SHIELDING DEVICE

Abstract: The invention relates to a shielding device which is intended to be placed onto the end of a gas-discharge pipe of a heating appliance and which has the purpose of shielding the gas-discharge pipe from rain and wind. To this end, the shielding device comprises a covering member which extends at a distance over a gas-conducting pipe (20). A shielding pipe (10) is arranged coaxially with the gas-conducting pipe (20), between the covering member and the gas-conducting pipe (20). A water-discharge opening (23) is defined between the gas-conducting pipe (20) and the shielding pipe (10). The shielding device further comprises a water-discharge member (30) which is situated between the gas-conducting pipe (20) and the gas-discharge pipe. An annular water-discharge opening (40) is defined between the gas-conducting pipe (20) and the water-discharge member (30). A covering cap (50) extends over the annular opening (40).

Description: SHIELDING DEVICE The present invention relates to a shielding device, comprising a shielding pipe with a shielding-pipe top end and a shielding-pipe bottom end; a covering member which extends over the shielding-pipe top end; at least one gas-outlet opening at the shielding-pipe top end; a gas-conducting pipe which is arranged coaxially with the shielding pipe at the shielding-pipe bottom end and has a gas-conducting pipe top end and a gas- conducting pipe bottom end, the diameter of the said gas- conducting pipe being smaller than the diameter of the shielding pipe; at least one water-discharge opening at the shielding-pipe bottom end, between the shielding pipe and the gas-conducting pipe; and an annular water-discharge member which is arranged coaxially with the gas-conducting pipe at the gas-conducting pipe bottom end and which has a water-discharge top end and a water-discharge bottom end. Such shielding devices are known in practice and are intended, for example, to be placed onto the end of a gas- discharge pipe of a heating appliance such as a high-efficiency boiler, improved-efficiency boiler or the like. As is known, gas-fired heating appliances have a discharge pipe for discharging flue gas. Such a gas-discharge pipe is usually vertically oriented, but may also be oriented horizontally or inclined upwards. The gas-discharge pipe leads from the heating appliance, which is arranged inside, for example, a house, through a wall or a roof of the house in question, to the outside in order to discharge the flue gases to the outside. One problem which may arise is that rainwater enters the end of the gas-discharge pipe and may flow into the interior of the house and/or the heating appliance, which is undesirable. To counteract this problem, shielding devices which are intended to be placed onto the end of a gas-discharge pipe with the aim of counteracting the penetration of rain have been developed. A further task of these shielding devices is to stop the flue gases which flow out of the gas-discharge pipe from returning to the heating appliance via an air-supply pipe. In this context, an important design requirement is that a shielding device must only present a minor obstacle to the outflow of flue gases. To this end, a shielding device primarily comprises a gas- conducting pipe and a covering member. The gas-conducting pipe has approximately the same shape as the gas-discharge pipe for which it is intended; since such gas-discharge pipes are usually circular, the gas-conducting pipe usually also has approximately the form of a circular cylinder. The diameter of the gas- conducting pipe is generally approximately equal to that of the gas-discharge pipe. When the shielding device has been fitted, the gas-conducting pipe is situated substantially in line with the gas-discharge pipe. The covering member extends over the free end of the gas-conducting pipe, directed away from the gas- discharge pipe. The covering member usually has the form of a flat or conical plate with a diameter which is greater than that of the gas-conducting pipe. Obviously, the shielding device has an outlet opening through which flue gas can leave the gas-conducting pipe. To this end, the covering member is held at a suitable distance from the free end of the gas-conducting pipe. The said components would be adequate to counteract the penetration of rain given a vertical orientation of the gas- conducting pipe provided there is no wind. However, owing to wind, rainwater may be blown under the covering member and reach the end of the gas-conducting pipe. To stop this, the shielding device is provided with a shielding pipe with a diameter which is greater than that of the gas-conducting pipe, which shielding pipe is arranged coaxially with the gas-conducting pipe, in line with the latter, between the gas-conducting pipe and the covering member. The shielding pipe has a bottom end or gas- entry end which has a certain axial overlap with the free top end of the gas-conducting pipe. The