GB2072830A - Stove grates - Google Patents

Abstract

A grate is composed of bars G each pivotally supported eccentrically to its centre of gravity. The pivotal mounting H, J may be such as to allow considerable free movement (such as a small pin in a large hole). Riddling of the grate is achieved by causing the bars to rock upon their pivotal mountings which may be done by causing tripping members M to impinge against the lower portions of the bars. Should the tilting action be obstructed by a small foreign object the grate bar may rise within the confines of the pivotal fixing arrangement, thereby increasing the gap between individual bars and permit the foreign matter to be released. <IMAGE>

Description

SPECIFICATION Improved grate for solid fuel fired equipment Related Field This invention may be applicable to any form of enclosed solid fuel burning equipment, stoves, boilers, air heating furnaces, and the like; although it may yield the greatest benefit when applied to equipment burning vegetable fuels such as wood, straw or peat for which it is primarily intended.

Background Information Fire grates generally comprise some form of grid to support burning fuel yet with gaps to permit ash to fall through and air to rise to aid combustion of the fire above. Frequent!y they are provided with some means of agitation to dislodge accumulated ash. Foreign matter too large to pass through the gaps remains above and has to be removed by some generally inconvenient means frequently necessitating emptying the firebox of fuel. Whilst this may present but an occasional minor problem with fossil fuels, with, for example, wood burning appliances the problem may be more frequent. Because of the nature of vegetable fuels and the ash formed by them the most suitable grate has very small openings and even small items of foreign matter such as nails may be retained above the grate.Moreover the smaller the openings, the greater the opportunity for the grate to clog with ash and consequently the more frequently riddling is required.

The Invention This invention comprises a grate composed of a number of bars each pivotally supported at the ends eccentrically to its centre of gravity. They may be of any sectional shape, solid or hollow, and set apart at such spacing as may be appropriate to the appliance, the fuel being burnt and the size, shape and form of bar itself. Being eccentrically supported they will naturally adopt an attitude with the centre of gravity below the axis of the pivotal mounting.

The grate is riddled by causing the bars to rock upon their pivotal axis. This is achieved by causing a tripping member or a multiplicity of tripping members to impinge on the sides of the grate bars at such a position as to be below the pivotal axis of the grate bars yet not so high as to prevent the tripping member passing beneath the grate bar once it has been tilted.

The pivotal mountings of the grate bars may be such as to allow considerable free upward movement, either by being in the lower end of a swinging link, pivotally attached to a fixed component; or by the device of making the two component parts of the pivot different dimensions such as a small pin in a large hole or slot. The effect of this arrangement is that should some foreign object obstruct the normal tilting operation of the grate bar under the action of the tripping member, the grate bar may rise and permit the foreign object to fall through the grate.

Since each grate bar is individually pivotally supported movement of fuel in the firebox due two burning may cause a small degree of agitation of the grate and tend to make it self-clearing.

The tripping member, or members, may take a variety of forms. Since it is only necessary for there to exist movement between tripping member and grate bar relative one with the other, the tripping member may be fixed and the grate constructed so that the grate bar can be moved past it. However, in the preferred arrangement and the folllowing descriptions the reverse is assumed, the grate is basically static and the tripping member or members are moved past the grate bars.

The system may comprise a siidingly mounted bar on which are a number of protusions to impinge on the grate bars. This sliding bar being situated beneath the grate bars and at an angle to them. Any reasonable angle may be employed although preferably it would be 900 or thereabouts. Each protusion may act as a tripping member.

Alternatively the system may utilise a finger or multiplicity of fingers as tripping members. The fingers being attached to a sliding carrier outside the grate area.

Alternatively it may take the form of an arm, with tripping protusion attached to the upper side of its outer end. The arm being caused to move in an arc beneath the grate so that the protusion trips each grate bar in turn.

Alternatively it may comprise a screw thread or similar helix or spiral form mounted beneath the grate bars and at an angle to them so that on rotation of the helix it engages with the lower portions of the grate bars including tilting action.

In any of the foregoing alternatives the tripping mechanism may be constructed either so that the centres between the invidual tripping members is similar to the centres between the individual grate bars in which case all grate bars will be rocked simultaneously or alternatively they may be spaced otherwise so that the grate bars are rocked in some form of sequence. Sequential operation having the benefit of reduced effort being required to riddle an appliance fitted with this invention.

Examples Figure 1 depicts part of a grate comprising grate bars A of hollow rectangular section material supported on pivot pins B carried in frame C at the ends of which are brackets D with a pair of holes through which slide bars E carrying fingers F.

Movement of bars E to and fro causes fingers F to impinge on the lower faces of grate bars A causing them to tilt, or if tilting action is impeded by solid obstruction they may rise and float within the limits imposed by the sections of A and B. After fingers F have passed beneath tilted bars A the grate bars A return to their normal position under gravity.

Figure 2 depicts part of grate utilising solid cast iron grate bars G the ends of which extend as stub axles H housed in large diameter holes J in beams K which are attached to the main structure of the appliance. Beneath the grate bars G runs the bar L carrying protrusions M. Bar L being in sliding bearings at each end. As bar L is moved to and fro the protusions M contact the grate bars G which tilt to permit the protrusions M to pass beneath them. Should normal movement be obstructed grate bars G may rise and float within the confines of holes J.

Claims (6)

1. A grate for a solid fuel fired heating appliance comprising a number of individual bars so positioned that the gap between any one of them and its neighbour or adjacent static components such as a frame or tie bar is suitable for the passage of air and/or ash and characterised in that each individual bar is pivotally supported at its end eccentrically to its centre of gravity.

2. A grate as claimed in Claim 1 in which the pivotal support is constructed with component parts of dissimilar dimensions so as to allow the bar an extent of free movement over and above the normal clearance required to permit rotation.

3. A grate as claimed in Claim 1 in which the pivotal support of the bar or bars is the lower end of a swinging link thereby allowing the bar an extent of free movement.

4. A grate as claimed in any preceding claim with adjacent to the grate bars a riddling bar on which are protusions or fingers so that relative movement between grate bars and protusions or fingers may cause the protusions or fingers to impinge on the lower portion of the grate bars to cause the grate bars to move on their mountings.

5. A grate as claimed in any preceding claim 1, 2 or 3 with adjacent to the grate bars a screw or helix so that there may exist engagement between the lower portion of the grate bars and the thread of the screw or helix, rotation of which may induce motion of the grate bars on their mountings.

6. A grate as claimed in any preceding claim 1, 2 or 3 with beneath the grate bars a swinging arm or arms carrying a protusion or multiplicity of protusions which on movement of the swinging arm may impinge on the lower portion of the grate bars causing them to move in their mountings.