRCRAFT ENGINES
Nationality: France
Address: 2 boulevard du Général Martial Valin, 75015 PARIS, France.
3. PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the invention and the manner in which it
is to be performed:

DESCRIPTION
TECHNICAL FIELD
The invention relates to fluid injectors for a turbomachine 5 of an aircraft,
such as turbojet engines and turboprops. It relates in particular to injectors of the
aeromechanical type.
PRIOR ART
The intake bodies of a fuel injector for a turbomachine with a known
10 structure comprise a casing, an inlet nozzle which is accommodated inside the casing and
configured to be used as a seat for a mobile stopper.
The inlet nozzle comprises a central pipe for the passage of fluid and an
annular rimsurrounding the central pipe. The annular rimcomprises a housing for a gasket.
Said gasket has a tendency to come out of its housing at least partially,
15 which can cause the blockage of the stopper in a closed position and stop the supply of fuel
to the combustion chamber by the injector.
DESCRIPTION OF THE INVENTION
The invention aims to at least partially solve the problems encountered
in the solutions of the prior art.
20 With regard to the latter the subject matter of the invention is an inlet
body for injecting fluid for a turbomachine. The inlet body comprises a casing and an inlet
nozzle accommodated inside the casing, the inlet nozzle being configured to be used as a
seat for a mobile stopper.
The inlet nozzle comprises a central pipe for the fluid, and an annular rim
25 surrounding the central pipe. The annular rim comprises a housing for a gasket.
The housing is delimited by a base wall, an opening opposite the base wall
and two opposite walls, which each extend between the base wall and the opening.
According to the invention, the walls are inclined towards one
another in the direction of the opening. The gasket is crimped into the housing by the walls
which are inclined towards one another in the direction of the opening. The annular rim
comprises an evacuation pipe leading into the housing and to the exterior of the inlet
nozzle, the evacuation pipe being configured to evacuate 5 fluid out of the housing.
The form of the housing according to the invention makes it possible to
limit the chances of the gasket escaping from its housing. The risks of the stopper getting
blocked in the closed position due to a displacement of the gasket are then reduced. The
frequency of maintenance operations or having to replace the body of the injector can be
10 reduced. The evacuation pipemakes it possible to evacuate fuelwhichwould be introduced
into the housing and which would tend to make the gasket come out.
The invention can comprise optionally one or more of the following
features in combination with one another or singly.
Advantageously, the opening leads downstream of the inlet body, the
15 opening being preferably directed in a direction substantially parallel to a longitudinal
direction of the inlet body.
According to one feature the walls comprise an internal wall and an
external wall which are spaced apart from one another at a distance equal at most to 70%
of the maximum diameter of the gasket in radial direction in a longitudinal cross-section of
20 the inlet body to close the housing, and/or
the external wall is inclined at an angle between 15° and 25° relative to
the longitudinal direction.
According to an advantageous embodiment the housing has a
substantially trapezoidal form in a longitudinal cross-section of the inlet body, the opening
25 being located substantially parallel to a base wall of the housing.
According to another advantageous embodiment, the evacuation pipe
traverses an external edge of the annular rim.
Advantageously, at least one portion of the evacuation pipe extends in a
direction substantially parallel to the longitudinal direction.
30 The flow of fluid is thus facilitated in the direction of the stopper.
According to one particular embodiment, at least one portion of the
evacuation pipe is formed by a groove arranged on an external surface of the inlet nozzle.
This part of the evacuation pipe is easy to produce.
According to another feature, the inlet body comprises a sealing valve
accommodated on the inside of the casing, the sealing valve 5 comprising a stopper, the
housing accommodating a gasket, the stopper being in mechanical contact with the gasket
in a closed position of the stopper.
The invention also relates to a fluid injector comprising an inlet body as
defined above.
10 The invention also relates to a turbomachine comprising an injector as
defined above.
Lastly, the invention relates to a method for producing an inlet body as
defined above or an injector as defined above. Themethod of production comprises a step
of inserting a gasket in the housing and deforming the housing to incline the walls towards
15 one another in the direction of the opening.
