Description:A DEVICE FOR REDUCING PRESSURE DROP IN A HOT AIR DUCT

FIELD OF THE INVENTION
[0001] The present subject matter described herein relates to measurement of flow of a measuring fluid in an industrial process. More specifically, the present invention relates to a flow measuring device that reduces the unrecoverable pressure drop in a hot air duct due to presence of cylindrical tubes. It improves accuracy of measurement by creating higher recoverable pressure drop of the measuring fluid.

BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Air flow rate in power plants is computed by placing a primary element that restricts the flowing stream causing an increase in velocity and reduction in static pressure in the flow through the primary element. Then the flow stream is allowed to return to normal flow conditions. The resulting difference in pressure across the primary element and the normal flow pressure is measured using differential pressure sensors or transmitters. By measuring the pressure head or drop, one can compute the velocity using the Bernoulli’s equation. The volumetric or mass flow rates can be computed from the velocity.
[0004] Typically, in power plants, an airfoil is used the as primary element for measurinf flow rates of secondary air. Alternatively, other flow measuring primary elements including orifice, venturi meter, that were used to measure secondary air flow. Any air flow measuring device should be accurate, reliable and exhibit repeatability. The airfoil has some disadvantages like being bulky, more difficult and more cost for transporting and erecting, causing a higher unrecoverable pressure drop, requirement of considerable straight lengths before and after for streamlining the flow. The fans in the power plant are to be sized to cater to the higher unrecoverable pressure drop in secondary air duct caused by flow measuring device.
[0005] As an alternative, pitot tubes can be used for measuring airflow. The basic pitot tube consists of a tube pointing directly into the fluid flow. It is similar to a blunt object placed in the path of the flow stream, which stops the flow. The moving fluid is brought to rest as there is no outlet to allow flow to continue. As this tube contains fluid, a pressure can be measured at this point of zero flow. This pressure is the stagnation pressure of the fluid, also known as the total pressure. The static pressure is measured at a point in the duct with undisturbed flow. The difference between the two pressure is used in determining the flow using Bernoulli’s equation. However, a single pitot tube cannot accurately measure flow in large ducts, where the flow across the cross section is not uniform.
[0006] US9702743B2 describes a flowmeter for measuring flow of a process fluid through a conduit including upstream and downstream process variable sensors mounted on the pitot tube. The invention comprises of two process variable transmitters configured as a flowmeter for measuring flow of a process fluid through a conduit. The transmitter includes a pitot tube extending into the conduit which creates a differential pressure in the process fluid due to flow of the process fluid. An upstream process variable sensor is mounted on the pitot tube and coupled to the flow of process fluid to sense an upstream process variable of the process fluid. A downstream process variable sensor is mounted on the pitot tube downstream of the upstream process variable sensor and coupled to the flow of process fluid to sense a downstream process variable of the process fluid. Measurement circuitry determines the flow of the process fluid based upon the upstream process variable and the downstream process variable.
[0007] US7258024B2 describes a simplified fluid property measurement system like differential pressure measurement or a vortex flow meter having configurable terminations for coupling to a variety of pressure or differential pressure sensors or transmitters for advanced process fluid measurements or calculations. An additional measurement of process fluid flow velocity in the pipe is combined with the first measurement to provide a simplified indication of mass fluid flow and/or density or other fluid parameters.
[0008] US20110303019A1 describes an apparatus and a method of monitoring multiphase fluid flow passing within a pipe. The method includes providing a flow pressure value and a flow temperature value for the multiphase fluid flow within the pipe, sensing the fluid flow with a fluid flow meter operable to be attached to an exterior of the pipe, the flowmeter including a spatial array of at least two sensors disposed at different axial positions along the pipe, and producing flow velocity signals indicative of a velocity of the fluid flow traveling within the pipe, selectively injecting at least one tracer into the fluid flow passing within the pipe, at a known injection flow rate and concentration, sensing a sample of the fluid flow for the tracer, and producing tracer concentration signals indicative of the concentration of the tracer in the fluid flow and determining one or more of a gas component flow rate, an oil component flow rate, and a water component flow rate, using one or more of the flow pressure value, the flow temperature value, the flow velocity signals, and the tracer concentration signals.
