WO1994014009A1

WO1994014009A1 - Combined open fire and central heating boiler

Info

Publication number: WO1994014009A1
Application number: PCT/FI1992/000345
Authority: WO
Inventors: Matti LÄSPÄ
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-12-17
Filing date: 1992-12-17
Publication date: 1994-06-23
Anticipated expiration: 1995-06-17

Abstract

The invention is related to a central heating unit comprising a solid-fuel fired firebox (1) suited for combusting the fuel, a hole (19) from the firebox to a post-combustion chamber (2), channels from the post-combustion chamber to the flue stack, a storage tank (9) surrounded by insulating walls (26) and having the firebox (1) adapted close to it so as to make the water space enclose the firebox at least partially, and the required piping. The invention is implemented so that the firebox (1) can serve as both a boiler and an open fireplace, that the combustion air in the open fireplace use and in the boiler use are passed via essentially different paths, that the flue gases are directed to the flue stack in the open fireplace use and in the boiler use via essentially different paths, and that a pump and piping space (11), advantageously housing at least a circulation pump (12) and necessary means for connecting the storage tank to the central heating and water supply circuits, is adapted to inside the insulating walls (26).

Description

COMBINED OPEN EIRE AND CENTRAL HEATING BOILER.

The present invention relates to a central heating unit according to the preamble of claim 1.

Conventional solid-fuel fired central heating equipment intended for use in family houses comprises a separate boiler and a storage tank. Use of such equipment requires a separate boiler room, which increases the construction costs of the house.

Known in the art is from FI laid-open publication 53,881 such a central heating unit which comprises the storage tank, expansion tank and required piping of the heating unit, whereby the storage tank and the expansion tank are adapted into a single tank having the heating unit arranged to be at least partially enclosed by the water space. The embodiment is intended for use as a boiler alone, thus requiring a separate open fireplace or baking oven in the apartment.

Moreover, the prior-art embodiments require a space separate from the central heating unit for the circulation pump and necessary valves, which increases construction costs and complicates piping layout.

It is an object of the present invention to provide a novel type of central heating unit capable of overcoming the drawbacks of conventional techniques and offering wider applications.

The invention is characterized by what is stated in the characterizing part of claim 1. Furthermore, the specific embodiments of the central heating unit according to the invention are characterized by what is claimed in annexed claims 2-8. The approach according to the invention offers a plurality of significant benefits . The central heating unit according to the invention can be placed as an integrated package in a living room. This arrangement contributes to reduction of construction costs, since a separate boiler room becomes redundant. Owing to almost complete combustion, the heating unit according to the invention is free from any smell nuisance. As the central heating unit is enclosed in a contiguous insulation, the amount of dissipated heat is low. Also the heat produced in the open fireplace use of the unit can be utilized stored in the water of the storage tank. Location of the circulation pump and piping within the insulation of the central heating unit reduces heat losses and makes the layout of the piping easier. By virtue of the invention, a central heating unit is offered which when lined with a suitable material such as ceramic tiles looks most agreeable.

The invention is next examined with reference to the appended drawings, in which

Figure 1 is a sectioned front view of a central heating unit according to the invention;

Figure 2 is a sectioned side view of a central heating unit according to the invention used as an open fireplace;

Figure 3 is a sectioned side view of a central heating unit according to the invention used as a boiler; and

Figure 4 is a sectioned side view of an alternative embodiment of a central heating unit according to the invention.

With reference to the first embodiment illustrated in the drawing, the heat in the boiler unit is produced in a firebox 1. Above the firebox is adapted a post-combustion chamber 2 which also acts as a baking oven. The firebox and the post-combustion chamber communicate with each other via a hole 19. Under the firebox is located an ash pit 7. Between the firebox and the ash pit is situated a grate 8. In the exemplifying embodiment the storage tank 9 and the expansion tank 10 of the boiler are combined into a single tank housing the firebox 1, the post-combustion chamber 2 and the ash pit 7 so as make the water space enclose said elements at least partially. The entire central heating unit is surrounded by insulated walls 26. To the inside of the insulated walls is adapted a pump and piping space 11 housing at least a circulation pump 12 and required valves for connecting the central heating unit to the water service and heating circuits.

The firebox 1 can be used for dual functions. The firebox acts as an open fireplace (Fig. 2) when the loading door 24 of the firebox is removed or kept open. In this function the discharge of flue gases is directed by a control means 22 to pass via a shorter route formed by a channel 23 to the flue stack. The arrows in the diagram denote the path of flue gases from the firebox to the flue stack. In the open fireplace use the amount of combustion air is not restricted.

In the embodiment according to the invention the post- combustion chamber 2 is also suited for use as a baking oven. Owing to the materials of the firebox and the post- combustion chamber, the interior of the post-combustion chamber 2 stays hot for extended periods.

