U.S. patent application number 16/155021 was filed with the patent office on 2020-04-09 for integrated rotary positive-displacement machinery.
This patent application is currently assigned to HI-BAR BLOWERS, INC.. The applicant listed for this patent is HI-BAR BLOWERS, INC.. Invention is credited to Paul Xiubao HUANG, Sean William YONKERS.
Application Number | 20200109713 16/155021 |
Document ID | / |
Family ID | 70052107 |
Filed Date | 2020-04-09 |
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United States Patent
Application |
20200109713 |
Kind Code |
A1 |
HUANG; Paul Xiubao ; et
al. |
April 9, 2020 |
INTEGRATED ROTARY POSITIVE-DISPLACEMENT MACHINERY
Abstract
Integrated rotary positive-displacement machinery, for example
compressors and/or vacuum pumps, include a compressor core equipped
with at least one shunt pulsation trap and at least one absorptive
silencer integrated together along with other compressor components
(such as inlet/outlet pulsation dampeners, gas filters, safety
valves, etc.) into a unit or package with a reduced pulsation,
noise, energy consumption, and size and weight. Some embodiments
further include at least one 4-way valve and corresponding piping
so that the same positive-displacement machine can be operated to
selectively provide vacuum and pressure by operation of the valve
and piping.
Inventors: |
HUANG; Paul Xiubao;
(Fayetteville, GA) ; YONKERS; Sean William;
(Peachtree City, GA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HI-BAR BLOWERS, INC. |
Fayetteville |
GA |
US |
|
|
Assignee: |
HI-BAR BLOWERS, INC.
Fayetteville
GA
|
Family ID: |
70052107 |
Appl. No.: |
16/155021 |
Filed: |
October 9, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04C 29/063 20130101;
F04C 18/126 20130101; F04C 18/12 20130101; F04C 29/12 20130101;
F04C 29/0035 20130101; F04C 18/18 20130101 |
International
Class: |
F04C 29/00 20060101
F04C029/00; F04C 18/18 20060101 F04C018/18; F04C 29/12 20060101
F04C029/12 |
Claims
1. An integrated rotary positive-displacement machine (IRPDC),
comprising: a compressor core having a compressor cavity having a
gas flow suction port and a gas flow discharge port, and at least
two rotors mounted in the compressor cavity and driven in a
compression phase to reduce the compressor cavity gas volume and
propel gas flow from the suction port to the discharge port; a
shunt pulsation trap including a trap chamber positioned adjacent
to the compressor cavity, at least one pulsation dampener
positioned within the trap chamber, at least one trap inlet
branching off from the compressor cavity into the pulsation trap
chamber, and at least one trap outlet communicating with the
compressor discharge port; and an integrated absorptive silencer
including at least one folded flow channel and noise-absorbing
material, with the at least one folded flow channel interfaced
directly with at least one of the suction or discharge ports of the
compressor core and at one end and open to atmosphere at the other
end, wherein in operation the IRPDC achieves both low-frequency gas
pulsation and high-frequency noise reduction at source and improves
compressor off-design efficiency without using a traditional serial
pulsation dampener.
2. The IRPDC as claimed in claim 1, wherein the at least one flow
channel of the absorptive dampener has a folded configuration with
at least one turn equal to or larger than 90 degrees.
3. The IRPDC as claimed in claim 1, wherein the at least one flow
channel of the absorptive dampener has a folded shape and at least
one said wall that is perforated and lined with the noise-absorbing
material.
4. The IRPDC as claimed in claim 1, wherein the at least one flow
channel of the absorptive dampener has parallel walls with no
sudden change in cross-sectional area.
5. The IRPDC as claimed in claim 4, wherein the at least one flow
channel interfaces directly with at least one of said flow ports of
said compressor core, and wherein the at least one flow channel and
the interfaced flow port of said compressor have a same
cross-sectional shape.
6. The IRPDC as claimed in claim 4, wherein the integrated
absorptive silencer includes a flow divider where the at least one
flow channel interfaces directly with the interfaced flow port of
said compressor core, wherein said at least one flow channel is
divided into two flow channels by the divider.
7. The IRPDC as claimed in claim 6, wherein said two flow channels
meet again with a flow channel length difference of 1/4
wavelength.
8. The IRPDC as claimed in claim 6, wherein said flow channel
divider has a protruding lip.
9. The IRPDC as claimed in claim 1, wherein said absorptive
dampener is separated from said compressor core by an inlet
dampener.
10. The IRPDC as claimed in claim 9, wherein the inlet dampener has
at least one layer of perforated and curved surface.
