U.S. patent application number 15/150870 was filed with the patent office on 2016-11-17 for ejectors.
This patent application is currently assigned to Carrier Corporation. The applicant listed for this patent is Carrier Corporation. Invention is credited to Frederick J. Cogswell, Parmesh Verma, Jinliang Wang.
Application Number | 20160334150 15/150870 |
Document ID | / |
Family ID | 55967180 |
Filed Date | 2016-11-17 |
United States Patent
Application |
20160334150 |
Kind Code |
A1 |
Wang; Jinliang ; et
al. |
November 17, 2016 |
Ejectors
Abstract
An ejector has: a motive flow inlet; a secondary flow inlet; an
outlet; and a motive nozzle. The motive nozzle has an exit. A
motive flow flowpath proceeds through the motive nozzle and joins a
secondary flow flowpath extending from the secondary flow inlet to
form a combined flowpath to the outlet. From upstream to downstream
along the motive flow flowpath, the motive nozzle has: a convergent
section; a throat; a first divergent section commencing within 10%
of a throat-to-exit length and diverging over a first length
(L.sub.D1) of at least 10% of the throat-to-exit length (L.sub.TE);
a second divergent section, the second divergent section diverging
over a second length (L.sub.D2) of at least 10% of the
throat-to-exit length at a shallower angle than the first divergent
section over said first length.
Inventors: |
Wang; Jinliang; (Ellington,
CT) ; Verma; Parmesh; (South Windsor, CT) ;
Cogswell; Frederick J.; (Glastonbury, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Carrier Corporation |
Farmington |
CT |
US |
|
|
Assignee: |
Carrier Corporation
Farmington
CT
|
Family ID: |
55967180 |
Appl. No.: |
15/150870 |
Filed: |
May 10, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62162618 |
May 15, 2015 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25B 2500/01 20130101;
F25B 2341/0012 20130101; F25B 13/00 20130101; F25B 41/00
20130101 |
International
Class: |
F25B 41/00 20060101
F25B041/00; F25B 13/00 20060101 F25B013/00 |
Claims
1. An ejector comprising: a motive flow inlet; a secondary flow
inlet; an outlet; a motive nozzle having an exit; and a motive flow
flowpath proceeding through the motive nozzle and joining a
secondary flow flowpath extending from the secondary flow inlet to
form a combined flowpath to the outlet, wherein from upstream to
downstream along the motive flow flowpath, the motive nozzle has: a
convergent section; a throat; a first divergent section commencing
within 10% of a throat-to-exit length and diverging over a first
length (L.sub.D1) of at least 10% of the throat-to-exit length
(L.sub.TE); and a second divergent section, the second divergent
section diverging over a second length (L.sub.D2) of at least 10%
of the throat-to-exit length at a shallower angle than the first
divergent section over said first length.
2. The ejector of claim 1 wherein, along the motive flow flowpath:
the first divergent section extends at a single first half-angle
(.theta..sub.D1) directly from the throat; and the second divergent
section extends at a single second half-angle (.theta..sub.D2)
directly from the first divergent section.
3. The ejector of claim 2 wherein: the first half-angle is
1.0.degree. to 4.0.degree.; and the second half-angle is
0.7.degree. to 3.0.degree..
4. The ejector of either of claim 2 wherein: the first half-angle
is 1.5.degree. to 2.5.degree.; and the second half-angle is
0.8.degree. to 1.5.degree..
5. The ejector of either of claim 2 wherein: the second half-angle
is 30% to 80% of the first angle.
6. The ejector of either of claim 2 wherein: the second half-angle
is 40% to 60% of the first angle.
7. The ejector of claim 1 wherein: the first length is at least 50%
of the throat-to-exit length; and the second length is at least 15%
of the throat-to-exit length
8. The ejector of claim 1 wherein: the second divergent section
ends within 5% of the throat-to-exit length from the exit.
9. The ejector of claim 1 wherein: the motive nozzle is
metallic.
10. The ejector of claim 1 wherein: a convergent section length
(L.sub.C) is greater than the throat-to-exit length.
11. The ejector of claim 10 wherein: the convergent section length
is at least 110% of the throat-to-exit length.
12. The ejector of claim 1 wherein: there is only a single said
motive flow inlet; there is only a single said secondary flow
inlet; and there is only a single said outlet.
13. The ejector of claim 12 wherein: the motive nozzle is
metallic.
14. A vapor compression system comprising the ejector of claim
1.