The housing is thus simple to form, in particular by cold-folding the walls.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is explained in the following description of
embodiments, which are given by way of example and are not restrictive, with reference
20 to the attached drawings in which:
- figure 1 is a partial schematic representation of a fuel injector
of a turbomachine, according to a first embodiment of the invention;
- figure 2 is a functional schematic representation of the
injector according to the first embodiment, in a turbomachine;
25 - figure 3 is a partial schematic representation in longitudinal
cross-section of an inlet body of the injector according to the first embodiment, when the
stopper of the injector is in a closed position;
- figure 4 is a partial schematic representation in longitudinal
cross-section of an inlet body of the injector according to the first embodiment, when the
stopper of the injector is in an open position;
- figure 5 is an enlarged view of detail A shown in figure 3;
- figure 6 is a perspective view of an inlet 5 nozzle of the injector
according to the first embodiment;
- figure 7 is a partial view in elevation of the inlet nozzle of the
injector according to the first embodiment.
10 DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS
Identical, similar or equivalent parts of the different figures have been
given the same reference numerals so as the facilitate the transition fromone figure to the
other.
Figure 1 represents a fuel injector 1 for a turbomachine of an aircraft,
15 according to a preferred embodiment of the invention.
The injector 1 is supplied with fuel from a reservoir 2 of the
turbomachine. At its downstream end, the injector 1 passes through a base of the
combustion chamber 4, in a manner known by a person skilled in the art.
In the present document, the terms “upstream” and “downstream” are
20 used with reference to the flow direction of fuel in the injector 1 in the direction of the
combustion chamber.
The injector 1 comprises an inlet body 3, a central body 5 into which the
inlet body 3 leads, a fixing plate 7 for fixing the injector 1 to a wall of the combustion
chamber, an injection unit 9, and an injector nose 11 located in the proximity of the distal
25 end of the injection unit 9.
The injector 1 comprises, from upstream to downstream, a sealing valve
6, a diaphragm 8 and a metering device 10. The device 10 comprises a first outlet for fuel
10a and a second outlet for fuel 10b different from the first outlet 10a. The first outlet 10a
supplies a primary fuel circuit 12, whereas the second outlet 10b supplies a secondary fuel
circuit 14, designed for the circulation of larger flows in the direction of the combustion
chamber.
The primary circuit 12 comprises a primary swirl 16, from the English “to
swirl”, for rotating the fuel for the purpose of atomisation. The secondary circuit 14
comprises 5 a secondary swirl 17.
The sealing valve 6, the diaphragm8, the metering device 10, the primary
circuit 12 and secondary circuit 14 are arranged on the inside of a casing 13 delimiting the
injector 1.
With joint reference to figures 3 and 4, the inlet body 3 is substantially
10 annular around a longitudinal axis X-X.
In the following description, a direction parallel to the direction of the
longitudinal axis X-X is referred to as the axial direction, a direction orthogonal to the axial
direction is referred to as the radial direction.
The inlet body 3 is delimited by a casing 30 which forms part of the
15 external casing 13 of the injector 1. The inlet body 3 houses the sealing valve 6 on the
interior of the casing 30. Said valve 6 comprises a stopper 20, a spring 28 and an inlet nozzle
50.
The casing 30 comprises an internal surface 31 and an external surface 32
opposite the internal surface 31.
20 The internal surface 31 is substantially cylindrical with a circular crosssection.
It delimits radially to the exterior a housing space 33 of the stopper and a housing
space 35 of the inlet nozzle.
The housing spaces 33 and 35 have substantially the same radius, said
radius corresponds to the distance between the longitudinal axis X-X and the internal
25 surface 31.
The external surface 32 is substantially cylindrical with a circular crosssection,
being concentric to the internal surface 31.
The stopper 20 comprises a body 21, an inner pipe 23 on the inside of the
body 21, and admission pipes 27 which lead into the inner pipe 23.
The stopper 20 is mobile on the inside of the casing 30. It is designed to
be open when the pressure of the fuel is greater than a first threshold. It is designed to be
closed if the pressure of the fuel is lower than this first threshold.
The stopper 20 forms a valve for admitting fuel into the central body 5 of
the injector 1. It is also known as a “inlet valve”. In particular, 5 the stopper 20 is of the “all
or nothing” type: it only has a single stable position in an open position and a single stable
position in a closed position.
The body 21 of the stopper 20 comprises an annular wall 22, a base wall
24 and a contact edge 26.
