IE84088B1 - Flue systems - Google Patents

Description

FLUE SYSTEMS This invention relates to flue systems particularly, but not exclusively, for use with heating appliances heated by oil or gas burners, and flue systems which particularly, but not exclusively, employ the Venturi effect to at least aid in the extraction of products of combustion from the appliances.

Flue systems are known which incorporate a fan to extract the products from the appliance. In the known systems the products pass through the fan, and as they are usually hot, the fan must be capable of withstanding higher than ambient temperatures. In addition, if the burner uses oil, the products from this type of burner can be contaminated with soot and cause the fan to become blocked. This may happen quite quickly, before normal servicing of the appliance is due. Often the fans are placed in or near a flue tube attached to the appliance, which may make them difficult to install, noisier and difficult to access for maintenance.

According to a first aspect of the present invention there is provided a flue system adapted to be connected to a heating appliance to remove products of combustion therefrom, comprising a flue terminal box having at least one inlet for air and at least one outlet for air and products, a flue chamber and a fan in the flue terminal box, a flue tube adapted to be attached at a first end to the heating appliance to receive the products therefrom and at a second end remote from the heating appliance being provided with a mixing adapter which extends into the flue chamber and has a first end received by and fixed in the second end of the flue tube for the products received by the flue tube to pass through the mixing adapter and enter at a second end into the flue chamber intermediate the fan and the outlet, and the fan being arranged to blow air along the flue chamber transversely of the direction of flow of the products through the mixing adapter, to draw the products into the flue chamber from the flue tube by way of the mixing adapter, and blow the products along the flue chamber away from the fan to exit from the flue terminal box at the outlet.

By blowing transversely of the direction of flow of products through the mixing adapter in this way, a Venturi effect is set up which acts to draw the products towards and out of the second end of the flue tube away from the appliance.

Preferably the fan is arranged to blow in a direction substantially perpendicular to the direction of the flow of products through the mixing adapter.

The appliance may be oil or gas heated.

The flue tube may be substantially cylindrical in shape, and may be made of metal. The mixing adapter may also be substantially cylindrical in shape and may be made of metal. At the second end of the mixing adapter a part of the cylindrical wall of the adapter may be cut away, to form a C- shaped portion of the wall at this end. This C—shaped portion acts to direct the products leaving the mixing adapter towards the outlet.

The flue chamber is preferably substantially tubular in shape, and the second end of the mixing adapter is preferably received in an aperture in the longitudinal wall of the flue chamber and is fixed therein. Preferably the second end of the mixing adapter is received in the flue chamber such that the longitudinal axis of the mixing adapter at that end lies substantially perpendicular to the longitudinal axis of the chamber.

The flue chamber may extend vertically, horizontally, or in another attitude, as appropriate or convenient for the installation, when the flue system is installed for use with a heating appliance.

One end of the flue chamber is preferably connected to the fan to allow the fan to blow along the length of the chamber and thus across the mixing adapter. The products leave from the other end of the flue chamber.

The mixing adapter may pass through an aperture in a wall of the flue terminal box to reach the flue chamber. One part of the flue terminal box may be provided with the at least one inlet to allow air to pass into the box to the fan and the at least one outlet may be provided in the same part or another part to allow air from the fan and products from the appliance to exit from the box. The or each inlet and outlet may be provided as a grid.

The fan may have an in-built motor, or a separate motor may be provided.

Either the flue tube or the mixing adapter, or both of these, may extend, in use, through an aperture provided in an external wall of a building which houses the heating appliance, to carry the products of combustion from the appliance to the flue terminal box to pass to the surrounding environment. Preferably the flue terminal box is positioned over the aperture in the external wall to allow the mixing adapter to pass into the flue chamber.

Using a flue system as described above, the products of combustion from the heating appliance with which it is used do not pass through the fan and therefore it is not heated or contaminated by these products.

Furthermore, the products are cooled by the blowing of the fan. The fan can be provided remotely from the flue tube which makes it easier to install and maintain. A smaller size aperture may be provided in the external wall to receive the flue tube and/or mixing tube than has been necessary for known types of flue, which also makes installation of the flue system, and of the appliance with which it is used, easier.

The flue system may be adapted for use with various kinds of heating appliance, including domestic space and/or cooking appliances and boilers.

It may, for example, be adapted for use with a cooking appliance of the range type which may include a boiler.

According to a second aspect of the present invention there is provided a heating appliance connected to a flue system in accordance with the first aspect of the invention herein set forth by which products of combustion are extracted from the heating appliance.

An embodiment of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a cross—sectional View through a flue system according to the present invention; Figure 2 is a section along line II-II of Figure 1; an Figure 3 is a perspective View of part ofthe flue system.

Figure 1 shows a flue system 1 connected for use with an oil or gas heated range—type cooker or boiler (not shown). The flue systeml comprises a flue tube 2, a mixing adapter 3, a fan 4, a flue chamber 5, an outlet manifold 6 and a flue terminal box 7.

The flue tube 2 comprises an open-ended, hollow cylinder having a first end (not shown) and a second end 8. The first end is connected to the cooker to communicate with a flue duct from the oil or gas burner or burners of the cooker. The second end 8 of the flue tube 2 passes through an aperture 9 in an external wall 10 of a building which houses the cooker.

The second end 8 of the flue tube 2 lies flush with the external surface of the wall 10.