15. The vapor compression system of claim 14 further comprising: a
compressor; a first heat exchanger; a second heat exchanger; and a
separator having: an inlet; a liquid outlet; and a vapor outlet; an
expansion device.
16. The vapor compression system of claim 15 further comprising: a
plurality of conduits positioned to define a first flowpath
sequentially through: the compressor; the first heat exchanger; the
ejector from the motive flow inlet through the ejector outlet; and
the separator, and then branching into: a first branch returning to
the compressor; and a second branch passing through the expansion
device and second heat exchanger to the secondary inlet.
17. A method for using the ejector of claim 1 comprising: passing a
motive flow through the motive flow inlet; passing a secondary flow
through the secondary flow inlet; merging the motive flow and the
secondary flow to form a merged flow; and passing the merged flow
through the outlet, wherein: the motive flow reaches a first Mach
number of 0.9 to 1.2 at a downstream end of the first divergent
section; and the motive flow accelerates to a second Mach number of
at least 0.05 greater than the first Mach number in the second
divergent section.
18. The method of claim 17 wherein: the second Mach number is at
least 0.2 greater than the first Mach number.
19. An ejector comprising: a motive flow inlet; a secondary flow
inlet; an outlet; a motive nozzle having an exit; and a motive flow
flowpath proceeding through the motive nozzle and joining a
secondary flow flowpath extending from the secondary flow inlet to
form a combined flowpath to the outlet, wherein from upstream to
downstream along the motive flow flowpath, the motive nozzle has: a
convergent section; a throat; and means for providing an a second
acceleration upstream of the motive nozzle exit that is lower than
a first acceleration downstream of the throat.
20. The ejector of claim 19 wherein the means comprises; a first
divergent section; and a second divergent section, the second
divergent section diverging at a shallower angle than the first
divergent section.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] Benefit is claimed of U.S. Patent Application No.
62/162,618, filed May 15, 2015, and entitled "Ejectors", the
disclosure of which is incorporated by reference herein in its
entirety as if set forth at length.
BACKGROUND
[0002] The present disclosure relates to refrigeration. More
particularly, it relates to ejector refrigeration systems.
[0003] Earlier proposals for ejector refrigeration systems are
found in U.S. Pat. No. 1,836,318 and U.S. Pat. No. 3,277,660. FIG.
1 shows one basic example of an ejector refrigeration system 20.
The system includes a compressor 22 having an inlet (suction port)
24 and an outlet (discharge port) 26. The compressor and other
system components are positioned along a refrigerant circuit or
flowpath 27 and connected via various conduits (lines). A discharge
line 28 extends from the outlet 26 to the inlet 32 of a heat
exchanger (a heat rejection heat exchanger in a normal mode of
system operation (e.g., a condenser or gas cooler)) 30. A line 36
extends from the outlet 34 of the heat rejection heat exchanger 30
to a primary inlet (liquid or supercritical or two-phase inlet) 40
of an ejector 38. The ejector 38 also has a secondary inlet
(saturated or superheated vapor or two-phase inlet) 42 and an
outlet 44. A line 46 extends from the ejector outlet 44 to an inlet
50 of a separator 48. The separator has a liquid outlet 52 and a
gas or vapor outlet 54. A suction line 56 extends from the gas
outlet 54 to the compressor suction port 24. The lines 28, 36, 46,
56, and components therebetween define a primary loop 60 of the
refrigerant circuit 27. A secondary loop 62 of the refrigerant
circuit 27 includes a heat exchanger 64 (in a normal operational
mode being a heat absorption heat exchanger (e.g., evaporator)).
The evaporator 64 includes an inlet 66 and an outlet 68 along the
secondary loop 62. An expansion device 70 is positioned in a line
72 which extends between the separator liquid outlet 52 and the
evaporator inlet 66. An ejector secondary inlet line 74 extends
from the evaporator outlet 68 to the ejector secondary inlet
42.
[0004] In the normal mode of operation, gaseous refrigerant is
drawn by the compressor 22 through the suction line 56 and inlet 24
and compressed and discharged from the discharge port 26 into the
discharge line 28. In the heat rejection heat exchanger, the
refrigerant loses/rejects heat to a heat transfer fluid (e.g.,
fan-forced air or water or other fluid). Cooled refrigerant exits
the heat rejection heat exchanger via the outlet 34 and enters the
ejector primary inlet 40 via the line 36.