covering member extends over the top end of the shielding pipe, has a diameter which is greater than that of the shielding pipe, and is situated at a certain axial distance from the top end of the shielding pipe in order to define the outlet opening of the shielding device. If rainwater is now blown under the covering member by wind, most of the rain will be kept away from the top end of the gas-conducting pipe by the shielding pipe. Rain that is blown onto the outer surface of the shielding pipe flows downwards along the said outer surface and drops off freely, outside the gas-conducting pipe. Rain that is blown through the gas outlet opening between the covering member and the top end of the shielding pipe will partly reach the inner surface of the shielding pipe. This water flows downwards along the said inner surface and likewise drops off freely, outside the gas- conducting pipe, through at least one water-discharge opening which is defined between the bottom end of the shielding pipe and the top end of the gas-conducting pipe since the internal diameter of the shielding pipe is greater than the external diameter of the gas-conducting pipe. Although the known shielding device is in practice quite adequate, it can nevertheless happen that in practice rainwater does reach the interior of the gas-conducting pipe. This can happen, on the one hand, because some of the rain which is blown through the gas outlet opening between the covering member and the top end of the shielding pipe has a falling trajectory such that it reaches the interior of the gas-conducting pipe. On the other hand, it may in practice happen that the wind pressure is such that rainwater is blown inwards through the said water- discharge opening, over the edge of the gas-conducting pipe, and thus reaches the interior of the gas-conducting pipe. Therefore, one object of the present invention is to improve the known shielding device further. More particularly, the present invention aims to provide an improved shielding device in which the said problem is eliminated or at least reduced. In principle, it would be possible to shield the water- discharge opening adequately against wind, so that no wind and therefore no rainwater can enter through the said water- discharge opening. However, it has been found that a flow of air inwards through the water-discharge opening has a beneficial effect on the flow of air in the interior of the shielding pipe and contributes to the effect whereby the rainwater which is blown inwards through the gas outlet opening between the covering member and the shielding pipe is as far as possible kept away from the top end of the gas-conducting pipe. Consequently, the overall characteristics of the shielding device would be impaired if the water-discharge opening were to be shielded against wind. In the known shielding device, the gas-conducting pipe directly adjoins a gas-discharge pipe. Consequently, water which reaches the interior of the gas-conducting pipe will also in fact reach the interior of the gas-discharge pipe. According to an important aspect of the present invention, the gas-conducting pipe is held at a distance from the end of the gas-discharge pipe, and means are provided for discharging water which flows down along the inner surface of the gas-conducting pipe to the outside before this water reaches the gas-discharge pipe. According to the present invention, a shielding device of the above-mentioned type is characterized in that the water- discharge member comprises a substantially axial inner ring, the diameter of the water-discharge top end being smaller than the diameter of the gas-conducting pipe bottom end and also being smaller than the diameter of the water-discharge bottom end; in that an annular opening is situated between the gas-conducting pipe and the water-discharge member; and in that an annular covering cap extends in the axial direction over the outer circumference of the said annular opening. These and other aspects, characteristics and advantages of the present invention will be explained in more detail by the following description of a number of preferred embodiments of a shielding device according to the invention, with reference to the drawing, in which identical reference numerals denote identical or similar components, and in which: figure 1 is a cross section, in the axial direction, through a known shielding device, figure 2 is a cross section, in the axial direction, through part of a shielding device according to a first preferred embodiment of the invention, figure 3 is a cross section, in the axial direction, through part of a shielding device according to a second preferred embodiment of the invention, figure 4 is a cross section, in the axial direction, through part of a shielding device according to a third preferred embodiment of the invention. Figure 1 shows a shielding device known in practice, denoted in general by the reference numeral 1, in an orientation corresponding