11. An integrated rotary positive-displacement machine (IRPDC),
comprising: a compressor core having a gas flow suction port, a gas
flow discharge port, and a compressor cavity formed with at least
two rotors mounted inside said compressor cavity and driven in a
compression phase to reduce said compressor cavity gas volume and
propel gas flow from said suction port to said discharge port; a
shunt pulsation trap comprising a trap chamber positioned adjacent
to said compressor cavity, at least one pulsation dampener
positioned within said trap chamber, at least one trap inlet
branching off from said compressor cavity into said pulsation trap
chamber, and at least one trap outlet communicating with
atmosphere; and at least one integrated absorptive silencer
comprising at least one folded flow channel and noise-absorbing
material interfaced directly with at least one of said trap outlets
and/or the discharge port of said compressor core on one end and/or
with atmosphere on the other end; wherein in operation said IRPDC
achieves both low-frequency gas pulsation and high-frequency noise
reduction at source and improves compressor off-design efficiency
without using at least one traditional serial pulsation
dampener.
12. The IRPDC as claimed in claim 11, wherein the at least one flow
channel of the absorptive dampener has a folded configuration with
at least one turn equal to or larger than 90 degrees.
13. The IRPDC as claimed in claim 11, wherein the at least one flow
channel of the absorptive dampener has at least one said wall that
is perforated and lined with the noise-absorbing material.
14. The IRPDC as claimed in claim 11, wherein the at least one flow
channel interfaces directly with at least one of said flow ports of
said compressor core, and wherein the at least one flow channel and
the interfaced flow port of said compressor have a same
cross-sectional shape.
15. The IRPDC as claimed in claim 11, wherein the integrated
absorptive silencer includes a flow divider where the at least one
flow channel interfaces directly with the interfaced flow port of
said compressor core, wherein said at least one flow channel i is
divided into two flow channels by the divider.
16. An integrated rotary positive-displacement machine (IRPDC),
comprising: a compressor core having a gas flow suction port, a gas
flow discharge port, and a compressor cavity formed with at least
two rotors mounted inside said compressor cavity and driven in a
compression phase to reduce said compressor cavity gas volume and
propel gas flow from said suction port to said discharge port; a
shunt pulsation trap including a trap chamber positioned adjacent
to the compressor cavity, at least one trap inlet branching off
from the compressor cavity into the pulsation trap chamber, and at
least one trap outlet communicating with the compressor discharge
port; and a first 4-way valve located in front of the compressor
core and having four ports, wherein with the first 4-way valve set
for a vacuum mode a system port connecting to an external system is
connected with the compressor core suction port and an atmosphere
port connecting to atmosphere is connected with the compressor core
discharge port, and wherein the first 4-way valve can be switched
to a pressure mode with the system now connecting with the
compressor core discharge port through the SPT and the atmosphere
port now connecting with the compressor core suction port, wherein
in operation said IRPDC achieves a dual-purpose machine for both
pressure and vacuum functionality.
17. The IRPDC as claimed in claim 16, wherein at least one
pulsation dampener is positioned within the trap chamber.
18. The IRPDC as claimed in claim 16, further comprising an
integrated absorptive silencer comprising at least one folded flow
channel and noise-absorbing material interfaced directly with at
least one of said trap outlets and/or the discharge port of said
compressor core.
19. The IRPDC as claimed in claim 16, wherein the shunt pulsation
trap outlet communicates with atmosphere by a second 4-way valve
having four ports, wherein the second 4-way valve can be switched
to a deep vacuum mode corresponding to the first 4-way valve set
for the vacuum mode when it is open to atmosphere, and switched to
the pressure mode corresponding to the first 4-way valve set for
the pressure mode when it is closed to atmosphere.
20. The IRPDC as claimed in claim 19, further comprising an
integrated absorptive silencer comprising at least one folded flow
channel and noise-absorbing material interfaced directly with at
least one of said trap outlets and/or the discharge port of said
compressor core.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to the field of
positive-displacement machinery, and more particularly to improved
noise reduction for positive-displacement gas-transfer
machinery.
BACKGROUND
[0002] Conventional rotary positive-displacement compressors
(RPDCs) include compressors and vacuum pumps of several types such
as Roots, claw, sliding-vane, screw, and scroll machinery, as shown
in FIG. 1. RPDCs use various types of rotary positive-displacement
mechanisms housed in a compressor core to compress a wide range of
gases. RPDCs are widely used in many different industries,
including chemical and petrochemical, food processing, power
generation, natural and process gas applications, refrigeration,
and in vapor-recovery services. When operating at off-design
conditions such as over-compression or under-compression, they
inherently generate high amplitude pulsating pressures (e.g., up to
180-200 dB), and to address this prior-art RPDCs typically include
a reactive or combination-type dampener or silencer (see, e.g.,
FIGS. 2b, 2c, and 2e) configured in series after discharge to
suppress both the low-frequency gas pulsations and the
high-frequency noises. However, this serial dampening scheme
suffers a sizable back-pressure loss or requires a considerably
larger-sized dampener to reduce this loss. Growing global demand to
simultaneously meet higher efficiency, smaller size, and lower
noise for these systems is conflicting with the governing rule of
conventional serial dampening (see, e.g., FIG. 2a) employed for the
past 100 years: more noise reduction equates to more back-pressure
loss and larger size.
