GB2044355A

GB2044355A - Improvements in or Relating to Transmission Arrangements for Exhaust Fans of Cooker Hoods

Info

Publication number: GB2044355A
Application number: GB7909124A
Authority: GB
Original assignee: YANG KUN CHIANG
Current assignee: YANG KUN CHIANG
Priority date: 1979-03-15
Filing date: 1979-03-15
Publication date: 1980-10-15

Abstract

At least one fan impeller 3 is driven by a motor 6 through a belt/pulley 7, 302, 602 or worm/gear 602'', 302a, b'', 8 transmission so that the fan speed is increased to provide a higher pressure difference for extracting or exhausting fumes or steam evolved during cooking. <IMAGE>

Description

SPECIFICATION Improvements in or Relating to Transmission Arrangements for Exhaust Fans of Range Hoods and the Like The present invention relates generally to transmission of exhaust fan in range hood and more particularly to the improvement of the speed of the motor driven fan impeller so that the pressure difference between the range and the fan is increased to better the efficiency of exhaustion.

Conventionally, the exhaustion of the fumes and steam evolved from cooking is usually effected by drawing through a strainer filter by a fan in a cooker or range hood arranged overhead.

The fan impeller is mounted directly on a motor shaft, so that speed of the fan may at best be about 1800 rpm for a motor of four-pole construction operated from a 11 OV 60 Hz source.

In practice, due to the existence of the copper loss, iron loss and mechanical loss etc., the motor speed actually achievable is reduced to 1 600 rpm and under. The pressure head depends directly on the motor speed, so that the lowering of the motor speed means results in a decrease in exhausting efficiency. Although the adoption of a two-pole motor may increase the speed to 3200 rpm, which is somewhat over the desired speed of 2000 rpm, a two-pole motor gives vibration and noise.

The main object of the present invention is to provide a range hood fan with a proper speed which is achieved by providing suitable belt/pulley transmission between the driving motor and the fan impeller. An appropriate ratio of pulley sizes is chosen to give a raise in the fan speed so that the exhaustion may be satisfactorily completed.

Another object of the present invention is to provide a range hood with the separation of motor and impeller, the height of hood may well be reduced to result in a save in space.

Still another object of the present invention is to provide a range hood with simplified construction with increased operation efficiency.

The invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a top view showing the layout of an exhaust fan on top of a range hood, constituting a first embodiment of the present invention; Figure 2 is a cross section taken along line A A in Figure 1; Figure 3 is a section taken along line B-B in Figure 1; Figure 4 is a top view showing a second embodiment; Figure 5 is a sectional view taken along line C-C in Figure 4; Figure 6 is a top view showing a third embodiment; Figure 7 is a top view showing a fourth embodiment; and Figure 8 is a sectional view taken along line D-D in Figure 7.

Referring to Figures 1,2 and 3, a fan impeller 3 is installed in the inner centre of a hood, over a strainer filter 2, a shaft 301 provided with a pulley 302. Two circular openings 401, 402 are disposed beside the impeller 3. One opening 401 is provided with a stack tube 5 which is mounted thereon by screws or other conventional means.

The other opening 402 is mounted with a motor 6 with its driving shaft 601 extending upward. A belt pulley 602 is provided thereon with a diameter greater than that of the driven pulley 302. A belt 7 is provided for transmission between the pulleys 302 and 602. A cover 8 is provided on top of the arrangement.

Since the diameter of driving pulley 602 is greater than that of the driven pulley 302, the speed of impeller 3 is greater than that of the motor 6 so that the pressure head thus achieved is improved and the fumes and steam evolved from cooking can be drawn and exhausted substantially completely through the stack 5.

If necessary, such as a result of limitation of building space, the positions of the motor 6 and the stack 5 can be easily interchanged.

By appropriate selection of pulley sizes, the speed of the fan impeller can be chosen as desired to improve the efficiency of exhaustion. A gear/chain system may be adopted instead of the pulley/belt system shown.

Another embodiment is showing in Figures 4 and 5, the motor 6' being located in the centre with its shaft 601 extended upwardly and with twin pulleys 602a' and 602b' disposed thereon.

At the sides of the motor 6', a pair of fan impellers 3a', 3b' with respective shafts 301 a', 301b' extended upwardly with pulleys 302a' and 302b' disposed thereon and connected with belts 7a', 7b' to the pulleys 602a',602b'. As in the case of the first embodiment, the pulley size ratio may be selected to give desired speeds of both fans and exhaust through exits (not shown) provided at both sides of the hood.

Figure 6 shows a modification of the embodiment of Figure 5, in which the motor is shifted aside to save space.

The embodiment shown in Figures 7 and 8 has a worm/gear transmission. On top of the shaft 601" of a motor 6", a worm gear 602" is provided to match with a worm rod 8 which is extended at both ends to drive a pair of worm gears 302a", 302,b" on top of driven shafts of impellers 3a", 3b". The impeller speed and the efficiency of exhaustion may thus be improved.