to the operating position. The shielding device 1 comprises a round shielding pipe 10 with a shielding-pipe top end 11 and a shielding-pipe bottom end 12. At the shielding-pipe top end 11, the shielding pipe 10 has an annular covering-member support 9, intended for fixing thereto a cap-like covering member (not shown in the figure for the sake of simplicity) having a diameter which is greater than the diameter of the shielding pipe 10 and, in the fitted position, extending over the shielding-pipe top end 11. Four gas-outlet openings 13 are formed between the covering-member support 9 and the shielding pipe 10, by the fact that the covering-member support 9 is fixed at a distance from the shielding pipe 10 by means of four supports 14. On the side of the shielding-pipe bottom end 12, a gas- conducting pipe 20 is arranged coaxially with the shielding pipe 10. The diameter of the gas-conducting pipe 20 is smaller than the diameter of the shielding pipe 10. The gas-conducting pipe 20 has a gas-conducting pipe top end 21 and a gas-conducting pipe bottom end 22. The gas-conducting pipe top end 21 overlaps in axial direction with the shielding-pipe bottom end 12. By means of the shielding-pipe bottom end 12, the shielding pipe 10 is attached to the outer surface of the gas-conducting pipe 20 by means of four shielding-pipe supports 24 which are distributed uniformly over the circumference of the outer surface of the gas-conducting pipe 20, with the result that four water-discharge openings 23 are formed between the shielding pipe 10 and the gas-conducting pipe 20. For the known shielding device 1 illustrated, a shielding-pipe support 24 is designed as a bent strip with a substantially radial short end 25 and an inclined section 26. The shielding-pipe supports 24 are attached to the gas-conducting pipe 20 by means of the short end 25 and to the shielding-pipe bottom end 12 by means of the inclined section 26. An axially oriented opening (not shown) is arranged in the short end 25 of each shielding-pipe support 24, through which opening, by way of example, a screw (not shown) or a dowel can be fitted. The known shielding device 1 further comprises an annular water-discharge member 30 with a water-discharge top end 31 and a water-discharge bottom end 32. The water-discharge member 30 comprises an outer ring 34 which is arranged coaxially with the gas-conducting pipe 20. The diameter of the outer ring 34 is greater than the diameter of the gas-conducting pipe 20. At its top end, the outer ring 34 is connected to the gas-conducting pipe 20 by a radial, annular flange 35. The water-discharge member 30 is attached to the short end 25 of the shielding-pipe supports 24 by means of the flange 35. The gas-conducting pipe 20 is designed in two parts 20a, 20b, the top gas-conducting pipe part 20a being designed as a single integral unit with the shielding pipe 10 and the bottom gas-conducting pipe part 20b being designed as a single integral unit with the water-discharge member 30. The bottom gas- conducting pipe part 20b adjoins sealingly the top gas- conducting pipe part 20a, so that the bottom gas-conducting pipe part 20b extends the top gas-conducting pipe part 20a from its bottom end. Three attachment supports 36 are provided transversely to the flange 35, between the gas-conducting pipe 20 and the outer ring 34. An opening is formed in the radial direction in each attachment support 36, through which opening, by way of example, a screw can be fitted in order to attach the shielding device 1 to a gas-discharge pipe. A top end of such a gas-discharge pipe is then positioned between the outer surface of the bottom gas- discharge pipe part 20b and the attachment supports 36. Three openings 37, which are aligned with the openings in the attachment supports 36, are formed in the outer ring 34. A screwdriver, for example, can be put through the openings 37 in the outer ring 34 in order to tighten screws which are arranged in the openings in the attachment supports 36. For the now following description of the way in which the known shielding device 1 operates, it is assumed that the gas- discharge pipe (not shown) to which the shielding device 1 is attached is arranged vertically and that the shielding device 1 is consequently also in a vertical position, with the water- discharge member 30 at the bottom and the covering member at the top, as shown in figure 1. Rainwater which falls onto the covering member or onto the outer surface of the shielding pipe 10 or the gas-conducting pipe 20 is discharged on the outside of the shielding device 1 under the force of gravity. The same applies to any condensation water. Rainwater which penetrates in through a gas outlet opening 13 is discharged in the interior of the shielding device 1. This water flows downwards along the inner surface of the shielding pipe 10 and flows via a shielding-pipe support 24 or drops through a water-discharge opening 23 on to the flange 35 of the water-discharge