Fluid-carrying duct element and a sleeve section for placing around said element

Abstract: Fluid-carrying duct element having, at its outside in its longitudinal direction, delimiting members (8,15) facing one another at a distance, for generating a flow resistance in the longitudinal direction of the duct element, having, in that space in between, a mouth (9) for connection inwards in the duct element and one or more resistance elements (16) with a space in between in a direction transverse to the longitudinal direction of the duct element, set up for generating a flow resistance in a direction transverse to the longitudinal direction of the duct element and in cooperation, so as to control the fluid flow, with one of the delimiting members.

Description: The invention relates to conducting a fluid flow along the outside of a fluid-carrying duct element, for example the combustion air supply of a flue gas discharge of a combustion chamber. In particular, but not exclusively, the invention relates to flues projecting beyond a building, which flues may be directed vertically, horizontally or at any angle in between. A specific example of such flues are the combustion air supply pipes and flue gas discharge pipes which, with a space in between, run essentially concentrically and whose orifices opening into the environment (the air intake orifice and the combustion gas discharge orifice, respectively) open into the environment at a considerable distance from one another. A fluid carrying duct element according to the preamble of claim 1 is disclosed in EP-A-0.654.638. This publication shows a supply hood arranged over the mouth of the combustion air supply pipe. This hood defines a supply channel to said mouth, which supply channel has a downwardly facing inlet opening. On the outside of the supply pipe there are provided two head up rings, one of which is arranged at a distance below the inlet opening of the hood. Inside the hood there is provided a number of radial plate-like spacers distributed in circumferential direction. These spacers carry the hood, and will probably have a guiding effect on air supply to the supply pipe via the hood. Further, FR-A-2.546.612 discloses a fluid-carrying duct element carrying a supply hood arranged over the mouth of the combustion air supply pipe which hood defines a supply channel to said mouth. The inlet opening of the supply channel is defined between the underside of the hood and a flange slanting in downward direction from the mouth of the combustion air supply pipe. In the hood are arranged vertical partitions, extending from inside the hood up to the slanting flange. The object of the invention is to improve the control of a fluid flow along the outside of the duct element, in particular with an eye to improved control of the flow conditions within the duct element, such as the uniformity of the fluid flow velocity or the level of the fluid pressure. To this end, the present invention presents a fluid-carrying duct element in accordance with the combination of measures summarized in the appended Claim 1 as well as a sleeve section according to claim 13 or 16. Due to the cooperation of the delimiting members and the resistance elements, the fluid flow at the outside of the duct element encounters a flow resistance so that it can be directed into a direction suitable for the intended effect. It will be obvious to those skilled in the art how the delimiting members and the resistance elements have to be designed in order to achieve a flow resistance in the direction essentially parallel to the fluid-carrying duct element and essentially in the circumferential direction of said fluid-carrying duct element, respectively. For example, the delimiting member is designed, to that end, as a projecting circumferential flange, whereas the resistance elements are protrusions designed to be spaced from one another around the circumference of the duct element, a principal plane of said protrusions forming an angle with the direction transverse to the longitudinal direction of the duct element. It was found that the greatest control effect by means of the invention is achieved if the delimiting members and resistance elements are used in conjunction with a shell section having an end baffle being arranged loosely around the duct element and around the mouth for connection to the inside of the duct element, so that the shell section with end baffle, preferably positioned essentially concentrically around the duct element, forms a preferably annular feeder duct towards said mouth (i.e. the inflow mouth of the duct element), and which opens in the direction of, and at a distance from, the resistance elements. Such a shell section with end baffle is, in the context of flues, sometimes referred to as ventilation bowl, which in that context cooperates with the duct for supplying combustion air to a furnace. Preferably, the resistance elements and delimiting members, at least one of the delimiting members, are designed as components which are separate from the fluid-carrying duct element, so that they can be kept in stock as separate components and it is also possible for their position with respect to the mouth for inward connection in the duct element to be adjustable. A cowl is positioned around and over the mouth of the duct element so as to form a feeder duct towards said mouth, the inlet of the feeder duct