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(11) | EP 0 480 595 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
Gas fire Gasfeuer Foyer à gaz |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] This invention relates to gas fires of the kind including a burner and a radiant unit arranged to be heated by flames from the burner to produce a source of radiant heat. It is known for the source of radiant heat to be supplemented by heated convection air from a duct which receives air drawn through the fire and which is traversed by a flue tube through which combustion products from the burner pass (US-A-2 789 554 and GB-A-2 177 490).
[0002] It has been proposed (US-A-2 789 554) to provide such a fire with a door in front of the radiant unit e.g of heat resistant glass, to enable the radiant unit to be enclosed: this increases the thermal efficiency of the fire since heated combustion gases are retained for longer in the fire.
[0003] However, if the flue outlet of the fire or chimney were to become blocked, the combustion products leaving the flue outlet would reverse direction and recirculate to the burner. The proportion of noxious gases in the combustion products in the fire would build up to dangerous levels, and these noxious products would permeate into the room via the convective duct.
[0004] The invention provides a gas fire comprising a burner, a radiant unit arranged to be heated by flames from the burner to produce a source of radiant heat, a transparent panel in front of the radiant unit, and a duct for the passage of convection air drawn through the fire, the duct being traversed by a flue tube through which combustion products from the burner pass, in order that the convection air is heated to supplement the heating from the radiant unit, the flue tube being provided with an opening so that, in the event of flue blockage, the combustion products can escape into the convection duct.
[0005] The presence of the opening prevents such a build-up of dangerous levels of noxious products since in the event of flue or chimney blockage, combustion products can escape into the room via the convection duct and the burner is allowed to continue operation within safe limits of combustion.
[0006] The opening is preferably in the side of the flue tube that is downstream relative to the flow of convective air, and a shield if preferably provided downstream of the opening.
[0007] The transparent panel enables the radiant unit to be enclosed, thereby improving the efficiency of combustion: it may be fixed, but may instead be movable e.g. it may be provided in a door which may be opened to enable the radiant heat from the radiant unit to be increased. In this case, a damper may be provided in the path of the combustion products through the flue outlet, which damper is movable to vary the flow of such products from the outlet, and the damper being coupled to the door by means of a linkage mechanism which causes the damper to open on opening of the door and partially to close on closure of the door.
[0008] A gas fire constructed in accordance with the invention will now be described by way of example with reference to the accompanying drawings, in which:
Figure 1 is a perspective view of the gas fire;
Figure 2 is a longitudinal cross section of a part of the gas fire; and
Figure 3 is a plan view of a flue tube.
[0009] The gas fire comprises a burner 1 arranged to direct gas rearwardly onto refractory radiation elements 2 in the form of imitation coal pieces supported on a refractory base 3. A pair of doors 4, 5 of heat resistant glass can be closed in front of the radiant units 2 to raise the temperature of combustion gases within the fire.
[0010] In addition to radiant heat from the fire, the fire includes a duct 6 in which convective air is heated to supplement the radiant heating. Air is drawn through inlets (not shown) at the bottom of the fire, and passes under the burner and imitation coal pieces into the duct (in the direction of the arrow A - Figure 2), and through the duct to outlets 7 which open into the room.
[0011] The duct 6 is traversed by several flue tubes 8, 9, 10, 11 (only one of which (10) is shown in Figure 2). Combustion gases from the fire must pass through these tubes in the direction of arrows B in order to reach the flue outlet 12 of the fire, and must also pass through box 13 above the duct 6, which contains baffle plate 14 having openings 15 offset with respect to the corresponding flue tubes. The heat exchanger thus created heats the air drawn into the bottom of the fire, which emerges into the room via the outlets 7.
[0012] A damper 16 is pivotable between two positions above the flue outlet. In dotted position, the flue outlet 12 is partially obscured and in the solid line position, the flue outlet 12 is opened. A linkage mechanism operated by doors 4, 5 pivots the damper 16 into its open position when the doors are open (to increase the draught and reduce the spillage of combustion products into the room) and into its partially closed position when the doors are closed (in which radiated heat is reduced but convective heat is increased). The damper takes up intermediate positions when one door is open or both doors are partially open.
[0013] The linkage mechanism comprises a pair of members 17, 18 which are pivoted when the doors are shut which in turn via a linkage (not shown) pivot a three sided frame 19 about pivot points 20 to lift and lower control surfaces 21.
[0014] A problem with such a fire is that, if the flue outlet 12 becomes blocked (e.g. due to a fall of soot in the chimney), or if the chimney itself becomes blocked, with the doors 4, 5 closed, combustion gases will tend to reverse direction with respect to arrows B and recirculate to the region of the burner. The combustion then produced gradually becomes very noxious and these noxious combustion products fall below the burner and coal pieces, whereupon they leak into the room via the inlets (not shown) to the convective duct at the bottom of the fire but mostly through the convective duct itself and out into the room via the outlets 7.
[0015] To overcome this problem and in accordance with the invention, some of the flue tubes 8, 10 are provided with bleed openings (10a, 10b, 10c, 10d in Figure 2). Thus, in the event of recirculation, combustion gases will escape (in the direction of the arrows C) into the convection air duct 6 and will gradually escape to the room. A dangerous build up of noxious gases is thus avoided and the burners remain operating within safe limits.
[0016] In order to prevent, for practical purposes, the flow of combustion gases sucking in the convective air flow when the fire is operating normally, a shield 22 is provided downstream of the bleed openings 10a-d relative to the direction of convective air flow, and the shield is cut away at 23 to provide an opening for combustion gases.
1. A gas fire comprising a burner, a radiant unit arranged to be heated by flames from
the burner to produce a source of radiant heat, a transparent panel in front of the
radiant unit, and a duct for the passage of convection air drawn through the fire,
the duct being traversed by a flue tube through which combustion products from the
burner pass, in order that the convection air is heated to supplement the heating
from the radiant unit, the flue tube being provided with an opening so that, in the
event of flue blockage, the combustion products can escape into the convection duct.
2. A gas fire as claimed in claim 1, in which there is provided an opening in the side
of the flue tube that is downstream relative to the flow of convective air, and a
shield is provided downstream of the opening.
3. A gas fire as claimed in claim 1 or claim 2, in which the transparent panel is formed
by a door which may be opened.
4. A gas fire as claimed in claim 3, in which there is provided a damper in the path
of combustion product through the flue outlet, which damper is movable to vary the
flow of such products from the outlet, the damper being coupled to the door by means
of a linkage mechanism which causes the damper to open on opening of the door and
partially to close on closure of the door.
1. Gasfeuerung mit einem Brenner, einer Strahlungseinheit, die ausgelegt ist, durch Flammen
von dem Brenner erwärmt zu werden, um eine Wärmestrahlungsquelle zu erzeugen, einer
transparenten Abdeckung vor der Strahlungseinheit, und einem Kanal für den Durchgang
von durch die Feuerung gezogener Konvektionsluft, wobei der Kanal von einem Flammrohr
durchlaufen ist, durch welches Verbrennungsprodukte von dem Brenner durchlaufen, damit
die Konvektionsluft erwärmt wird um die Erwärmung von der Strahlungseinheit zu ergänzen,
wobei das Flammrohr mit einer Öffnung versehen ist, so daß im Fall einer Flammrohrblockierung
die Verbrennungsprodukte in den Konvektionskanal entweichen können.
2. Gasfeuerung nach Anspruch 1, bei der in der relativ zum Konvektionsluftstrom stromabwärts
gelegenen Seite des Flammrohres eine Öffnung vorgesehen ist, und eine Schutzwand stromabwärts
der Öffnung vorgesehen ist.
3. Gasfeuerung nach Anspruch 1 oder Anspruch 2, in der die transparente Abdeckung durch
eine Tür, die geöffnet werden kann, gebildet ist.
4. Gasfeuerung nach Anspruch 3, in der in dem Weg des Verbrennungsproduktes durch den
Flammrohrauslaß ein Schieber vorgesehen ist, dieser Schieber bewegbar ist, um den
Strom derartiger Produkte von dem Auslaß zu ändern, wobei der Schieber mit der Tür
mittels eines Verbindungsmechanismus' gekoppelt ist, der bewirkt, daß der Schieber
sich beim Öffnen der Tür öffnet und beim Schließen der Tür teilweise schließt.
1. Radiateur à gaz comprenant un brûleur, un module rayonnant agencé pour être chauffé
par des flammes provenant du brûleur pour produire une source de chaleur rayonnante,
un panneau transparent en face du module rayonnant, et un conduit pour le passage
d'air de convection aspiré à travers le radiateur, le conduit étant traversé par un
tube de fumées par lequel passent les produits de combustion provenant du brûleur,
afin que l'air de convection soit chauffé pour s'ajouter au chauffage provenant du
module rayonnant, le tube de fumées étant pourvu d'une ouverture de sorte que, en
cas d'obturation du conduit de fumées, les produits de combustion puissent s'échapper
dans le conduit de convection.
2. Radiateur à gaz selon la revendication 1, dans lequel il est prévu, dans le côté du
tube de fumées, une ouverture qui est en aval suivant l'écoulement de l'air de convection,
et dans lequel un écran est prévu en aval de l'ouverture.
3. Radiateur à gaz selon la revendication 1 ou la revendication 2, dans lequel un panneau
transparent est formé par une porte qui peut être ouverte.
4. Radiateur à gaz selon la revendication 3, dans lequel il est prévu un registre dans
le trajet des produits de combustion dans l'orifice de sortie des fumées, lequel registre
est mobile pour modifier le débit de ces produits issus de l'orifice de sortie, le
registre étant accouplé à la porte au moyen d'un mécanisme de liaison qui fait que
le registre s'ouvre lors de l'ouverture de la porte et se ferme partiellement lors
de la fermeture de la porte.