A LOW NOISE ASPIRATOR AND/OR VENTILATOR DEVICE The present invention concerns a low noise aspirator and/or ventilator device that may be used specially for domestic, industrial and sanitary vacuum cleaners, warm air driers and convectors in general, hair driers, high-pressure water cleaning machines, compressors, aspiration pumps and other.

A problem concerning this kind of electric household appliances and machines consists in the noise, which is particularly bothersome for the household appliances so as to limit their possibility of use.

This problem is caused substantially by the use of electric brush motors, running at a very high speed-about 20,000 rpm-that allow to obtain a suitable aspiration, ventilation or compression power but are very noisy due to the brushes rubbing on the collector.

Low speed electric motors having a low noise are known, such as inductive motors which usually have a speed of rotation of 1,400 or 2,800 rpm. These motors, however, are not used in the known aspirator and ventilator devices, because their low speed of rotation would not yield the desired aspirator or ventilator power.

It is the aim of the present invention to realize a low noise aspirator and/or ventilator device that may be applied to a plurality of household appliances or machines for industrial purpose, such as vacuum cleaners, warm air driers, high-pressure water cleaning machines, compressors and pumps, as well as to multifunctional machines like, for example, a water cleaning machine also comprising an air aspirator.

The aim set forth is reached by means of the present invention, consisting of an aspirator and/or ventilator device, comprising an electric motor, operating means and connecting means between said motor and said operating means, characterized in that said electric motor is a low-speed motor and said connecting means comprise a speed multiplier transmission.

Said low-speed motor is advantageously an inductive motor, having a speed of rotation of 1400 or 2800 rpm. As an alternative, it may be also a collector motor, or a Hall-effect motor.

Said transmission advantageously comprises a couple of wheels or belt pulleys, connected with means adapted for transmitting the motion.

The advantage obtained by means of the present invention consists in that, due to the use of said low-speed motor and of said speed

multiplier, the device result particularly noiseless, still having a suitable aspiration and/or ventilation efficiency.

The present invention will be described more in detail hereinbelow, relating to the enclosed drawings showing some preferred embodiments.

Figure 1 shows a schematic lateral and partially sectional view of an aspirator and/or ventilator device, realized according to the present invention.

Figure 2 shows a schematic sectional view of a low noise vacuum cleaner, comprising a device according to figure 1.

Figure 3 shows the essential scheme of a high-pressure water cleaning machine, also comprising an air aspirator, realized with a device according to the present invention.

Relating to the details shown in the figures, the aspirator and/or ventilator device according to the present invention essentially comprises an electric motor 1, connected to operating means 2 by means of a speed multiplier transmission 3, having a velocity ratio higher than 1.

The electric motor 1 is a low-speed motor, usually with a speed of rotation of 1400 or 2800 rpm, and, advantageously, it is an inductive motor.

The operating means 2 are adapted to treat air, water or fluids in general. In the shown embodiment, said means essentially comprise a centrifugal, axial-inlet air impeller 4, and a diffuser 5.

The transmission 3, according to the shown embodiment, is a belt transmission that comprises a first shaft 6 connected to the motor 1, a second shaft 7 on which the impeller 4 is keyed, a couple of belt pulleys 8a and 8b, respectively keyed on the shaft 6 and on the shaft 7, and a transmission belt 9 connecting said pulleys.

The belt 9 transmits the motion between said two pulleys 8a and 8b without slipping on them. For this purpose, a multi-trapezoidal section belt may advantageously be used, like the known Poly-V (g belt; however, other kinds of belts may also be used, such as circular section belts.

If the device is used as an air aspirator and the electric motor 1 is of inductive type, the velocity ratio is advantageously about 10: 1, even if it shall be determined according to the motor used, to the features of the operating means and to the aspiration or ventilation power required.

The transmission 3 may be realized in other ways, according to the known art, for example by means of gears, mechanical contact pulleys or magnetic contact pulleys.

Further known elements, like supports and bearings for shafts 6 and 7, are not shown.

A practical application of the present invention for obtaining a low noise vacuum cleaner is shown in figure 2.