being delimited by the cowl and the duct element and opening towards the delimiting member which is situated outside the cowl, preferably at a distance from the inlet, and the resistance elements being positioned around the duct element, outside the cowl, at that side of the delimiting member which faces the inlet, and at a distance from the inlet. As a result of the resistance elements outside the cowl, which may be a cowl known per se, an additional thrust effect inside the cowl and the duct element is accomplished, the throughput of fluid through the duct element consequently being improved. Surprisingly it proved possible thus to improve the throughput delivery of known, relatively ineffective cowls. It is therefore possible, by fitting a relat vely simple and inexpensive additional component on the duct element, at a lower position than the cowl fitted thereon, to improve the supply of combustion air to a furnace without having to make fundamental changes to the system as a whole. The invention is hereinafter explained in more detail on the basis of an illustrative embodiment with reference to the accompanying drawing, in which: Figure 1 schematically shows a side view of a flue having concentric tubes, constructed according to the invention; Figure 2 shows a perspective side view of the topmost section of the flue shown in Figure 1; and Figure 3 shows a view corresponding to Figure 2 of a section of an alternative embodiment. Figure 1 shows a flue 1 according to the invention. This comprises two tubes 2, 3, fitted concentrically inside one another and at a distance from one another. The inner tube 2 is designed to be connected to the flue gas discharge of an otherwise essentially closed combustion chamber, for example of a hot-water supply or a central heating facility for domestic application, said combustion chamber optionally being situated inside a building. The tube 3 is suitable for connection to the combustion air supply of such a furnace. To this end, the lower end, in the drawing, of the tube 3 may be connected in a conventional manner, via a branchpipe part of known design, to the air supply orifice of said furnace. As indicated at 4, the flue 1 is provided with a circumferential recess, running all the way round, in a pipe 3 section thickened for insulation purposes, to achieve an essentially airtight penetration through the roof 5 of a building. The tube 3 ends within a ventilation cowl 6 (sometimes referred to as ventilation bowl), whereas the tube 2 continues past said ventilation cowl 6, so that the respective mouths of the tubes 2 and 3 open into the environment, outside the building, at a distance from one another, seen in the longitudinal direction of the flue 1. As can be seen more clearly from Figure 2, the ventilation bowl 6 comprises a loosely fitting shell 7 which surrounds the tube 3 at a distance and essentially concentrically and, at its end facing away from the mouth 9 of the tube 3, carries an end baffle 8 via which the ventilation bowl 6 is fastened to the tube 2. The cowl 6 forms a feeder duct towards the (inflow) mouth 9 of the tube 3. The latter's inlet 20 situated on the underside of the cowl 6 is delimited by the cowl 6 and the tube 3. As depicted, the shell section 7 is of conical shape. Other suitable shapes are also conceivable, however. The end baffle 8 can further be formed by a continuation of the preferably conical design of the shell section or may exhibit a different shape, tapering towards the tube 2. The shell section 7 and/or the end baffle 8 may carry further ventilation facilities such as orifices, so that a gas flow from the environment towards the mouth 9 (said mouth 9 forming the inflow mouth of the so-called duct element, in this case the tube 3) is not exclusively restricted to the area at the end of the shell section 7, facing away from the end baffle 8. That end 10 of the tube 2 which opens into the environment carries a cowl 11, provided with a condensate drain, a leakage ring 12 and a condensate collecting bowl 13 by means of which condensate is passed back into the tube 2. As it happens, the design of the end 10 is not essential for the invention; other designs are likewise conceivable. At a distance below the ventilation bowl 6 there are, at the outside of the pipe 3, features 14 for the purpose of directing the fluid flow along the outside of the tube 3. What is shown is a flange 15, which projects essentially radially from the tube 3 and, at the side of said flange which faces the mouth 9 of the tube 3, a series of lips 16 which have spaces in between and which project in a ring-shaped pattern from the circumference of the tube 3. The principal surface of the lips 16 is directed essentially perpendicularly to the principal surface of the flange 15. Other angles between the principal surfaces of the lips 16 and the flange 15 are, however, likewise conceivable. It will be obvious to those skilled in the art how the flange 15 and the lips 16 should be designed to achieve a flow resistance in the longitudinal direction and the circumferential direction, respectively, of the tube 3. As shown, the lips 16 are punched from a ring 17 which is designed, integrally with the flange 15, as a separate component 14. Instead of being rectangular, the shape of the lips may also take any other conceivable form, such as rounded or, for example, tapering to a point. The principal surfaces