GB2084313A

GB2084313A - Improvements in or relating to feed devices

Info

Publication number: GB2084313A
Application number: GB8030355A
Authority: GB
Original assignee: Coal Industry Patents Ltd
Current assignee: Coal Industry Patents Ltd
Priority date: 1980-09-19
Filing date: 1980-09-19
Publication date: 1982-04-07
Also published as: EP0048547A3; EP0048547A2

Abstract

A feed device (1) for solid fuel domestic appliances comprises a hopper (2) with downwardly inclined sides (3) defining a discharge slot (4) beneath which is located a flat plate (6) in spaced relation thereto. The plate (6) is mounted on a central pivot (7) and is movable thereabout by a suitable low power low speed drive. A spreader device comprising two series of inclined spaced apart metal strips (8) is located below the plate (6). Fuel held within the hopper (2) flows out onto the plate (6) and assumes a natural angle of repose when the plate (6) is horizontal. Upon small angular movement of the plate (6), fuel is caused to flow off the plate (6) which in use is disposed evenly over a fire bed by the spreader device. <IMAGE>

Description

1

GB 2 084 313 A 1

SPECIFICATION 65

Improvements in or Relating to Feed Devices

This invention concerns improvements in or relating to feed devices for use particularly 5 although not exclusively in solid fuel domestic 70 combustion appliances.

One of the needs especially in modern times is for a means of automatically feeding solid fuel onto the firebed of a solid fuel burning appliances, 10 thereby obviating the need for manual operation. 75

It is desirable to provide a system giving incremental feed to maintain the correct combustion rate and thus output.

Various suggestions have been made in an 15 endeavour to meet this need. For example rotary 80 valves or sliding plates have been proposed but these suffer from the disadvantage of high power consumption for the drive motors and they both involve a shearing or crushing action on the fuel. 20 Particularly for the domestic market, low power, 85 low cost mechanisms are required.

One of our earlier inventions described and claimed in GBPA 2 011 065 is directed to the use of a paddle wheel rotor which found successful 25 application when used for singles size coal as it 90 did not involve shearing of the fuel. However it provided a batch feed and attempts to modify this system to give an incremental feed were unsuccessful. Also for larger sized fuel, for 30 example doubles, the dimensions of the paddie 95 wheel would become too great to accommodate within the confines of a domestic appliance.

An object of the invention is therefore to provide an improved feed device.

35 Accordingly the invention provides a feed 100

device including in combination a hopper with at least two inclined bounding walls leading at relatively lower ends thereof to a discharge outlet, a plate disposed beneath the outlet at such a 40 distance therefrom as to allow in use material 105 from the hopper to assume a natural angle of repose, and means for moving the plate such that in use upon movement of the plate material is caused to discharge from the plate.

45 The plate is preferably flat or substantially flat 110 and is wider than the discharge outlet of the hopper.

The plate is conveniently mounted on a central pivot, movement about the pivot in either 50 direction in use occasioning the discharge of 115 material from the plate.

The means for moving the plate may advantageously be a small slow speed motor, conveniently electrical, which is coupled via a 55 crank arrangement to the pivot of the plate, 120

thereby in use giving a smaller angular movement of the plate. The degree of angular movement is conveniently of the order of 2 0 to 7 °.

Alternatively, the means for moving the plate 60 comprises a vibrator for transmitting intermittent 125 vibrations to the plate thereby upsetting in use the natural angle of repose of material resting on the plate.

The angular orientation of the hopper walls is advantageously of the order of 35° to 45° to the horizontal.

Operation of this device will give an incremental feed of material from the hopper. However, in the case of a coal burning appliance, it is desirable in some cases to distribute the fed material evenly onto a firebed. This cannot be acheived by the device, which will discharge the coal onto the firebed into two piles. To avoid this problem, where necessary, the device may also include a spreader device located below the plate. Conveniently the spreader device comprises two series of spaced apart metal strips, each series being for location adjacent one edge of the plate at an angle of about 25° to the horizontal such that a proportion of the material discharged from the plate is deflected below the plate.

The present invention is preferably directed to a feed device for feeding solid fuel to a combustion appliance and a further aspect of the invention is directed to a solid fuel combustion appliance incorporating such a feed device.