[0005] The exemplary ejector 38 (FIG. 2) is formed as the
combination of a motive (primary) nozzle 100 nested within an outer
member 102. The primary inlet 40 is the inlet to the motive nozzle
100. The outlet 44 is the outlet of the outer member 102. The
primary refrigerant flow (motive flow) 103 enters the inlet 40 and
then passes into a convergent section 104 of the motive nozzle 100.
It then passes through a throat section 106 and an expansion
(divergent) section 108 through an outlet (exit) 110 of the motive
nozzle 100. The motive nozzle 100 accelerates the flow 103 and
decreases the pressure of the flow. The secondary inlet 42 forms an
inlet of the outer member 102. The pressure reduction caused to the
primary flow by the motive nozzle helps draw the secondary flow 112
into the outer member. The outer member includes a mixer having a
convergent section 114 and an elongate throat or mixing section
116. The outer member also has a divergent section or diffuser 118
downstream of the elongate throat or mixing section 116. The motive
nozzle outlet 110 is positioned within the convergent section 114.
As the flow 103 exits the outlet 110, it begins to mix with the
flow 112 with further mixing occurring through the mixing section
116 which provides a mixing zone. Thus, respective primary and
secondary flowpaths extend from the primary inlet and secondary
inlet to the outlet, merging at the exit. In operation, the primary
flow 103 may typically be supercritical upon entering the ejector
and subcritical upon exiting the motive nozzle. The secondary flow
112 is gaseous (or a mixture of gas with a smaller amount of
liquid) upon entering the secondary inlet port 42. The resulting
combined flow 120 is a liquid/vapor mixture and decelerates and
recovers pressure in the diffuser 118 while remaining a mixture.
Upon entering the separator, the flow 120 is separated back into
the flows 103 and 112. The flow 103 passes as a gas through the
compressor suction line as discussed above. The flow 112 passes as
a liquid to the expansion valve 70. The flow 112 may be expanded by
the valve 70 (e.g., to a low quality (two-phase with small amount
of vapor)) and passed to the evaporator 64. Within the evaporator
64, the refrigerant absorbs heat from a heat transfer fluid (e.g.,
from a fan-forced air flow or water or other liquid) and is
discharged from the outlet 68 to the line 74 as the aforementioned
gas.
[0006] Use of an ejector serves to recover pressure/work. Work
recovered from the expansion process is used to compress the
gaseous refrigerant prior to entering the compressor. Accordingly,
the pressure ratio of the compressor (and thus the power
consumption) may be reduced for a given desired evaporator
pressure. The quality of refrigerant entering the evaporator may
also be reduced. Thus, the refrigeration effect per unit mass flow
may be increased (relative to the non-ejector system). The
distribution of fluid entering the evaporator is improved (thereby
improving evaporator performance). Because the evaporator does not
directly feed the compressor, the evaporator is not required to
produce superheated refrigerant outflow. The use of an ejector
cycle may thus allow reduction or elimination of the superheated
zone of the evaporator. This may allow the evaporator to operate in
a two-phase state which provides a higher heat transfer performance
(e.g., facilitating reduction in the evaporator size for a given
capability).
[0007] The exemplary ejector may be a fixed geometry ejector or may
be a controllable ejector. FIG. 2 shows controllability provided by
a needle valve 130 having a needle 132 and an actuator 134. The
actuator 134 shifts a tip portion 136 of the needle into and out of
the throat section 106 of the motive nozzle 100 to modulate flow
through the motive nozzle and, in turn, the ejector overall.
Exemplary actuators 134 are electric (e.g., solenoid or the like).
The actuator 134 may be coupled to and controlled by a controller
140 which may receive user inputs from an input device 142 (e.g.,
switches, keyboard, or the like) and sensors (not shown). The
controller 140 may be coupled to the actuator and other
controllable system components (e.g., valves, the compressor motor,
and the like) via control lines 144 (e.g., hardwired or wireless
communication paths). The controller may include one or more:
processors; memory (e.g., for storing program information for
execution by the processor to perform the operational methods and
for storing data used or generated by the program(s)); and hardware
interface devices (e.g., ports) for interfacing with input/output
devices and controllable system components.
[0008] A further variation is shown in Ogata et al. U.S. Pat. No.
8,523,091, Sep. 3, 2013. Ogata et al. shows an ejector with a
motive nozzle having a convergent section leading to at least three
distinct divergent sections. An intermediate section of the three
has a shallower taper than the other two sections.
SUMMARY
[0009] One aspect of the disclosure involves an ejector comprising:
a motive flow inlet; a secondary flow inlet; an outlet; and a
motive nozzle. The motive nozzle has an exit. A motive flow
flowpath proceeds through the motive nozzle and joins a secondary
flow flowpath extending from the secondary flow inlet to form a
combined flowpath to the outlet. From upstream to downstream along
the motive flow flowpath, the motive nozzle has: a convergent
section; a throat; a first divergent section commencing within 10%
of a throat-to-exit length and diverging over a first length of at
least 10% of the throat-to-exit length (L.sub.TE); a second
divergent section, the second divergent section diverging over a
second length (LD2) of at least 10% of the throat-to-exit length at
a shallower angle than the first divergent section over said first
length.
[0010] In one or more embodiments of the other embodiments, along
the motive flow flowpath: the first divergent section extends at a
single first half-angle (.theta..sub.D1) directly from the throat;
and the second divergent section extends at a single second
half-angle (.theta..sub.D2) directly from the first divergent
section.
[0011] In one or more embodiments of the other embodiments, the
first half-angle is 1.0.degree. to 4.0.degree.; and the second
half-angle is 0.7.degree. to 3.0.degree..
[0012] In one or more embodiments of the other embodiments, the
first half-angle is 1.5.degree. to 2.5.degree.; and the second
half-angle is 0.8.degree. to 1.5.degree..
[0013] In one or more embodiments of the other embodiments, the
second half-angle is 30% to 80% of the first angle.
[0014] In one or more embodiments of the other embodiments, the
second half-angle is 40% to 60% of the first angle.
[0015] In one or more embodiments of the other embodiments, the
first length is at least 50% of the throat-to-exit length; and the
second length is at least 15% of the throat-to-exit length
[0016] In one or more embodiments of the other embodiments, the
second divergent section ends within 5% of the throat-to-exit
length from the exit.
[0017] In one or more embodiments of the other embodiments, a
convergent section length (L.sub.C) is greater than the
throat-to-exit length.
[0018] In one or more embodiments of the other embodiments, the
convergent section length is at least 110% of the throat-to-exit
length.
[0019] In one or more embodiments of the other embodiments, the
motive nozzle is metallic.
[0020] In one or more embodiments of the other embodiments: there
is only a single said motive flow inlet; there is only a single
said secondary flow inlet; and there is only a single said
outlet.
[0021] Another aspect of the disclosure involves a method for using
the ejector. The method comprises: passing a motive flow through
the motive flow inlet; passing a secondary flow through the
secondary flow inlet; merging the motive flow and the secondary
flow to form a merged flow; and passing the merged flow through the
outlet. The motive flow reaches a first Mach number of 0.9 to 1.2
at a downstream end of the first divergent section. The motive flow
accelerates to a second Mach number of at least 0.05 greater than
the first Mach number in the second divergent section.
[0022] In one or more embodiments of the other embodiments, the
second Mach number is at least 0.2 greater than the first Mach
number.
[0023] In one or more embodiments of the other embodiments, a vapor
compression system comprises the ejector.
[0024] In one or more embodiments of the other embodiments, the
vapor compression system further comprises: a compressor; a first
heat exchanger; a second heat exchanger; and a separator having: an
inlet; a liquid outlet; and a vapor outlet; an expansion
device.
[0025] In one or more embodiments of the other embodiments, the
vapor compression system further comprises: a plurality of conduits
positioned to define a first flowpath sequentially through: the
compressor; the first heat exchanger; the ejector from the motive
flow inlet through the ejector outlet; and the separator, and then
branching into: a first branch returning to the compressor; and a
second branch passing through the expansion device and second heat
exchanger to the secondary inlet.
[0026] Another aspect of the disclosure involves an ejector
comprising: a motive flow inlet; a secondary flow inlet; an outlet;
and a motive nozzle. The motive nozzle has an exit. A motive flow
flowpath proceeds through the motive nozzle and joins a secondary
flow flowpath extending from the secondary flow inlet to form a
combined flowpath to the outlet. From upstream to downstream along
the motive flow flowpath, the motive nozzle has: a convergent
section; a throat; and means for providing a second acceleration
upstream of the exit lower than a first acceleration downstream of
the throat.
[0027] In one or more embodiments of the other embodiments, the
means comprises a first divergent section and a second divergent
section at a shallower angle than the first divergent section.
[0028] The details of one or more embodiments are set forth in the
accompanying drawings and the description below. Other features,
objects, and advantages will be apparent from the description and
drawings, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a schematic view of a prior art ejector
refrigeration system.
