GB2068530A - Open-closed boilers - Google Patents

Abstract

A boiler for mounting in an open fire place, or a free standing boiler an opening (7) in a front wall (6) comprises a combustion chamber (5), communicating with the combustion chamber (5), a closure member (19) slidable from a closed position covering the opening (7) to an open position above the opening, and a hood (32) defining a recess to receive and conceal the closure member (19) in the open position. The boiler (1) also includes an ambient air heater having an air inlet (47) and outlet (48). <IMAGE>

Description

SPECIFICATION A boiler The present invention relates to a domestic boiler and in particular to either a back boiler for mounting in an open fire place or a free standing boiler for a room.

Conventional back boilers in general comprise a pair of cast or welded side water tanks connected by a rear water tank and are adapted for mounting in a fire place. Unfortunately, such back boilers tend to be inefficient in use. There are two principal reasons for this. Firstly, since in construction back boilers are substantially similar to an open fire grate in that they have an open front, a large proportion of the flue draught enters the flue directly through tha open front, thus leaving only a small proportion of the flue draught to pass through the combustion area of the boiler to aid combustion. Attempts have been made to close the open front of such boilers with a door.

However, these attempts have been aesthetically unacceptable since, in general, such back boilers are fitted in a sitting room fire place and people prefer to sit around an open fire.

Secondly, another cause of inefficiency in conventional back boilers results from the relatively small area of heat exchanging surfaces exposed to the flue gases. Attempts to overcome this problem have resulted in back boilers being provided with additional water tanks mounted above the combustion chamber joining the side tanks. However, this solution has only partly overcome the problem.

Accordingly, there is therefore a need for a boiler, both a back boiler and a free standing boiler hereinafter referred to as a boiler with a relatively improved operating efficiency.

The present invention is directed towards providing such a boiler.

According to the invention there is provided a boiler of the type hereinbefore described having a front opening communicating with a combustion chamber, the front opening being closed by a closure member, slideable from a closed position covering the opening to an open position above the opening, and a hood projecting outwardly from the front of the boiler and forming with the front of the boiler a recess to receive and conceal the closure member in the open position.

Preferably, the closure member is a rectangular door slideable in guides mounted on either side of the opening, a counter weight being operatively connected to the door by a flexible member passing over a pulley above the front opening to assist opening and closing of the door.

Advantageously, an ambient air heater is provided in the boiler above the combustion chamber, the ambient air heater having an ambient air inlet and an ambient air outlet communicating with the ambient air, the air inlet being below the air outlet.

In one embodiment of the invention the ambient air inlet and ambient air outlet are in the front of the boiler in the recess formed by the hood, an air deflector, projecting outwardly and downwardly from the front of the boiler intermediate the inlet and outlet to deflect air into the inlet, and at least one ambient air inlet being provided in the top portion of the hood to deliver the heated ambient air.

In another embodiment of the invention the boiler comprises a rear tank, a pair of outwardly directed side tanks forming extension of the rear tank and front wall joining the side tanks, the front opening being formed in the front wall, the lower portion of the side and rear tanks forming the boiler combustion chamber.

The invention will be more clearly understood from the following description of some preferred embodiments thereof given by way of example only with reference to the accompanying drawing, in which: Fig. 1 is a perspective view of a back boiler according to the invention.

Fig. 2 is a vertical section through the boiler of Fig. 1, Fig. 3 is a side view of the boiler of Fig. 1, Fig. 4 is a cross-sectional plan view on the line lV-IV of Fig. 2 with some detail omitted, Fig. 5 is a cross-sectional plan view on the line V-V of Fig. 2, Fig. 6 is a cross-sectional plan view on the line VI--VI of Fig. 2, and Fig. 7 is a view similar to Fig. 2 of a back boiler according to another embodiment of the invention.

Referring to the drawings and initially to Figs. 1 to 6 thereof there is provided a back boiler according to the invention indicated generally by the reference numeral 1 for mounting in a fire place (not shown). The back boiler 1 comprises a rear tank 3 and a pair of outwardly directed side tanks 4 forming extensions of the rear tank 3. The lower portions of the rear and side tanks form a lower combustion chamber 5. A front wall 6 joins the side tanks 4 and a rectangular front opening 7 as will be described below is provided in the front wall 6 and communicates with the combustion chamber 5. At least a pair of transverse tanks 8, in this embodiment of the invention five spaced apart tanks 8 are mounted above the combustion chamber 5, between and interconnecting the side tanks 4. it can be seen that the transverse tanks 8 are spaced apart from the rear tank 3.Thus, the spaces between adjacent transverse tanks 8 and between the rear tank 3 form passages for the flue gases. A lower tank 9 is mounted adjacent the front wall 5 below the opening 7 and joins the side tanks 4 this lower tank 9 is, in use, in contact with the fire in the combustion chamber 5 thus effectively retaining the fuel. A water inlet 11 and a water outlet 1 2 are provided to and from the boiler for connecting to a domestic hot water cylinder or a central heating assembly (not shown). A grate 1 4 to support the fuel in the combustion chamber 5 is mounted on brackets 1 5 projecting inwardly from the lower end of the side tanks 4.