[0009] The prior arts have certain drawbacks that restrict their use for continuous air flow measurements in ducts with high aspect ratio in a thermal power plant firing high ash containing coal.
[0010] Thus there exists a need for a flow measuring device that takes care of the above problem with minimal unrecoverable pressure drop and simpler and cheaper construction.

OBJECTS OF THE DISCLOSURE
[0011] It is therefore the object of the present disclosure to overcome the aforementioned and other drawbacks in prior arts.
[0012] It is a primary object of the present disclosure to provide a device for reducing unrecoverable pressure drop in a hot air duct due to presence of cylindrical tubes.
[0013] It is another object of the present disclosure to simplify the design of the flow measuring device by using readily available cylindrical tubes.
[0014] It is another object of the present disclosure to provide the flow measuring device which uses an array of tubes distributed at equal intervals across the cross section of larger ducts.
[0015] It is another object of the present disclosure to provide a modularized design to increase the number of modules of the airflow measuring device in case of wider ducts.
[0016] It is another object of the present disclosure to improve the induced flow pressure drop of the measuring fluid to obtain greater accuracy in the flow measurement.
[0017] It is another object of the present disclosure to provide an optimization of stagnation tube cut-off angle, tube size, upstream and downstream lengths.
[0018] These and other objects and advantages of the present subject matter will be apparent to a person skilled in the art after consideration of the following detailed description taken into consideration with accompanying drawings in which preferred embodiments of the present subject matter are illustrated.

SUMMARY OF THE INVENTION
[0019] One or more drawbacks of conventional systems and process are overcome, and additional advantages are provided through the apparatus/composition and a method as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be part of the claimed disclosure.
[0020] Solution to one or more drawbacks of existing technology and additional advantages are provided through the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be a part of the claimed disclosure.
[0021] The present disclosure offers a solution in the form of a flow measuring device for for reducing unrecoverable pressure drop in a hot air duct due to presence of cylindrical tubes. The device comprising of a hollow housing installed inside the hot air duct having an inlet and an outlet, an average total pressure tap and an average static pressure tap are located at an intermediate point on top of the hollow housing. An interconnected manifold connected to the average total pressure tap and the average static pressure tap. A multitude cylindrical pitot tubes arranged in a traversing direction in an interior cross sectional area of the hollow housing, wherein the cylindrical pitot tubes are anchored to the interconnected manifold, multiple sensing ports provided at ends of the plurality of cylindrical pitot tubes traversing in an interior cross sectional area of the hollow housing and a plurality of static pressure sensing ports connected to the interconnected manifold and extended in a transverse direction.
[0022] In an aspect of the invention, the average total pressure tap and the average static pressure tap protrude outward from the hollow housing at a top end.
[0023] In a further aspect of the invention, a cut off angle (α) is provided for the static pressure measuring port.
[0024] In an aspect of the invention, an angle (β) is maintained between the plurality of cylindrical pitot tubes and the interconnected manifold.
[0025] In an aspect of the invention, the static pressure sensing ports are arranged in fluid communication with average static pressure tap through a static pressure tube.
[0026] In an aspect of the invention, the plurality of pressure sensing ports have an inclined opening that faces the flow.
[0027] In an aspect of the invention, the plurality of total pressure sensing ports are provided at ends of the plurality of cylindrical pitot tubes.
[0028] In an aspect of the invention, each cylindrical pitot tube is formed of multiple pitot tubes.
[0029] In an aspect of the invention, an interconnect header is used for connecting multiple pitot cylindrical pitot tubes including multiple average static pressure taps and multiple average total pressure taps.
[0030] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
[0031] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
[0032] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.
[0033] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0034] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein:-
[0035] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the present disclosure may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods or structure in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0036] Fig. 1 and 2 illustrate a flow measuring device in accordance to the present invention;
[0037] Fig. 3 illustrates a side elevation view of the flow measuring device in accordance to the present invention;
[0038] Fig. 4 illustrates a top view of the flow measuring device in accordance to the present invention;
[0039] Fig. 5 illustrates a tube of the flow measuring device in accordance to the present invention;
[0040] Fig. 6 illustrates static pressure tubes of the flow measuring device in accordance to the present invention;
[0041] Fig. 7 illustrates an embodiment in accordance to the present invention.