member 30, or falls from the shielding pipe 10 directly through a water-discharge opening 23 on to the flange 35 of the water-discharge member 30. Then, the water is discharged along the outer surface of the water-discharge member 30. However, rainwater which falls directly into the gas- conducting pipe 20 or is conveyed upwards by wind pressure on the gas-conducting pipe top end 21 and thus reaches the inner surface of the gas-conducting pipe 20 cannot be discharged outwards by this known shielding device 1 and enters the gas- discharge pipe, which is undesirable. Figure 2 shows a shielding device 2 according to a first preferred embodiment of the invention, wherein a solution to the above-described drawback is provided. In figure 2, the shielding pipe 10 and the gas-conducting pipe 20 can be recognized, as well as the gas outlet openings 13, the supports 14, the water- discharge openings 23 and the shielding-pipe supports 24. The shape and function of these components may be identical to those of the identical or similar components of the known shielding device 1 which is shown in Figure 1 and require no further explanation. In the embodiment of the shielding device 2 shown, the water-discharge member 30 comprises an inner ring 33 which is arranged coaxially with the gas-conducting pipe 20. The diameter of the top end of the inner ring 33 is smaller than the diameter of the gas-conducting pipe bottom end 22. In the preferred embodiment shown, there is a slight amount of axial overlap between the water-discharge top end 31 and the gas-conducting pipe bottom end 22, although this is not essential. An annular opening 40 is situated in the radial direction between the water-discharge top end 31 and the gas-conducting pipe bottom end 22, which opening is large enough to allow drops of water to pass through. Four connecting supports 38 are distributed uniformly over the circumference of the flange 35. Only one connecting support 38 is shown in Figure 2. The connection supports 38 are located on the top surface of the flange 35 and in the axial direction extend to beyond the inner ring 33. In the fitted position, the connecting supports 38 extend in the axial direction to the short end 25 of the shielding-pipe supports 24, wherein a connecting member such as for example a screw or a dowel which has been fitted through the said axially oriented opening in the short end 25 of a shielding-pipe support 24 is fixed in a connecting support 38. Shielding device 2 further comprises an annular covering cap 50, a top end of which substantially sealingly adjoins the outer surface of the gas-conducting pipe 20 and a bottom end of which adjoins the top surface of the flange 35. In the embodiment shown, the covering cap 50 comprises a substantially radial top ring 51 with an internal diameter which is substantially equal to the external diameter of the gas- conducting pipe 20, a substantially axial cap ring 53 with an internal diameter which is greater than the external diameter of the top ring 51, and an inclined ring 54 which is arranged between the top ring 51 and the cap ring 53. Three openings 55, which are distributed evenly over the circumference of the cap ring 53, are arranged at the bottom end of the cap ring 53. If desired, a raised edge 52 may be arranged on the inner circumference of the top ring 51, and a hook-like gas-conducting pipe edge 28, which encloses the said raised edge 52, may be arranged on the outer surface of the gas-conducting pipe 20. In the fitted position, the top ring 51 is advantageously attached to the short end 25 of the shielding-pipe supports 24 by means of the connecting supports 38. To this end, four openings, which are distributed uniformly over the circumference of the top ring 51, are arranged in the top ring 51 in the axial direction. In the fitted position, these openings are aligned with the openings which are formed in the short end 25 of the shielding- pipe supports 24, and the top ring 51 is positioned in the axial direction between the short end 25 of the shielding-pipe supports 24 and the connecting supports 38. The discussed embodiment of the shielding device 2 comprises four shielding-pipe supports 24 and therefore four water-discharge openings 23, but may also comprise more or fewer shielding-pipe supports 24 and water-discharge openings 23. Condition is that the shielding device 2 comprises at least one water-discharge opening 23. In this first preferred embodiment of the invention, three openings 55 are formed at the bottom end of the cap ring 53, but there could also be more or fewer such openings. Condition is that there is at least one opening 55 arranged at the bottom end of the cap ring 53. The discussed embodiment of the shielding device 2 comprises four connecting supports 38, but may also comprise more or fewer connecting supports 38. Preferably, the shielding device 2 comprises at least two connecting supports 38. For the now following description of the way