MX2008010418A - Domestic clothes drier with twin fan - Google Patents

Abstract

Dryer with a drum (1) where the clothes must be placed, one fan (5) blowing a drying air current through such drum, a condenser ( 3) in which such drying air current enters, a cooling air duct (4) blowing a second fresh air current through the condenser, produced by a second fan (6) connected to the air duct;at least one of these fans is composed of one set of external blades (10, 11, 12) and a second set of internal blades (21, 22, 23) that spin on a common axle (X), and the blades of the first set are laid out along one cylindrical structure, while the second set of blades are laid out along a second cylindrical structure inside the first one.

Description

DOMESTIC CLOTHING DRYER WITH DOUBLE HÉL Description The present invention relates to an improved type of clothes drying machine, preferably of the domestic type, which operates in a particularly effective manner. In the continuation of the present description, reference will be made to a simple clothing machine, but it is understood that the above explanation may also be applied in a manner identical to -and consequently also valid for- a combined washing and drying machine. Clothes drying machines are known which operate using different methods, in particular those which operate by means of condensation of a flow of hot air which is blown towards the rotor and which removes the moisture contained in the clothes or by externally dischag said clothes. humid hot air flow. Said clothes drying machines are generally described in European Patent Application No. EP 04 009650.5, in the name of the same applicant, to which, for the sake of brevity, I should reference. However, in order to help the reader, a short descriptive part of that document is included here. As is well known, these machines are manufactured by installing a ventilation and heating system, usually a fan consisting of a propeller and associated electric motor, which extracts the air from the outside and by means of suitable ducts heats and blows it towards the rotor that contains the clothes to be dried. A heating element is installed inside said duct and, properly activated, heats the air passing over it and is blown by said fan, in such a way that the hot air is introduced towards the rotor in order to originate the evaporation of moisture contained in clothing. After it is introduced into the rotor, the hot air causes the evaporation of the moisture contained in the clothes and consequently is practically saturated or completely saturated with it; said air is thus propelled by said fan, creating a continuous flow which is directed towards a condensing device suitable, usually consisting of a thermal exchanger through which it passes, along the so-called "hot" path, by said flow of humid hot air and, along the so-called "cold" path, by a flow of air substantially continuous continuous extracted from the environment and introduced back into the environment after passing through said exchanger. Conventionally, said air flow along the "cold" path is also activated and maintained by a ventilator operated by a respective electric motor. Such clothes drying machines are almost simple, inexpensive and operationally reliable machines, but, as is well known, they have the common deficiency that they are significantly noisy due to the air flow that is blown at a considerable speed into the ducts. suction and discharge. Consequently, the use of these machines is normally limited to certain periods, this making their use less attractive to the average user. The most immediate technical solution to achieve the circulation of said two air flows Separated is that of using the respective fans inserted inside the corresponding ducts and operated by respective motors that are controlled independently. Obviously said two fans use a non-significant amount of energy, due to, not only the mechanical friction factors which, however, are of limited importance, but also and in particular the energy that must be used in order to impart to the flows of respective air the desired speed, or pressure, at the necessary flow rate. Accordingly, it would be desirable, and this is the main object of the present invention, to provide a clothes dryer machine of external discharge or condensation type, which is provided with helices to dry and if it is necessary to cool the condenser and is capable of to offer a normal drying performance, but which is significantly more efficient, without increasing the complexity of the machine, while maintaining production at low cost. These and other objects that will be described below are achieved by providing a machine clothes dryer according to the claims that follow; the invention will be understood more clearly from the following description, provided in a unique manner by way of a non-limiting example with reference to the accompanying figures 1 to 7, in which: Fig. 1 shows a general schematic diagram of a drying machine of clothing provided with a condenser and two propellers that are connected together in a rigid manner, according to the prior art; Figs. 2 and 3 show two perspective views, that is, a front view and a side view, respectively, of a propeller for circulating the air in a machine according to the invention; Fig. 4 shows a front view of said propeller; Fig. 5 shows a cross-sectional view through the center of said propeller; Fig. 6 shows a front view of a variant of the embodiment of the propeller according to the invention; Fig. 7 shows, in the same diagram, two separate graphs that illustrate the advancement of the pressure and the consumption of electrical energy of the motor in a clothes dryer machine with a propeller according to the prior art (graph A) and with a propeller which is the same, but equipped with the present invention (graphic B), respectively. Characteristic curve for the new propeller, comparison between two helices under similar conditions. With reference to Fig. 1, in a clothes drying machine according to a preferred embodiment of the invention, a rotor 1 is provided for holding the clothes to be dried and has, associated therewith, a duct 2 for air circulation drying; the latter also passes through a condenser 3 which is able to condense the moisture present in the air passing through it, said condenser passing through a "cold" air flow, mainly one that is extracted from the environment and is transported to the said condenser 3 by means of an associated duct 4. Both the ducts 2 and 4 contain within them two respective helices 5, 6 to drive the respective cooling and drying air flows.

One of said helices, or both, consist of two groups of vanes which are placed on the outer surface of a respective cylindrical shape, said two cylindrical forms being understood in the non-material sense. Said cylindrical shapes are also coaxial and the radius of a first cylindrical shape is smaller than the radius of the second cylindrical shape. Essentially the two cylindrical shapes, and therefore also the two groups of blades, are inserted one inside the other, however without touching, as clearly illustrated in Figures 2 to 5. Blades 10, 11, 12 .. of the first group, or external group, are rigidly supported by a wall "P" positioned along a geometric base of the respective cylindrical shape, and the supporting structure of said helix is formed in this way. