|Title of Invention||
|Abstract||A muffler is incorporated into an electric motor housing air flow across the motor and to reduce noise escaping from the housing. The muffler includes a cone adapted to be mounted adjacent the exhaust side of the motor fan. The muffler further includes an exhaust passageway comprising at least 270.degree.in turns before final exhaustion.|
|Full Text||COMPLETE AFTER PROVISIONAL "EFT ON 20-5-2004
THE PATENTS ACT 1970 (39 of 1970)
As amended by the Patents (Amendment) Act, 2002
(See Section 10; Rule 13)
20 MAY 2004
Koninklijke Philips Electronics NV
having its place of business at
1, Groenewoudseweg, 5621 BA Eindhoven,
The Netherlands, a Company incorporated in Netherlands
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:
FIELD OF INVENTION
This invention relates to mixer grinder
A household mixer grinder comprises an electric motor assembly
located within a housing. The motor assembly includes a radial fan disposed within the motor assembly mounting bracket and fitted towards the upper end of the motor shaft. The radial fan comprises a disc provided with a plurality of blades spaced radially and mounted on the lower surface thereof. During operation of the mixer grinder the radial fan rotates with the motor shaft and atmospheric air entering the housing through the air inlets at the bottom thereof is swept over the motor assembly and thrown out through the air outlets at the upper side of the housing thereby taking away the heat generated within the housing due to the operation of the motor and
cooling the motor assembly. Noise generated within the housing especially during high speed operation of the mixer grinder due to turbulence in the air flow and due to aero dynamics i.e. noise generated by the fan blades while cutting the air and also due to mechanical and magnetic imbalances of the motor assembly is directly transmitted to the atmosphere through the air outlets . This makes operation of the mixer grinder very noisy.
OBJECTS OF THE INVENTION
An object of the invention is to provide a mixer grinder which operates at reduced noise level.
Another object of the invention is to provide a mixer grinder
which is simple in construction and easy to operate.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention there is provided a mixer grinder comprising a motor assembly located within a housing provided with air inlets and air outlets at the bottom and at the upper side thereof, respectively, the motor assembly comprising an axial fan fitted at the lower end of the motor shaft and comprising a hub provided with a plurality of blades spaced radially and a silencer cum air guide sleeve disposed over the motor assembly extending from the lower end up to the upper end of the motor shaft, the upper portion of the silencer cum guide sleeve comprising an airflow interrupter.
According to an embodiment of the invention, the sleeve is of two piece construction comprising a lower portion and an upper portion.
According to an embodiment of the invention the airflow interrupter comprises a disc provided across the upper end of the silencer cum guide sleeve above the mounting bracket of the motor assembly, the disc being provided with spaced openings at the periphery thereof associated with arch like airflow obstructing baffles.
According to an embodiment of the invention, the mixer grinder is L-shaped.
The invention is described herein below with reference to Fig 1 of the drawings accompanying the provisional specification and Fig 1A of the drawings accompanying this specification. In the drawings accompanying this specification the sole Fig 1A is an isometric view of the upper portion of the mixer grinder of Fig 1 of the provisional specification. Referring to Figs 1 and 1A, the mixer grinder 1 is L-shaped and comprises a housing 2 provided with air inlets 3 and air outlets 4
at the bottom and upper side thereof, respectively (Fig 1). The legs of
the mixer grinder are marked 5. The motor assembly of the mixer grinder is
marked 6. The motor assembly includes an axial fan marked 7 fitted at the
lower end 8 of the motor shaft 9 and comprising a hub 10 provided with
a plurality of blades 11 spaced radially. 12 is a silencer cum air guide
sleeve disposed over the motor assembly extending from the lower end up to
the upper end of the motor shaft defining a clearance 12a with the motor
assembly. The sleeve is of two piece construction comprising a lower
portion 13 and upper portion 14. The lower portion is fixed to the lower
surface of the motor assembly mounting platform 15 provided in the
housing. 16 represents reinforcing ribs of the lower portion. The upper
portion 14 of the sleeve is provided with a base portion 17 fixed to the motor
assembly fixing bosses 18 at the upper surface of the motor assembly
mounting platform by engaging the openings 18a provided on the base
portion over the bosses 18 (Figs 1 and 1A). The upper portion of the sleeve comprises an air flow interrupter 19 comprising a disc 20 provided across the upper end of the silencer cum guide sleeve above the mounting bracket 21 of the motor assembly. The disc 20 is provided with spaced openings 22 at the periphery thereof associated with arch like air flow obstructing baffles 23 (Fig 1A). 14a is the hole in disc 20 for the motor shaft. 24 is the seating collar of the mixer grinder for a jug or container (not shown) containing the content(s) to be ground and/or mixed (Fig 1).
During operation of the mixer grinder the axial fan rotates with the motor shaft and sucks in the atmospheric air through the air inlets 3 into the lower portion of the silencer sleeve and throws the air upwards. Atmospheric air travels up over the motor assembly and escapes into the surroundings
through the air outlets 4 via the space marked 25 between the
seating collar of the mixer grinder and the upper portion of the sleeve
and the space marked 26 between the upper portion of the sleeve and
the housing (Fig 1) thereby taking away the heat of the motor assembly
and cooling the motor assembly. The air flow is marked by arrows.
Noise generated within the mixer grinder during its operation especially
at high speed and resultant turbulence in the air flow and due to
aerodynamics i.e. noise generated by the fan blades cutting the air and also
due to mechanical and magnetic imbalances of the motor assembly is
dampened by the silencer sleeve. The noise level is further dampened
because of the controlled outflow of air through the openings 22 restrained
by the baffles 23 of the air interrupter. Because of the above reasons level of
noise being transmitted to the surroundings during operation of the mixer
grinder is considerably reduced and the mixer grinder operates at reduced
The mixer grinder may be circular or any other geometry / profile. The silencer cum guide sleeve and the air flow interrupter at the upper end of the sleeve may be of any other construction/geometry.
|Indian Patent Application Number||1067/MUM/2003|
|PG Journal Number||30/2007|
|Date of Filing||15-Oct-2003|
|Name of Patentee||KONINKLIJKE PHILIPS ELECTRONICS NV|
|Applicant Address||1,Groenewiudseweg,5621 BA Eindhoven,|
|PCT International Classification Number||B01F 015/06|
|PCT International Application Number||N/A|
|PCT International Filing date|