Motor-driven chimney draft system and an impeller for use in the system

Abstract

Impeller for a motor-driven chimney draft system, comprising a flue gas impeller (10) for creating, in a flue gas passage, a draft in a flue gas downstream direction. A flue gas deflector disk (20) is situated downstream relative to the flue gas impeller (10) and connected to the flue gas impeller (10); and a hub for connecting the impeller to an end portion of a driving shaft of a motor (100), wherein the hub and the end portion of the driving shaft, when connected, are both situated downstream relative to the flue gas deflector disk (20), the hub indirectly connected to the flue gas deflector disk (20) by means of intermediate members. Advantageously the intermediate members are impeller blades (40) connected to the downstream side of the flue gas deflector disk (20) and to a venting disk (30) with venting holes (31, 32) so as to form a turbine.

Claims

1. An impeller for a motor-driven chimney draft system, the impeller comprising: a flue gas impeller for creating, in a flue gas passage, a draft in a flue gas downstream direction, a flue gas deflector disk for deflecting the flue gas, the flue gas deflector disk situated downstream relative to the flue gas impeller and connected to the flue gas impeller, a venting disk with venting holes therein and arranged at the downstream side of the flue gas deflector disk and at a distance therefrom so as to define a space between the flue gas deflector disk and the venting disk, impeller blades being arranged in the space between the flue gas deflector disk and the venting disk, the impeller blades directly connecting the flue gas deflector disk and the venting disk so as to establish a sole interconnection between the flue gas deflector disk and the venting disk, and a hub for connecting the impeller to an end portion of a driving shaft of a motor, the hub being connected to the venting disk, wherein the hub and the end portion of the driving shaft, when connected, are both situated downstream relative to the flue gas deflector disk, wherein the impeller, when rotating, draws flue gas downstream towards the flue gas deflector disk where it is deflected outwards in a radial direction and through openings in the sides of the system, thereby preventing the flue gases from contacting the driving shaft.

2. The impeller according to claim 1, wherein the flue gas deflector disk has a larger diameter than the venting disk.

3. The impeller according to claim 2, wherein a peripheral edge portion of the venting disk is angled away from the flue gas deflector disk.

4. The impeller according to claim 2, wherein: the flue gas impeller is an axial impeller, and the flue gas impeller and the flue gas deflector disk are interconnected by a shaft with a space between the flue gas impeller and the flue gas deflector disk, the space constituting a flow path for flue gases.

5. A motor-driven chimney draft system, comprising: an impeller according to claim 2; and a motor having a driving shaft, wherein an end portion of the driving shaft is connected to the hub.

6. The impeller according to claim 1, wherein a peripheral edge portion of the venting disk is angled away from the flue gas deflector disk.

7. The impeller according to claim 6, wherein: the flue gas impeller is an axial impeller, and the flue gas impeller and the flue gas deflector disk are interconnected by a shaft with a space between the flue gas impeller and the flue gas deflector disk, the space constituting a flow path for flue gases.

8. A motor-driven chimney draft system, comprising: an impeller according to claim 6; and a motor having a driving shaft, wherein an end portion of the driving shaft is connected to the hub.

9. The impeller according to claim 1, wherein: the flue gas impeller is an axial impeller, and the flue gas impeller and the flue gas deflector disk are interconnected by a shaft with a space between the flue gas impeller and the flue gas deflector disk, the space constituting a flow path for flue gases.

10. A motor-driven chimney draft system, comprising: an impeller according to claim 9; and a motor having a driving shaft, wherein an end portion of the driving shaft is connected to the hub.

11. A motor-driven chimney draft system, comprising: an impeller according to claim 1; and a motor having a driving shaft, wherein an end portion of the driving shaft is connected to the hub.

12. The chimney draft system according to claim 11, further comprising a motor-bearing plate fixed to the motor and situated between the motor and the impeller, the motor-bearing plate having a central opening receiving the driving shaft, and one or more openings allowing air to flow therethrough towards the impeller.

13. The chimney draft system according to claim 12, wherein the central opening allows air to flow therethrough towards the impeller.

14. The chimney draft system according to claim 12, wherein the system has means for attaching the system to a chimney.

15. The chimney draft system according to claim 11, wherein the system has means for attaching the system to a chimney.

16. The impeller according to claim 1, wherein the venting disk has a single opening and is connected to the hub via a flue gas impeller shaft at the single opening.

