US2019195522A1PendingUtilityA1
Variable aperture orifice plate assembly
Est. expiryJul 12, 2033(~7 yrs left)· nominal 20-yr term from priority
F24F 2140/40G05B 2219/40573G05B 2219/2614G05B 17/02F24F 11/62F24F 11/56F24F 2110/40F24F 11/63F24F 2110/30F24F 11/79G05D 7/0635G05D 7/0676G05B 2219/36249F24F 11/64F24F 11/30F24F 11/58F24F 11/75
67
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Claims
Abstract
A variable aperture orifice plate assembly for controlling and/or measuring fluid flow therethrough, from an upstream end to a downstream end. The orifice plate assembly includes a damper assembly having an array of adjustable cross-section apertures having an aggregate aperture area, upstream and downstream pressure sensors on opposite sides of the damper assembly, an actuator assembly for adjustably controlling the aggregate area of the apertures, and a processor configured for feedback operation in a closed-loop, to effect operation as an orifice plate. The processor is responsive to differential pressure across the damper assembly, and the aggregate area of the respective apertures normal to the flow paths of fluid flowing therethrough, to control the differential pressure and/or the aggregate area in a closed-loop manner so that fluid flowing between the array of apertures and the downstream end, is characterized by a corresponding array of vena contractae.
Claims
exact text as granted — not AI-modified1 . An orifice plate system adapted for fluid flow therethrough in a flow region extending along a flow axis and laterally bounded by a tubular inward facing surface from an upstream end to a downstream end of the flow region, comprising:
A. a damper assembly adapted for disposition in the flow region along the fluid flow axis having a first side facing the upstream end and a second side opposite the first side and facing the downstream end, and defining an array of one or more adjustable cross-section area variable apertures characterized by an aggregate area A o within the bounds of the inward facing surface and defining fluid flow paths therethrough between an upstream portion of the flow region between the first side and the upstream end and a downstream portion of the fluid region between the second side and the downstream end, wherein A o is representative an aggregate of areas of cross-sections of the apertures of the array of apertures normal to fluid flow paths passing through the apertures, B. an upstream sensor adapted for sensing upstream pressure at an upstream pressure sense locus in an upstream portion of the flow region displaced distal in the direction of the flow axis from the first side, C. a downstream sensor adapted for sensing downstream pressure in at least one downstream pressure sense locus in a downstream portion of the flow region proximal in the direction of the flow axis to the second side and between perimeters of apertures of the array of apertures in a downstream portion of the flow region. D. an actuator assembly adapted to adjust the cross-section areas of respective variable apertures of the array in response to an applied damper area control signal, and E. a processor responsive to:
i. the sensed upstream pressure and sensed downstream pressure to generate a pressure difference signal representative of a differential pressure ΔP along the flow axis across the damper assembly,
ii. the actuator assembly to generate an aperture signal representative of the area of the respective apertures normal to flow paths of fluid flowing therethrough,
iii. the pressure difference signal, and the aperture signal to generate a damper area control signal, and apply the damper area control signal to the actuator assembly, in a closed loop manner,
whereby fluid flows from the upstream end, through the array of apertures characterized by aggregate area A o normal to the flow therethrough, and to the downstream end wherein the fluid flowing between the array of apertures and the downstream end, is characterized by a corresponding array of vena contractae having an aggregate cross section area A c normal to the fluid flow therethrough, where A c <A c , and A c is less than the aggregate cross section area normal to fluid flow elsewhere between the array of apertures and the downstream end,
thereby establishing a contraction coefficient C, wherein
C
=
A
c
A
o
whereby the processor is responsive to contraction coefficient C, the aperture signal and the pressure signal, to regulate the variable apertures over time in a closed loop manner so that a set point is attained.
2 . An orifice plate system according to claim 1 wherein
the upstream pressure sense locus is disposed upstream of portions of the flow region between the upstream pressure locus and the first side of the damper assembly in which fluid flow is disturbed by the damper assembly.
3 . An orifice plate assembly according to claim 1 , wherein:
i. the sensed upstream pressure is a total pressure TP upstream at the upstream pressure sense locus, and ii. the sensed downstream stream pressure is a static pressure SP downstream at the at least one downstream pressure sense locus.
4 . An orifice plate assembly according to claim 3 wherein ΔP=TP upstream −SP downstream .
5 . An orifice plate system according to claim 4 wherein C is a flow coefficient C F corresponding to:
C
F
=
A
c
A
o
=
c
1
-
(
1
-
c
)
(
A
o
A
d
)
2
wherein
i. A d is representative of the cross-section area of the flow region normal to the flow axis and adjacent to the damper assembly within the bounds of the inward facing surface, and
ii. c is representative of, for an inviscid fluid flowing through a relatively small aperture in a relatively large plate in response to a pressure differential across the plate, a ratio of an area normal to a vena contracta of fluid flowing through the aperture, to an area of the aperture normal to fluid flow through the aperture.
