GB2189025A

GB2189025A - Gas fires

Info

Publication number: GB2189025A
Application number: GB08626182A
Authority: GB
Inventors: James Stanford; Arthur Chesworth; William Easby; Frank Drummond Blower
Original assignee: Robinson Willey Ltd
Current assignee: Robinson Willey Ltd
Priority date: 1986-04-08
Filing date: 1986-11-03
Publication date: 1987-10-14
Anticipated expiration: 2006-11-03
Also published as: GB8608479D0; GB2189025B; GB8626182D0

Abstract

A glass fronted gas fire has a firebed of fuel simulation material (52) and two burners (55) and (56). A connected air inlet (57) leads through a double pass heat exchanger (58) to outlet (59). Hot exhaust gases flow through the heat exchanger and enter a gather box (62). There are no direct openings from the gather box into the flue (67) but openings leading into downwardly directed passages, one at each side of the fire. Openings from near the top of each passageway allow exhaust gas into the flue. When flue back pressure is experienced downflow tends to take place down these passageways rather than entering the gather box. <IMAGE>

Description

SPECIFICATION Gas fires This invention relates to gas fires of the kind in which gas flames flicker through a nonburning simulation of fuel and present a realistic imitation of a solid fuel burning fire. Such fires are inefficient in their production of useable heat and an object of this invention is to provide a gas fire of this kind which has improved efficiency.

The invention provides a gas fire having a non-burning simulation of solid fuel and a gas burner located to direct flames to said simulation, the fire having convected air ducts leading to a heat exchanger means comprising one or more pans having openings through which exhaust gases from the flames may enter them and connected air passages therearound communicating with the convected air ducts.

In another aspect the invention provides a gas fire having a heat exchanger comprising one or more pans having a length greater than the front-to-back dimension of the fire and bent at an angle such as to fit adjacent the top and rear surfaces of the fire. There may be an exhaust gather box into which the exhaust gases are directed before leaving the fire. The gather box may be associated with draught diverting means and/or means for preventing rubble from blocking its outlet opening.

The convected air ducts may be defined between ribs on a webbing adjacent the rear of the fire. Said webbing may be of cast aluminium. There may also be ribs extending into the exhaust gases.

The front of the fire may have a full or partial glass cover.

Specific embodiments of the invention are shown in the accompanying drawings, in which: Figure 1 is a side section through a gas fire, Figure 2 is a detail of a side section through the gas fire of Fig. 1 taken at one side of the fire, Figure 3 is a perspective view of a gas fire with the firebed removed, Figure 4 is a side section through the fire of Fig. 3 showing the fireplace opening, and the firebed in dotted outline, Figure 5 is a horizontal section through the fire of Fig. 4 with the firebed removed, taken on the line X-X, Figure 6 is a scrap view of part of another gas fire showing the heat exchanger, and Figure 7 is a side section through another gas fire showing the fireplace opening.

Referring first to Figs. 1 and 2, a gas fire has a glass front full closure plate (50) sloping back at an angle of 3 to the vertical. Behind the plate is a firebed of non-burning fuel simu lation material, the firebed comprising a main mass (52) having openings (53) and a few (e.g. 4 or 5) loose pieces (54) on top. Beneath the fuel simulation are an aerated gas burner (55) and a non-aerated or lightly aerated burner (56). The aerated flames heat the fuel simulation causing it to radiate heat through the glass front, while the non-aerated flames flicker through the openings (53) and give greater realism to the appearance of the fire.

Beneath the fire a convected air inlet (57) leads around a double pass heat exchanger (58) to an outlet (59). Hot exhaust gas from the firebed travels along the paths shown by the arrows. It enters the heat exchange system at (60) and divides, a minor part of the flow being directly through connections (61) into an exhaust gather box (62). The major part of the divided flow passes down a front heat exchanger pan (63) across connections (64) to a rear heat exchanger pan (65) and up to join the first part of the flow in the gather box (62).

The gather box (62) has no direct opening into flue (67), extends fully across the top width of the fire, and is situated above the heat exchanger outlets. At each end, as seen in Fig. 2, the gather box is connected to a downwardly extending funnel (69) so that the exhaust gases follow the path shown by the arrow around lip (70) and rearwardly into the flue (67). Downwardly directed passageways (72) at each side of the fire terminate in open ends beneath lip (70). When the flue (67) experiences a back pressure due to a wind gust, a downflow may occur. This flow takes the easiest path and therefore passes down passageways (72) rather than entering the fire's exhaust passages.

The fire is partially inset into a fireplace, the wall location being shown at (73). The protrusion of the fire from the fireplace is about 130 mm. The heat exchanger comprises two very long pans, each between 300 and 400 mm in length. Thus a large amount of heat is transferred to the convected air. This length of pan is accommodated in the fire by bending the pans at an angle to a "banana" shape in order that part of the heat exchanger can be located above the firebed. Thus the pans fit neatly into the overall fire construction and give a minimum rearward projection to the fire which enables debris to collect between the fire back and back brick of the fire.

Referring now to Figs. 3 to 5, a gas fire has an open front and a firebed of non-burning fuel simulation material (12), through which real flames from gas burner (13) flicker. There may be two series of burners, as described in relation to Figs. 1 and 2. The gas fire fits into a fireplace opening (14) having a chimney knee (15) leading to a flue (16). A continuous space (17) is left between the gas fire and the back of the fireplace opening so that any rub ble falling down the chimney collects there.