[0003] Conventional shunt pulsation trap (SPT) technology attempts
to address this problem by tackling the inherent pressure pulses
before discharge, for example as shown in FIG. 3a. Details of SPT
technology are disclosed for example in several co-owned patents
(U.S. Pat. Nos. 9,140,260; 9,151,292; 9,140,261; 9,243,557;
9,551,342; and 9,732,754, all of which are hereby incorporated
herein by reference). Conventional SPT technology is very effective
in suppressing the low-frequency pressure pulsation levels by at
least about 10-fold (see, e.g., FIG. 3b) and reducing the energy
consumption by about 5-16% (see, e.g., FIG. 3c) due to the
elimination of the back-pressure loss inherent with serial
dampening. The dampener size of conventional SPTs can also be
reduced by at least about 5-fold by integrating the SPT with the
compressor core (see, e.g., FIG. 3b). However, current SPT
technology does not sufficiently reduce the high-frequency noises
at the same time.
[0004] Conventional absorptive silencers are very effective in
controlling high-frequency noises by lining perforated flow-channel
walls with sound-absorbing materials, as shown in FIG. 2d.
Industrial absorptive silencers are typically constructed in a
cylindrical shape and connected to an RPDC discharge flange that
often results in a considerably larger cross-sectional size than
the RPDC itself. Typically, additional RPDC components are
included, such as filters, valves, process control systems, and
related plumbing, which further increases not only the package
size, but also the weight and cost of the system. The challenge is
to simultaneously reduce gas pulsation, noise, energy, and size for
RPDC machinery.
[0005] For mobile applications such as liquid tank haulers, it is
often required to have both vacuum to load and pressure to unload
the system. Typically, these systems include two
positive-displacement machines, with one operating as a vacuum pump
and the other operating as a compressor, with corresponding
noise-reduction systems that are bulky and costly. The challenge
here is to use one small system to do both vacuum and pressure
duties while simultaneously reducing gas pulsation, noise, space,
and weight, with the space and weight factors being particularly
important for mobile applications.
[0006] Accordingly, it can be seen that needs exist for improved
positive-displacement machinery. It is to the provision of
solutions to these and other problems that the present invention is
primarily directed.
SUMMARY
[0007] Integrated rotary positive-displacement machinery, for
example compressors and/or vacuum pumps, include a compressor core
equipped with at least one shunt pulsation trap and at least one
absorptive silencer integrated together along with other compressor
components (such as inlet/outlet pulsation dampeners, gas filters,
safety valves, etc.) into a unit or package with a reduced size and
weight. Some embodiments further include at least one 4-way valve
and corresponding piping so that the same positive-displacement
machine can be operated to selectively provide vacuum and pressure
by operation of the valve and piping.
[0008] The specific techniques and structures employed to improve
over the drawbacks of the prior devices and accomplish the
advantages described herein will become apparent from the following
detailed description of example embodiments and the appended
drawings and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows a classification chart of prior-art rotary
positive-displacement compressors and vacuum pumps (RPDC).
[0010] FIG. 2a is two flow charts of the phases of a prior-art
compression cycle with serial dampening, showing under compression
(top flow chart) and over compression (bottom flow chart).
[0011] FIG. 2b is a series of perspective views of a prior-art
screw compressor showing the phases of the prior-art compression
cycle with serial dampening generally corresponding to FIG. 2a.
[0012] FIG. 2c is two perspective views, in partial cutaway, of two
prior-art serial reactive silencers.
[0013] FIG. 2d is a perspective view, in partial cutaway, of a
prior-art serial absorptive silencer.
[0014] FIG. 2e is a perspective view, in partial cutaway, of a
prior-art serial combination reactive/absorptive silencer.
[0015] FIG. 3a is two flow charts of the phases of a prior-art
compression cycle with a shunt pulsation trap, showing
under-compression (top flow chart) and over-compression (bottom
flow chart).
[0016] FIG. 3b is a cross-sectional view of a prior-art Roots
compressor with a shunt pulsation trap, showing the triggering
moment at the trap inlet suddenly opening.
[0017] FIG. 3c is a P-V diagram of serial dampening (with back
pressure) and shunt pulsation trapping (without back pressure)
compared to show work savings.
[0018] FIG. 4a is two flow charts of the phases of a compression
cycle of an integrated rotary positive-displacement compressor
(IRPDC) with a shunt pulsation trap (SPT) and an integrated
absorptive silencer (IAS) according to a first example embodiment
of the present invention, showing under-compression (top flow
chart) and over-compression (bottom flow chart).
[0019] FIG. 4b is a perspective cross-sectional view of an IRPDC
with an SPT and an IAS according to FIG. 4a (top flow chart),
showing jet IAS and discharge IAS in a vacuum mode.
[0020] FIG. 4c1 is a cross-sectional view of the IRPDC with the SPT
and the IAS of FIG. 4a.
[0021] FIG. 4c2 is a perspective cross-sectional view of the IAS of
the IRPDC with the SPT and the IAS of FIG. 4b, showing exemplary
details of perforated plate and sound absorptive materials.