[0042] Fig. 8 illustrates an embodiment in accordance to the present invention.
[0043] A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
[0044] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAIL DESCRIPTION OF INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS OF THE PREFERRED EMBODIMENTS:
[0045] While the embodiments of the disclosure are subject to various modifications and alternative forms, a specific embodiment thereof has been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.
[0046] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that a device, system, assembly that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device. In other words, one or more elements in a system or device proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or device.
[0047] The present invention is related to an flow measuring device reducing unrecoverable pressure drop in a hot air duct due to presence of cylindrical tubes. The flow measuring device is lesser in weight and the problem of choking of pressure tapping lines is eliminated.
[0048] Referring to Figs. 1-4. a flow measuring device (100) is provided. The flow measuring device (100) includes a hollow housing (1) that is installed inside a hot air duct. The flow measuring device (100) is symmetrical to the axis of the pitot head. The hollow housing (1) has an inlet (2) and an outlet (3), wherein an average total pressure tap (17) and an average static pressure tap (18) are located at an intermediate point on top of the hollow housing (1). The hollow housing (1) has a vertical dimension (W) and a horizontal dimension (H).
[0049] The hollow housing (1) is made with same vertical internal dimensions as hot air duct in which it is to be utilized. The average total pressure tap (17) and the average static pressure tap (18) are protruded outwards from the hollow housing (1) at a top end.
[0050] Further, a plurality of cylindrical pitot tubes (4, 5, 6, 7, 8, 9) are arranged in a tranverse direction in an interior cross sectional area of the hollow housing (1). Further, a plurality of total pressure sensing ports (11, 12, 13, 14) are provided at ends of the plurality of cylindrical pitot tubes (4, 5, 6, 7, 8, 9).
[0051] The plurality of total pressure sensing ports (11, 12, 13, 14) also traverse in an interior cross sectional area of the hollow housing (1). The plurality of cylindrical pitot tubes (4, 5, 6, 7, 8, 9) have an inclined opening where one end, the plurality of total pressure sensing ports (11, 12, 13, 14) are arranged. The inclined opening faces the air flow and traversing equal areas in the interior cross sectional area of the hollow housing (1) for sensing the total pressure of fluid flowing into the hot air duct.
[0052] The plurality of cylindrical pitot tubes (4, 5, 6, 7, 8, 9) are affixed to an interconnected manifold (10) by welding. A connecting tube angle (β) is between the cylindrical pitot tubes (4, 5, 6, 7, 8, 9) and the interconnected manifold (10).
[0053] The plurality of cylindrical pitot tubes (4, 5, 6, 7, 8, 9) are connected to a head pitot through the interconnected manifold (10) and cross pipes of interconnected manifold (10) and three averaging total pressure pipes (15, 16), two averaging total pressure pipes (15) on sides and one averaging total pressure pipe (16) at a central pipe.
[0054] Also, the static pressure sensing ports (19) are affixed such that their opening is parallel to the flow and traversing the interior cross sectional area of the hollow housing (1) along the width of the hollow housing (1) for sensing the static pressure within the hot air duct. The static pressure sensing ports (19) measures the static pressure within the hot air duct. The static pressure sensing ports (19) are more clearly shown in Fig. 6.
[0055] The static pressure measuring ports (19) are made in such a way to measure static pressure are at the same level as an opening. These connections allow for the use of a differential pressure instrument for computing average flow rate and/or transmitting a flow rate signal.
[0056] The device allows for pitot tube flow principles to be utilized, by sensing the averaged total pressure of the flowing gas with the total pressure sensing ports (11, 12, 13, 14) and the average static pressure within the hot air duct with the static pressure sensing ports (19).
