GB2210448A

GB2210448A - Cooker hood with oil extraction

Info

Publication number: GB2210448A
Application number: GB8723001A
Authority: GB
Inventors: Tiong Ee Ong
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-09-30
Filing date: 1987-09-30
Publication date: 1989-06-07
Anticipated expiration: 2007-09-30
Also published as: GB2210448B; GB8723001D0

Abstract

A cooker hood (10) has a power-driven oil-extracting unit 14(16) which is upstream of an active charcoal filter unit 18(20) which is itself upstream of a suction fan 24(26) so that air through the filter unit 18(20) has already had most of the oil removed so that the filter unit 18(20) does not become oil-contaminated. The oil-extracting 14(16) comprises high speed rotary mesh disks 52, 54 which whirl the air round and collect the centrifugally spun out oil in a reservoir 36(28) which can be emptied periodically. The filter unit 18(20) comprises two active charcoal filter elements (82, 84) in parallel, which can be bypassed by opening a valve (42, 44) if it is not desired to filter the air after the oil has been extracted. <IMAGE>

Description

Cooker Hood" This invention relates to a cooker hood In known cooker hoods, oil contaminates de-odorising filter units and renders them useless. Furthermore, oil-extraction is by means of passive filter meshes which are not very effective.

It is an object of the invention to enable these drawbacks to be overcome.

According to the invention there is provided a cooker hood comprising a power-driven centrifugal oil-extracting unit. a de-odorising filter unit downstream of the oil-extracting unit, and a power-driven fan for driving air through the oil-extracting unit and the filter unit.

The invention will be described by way of example with reference to the accompanying drawings, where: Fig. 1 is an underneath plan view of a cooker hood embodying the invention, that is to say, a view of the underside of the cooker hood; Fig. 2 is a section on line II-II of Fig. 1 Fig. 3 is a section on line III-III of Fig. 1 Fig 4 is a sectioned side elevation, partly broken away, of a power-driven centrifugal oil-extracting unit of the cooker hood; Fig. 5 is an illustration of a finger-guard disk of the oil-extracting unit; Fig. 6 illustrates one of a number of mesh disks of the oil-extracting unit; Fig. 7 illustrates an uppermost disk in the oil-extracting unit: Fig. 8 is a sectioned side elevation of part of the cooker hood, showing a de-odorising filter unit and a power-driven suction fan; and Fig. 9 illustrates a modified oil-extracting unit.

Referring to the drawings, the illustrated cooker hood 10 comprises a housing 12 in which there are arranged two power-driven centrifugal oil-extracting units 14,16, on opposite sides of the cooker hood 10, two de-odorising filter units 18,20, arranged inbetween the oil-extracting units 14 and 16 and divided one from the other as at 22, and two power-driven suction fans 24,26.

also arranged on the opposite sides of the cooker hood 10.

The cooker hood 10 also comprises two lights 28,30, one on each side of the cooker hood, and a further two smaller lights 32,34, also one on each side of the cooker hood.

Each oil-extracting unit 14,16, comprises an oil-reservoir 36,38 respectively, in the form of a glass cup which is removable for emptying oil therefrom.

Since the oil-extracting unit 14, filter unit 18 and fan 24 are respectively identical to the oil-extracting unit 16, filter unit 20 and fan 26, and since the cooker hood 10 is generally symmetrical on each side of the line 22, only one side of the cooker hood 10 will be described in detail, namely the left hand side in each of figs. 1,2 and 3.

The de-odorising filter unit 18(20) is downstream of the oil-extracting unit 14(16). The power-driven suction fan 24(26) is downstream of both the oil-extracting unit 14(16) and of the filter unit 18(20). Air is sucked into the cooker hood 10 by the suction fan 24(26), directly entering the oil-extracting unit 14(16) first of all from the cooking area (not shown), passing from the oil-extractor unit 14(16) via duct 40 to the filter unit 18(20) and passing from there to the suction fan 24(26). A selectively operable valve 42(44) is provided for selectively bypassing the filter unit 18(20) so that the air may, if desired, pass directly from the oil-extracting unit 14(16) to the suction fan 24(26), bypassing the filter 18(20). The interconnecting ducts are not shown, but are conventional.

Referring now more particularly to Figs. 4 to 7, the power-driven centrifugal oil-extracting unit 14 (which is identical to the corresponding oil-extracting unit 16) comprises a housing 45, a rotary electric motor 46 having a rotary output shaft 48 on which are mounted a lowermost disk 50 forming a finger guard disk, two wire mesh centrifuging disks 52 and 54 above the disk 50 and an uppermost disk 56. On the bottom end of shaft 48 is a locking cap or nut 57. Where the shaft 48 enters the housing 45 is a seal 59.

The finger guard disk 50 has radial mesh and is fitted with an annular edge ring 58 (not shown in figure 5).

The fume intake is beneath it, at 61.

The centrifuging disk 52, which is immediately above the figure guard disk 50, is of medium mesh. An inner annular portion of the disk 52, in the region of the shaft 48, is sandwiched between two strengthing rings 60,62. Whilst an inner portion 64 of the disk 52 is substantially flat, an outer portion 66 is downwardly dished, as shown in fig. 4, and is surrounded by an outer annular strengthing ring 68.

The centrifuging disk 54 is similar to the disk 52.

except that whereas disk 52 is of medium mesh, the disk 54 is of medium-to-fine mesh.

