GB2073874A

GB2073874A - Hot-water boiler

Info

Publication number: GB2073874A
Application number: GB8011939A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-04-10
Filing date: 1980-04-10
Publication date: 1981-10-21
Also published as: GB2073874B

Abstract

A hot-water boiler comprises a boiler body 2 having a feed-water opening 3 and a hot water outlet 7, a water storage tank 5 and a combustion chamber 15 in an upper and a lower portion respectively of the boiler body. Fire-tubes 18 are connected between the top of the combustion chamber and a smoke box 19 which is formed at the lower end of a main flue 20. The main flue passes through the water storage tank and the upper end of the upper portion of the boiler body. The main flue is provided with a first damper 52 which controls the amount of ventilation of the flue. An auxiliary flue 54 having a smaller diameter than the main flue 20, passes through the boiler body from the combustion chamber. The auxiliary flue is provided with a second damper 55. <IMAGE>

Description

SPECIFICATION Hot-water boiler This invention relates to a hot water boiler, and has particular reference to a fire-tube boiler.

It has been known to use a hot-water boiler as shown in Fig. 1 for supplying domestic hot water, e.g. to a bathroom and a kitchen. Fig.

1 shows a sectional view of a known hotwater boiler, in which the water is fed into a water storage tank 5 formed inside a boiler body 2 through a feed pipe 4 connected to a feed-water opening 3 in a side wall 2b of the cylindrical boiler body 2, Furthermore, a cistern 6 having a float valve is provided at one end of the feed pipe 4. The boiler body 2 has a hot water supply outlet 7 for feeding hot water to, for example, a bathroom and a kitchen. The water is heated in the storage tank 5 in the boiler body 2. The boiler body 2 has a drain valve 8 and an expansion tube for pressure control 9 in the conventional manner (though the detailed explanation has been omitted).

Furthermore, the lower portion of the boiler body 2 has an ash-receiving peart 11, which has an ash removal opening 10. The upper end of the ash-receiving part 11 has a flange 12, on which a grate 1 3 is positioned. On the fire grate 13, there is a combustion chamber 1 5 which is defined by an upper wall 1 5a and side walls 1 sub. The bottom of the lower portion of the storage tank 5 is defined by the side walls 1 sub. A fire door 1 6 is provided, in the side wall 1 Sb of the combustion chamber 1 5 and the side wall 2b of the boiler body 2 corresponding to the side wall 1 Sb respectively, so that fuel such as wood, scrap paper, combustible rubbish, may be thrown through the fire door 1 6 into the combustion chamber.

Furthermore, the upper wall 1 spa is perforated to form a plurality of passages 1 7, into which are inserted fire-tubes 1 8 in water-tight manner. A smoke box 1 9 is connected to the end of the fire-tubes furthest from the passages 1 7. The smoke box is formed from the lower portion of a flue 20. The flue 20 passes through an upper wall 2a of the boiler body 2. Therefore, air and combustion gas generated in the combustion chamber are vented to the outside by passing through the ventilation flue, the combustion chamber 15, the fire- tubes 18, the smoke box 1 9 and the flue 20.

Accordingly, this boiler provides energy savings by the effective use of the fuel and increased heat transfer area from the fuel combustion in the combustion chamber 1 5 to the large volume of water stored in the water storage tank 5 inside the boiler body 2 and the use of fuel such as scrap paper and combustible rubbish.

In this boiler, however, when the fuel such as fire wood, scrap paper, wood and combustible rubbish has a poor calorific value, or combustion is weals untie the burning-out of the fuel, and after the burning-out of the fuel, the outside air flows into the ventilation flue consisting of the combustion chamber 15, the fire-tube 1 8, the smoke box 1 9 and the flue 20. Thus, more fire-tubes must be used in order to increase the transfer effect. Therefore, a disadvantage of this boiler is that the boiler is further cooled down, because the number of fire-tubes has been increased.A further disadvantage is that there is incomplete fuel combustion, because the fuel combustion for producing heat is impossible when the flue 20 is closed before the burning-out of the fuel in order to prevent cooling.

According to the invention, a hot-water boiler comprises a boiler body having an opening for feed-water and an outlet for hot water, a water storage tank and a combustion chamber in an upper and lower portion respectively of the boiler body, a plurality of fire-tubes connected at their lower ends to the combustion chamber and at their upper ends to a smoke box formed at the lower end of a main flue which passes through the water storage tank and the upper end of the upper portion of the boiler body, the main flue being provided with a first damper which enables the amount of ventilation of the flue to be controlled, and an auxiliary flue having a smaller diameter than the main flue, which passes through the boiler body from the combustion chamber and is provided with a second damper.