The firebed comprises a tray containing the fuel simulation material which sits on ledge members (18) so as to leave a space therebeneath in which the burner (13) and gas supply lines (19) are located.

Beneath the burner a convected air inlet (20) leads to a plurality (four) of upwardly directed channels (21) at the rear of the fire. These channels lead into a heat exchanger chamber (22), round a single pass heat exchanger (23) and out into the space being heated through outlet (24). Channels (21) are formed by the co-operation of a length of cast aluminium webbing (25) [seen best in Fig. 3] with the rear wall (26) of the fire. As shown, the webbing has deep ribs on its rear surface and shallower ribs on its front surface. The front surface and front ribs are heated by the exhaust gas from the burner (13) and the heat transferred to the convected air in channels (21) by the rear surface and the deep rear ribs. The webbing is curved at its upper end to extend forwardly, thus guiding the exhaust gases to the upper front of the fire.

The exhaust gases then pass through three parallel tubular openings (30) at the top and front of the fire into the heat exchanger chamber (22). The gases pass through heat exchanger (23) into gather box (31), and thus through an opening into the flue (16). More heat is thus scrubbed from the exhaust gases and the efficiency of the fire increased. As seen in Fig. 3, the fire protrudes forwardly from the fireplace wall by about 100 mm. To fit it flush with the wall the chimney knee (15) may be removed, but a space (17) must be maintained. A hood (33) covers the upper part of the fire.

In Fig. 6 another form of heat exchanger and hood is shown, with other parts marked with the same reference numerals as in Figs.

3 to 5. The exhaust gases reaching the top of the fire chamber enter into two parallel rows of tubular openings (35), the higher row containing three openings and the lower row two openings staggered with respect to the openings in the higher row. A glass plate (36) depends at the front of the fire and reduces the amount of entrained air mixing with the exhaust gases and reducing their temperature.

After passing over the heat exchanger (23) the gases enter gather box (31) and leave through a single opening (37).

Fig. 7 shows another gas fire having an open front and a firebed of fuel simulation material (12), and again has similar items referenced by the same numerals as in Figs. 3 to 5. This fire employs a double pass heat exchanger, exhaust gases being guided into two rows of staggered openings (40) to pass into a first flat heat exchanger pan (41) and from there through two openings (42) into a second flat heat exchanger pan (43). From there the gases enter gather box (45) which extends into the flue (16). The gather box does not have any openings in its uppermost surface (46), but has a large side opening (47) on each side and another opening (48) facing the knee. Thus any rubble falling down the flue (16) slides off the inclined surface (46) and falls into the space (17). The inclined surface (46) also serves to scrub more heat from the exhaust gases. This fire may have gas burners as described in relation to Figs. 1 and 2.

It will noted that this fire is flush with the fireplace wall (14) except for the protrusion of the front ends of the heat exchanger pans which are hidden by the hood (33).

in alternative arrangements the fires may have telescopic hoods which can be extended or retracted to fit different heights of fireplace openings.

Claims

1. A gas fire having a non-burning simulation of solid fuel and a gas burner located to direct flames to said simulation, the fire having convected air ducts leading to a heat exchanger means which comprises one or more pans having openings through which exhaust gases from the flames may enter them and air passages therearound communicating with the convected air ducts.

2. A gas first as claimed in claim 1, wherein said heat exchanger means comprises one or more pans having a length greater than the front-to-back dimensions of the fire and bent at an angle such as to fit adjacent the top and rear surfaces of the fire.

3. A gas fire as claimed in claim 2, wherein the or each pan is between 300 and 400 mm in length and bent into a banana shape.

4. A gas fire as claimed in any of claims 1 to 3, wherein the heat exchanger means comprises a double pass arrangement of two pans through which the exhaust gases pass in succession.

5. A gas fire as claimed in any of claims 1 to 4, wherein there is an exhaust gather box into which the exhaust gases pass after the heat exchanger means, there being direct or indirect connections from the gather box for entry into a flue.

6. A gas fire as claimed in claim 5, wherein said gather box has no direct opening for connection to the flue but is connected to one or more downwardly-directed passages, there being a flue connection into the or each passage.

7. A gas fire as claimed in claim 6, wherein said flue connection is located at or near the upper end of the passage.

8. A gas fire as claimed in claim 6 or claim 7, wherein the path followed by the exhaust gases from the gather box to the flue connection includes a lip beneath which the exhaust gases must flow.

9. A gas fire as claimed in claim 5, wherein said gather box has no opening in its upper surface but has openings in substantially vertical surfaces for the outlet of flue gases into a flue.

10. A gas fire as claimed in any of claims 1 to 9, wherein the convected air ducts are defined between ribs on a webbing adjacent the rear of the fire.

11. A gas fire as claimed in any of claims 1 to 10 having a full or partial glass front.

12. A gas fire as claimed in claim 11, wherein said glass front is full and slopes back at an angle of 3 to the vertical.

13. A gas fire as claimed in claim 1, wherein said heat exchanger means comprises one or more pans having a length greater than the front-to-back dimension of the fire and accommodated therein by being located at an angle and having its front end protruding from the fire, a canopy hiding the said protruding end.

14. A gas fire substantially as described hereinbefore with reference to Figs. 1 and 2; Figs. 3, 4 and 5; Fig. 6 or Fig. 7 of the accompanying drawings.