SUCKING DEVICE

TECHNICAL FIELD

The invention refers to a sucking device suitable for vacuum appliances.

In the case of vacuum appliances featuring suction, such as vacuum cleaners for instance, used for both domestic and industrial purposes, it is known that the air is sucked up together with dirt through a suction pipe that communicates with the outside of the appliance body.

The sucked-up air is then filtered a first time before entering the housing area of the motor that turns a fan which generates air suction. This first filtering operation determines two effects at the same time: a first effect is that the dirt which has macroscopic dimensions and is conveyed in suspension by the sucked-up air is released inside a collection chamber provided for inside the body of the vacuum cleaner into which the suction pipe ends; a second effect is that the filtered air is conveyed towards the motor which is lapped by this and cooled during its operation.

After cooling the motor, the air is pushed outwards by the motor itself, through special grids or vents obtained in the body of the vacuum cleaner.

Before being expelled outwards, the air is filtered a second time and passes through a second filter with pre-defined porosity and finer, which is housed immediately downstream of the motor, so that even any of the smallest impurities still in suspension in the air after the first filtering operation and cooling are separated from this before it is returned to the environment.

The air flows exiting from the housing area of the motor after lapping and cooling this follow a prevalently turbulent pattern determined above all by the surface irregularities encountered by the flows during transit tangent to the walls of the motor and of the housing in which this is fitted.

STATE OF THE ART

This turbulence creates a drawback which is the need to use motors featuring greater powers than would be necessary if turbulent phenomena did not occur in the air flows sucked up and expelled outwards by the motor.

Because the power of a motor determines a cost in proportion to this, the higher the

power required, the higher the cost of the motor to be fitted on the vacuum appliances, such as for instance vacuum cleaners, which, therefore, undergo a substantial production and purchase cost increase.

PURPOSE OF THE INVENTION The technical aim of the invention is to upgrade the state of the art.

One object of the invention is to make a sucking device suitable for vacuum appliances that permits cancelling harmful sucked-up air turbulence phenomena. Another object of the invention is to make a sucking device suitable for vacuum appliances that permits curbing the production costs of vacuum appliances, and which for its operation uses relatively low-power motors.

According to one aspect of the invention it is provided a sucking device comprising: motor means arranged for sucking up air flows; filtering means of such air flows located downstream of said motor means, characterized in that said motor means and said filtering means are connected together with piping means designed to transform turbulent air flows into laminar air flows.

The sucking device, suitable for vacuum appliances therefore permits eliminating phenomena of turbulence in the sucked-up air and therefore considerably reducing the power required to operate the vacuum appliances and, therefore, cutting the production and purchase costs of the latter. BRIEF DESCRIPTION OF THE DRAWINGS.

Further characteristics and advantages will appear even more evident from the description of an embodiment of a sucking device suitable for vacuum appliances, illustrated indicatively by way of non limiting example, in the attached drawing in which the only Figure is a schematic view in transparency of a sucking device suitable for vacuum appliances.

FORMS OF EMBODIMENT OF THE INVENTION

With special reference to the Figure, a sucking device suitable for vacuum appliances, such as, for instance, a vacuum cleaner, has been designated as a whole by reference number 1. The sucking device 1 comprises a motor 2 which is housed in a seat 3 obtained in a vacuum appliance, not shown because known to the technician in the field, which

turns a fan 102 keyed on a shaft 103 motorised and turned by the motor 2 and which, when it turns, creates a vacuum that starts suction.

More precisely, the seat 3 in which the motor 2 is housed is defined in a shell 4 that wraps around it and which has an inlet 5 for the air sucked up by the fan 102 and an outlet 6 for the air expelled outwards.

Upstream of the inlet 5, a first filter 104 is fitted to filter the air flows sucked up by the fan 102 and which flow towards the motor 2 to cool this, separating the larger debris from the sucked-up air flows. The outlet 6 has a second filter 7 of pre-established porosity and finer than the first filter 104, so as to be able to trap even the smallest or microscopic dirt particles which have accidentally passed through the first filter 104, before the air used to cool the motor 2 is again introduced into the environment.

Between the seat 3 and the outlet 6 the shell 4 forms an extended pipe 8 of pre- established length which features one end 8A turned towards the motor 2 and an opposite end 8B that flows into the second filter 7 and which, afterwards, extends into the outlet 6.

The end 8A has a cross constriction 9 that reduces the transit cross section of the air exiting from the seat 3, after lapping and cooling the motor 2, and which is connected to this. The end 8B, on the other hand, has a section considerably widened compared to the end 8A, and consequently the pipe 8 is shaped like a sort of trumpet that gradually widens in the direction of the second filter 7.

As the Figure shows, the sucked-up air, indicated by the arrows "A", after lapping the motor 2 and cooling it, shows, immediately downstream of this, turbulence phenomena that are indicated by the arrows "T" which, approximately, show the pattern of numerous air threads 10 making up the air flow as a whole which is pushed by the action of the fan 102 and the motor 2 towards the outlet 6. Passing through the constriction 9, which, practically speaking, creates a sort of Venturi tube at the end 8A, the air, or more specifically the threads 10 making up the air flow, arrange themselves aligned and substantially parallel to each other, originating a laminar distribution indicated by the arrows "L" and transform into

laminar threads 11.

When the threads 10 cross the constriction 9, they increase their speed and then reduce this considerably as soon as they have transformed into threads 11, due to the gradual widening of the pipe 8 in the direction of the second filter 7, which forms an expansion chamber 208.

This reduction in speed gradually increases the pressure inside the expansion chamber 208 due to a considerable stagnation of the air; for this reason, the kinetic energy of the laminar threads 11 is partially recovered and transformed into an increase in the air pressure inside the expansion chamber 208 the pushing action of which is added to the pushing action of the fan 102 and the motor 2 to convey the air outwards, after crossing the second filter 7.

This increase in pressure, in helping to expel the air outwards through the second filter 7, in actual fact permits reducing the rated power of motor 2 required to both generate suction and expel the air outwards. Furthermore, for the purpose of improving as much as possible the flow of the laminar threads 11 along the pipe 8 while maintaining a laminar distribution, the internal walls 108 of this can undergo special smoothing and/or polishing, both during the building of pipe 8 and after its completion. According to a further form of embodiment of the sucking device 1, the internal walls 108 of the pipe 8 can be lined with sheets of material with strongly smoothed surfaces.