6 . An orifice plate assembly according to claim 5 further comprising a flow rate processor adapted to determine the flow rate Q of the fluid flowing through the downstream region, wherein
Q
=
(
A
c
A
o
)
A
o
2
Δ
P
ρ
=
C
F
A
o
2
Δ
P
ρ
where
i. ρ is representative of the density of the fluid, and
ii. ΔP is representative of the differential pressure along the flow axis across the damper assembly.
7 . An orifice plate assembly according to claim 3 wherein the at least two of the downstream pressure sense loci are contiguous.
8 . An orifice plate assembly according to claim 1 , wherein:
i. the sensed upstream pressure is a static pressure SP upstream at the upstream pressure sense locus, and ii. the sensed downstream stream pressure is a static pressure SP downstream at the at least one downstream pressure sense locus.
9 . An orifice plate assembly according to claim 8 wherein ΔP=SP upstream −SP downstream .
10 . An orifice plate system according to claim 9 wherein C is a discharge coefficient C d corresponding to:
C
d
=
c
[
1
-
(
1
-
c
)
2
(
A
o
A
d
)
2
]
wherein
i. A d is representative of the cross-section area of the flow region normal to the flow axis and adjacent to the damper assembly within the bounds of the inward facing surface, and
ii. c is representative of, for an inviscid fluid flowing through a relatively small aperture in a relatively large plate in response to a pressure differential across the plate, a ratio of an area normal to a vena contracta of fluid flowing through the aperture, to an area of the aperture normal to fluid flow through the aperture.
11 . An orifice plate assembly according to claim 10 further comprising a flow rate processor adapted to determine the flow rate Q of fluid flowing through the downstream region, wherein
Q
=
C
d
A
o
[
1
-
(
A
o
A
d
)
2
]
2
Δ
P
ρ
where
i. ρ is representative of the density of the fluid, and
ii. ΔP is representative of the differential pressure along the flow axis across the damper assembly.
12 . An orifice plate assembly according to claim 8 wherein the at least two of the downstream pressure sense loci are contiguous.
13 . An orifice plate assembly according to claim 1 wherein the tubular inward facing surface adjacent to the damper assembly in a region along the flow axis adjacent to the damper assembly has an inward facing surface shape, and the damper assembly is a butterfly damper having area A damper which is pivotable about an axis traversing the flow region and normal to the flow axis and having a periphery matching the inward facing surface in shape, and
wherein:
A o =A duct −A damper cos θ damper
where:
i. A o is representative of the area of an aperture between the periphery of the butterfly damper and the inward facing surface normal to fluid flowing therethrough,
ii. A duct is representative of the cross-section area of the flow region adjacent to the damper assembly within the bounds of the inward facing surface,
iii. A damper is representative of the cross-section area of the butterfly damper, and
iv. θ damper is representative of the angle of the butterfly damper relative to an angle at θ damper =0 when the butterfly damper fully spans the flow region thereby blocking fluid flow from the upstream portion of the flow region to the downstream portion of the flow region.
14 . An orifice plate assembly according to claim 13 , wherein the tubular inward facing surface adjacent to the damper assembly has a circular cross section having radius R in a region adjacent to a periphery of the butterfly damper when θ damper =0, and
wherein the butterfly damper is a circular butterfly damper having radius R, and the inward facing surface defines a circle having a matching shape at points along the flow axis adjacent to the periphery of the butterfly damper when θ damper =0.
15 . An orifice plate assembly according to claim 13 , wherein the tubular inward facing surface adjacent to the damper assembly has an elliptical cross section having in a region adjacent to a periphery of the butterfly damper when θ damper =0, and
wherein the butterfly damper is an elliptical butterfly damper having an elliptical periphery, and the inward facing surface defines an ellipse having a matching shape at points along the flow axis adjacent to the periphery of the damper when θ damper =0.
16 . An orifice plate assembly according to claim 13 , wherein the tubular inward facing surface adjacent to the damper assembly has a rectangular cross section in a region adjacent to a periphery of the butterfly damper when θ damper =0, and
wherein the butterfly damper is a rectangular butterfly damper having a rectangular periphery, and the inward facing surface defines a rectangle having a matching shape at points along the flow axis adjacent to the periphery of the damper when θ damper =0.