The front opening 7 in the front wall 6 is closed by a closure member, in this embodiment of the invention a door 19. The door 19 comprises a steel framework 20 retaining a central glass panel 21. Guide rails 22 on each side of the opening 7 permit the door 1 9 to slide from a closed position as shown in Fig. 1 to an open position above the opening 7, see Fig. 2. The operation of the door 19 is assisted by a counter weight 24. Flexible members provided by chains 26 passing over pulleys 27 connect the counterweight 24 to the door 1 9. The pulleys are rotatable on brackets 28 mounted on the front wall 6. A support member 30 which will be described below slideably supports the counter weight 24.

A hood 32 is mounted by screws 33 to a mounting plate 34 projecting from the front wall 6. The hood projects outwardly from the front wall 6 and forms with the front wall 6 a recess 36 to receive and conceal the door 1 9 in the open position as can clearly be seen in Fig. 2. It will thus be appreciated that with the door 1 9 in the open position the boiler 1 can be used as an open fire and still remain aesthetically pleasing.

An ambient air heater indicated generally by the reference numeral 40 is mounted above the combustion chamber 5 in a flue gas chamber 37.

The flue gas chamber 37 is formed by rear and side walls 38 and 39 projecting respectively from the rear and side tanks 3 and 4 and the front wall 6 extends upwardly to join the side walls 39. A top member 31 joins the front rear and side walls 6, 38 and 39 and is provided with a flue outlet 29 adapted for connection to a chimney flue (not shown). The heater 40 is formed from a box comprising a top and bottom plate 41 and 42 respectively, both welded to the front wall 6. Rear and side plates 43 and 44 respectively join the top and bottom plates 41 and 42. A divider plate 45 joins the side plates 44 to the front wall 6 and defines with the top, bottom and rear plates a passage for the ambient air.It can be seen from the drawings and in particular from Fig 6 that the rear and side plates 43 and 44 are spaced apart from the rear and side walls 38 and 39 respectively, thereby forming a passageway for the flue gases. An air inlet 47 and an outlet 48 are provided to the heater 40 by elongated slots in the front wall 6 within the recess 36 formed by the hood 32. A deflector plate 49 projecting from the front wall 6 deflects air into the air inlet 47. A row of air outlet holes 50 is provided in the top of the hood 32 to deliver air from the air outlet 48 to the room.

The support member 30 which slideably supports the counter weight 24 as already described is welded to and projects downwardly from the lower edge of the deflector plate 49. A stop bracket 51 is provided at the lower end of the support member 30 to retain the counter weight 24 when the door 19 is fully open. Accordingly, it can be seen, in particular, from Fig. 2 that when the door 19 is in the open position the hood 32 conceals both the door and the counter weight and indeed the upper portion of the boiler and accordingly the boiler 1 can be used as an open fire.

A duct 52 with an air inlet 53 extends from thte recess 36 to deliver warm airthrough an air inlet 54 to the combustion chamber 5. A closure flap 55 closes the inlet 53 and is connected by a chain 56 to a thermostat 57 which is mounted in one of the transverse tanks 8. The thermostat operates in conventional manner opening or closing the flap 55 depending on the temperature of the water.

The advantage of having the closure flap 55 controlled by the thermostat 57 is that at night the thermostat can be set at a low setting. Thus the closure flap 55 will be retained substantially closed throughout the night causing slow burning of the boiler.

A removable ash pan 58 is provided below the grate 14, and access to the ash pan 58 is provided through a door 59.

In operation, a fire is lit in conventional manner in the combustion chamber 5 on the grate 14 the combustion gases rise up as indicated by the arrows A between the transverse tanks 8 and the rear and side tanks 3 and 4. The fire and combustion gases heat the water in these tanks as well as in the lower tank 9. The combustion gases then proceed to impinge against the bottom plate 42, rear and side plates 43 and 44 and the top plate 41 of the ambient air heater 40 and exit through the flue outlet 29. Ambient air indicated by the arrows B is drawn by convection into the air heater 40 through the air inlet 47 and delivered into the room from the air outlet 48 through the air outlet holes 50.

When it is desired to use the boiler as an open fire the door 7 is raised to the open position beneath the hood 32. Needless to say, when it is not desired to use the boiler as an open fire to increase the efficiency the door 7 is closed.

Fig. 7 shows a boiler according to another embodiment of the invention. This boiler is substantially similar to the boiler described with reference to Figs. 1 to 6 and like components are referred to by similar reference numerals. In this embodiment of the invention the construction of the hood 32 differs from that just described in that the hood is mounted on the mounting plate 34 by engaging a slot formed between retaining plates 60 fixed to the mounting plate 34.