When the firebox is used in the boiler mode (Fig. 3), the loading door 24 is kept closed. Then, the combustion air is passed to the firebox 1 via at least one air intake hole 4 from a preheating cavity 3 which provides preheating of the air. Also the air entering the post-combustion chamber is preheated. The post-combustion air is passed to the upper part of the firebox from a preheating cavity 5 via at least one hole 6. Air into the preheating cavities 3 and 5 is passed from outside the central heating unit. The flue gases are passed via a channel 21 to the flue stack. In this use the control means 22 directs the flue gases along the longer route to the flue stack. The path of the flue gases from the firebox to the flue stack is denoted by arrows in the diagram. In boiler use, heat recovery from the flue gases is more efficient than in the open fireplace use, because the longer path of the flue gases facilitates the utilization of the wider heat recovery surfaces of the storage tank 9.

The firebox 1 and the post-combustion chamber 2 are advan¬ tageously made from heat-resistant bricks, ceramic compound or equivalent material. Owing to this advantageous choice of materials and preheating of combustion air, the combus¬ tion temperature can be elevated sufficiently high to achieve almost complete combustion. Then, tar formation in the boiler is avoided and no smell nuisances occur.

In the exemplifying embodiment the pump and piping space 11 is located below the boiler. Thus, the entire central heating unit can be designed into a compact package suited for placing in the dwelling premises. The central heating unit can be lined with a suitable material such as ceramic tiles, whereby a particularly high-quality look is attained. With reference to Fig. 4, a preferred embodiment of the central heating unit is shown having the firebox loading door 24 and the door of the post-combustion chamber (baking oven) 2 located to opposite sides of the unit. Such a unit illustrated in the diagram can be located so that the door of the post-combustion chamber 2 opens to the kitchen, while the loading door of the firebox opens to, e.g., the fireplace room.

The storage tank 9 is provided with a coil 18 for the heat¬ ing the hot water supply. The piping 28, 30 is connected to the coil in a conventional manner. To the storage tank 9 is also inserted an electric heater element 17, which can be used for heating the water contained in the storage tank.

With reference to Fig. 1, the diagram also shows the rest of necessary piping for the central heating unit as well as the filling arrangement of the storage tank, the latter being disclosed in a separate patent application.

For those versed in the art it is obvious that the inven¬ tion is not limited by the exemplifying embodiment des¬ cribed above, but rather, can be varied within the scope and spirit of the annexed claims.

Claims

Claims :

1. A central heating unit comprising a solid-fuel fired firebox (1) suited for combusting the fuel, a hole (19) from the firebox to a post-combustion chamber (2), channels from the post-combustion chamber to the flue stack, a storage tank (9) surrounded by insulating walls (26) and having the firebox (1) adapted close to it so as to make the water space enclose the firebox at least partially, and the required piping, c h a r a c t e r i z e d in that the firebox (1) can function as both a boiler and an open fireplace, that the combustion air in the open fireplace use and in the boiler use are passed via essentially different paths, that the flue gases are directed to the flue stack in the open fireplace use and in the boiler use via essentially different paths, and that a pump and piping space (11), advantageously housing at least a circulation pump (12) and necessary means for connecting the storage tank to the central heating and water supply circuits, is adapted to inside the insulating walls (26).

2. A central heating unit as defined in claim 1, c h a r a c t e r i z e d in that in the open fireplace use the combustion air is essentially passed via an open firebox loading door (24) and in the boiler use the combustion air is essentially passed via at least one separate air intake hole (4, 6) .

3. A central heating unit as defined in claim 1 or 2, c h a r a c t e r i z e d in that between the firebox (1) and the flue stack, into the storage tank (9), are adapted channels (21, 23) incorporating a control means (22) suited for alternatively directing the flue gases via a shorter path (23) or a longer path (21) to the flue stack.

4. A central heating unit as defined in any of foregoing claims 1-3, c h a r a c t e r i z e d in that between the storage tank (9) and the firebox (1) is adapted at least one cavity (3, 5) , connected by at least one hole (4, 6) to the firebox (1) , via which hole or holes the combustion air preheated in the cavity or cavities (3, 5) is passed in boiler use.

5. A central heating unit as defined in any of foregoing claims 1-4, c h a r a c t e r i z e d in that said holes (4) are fitted from said cavity (3) to the ash pit (7) or close to the pit.

6. A central heating unit as defined in any of foregoing claims 1-5, c h a r a c t e r i z e d in that said holes

(6) are adapted close to the upper part of the firebox (1) .

7. A central heating unit as de ined in any of foregoing claims 1-6, c h a r a c t e r i z e d in that said post- combustion chamber (2) also serves as a baking oven.

8. A central heating unit as defined in any of foregoing claims 1-7, c h a r a c t e r i z e d in that said firebox (1) and said post-combustion chamber (2) are lined with bricks, a ceramic compound or equivalent material.