17 . An orifice plate assembly according to claim 1 wherein the tubular inward facing surface adjacent to the damper assembly in a region along the flow axis adjacent to the damper assembly has an inward facing surface shape, and wherein the damper assembly includes an annulus damper disposed about an inner disk damper, wherein the annulus damper has area A annulus disposed about a central aperture characterized by an aperture shape, and is pivotable about an axis traversing the flow region, and has a periphery matching the inward facing surface in shape in a region along the flow axis adjacent to the damper assembly, wherein the inner disk damper has area A disk and is pivotable with respect to the annulus damper about an axis traversing the annulus aperture, and has a periphery matching the periphery of the annulus central aperture in shape, and wherein
A o =A disk sin θ disk +( A duct −A disk )( I −cos θ annulus )
where:
i. A o is representative of the aggregate area of an aperture between the periphery of the annulus damper and the inward facing surface normal to fluid flowing therethrough, and the area of an aperture between the periphery of the disk damper and the annulus damper normal to fluid flowing therethrough,
ii. A duct is representative of the cross-section area of the flow region adjacent to the damper assembly within the bounds of the inward facing surface normal to fluid flowing therethrough,
iii. θ annulus is representative of the angle of the annulus damper relative to an angle at θ annulus =0 when the annulus damper is in a closed position fully spanning the flow region thereby blocking fluid flow past a periphery thereof from the upstream portion of the flow region to the downstream portion of the flow region, and
iv. θ disk is representative of an angle of the disk damper relative to an angle at θ disks =0 when the disk damper is angularly aligned with the annulus damper in the closed position.
18 . An orifice plate assembly according to claim 17 , wherein the tubular inward facing surface adjacent to the damper assembly has a circular cross section having radius R in a region adjacent to a periphery of the butterfly damper when θ damper =0
19 . An orifice plate assembly according to claim 17 , wherein the tubular inward facing surface adjacent to the damper assembly has an elliptical cross section in a region adjacent to a periphery of the butterfly damper when θ damper =0.
20 . An orifice plate assembly according to claim 17 , wherein the tubular inward facing surface adjacent to the damper assembly has a rectangular cross section having radius R in a region adjacent to a periphery of the butterfly damper when θ damper =0.
21 . An orifice plate assembly according to claim 5 wherein c is a value in a range 0.536-0.753.
22 . An orifice plate assembly according to claim 5 wherein c=0.61.
23 . An orifice plate assembly according to claim 5 wherein c=0.611.
24 . An orifice plate assembly according to claim 5 wherein c=0.62.
25 . An orifice plate assembly according to claim 10 wherein c is a value in a range 0.536-0.753.
26 . An orifice plate assembly according to claim 10 wherein c=0.61.
27 . An orifice plate assembly according to claim 10 wherein c=0.611.
28 . An orifice plate assembly according to claim 10 wherein c=0.62.
29 . An orifice plate assembly according to claim 1 wherein the set point is a temperature of a region to be controlled which is pneumatically coupled to and downstream from the damper assembly.
30 . An orifice plate assembly according to claim 1 wherein the set point is a flow rate for fluid flowing from the upstream portion of the flow region to the downstream portion of the flow region.
31 . An orifice plate assembly according to claim 30 wherein the set point is in a flow rate range from a relatively high rate fluid velocity R high to relatively low rate fluid velocity R low wherein the flow rate range extends below and above an intermediate fluid velocity value, and wherein at an equilibrium, the flow rate is within a predetermined percentage of the set point in a predetermined percentage range about the set point over the flow rate range.
32 . An orifice plate assembly according to claim 31 wherein the intermediate fluid velocity value is 300 FPM.
33 . An orifice plate assembly according to claim 31 wherein a ratio of flow rate range limits R high :R low defines a turndown ratio range greater than 3:1.
34 . An orifice plate assembly according to claim 33 wherein the predetermined percentage is in a percentage range 3-30% over the flow rate range.
35 . An orifice plate assembly according to claim 34 wherein the intermediate value is 300 FPM, R high is 3000 FPM and R low is 1 FPM.
36 . An orifice plate assembly according to claim 31 wherein a ratio of flow rate range limits R high :R low defines a turndown ratio range 3000:1 to 3:1.
37 . An orifice plate assembly according to claim 36 wherein the predetermined percentage is a value in a percentage range 3-30% over the flow rate range.
38 . An orifice plate assembly according to claim 37 wherein the intermediate value is 300 FPM, R high is 3000 FPM and R low is 1 FPM.
39 . An orifice plate assembly according to claim 37 wherein the predetermined percentage is a value in the percentage range which is a function of flow rate over the flow rate range.
40 . An orifice plate assembly according to claim 37 wherein, in operation at a fixed flow rate in the turndown range where the turndown ratio range is 300:1 to 3:1, the predetermined percentage is a fixed value over the flow rate range.
41 . An orifice plate assembly according to claim 31 wherein the predetermined percentage is less than or equal to 5%.