[0022] FIG. 4c3 is a cross-sectional view of an IAS of an IRPDC
with an SPT and an IAS according to a second example embodiment of
the present invention.
[0023] FIG. 4d is a cross-sectional view of an IRPDC with an SPT
and an IAS according to a third example embodiment of the present
invention, showing jet IAS and inlet IAS in a pressure mode.
[0024] FIG. 4e is a cross-sectional view of an IRPDC with an SPT
and an IAS according to a fourth example embodiment of the present
invention, showing jet IAS and discharge IAS in a deep vacuum
mode.
[0025] FIG. 5a is a perspective view of an IRPDC with an SPT and an
IAS according to a fifth example embodiment of the present
invention, additionally including a 4-way valve to provide for
operation in either a pressure mode or a vacuum mode in an
integrated vacuum and pressure (IVP) arrangement.
[0026] FIG. 5b is a cross-sectional view of the IRPDC with the SPT,
the IAS, and the 4-way valve of FIG. 5a, showing operation in the
pressure mode.
[0027] FIG. 5c shows the IRPDC with the SPT, the IAS, and the 4-way
valve of FIG. 5a in operation in the vacuum mode.
[0028] FIG. 5d is a cross-sectional view of an IRPDC with an SPT,
an IAS, and two 4-way valves in an integrated vacuum and pressure
(IVP) arrangement according to a sixth example embodiment of the
present invention, showing operation in the deep vacuum mode.
[0029] FIG. 5e shows the IRPDC with the SPT, the IAS, and the two
4-way valves of FIG. 5d in operation in the pressure mode.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS
[0030] Generally described, the present invention relates to
integrated rotary positive-displacement compressors (IRPDCs) with
shunt pulsation traps (SPTs) and integrated absorptive silencers
(IASs) to reduce low-frequency gas pulsations and high-frequency
noise while maintaining a smaller size and not suffering back
pressure loss. In some embodiments, the SPT is parallel-connected
with a cavity of the compressor and is able to control the
large-amplitude low-frequency pulses by trapping waves and
converting one big low-frequency pulse jet into multiple
smaller-frequency jets that generate higher-frequency noises. And
the IAS is serially connected with the compressor cavity, absorbing
the high-frequency noises plus those generated due to lobe meshing
and leftover from the SPT. The SPT and the IAS are combined in a
configuration to achieve adequate dampening without suffering
noticeable back pressure loss. The IAS can interface directly and
seamlessly with a rectangular cross-sectional shape of a compressor
core inlet/outlet while folding its flow path in a conforming shape
to an exterior shape of the compressor core. Generally, the IAS
provides about the same noise-absorptive effectiveness as a
conventional silencer by maintaining about the same flow velocity
and total area of absorbing surface (perforated surface with
absorptive material inside) that the gas-flow passes.
[0031] There are several additional advantages provided by the
IRPDCs with the SPTs and the IASs. First of all, added turns to the
gas-flow path of the IAS block the direct path of the sound
propagation to reduce the noise, the while the effect on back
pressure loss is minimum. Secondly, the IAS has a modified
cross-sectional shape that eliminates the cross-sectional shape
transition from a rectangular to a circular flange in a traditional
cylindrical shaped silencer to help reduce the back-pressure loss
and material consumption. And thirdly, the IAS provides for a
reduced total space (also called installation space) that is
occupied.
[0032] Typical embodiments of the IRPDCs with the SPTs and the IASs
have three modes of operation: vacuum mode, pressure mode, and deep
vacuum mode. The vacuum mode is an application with the inlet port
of the compressor core connected to a process while the outlet port
of the compressor core is connected to the IAS through the SPT
which in turn is open to atmosphere. The pressure mode is an
application with the outlet port of the compressor core connected
to a process through the SPT while the inlet port of the compressor
core is interfaced directly to the IAS which in turn is open to
atmosphere. And the deep vacuum mode is the same as the vacuum mode
for the inlet and outlet port connections, but it has a 3rd jet
port open to atmosphere that allows cool atmospheric air into the
compressor cavity through the SPT to extend the pressure ratio
range (e.g., from about 2/1 for such two-port applications) up to
about 10/1. Additional IASs can be used for jet ports as
desired.
[0033] Another embodiment of the invention includes an integrated
vacuum and pressure (IVP) feature that provides for dual operation
in the vacuum mode or in the pressure mode. IVP embodiments are
well-suited for mobile applications where noise, space, and weight
are primary requirements. In typical IVP embodiments, the IRPDCs
with the SPTs and the IASs additionally include with an integrated
4-way valve for example located in front of the compressor core
inlet/outlet to switch the same system between the vacuum mode and
pressure mode. Some IVP embodiments, such as a liquid tank hauler
that uses vacuum to load and pressure to unload, can include two
4-way valves to operate in the pressure mode or the deep vacuum
mode. The second 4-way valve opens or closes a jet flow from
atmosphere to help reach deep vacuum or stays for normal
pressure/vacuum mode. The jet IAS is included in this case while a
discharge IAS and a discharge SPT are optional for IVP
embodiments.