17. The impeller according to claim 1, wherein the flue gas impeller shaft has an airtight connection with the venting disk.

18. The impeller according to claim 1, wherein the impeller blades, when rotating, draws cool air through the venting holes and radially outward, thereby cooling the flue gas deflector disk.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a longitudinal section through a motor-driven chimney draft system having an impeller acceding to the invention;

(2) FIG. 2 shows the central portion of FIG. 1 on a larger scale;

(3) FIG. 3 shows a cross section through the system in FIG. 1 along the line III-III; and

(4) FIG. 4 shows a cross section through the system in FIG. 1 along the line IV-IV.

DETAILED DESCRIPTION OF THE INVENTION

(5) In FIGS. 1 and 2 is shown a longitudinal section through a motor driven chimney draft system according to the invention. The system has means, in this case a flange 110, for attaching the system to the outlet opening of a chimney.

(6) Within a housing 111 the system has a flue gas impeller 10, which in this embodiment is an axial impeller with flue gas impeller blades 11 fixed to a flue gas impeller hub 12 on a hollow flue gas impeller shaft 13. When the flue gas impeller 10 is driven in rotation by a driving motor 100 in the housing, the flue gas impeller will create a draft in a downstream direction. When the system is attached to the flue gas outlet opening of a vertical chimney and in a position as shown in FIG. 1, the downstream direction is upwards, but other orientations are possible. A flue gas deflector disk 20 is situated downstream relative to the flue gas impeller 10 and is connected to the flue gas impeller 10 through the shaft 13 and the hub 12. When the flue gas impeller 10 is driven in rotation flue gas will be forced towards the flue gas deflector disk 20 where the flue gas will be deflected into a radial direction and leave the system through openings in the sides of the system. The flue gas deflector disk 20 has no openings and its connection to the hollow flue gas impeller shaft 13 is airtight.

(7) The system has a motor 100 with a driving shaft 101. An end portion of the driving shaft 101 is received in a hub 102. The hub 102 is connected to an optional venting disk 30 at the downstream side of the flue gas deflector disk 20 and at an axial distance therefrom so as to define a space between the flue gas deflector disk 20 and the venting disk 30. The venting disk 30 has plurality of through-going openings 31, 32. The flue gas deflector disk 20 and the venting disk 30 are interconnected by a plurality of impeller blades 40 extending in a radial direction.

(8) The motor 100 is fixed to a motor-bearing plate 103 which in turn is fixed to the housing 111. The motor-bearing plate 103 is situated between the motor and the venting disk 30 and has a central opening 104 receiving the hub 102 therethrough. Preferably, the central opening 104 has a larger diameter than the hub to provide an air passage. The peripheral edge portion of the venting disk 30 is angled away from the flue gas deflector disk 20 and towards the motor-bearing plate 103 leaving only a narrow slit therebetween.

(9) When the system is installed at the outlet opening of a chimney and forced draft in the chimney is desired the motor 100 is activated. Hereby the motor drives in rotation the rotatable assembly of the hub 102, the venting disk 30, the impeller blades 40, the flue gas deflector disk 20, the shaft 13, the hub 12 and the flue gas impeller 10. When thus driven in rotation the flue gas impeller 10 will create a draft, or assist an insufficient thermal draft, in the chimney. Flue gases will be forced towards the flue gas deflector disk 20 and deflected into a radially outward direction and will leave the system through openings in the sides of the system.

(10) When driven in rotation the assembly of the flue gas deflector disk 20, the venting disk 30 and the impeller blades 40 functions as a turbine which draws fresh air into the housing 111 through a peripheral slit 112 in the housing. Air in the housing will be drawn through openings 104, 104 in the motor-bearing plate 103 and towards the venting disk 30, through the openings 31 in the venting disk 30 and into the space between the venting disk 30 and the flue gas deflector disk 20 where the impeller blades 40 will force the air into a radially outward direction. Due to the angled edge portion of the venting disk 30 and the narrow slit between this portion and the motor-bearing plate 103 recirculation of air through the slit is minimised.

(11) The turbine assembly of the flue gas deflector disk 20, the optional venting disk 30 and the impeller blades 40 can be produced and sold as a separate unit, with or without the flue gas impeller 10, that can be exchanged as a spare part or retrofitted as an upgrade of existing chimney draft systems.