42 . An orifice plate system adapted for fluid flow therethrough in a flow region extending along a flow axis and laterally bounded by a tubular inward facing surface from an upstream end to a downstream end of the flow region, comprising:
A. a damper assembly adapted for disposition in the flow region along the fluid flow axis having a first side facing the upstream end and a second side opposite the first side and facing the downstream end, and defining an array of one or more adjustable cross-section area variable apertures characterized by an aggregate area A o within the bounds of the inward facing surface and defining fluid flow paths therethrough between an upstream portion of the flow region between the first side and the upstream end and a downstream portion of the fluid region between the second side and the downstream end, wherein A o is representative an aggregate of areas of cross-sections of the apertures of the array of apertures normal to fluid flow paths passing through the apertures, B. an upstream sensor adapted for sensing upstream pressure at an upstream pressure sense locus in an upstream portion of the flow region displaced distal in the direction of the flow axis from the first side, C. a downstream sensor adapted for sensing downstream pressure in at least one downstream pressure sense locus in a downstream portion of the flow region proximal in the direction of the flow axis to the second side and between perimeters of apertures of the array of apertures in a downstream portion of the flow region. D. a net pressure source assembly adapted to effect an adjustable net fluid pressure across an upstream point at or upstream of the upstream pressure sense locus and a downstream point at or downstream of the downstream pressure sense locus, in response to an applied net pressure control signal, E. an actuator assembly adapted to adjust the cross-section areas of respective variable apertures of the array in response to an applied damper area control signal, and F. a processor responsive to:
i. the sensed upstream pressure and sensed downstream pressure to generate a pressure difference signal representative of a differential pressure ΔP along the flow axis across the damper assembly,
ii. the net pressure source assembly to generate a net pressure control signal representative of a differential pressure across the upstream point and the downstream point,
iii. the actuator assembly to generate an aperture signal representative of the area of the respective apertures normal to flow paths of fluid flowing therethrough,
iv. the pressure difference signal, and the aperture signal to generate a damper area control signal, and apply the damper area control signal to the actuator assembly, and apply the net pressure control signal to the net pressure source assembly, all in a closed loop manner,
whereby fluid flows from the upstream end, through the array of apertures characterized by aggregate area A o normal to the flow therethrough, and to the downstream end wherein the fluid flowing between the array of apertures and the downstream end, is characterized by a corresponding array of vena contractae having an aggregate cross section area A o normal to the fluid flow therethrough, where A c <A o , and A o is less than the aggregate cross section area normal to fluid flow elsewhere between the array of apertures and the downstream end,
thereby establishing a contraction coefficient C, wherein
C
=
A
c
A
o
whereby the processor is responsive to contraction coefficient C, the aperture signal and the pressure signal, to regulate the variable apertures over time in a closed loop manner so that a set point is attained.
43 . An orifice plate system according to claim 42 wherein
the upstream pressure sense locus is disposed upstream of portions of the flow region between the upstream pressure locus and the first side of the damper assembly in which fluid flow is disturbed by the damper assembly.
44 . An orifice plate assembly according to claim 42 , wherein:
i. the sensed upstream pressure is a total pressure TP upstream upstream at the upstream pressure sense locus, and ii. the sensed downstream stream pressure is a static pressure SP downstream at the at least one downstream pressure sense locus.
45 . An orifice plate assembly according to claim 44 wherein ΔP=TP upstream −SP downstream .
46 . An orifice plate system according to claim 45 wherein C is a flow coefficient C F corresponding to:
C
F
=
A
c
A
o
=
c
1
-
(
1
-
c
)
(
A
o
A
d
)
2
wherein
i. A d is representative of the cross-section area of the flow region normal to the flow axis and adjacent to the damper assembly within the bounds of the inward facing surface, and
ii. c is representative of, for an inviscid fluid flowing through a relatively small aperture in a relatively large plate in response to a pressure differential across the plate, a ratio of an area normal to a vena contracta of fluid flowing through the aperture, to an area of the aperture normal to fluid flow through the aperture.
47 . An orifice plate assembly according to claim 46 further comprising a flow rate processor adapted to determine the flow rate Q of the fluid flowing through the downstream region, wherein
Q
=
(
A
c
A
o
)
A
o
2
Δ
P
ρ
=
C
F
A
o
2
Δ
P
ρ
where
i. ρ is representative of the density of the fluid, and
ii. ΔP is representative of the differential pressure along the flow axis across the damper assembly.
48 . An orifice plate assembly according to claim 44 wherein the at least two of the downstream pressure sense loci are contiguous.
49 . An orifice plate assembly according to claim 42 , wherein:
i. the sensed upstream pressure is a static pressure SP upstream at the upstream pressure sense locus, and ii. the sensed downstream stream pressure is a static pressure SP downstream at the at least one downstream pressure sense locus.
50 . An orifice plate assembly according to claim 49 wherein ΔP=SP upstream −SP downstream .
