Self-contained tubular compressed-flow generation device for use in making differential measurements

A device used in making differential measurements of a flow includes an open-ended tubular flow obstruction and a support arm. The flow obstruction has an outer annular wall and an inner annular wall. The support arm has a first end coupled to an exterior wall of a conduit and a second end coupled to the flow obstruction. The support arm positions the flow obstruction in the conduit such that a first flow region is defined around the flow obstruction's outer annular wall and a second flow region is defined by the flow obstruction's inner annular wall. The support arm's first end and second end are separated from one another with respect to a length dimension of the conduit. Measurement ports provided in the flow obstruction are coupled to points at the exterior wall of the conduit by manifolds extending through the flow obstruction and support arm.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application is co-pending with one related patent application entitled “SELF-CONTAINED COMPRESSED-FLOW GENERATION DEVICE FOR USE IN MAKING DIFFERENTIAL MEASUREMENTS”, filed by the same inventors and owned by the same assignee as this patent application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to flow measurement tools. More specifically, the invention is a self-contained device that generates compressed flow in a conduit for use in making differential measurements in a flow.

2. Description of the Related Art

For a variety of reasons, devices are needed that can be adapted to an existing fluid conduit for the temporary or permanent provision of specific functions. One such function is the measurement of a parameter of a flowing fluid. Other functions include mixing the flowing fluid and/or injecting a second fluid into the (main) flowing fluid. With respect to parameter measurement, attributes of interest include pressure, velocity, density, temperature, etc. Currently, many flow “measurement” devices collect flow information that is then used in some approximation or modeling scheme to estimate flow attributes. In addition, current flow measurement devices are installed by cutting fully through existing conduits and then “splicing” the flow measurement devices into the conduit. This can be time consuming, tedious, and costly. This is especially problematic when making differential measurements (i.e., at two spaced apart locations along a conduit) as multiple devices must be spliced into a conduit with the entire installation then requiring calibration to account for installation irregularities. Still further, current differential flow measurement devices can create substantial pressure losses effecting pump efficiency. Flow measurement devices can also be the source of a blockage in a conduit when solids and/or foreign matter are present in a flowing fluid (e.g., man-made debris, natural debris such as hair, sticks, leaves, etc.). For example, a flow measurement device such as an orifice plate is readily clogged with debris thereby impacting flow measurements and the flow itself.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a device that can be used when making differential measurements in a flowing fluid.

Another object of the present invention is to provide a device that can be readily installed in an existing conduit or duct in preparation for making differential measurements of a fluid flow moving through the conduit.

Still another object of the present invention is to provide a flowing-fluid differential measurement-supporting device that is resistant to clogging.

In accordance with the present invention, a compressed-flow generation device for use in making differential measurements of flow attributes includes an open-ended tubular flow obstruction and a support arm. The flow obstruction has an outer annular wall and an inner annular wall. The outer annular wall is shaped to define a maximum radius portion of the flow obstruction, and the inner annular wall is shaped to define a minimum radius portion of the flow obstruction. A support arm has a first end and a second end with the first end coupled to an exterior wall of a conduit and the second end coupled to the flow obstruction. The support arm positions the flow obstruction in the conduit such that a first flow region is defined around the flow obstruction's outer annular wall and a second flow region is defined by the flow obstruction's inner annular wall. The support arm's first end and second end are separated from one another with respect to a length dimension of the conduit. At least one upstream measurement port is formed in the support arm. A first manifold is formed in the support arm and is in fluid communication with each upstream measurement port. The first manifold terminates and is accessible at the exterior wall of the conduit. At least one downstream measurement port is formed in the flow obstruction with each downstream measurement port being in fluid communication with one of the first flow region and the second flow region. At least one second manifold is formed in the flow obstruction and support arm. Each second manifold is in fluid communication with each downstream measurement port so-communicating with one of the first flow region and the second flow region. Each second manifold terminates and is accessible at the exterior wall of the conduit.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Referring now to the drawings, simultaneous reference will be made toFIGS. 1-5where a variety of views of a self-contained device for generating a compressed flow in a conduit to facilitate the collection of differential measurements in accordance with an embodiment of the present invention is shown and is referenced generally by numeral10. Device10is positioned/mounted in a conduit100that carries a flowing fluid moving in a known direction where such fluid and its flow direction are indicated by arrows102. The terms “upstream” and “downstream” as used herein are referenced to the flow direction of fluid flow102. Fluid flow102can be a gas, vapor, a pure liquid, or a gas or liquid mixed with some solids that are present by design or by circumstance. For example, fluid flow102could contain natural or man-made debris that must pass through conduit100and past device10to maintain flow efficiency.

