Electric heating – Microwave heating – Enclosed cavity structure
Reexamination Certificate
2000-01-14
2001-04-17
Leung, Philip H. (Department: 3742)
Electric heating
Microwave heating
Enclosed cavity structure
C219S400000, C126S02100R, C126S29900R
Reexamination Certificate
active
06218654
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a domestic appliance comprising an oven and a ventilator device in a common casing according to the preamble of the appended claim
1
and a flow control means and the use thereof in such an appliance.
PRIOR ART
Domestic appliances which in a common unit comprise a microwave oven and a ventilator hood are previously known. Such combinations of a ventilator hood and a microwave oven are intended to be installed over a range and offer efficient utilisation of the space above a range.
Usually, the ventilating duct in such domestic appliances has an outlet which at the time of installation is adjustable to suit various designs and placements of subsequent kitchen flues in a building. Often, as an alternative, the outlet of the ventilating duct can guide the flow in the duct to recirculation, e.g. when the building lacks a suitable kitchen flue, so that the ventilator hood can function as a recirculation ventilator, together with a suitable filter.
These known domestic appliances have a ventilator unit arranged directly opposite an outlet opening. Usually, the outlet opening is formed as a rectangular opening in the transition area between the top and back of the appliance. In this connection, the ventilator unit is formed as a radial ventilator with twin rotors, which are arranged on each side of a centrally located electric motor. The ventilator has a horizontal rotation axis extending in the transverse direction of the appliance. The diameter of the rotors essentially corresponds to the dimension of the outlet opening in the direction upwards-downwards or forwards-backwards. The ventilator unit forms a rectangular parallelepiped and can be placed in different turning positions around its rotation axis for adjustability between outlet upwards or backwards to a ventilating duct in the building or for outlet forward through a second outlet opening on the front of the appliance for recirculation.
One problem associated with this known construction is that the ventilator and the air currents give rise to high sound levels.
Furthermore, there are special problems associated with ventilator devices which are combined with an oven, such as combining a number of appliance components and ventilating ducts in a limited volume in a common casing. Therefore, there are problems of low ventilator efficiency because of uncontrolled flow in the appliance. In known appliances, a high percentage of the air which is blown out through the ventilator leaks into the outer casing of the appliance from a different location than the intended inlet opening.
SUMMARY OF THE INVENTION
The object of the present invention is to achieve an improved ventilator device in a domestic appliance comprising an oven and a ventilator device in a common casing.
In this connection, special objects are to lower the sound level of the ventilator device and to achieve improved controllability of air currents in the appliance.
These and other objects, which can be seen from the description below, have now been achieved by the invention by means of a domestic appliance and a flow control means, which are of the kind described in the introduction and which in addition have the features stated in the characterising clauses of claims
1
and
9
, and by a use of the flow control means according to claim
16
.
Thus, in the domestic appliance according to the invention, the ventilator is stationarily mounted on the inside of the casing, spaced from an outlet opening.
In addition, the ventilating duct has a flow control means arranged downstream of the ventilator on the inside of the casing for adjusting the ventilating duct to lead to any one of at least two different outlet locations.
In this way, it becomes possible to choose the location and the design of the ventilator inside the casing or cover of the appliance. For example, the ventilator can be given a larger radius or be located closer to the intake opening of the appliance. Greater possibilities are afforded for the design of a suitable ventilating duct in coaction between the ventilator and the other components of the appliance. In addition, it becomes possible to utilise a larger part of the area of the outlet opening for the outlet air, which means that an equally large volume flow rate can be ventilated at lower outlet velocities. This, in turn, leads to lower sound levels than have been possible in known appliances, in which ventilator constructions only allow a smaller part of the outlet opening to be utilised.
In a preferred embodiment the flow control means is adapted to change the direction of a flow in the ventilating duct. As a result, the adjustability of the flow control means and the optional location of the ventilator can be achieved in a simple way by the fact that the flow control means can be placed in various turning positions around an intake from the ventilator.
In a particularly preferred embodiment, the flow control means has a control means housing with a smaller inlet and a larger outlet in order to function as a diffuser. In this way, the velocity of flow in the outlet can be lowered, which leads to lower sound levels. At the same time, the ventilating duct can be given a limited cross-sectional area between the ventilator and the flow control means.
It is a preferred feature that the ventilator be given a relatively large radius, larger than the smallest dimension of the outlet opening, something which has been the case in the known solutions. By virtue of a larger radius, the peripheral speed of the ventilator can be reduced in relation to the flow rate, which leads to lower rotation speeds and thus lower sound levels. It is a particularly preferred feature that the ventilator be arranged in the form of a radial ventilator which rotates around an asymmetrically located, vertical rotation axis in an upper area of the appliance. In this way, the radius of the ventilator will only be limited by the horizontal cross-sectional dimensions of the appliance.
A flow control means according to the invention has an elongated control means housing and comprises an outlet opening, which is arranged along a long side, and an inlet opening, which is arranged along another side. The inlet opening has a smaller opening area than the outlet opening. In addition, a deflecting device is arranged to deflect and distribute the flow essentially uniformly at the outlet.
Such a flow control means has proved to be extremely suitable for controlling a flow to an outlet opening in a domestic appliance with a ventilator in combination with an oven. The flow control means according to the invention also affords great advantages in appliances which have a fixed outlet location.
In a preferred embodiment, the deflecting device comprises a plurality of deflecting means, which are essentially uniformly arranged along a projection of the inlet opening perpendicular to its essential geometrical plane and at the same time essentially uniformly arranged along a projection of the outlet opening perpendicular to its essential geometrical plane. In this way, deflection of the air current as well as a reduction of velocity and a uniform distribution of the same over the larger area of the outlet are achieved with a small loss of energy.
The deflecting means of the flow control means preferably comprises deflecting blades which are somewhat curved and have a leading edge facing the inlet opening and a trailing edge facing the outlet opening. In order to achieve good flow characteristics and little energy loss, it is particularly preferred that the leading edge of the blades be rounded and that the trailing edge be pointed.
REFERENCES:
patent: 4418261 (1983-11-01), Jailor et al.
patent: 4618756 (1986-10-01), Schwaderer et al.
patent: 5500508 (1996-03-01), Gerl
patent: 41 43 124 (1992-07-01), None
patent: 2 028 491 (1980-03-01), None
patent: 2 176 378 (1986-12-01), None
Krefman Stephen D.
Leung Philip H.
Rice Robert O.
Van Winkle Joel M.
Whirlpool Corporation
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