[0034] Turning now to the drawings, FIGS. 4a-5e show various
integrated rotary positive-displacement compressors (IRPDCs) with
shunt pulsation traps (SPTs) and integrated absorptive silencers
(IASs) according to various example embodiments of the present
invention. Although specific embodiments of the invention are
described and illustrated, it should be understood that such
embodiments are examples only and merely illustrative of but a
small number of the many possible embodiments of the present
invention. For example, most of the drawings and description are
devoted to IRPDCs representing improvements in a Roots-type RPDC
for controlling gas pulsations and noises in an under-compression
mode, but the other types of RPDCs (including those identified in
FIG. 1) can be adapted to implement the same improvements. In
addition to compressors and vacuum pumps, rotary
positive-displacement expanders (a variation used to generate shaft
power from gas-media pressure drop) are included within the meaning
of RPDCs. Also, the invention can be implemented in various
embodiments for use with a range of gas media such as vapor-liquid
two-phase flow as used in air conditioning or refrigeration.
[0035] FIG. 4a shows a compression cycle of an innovative IRPDC
with an SPT combined with an IAS according to various example
embodiments of the invention. The SPT is connected in parallel with
a cavity/core of the compressor and used to trap and break up the
single, big, fast jet (IFF and EW) of the primary low-frequency
pulsation into multiple smaller and slower jets that generate
higher-frequency noises (see, e.g., FIG. 3b for a Roots
compressor). Additional details of conventional RPDCs with SPTs are
disclosed in for example U.S. Pat. Nos. 9,140,260; 9,151,292;
9,140,261; 9,243,557; 9,551,342; and 9,732,754, which have been
incorporated by reference, and thus such additional details are not
repeated herein for brevity and clarity.
[0036] The IRPDCs of the present invention additionally include an
IAS that is serially connected with the compressor cavity/core and
used to attenuate the secondary pulsations generated due to lobe
meshing and the higher-frequency noises induced from the SPT in
order to reduce the flow-borne pulsation and noises carried to
downstream equipment and/or to the atmosphere. This is in contrast
to conventional combination type pulsation dampening and noise
attenuation devices (see, e.g., FIG. 2e), which are connected in
series with the compressor discharge port (see, e.g., FIG. 2a), and
which do no indiscriminate between low-frequency pulsations and
high-frequency noises. The IRPDCs improve on this conventional
design by combining an IAS with an SPT to separate the main flow
(Q) from the primary pulsed flow (IFF) so that only the primary
pulsed flow (IFF) will go through the SPT dampener and be
attenuated there for the primary low-frequency large-amplitude
pulsations, while the secondary pulsations and high-frequency
noises are carried with the main flow (Q) to be treated by the
serially connected IAS (see FIG. 4a).
[0037] There are several unique features and advantages of the
IRPDCs with the parallel SPTs and the IASs of the present invention
compared with traditional serially connected single dampeners.
First of all, the primary pulsed flow (IFF) is separated out from
the main cavity flow (Q) through the parallel SPT dampener so that
an effective attenuation on the primary pulsed flow IFF will not
create any serial back-pressure for the compressor to overcome,
resulting in work saving (see FIG. 3c), hence enhancing both the
compressor system efficiency across the whole flow range and the
pulsation attenuation effectiveness with a much smaller-sized
reactive dampening device (typically, at least 10 times smaller in
volume). In a conventional serially connected reactive dampener
(see, e.g., FIGS. 2c and 2e), both pulsed flow IFF and main flow Q
travel through the dampening device where a better attenuation on
pulsed flow IFF comes at the cost of higher compressor back
pressure or larger dampener size to accommodate the combined Q and
IFF flow. A compromise is often made in order to reduce compressor
back pressure by sacrificing the degree of pulsation dampening or
by using a very large-volume dampener, resulting in a bulky, heavy,
and costly dampener.
[0038] Secondly, by first pre-treating the primary pulsations by
the SPT, the left-over secondary pulsations and induced
high-frequency noises can be effectively treated by an
absorptive-type silencer. This absorptive-type silencer has
much-lower back-pressure losses (typically, at least 10 times
lower) than the same-sized reactive-type silencer, hence less work
is needed (see FIG. 3c). And this absorptive-type silencer can be
of a much-smaller size than conventional pulsation-dampening
devices.
[0039] Thirdly, the SPT attenuates the primary pulsations much
closer to the pulsation source (the compressor core/cavity) than in
a conventional serial scheme and enables the use of a much-smaller
sized absorptive-type silencer (without creating any serial back
pressure), and at least in part because of this the absorptive
silencer can be included as an integral part of the casing. As
such, the IAS is a specialized and integrated design of a
conventional absorptive-type silencer. For example, the
absorptive-type silencer can be included as close as possible to
the compressor core/cavity, in a conforming shape with its flow
channels folded, so that the overall size and footprint of the
compressor package is much smaller relative to the prior art. Also,
by replacing the traditional flange-connected cylindrical-shaped
absorptive dampener (see, e.g., FIG. 2d) with a directly and
seamlessly interfaced specialized IAS to the compressor core (see,
e.g., FIG. 4b), the back-pressure loss and material consumption are
further reduced by eliminating the cross-sectional shape transition
from the compressor core's rectangular inlet/outlet (also called
the suction/discharge port) to the circular-flanged traditional
silencer. Moreover, noise is further reduced due to the added turns
in the folded flow passage that blocks the direct path of the sound
propagation from the compressor core and due to the elimination of
some of the noise radiation surfaces from the naked casing now
covered by the IAS. Other features and advantages are further
described throughout the specification and drawings.