Each disk 52,54 is double-layered in the middle and single-layered at the side (where the peripheral speed is higher).

The uppermost disk 56 is a solid, slightly cupped, disk of molded reinforced thermoplastic material, without apertures, and is provided with fins 70 which are curved concavely in the direction of rotation (anti-clockwise in fig. 7).

A quiescent zone 72 for oil (and water) collection comprises a stationary annular mesh filter 74 through which there extend stationary radial fins (not shown) which serve, in use, to reduce swirling of the air in the zone 72 caused by the high speed rotation of disks 50,52.54 and 56. Beneath the zone 72 is an annular well 76 in which oil (and water) collects after removal from the air by the unit 14. Periodical removal of the cup 36 (fig 1) enables this oil (and water) to be drained off.

A port at 77 leads to filter unit 18.

Referring to fig. 8. the filter unit 18 comprises a housing 80 supporting internally two spaced apart active charcoal filter elements, namely, an upper active charcoal filter element 82 and a lower active charcoal filter element 84. The filter unit 18 has an inlet 86 connected to the oil-extracting unit 14. The inlet 86 leads directly to an upper air space 88, above filter element 82, and a lower air space 90, below filter element 84. Between the two filter elements 82,84 is a common filtered air space 92 which leads to the fan 24.

A wall 94 interconnects filter elements 82,84 and prevents air from the inlet 86 normally from passing directly into the air space 92. Hence, the air flow from inlet 86 is normally divided into two parallel air flows, one of which is into air space 88, thence through filter element 82 into air space 92, the other of which is into air space 90, then through filter element 84 into air space 92. Hence the two filter element 82,84 are effectively in parallel.

The valve 42, mentioned above, is mounted in wall 94 and can be opened if desired to allow much of the air from inlet 86 to pass directly into air space 92, bypassing the filter elements 82,84, if the air is not regarded as requiring deodorising, or if the filter elements 82,84 are clogged or in need of replacing The fan 24(26) has an electric motor 96 (fig. 2) driving fan blades 98.

The outlet from the fan 24 passes air upwardly out of the cooker hood 10 as shown.

In use, manually operable switches (not shown) may be selectively operated either to switch on oil-extracting unit 14 and fan 24 alone, to use the left hand side only of the cooker hood, or to switch on oil-extracting unit 16 and fan 26 alone, to use the right hand side of the cooker hood, or to switch on both oil-extracting units 14,16 together and fans 24,26 together, to use both sides of the cooker hood. Oil-laden and odour-laden air from cooking first of all enters the oil-extracting unit 14(16), where nearly all of the oil is extracted centrifugally by the high speed rotating disks. After most of the oil has been extracted, the air passes to the filter unit 18(20) wherein, assuming that the valve 42(44) is shut, the air passes through the filter elements so that the odour is extracted.Since the oil has already been extracted previously, the filter elements should have a long life and not become oil-contaminated. However, as mentioned previously, the filter unit 18(20) may be bypassed by opening the valve 42(44) if desired, in which case the life of the filter elements will be extended. However, the oil will still have been extracted by the oil-extractor unit 14(16).

The fan 24(26) is downstream of the oil-extracting 14(16) and the filter unit 18(20) so that it is a suction fan and any leakage will be into, rather than out of, the cooker hood. The fan 24(26) is required because the principal function of the oil-extracting unit 14(16) is oil-extraction, at which it is efficient, and not air flow production, at which it is not efficient. The fan 24(26) exhausts the air upwards.

The modified oil-extracting unit 100 of fig. 9 is without the disk 54 but is otherwise the same as unit 14.

In another modification, not shown, the two filter units change places respectively with the two oil-extracting units and two fans, so that the filter units are on the outside and the oil-extracting units and fans are on the inside of the cooker hood, with appropriate relocation of the lights and oil reservoirs and valves and so forth.

In another modification, not shown, there is just a single oil-extractor unit, single filter unit and single fan.

In another modification, not shown, the or each oil-extractor unit has a stationery finger guard fixed to the housing beneath the rotating disks, with apertures for the air too small to poke fingers particularly children's fingers - through.

Claims

1. A cooker hood comprising a power-driven centrifugal oil-extracting unit, a de-odorising filter unit downstream of the oil-extracting unit, and a power-driven fan for driving air through the oil-extracting unit and the filter unit.

2. A cooker hood as claimed in claim 1 wherein a bypass valve is provided for selectively bypassing the filter unit.

3. A cooker hood as claimed in claim 1 and 2 where the oil-extracting unit comprises a plurality of co-axially mounted rotatably driven mesh disks in a stack surrounded by an oil-collecting member.

4. A cooker hood as claimed in any preceding claim wherein the fan is a suction fan downstream of the oil-extracting unit and of the filter unit.

5. A cooker hood as claimed in any preceding claim wherein the filter unit comprises two filter elements arranged in parallel, upstream of a common filtered air space. and comprises passageways for dividing airflow from the oil-extracting unit into two airflows to flow through the respective filter elements.

6. A cooker hood as claimed in any preceding claim wherein the oil-extracting unit, the filter unit and the fan are arranged in mutually side-by-side positional relationship.

7. A cooker hood as claimed in any preceding claim wherein the oil-extracting unit has an oil reservoir which can be emptied.