Needless to say, it will be appreciated that it is not necessary to provide an ambient air heater such as described above with the boiler according to the present invention. However, the ambient air heater is a particularly useful way of further increasing the efficiency of the boiler.

Further, it will be appreciated that while the boiler according to the present invention has been described as a back boiler adapted for mounting in a fire place that it would be relatively easy to provide the boiler as a free standing boiler.

It will also be appreciated that while the use of a counter weight to assist the operation of the doors is particularly advantageous, this is not necessary. In fact it is envisaged that other means for operating the door could be used without departing from the scope of the invention.

Needless to say, it will also be appreciated that the shape, number and location of the various water tanks may be varied as required having regard to ensuring the adequate heat transfer and efficient combustion of fuel.

Furthermore, it will be appreciated that it is not necessary for the air inlet closure flap to be controlled by a thermostat, and similarily it is not necessary for the air to be drawn from the recess beneath the hood. While the ambient air heater has been described as being of particular shape and construction other shapes and constructions are envisaged. It will also be appreciated that other shapes and constructions of the hood could be used. Needless to say, other shapes and constructions of doors and front openings could be used.

Claims (14)

1. A boiler of the type hereinbefore described having a front opening communicating with a combustion chamber, the front opening being closed by a closure member, slideable from a closed position covering the opening to an open position above the opening, and a hood projecting outwardly from the front of the boiler and forming with the front of the boiler a recess to receive and conceal the closure member in the open position.

2. A boiler as claimed in claim 1 in which the closure member is a rectangular door slideable in guides mounted on either side of the opening, a counter weight being operatively connected to the door by a flexible member passing over a pulley above the front opening to assist opening and closing of the door.

3. A boiler as claimed in claims 1 or 2 in which an ambient air heater is provided in the boiler above the combustion chamber, the ambient air heater having an ambient air inlet and an ambient air outlet communicating with the ambient air, the air inlet being below the air outlet.

4. A boiler as claimed in claim 3 in which the ambient air inlet and ambient air outlet are in the front of the boiler in the recess formed by the hood, an air deflector, projecting outwardly and downwardly from the front of the boiler intermediate the inlet and outlet to deflect air into the inlet, and at least one ambient air inlet being provided in the top portion of the hood to deliver the heated ambient air.

5. A boiler as claimed in any of the preceding claims in which the boiler comprises a rear tank, a pair of outwardly directed side tanks forming extensions of the rear tank and a front wall joining the side tanks, the front opening, being formed in the front wall, the lower portion of the side and rear tank forming the boiler combustion chamber.

6. A boiler as claimed in claims 3 and 5 in which the ambient air heat exchanger is mounted in an exhaust flue chamber above the combustion chamber, the exhaust flue gas chamber being formed by a pair of side walls joined by a rear wall and an extension of the front wall, the side and rear walls projecting upwardly from the side and rear tanks respectively, the ambient air heat exchanger being a box formed by top and bottom plates projecting inwardly from the front wall and joined by side plate and a rear plate, the side and rear plates being spaced apart from the side and rear walls respectively to define a passage for flue gases, a divider plate projecting from the front wall and joining the side plates intermediate the top and bottom plates and spaced apart from the rear plate, the divider plate defining with the top, bottom and rear plates a passage for the ambient air, and the ambient air inlet and outlet being formed by substantially horizontal elongated slots in the front wall.

7. A boiler as claimed in claims 2 and 5 or 6 in which the counter weight is provided by an elongated horizontal bar connected at each end by a pair of flexible members to the closure member, the bar being slideably supported on a support member projecting downwardly and outwardly from the lower edge of the air deflector plate.

8. A boiler as claimed in any of the preceding claims in which an air inlet to the combustion chamber of the boiler is closed by an inlet closure member, the inlet closure member being operatively connected to a thermostat mounted in the boiler for automatic opening and closing of the air inlet.

9. A boiler as claimed in any of claims 5 to 8 in which at least a pair of spaced apart transverse tanks are mounted above the combustion chamber between and interconnecting the side tanks and spaced apart from the rear tank, and a lower tank joining the side tanks is mounted below the front opening.

10. A boiler as claimed in any of the preceding claims in which the boiler is adapted to accommodate a removable ash pan beneath the combustion chamber.

11. A boiler as claimed in any of the preceding claims in which the boiler is adapted for mounting in an open fireplace.

12. A boiler as claimed in any of claims 1 to 10 in which the boiler is adapted to be a free standing boiler.

1 3. A boiler substantially as described herein with reference to and as illustrated in Figs. 1 to 6.

14. A boiler substantially as described herein with reference to and as illustrated in Fig. 7.