The mixing adapter3 comprises an open-ended, hollow, cylinder formed by a longitudinal wall 11 and having a first end 12 and a second end 13. The first end 12 is co-axially received and fixed within the second end 8 of the flue tube 2 and is a flush fit therein. The mixing adapter 3 extends substantially perpendicularly from the external wall 10, and is received in the flue chamber 5 and extends a substantial part ofthe way into the flue chamber 5. At the second end 13 of the mixing adapter 3 a part of the wall 11 is cut away to form a C-shaped portion 14 Figures 2 and 3.

The flue chamber 5 also comprises an open-ended, hollow tubular body 15 (in this embodiment of square cross-section but it could be of circular or other cross-section) and having a first end 16 and a second end 17. An aperture 18, Figure l, is formed in the side of the body 15, and the mixing adapter 3 is received in the aperture 18 as a flush fit and is fixed therein. The longitudinal axis of the mixing adapter3 is substantially perpendicular to the longitudinal axis of the flue chamber 5, and the C- shaped portion 14 of the second end 13 of the mixing adapter 3 lies towards the first end 16 of the flue chamber 5, as shown. The first end 16 of the flue chamber 5 is connected via a flange 19 to a body of the fan 4, and the second end 17 of the chamber 5 is connected to the outlet manifold 6. In this embodiment the outlet manifold 6 is essentially cylindrical but it may be of square or other cross-section. The outlet manifold has an open bottom end 20.

The fan 4 and the flue chamber 5 are housed in the flue terminal box 7 and are supported therein by flanges 21. The open bottom end 20 of the outlet manifold 6 opens near to the bottom of the flue terminal box which is closed. The flue terminal box 7 abuts the external wall 10, and has an aperture therein to allow the mixing adapter 3 to pass into the box 7.

The flue terminal box 7 has louvred inlets 22, Figures 1 and 2, at one side of its upper part which allows air from the surrounding environment to pass into the box 7 for use by the fan 4. Outlets 23 in the form of grids at opposite sides of the lower part of the flue terminal box 7 allow the air and the products of combustion from the burner or burners of the cooker to exit the box 7.

The burner or burners may have a thermostatic control linked in with the rate of extraction of the products of combustion from the cooker by the fan.

In use, air is drawn into the flue terminal box 7 by the fan 4 and is blown along the length of the flue chamber 5, across the second end 13 of the mixing adapter 3. This sets up a Venturi effect across this end of the adapter3 which results in the products of combustion from the cooker burner or burners being drawn from the adapter 3 and into the flue chamber 5. The C-shaped portion 14 of the mixing adapter3 and the direction of air blown from the fan4 directs the air and the products of combustion towards the second end 17 of the flue chamber 5 and the outlet manifold 6. The mixture of air and products of combustion is blown into the outlet manifold 6, and from there passes out of the flue terminal box 7 at the outlets 23 to the surrounding environment. In this way products of combustion are removed from the cooker.

The flue terminal box 7 and flue chamber 5 are shown vertically disposed in the drawings but they may instead be disposed horizontally or in other attitude if more suitable for the particular installations.

Typically in the installation described the flue tube 2 is preferably of a diameter such that the aperture 9 in which it is received is of the order of 50mm diameter. This is substantially smaller than the apertures generally required for known type flue systems which are typically of 125mm diameter.

Claims (10)

1. A flue system adapted to be connected to a heating appliance to remove products of combustion therefrom, comprising a flue terminal box having at least one inlet for air and at least one outlet for air and products, a flue chamber and a fan in the flue terminal box, a flue tube adapted to be attached at a first end to the heating appliance to receive the products therefrom and at a second end remote from the heating appliance being provided with a mixing adapter which extends into the flue chamber and has a first end received by and fixed in the second end of the flue tube for the products received by the flue tube to pass through the mixing adapter and enter at a second end into the flue chamber intermediate the fan and the outlet, and the fan being arranged to blow air along the flue chamber transversely of the direction of flow of the products through the mixing adapter, to draw the products into the flue chamber from the flue tube by way of the mixing adapter, and blow the products along the flue chamber away from the fan to exit from the flue terminal box at the outlet.

2. A flue system according to claim 1 wherein the fan is arranged to blow in a direction substantially perpendicular to the direction of the flow of products through the mixing adapter.

3. A flue system according to claim 1 or claim 2 wherein the mixing adapter has its first end received as a sliding fit and then fixed in the second end ofthe flue tube.

4. A flue system according to any preceding claim wherein the flue tube and mixing adapter are each substantially cylindrical in shape, and at the second end of the mixing adapter 21 part of the wall of the mixing adapter is 20 9 cut away to form a C-shaped portion of the wall within the flue chamber which acts to direct products leaving the mixing adapter towards the outlet.

5. A flue system according to any preceding claim wherein the flue chamber is substantially tubular in shape, the fan being at one end thereof and products leaving the flue chamber from the other end.

6. A flue system according to any preceding claim wherein the or each inlet and outlet is provided as a grid.

7. A flue system substantially as described herein with reference to the accompanying drawings.

8. A heating appliance connected to a flue system in accordance with any preceding claim by which products of combustion are extracted from the heating appliance.

9. A heating appliance according to claim 8 which has a burner or burners having a thermostatic control linked in with the rate of extraction of products of combustion by the fan of the flue system.

10. A heating appliance according to claim 8 or claim 9 which is a range type cooker or boiler. F.F. GORMAN & CO.