U.S. patent application number 11/061608 was filed with the patent office on 2008-01-10 for positioning arrangement for components of a pressure vessel and method.
This patent application is currently assigned to Pratt & Whitney Canada Corp.. Invention is credited to Aleksandar Kojovic, Lev Alexander Prociw.
Application Number | 20080006641 11/061608 |
Document ID | / |
Family ID | 36930092 |
Filed Date | 2008-01-10 |
United States Patent
Application |
20080006641 |
Kind Code |
A1 |
Prociw; Lev Alexander ; et
al. |
January 10, 2008 |
Positioning arrangement for components of a pressure vessel and
method
Abstract
The positioning arrangement comprises at least one pair of
complimentary rounded recesses, each recess being provided on the
mating face of the corresponding component. One ball is positioned
between each pair of complementary recesses.
Inventors: |
Prociw; Lev Alexander;
(Elmira, CA) ; Kojovic; Aleksandar; (Oakville,
CA) |
Correspondence
Address: |
OGILVY RENAULT LLP (PWC)
1981 MCGILL COLLEGE AVENUE
SUITE 1600
MONTREAL
QC
H3A 2Y3
CA
|
Assignee: |
Pratt & Whitney Canada
Corp.
|
Family ID: |
36930092 |
Appl. No.: |
11/061608 |
Filed: |
February 22, 2005 |
Current U.S.
Class: |
220/581 |
Current CPC
Class: |
Y10T 403/18 20150115;
F02C 7/20 20130101; F01D 25/24 20130101; Y10T 29/49229
20150115 |
Class at
Publication: |
220/581 |
International
Class: |
F17C 1/00 20060101
F17C001/00 |
Claims
1. A positioning arrangement for a pressure vessel having at least
two adjacent components to be secured together at mating faces, the
arrangement comprising: at least one pair of complementary recesses
forming a rounded space, each recess being provided on the mating
face of one corresponding component, and one ball positioned in the
rounded space of one corresponding pair of complementary
recesses.
2. The positioning arrangement as defined in claim 1, wherein the
rounded space and the corresponding ball are spherical.
3. The positioning arrangement as defined in claim 1, wherein the
pressure vessel comprises a fuel nozzle.
4. The positioning arrangement as defined in claim 1, wherein the
recesses of a same pair are identical.
5. The positioning arrangement as defined in claim 1, wherein the
recesses of a same pair are nonidentical.
6. A method of assembling two adjacent components of a pressure
vessel, the method comprising: machining a first recess in one of
the components; machining a second recess in the other component,
the two recesses being complementary and forming a rounded space
when the two adjacent components are being assembled; and providing
a ball between the two complementary recesses, the ball having an
external shape and size which are substantially identical to an
internal shape and size of the rounded space.
7. The method as defined in claim 6, wherein the rounded space and
the corresponding ball are spherical.
8. The method as defined in claim 6, wherein the pressure vessel
comprises a fuel nozzle.
9. The method as defined in claim 6, wherein the recesses of a same
pair are identical.
10. The method as defined in claim 6, wherein the recesses of a
same pair are nonidentical.
11. A pressure vessel arrangement having at least two adjacent
components to be secured together at mating faces, one of the two
components being a fuel nozzle, the arrangement comprising: at
least one pair of complementary rounded recesses forming a space,
each recess being provided on the mating face of one corresponding
component, and one rounded element snugly fitted in the space of
one corresponding pair of complementary recesses.
12. The positioning arrangement as defined in claim 11, wherein the
rounded element is a spherical ball.
13. The positioning arrangement as defined in claim 11, wherein the
recesses of a same pair are identical.
14. The positioning arrangement as defined in claim 11, wherein the
recesses of a same pair are nonidentical.
Description
TECHNICAL FIELD
[0001] The invention relates generally to a positioning arrangement
for components of a pressure vessel and to a method of positioning
two adjacent components of a pressure vessel.
BACKGROUND OF THE ART
[0002] Pressure vessels are often made of two or more components
that are connected together at some point during manufacturing.
These components generally have mating faces that are provided with
complementary positioning elements to ensure that the components
are perfectly aligned. These positioning elements have a number of
advantages, including being able to ensure that components are
always oriented in accordance with their design. However, pressure
vessels, particularly thin wall pressure vessels, are often prone
to high stress concentration when provided with these positioning
elements.
[0003] In some arrangements, the positioning elements include a
cylindrical pin located at the interface between the two components
being joined together. Cylindrical pins have some limitations and
drawbacks. At first, small cylindrical pins are difficult to handle
during the assembly and pins manufactured with very small
tolerances are expensive. They can also be easily damaged if they
are not handled properly. Then, the arrangements require that two
perfectly colinear cylindrical holes be provided in the adjacent
surfaces. These holes produce stress concentrations due to the
relatively deep holes that are required and the sharp edges
thereof.
[0004] Accordingly, there is a need to provide an improved
positioning arrangement for components of a pressure vessel, and a
method of assembling two adjacent components of a pressure vessel,
with very minimal stress concentrations.
SUMMARY OF THE INVENTION
[0005] It is therefore an object of this invention to provide an
improved positioning arrangement for a pressure vessel, and an
improved method of assembling two adjacent structures of a pressure
vessel.
[0006] In one aspect, the present invention provides a positioning
arrangement for a pressure vessel having at least two adjacent
components to be secured together at mating faces, the arrangement
comprising: at least one pair of complementary recesses forming a
rounded space, each recess being provided on the mating face of one
corresponding component; and one ball positioned in the rounded
space of one corresponding pair of complementary recesses.