10 The base wall 24 closes the stopper 20 upstream. Said base wall 24 is
surrounded by the annular contact edge 26.
The contact edge 26 is designed to come into contact with a gasket 56 of
the inlet nozzle 50, in a closed position of the stopper 20.
The annular wall 22 is substantially cylindrical with a circular cross15
section. It delimits with the internal surface 31 an annular housing cavity 29 of the spring
28. Said cavity 29 is delimited in axial direction by a first stop 29a formed by the annular
wall 22 and by a second stop 29b formed by the casing 30.
The spring 28 is a compression spring which is configured to stress the
stopper 20 in the direction of its closed position. The spring 28 is for example a helicoidal
20 spring.
The inner pipe 23 is formed on the inside of the body 21. It is located in
the central part of the body 21. It is used to channel fuel through the stopper 20, in the
direction of the nose of the injector 11.
Each admission pipe 27 has the formof a channel which extends between
25 an intermediate space 37 and the inner pipe 23.
The admission pipes 27 are distributed at angles through the body 21 of
the stopper 20. The admission pipes 27 are each inclined downstream in relation to the
longitudinal direction to facilitate the flow of fuel in the direction of the combustion
chamber.
The intermediate space 37 is delimited radially to the exterior by the
internal surface 31 of the casing.
It is delimited radially to the interior by the stopper 20 in a closed position
of the stopper 20. It is delimited only partially radially to the exterior in an open position of
5 the stopper 20.
The intermediate space 37 is used to connect the inlet nozzle 50 fluidically
to the stopper 20 in an open position of the stopper 20. It has no fluid communication with
the inlet nozzle 50 in a closed position of the stopper 20.
The inlet nozzle 50 comprises an annular body 52 which is traversed at its
10 two opposite ends in axial direction by an inlet 51 and an outlet 57. The inlet nozzle 50
comprises a central pipe 53 which extends from its inlet 51 to its outlet 57 in the
longitudinal direction.
The inlet 51 of the inlet nozzle 50 leads to the exterior of the injector 1.
The outlet 57 of the inlet nozzle 50 leads into the intermediate space 37.
15 The body 52 comprises an annular rim 60 close to the outlet 57 in
longitudinal direction. The annular rim 60 delimits a housing 55, in the form of a recess, for
accommodating a gasket 56. Said gasket 56 is for example an O-ring.
The gasket 56 is designed to come into contact with the contact edge 26
of the stopper 20 in a closed position of the stopper 20, to prevent the flow of fuel between
20 the outlet 57 and the inner pipe 23. The inlet nozzle 50 thus acts as a seat for the stopper
20, in a closed position of the stopper 20, as shown in figure 3.
The gasket 56 has no contact with the contact edge 26, when the stopper
20 is in an open position, as shown in figure 4. In this case, the gasket 56 is at a distance
from the contact edge 26, so that fuel can flow from the outlet 57 of the inlet nozzle 50
25 into the intermediate space 37 before rejoining the inner pipe 23 of the stopper 20.
With reference to figures 5 to 7, the annular rim 60 of the inlet nozzle 50
comprises an upstream edge 62 projecting radially towards the outside of the body 52, an
external edge 64 and an internal edge 66 opposite to the external edge 64.
The upstream edge 62 connects mechanically the internal edge 66 and
30 the external edge 64 upstream of the housing 55. The internal edge 66 and the external
edge 64 both extend downstream from the upstream edge 62. The external edge 64 is
located radially towards the exterior relative to the internal edge 66. The internal edge 66
and the external edge 64 delimit jointly downstream an opening 61 of the housing.
The housing 55 is delimited by a base wall 63 of the upstream edge 62,
an external longitudinal wall 65 of the external edge 64, and 5 an internal longitudinal wall
67 of the internal edge 66. The base wall 63 is opposite the opening 61 in the longitudinal
direction. The two opposite walls 65, 67 each extend between the base wall 63 and the
opening 61.
The housing 55 extends substantially over the whole circumferential
10 length of the annular rim 60, that is substantially over the whole circumferential length of
the inlet nozzle 50.
The housing 55 has a substantially trapezoidal form in the longitudinal
cross-section of the inlet body 3, the opening 61 being substantially parallel to the base
wall 63 of the housing 55.