In general, device10is a self-contained device that positions measurement ports in fluid flow102in a pre-determined and definitive manner such that differential measurements concerning flow102can be made easily and precisely. Device10includes a support arm12and a compressed-flow-generating obstruction14. Obstruction14is positioned in fluid flow102by support arm12such that fluid flow102is compressed in a region16around obstruction14and in a region18extending through obstruction14. Measurement ports are provided in both support arm12and obstruction14to facilitate differential measurements concerning fluid flow102. That is, one or more measurement ports are located in support arm12where fluid flow102is not compressed, and one or more measurement ports are located in obstruction14where fluid flow102is compressed to thereby create a differential measurement environment.

Support arm12and obstruction14can be separate elements coupled to one another or they can be formed as an integrated device (e.g., molded as one piece). In either case, device10can be installed as part of conduit100or can be installed in an existing conduit100. In terms of an existing conduit100, an installation/entry aperture (indicated by dashed line100A) is cut in conduit100. Aperture100A is sized/shaped to receive support arm12and obstruction14therethrough. Once positioned in conduit100, device10is coupled and sealed to conduit100by means of a mounting/sealing arrangement20, the design of which is not a limitation of the present invention. Since conduit100need only have a simple aperture100A cut therein, the overall integrity, shape, and size of conduit100is maintained such that device10has little or no impact on the existing system.

In general, support arm12is shaped to position obstruction14such that the above-described compressed flow regions16and18are downstream (with respect to the flow direction of fluid flow102) of an upstream portion of support arm12. For example, in the illustrated embodiment, support arm12defines a smooth arcuate shape along its length with its upstream end12A coupled to conduit100by mounting/sealing arrangement20. The downstream end12B of support arm12is coupled to obstruction14with downstream end12B blending smoothly into obstruction14to minimize turbulence at this interface. The leading edge12C of support arm12facing into the oncoming fluid flow102can be tapered as illustrated inFIG. 3to reduce or eliminate the capture of any debris (not shown) present in fluid flow102. In other embodiments, leading edge12A and trailing edge12D of support arm12can be rounded or otherwise shaped to minimize turbulence as fluid flow102goes by while also providing the necessary structural integrity to support obstruction14.

As mentioned above, one or more measurement ports are provided in support arm12at a location(s) that is upstream of compressed-flow regions16and18. In the illustrated embodiment, a single port12E (also shown inFIG. 4) is located at leading edge12C. However, it is to be understood that the upstream port(s) could be located near leading edge12C without departing from the scope of the present invention. A manifold12F formed in support arm12provides fluid communication between port12E and end12A at arrangement20. Typically, a sensor200is positioned outside of conduit100and is fluid communication with manifold12F. Sensor200is used to collect upstream (i.e., non-compressed) information concerning fluid flow102. Sensor200can be a pressure sensor, strain gauge, fiber optic sensor, etc., and can be used in conjunction with a temperature sensor.

Obstruction14is an open-ended tube with its outer annular wall14A facing the inside wall of conduit100to thereby define compressed flow region16, and with its inner annular wall14facing/defining compressed flow region18. In general, when looking at a longitudinal cross-section of obstruction14between flow regions16and18, each of walls14A and14B is defined by a curvilinear shape. By virtue of each wall's curvilinear shape, some portion of outer annular wall14A forms the largest radius of obstruction14while some portion of inner annular wall14B forms the smallest radius of obstruction14. The radius of obstruction14is measured with respect to the central longitudinal axis of obstruction14that is indicated by dashed line14C. For the illustrated embodiment, mirror-imaged convex curves define the shape of walls14A and14B when looking at a longitudinal cross-section of obstruction14between flow regions16and18. Accordingly, the maximum radius portion and minimum radius portion of obstruction14are longitudinally aligned with one another. As a result, maximum compression of fluid flow102in regions16and18occurs at the same longitudinal regions of obstruction14and conduit100. However, as will be explained further below, the present invention is not so limited as the curvilinear shapes of walls14A and14B can be different (i.e., not mirror images of one another) without departing from the scope of the present invention.

As fluid flow102moves past obstruction14, the fluid is compressed in regions16and18. To compress fluid flow102evenly thereabout (or nearly so), support arm12positions obstruction14such that longitudinal axis14C is centrally positioned (or nearly so) in conduit100. To facilitate measurement of attributes of fluid flow102so-compressed at regions16and/or18, one or more measurement ports in obstruction14can be positioned at location(s) in fluid communication with region16or region18. For example, in the illustrated embodiment, a number of ports14E are formed in outer annular wall14A at the maximum radius portion of obstruction14, and a number of ports14F are formed in inner annular wall14B at the minimum radius portion of obstruction14. More specifically in the illustrated embodiment, ports14E are distributed (e.g., evenly) circumferentially about outer annular wall14A to face compressed flow region16. Similarly, ports14F are distributed (e.g., evenly) about inner annular wall14B to face compressed flow region18.