[0030] FIG. 2 is an axial sectional view of a prior art
ejector.
[0031] FIG. 3 is an axial sectional view of a second ejector.
[0032] FIG. 4 is an axial sectional view of a motive nozzle of the
second ejector.
[0033] Like reference numbers and designations in the various
drawings indicate like elements.
DETAILED DESCRIPTION
[0034] FIG. 3 shows a modified ejector 200 that may replace the
ejector of FIG. 2 in the system of FIG. 1. However, the
modification as described below may apply to other ejectors used in
other vapor compression systems. The ejector 200 may represent a
modification of a baseline ejector differing in terms of the
interior of the motive nozzle 202. Various features that may be
shared with the baseline FIG. 2 ejector are referenced with
corresponding numerals and are not necessarily separately
discussed.
[0035] As with the baseline ejector, the nozzle 200 and its
passageway comprise a convergent section 206 leading to a throat
208. The exemplary throat is a single longitudinal location (zero
length). Alternative throats may be represented by a cylindrical
cross-section (e.g., a right circular cylinder) of non-zero length.
Downstream of the throat (e.g., immediately/directly downstream) is
a first divergent section 210. An exemplary first divergent section
extends over a length L.sub.D1. An exemplary first divergent
section has a single angle of diversion (shown as a half-angle
.theta..sub.D1).
[0036] A second divergent section 212 is downstream of the first
divergent section 210. The second divergent section is less
divergent (smaller magnitude of an angle between the surface and
the centerline or axis of the passageway) than the first divergent
section. The second divergent section may have a single constant
divergence angle (shown as half-angle .theta..sub.D2) over a length
L.sub.D2. The second divergent section can extend directly from the
first divergent section to the exit so that the two lengths equal
the throat-to-exit length L.sub.TE. For throats of non-zero length,
L.sub.TE may be measured from the downstream end of the throat.
With the addition of variations such as bevels and chamfers, the
length of the two may sum to greater than or equal to 90% of
L.sub.TE, for example at least 95% or at least 98%.
[0037] In some embodiments, the angle .theta..sub.D1 is from
0.5.degree. to 5.0.degree., or 1.0 to 4.0.degree., or 1.5.degree.
to 2.5.degree., or 2.0.degree.. The angle .theta..sub.D1 may be
selected to provide a rapid expansion/vaporization of the motive
flow.
[0038] In some embodiments, the angle .theta..sub.D2 is from
0.3.degree. to 4.0.degree., or 0.7.degree. to 3.0.degree., or
0.8.degree. to 1.5.degree., or 1.0.degree. to 1.3.degree.. This may
be selected to tailor the exit flow for improved mixing with the
secondary flow. In some embodiments, the angle .theta..sub.D2 is
from 40% to 60% of .theta..sub.D1, or 40% to 70% of .theta..sub.D1,
or 30% to 80% of .theta..sub.D1.
[0039] In some embodiments, the angle L.sub.D1 is 5% to 80% of
L.sub.TE, or 10% to 60%, or 20% to 40%. This may be selected to
limit the Mach number of material flowing through the first
divergent section 210 (e.g., the downstream end thereof forming a
junction with the second divergent section 212) to a range of 0.9
to 1.2. The Mach number in the second divergent section 212 will be
higher (e.g., 1.0 to 2.0 at the exit 110 and at least 0.050 higher
than in the first divergent section (e.g., at the downstream end of
the first divergent section), or at least 0.10 higher, or at least
0.20 higher).
[0040] In some embodiments, the angle L.sub.D2 is 20% to 95% of
L.sub.TE, or 40% to 90%, or 60% to 80%. This may be selected to
avoid flow separation and avoid a shock inside the nozzle.
[0041] In operation, high pressure (e.g., transcritical or liquid
state), low velocity (e.g., Mach number of 0.01 to 0.1), flow
enters the motive nozzle. It then undergoes acceleration to a Mach
number of 0.8 to 1.0 near the throat (minimum cross-section)
location or region. Thereafter, the flow further accelerates in the
first divergent section to a Mach number of 0.9 to 1.2 at the end
of the first divergent section. The flow further accelerates in the
second divergent section to a Mach number of 1.0 to 2.0 at the exit
of the second divergent section. The Mach number of the flow in the
second divergent section (e.g., at the end of the second divergent
section) is at least 0.05 higher than that in the first divergent
section (e.g., at the end of the first divergent section). In
various implementations, this may offer an advantageous combination
of smooth flow acceleration and cost reduction (minimizing
divergent angles and optimal choice of angle relationships) because
faster acceleration is first targeted in the first divergent
section using a larger angle (than the second divergent section)
and slower acceleration (with the highest Mach number) is targeted
in the second divergent section with a smaller angle (than the
first divergent section).