[0040] Referring specifically to FIG. 4c1, there is shown an IRPDC
10 integrally combined with an SPT 30, a jet IAS 40, and a
discharge IAS 50 according to a first example embodiment of the
invention. Other embodiments of the IRPDC with the SPT include only
the jet IAS 40, only the discharge IAS 50, and/or additionally one
or more other IASs.
[0041] The IRPDC 10 of the depicted embodiment is a Roots-type
compressor, though other embodiments include other types of IRPDCs
(e.g., vacuum pumps and expanders) equipped with the SPT and the
IAS, as noted herein. The IRPDC 10 includes a compressor core 20
and two parallel-axis rotors 24, with the compressor core 20
including a casing 21 that defines a compression chamber 26 with an
integral suction port 22 and an integral discharge port 28, and
with the rotors 24 housed in the compression chamber 26 and
configured for propelling gas-flow from the suction port 22 to the
discharge port 28.
[0042] The SPT 30 is arranged adjacent to the compressor core 20
and includes a pulsation trap chamber 36, an injection port (trap
inlet) 32 branching off from the compression chamber 26 into the
pulsation trap chamber 36, a feedback port (trap outlet) 38
communicating with the compressor core outlet 28, and a pulsation
dampener 34 housed in the pulsation trap chamber 36 and interfaced
with the trap inlet 32. The pulsation dampener 34 can be of a
variety of different types, including an M-shaped dampener (as
depicted) or other conventional dampeners as have been incorporated
by reference. It should be pointed out that the pulsation trap
chamber 36 becomes an expansion chamber when the pulsation dampener
34 is absent.
[0043] The jet IAS 40 and the discharge IAS 50 are each integrated
into the IRPDC 10 and arranged adjacent to the compressor core 20,
with the jet IAS 40 positioned generally opposite the SPT 30. In
some embodiments such as that depicted, the jet IAS 40 and the
discharge IAS 50 cooperate with the SPT 30 to conform to the shape
of and generally surround (e.g., on three sides) the compressor
core 20.
[0044] The jet IAS 40 includes an outlet 42 interfacing with the
trap outlet 38 and a flow channel 44 leading to an inlet 48
communicating with the compressor core outlet 28. Typically, the
flow channel 44 is folded or non-linear, with two (or another
number of) turns, with each (or at least one) turn equal to or
greater than about 180 degrees. Also, the flow channel 44 is
defined by channel walls 47 made of for example conventional
perforated plates, with conventional absorptive dampening material
46 surrounding the channel 44 (e.g., sandwiched between the
perforated channel walls 47 and a casing of the IAS 40).
[0045] The discharge IAS 50 includes an inlet 52 interfacing with
the compressor core outlet 28 including at least one flow channel
54 leading to an outlet 58 for discharging the gas-flow (to
atmosphere in vacuum mode). In the depicted embodiment, the IAS 50
includes a flow divider (e.g., with a protruding lip) 53 for
splitting the gas-flow into two folded flow channels 54 that each
terminate at a flow merger 55 (e.g., arranged symmetrically with
the divider 53) before discharging to the outlet 58. Typically, the
flow channel 54 on each side is folded or non-linear, with three
(or another number of) turns, with two end turns each equal to or
greater than about 90 degrees, and with one middle turn equal to or
greater than about 180 degrees. The folded flow channels 54 are
defined by channel walls 57 made of for example conventional
perforated plates, with conventional absorptive dampening material
56 (see, e.g., FIG. 4c2) surrounding the channels 54 (e.g.,
sandwiched between the perforated walls 57 and a casing of the IAS
50).
[0046] In operation of the IRPDC 10, the rotors 24 propel a main
cavity flow (as indicated by the large directional arrows pointing
into and out of the compressor cavity) from the suction port 22 to
the discharge port 28 and into the discharge IAS 50, while a
feedback flow (IFF) 43 (as indicated by the small directional
arrows) goes from the compressor core outlet 28 through the jet IAS
40 into the trap outlet 38 into the pulsation trap dampener 34 and
converging into the injection port (trap inlet) 32 and releasing
into the compression chamber 26. As each rotor lobe tip passes over
the trap inlet 32 (see, e.g., the left rotor in FIG. 3b, which
shows the SPT wave and flow patterns in more detail and thus
illustrates the equivalent wave and flow pattern for FIG. 4c1), a
series of compression waves are generated at the trap inlet 32
going into the compression chamber 26, thereby inducing the
feedback flow (IFF) 43. Simultaneously, a series of expansion waves
are generated at the trap inlet 32, but travelling in a direction
opposite to the feedback flow 43, that is, from the trap inlet 32,
through the dampener 34 where it is trapped and the induced
single-jet IFF is broken into multiple smaller jets that generate
high-frequency noises, which radiate into the trap outlet 38. The
jet IAS 40 thus intercepts and attenuates the high-frequency noise
generated by the SPT 30 before it reaches the IRPDC outlet 28.
