IE84706B1 - An open-fire effect gas fired inset heater - Google Patents

Abstract

ABSTRACT A gas fired heater (1) is provided and comprises a support structure (2) mounting an enclosed gas chamber (5) including an elongate distribution manifold (15). Alternate sets of open in—line slots (21) and parallel slots (22) orthogonal to the in—line slots (21) form a gas burner outlet. This provides very efficient gas distribution.

Description

An open-fire effect gas fired inset heater Introduction The present invention relates to an open-fire effect gas fired inset heater.

These are often referred to as "natural flame coal effect heaters". As more and more houses are heated generally by central heating systems, the need to have a fire in a room which provides the majority of the heat of the room, has dropped. Indeed, for environmental reasons, the burning of fossil fuels in open fires is being largely discouraged by legislation so as to generally prevent pollution of the atmosphere.

This has led more and more to people fitting these gas fired flame effect heaters in the conventional grate which heretofore burned solid fuel. They generally consist of an inset heater, comprising a burner directing flames up through incombustible so called coals. They are not alone being retrofitted but also fitted ab initio in the modern house when it is being built.

There are, however, certain problems with such heaters. As the need for the heater to supply a considerable amount of heat reduces and indeed the heater is more used for effect than anything else, the need to provide very high heat output has dropped, however, the need to provide a more aesthetically pleasing effect, with realistic flames, has increased. Also, there is a need to ensure an adequate distribution of flames through the coals. it has long been appreciated that there is a need to create different sizes and shapes of flame pattern, the burners in general feeding a manifold or chamber with a perforated gas distribution plate forming a top surface thereon. Various elaborate configurations of openings, orifice and slots have been provided. For example, European Patent Specification No. 0926445 A2 (CFM Majestic Inc.) describes a gas burner outlet formed by a plurality of openings, orifices and slots across the top wall of a distribution manifold. The specification describes various arrays of openings of different patterns and of different sizes and indeed, it suggests that any pattern may be used, depending on the arrangement of the fuel-like lumps mounted thereon and in particular to the distribution of flames which it is desired to achieve. However, it is suggested that such a random distribution of slots or openings, while theoretically likely to lead to a situation which mirrors a fire in use, this has not been the case. In fact, fires tend to burn, or more properly appear to burn, in a somewhat less random manner than might be appreciated. A further problem with such random openings is that difficulties can arise in unequal burning between adjacent openings. There are considerable technical advantages in having regular openings such that most burners heretofore proposed have in fact had regular openings such as slots, all oriented in the one way, either parallel to each other or in line. This ensures a more adequate distribution of the gas and more certain and efficient burning. At the same time, such an arrangement is not necessarily ideal as there is, in effect, a too regular flame now produced which does not have a fire-like effect. The present invention is directed towards going some way to solving this problem.

Statements of Invention According to the invention, there is provided an open-fire effect gas fired inset heater comprising:- a support structure; an enclosed gas chamber mounted in the support structure and comprising spaced-apart top and bottom walls bridged by front, rear and side walls; a gas inlet in a rear wall of the chamber; a gas distribution device comprising a pyramid shaped member mounted on the interior of the front wall with its apex spaced-apart from the gas inlet; an open bottomed upstanding elongate distribution manifold having front and side walls forming extensions of the respective gas chamber front and side walls and rear and top walls forming extensions of the gas chamber top wall; a gas burner outlet formed by a plurality of alternate sets of open slots across the top wall of the distribution manifold, one set of slots comprising a plurality l——l O‘\ of elongate in-line slots substantially parallel to the chamber front wall and the other a plurality of parallel transverse slots orthogonal to the in-line slots to form locations for high flame concentration interspersed with locations for low flame concentration; a filter across the inner surface of the top wall of the distribution manifold beneath the slots; a rear chamber adjacent the end wall of substantially the same configuration as the manifold having a solid top wall, the space between the rear chamber and manifold forming a fuel receiving recess; solid incombustible fuel-like lumps of ceramic fibre mounted across the top walls of the gas chamber and the manifold; and a pilot light device and associated ignition mechanism mounted adjacent the slots at one end of the manifold and operatively connected to a gas control valve for delivery of gas to the gas inlet and the pilot light device and for operation of the ignition mechanism.

In one embodiment of the invention, each set of parallel transverse slots comprises at least eight slots.

Further, there is provided a heater in which a heat transfer baffle extends ream/ardly of the gas chamber to form a heat sink.

Ideally, with the latter embodiment, an additional heat transfer baffle extends upwardly from the rear of the gas chamber. in one embodiment of the invention, the pilot light device incorporates flame sensing means operatively by connected to the gas control valve for cutting off the gas supply to the heater in the absence of a pilot light flame.

In a further embodiment of the invention, the heater comprises an oxygen depletion sensor for ambient air operatively connected to the gas control valve to shut off the gas supply to the heater, on the carbon monoxide level of the ambient air exceeding an acceptable level.

In another embodiment of the invention, the control valve comprises a drive mechanism connected to a microprocessor having a signal receiver and in which there is provided a hand-held transmitter for operation of the microprocessor and hence the control valve.

In a further embodiment of the invention, a variable aeration valve is provided for the gas chamber whereby the amount of air mixed with the gas for combustion may be controlled between that required for optimum combustion efficiency and a lower amount for incomplete combustion with a different flame colour and configuration.

The main advantage of the present invention is that the use of the slot arrangements provides greater distribution of the flames underneath the bed of "coals", thus producing a more realistic effect. Further, it has been found that by varying the spacing and shape of the slots, they are less likely to be clogged in use and thus again, a more efficient distribution of flame is provided. it has also been found that by having the flames rising in mutually orthogonal directions, any draught or any other environmental conditions are unlikely to prevent the even distribution of the flames underneath the "coals".

In effect, by having what is a relatively regular arrangement of slots, the burning is efficient and safe and at the same time, by having locations for high flame concentration interspersed with locations for low flame concentration, a realistic effect is achieved without the problems inherent in providing totally random openings.

Detailed Description of the Invention The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which:- Fig. 1 is a perspective view of a heater according to the invention, Fig. 2 is a rear view of the heater, Fig.3 is a perspective underneath view of part of the heater Fig. 4 is a perspective view from one side of an alternative construction of heater, Fig. 5 is a perspective view from the other side of the heater of Fig. 4, Fig. 6 is a rear view of the heater of Figs. 4 and 5.

Referring to the drawings and initially to Figs. 1 to 3 thereof, there is provided an open-fire effect gas fired inset heater, indicated generally by the reference numeral 1, for siting within a fireplace. The heater 1 comprises a support structure 2 mounting an enclosed gas chamber 5, illustrated from the rear in Fig. 3. The gas chamber 5 is mounted in the support structure and comprises an open-bottomed upstanding elongate distribution manifold, indicated generally by the reference numeral 15, having a front wall 16 forming an extension of the front wall 8 of the gas chamber 5 and end walls 17 forming extensions of the side walls 10 of the gas chamber 5. The manifold 15 in turn has a rear wall 18 and a top wall 19 forming extensions of the gas chamber top wall 6. A gas burner outlet is formed in the distribution manifold 5 by alternate sets of open slots, namely, in-line slots 21 which are substantially parallel to the chamber front wall 8 and parallel slots 22 orthogonal to the in-line slots 21. A filter, not shown, of a suitable incombustible material is fitted beneath the slots 21 and 22 to prevent burn back. A rear chamber, indicated generally by the reference numeral 25 similar to the manifold 15 is provided adjacent the rear of the gas chamber 5, except that this rear chamber 25 does not have any slots therein. A heat transfer baffle 26 extends rearwardly of the gas chamber 5 and a further additional heat transfer baffle 27 extends upwardly to the rear of the gas chamber 5. A further forwardly extending heat transfer baffle plate 28 is provided below which is mounted various controls, as will now be described.

Referring specifically to Fig. 3, the gas chamber 5 has a gas inlet including an air vent valve 30 fed by a main gas feed pipe 31 from a gas control valve 32 operated by a control knob 33. A gas distribution device comprising a pyramid shaped member (not shown) is mounted on the interior of the front wall with its apex spaced-apart from the gas inlet. This ensures adequate gas distribution. The gas control valve 32 feeds, by means of a pipe 34, a pilot light device 35, illustrated in Fig. 1. The gas control valve 32 feeds, by means of a wire 36, an ignition mechanism, indicated generally by the reference numeral 37 in Fig. 1. The air vent valve 30 is controlled by a rod 38 terminating in a knob 39. The mains gas inlet pipe is identified by the reference numeral 40.

In use, the heater 1 is mounted in a hearth of a fireplace and the portion between the manifold 15 and the rear chamber 25 and above the manifold 15 and across part of the gas chamber 5 are filled with fuel-like lumps of a suitable material. Such solid incombustible fuel-like lumps of ceramic fibre material are well known.