in which a shielding device 2 according to the invention functions, it is assumed that the shielding device 2 is arranged in a vertical position. Rainwater which falls onto the covering member or against the outer surface of the shielding pipe 10 or the gas-conducting pipe 20 and water which is situated on the inner surface of the shielding pipe 10 is discharged in the same way as that which has already been described above in relation to the known shielding device 1. Rainwater which penetrates through a gas outlet opening 13 and reaches the inner surface of the gas-conducting pipe 20 or which is conveyed upwards by the wind pressure onto the gas- conducting pipe top end 21 and thus reaches the inner surface of the gas-conducting pipe 20 is discharged into the interior of the shielding device 2. This water flows downwards along the inner surface of the gas-conducting pipe 20 and, at the gas- conducting pipe bottom end 22, drops through the annular opening 40 from the gas-conducting pipe 20 onto the water-discharge member 30. Then, the water is discharged along the top surface of the flange 35 of the water-discharge member 30, through an opening 55 in the cap ring 53, to the outer side of the shielding device 2. The top surface of the flange 35 is advantageously of inclined design, with a smaller diameter at the top end than at the bottom end, so that the water can be discharged readily along the top surface of the flange 35 under the force of gravity. The covering cap 50 prevents rain from being deposited on a section of the water-discharge member 30 and on a section of the outer surface of the gas-conducting pipe 20. The covering cap 50 serves primarily to prevent water from being blown from the water-discharge member 30 into the gas-discharge pipe via the annular opening 40 by the wind. The openings 55 in the cap ring 53 should not be too large, in order to let the influence of factors such as wind and water on the outside on the discharge of water and the outflow of flue gases from the shielding device 2 be as small as possible. However, they must be large enough to allow the water which is to be discharged to pass through. Preferably, an obstruction is arranged between the openings 55 and the annular opening 40, so that the influence of the wind on the discharge of water and the outflow of flue gases from the shielding device 2 is reduced further. This obstruction may advantageously be formed by the connecting supports 38 if these supports are aligned with the openings 55. Figure 3 illustrates a detail of a second preferred embodiment of a shielding device 3 according to the invention, in which the covering cap 50 is designed in two parts 50a, 50b. The top covering-cap part 50a is designed as a single integral unit with the gas-conducting pipe 20. The bottom covering-cap part 50b is designed as a single integral unit with the water- discharge member 30. The gas-conducting pipe 20 may form a single integral unit with the shielding pipe 10, as shown in figure 2, or with the covering cap 50, as shown in figure 3. Obviously, the gas- conducting pipe 20 may also form a single integral unit with the shielding pipe 10 and the covering cap 50. Figure 4 illustrates a detail of a third preferred embodiment of a shielding device 4 according to the invention, in which the gas-conducting pipe 20 is designed in two parts 20a, 20b. The top gas-conducting pipe part 20a is designed as a single integral unit with the shielding pipe 10. The bottom gas- conducting pipe part 20b is designed as a single integral unit with the covering cap 50. Furthermore, the shielding device 4 comprises three cap connecting supports 56, which are arranged on the top ring 51 of the covering cap 50 and, in the axial direction, overlap the cap ring 53 and the inclined ring 54. Openings which are aligned with openings in the radial direction which are formed in the connecting support s 38 are formed in the radial direction in the cap connecting support s 56. The covering cap 50 and the water discharge 30 can be fitted together by arranging connecting members, such as for example screws or rivets, in the openings. In turn, the covering cap 50 is attached to the shielding pipe 10 at the short end 25 of the shielding pipe supports 24. It will be clear to the person skilled in the art that the scope of the present invention is not limited to the examples which have been discussed in the foregoing, but rather numerous alterations and modifications to these examples are possible without departing from the scope of the invention as defined in the appended claims. For example, the modifications which have been discussed with reference to Figures 3 and 4 may be combined with one another in any desired way. Furthermore, the transverse contour, which for the various components of the present invention has been described as circular, may also, for example, be square or of any other shape. The term "annular" is deemed to encompass all these contour shapes.

Claims: * * CLAIMS ** 1. Shielding device, comprising: a shielding pipe with a shielding-pipe top end and a shielding- pipe bottom end; a covering member which extends over the shielding-pipe top end; at least one gas-outlet opening at the shielding-pipe top end; a gas-conducting pipe which is arranged coaxially with the shielding pipe at the shielding-pipe bottom end and has a gas- conducting pipe top end and a gas-conducting pipe bottom end, the diameter of the said gas-conducting pipe being smaller than the diameter of the shielding pipe; at least one water-discharge opening at the shielding-pipe bottom end, between the shielding pipe and the gas-conducting pipe; and an annular water-discharge member which is arranged coaxially with the gas-conducting pipe at the gas-conducting pipe bottom end and which has a water-discharge top end and a water-discharge bottom end; characterized in that the water-discharge member (30) comprises a substantially axial inner ring (33) , the diameter of the water- discharge top end (31) being smaller than the diameter of the gas-conducting pipe bottom end (22) and also being smaller than the diameter of the water-discharge bottom end (32) ,- in that an annular opening (40) is situated between the gas- conducting pipe (20) and the water-discharge member (30) ; and in that an annular covering cap (50) extends in the axial direction over the outer circumference of the said annular opening (40) . 2. Shielding device according to claim 1, characterized in that the covering cap (50) adjoins the top surface of the water- discharge member (30) , at least one opening (55) being formed between the covering cap (50) and the water-discharge member (30) . 3. Shielding device according to claim 2, characterized in that an obstruction (38) is arranged between the openings (55) in the covering cap (50) and the annular opening (40) . 4. Shielding device according to one or more of the preceding claims, characterized in that the covering cap (50) adjoins the outer surface of the gas-conducting pipe (20) . 5. Shielding device according to one or more of the preceding claims, characterized in that the water-discharge top end (31) overlaps the gas-conducting pipe bottom end (22) in the axial direction. 6. Shielding device according to one or more of the preceding claims, in which the water-discharge member (30) comprises an inclined flange (35) , characterized in that the diameter of the inclined flange (35) increases in the direction from the water- discharge top end (31) towards the water-discharge bottom end (32) . 7. Shielding device according to one or more of the preceding claims, characterized in that the covering cap (50) comprises, on the outer surface, an inclined ring (54) , the diameter of which increases in the direction from the top end towards the bottom end. 8. Shielding device according to one or more of the preceding claims, characterized in that the gas-conducting pipe (20) in its entirety is designed as a single integral unit with the shielding pipe (10) . 9. Shielding device according to one or more of the preceding claims, characterized in that at least part of the gas- conducting pipe (20) is designed as a single integral unit with at least part of the covering cap (50) . 10. Shielding device according to one or more of the preceding claims, characterized in that at least part of the covering cap (50) is designed as a single integral unit with the water- discharge member (30) .

Inventors: NIEUWENHUIS HENDRIK JOHAN ARNO, NIEUWENHUIS, HENDRIK, JOHAN, ARNOUT
Applicants: INTERACTIVE BOUWPRODUKTEN B V, INTERACTIVE BOUWPRODUKTEN B.V.
Application year: 2000
Main classification: F23L17
IPC codes: F23L17