GB2178523A

GB2178523A - Fire grates

Info

Publication number: GB2178523A
Application number: GB08615461A
Authority: GB
Inventors: John Staniland Burgis
Original assignee: AARROW DYNAMICS Ltd
Current assignee: AARROW DYNAMICS Ltd
Priority date: 1983-08-27
Filing date: 1986-06-25
Publication date: 1987-02-11
Also published as: GB8615461D0

Abstract

A grate comprises parallel firebars 3 of which at least alternate ones are movable along their length relative to adjacent ones, each bar having at its front a raised portion 9, which portions 9 together form a front retaining wall for the fuel bed. <IMAGE>

Description

SPECIFICATION Fire grates and stoves incorporating the same Where a grate is used for burning wood as a fuel it is preferably arranged so that an ash bed is created and the combustion air is supplied primarily over the fuel rather than through it upwards through the grate. It is also desirable to provide some means for assisting in riddling the ashes when this is desired or necessary. Previous proposals have involved the provision of separate units for achieving the above ends.

According to the invention a grate with a riddling action operated by an actuating arm or lever has the arm or lever so arranged that it also closes an air passage leading to a position where air is directed over the fuel bed.

According to a feature of the invention the grate comprises a number of fire bars reciprocable forwards and rearwards of the grate, each relative to a fixed or oppositely movable bar and each cooperating at one end with a rockable actuator extending across the grate, the actuator incorporating a flap which serves in one position to close the air passage referred to above. Preferably each of the movable bars has a hook-like portion which engages over an eccentric portion of the rockable actuator. Where alternate bars are movable in opposite directions the eccentric portions are arranged on opposite sides of the rocking axis, and in this case the actuator may be formed as a crank-shaft.

According to a further feature of the invention a grate of the kind described above, with or without the flap for closing the air passage, comprises a number of fire bars extending forwards and rearwards of the grate, and each bar has an upstanding front portion, such portions constituting between them a front retaining wall for the fuel bed.

The above and other features of the invention will be apparent from the following description of a stove incorporating a grate, reference being made to the accompanying drawings in which: Figure 1 is a side sectional view through a stove, Figure 2 is a front elevation of a number of fire bars in their operative position, Figure 3 is a side elevation of one of the two types of fire bar in Fig. 2 and Figure 4 is a side elevation of the other of the two types of fire bar.

The stove comprises a main body 1 composed of welded steel plate and closed at the front by a hinged door 2. Fire bars 3 and 4 are supported in a bracket 5 and 6 at the back of the stove and at the front they are carried by a rockable actuator 7 carried in bearings at the sides of the stove to rotate about the axis 8. Each bar has an upstanding front portion 9 so as to form a front wall to retain the fire bed in position. Combustion air is supplied through a shutter 10 in a front cover 11 of an ash pit 12. In the position shown, the actuator 7, which has an integral air control flap 13, obstructs the flow of air through an air passage 14 which is formed between the front wall of the stove and the lower parts of the actuator combined with the hook-like portions 15 of the fire bars 3.The combustion air is thus directed mainly through the main part of the grate formed by the fire bars and is thus suitable for burning fuels of the nature of coal or coke. The operation of the actuator 7 and the riddling action of the grate will be discussed later in relation to Figs. 2, 3 and 4.

The walls of the stove are protected by inserts 16 of fireclay which rest on brackets 5 and side rails 6 and are retained in position at the top by clips 17 and 18 which are simply slid into saddles 1 8a secured to the stove walls such as by welding. This forms an extremely inexpensive, convenient and quick method of securing the fireclay inserts in position compared with the usual method of cementing them. Moreover, in the case of the clips 17 on the back wall of the stove a bentout portion 1 7a is provided which supports the lower edge of a deflector plate 19, the sides of which rest on struck-out tabs 1 8a of the brackets 18. The deflector plate is thus very easily fitted and removed.

The stove has an outlet spigot 21 which is provided with a damper of unusual construction in that it has, in combination with a square section hole for the shaft, a pair of side bosses 22, one of which is shown, that engage the sides of the spigot. In this way the damper does not require positive location on the shaft endwise, and the shaft can thus be withdrawn so that the part of the flue which is attached to the spigot can be cleaned out through the inside of the stove with the deflector plate 19 removed.

Referring now to Figs. 2, 3 and 4 it will be seen that the fire bars 3 and 4 have side cheeks 23 at front and rear so as to locate against each other and the front ones ensure that the air passage 14 is adequately defined between them and the front wall of the stove.

The actuator 7 is in the form of a casting rockable about journals 24 (one of which is shown in Fig. 2) located in bearings in the side walls of the stove. The actuator has alternate upper and lower saddles 25 and 26 respectively with the fire bars 4 seated on the former and the fire bars 3 seated on the latter by means of hook-like portions 27 and 15 respectively. It will be seen that rocking of the actuator 7 will cause the alternate fire bars to slide in opposite directions to provide a very effective riddling action. The actuator 7 has two extreme positions, the one shown in Fig.

3 permitting an air flow to take place upwards between the front wall of the stove and the front side cheeks 23 of the fire bars. This is suitable for burning wood since air is then supplied over the top of the fire bed, and the other position shown in Fig. 4 is suitable for coal since air is then supplied mainly upwards through the fire bars. The air flow is indicated in each case by the arrows 28 and 29 respectively.

It will be observed that the journals 24 are not centrally arranged with respect to the upper and lower saddles 25 and 26, so that, when riddling is taking place, the bars attached to the saddles 26 will move further back and forth than the adjacent bars attached to the saddles 25. This improves the riddling action by imparting a rolling motion towards the front or back of the grate of small rounded particles which will then drop into the ash container.

Claims

1. A grate in which a riddling action is effected by movement of an actuating arm or lever characterised in that the arm or lever is so arranged that it also closes an air passage leading to a position where air is directed over the fuel bed.

2. A grate according to claim 1 characterised in that it comprises a number of fire bars reciprocable forwards and rearwards of the grate, each relative to a fixed or oppositely movable bar and each cooperating at one end with a rockable actuator extending across the grate, the actuator incorporating a flap which serves in one position to close the air passage.

3. A grate according to claim 1 having an operating crankshaft for the movable bars of the grate characterised in that in at least one position of the crankshaft the flow of air upwards at the front of the grate and over the fuel bed is inhibited in favour of air flowing upward through the grate.

3. A grate according to claim 2 characterised in that each of the movable bars has a hook-like portion which engages over an eccentric portion of the rockable actuator.

4. A grate according to one of the preceding claims, with or without the flap for closing the air passage, characterised in that it comprises a number of fire bars extending forwards and rearwards of the grate, and that each bar has an upstanding front portion, such front portions constituting between them a front retaining wall for the fuel bed.

5. A stove incorporating a grate according to any one of the preceding claims.

CLAIMS Amendments to the claims have been filed, and have the following effect: Claims 1 above have been deleted or textually amended.

New or textually amended claims have been filed as follows:

1. A grate, especially for a dual fuel solid fuel stove, comprising a number of parallel fire bars of which at least alternate ones are movable along their length relative to adjacent ones, each fire bar having at the front a raised end, characterised in that the raised ends together form a front retaining wall for the fuel bed.

2. A grate according to claim 1 having an operating crankshaft for the movable bars of the grate characterised in that in at least one position of the crankshaft the flow of air upwards through the grate is inhibited in favour of air flowing upwards at the front of the grate and over the fuel bed.