Claims

1. A transmission arrangement for an exhaust fan of a range hood, comprising a separate driving motor and at least one fan impeller, each having a pulley with a belt disposed there between, the pulley size ratio in the pulley/belt transmission system between the fan and the driving motor being chosen to provides a higher speed of the fan impeller to give a desired exhaustion efficiency.

2. An arrangement as claimed in claim 1,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in or Relating to Transmission Arrangements for Exhaust Fans of Range Hoods and the Like The present invention relates generally to transmission of exhaust fan in range hood and more particularly to the improvement of the speed of the motor driven fan impeller so that the pressure difference between the range and the fan is increased to better the efficiency of exhaustion. Conventionally, the exhaustion of the fumes and steam evolved from cooking is usually effected by drawing through a strainer filter by a fan in a cooker or range hood arranged overhead. The fan impeller is mounted directly on a motor shaft, so that speed of the fan may at best be about 1800 rpm for a motor of four-pole construction operated from a 11 OV 60 Hz source. In practice, due to the existence of the copper loss, iron loss and mechanical loss etc., the motor speed actually achievable is reduced to 1 600 rpm and under. The pressure head depends directly on the motor speed, so that the lowering of the motor speed means results in a decrease in exhausting efficiency. Although the adoption of a two-pole motor may increase the speed to 3200 rpm, which is somewhat over the desired speed of 2000 rpm, a two-pole motor gives vibration and noise. The main object of the present invention is to provide a range hood fan with a proper speed which is achieved by providing suitable belt/pulley transmission between the driving motor and the fan impeller. An appropriate ratio of pulley sizes is chosen to give a raise in the fan speed so that the exhaustion may be satisfactorily completed. Another object of the present invention is to provide a range hood with the separation of motor and impeller, the height of hood may well be reduced to result in a save in space. Still another object of the present invention is to provide a range hood with simplified construction with increased operation efficiency. The invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a top view showing the layout of an exhaust fan on top of a range hood, constituting a first embodiment of the present invention; Figure 2 is a cross section taken along line A A in Figure 1; Figure 3 is a section taken along line B-B in Figure 1; Figure 4 is a top view showing a second embodiment; Figure 5 is a sectional view taken along line C-C in Figure 4; Figure 6 is a top view showing a third embodiment; Figure 7 is a top view showing a fourth embodiment; and Figure 8 is a sectional view taken along line D-D in Figure 7. Referring to Figures 1,2 and 3, a fan impeller 3 is installed in the inner centre of a hood, over a strainer filter 2, a shaft 301 provided with a pulley 302. Two circular openings 401, 402 are disposed beside the impeller 3. One opening 401 is provided with a stack tube 5 which is mounted thereon by screws or other conventional means. The other opening 402 is mounted with a motor 6 with its driving shaft 601 extending upward. A belt pulley 602 is provided thereon with a diameter greater than that of the driven pulley 302. A belt 7 is provided for transmission between the pulleys 302 and 602. A cover 8 is provided on top of the arrangement. Since the diameter of driving pulley 602 is greater than that of the driven pulley 302, the speed of impeller 3 is greater than that of the motor 6 so that the pressure head thus achieved is improved and the fumes and steam evolved from cooking can be drawn and exhausted substantially completely through the stack 5. If necessary, such as a result of limitation of building space, the positions of the motor 6 and the stack 5 can be easily interchanged. By appropriate selection of pulley sizes, the speed of the fan impeller can be chosen as desired to improve the efficiency of exhaustion. A gear/chain system may be adopted instead of the pulley/belt system shown. Another embodiment is showing in Figures 4 and 5, the motor 6' being located in the centre with its shaft 601 extended upwardly and with twin pulleys 602a' and 602b' disposed thereon. At the sides of the motor 6', a pair of fan impellers 3a', 3b' with respective shafts 301 a', 301b' extended upwardly with pulleys 302a' and 302b' disposed thereon and connected with belts 7a', 7b' to the pulleys 602a',602b'. As in the case of the first embodiment, the pulley size ratio may be selected to give desired speeds of both fans and exhaust through exits (not shown) provided at both sides of the hood. Figure 6 shows a modification of the embodiment of Figure 5, in which the motor is shifted aside to save space. The embodiment shown in Figures 7 and 8 has a worm/gear transmission. On top of the shaft 601" of a motor 6", a worm gear 602" is provided to match with a worm rod 8 which is extended at both ends to drive a pair of worm gears 302a", 302,b" on top of driven shafts of impellers 3a", 3b". The impeller speed and the efficiency of exhaustion may thus be improved. Claims

2. An arrangement as claimed in claim 1, wherein the pulley/belt system is replaced by a gear/chain system.

3. A transmission arrangement for an exhaust fan of range hood, comprising a driving motor having a worm gear, a separate fan impeller with driven worm gear, a worm rod connecting the two worm gears to provide a transmission system whose gear sizes are chosen so as to improve the impeller speed.

4. An extractor system for a cooker or hob, comprising a drive motor, a fan impeller for extracting air from above the cooker or hob, and a transmission system arranged to cause the fan impeller to rotate at a higher speed than the motor.

5. A transmission arrangement or an extractor system, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

6. A cooker or hob including an arrangement or system as claimed in any one of the preceding claims.