51 . An orifice plate system according to claim 50 wherein C is a discharge coefficient C d corresponding to:
C
d
=
c
[
1
-
(
1
-
c
)
2
(
A
o
A
d
)
2
]
wherein
i. A d is representative of the cross-section area of the flow region normal to the flow axis and adjacent to the damper assembly within the bounds of the inward facing surface, and
ii. c is representative of, for an inviscid fluid flowing through a relatively small aperture in a relatively large plate in response to a pressure differential across the plate, a ratio of an area normal to a vena contracta of fluid flowing through the aperture, to an area of the aperture normal to fluid flow through the aperture.
52 . An orifice plate assembly according to claim 51 further comprising a flow rate processor adapted to determine the flow rate Q of fluid flowing through the downstream region, wherein
Q
=
C
d
A
o
[
1
-
(
A
o
A
d
)
2
]
2
Δ
P
ρ
where
i. ρ is representative of the density of the fluid, and
ii. ΔP is representative of the differential pressure along the flow axis across the damper assembly.
53 . An orifice plate assembly according to claim 49 wherein the at least two of the downstream pressure sense loci are contiguous.
54 . An orifice plate assembly according to claim 42 wherein the tubular inward facing surface adjacent to the damper assembly in a region along the flow axis adjacent to the damper assembly has an inward facing surface shape, and the damper assembly is a butterfly damper having area A damper which is pivotable about an axis traversing the flow region and normal to the flow axis and having a periphery matching the inward facing surface in shape, and
wherein:
A o =A duct −A damper cos θ damper
where:
i. A o is representative of the area of an aperture between the periphery of the butterfly damper and the inward facing surface normal to fluid flowing therethrough,
ii. A duct is representative of the cross-section area of the flow region adjacent to the damper assembly within the bounds of the inward facing surface,
iii. A damper is representative of the cross-section area of the butterfly damper, and
iv. θ damper is representative of the angle of the butterfly damper relative to an angle at θ damper =0 when the butterfly damper fully spans the flow region thereby blocking fluid flow from the upstream portion of the flow region to the downstream portion of the flow region.
55 . An orifice plate assembly according to claim 54 , wherein the tubular inward facing surface adjacent to the damper assembly has a circular cross section having radius R in a region adjacent to a periphery of the butterfly damper when θ damper =0, and
wherein the butterfly damper is a circular butterfly damper having radius R, and the inward facing surface defines a circle having a matching shape at points along the flow axis adjacent to the periphery of the butterfly damper when θ damper =0.
56 . An orifice plate assembly according to claim 54 , wherein the tubular inward facing surface adjacent to the damper assembly has an elliptical cross section having in a region adjacent to a periphery of the butterfly damper when θ damper =0, and
wherein the butterfly damper is an elliptical butterfly damper having an elliptical periphery, and the inward facing surface defines an ellipse having a matching shape at points along the flow axis adjacent to the periphery of the damper when θ damper =0.
57 . An orifice plate assembly according to claim 54 , wherein the tubular inward facing surface adjacent to the damper assembly has a rectangular cross section in a region adjacent to a periphery of the butterfly damper when θ damper =0, and
wherein the butterfly damper is a rectangular butterfly damper having a rectangular periphery, and the inward facing surface defines a rectangle having a matching shape at points along the flow axis adjacent to the periphery of the damper when θ damper =0.
58 . An orifice plate assembly according to claim 42 ,
wherein the tubular inward facing surface adjacent to the damper assembly in a region along the flow axis adjacent to the damper assembly has an inward facing surface shape, and wherein the damper assembly includes an annulus damper disposed about an inner disk damper, wherein the annulus damper has area A annulus disposed about a central aperture characterized by an aperture shape, and is pivotable about an axis traversing the flow region, and has a periphery matching the inward facing surface in shape in a region along the flow axis adjacent to the damper assembly, wherein the inner disk damper has area A disk and is pivotable with respect to the annulus damper about an axis traversing the annulus aperture, and has a periphery matching the periphery of the annulus central aperture in shape, and wherein
A o =A disk sin θ disk +( A duct −A disk )(1−cos θ annulus )
where:
i. A o is representative of the aggregate area of an aperture between the periphery of the annulus damper and the inward facing surface normal to fluid flowing therethrough, and the area of an aperture between the periphery of the disk damper and the annulus damper normal to fluid flowing therethrough,
ii. A duct is representative of the cross-section area of the flow region adjacent to the damper assembly within the bounds of the inward facing surface normal to fluid flowing therethrough,
iii. θ annulus is representative of the angle of the annulus damper relative to an angle at θ annulus =0 when the annulus damper is in a closed position fully spanning the flow region thereby blocking fluid flow past a periphery thereof from the upstream portion of the flow region to the downstream portion of the flow region, and
iv. θ disk is representative of an angle of the disk damper relative to an angle at θ disks =0 when the disk damper is angularly aligned with the annulus damper in the closed position.
59 . An orifice plate assembly according to claim 58 , wherein the tubular inward facing surface adjacent to the damper assembly has a circular cross section having radius R in a region adjacent to a periphery of the butterfly damper when θ damper =0
60 . An orifice plate assembly according to claim 58 , wherein the tubular inward facing surface adjacent to the damper assembly has an elliptical cross section in a region adjacent to a periphery of the butterfly damper when θ damper =0.
61 . An orifice plate assembly according to claim 58 , wherein the tubular inward facing surface adjacent to the damper assembly has a rectangular cross section having radius R in a region adjacent to a periphery of the butterfly damper when θ damper =0.
62 . An orifice plate assembly according to claim 46 wherein c is a value in a range 0.536-0.753.
63 . An orifice plate assembly according to claim 46 wherein c=0.61.
64 . An orifice plate assembly according to claim 46 wherein c=0.611.
65 . An orifice plate assembly according to claim 46 wherein c=0.62.
66 . An orifice plate assembly according to claim 51 wherein c is a value in a range 0.536-0.753.
67 . An orifice plate assembly according to claim 51 wherein c=0.61.
68 . An orifice plate assembly according to claim 51 wherein c=0.611.
69 . An orifice plate assembly according to claim 51 wherein c=0.62.
70 . An orifice plate assembly according to claim 42 wherein the set point is a temperature of a region to be controlled which is pneumatically coupled to and downstream from the damper assembly.
71 . An orifice plate assembly according to claim 42 wherein the set point is a flow rate for fluid flowing from the upstream portion of the flow region to the downstream portion of the flow region.
72 . An orifice plate assembly according to claim 71 wherein the set point is in a flow rate range from a relatively high rate fluid velocity R high to relatively low rate fluid velocity R low wherein the flow rate range extends below and above an intermediate fluid velocity value, and wherein at an equilibrium, the flow rate is within a predetermined percentage of the set point in a predetermined percentage range about the set point over the flow rate range.
73 . An orifice plate assembly according to claim 72 wherein the intermediate fluid velocity value is 300 FPM.
74 . An orifice plate assembly according to claim 72 wherein a ratio of flow rate range limits R high :R low defines a turndown ratio range at least greater than 3:1.
75 . An orifice plate assembly according to claim 74 wherein the predetermined percentage is in a percentage range 3-30% over the flow rate range.
76 . An orifice plate assembly according to claim 75 wherein the intermediate value is 300 FPM, R high is 3000 FPM and R low is 1 FPM.
77 . An orifice plate assembly according to claim 72 wherein a ratio of flow rate range limits R high :R low defines a turndown ratio range 3000:1 to 3:1.
78 . An orifice plate assembly according to claim 77 wherein the predetermined percentage is a value in a percentage range 3-30% over the flow rate range.
79 . An orifice plate assembly according to claim 78 wherein the intermediate value is 300 FPM, R high is 3000 FPM and R low is 1 FPM.
80 . An orifice plate assembly according to claim 78 wherein the predetermined percentage is a value in the percentage range which is a function of flow rate over the flow rate range.
81 . An orifice plate assembly according to claim 78 wherein, in operation at a fixed flow rate in the turndown range where the turndown ratio range is 300:1 and 3:1, the predetermined percentage is a fixed value over the flow rate range.
82 . An orifice plate assembly according to claim 72 wherein the predetermined percentage is less than or equal to 5%.
83 . An orifice plate system according to claim 42 wherein the net pressure source assembly includes an upstream pressure source disposed upstream of the upstream pressure sense locus, wherein the upstream pressure source is adapted to effect variable pressure ΔP across the damper assembly in response to the applied net pressure control signal.
84 . An orifice plate system according to claim 42 wherein the net pressure source assembly includes a downstream pressure source disposed downstream of the downstream pressure sense locus, wherein the downstream pressure source is adapted to effect variable pressure ΔP across the damper assembly in response to the applied net pressure control signal.
85 . An orifice plate system according to claim 42 wherein the net pressure source assembly includes an upstream pressure source disposed upstream of the upstream pressure sense locus, and a downstream pressure source disposed downstream of the downstream pressure sense locus, wherein the upstream pressure source and the downstream pressure source are adapted to act in concert to effect variable pressure ΔP across the damper assembly in response to the applied net pressure control signal.
86 . An orifice plate assembly disposed within an inward-facing tubular wall extending along a flow axis from an upstream end to a downstream end, comprising:
A. a damper assembly traversing the inward-facing tubular wall and including downstream-facing surfaces defining an array of one or more adjustable cross section apertures defining a corresponding array of fluid flow paths therethrough,
wherein the array of apertures is characterized by an aggregate area A o corresponding to an aggregate of the aperture areas normal to the respective flow paths,
B. at least one upstream pressure sensor adapted to determine total pressure at at least one upstream pressure sense locus upstream of the damper assembly wherein the upstream pressure sense locus is between and spaced apart from the array of apertures and the upstream end, C. at least one downstream pressure sensor adapted to determine static pressure at at least downstream pressure sense locus downstream of the damper assembly wherein the at least one downstream pressure sense loci are pneumatically coupled and extend from the downstream-facing surfaces defining the array of apertures and toward the downstream end, D. an actuator assembly adapted for adjustably controlling the aggregate area A o , and E. a processor configured for feedback operation of the assembly in a closed-loop, to effect operation as an orifice plate,
wherein processor is responsive to:
i. the at least one upstream pressure sensor and the at least one downstream pressure sensor to determine differential pressure across the damper assembly, and
ii. the actuator assembly to determine the aggregate area A o of the respective apertures normal to the flow paths of fluid flowing therethrough, to control one or both of the differential pressure and the aggregate area A o in a closed-loop manner so that fluid flowing between the array of apertures and the downstream end, is characterized by a corresponding array of vena contractae.
87 . An orifice plate assembly according to claim 86 , wherein the array of vena contractae have an aggregate cross section area A c normal to the fluid flow therethrough, where A c <A o , and A c is less than the aggregate cross section area normal to fluid flow elsewhere between the array of apertures and the downstream end,
thereby establishing a contraction coefficient C, wherein C=A c /A n whereby the processor is responsive to contraction coefficient C, the aperture signal and the pressure signal, to regulate the variable apertures over time in a closed loop manner so that a set point is attained.
88 . An orifice plate assembly according to claim 87 , wherein:
i. the sensed upstream pressure is a total pressure TP upstream at the upstream pressure sense locus, and ii. the sensed downstream stream pressure is a static pressure SP downstream at the at least one downstream pressure sense locus.
89 . An orifice plate assembly according to claim 88 wherein ΔP=TP upstream −SP downstream .
90 . An orifice plate system according to claim 89 wherein C is a flow coefficient C F corresponding to:
C
F
=
A
c
A
o
=
c
1
-
(
1
-
c
)
(
A
o
A
d
)
2
wherein
i. A d is representative of the cross-section area of the flow region normal to the flow axis and adjacent to the damper assembly within the bounds of the inward facing surface, and
ii. c is representative of, for an inviscid fluid flowing through a relatively small aperture in a relatively large plate in response to a pressure differential across the plate, a ratio of an area normal to a vena contracta of fluid flowing through the aperture, to an area of the aperture normal to fluid flow through the aperture.
91 . An orifice plate assembly according to claim 90 further comprising a flow rate processor adapted to determine the flow rate Q of the fluid flowing through the downstream region, wherein
Q
=
(
A
c
A
o
)
A
o
2
Δ
P
ρ
=
C
F
A
o
2
Δ
P
ρ
where
i. ρ is representative of the density of the fluid, and
ii. ΔP is representative of the differential pressure along the flow axis across the damper assembly.
92 . An orifice plate assembly according to claim 91 , wherein:
i. the sensed upstream pressure is a static pressure SP upstream at the upstream pressure sense locus, and ii. the sensed downstream stream pressure is a static pressure SP downstream at the at least one downstream pressure sense locus.
93 . An orifice plate assembly according to claim 92 wherein ΔP=SP upstream −SP downstream .
94 . An orifice plate system according to claim 93 wherein C is a discharge coefficient C d corresponding to:
C
d
=
c
[
1
-
(
1
-
c
)
2
(
A
o
A
d
)
2
]
wherein
i. A d is representative of the cross-section area of the flow region normal to the flow axis and adjacent to the damper assembly within the bounds of the inward facing surface, and
ii. c is representative of, for an inviscid fluid flowing through a relatively small aperture in a relatively large plate in response to a pressure differential across the plate, a ratio of an area normal to a vena contracta of fluid flowing through the aperture, to an area of the aperture normal to fluid flow through the aperture.
