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

A device used in making differential measurements of a flow includes a flow obstruction and a support arm. The flow obstruction's forward portion is a nose cone. The flow obstruction's aft portion is coupled to the nose cone. The support arm's first end is coupled to an exterior wall of a conduit, and its second end is coupled to the forward portion of the flow obstruction. The support arm positions the flow obstruction in the conduit such that a flow region is defined around its nose cone, and such that the support arm's first and second end are separated from one another with respect to a length dimension of the conduit. Measurement ports are provided in the support arm and flow obstruction. Manifolds extending through the flow obstruction and support arm couple the ports to points at the exterior wall of the conduit.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application is co-pending with one related patent application entitled “SELF-CONTAINED TUBULAR 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 a flow obstruction and a support arm. The flow obstruction has a forward portion and an aft portion. The forward portion consists of a nose cone having a minimum-radius tip at one end thereof and a maximum-radius tail at another end thereof. The aft portion is coupled to the maximum-radius tail. The support arm has a first end coupled to an exterior wall of a conduit, and a second end coupled to the forward portion of the flow obstruction. The support arm positions the flow obstruction in the conduit such that a flow region is defined around its maximum-radius tail, and such that 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. A second manifold is formed in the flow obstruction and the support arm. The second manifold is in fluid communication with each downstream measurement port. The 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 duct or 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 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 region16is 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 region16. 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.

Obstruction14has a forward portion14A defining a nose cone shape facing fluid flow102and an aft portion14B coupled to forward portion14A and downstream thereof with respect to the flow direction of fluid flow102. The delineation between forward portion14A and portion14B is indicated in the figure by dashed line15. The particular geometry of the nose cone shape is not a limitation of the present invention provided that the upstream tip14C thereof defines the minimum radius of forward portion14A and the downstream end of forward portion14A defines the maximum radius thereof. Accordingly, upstream tip14C could be pointed, rounded, blunt, etc., without departing from the scope of the present invention. Further, the external shape of forward portion14A between tip14C and the end thereof at delineation line15can be conical, bi-conical, elliptical, concave, convex, etc., without departing from the scope of the present invention.

As fluid flow102moves past obstruction14, the fluid is compressed. To compress fluid flow102evenly thereabout (or nearly so), support arm12positions obstruction14such that tip14C and the remainder of forward portion14A are centrally positioned in conduit100. To facilitate measurement of attributes of fluid flow102so-compressed at region16, one or more measurement ports in obstruction14can be positioned at location(s) aligned with the maximum radius portion of forward portion14A at delineation line15or at locations downstream thereof. In the illustrated embodiment, a number of ports14E are formed in forward portion14A at delineation line15. More specifically, ports14E are distributed circumferentially about forward portion14A so that each port14E faces compressed-flow region16along delineation line15. Referring additionally toFIG. 5, ports14E are in fluid communication with a single manifold14F that provides fluid communication between ports14E and support arm end12A at arrangement20. That is, manifold14F extends through forward portion14A and support arm12. By providing ports14E annularly about forward portions14A and linking them to manifold14F, 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.

Typically, another sensor202is positioned outside of conduit100and in fluid communication with manifold14F. Sensor202is used to collect downstream/compressed-flow information concerning fluid flow102. Similar to sensor200, sensor202can be a pressure sensor, strain gauge, fiber optic sensor, etc., and can be used in conjunction with a temperature sensor.

Aft portion14B of obstruction14can be shaped in a variety of ways without departing from the scope of the present invention. For example, in the illustrated embodiment, the outer shape of aft portion14B is substantially the mirror image of forward portion14A with respect to delineation line15. However, the present invention is not so limited as the outer shapes of aft portion14B could be altered in a way designed to minimize turbulence, pressure loss, etc., or create/induce some secondary movement/action in fluid flow102moving past aft portion14B.

The present invention can also be adapted to facilitate the measurement of attributes of fluid flow102inside of compressed-flow region16or at the central portion of conduit100. For example, as illustrated inFIG. 6, a longitudinal flow through channel14G could be formed through the longitudinal center of obstruction14. Another manifold14H is provided in fluid communication with channel14G where manifold14H extends up to arrangement20where another sensor204can be used for data measurement.

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.