[0007] In another aspect, the present invention provides a method
of assembling two adjacent components of a pressure vessel, the
method comprising: machining a first recess in one of the
components; machining a second recess in the other component, the
two recesses being complementary and forming a rounded space when
the two adjacent components are being assembled; and providing a
ball between the two complementary recesses, the ball having an
external shape and size which are substantially identical to an
internal shape and size of the rounded space.
[0008] In another aspect, the present invention provides a pressure
vessel arrangement having at least two adjacent components to be
secured together at mating faces, one of the two components being a
fuel nozzle, the arrangement comprising: at least one pair of
complementary rounded recesses forming a space, each recess being
provided on the mating face of one corresponding component, and one
rounded element snugly fitted in the space of one corresponding
pair of complementary recesses.
[0009] Further details of these and other aspects of the present
invention will be apparent from the detailed description and
figures included below.
DESCRIPTION OF THE DRAWINGS
[0010] Reference is now made to the accompanying figures depicting
aspects of the present invention, in which:
[0011] FIG. 1 schematically shows a generic gas turbine engine to
illustrate an example of a general environment in which the
invention can be used.
[0012] FIG. 2 is a schematic side view showing an example of a
pressure vessel with two different positioning arrangements.
[0013] FIG. 3 is an enlarged schematic cross-section view of an
example of a positioning arrangement in accordance with the present
invention.
[0014] FIG. 4 is an enlarged schematic cross-section view of
another example of a positioning arrangement in accordance with the
present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] FIG. 1 illustrates a gas turbine engine 10 of a type
preferably provided for use in subsonic flight, generally
comprising in serial flow communication a fan 12 through which
ambient air is propelled, a multistage compressor 14 for
pressurizing the air, a combustor 16 in which the compressed air is
mixed with fuel and ignited for generating an annular stream of hot
combustion gases, and a turbine section 18 for extracting energy
from the combustion gases.
[0016] A pressure vessel can be generally defined as a hollow
structure which will be pressurized at one point during its use.
This pressure will generate internal forces in the material of the
structure. Very often, a pressure vessel is made of at least two
components that are secured together using bolts, welds, solders or
any other suitable kind of fasteners. An example of such pressure
vessels is the engine casing of the gas turbine engine 10.
[0017] FIG. 2 schematically illustrates an example of a pressure
vessel 20 having two mating components 22, 24 being secured
together using fasteners (not shown). In this case, the pressure
vessel 20 comprises the walls of a fuel nozzle 100.
[0018] To ensure that the mating components 22, 24 of the pressure
vessel 20 are aligned relative to each other with a very high
degree of accuracy, the present invention uses at least one rounded
element, preferably a spherical ball 30, which is designed to fit
between a pair of opposite complementary recesses 32, 34 machined
in the mating faces of the components 22, 24, which complementary
recesses 32, 34 form together a rounded space in which the ball 30
is set. FIG. 2 also illustrates, on the left side, a pin 102
similar to the ones used in the prior art.
[0019] Preferably, as illustrated, the rounded space and the ball
30 are spherical. Moreover, more than one set of spherical balls 30
and corresponding spherical recesses 32, 34 are preferably provided
and their position is such that during assembly, the components 22,
24 cannot be assembled with a wrong orientation. For instance, the
position of the various balls 30 can be out of alignment with
reference to a line of symmetry of the components 22, 24 for this
purpose.
[0020] The advantages of using balls 30 and corresponding recesses
32, 34 are numerous. First, the balls 30 are available at low cost
with very accurate tolerances. They are available in a large number
of sizes. Balls 30 can be easily manipulated with equipment devised
for ball tacking and they can be easily positioned during the
manufacturing. These balls 30 are more robust than pins, especially
during handling or dropping. Moreover, the rounded recesses 32, 34
in the arrangement produce a far lower stress concentration in
critical areas due to their smooth geometry. This is particularly
advantageous in the case of pressure vessels having a thin wall, in
which conventional positioning arrangements cannot be used because
they can introduce severe stress concentrations.
[0021] If desired, the ball 30 can be partially embedded in a
recess 34 provided in one of the components, which recess 34 is
located deeper in the corresponding component 34 than the opposite
recess 32 of the adjacent component 24. This second component 24
would have only its recess 34 shaped as a segment of the geometric
form, as illustrated in FIG. 4. Both recesses 32, 34 are thus
nonidentical. This is useful, for instance, if one component is
thinner than the other.
[0022] It should be noted that FIGS. 3 and 4 illustrate the
components 22, 24, the recesses 32, 34 and the ball 30 having a
very large tolerance between them. This is only for the purpose of
better illustration. In fact, the outside shape and size of the
ball 30 is substantially identical to the interior shape and size
of the space.
[0023] The above description is meant to be exemplary only, and one
skilled in the art will recognize that changes may be made to the
embodiments described without departing from the scope of the
invention disclosed. For example, the present invention is not
limited to pressure vessels used in a gas turbine engine. The ball
30 and the corresponding recesses 32, 34 can have a rounded shape
which is not necessarily spherical, such as ovoid, ellipsoid,
spheroid, conoid, etc. Still other modifications which fall within
the scope of the present invention will be apparent to those
skilled in the art, in light of a review of this disclosure, and
such modifications are intended to fall within the appended
claims.
* * * * *