Pipes and tubular conduits – With flow regulators and/or baffles
Reexamination Certificate
2002-02-25
2003-02-25
Brinson, Patrick (Department: 3752)
Pipes and tubular conduits
With flow regulators and/or baffles
C138S042000, C366S336000, C366S337000, C366S338000
Reexamination Certificate
active
06523572
ABSTRACT:
FIELD OF INVENTION
The present invention relates to the induction of forces by injection of fluids through a conduit having a unique internal geometry. More particularly, it relates to an apparatus and method of fluid injection aimed at producing and employing aerodynamically induced forces.
BACKGROUND OF THE INVENTION
Injection of fluids, liquids, and in particular gases, through one conduit or a plurality of conduits, is a common mean to produce an aerodynamically induced forces acting on objects. Without derogating generality, the present invention relates commonly to the injection of air, although in general the present invention can be applied in connection with other fluids too.
In order to produce an aerodynamically induced force, interaction between the out coming flow and a nearby object must be established. As an applied pressure difference drives the fluid through the conduit, the out coming flow interacts in a perpendicular manner with an object placed further apart from the conduit outlet. When the distance between the conduit outlet and the object facing the outlet is small, in the order of 5 lateral scales of the particular conduit outlet (or more), a jet flow is generated. This jet has a momentum defined by its mass flow rate and velocity. When such a jet impinges on an object, it exerts an aerodynamically induced force on the object. This exerted force depends on the momentum of the jet, as well as on the object specific geometry. A different effect occurs when the distance between the conduit outlet and the object surface is small, in the order of 1 lateral scale of the conduit outlet (or less). In such a case, the fluid is forced to turn sideways. In this cases, the object is also subjected to aerodynamically induced force.
Alternatively, when a fluid is injected parallel to the object surface, it is possible to produce aerodynamically induced force that is substantially parallel to the fluid motion. In such cases, the direction of this essentially “parallel-to-fluid-motion” aerodynamically induced force can be altered, according to the local induced pressure that is generated on the interacting surface of the object: It can locally be higher or lower pressure with respect to the average pressure acting on the object.
The design of an injecting system that aims at producing aerodynamically induced force incorporates various aspects, (a) the applied external driving pressure difference, (b) the internal geometric details of the specific conduit of the present invention, (c) the geometry of the conduit inlet and outlet sections, (d) the specific arrangement of the conduits when a plurality of conduits are used, etc. Such aspects and many more are all taken in consideration according to the engineering requirements for a specific application.
The only related prior art references having some relevance to the present invention deal with irrigation emitters only where the fluid passing through it is water which is practically incompressible (as opposed to air or other gases).
U.S. Pat. No. 3,896,999 (Barragan) disclosed an anti-clogging drip irrigation valve, comprising a wide conduit equipped with a plurality of partition means, integrally formed with the conduit wall, forming labyrinth conduits, in order to reduce the water pressure prior to its exit through the labyrinth conduits outlet.
U.S. Pat. No. 4,573,640 (Mehoudar) disclosed an irrigation emitter unit providing a labyrinth conduit similarly to the valve in U.S. Pat. No. 3,896,999. Examples of other devices providing labyrinth conduits for the purpose of providing a pressure drop along the conduit can be found in U.S. Pat. No. 4,060,200 (Mehoudar), U.S. Pat. No. 4,413,787 (Gilead et al.), U.S. Pat. No. 3,870,236 (Sahagun-Barragan), U.S. Pat. No. 4,880,167 (Langa), U.S. Pat. No. 5,620,143 (Delmer et al.), U.S. Pat. No. 4,430,020 (Robbins), U.S. Pat. No. 4,209,133 (Mehoudar), U.S. Pat. No. 4,718,608 (Mehoudar), U.S. Pat. No. 5,207,386 (Mehoudar).
In a labyrinth conduit the aerodynamic resistance is substantially large due to the viscous friction exerted by the walls of the conduit (acting opposite to the direction of the flow), and as the passage becomes tortuous and lengthier (that's the essential feature of a labyrinth) more wall contact surface is acting on the flow, increasing the viscous friction. In some cases cavities are provided for intercepting contaminants and for freeing the flow passage. None of these patents, which basically deal with two dimensional geometry (the third being either very small or degenerated), mention or make use of a vortical aerodynamic blockage mechanism, that is an essential feature of the present invention.
It is emphasized that while the above mentioned patents deal with the delivery of water through the conduit, the present invention seeks to provide and exploit aerodynamically induced forces, with the fluid—air in most cases—merely serving as the means for generating these forces.
In an article titled “A FLOW VISUALIZATION STUDY OF THE FLOW IN A 2D ARRAY OF FINS” (S. Brokman, D Levin, Experiments in Fluids 14, 241-245 (1993)) a study of the flow field in a 2D arrangement of fins was carried out by means of flow visualization in a vertical flow tunnel. The study was related to an earlier studies that examined the fin arrangement as a conceptual heat sink. The above mentioned study went further to examine the complex flow field structure in order to obtain a better understanding of the heat convection process. A model was built of several series of fins, simulating a spatially unlimited multi-cell structure. Two main flow structures were observed—a flow separation from the leading edge of each fin, which due to the influence of neighboring fins, was reattached to the fin, creating a closed separation zone, and a vortex, that filled that closed separation zone.
The Mass Flow Rate (hereafter referred to as MFR) through the conduit (or conduits), the internal pressure drop that is developed within the conduit and the out-coming fluid velocity that define the momentum of the injected fluid as well as the aerodynamically induced force characteristics, are governed by the dynamic laws of fluid flows. Practically speaking, the characteristics of the aerodynamically induced force depend substantially on the fluid characteristics, its dynamic behavior due to the applied driving pressure, on one hand, and on the other hand on the internal geometry of the special conduit of the present invention.
In Israeli Patent Application titled SELF ADAPTIVE SEGMENTED ORIFICE DEVICE AND METHOD (hereafter referred to as SASO), simultaneously filed with the present invention, and incorporated herein by reference, a novel flow control device is disclosed. A typical embodiment of a SASO-device comprises a fluid conduit, having an inlet and outlet, said conduit provided with a plurality of fins mounted on the internal wall of said conduit, said fins arranged in two arrays substantially opposing each other, wherein each of the fins of either one of said fin arrays, excluding the fin nearest to the inlet and the fin nearest to the outlet of said conduit, is positioned opposite one of a plurality of cavities, each cavity defined between two consecutive fins of the other substantially opposite array of fins, and a portion of said internal wall, wherein when a fluid flows through said device a plurality of vortices are formed, each vortex positioned in one of said cavities, said vortices existing at least temporarily during said fluid flow through said device, and a thin core-flow is generated between the two opposite arrays of vortices. The unique advantages of SASO-technology are that it effectively decreases MFR through the SASO-conduit, and most importantly, with respect to fluid injection aimed at generating aerodynamically induced forces, it significantly increases the internal pressure drop within the conduit (hereafter referred to as &Dgr;P), in comparison with conventional conduits with about the same lateral diameter.
It is the object of the present invention to incorporate SASO-technol
Levin Daniel
Yassour Yuvai
Brinson Patrick
Core Flow Ltd.
Reed Smith LLP
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