By way of example, one form of feed device according to the invention is described below with reference to the accompanying drawings in which:—

Figure 1 diagrammatically illustrates the invention in cross section; and

Figure 2 is a plan view along the line A—A of Figure 1.

Referring to the drawings, a feed device 1 comprises a hopper 2 having at least two lower sides 3 inclined downwards a discharge outlet in the form of a slot 4. The angle of inclination of the sides 3 is in this example 40° as a preference. It has been found by experiment that the width of the slot 4 should be of the order of 120 mm in order to feed doubles size coal efficiently, there being no upper limit.

A flat plate 6 is located directly beneath the slot 4 at a minimum distance, in this embodiment of 95 mm, and is mounted at its centre on a pivot 7. The minimum width of the plate 6 in this example is 256 mm. The combination of these dimensions ensures that in use material, for example solid fuel, in the hopper 2 flows out of slot 4 and assumes a natural angle of repose on the plate 6 when in a horizontal position at which no discharge therefrom occurs.

A low power slow speed electric motor (not shown) is provided and is coupled to the pivot 7 to impart a slow oscillatory motion to the plate 6. An angular movement either side of the horizontal neutral position of up to 7° has been found to give a discharge of material, for example fuel,

from the plate in increments. It has also been determined by experiment that a motor speed of less than 1 rpm and an angular movement in either direction of 6° gives a good result. At motor speeds of between 1 rpm and 5 rpm and an angle 3°, good results have also been obtained.

Mounted below the plate 6 is a spreader device comprising two series of spaced apart metal strips 8. Each series of strips slopes at an angle of about 20° to the horizontal towards the centre of

2

GB 2 084 313 A 2

the device, their lower ends being located adjacent one edge of plate 6. In this instance, the strips are 25 mm wide and spaced 40 mm apart. The distance between the lower ends of the series 5 of strips is 330 mm and the vertical distance from the plate 6, when horizontal, to the lower end of the strips 8 is 92 mm. As the material discharges from the plate 6 it falls onto one of the series of strips 8. A proportion of the material is deflected 10 by the strips to below the plate 6, and the rest falls through to spaces between the strips 8, thus producing an even bed of material.

The feed device of the present invention is particularly applicable to a domestic combustion 15 appliance in which an incremental feed of solid fuel is required. The intermittent or continuous actuation of the motor to move the plate provides the desired feed characteristic at low cost and automatically and the spreader device provides an 20 even firebed. The dimensions given herein are especially suitable for feeding doubles size coal, but may be altered according to the material to be fed.

Claims

Claims

25 1. A feed device including in combination a hopper with at least two inclined bounding walls leading at relatively lower ends thereof to a discharge outlet, and a plate disposed beneath the outlet at such a distance therefrom as to allow 30 in use material from the hopper to assume a natural angle of repose, and means for moving the plates such that in use upon movement of the plate material is caused to discharge from the plate.
2. A feed device according to claim 1 in which

35 the plate is fiat or substantially flat and is wider than the discharge outlet of the hopper.
3. A feed device according to claim 1 or 2 in which the plate is mounted on a central pivot.
4. A feed device according to any one of the

40 preceding claims in which the means of moving the plate is a low speed low power electrical motor.
5. A feed device according to claim 4 as dependent on claim 3 in which the motor is

45 coupled to the pivot to provide bi-directional angular movement to the plate.
6. The feed device according to claim 5 in which the angular movement in either direction is in the range 2° to 7°.

50
7. A feed device according to any one of the preceding claims in which the angular inclination of the walls is in the range 35° to 45°.
8. A feed device according to any one of the preceding claims and further including a spreader

55 device located below the plate.
9. A feed device according to claim 8, in which the spreader device comprises two series of spaced apart metal strips, each series being for location adjacent one edge of the plate at an

60 angle of about 25° to the horizontal such that a proportion of the material discharged from the plate is deflected below the plate.
10. A feed device substantially as hereinbefore described with reference to, the accompanying

65 drawing.
11. A solid fuel combustion appliance including a feed device according to any one of the preceding claims.

Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 19S2. Published by the Patent Office, 25 Southampton Buildings, London, WC2A 1 AY, from which copies may be obtained.