The invention can provide a hot-water boiler in which the heat consumption of the boiler is a minimum. The invention can provide a boiler in which it is possible to have combustion for producing heat and the complete combustion of the fuel using combustible rubbish, even if the fuel has a poor calorific value, heat generation until the burning-out of the fuel is low, and low or no quantity of heat in fuels after burning-out in the combustion chamber having a large heat transfer area when the amount of water to be stored is abundant.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 2 is a sectional view of a hot-water boiler according to the invention; and Figure 3 is a sectional view o, a second embodiment of the hot-water boiler shown in Fig. 2.

Fig. 2 shows a hot-water boiler 51. The same numbers are used in Fig. 1 for corresponding parts, and detailed explanations are omitted.

A first damper 52 is positioned in the main flue 20, which passes through the upper wall 2a of the boiler body 2 in a direction away from the smoke box 1 9 or the flue 20. It is possible to open or close the flue by means of the damper 52.

An auxiliary flue 24, which is connected through the outside of the boiler body to the combustion chamber 15, extends upwards along the side wall 2b of the boiler body 2.

Tht auxiliary flue 54 passes through the side wall 2b of the boiler body 2 and the outside wall 2b of the combustion chamber 1 5. A second damper 55 is positioned near the upper end of the auxiliary flue 54, so the flue can be closed or opened easily. The auxiliary flue 54 has a smaller diameter than the flue 20.

When the hot-water boiler 51 is stoked, the fuel containing the combustible rubbish etc.

can be initially burnt with the first damper 52 open and the second damper 55 closed (or opened). The ventilation is via the combustion chamber 15, the fire-tubes 1 8, the smoke box 1 9 and the flue 20. During the period from when the amount of fuel decreases until the fuel is completely burnt, the second damper is open, whilst the first damper is closed. The ventilation is then via the combustion chamber 15, auxiliary fire-tubes (not shown), and the auxiliary flue 54. The ventilation path through the plurality of fire-tubes 18 is closed. Furthermore, when the combustion is ended, the second damper 55 is closed.

Therefore, the amount of heat lost from the fire-tubes and the main flue can be controlled to a minimum, when the fuel has a poor calorific value or the combustion is weak during the period until the fuel is completely burnt, and after the burning-out of the fuel.

Furthermore, the combustion of the fuel for heating purposes, the complete use of the fuel, and the use of combustible rubbish as fuel are possible. Various kinds of effects are also possible, such as energy savings and the prevention of environmental contamination.

It is possible for the auxiliary flue 54 to be attached to the side of the flue 20. In this way, the air from the combustion chamber 1 5 can only be vented through the auxiliary flue.

Fig. 3 shows a modified boiler, in which the grate 1 3 is not attached to the flange 1 2 as shown in Figs. 1 and 2. The combustion chamber is of a different shape to the chamber shown in Figs. 1 and 2. The chamber wall is not curved as shown in Figs. 1 and 2. In this way, the construction is simplified, and damage of the boiler body owing to overheating is reduced. The modified boiler is provided with a main flue and an auxiliary flue, though these are not shown in Fig. 3.

The arrangement of the flues, plus the positioning of the dampers in the flues, is the same as shown in Fig. 2. The same numbers are used as in Fig. 2, and detailed explanations are therefore omitted.

Claims

1. A hot-water boiler comprising a boiler body having an opening for feed-water and an outlet for hot water, a water storage tank and a combustion chamber in an upper and lower portion respectively of the boiler body, a plurality of fire-tubes connected at their lower ends to the combustion chamber and at their upper ends to a smoke box formed at the lower end of a main flue which passes through the water storage tank and the upper end of the upper portion of the boiler body, the main flue being provided with a first damper which enables the amount of ventilation of the flue to be controlled and an auxiliary flue, having a smaller diameter than the main flue, which passes through the boiler body from the combustion chamber and is provided with a second damper.

2. A hot-water boiler according to claim 1, wherein the auxiliary flue is attached to the side of the flue.

3. A hot-water boiler according to either of the preceding claims, wherein the surface of the boiler body houses a flange and a grating inside the combustion chamber, to remove the attached portion of the flange and grating with the boiler body.

4. A hot-water boiler substantially as herein described with reference to Fig. 2 or 3.