[0057] Further, the total pressure ports (11, 12, 13, 14) and the static pressure sensing ports (19) are not placed randomly within the hot air duct, rather the total pressure ports (11, 12, 13, 14) and the static pressure sensing ports (19) are meticulously placed in a traversing manner. The total number and location of sensing ports are positioned in accordance with the following guidelines.
[0058] The hollow housing (1) is divided into sixteen equal areas as shown in Fig. 8 and the location of static pressure sensing ports (19) and the total pressure ports (11, 12, 13, 14) are placed in traversing manner such that a total pressure port (11, 12, 13, 14) is present at a centre of each of these areas.
[0059] The dimensions of the flow measuring device depends on the size of the hot air duct and has been taken as the following optimum parameter as per the performance evaluation conducted in Computational Fluid Dynamics (CFD) simulation:
• The optimized size for the plurality of cylindrical pitot tubes (4, 5, 6, 7, 8, 9) of each module according to both vertical (W) and horizontal (H) dimensions of the hot ait duct and to ensure blockage ratio between 10 to 25%.
• The optimized size for the plurality of cylindrical pitot tubes (4, 5, 6, 7, 8, 9) range from 60 to 65 mm.
• The optimum cut off angle of (α) is used for the static pressure sensing port (19).
[0060] The length of the plurality of cylindrical pitot tubes (4, 5, 6, 7, 8, 9) are kept same and is geometrically calculated as a function of vertical dimension W of the duct. The outer diameter of the plurality of cylindrical pitot tubes (4, 5, 6, 7, 8, 9) has an angle of cutting (α) w.r.t to vertical axis.
[0061] Fig. 3 shows the location of the total pressure sensing sports (11, 12, 13 and 14) and the static pressure ports (19) on the plurality of cylindrical pitot tubes (4, 5, 6, 7, 8, 9) and the interconnected manifolds (10).
[0062] Fig. 5 shows the location of interface ports (52) in the cylindrical pitot tubes (4, 5, 6, 7, 8, 9) for the interconnected manifolds (10) is shown. The first view is normal to the flow and right hand side view for Fig. 2 and other 3 figures are 90° clockwise rotational views of thereof. The location of interface ports (52) in the cylindrical pitot tubes (4, 5, 6, 7, 8, 9) has been optimized based on CFD analysis.
[0063] In addition, a left top cylindrical pitot tube (4) and a bottom row corner cylindrical pitot tube (7) have interface ports (52) on a right hand side of the cylindrical pitot tubes (4, 5, 6, 7, 8, 9) and a top row middle cylindrical pitot tube (5) and a bottom row middle cylindrical pitot tube (8) have interface ports (52) on both sides of the cylindrical pitot tubes (4, 5, 6, 7, 8, 9). A right top row corner cylindrical pitot tube (6) and a right bottom row corner cylindrical pitot tubes (8) have interface ports (52) on left hand side of the cylindrical pitot tubes (4, 5, 6, 7, 8, 9). The left top (4) and right bottom (8) cylindrical pitot tubes are inversions and similarly the right top (6) and left bottom (7) cylindrical pitot tubes are inversions.
[0064] Each total pressure sensing ports (11, 12, 13, 14) has multiple sensing ports oriented so as to face directly toward the inlet, thereby providing unrestricted fluid communication between the impacting fluid flowing into the hot air duct, through the total pressure sensing ports (11, 12, 13, 14), and to the interconnected manifold (10). The interconnected manifold (10) thereby consolidates this combined pressure and sends it to the average total pressure tap (17) as shown in Fig. 2.
[0065] Referring to Fig. 6, the static pressure sensing ports (19) are arranged in fluid communication with average static pressure tap (18) through a static pressure tube (20). The static pressure sensing port (19) has a plurality of sensing ports oriented so as to face perpendicular to the gas flow.
[0066] Referring to Fig. 7, in an embodiment, if multiple tubes (4, 5, 6, 7, 8, 9), total pressure sensing ports (11, 12, 13 and 14) and static pressure sensing ports (19) are used, an interconnect header (61) is to be provided to connect the total pressure sensing ports (11, 12, 13 and 14) and static pressure sensing ports (19) of each element.