of the lips 16 and the flange 15 may be planar, but may also, for example, be corrugated, fluted or nonplanar in some other way, for example so as to exert an additional flow resistance on the fluid flow. The features 14 may be made of any suitable material such as metal or plastic. The elements 14 have a beneficial effect on the flow behaviour along the outside of the tube 3. The ventilation bowl 6, especially its baffle 8, forms also a delimiting member, so that there are two delimiting members with the resistance elements and the mouth in between them. Figure 3 shows a variation on the elements 14 giving rise to a flow resistance. The lips 16 have now been replaced by dish elements which have arisen from a pleated collar which is fitted around the tube 13. Both the flange 15 and the baffle elements or lips 16 may be provided with, for example, further profiling or alternatively orifices for further control of the fluid flow. By means of, for example, orifices in the flange 15 and/or the baffle elements 16 it is possible to allow a portion of a fluid flow to pass said elements 15 and/or 16. The invention is based on the insight that by means of the cooperation of elements, which cause a flow resistance or an obstacle to a flow in the longitudinal direction of the duct element respectively in the circumferential direction, the fluid flow outside the duct element can be controlled in the direction to the mouth. This is advantageous, in particular, in the case of, for example, flues which are subject to varying wind directions, so that the prevailing wind direction and wind speed has a verifiable effect on, for example the behaviour of the fluid flow and, for example, the pressure within the duct element. The abovementioned effect can be achieved very simply by positioning, below the air inlet cowl at some distance from its inflow orifice situated underneath, a ring which fits around the duct element, extends transversely to the duct element and, at its top side facing the inflow orifice, is provided with baffles which essentially extend vertically. The invention therefore also relates to an annular disc for fitting on/around a duct element, the annular disc at one of its sides being provided with baffles which essentially extend transversely with respect to the disc.

Claims: Fluid-carrying duct element (3) having: at a mouth (9) at its outside a ventilation bowl (6), which is arranged concentrically loosely around the duct element (3) and over the mouth (9) of the duct element (3) so as to form a feeder duct towards said mouth (9) of the duct element (3), said feeder duct having a downwardly opening inlet (20); one or more resistance elements (16) for generating a flow resistance or obstacle to the flow in a circumferential direction around the duct element (3) transverse to the longitudinal direction of the duct element (3), said resistance elements being arranged outside the duct element (3) interspaced from one another around the circumference of the duct element; and on the outside of the duct element (3), at least one delimiting member (15) for generating a flow resistance or obstacle to the flow in a longitudinal direction of the duct element (3), said delimiting member being arranged outside the ventilation bowl (6) at a distance from the downwardly opening inlet (20) of the feeder duct; characterized in that the resistance elements (16) are positioned at that side of the delimiting member (15) which faces the downwardly opening inlet (20), at the outside of the ventilation bowl (6) and feeder duct, and at a distance from the downwardly opening inlet (20), such that the resistance elements (16) and the delimiting member (15) can in cooperation direct the fluid flow along the outside of the duct element (3) in the direction to the downwardly opening inlet (20). Fluid carrying duct element according to claim 1, characterized in that the resistance elements comprise protrusions (16), such as lips, projecting from the circumference of the duct element (3) and having principal planes which are at an angle with respect to a transverse plane perpendicular to the longitudinal direction of the duct element (3). Fluid carrying duct element according to claim 2, characterized in that the vertical axes of the principal planes of the protrusions (16) are directed essentially parallel to the longitudinal direction of the duct element (3). Fluid carrying duct element according to one of the preceding claims, characterized in that the at least one delimiting member comprises a flange (15), discontinuous or continuous, which essentially runs around the fluid-carrying duct element and projects from its circumference, preferable essentially radially. Fluid carrying duct element according to one of the preceding claims, characterized in that the delimiting member comprises a flange (15), which essentially runs around the fluid carrying duct element and which is designed integrally with a ring (17) contiguous to the inner contour of the flange, and that the resistance elements comprise lips punched from the ring and bent outwardly. Fluid carrying duct element according to one of the claims 1-4, characterized in that the resistance element comprises a pleated collar, which is fitted around the duct element and has a plurality of baffle elements (16) generating a flow resistance in the circumferential direction. Fluid carrying duct element according