15 The opening 61 is opened downstream in a direction Y-Y substantially
parallel to a direction of the longitudinal axis X-X.
The external wall 65 is inclined by an angle θ1 of between 15° and 25°
relative to the longitudinal direction X-X.
The internal wall 67 is inclined relative to the longitudinal direction X-X by
20 being spaced apart by a distance d which is equal to atmost 70% of themaximumdiameter
D of the gasket 56 in a radial direction for closing the housing 55.
The walls 65 and 67 are inclined towards one another downstream, in the
direction of the opening 61 of the housing 55. The opening 61 is thus preferably plugged
by the walls 65, 67, which makes it possible to hold the gasket 56 in the housing 55 more
25 effectively.
The annular rim 60 also comprises an evacuation pipe 80 which opens
into the housing 55 through the external wall 65. The evacuation pipe 80 also leads to the
exterior of the inlet nozzle 50.
The evacuation pipe 80 makes it possible to evacuate outside of the
30 housing 55 any fuel which has penetrated the latter and which would be behind the gasket
56. Due to this pipe the fuel in the housing 55 is less at risk of pushing the gasket 56 out of
the housing 55.
With reference to figure 6, the inlet nozzle 50 comprises only two
evacuation pipes 80 which are diametrically opposite one another relative to the
longitudinal 5 axis X-X of the inlet body 3.
With reference more specifically to figure 7, each evacuation pipe 80
comprises a first channel 82, a second channel 84 and a third channel 86.
The first channel 82 extends substantially in radial direction Z1-Z1 from
the external wall 65 to the second channel 84. The second channel 84 extends in a direction
10 Z2-Z2 which is substantially parallel to the longitudinal direction X-X from upstream of the
first channel 82 to the third channel 86. The third channel 86 extends in a direction Z3-Z3
which is substantially radial and substantially parallel to the orientation of the first channel
82.
The second channel 84 has the form of a groove formed in an external
15 surface 59 of the inlet nozzle 50.
The production of the inlet nozzle 3 is explained in the following.
The inlet nozzle 50 is firstly formed so that the external wall 65 is inclined
relative to the angle θ1 and the internal wall 67 is substantially parallel to the longitudinal
direction X-X. The two walls 65, 67 then define between thema larger opening 61 than that
20 of the inlet nozzle 50 which is represented in figure 3.
The gasket 56 is then inserted into its housing 55. The internal edge 66 is
then deformed plastically such that the external wall 65 and the internal wall 67 approach
one another downstream. The opening 61 is then partially sealed, from the approach
towards one another of the walls 65, 67, which makes it possible to hold the gasket 56 in
25 its housing 55. The gasket 56 is then crimped into its housing 55.
The first channel 81 and the third channel 86 are preferably obtained by
piercing the inlet nozzle 50 from the exterior of the inlet nozzle 50. The second channel 84
is formed by a groove of the external surface 59 of the inlet nozzle 50. The evacuation pipe
80 is then easy and relatively inexpensive to produce.
The displacement of the stopper 20 between its closed position
represented in figure 3 to its open position represented in figure 4 is explained below.
In figure 3, the stopper 20 is in a closed position. The pressure of fuel on
the base wall 24 of the stopper is lower than the threshold of opening of the stopper 20,
5 i.e. the first threshold.
The contact edge 26 of the stopper 20 is in mechanical contact with the
gasket 56. The intermediate space 37 is integrally closed radially towards the interior by
the annular wall 22 of the stopper 20. The stopper 20 prevents the fuel arriving with the
flux F1 into the injector 1 from flowing to the intermediate space 37.
10 In figure 4, the stopper 20 is in an open position. The pressure of the fuel
on the base wall 24 of the stopper has become greater than the first threshold.
The contact edge 26 is further away from the inlet nozzle 50, so as to be
without direct mechanical contact with the gasket 56. The intermediate space 37 is only
partially sealed radially towards the interior by the annular wall 22.
15 The fuel which arrives with flux F1 into the injector 1 traverses the central
pipe 53, it flows through the outlet 57 of the inlet nozzle 50 into the intermediate space 37
with flux F2.