It is envisaged that the air intake may be varied so as to vary the combustion from full combustion, with relatively little flame, to less complete combustion where a yellow flame can be achieved with gas which is relatively pleasing. Since it is appreciated that the main purpose of the fire is not so much to give heat, as to provide a focal point in the room, the slight loss of fuel efficiency may be more than compensated for by the additional aesthetic effect. The advantage of the slots 21 and 22 is that it provides a very good distribution of flame across the heater and also provides a variation in the flame giving a more natural look to the flame produced. This further improves not alone the efliciency, but also the aesthetic appearance of the fire.

It will be appreciated that the controls operate in conventional manner.

It is envisaged that the pilot light may incorporate flame sensing means, operatively connected to the gas control valve 32 for cutting off the gas supply to the heater 1, in the absence of a pilot light flame.

Further, it is envisaged that an oxygen depletion sensor may be provided for ambient air. The oxygen depletion sensor is envisaged to be a carbon monoxide sensor such that when the level of carbon monoxide in the ambient air exceeds a preset amount, the oxygen depletion sensor sends a signal to the gas control valve to cut off the gas control valve.

Referring to Figs. 4, 5 and 6, there is illustrated an alternative construction of heater, indicated generally by the reference numeral 50, in which parts similar to those described with reference to the previous drawings, are identified by the same reference numerals. In this embodiment, there is provided a microprocessor 51 having a signal receiver (not shown) which in turn has an antenna 52 for reception of a signal. There is further provided a hand-held transmitter 53 for operation of the microprocessor which is connected to the control valve 32 to allow the control valve to be operated remotely.

Where necessary, the parts of the heater are made from incombustible materials.

In the specification the terms "comprise, comprises, comprised and comprising" or any variation thereof and the terms "include, includes, included and including" or any variation thereof are considered to be totally interchangeable and they should all be afforded the widest possible interpretation and vice versa.

The invention is not limited to the embodiment hereinbefore described, but may be varied in both construction and detail within the scope of the appended claims.

Claims (1)

1. An open—fire effect gas fired inset heater comprising:— a support structure; an enclosed gas chamber mounted in the support structure and comprising spaced-apart top and bottom walls bridged by front, rear and side walls; a gas inlet in a rear wall of the chamber; a gas distribution device comprising a pyramid shaped member mounted on the interior of the front wall with its apex spaced-apart from the gas inlet; an open bottomed upstanding elongate distribution manifold having front and side walls forming extensions of the respective gas chamber front and side walls and rear and top walls forming extensions of the gas chamber top wall; a gas burner outlet formed by a plurality of alternate sets of open slots across the top wall of the distribution manifold, one set of slots comprising a plurality of elongate in-line slots substantially parallel to the chamber front wall and the other a plurality of parallel transverse slots orthogonal to the in-line slots to form locations for high flame concentration interspersed with locations for low flame concentration; a filter across the inner surface of the top wall of the distribution manifold beneath the slots; a rear chamber adjacent the end wall of substantially the same configuration as the manifold having a solid top wall, the space between the rear chamber and manifold forming a fuel receiving recess; solid incombustible fuel-like lumps of ceramic fibre mounted across the top walls of the gas chamber and the manifold; and a pilot light device and associated ignition mechanism mounted adjacent the slots at one end of the manifold and operatively connected to a gas control valve for delivery of gas to the gas inlet and the pilot light device and for operation of the ignition mechanism. A heater as claimed in claim 1, in which each set of parallel transverse slots comprises at least eight slots. A heater as claimed in claim 1 or 2, in which a heat transfer baffle extends rean/vardly of the gas chamber to form a heat sink. A heater as claimed in claim 3, in which an additional heat transfer baffle extends upwardly from the rear of the gas chamber. A heater as claimed in any preceding claim. in which the pilot light device incorporates flame sensing means operatively connected to the gas control valve for cutting off the gas supply to the heater in the absence of a pilot light flame. A heater as claimed in any preceding claim comprising an oxygen depletion sensor for ambient air operatively connected to the gas control valve to shut off the gas supply to the heater, on the carbon monoxide level of the ambient air exceeding an acceptable level. A heater as claimed in any preceding claim, in which the control valve comprises a drive mechanism connected to a microprocessor having a signal receiver and in which there is provided a hand-held transmitter for operation of the microprocessor and hence the control valve. A heater as claimed in any preceding claim, in which a variable aeration valve is provided for the gas chamber whereby the amount of air mixed with the gas for combustion may be controlled between that required for optimum combustion efficiency and a lower amount for incomplete combustion with a different flame colour and configuration. A heater substantially as described herein with reference to and as illustrated in