to one of the preceding claims, characterized in that the resistance elements (16) are arranged in cooperation, so as to control the fluid flow, with the ventilation bowl. Fluid carrying duct element according to one of the preceding claims, characterized in that the feeder duct is annular. Fluid carrying duct element according to one of the preceding claims, characterized in that the fluid carrying duct element is a combustion air supply duct to a, preferably otherwise essentially closed, combustion chamber. Fluid carrying duct element according to one of the preceding claims, characterized in that the duct element is one of two duct elements essentially concentrically surrounding one another with a space in between; the one, preferably the outermost one, forming a combustion air supply to a, preferably otherwise essentially closed, combustion chamber, and the other forming a flue gas discharge of the combustion chamber. Fluid carrying duct element according to one of the preceding claims, characterized in that one of the delimiting members and the adjoining resistance element cooperating therewith are designed as a separate component, which is separate from the duct element, and in which the delimiting member and the adjoining resistance member preferably form part of a separate sleeve section (14) which surrounds the duct element. Fluid carrying duct element according claim 11, characterized in that the separate component (14) is a separate sleeve section surrounding the duct element (3) in which the sleeve section comprises: a ring (17) having an internal profile essentially matching the outer periphery of the fluid carrying duct element (3), a, continuous or discontinuous, flange (15) defining the delimiting member, and running essentially in circumferential direction of the ring (17), protrusions (16) defining the resistance elements, which protrusions are lip-shaped or have some other shape, in which the flange (15) and protrusions (16) both project beyond the circumference of the ring (17), and in which the principal planes of the protrusions (16) form angles with the plane in which the flange (15) is situated. Fluid carrying duct element according to claim 11 or 12, characterized in that the position of said delimiting member and said adjoining resistance element is adjustable with respect to the mouth (9). Sleeve section (14) suitable for being placed around a fluid carrying duct element (3), at a distance from the downwardly opening inlet (20) of a ventilation bowl (6), which is arranged concentrically around the duct element (3) and over a mouth (9) of the duct element (3) so as to form a feeder duct towards said mouth (9) of the duct element, characterized in that the sleeve section (14) comprises: a ring (17) having an internal profile essentially matching the outer periphery of the fluid carrying duct element (3), a, continuous or discontinuous, flange (15) running essentially in circumferential direction of the ring (17) for generating a flow resistance or obstacle to the flow in a longitudinal direction of the duct element, protrusions (16) for generating a flow resistance or obstacle to the flow in a circumferential direction around the duct element (3) transverse to the longitudinal direction of the duct element (3) in which the protrusions are lip-shaped or have some other shape and have principal planes forming an angle with the plane in which the flange is situated, and in which the flange (15) and protrusions (16) both project beyond the circumference of the ring (17), such that the protrusions (16) and the flange (15) can in cooperation direct the fluid flow along the outside of the duct element (3) in the direction to the inlet (20) of the bowl. Sleeve section according to claim 14, characterized in that the principal plane of the protrusions (16) is at an angle perpendicular to the plane of the flange. Sleeve section according to claim 14 or 15, characterized in that the protrusions (16) are lips punched from the ring (17) and bent outwardly. Sleeve section suitable for being placed around a fluid carrying duct element at a distance from the downwardly opening inlet (20) of a ventilation bowl (6), which is arranged concentrically around the duct element (3) and over a mouth (9) of the duct element (3) so as to form a feeder duct towards said mouth (9) of the duct element (3), characterized in that the sleeve section comprises a collar pleated around an inner profile, such that the pleats form a plurality of baffle elements for generating a flow resistance or obstacle to the flow in a circumferential direction around the duct element (3) transverse to the longitudinal direction of the duct element (3), in which the inner profile of the collar essentially matches the outer periphery of the fluid carrying duct element, and that the sleeve section is provided with an annular disc (15) projecting transversely from the inner profile to the outer periphery of the collar for generating a flow resistance or obstacle to the flow in a longitudinal direction of the duct element, in which the baffle elements and disc can in cooperation direct the fluid flow along the outside of the duct element (3) in the direction to the inlet (20) of the bowl (6).

Inventors: PESTOOR IETSE JAN, PESTOOR, IETSE JAN
Applicants: MUELINK & GROL BV, MUELINK & GROL B.V.
Application year: 1996
Main classification: F23L17
IPC codes: F23L17, F23J13