The fuel in the intermediate space 37 continues to flow downstream
through the admission pipes 27 into the inner pipe 23 with flux F3. The fuel in the inner pipe
20 23 flows finally downstream with flux F4 in the direction of the metering device 10 of the
injector 1.
Of course, various modifications can be applied by the person skilled in
the art to the invention described above without departing from the scope of the
description of the invention.
25 In particular, the housing 55 can have a different shape other than a
trapezoidal form in longitudinal cross-section of the inlet body 3.
The annular rim 60 and the gasket 56 can extend over only a portion of
the circumferential length of the body 52 of the inlet nozzle 50.
In a similar manner one of the evacuation pipes 80 could extend over a
greater circumferential length of the inlet body 3. The number and the angular distribution
of the evacuation pipes around the longitudinal axis X-X can vary.
The form, the number and inclination of the evacuation channels 82, 84,
86 of each evacuation pipe 80 is also susceptible 5 to variation.
For example, at least one of the evacuation pipes 80 can comprise only a
single channel 82 inclined downstream relative to the longitudinal direction and leading
into the housing 55 through the external wall 65.

WE CLAIM:
1. Inlet body (3) for injecting fluid for a turbomachine, comprising:
a casing (30),
an inlet nozzle (50) housed inside the casing (30) and 5 configured to be used as a
seat for a mobile stopper (20), the inlet nozzle (50) comprising:
a central pipe (53) for the fluid, and
an annular rim (60) surrounding the central pipe (53) and comprising a
housing (55) for a gasket (56),
10 the housing (55) being delimited by a base wall (63), an opening (61)
opposite the base wall (63), and two opposite walls (65, 67) which each extend between
the base wall (63) and the opening (61),
characterised in that the gasket (56) is crimped into the housing (55)
by the walls (65, 67) which are inclined towards one another in the direction of the opening
15 (61),
wherein the annular rim (60) comprises an evacuation pipe (80)
opening into the housing (55) and to the exterior of the inlet nozzle (50), wherein the
evacuation pipe is configured to evacuate fluid out of the housing (55).
20 2. Inlet body (3) according to the preceding claim, wherein the opening
(61) leads downstream to the inlet body (3),wherein the opening (61) is preferably directed
in a direction (Y-Y) which is substantially parallel to a longitudinal direction (X-X) of the inlet
body (3).
25 3. Inlet body (3) according to any of the preceding claims, wherein the
walls (65, 67) are spaced apart by a distance (d) which is equal to more than 70% of the
maximum diameter (D) of the gasket (56) in a radial direction in longitudinal cross-section
of the inlet body (3), to close the housing (55), and/or
wherein the external wall (65) is inclined at an angle (θ1) between 15° and 25°
30 relative to the longitudinal direction (X-X).
4. Inlet body (3) according to any of the preceding claims, wherein the
housing (55) has a substantially trapezoidal form in longitudinal cross-section of the inlet
body (3), wherein the opening (61) is positioned substantially parallel to the base wall (63)
5 of the housing (55).
5. Inlet body (3) according to any of the preceding claims, wherein the
evacuation pipe (80) traverses an external edge (64) of the annular rim (60).
10 6. Inlet body (3) according to any of the preceding claims, wherein at
least a portion of the evacuation pipe (80) extends in a direction (Z2-Z2) substantially parallel
to the longitudinal direction (X-X).
7. Inlet body (3) according to any of the preceding claims, wherein at
15 least one portion of the evacuation pipe (80) is formed by a groove arranged on an external
surface (59) of the inlet nozzle (50).
8. Inlet body (3) according to any of the preceding claims, comprising a
sealing valve (6) accommodated inside the casing (30), wherein the sealing valve (6)
20 comprises a mobile stopper (20), wherein the housing (55) accommodates a gasket (56),
wherein the stopper (20) is in mechanical contact with the gasket (56) in a closed position.
9. Injector (1) of fluid, comprising an inlet body (3) according to any of
the preceding claims.
25
10. Turbomachine comprising an injector (1) according to the
preceding claim.
11. Method for the production of an inlet body (3) according to
30 any of claims 1 to 8 or an injector (1) according to claim 9, comprising:
a step of inserting the gasket (56) into the housing (55), and deforming the housing
(55) so as to incline the walls (65, 67) relative to one another in the direction of the opening
(61).