95 . An orifice plate assembly according to claim 94 further comprising a flow rate processor adapted to determine the flow rate Q of fluid flowing through the downstream region, wherein
Q
=
C
d
A
o
[
1
-
(
A
o
A
d
)
2
]
2
Δ
P
ρ
where
i. ρ is representative of the density of the fluid, and
ii. ΔP is representative of the differential pressure along the flow axis across the damper assembly
96 . A method of characterizing an orifice plate assembly for a fluid of interest wherein the orifice plate assembly is adapted for disposition within an inward-facing tubular wall extending along a flow axis from an upstream end to a downstream end, and includes:
A. a damper assembly traversing the inward-facing tubular wall and including downstream-facing surfaces defining an array of one or more adjustable cross section apertures defining a corresponding array of fluid flow paths therethrough, wherein the array of apertures is characterized by an aggregate area A o corresponding to an aggregate of the aperture areas normal to the respective flow paths, B. at least one upstream pressure sensor adapted to determine total pressure at at least one upstream pressure sense locus upstream of the damper assembly wherein the upstream pressure sense locus is between and spaced apart from the array of apertures and the upstream end, C. at least one downstream pressure sensor adapted to determine static pressure at at least downstream pressure sense locus downstream of the damper assembly wherein the at least one downstream pressure sense loci are pneumatically coupled and extend from the downstream-facing surfaces defining the array of apertures and toward the downstream end, D. an actuator assembly adapted for adjustably controlling the aggregate area A o , and E. a processor configured for feedback operation of the assembly in a closed-loop, to effect operation as an orifice plate,
wherein processor is responsive to:
i. the at least one upstream pressure sensor and the at least one downstream pressure sensor to determine differential pressure ΔP across the damper assembly, and
ii. the actuator assembly to determine the aggregate area A o of the respective apertures normal to the flow paths of fluid flowing therethrough,
to control one or both of the differential pressure and the aggregate area A o in a closed-loop manner so that fluid flowing between the array of apertures and the downstream end, is characterized by a corresponding array of vena contractae, whereby a set point for a parameter of interest in a predetermined range PI R is attained,
comprising the steps of: (1) passing the fluid of interest through the orifice assembly from the upstream end to the downstream end, at a succession of n values of the parameter of interest in the predetermined range PI R , where n is an integer, (2) for each of the n values of the parameter of interest in the predetermined range PI R , selectively varying ΔP within a pressure range P R and A o within an aperture range A R while maintaining the value of the parameter of interest constant, and determining a table of k i values for ΔP and I j values for A o , for combinations of the k i values and I j values within their respective ranges P R and A R , whereby the values in the n tables characterize the parameter of interest over the ranges PI R , P R and A R .
96 . A method of conforming a characteristic performance of a fluid assembly corresponding at least in part structurally to the orifice plate assembly of claim 96 , including:
A. a damper assembly structurally similar to the damping assembly of the orifice plate assembly of claim 96 , B. an actuator assembly functionally similar to the damping assembly of the orifice plate assembly of claim 96 , C. a processor configured for feedback operation of the fluid assembly to effect operation as an orifice plate, comprising the steps of: by the processor, executing instructions for controlling operation to selectively gain access to the n tables of claim 96 and, in response thereto, controlling one or both of the differential pressure and the aggregate area A o of the fluid assembly to simulate corresponding activity of an orifice plate assembly of claim 96 , thereby conforming characteristic performance of the fluid assembly to that of the orifice plate assembly of claim 96 .
97 . A fluid assembly for a fluid of interest wherein the fluid assembly is adapted for disposition within an inward-facing tubular wall extending along a flow axis from an upstream end to a downstream end, and includes:
A. a damper assembly traversing the inward-facing tubular wall and including downstream-facing surfaces defining an array of one or more adjustable cross section apertures defining a corresponding array of fluid flow paths therethrough, wherein the array of apertures is characterized by an aggregate area A o corresponding to an aggregate of the aperture areas normal to the respective flow paths, B. an actuator assembly adapted for adjustably controlling the aggregate area A o , and C. a memory storing n differential pressure ΔP and aggregate area A o data tables for an orifice plate assembly disposed within an inward-facing tubular wall extending along a flow axis from an upstream end to a downstream end, and comprising a damper assembly structurally similar to that of the fluid assembly, wherein the differential pressure ΔP and aggregate area A o of the n data tables for the orifice plate assembly are obtained by
a. passing the fluid of interest through the orifice plate assembly from the upstream end to the downstream end, at a succession of n values of a parameter of interest in the predetermined range PI R , where n is an integer,
b. for each of the n values of the parameter of interest in the predetermined range PI R , selectively varying ΔP within a pressure range P R and A o within an aperture range A R while maintaining the value of the parameter of interest constant, and determining a table of k i values for ΔP and I j values for A o , for combinations of the k i values and I j values within their respective ranges P R and A R ,
wherein one or both of the differential pressure and the aggregate area A o is controlled in a closed-loop manner so that fluid of interest flowing between the array of apertures and the downstream end of the orifice plate assembly, is characterized by a corresponding array of vena contractae, whereby a set point for a parameter of interest in a predetermined range PI R is attained, whereby the values in the n data tables characterize the parameter of interest over the ranges PI R , P R and A R for the fluid of interest, and
D. a processor configured to effect operation of the fluid assembly as an orifice plate, wherein processor includes instructions for control of its operation to selectively gain access to the n data tables of the memory and, in response thereto, control one or both of the differential pressure and the aggregate area A o of the fluid assembly so that fluid of interest flowing through the fluid assembly between the array of apertures and the downstream end, is characterized by a corresponding array of vena contractae, whereby a set point for a parameter of interest in a predetermined range PI R is attained.Join the waitlist — get patent alerts
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