WORKING OF THE INVENTION
The flow measuring device (100) is installed in the hot air ducts, instrument piping is installed in order to connect the average total pressure tap (17) and average static pressure tap (18) to the two ports of differential pressure transmitter for indicating the flow differential pressure (DP). This flow DP is transmitted to the control system and it is calibrated to give the flow rate.
TECHNICAL ADVANTAGES
[0067] With the help of the solution as proposed herein in the context of the present disclosure, the ash clogging is avoided.
[0068] Due to low blockage ratio and use of cylindrical tubes, the unrecoverable pressure drop is 10 times lower than that for an airfoil. Also, the induced pressure drop is higher thereby improving the measurement accuracy. Also, there is a 25% increase in flow differential pressure when compared with other pitot array designs.
[0069] The flow measuring device can be suitably extended for any duct shape, in particular, for ducts with high aspect ratio. In such cases, other pitot array based measurements do not provide equal area coverage and hence the flow measured is not accurate.
[0070] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation, no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to disclosures containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. Also, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general, such construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to “at least one of A, B, or C, etc.” is used, in general, such construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
[0071] It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present disclosure contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the disclosure, and other dimensions or geometries are possible. Also, while a feature of the present disclosure may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present disclosure. The present disclosure also encompasses intermediate and end products resulting from the practice of the methods herein. The use of “comprising” or “including” also contemplates embodiments that “consist essentially of” or “consist of” the recited feature.
[0072] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0073] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
[0074] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particulars claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogues to “at least one of A, B and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.
[0075] The above description does not provide specific details of manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.
[0076] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[0077] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[0078] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
, Claims:WE CLAIM
1. A flow measuring device (100) for reducing unrecoverable pressure drop in a hot air duct due to presence of cylindrical tubes, the device (100) comprising of:
a hollow housing (1) installed inside the hot air duct having an inlet (2) and an outlet (3), an average total pressure tap (17) and an average static pressure tap (18) located at an intermediate point on top of the hollow housing (1);
an interconnected manifold (10) connected to the average total pressure tap (17) and the average static pressure tap (18);
a plurality of cylindrical pitot tubes (4, 5, 6, 7, 8, 9) arranged in a traversing direction in an interior cross sectional area of the hollow housing (1), wherein the cylindrical pitot tubes (4, 5, 6, 7, 8, 9) are anchored to the interconnected manifold (10);
multitude of pressure sensing ports (11, 12, 13, 14) provided at ends of the plurality of cylindrical pitot tubes (4, 5, 6, 7, 8, 9) traversing in an interior cross sectional area of the hollow housing (1); and
multiple static pressure sensing ports (19) connected to the interconnected manifold (10) and extended in a transverse direction.

2. The device (100) as claimed in claim 1, wherein the average total pressure tap (17) and the average static pressure tap (18) protrude outward from the hollow housing (1) at a top end.
3. The device (100) as claimed in claims 1-2, wherein a cut off angle (α) is provided for the static pressure measuring port (19).
4. The device (100) as claimed in claims 1-3, wherein an angle (β) is maintained between the plurality of cylindrical pitot tubes (4, 5, 6, 7, 8, 9) and the interconnected manifold (10).
5. The device (100) as claimed in claims 1-4, wherein the static pressure sensing ports (19) are arranged in fluid communication with average static pressure tap (18) through a static pressure tube (20).
6. The device (100) as claimed in claims 1-5, wherein the plurality of pressure sensing ports (11, 12, 13, 14) have an inclined opening that faces the flow.
7. The device (100) as claimed in claims 1-6, wherein the plurality of total pressure sensing ports (11, 12, 13, 14) are provided at ends of the plurality of cylindrical pitot tubes (4, 5, 6, 7, 8, 9).
8. The device (100) as claimed in claims 1-7, wherein each cylindrical pitot tube (4, 5, 6, 7, 8, 9) is formed of multiple pitot tubes.
9. The device (100) as claimed in claims 1-8, wherein an interconnect header (61) may be used for connecting multiple pitot cylindrical pitot tubes (4, 5, 6, 7, 8, 9) including multiple average static pressure taps (18) and multiple average total pressure taps (17).