[0047] At the same time, the main cavity flow is propelled by the
rotors 24 from the suction port 22 to the discharge port 28,
generating secondary pulsations from the rotors (e.g., lobes) 24
meshing and inducing wide-band noises. The discharge IAS 50 is used
to tackle these secondary pulsations and noises plus what is left
from the jet IAS 40 by splitting the main flow into two oppositely
traveling branches/channels 54 where the sound absorbing surface
area can be maximized to turn flow vibration energy into heat
through the absorptive materials 56.
[0048] Referring to FIG. 4c3, a second example embodiment of the
invention includes a modified discharge IAS 51 that can be
integrated into the IRPDC with the SPT of any of the embodiments
disclosed herein. This discharge IAS 51 includes two flow
branches/channels that split and meet again, as in the first
embodiment, but with different flow channel lengths. For example,
the difference between the first flow channel length L1 and the
second flow channel length L2 can be about 1/4 wave length so that
the noise carried by the two flow channels can be cancelled out at
that frequency, further reducing noise.
[0049] When a rotary blower IRPDC 10 equipped with the SPT 30 is
combined with any of the IASs 40, 50, and 51 described herein,
there is provided a significant reduction in gas pulsation and
induced noise at the source and improved compressor design and
off-design efficiency without using a traditional serial pulsation
dampener and while being light in mass, compact in size, and
suitable for high-efficiency variable pressure-ratio
applications.
[0050] FIG. 4d shows an IRPDC 10 integrally combined with an SPT
30, a suction IAS 65, and an optional jet IAS 69 according to a
third example embodiment of the invention. Other embodiments of the
IRPDC with the SPT include only the suction IAS 65, only the
optional jet IAS 69, and/or additionally one or more other IASs.
The IRPDC 10 is shown operating in pressure mode with the outlet
port 28 of the compressor core 20 communicating with a process by
flange 68 while the inlet port 22 of the compressor core 20 is
interfaced directly to the suction IAS 65 which in turn is open to
atmosphere. The SPT 30 functions the same way as in the vacuum mode
described above and can still be optionally connected with the jet
IAS 69. Feedback flow 43 is also shown for clarity.
[0051] In addition, an inlet dampener 67 can be added between the
compressor core inlet 22 and the suction IAS outlet 66, for example
as depicted. The inlet dampener 67 is selected and configured to
dampen some of the secondary pulsations due to the rotor lobes 24
sudden un-meshing.
[0052] FIG. 4e shows an IRPDC 10 integrally combined with an SPT
30, at least one jet IAS 71, and a discharge IAS 50 according to a
fourth example embodiment of the invention. Other embodiments of
the IRPDC with the SPT include only the discharge IAS 50, only the
jet IAS 71, and/or additionally one or more other IASs. The IRPDC
10 is shown operating in deep vacuum mode and has the same inlet 22
and outlet 28 port connections as the vacuum mode. However, the jet
IAS 71 has an inlet 72 that is open to atmosphere that allows cool
atmospheric air flow in (as shown by the small directional arrows)
through the SPT 30 into the compression chamber 26 of the
compressor core 20 to extend the pressure ratio range (e.g., from
about 2/1 as typical for the above defined 2-port applications to
about 10/1 in this mode). The jet IAS 71 is separated from the
discharge port 28 and directly communicates with cool atmospheric
air at the inlet 72 without going through the discharge IAS 50 as
in vacuum mode.
[0053] Additional embodiments of the invention provide integrated
vacuum and pressure operation, with this sometimes referred to
herein as IVP technology. IVP is ideal for mobile applications
(e.g., liquid tank haulers) and other applications where noise,
space and weight are primary requirements.
[0054] FIGS. 5a-5c show an IRPDC 10 integrally combined with an SPT
30, a discharge IAS 50, and a 4-way flow-direction valve 81
according to a fifth example embodiment of the invention. Other
embodiments of the IRPDC with the SPT include 4-way-valve 75 with
other configurations of IASs. This embodiment combines the vacuum
mode with the pressure mode as one dual-purpose (pressure and
vacuum) machine with the integrated 4-way valve 81 for switching
between the vacuum mode (FIG. 5b) and the pressure mode (FIG.
5c).