Referring additionally toFIG. 5, ports14E are in fluid communication with a single manifold14G that provides fluid communication between ports14E and support arm end12A at arrangement20. That is, manifold14G extends through obstruction14and support arm12. By distributing ports14E annularly about outer annular wall14A and linking them to manifold14G, the attributes of fluid flow102at region16are averaged. It should be noted that the number/locations of the ports can be dependent on a variety of factors such as the fluid's velocity, density, etc. Accordingly, the number and locations of ports14E can be varied from those shown without departing from the scope of the present invention.

In similar fashion, ports14F are in fluid communication with a single manifold14H that provides fluid communication between ports14F and support arm end12A at arrangement20. That is, manifold14H also extends through obstruction14and support arm12. Distribution of ports14F around inner annular wall14B and the linking of them to manifold14H results in the averaging of the attributes of fluid flow102at region18. The number and location of ports14F can be varied from the illustrated embodiment without departing from the scope of the present invention.

Separate sensors202and204are positioned outside of conduit100and in fluid communication with manifolds14H and14G, respectively. Each sensor is used to collect downstream/compressed-flow information concerning fluid flow102in either region16or region18. Similar to sensor200, each of sensors202and204can be a pressure sensor, strain gauge, fiber optic sensor, etc., and can be used in conjunction with a temperature sensor. Sensors202and204enable flow accuracy optimization over an extended flow range and enable calculation of various properties such as density, viscosity, etc.

The portions of obstruction14downstream of its measurement ports can be shaped in a variety of ways without departing from the scope of the present invention. For example, the portion of obstruction14downstream of its measurement ports can be shaped to minimize turbulence, pressure loss, etc. In other applications, the portion of obstruction14downstream of its measurement ports could be shaped to create/induce some secondary movement/action in fluid flow102as it passes obstruction14.

As mentioned above, the present invention is not limited to the mirror-image convex curvilinear shapes of walls14A and14B described herein. Accordingly,FIG. 6illustrates another embodiment of the present invention where support arm12is coupled to an open-ended tubular flow obstruction24has an outer annular wall24A and an inner annular wall24B. Outer annular wall24A faces flow region16flowing around obstruction24while inner annular wall24B defines flow region18passing through obstruction24. A longitudinal cross-section of obstruction24between flow regions16and18defines an airfoil shape where outer annular wall24A forms the low-pressure side of the airfoil shape and inner annular wall24B forms the high-pressure side of the airfoil shape. Note that the airfoil shape could be reversed such that the low-pressure side of the airfoil faced region18and the high-pressure side of the airfoil shape faced region16. In either case, the resulting lift effect is useful to provide a lower absolute pressure along the low-pressure side, at and beyond the maximum radius portion, thereby increasing the measurable delta pressure between the upstream port and the downstream port at the low-pressure side and between the high-pressure and low-pressure side of the airfoil. This increases the measured flow signal which increases measured flow resolution. As a result, higher precision sensors are not needed at low flow rates, or conversely, the measurement device is more efficient and will have less impact on the flow in terms of permanent pressure losses and the device will operate over a larger fluid flow range.

Similar to the previously-described embodiment, one or more measurement ports can be formed in one or both walls24A and24B with corresponding manifolds being provided/defined within obstruction24and support arm12. For example, ports24C in wall24A are located at the maximum radius portion of obstruction24, and ports24D in wall24B are located downstream of ports24C. One manifold24E is in fluid communication with ports24C and another manifold24F is in fluid communication with ports24D. Each manifold leads to a sensor (i.e., manifold24F leads to sensor202and manifold24E leads to sensor204) at the exterior of conduit100as in the previously-described embodiment.

The advantages of the present invention are numerous. The self-contained device will provide for multiple differential measurements in a fluid flow. The device is easily installed in existing conduits and does not disturb the basic conduit installation or structural integrity. The device's measurements ports are fixed/known ‘a priori’ thereby eliminating the need for calibration at each installation. The device is configured to greatly reduce or eliminate the possibility of being clogged with foreign matter and debris and will, therefore, require little or no maintenance and will not impact flow/pump efficiencies. The multiple differential measurement locations enable flow cross-checking to evaluate proper instrumentation function and to calculate flowing fluid properties such as density, viscosity, etc.