[0042] Relative to a baseline nozzle with a single angle of
divergence, one or more advantages may be present in some
particular implementations. For example, the first divergent
section may quickly expand and vaporize the motive flow; whereas
the second divergent section controls the fluid exiting angle and
velocity which can improve the mixing process in the mixer.
[0043] Relative to more complex configurations such as the third
figure of Ogata et al. there may also be one or more of several
advantages in some particular implementations. One notable
advantage is that an implementation with just two divergent angles
may be easier to align the sections when manufacturing (e.g., allow
for easier centering of the axes of the throat, the first divergent
section, and/or the second divergent section relative to any one of
the preceding when machining). Second, reduced overall length may
correspondingly reduce material cost and/or reduce costs of the
needle and its actuator if present.
[0044] A further potential advantage in some particular
implementations relative to the Ogata et al. configuration involves
the relationship of the convergent section length L.sub.C to the
total divergent section length or throat-to-exit length L.sub.TE.
Whereas Ogata et al. shows an extremely short convergent length,
the present exemplary L.sub.C may be larger than L.sub.D1 and
L.sub.D2 individually and combined. For example, exemplary L.sub.C
may be at least 80% of L.sub.TE, at least, 100% of L.sub.TE, or at
least 105% of L.sub.TE.This relatively long convergent section can
provide benefits of smoothed flow transition in some particular
implementations. For example, flow through the convergent section
may have a Mach number of 0.1 to 1.0 (e.g., entering the convergent
section having a Mach number of 0.10 and exiting the convergent
section having a Mach number of 0.9 to 1.0), this relatively longer
transition can provide smother flow acceleration and thus reduced
flow separation and hence reduced frictional or shear losses. The
losses can be more significant at higher Mach numbers (e.g., at
Mach numbers of 0.5 to 1.0). A shorter convergent section may have
a similar change in Mach number over a shorter length, thus
suffering greater flow separation frictional and/or shear losses. A
relatively longer convergent section can be particularly beneficial
for embodiments having needles extending into the convergent
section. The presence of the needle can cause additional flow
disturbances in the convergent section as the flow is
accelerated.
[0045] In other variations, additional features such as those of
other baseline nozzles may be present. For example, a non-zero
length throat is noted above. Furthermore, the use of various
needles and their actuators are within the scope of the present
disclosure and their use without does not depart from the spirit of
the present disclosure.
[0046] Materials and manufacturing techniques commonly used for
ejectors and vapor compression systems may be used. Motive nozzles
can include metal (e.g., steel, aluminum, copper, titanium, or a
combination including at least one of the foregoing), plastic, or a
combination comprising at least one of the foregoing. Manufacturing
techniques can include machining (e.g., lathe turning of exterior
surface portions of the motive nozzle and drilling or
electro-discharge machining (EDM) of the central passageway from
motive nozzle inlet to motive nozzle exit). Such techniques can
yield a passageway (e.g., throat, convergent section and/or
divergent section) centered on the nozzle axis (e.g., of circular
cross-section). Exemplary forming of the passageway comprises
end-to end drilling. This may define the throat diameter. Then the
divergent section may be formed by EDM (e.g., wire EDM). An
exemplary EDM of the convergent section involves using a conical
tool (electrode) shaped to the profile of the convergent section
Similarly, one or more electrodes may be used to EDM the divergent
sections (e.g., two conical electrodes corresponding to the
respective divergent sections). In an embodiment, the ejector can
be formed in an additive manufacturing process such as, but not
limited to, powdered metal sintering, direct deposition, and the
like.
[0047] The use of "first", "second", and the like in the
description and following claims is for differentiation within the
claim only and does not necessarily indicate relative or absolute
importance or temporal order. Similarly, the identification in a
claim of one element as "first" (or the like) does not preclude
such "first" element from identifying an element that is referred
to as "second" (or the like) in another claim or in the
description.
[0048] One or more embodiments have been described. Nevertheless,
it will be understood that various modifications may be made. For
example, when applied to an existing basic system, details of such
configuration or its associated use may influence details of
particular implementations. Accordingly, other embodiments are
within the scope of the following claims.
* * * * *