[0055] FIG. 5b shows the 4-way valve 81 located in front of the
compressor core 20 and set for vacuum mode when port 83 connecting
to a system is connected with the compressor core inlet 22, while
port 82 connecting to atmosphere is connected with the compressor
core outlet 28. On the other hand, FIG. 5c shows the 4-way valve 81
valve position for pressure mode, but the same port 83 is now
connecting with the compressor core outlet 28 through the SPT 30,
while the same port 82 is now acting as the inlet port connecting
with the compressor core inlet 22. It should be noted that the
flows in and out of the compressor core 20 always stay the same
under vacuum and pressure mode, and so do the feedback flows 43
(indicated by the small directional arrows) that go from the
compressor core outlet 28 through part of the discharge IAS 50
(suction IAS is optional, not shown here) into the SPT 30 and into
the compression chamber 26. During vacuum mode (FIG. 5b), the inlet
flow from the connected system is sucked through port 83 as
directed by 4-way valve 81 towards the compressor core inlet 22
(indicated by the large directional arrows) while the main
discharge flow travels through the discharge IAS 50 and is guided
by the 4-way valve 81 to discharge at port 82.
[0056] FIGS. 5d and 5e show an IRPDC 10 integrally combined with an
SPT 30, a jet IAS 40, a discharge IAS 50, a 4-way flow-direction
valve 81, and a 4-way jet valve 91 according to a sixth example
embodiment of the invention. This embodiment is similar to that of
the fifth embodiment, for example it include the same IVP
technology, and additionally includes the jet valve 91 located at
the jet port 92 in FIG. 5d is set for deep vacuum mode when port 92
is connecting the cavity 26 of the compressor core 20 with
atmosphere except with the SPT 30 and the jet IAS 40 in-between.
This embodiment can be particularly suitable for use in mobile
applications such as liquid tank haulers that use vacuum to load
and pressure to unload.
[0057] During the deep vacuum mode shown in FIG. 5d, the inlet flow
from the connected system is sucked through port 83, as directed by
4-way flow-direction valve 81, towards the compressor core inlet 22
(as shown by the large arrows) while the main discharge flow
travels form the core outlet 28 through the discharge IAS 50 and is
guided by the 4-way valve 81 to discharge at port 82. However, the
feedback flow 43 (as indicated by the small arrows) goes from the
4-way jet valve 91, which is open to atmosphere now, through the
jet IAS 40 into the SPT 30 and into the compression chamber 26 for
additional cooling to reach deep vacuum.
[0058] When the 4-way jet valve 91 is set closed to atmosphere, as
shown in FIG. 5e, the compressor is back to the pressure and vacuum
mode (as described above with respect to FIGS. 5b-5c). The two
4-way valves 81 and 91 are designed so that when the 4-way jet
valve 91 is open to atmosphere, the 4-way flow-direction valve 81
is in vacuum mode, and when the 4-way jet valve 91 is closed to
atmosphere, the 4-way flow-direction valve 81 is in pressure mode.
An interlocking and linkage mechanism can be provided for this
functionality.
[0059] In these and other embodiments of the invention, a single
casing/housing can be formed for the IRPDC including the SPT and
the IAS, for example by casting two cross-sectional halves each
including halve of the IRPDC, the SPT, and the IAS. Also, the IAS
flow channels can be generally rectangular and configured (e.g.,
sized and shaped) to conform to the outlet of the compressor core.
Further, the folds or turns in the IAS flow channels can have a
serpentine configuration with at least one 180-degree bend so that
the channel is folded back over itself.
[0060] Accordingly, various embodiments of the present invention
provide various advantages over the prior art. For example, an
IRPDC with an SPT and an IAS can provide for trapping and
attenuating not only primary pulsations but also the secondary
induced noises as well at the source. Also, an IRPDC with an SPT
and an IAS can provide for improving compressor system efficiency
by eliminating the back pressure loss resulted from the serially
connected traditional dampener at inlet or discharge. In addition,
an IRPDC with an SPT and an IAS can provide for a lighter weight
and more-compact size by eliminating the serially connected
traditional dampener at inlet or discharge. Furthermore, an IRPDC
with an SPT and an IAS for trapping and attenuating not only
primary pulsations but the secondary induced noises as well at
source, in a wide range of pressure ratios and/or in a wide range
of speeds and cavity passing frequency, without using a traditional
serial dampener.
[0061] It is to be understood that this invention is not limited to
the specific devices, methods, conditions, or parameters of the
example embodiments described and/or shown herein, and that the
terminology used herein is for the purpose of describing particular
embodiments by way of example only. Thus, the terminology is
intended to be broadly construed and is not intended to be
unnecessarily limiting of the claimed invention. For example, as
used in the specification including the appended claims, the
singular forms "a," "an," and "the" include the plural, the term
"or" means "and/or," and reference to a particular numerical value
includes at least that particular value, unless the context clearly
dictates otherwise. In addition, any methods described herein are
not intended to be limited to the sequence of steps described but
can be carried out in other sequences, unless expressly stated
otherwise herein.
[0062] While the claimed invention has been shown and described in
example forms, it will be apparent to those skilled in the art that
many modifications, additions, and deletions can be made therein
without departing from the spirit and scope of the invention as
defined by the following claims.
* * * * *