The vacuum cleaner essentially comprises a cylindrical drum 10, housing the motor 1, the operating means 2, including the impeller 4 and the diffuser 5, and the transmission 3.

The drum 10 comprises, on its external surface, an aspiration pipe union 11 for the connection of means of use like a flexible or a rigid pipe, joints and other. Advantageously, said pipe union 11 is placed on the lateral surface of the drum 10.

The pipe union 11 is connected to said impeller 4 by means of a closed duct 12, internal to said drum 10. At least one filter 13 is provided along said duct 12.

The discharge of said diffuser 5 is connected to a pipe 14, ending inside a layer of sound absorbing material 15, permeable to air, provided at the bottom of the drum 10.

The vacuum cleaner further comprises an air discharge outlet 16.

Advantageously, air heating means are connected to the vacuum cleaner, such as an electric resistance 17, placed in the air outlet 16.

Said heating means may further comprise a thermostat, regulation controls like a timer and other similar devices commonly used, for example, on stoves or warm air convectors.

In different embodiments, said heating means may be placed differently, according to the needs, or they may be directly connected to the aspirator and/or ventilator device.

The electric resistance 17, for example, may be placed at the discharge of the diffuser 5 or it may be housed in a discharge pipe external to the device.

Figure 3 shows another possible application of the present invention, for obtaining a high-pressure water cleaning machine, that may be used also as a vacuum cleaner or air aspirator, thanks to the device according to the present invention.

Said machine essentially comprises an aspirator and/or ventilator device as described above, and a high pressure pump 20, mechanically connected to the opposite end of the shaft 6 of the electric motor 1. Said pump 20 is usually a positive-displacement pump.

The working of the device according to the present invention is the following.

Relating to the details shown in figure 1, the electric motor 1 drive the impeller 4 by means of the transmission 3. The impeller 4 sucks air from its central portion and leads it into the diffuser 5 with a centrifugal motion.

As the motor 1 is an inductive low-speed motor, the noise produced by said device is particularly low.

However, due to the velocity ratio of about 10: 1 between the pulleys 8a and 8b, the impeller 4 rotates at a high speed, such as to supply the required aspiration or ventilation power.

The vacuum cleaner shown in figure 2 works as follows.

The impeller 4 sucks an air flow from the pipe union 11 through the duct 12, and discharges it into said diffuser 5. Dust and solid particles transported by said air flow are filtered by the filter 13, placed upstream of the impeller.

At the discharge of the diffuser 5, the air flow has a rather high speed, due to the quick rotation of the impeller 4. By means of a pipe 14, the discharge of said diffuser 5 is led through the layer of sound absorbing material 15, where it slows down and distributes through a large passage section. Thus, the working noise of the machine is further reduced, reducing rustle and other aerodynamic noises due to the turbulent flow in the drum 10.

Finally, the air flows from the sound absorbing layer 15 into the drum 10, and is released outside through the outlet 16.

The duct 12 also allows to keep the aspiration air flow separated from the discharge air flow, thus improving the general efficiency of the vacuum cleaner.

The air heating means, among which the electric resistance 17, allow the use of said vacuum cleaner also as a warm air convector.

Furthermore, the low noise obtained by means of the device according to the present invention allows a continuous working, without any particular inconvenience, also for domestic or night heating.

The motor used is also suitable for pumps, compressors or other machines working with fluids, and therefore the invention enables the realization of multifunctional machines, like the high-pressure water cleaning machine shown in figure 3, that may be used also as a vacuum cleaner or an air aspirator in general, with the advantage of a single machine suitable for different uses, in addition to the low working noise.

It is obvious that the machine may be provided with devices adapted to choose its use as a water cleaning machine or a vacuum cleaner, like electrical or mechanical selectors of known type.

A further possibility, not shown, is to use a device according to the present invention for realizing a professional hair drier, with a main body inside which the aspirator and ventilator device is housed, and a flexible pipe of suitable length. Said pipe advantageously ends with a handle, inside which the means for air heating and its regulation controls are inserted.

Finally, it is clear that the aforesaid examples of application o the invention are not limitative, as the same advantages will be obtained in a number of other domestic or professional machines.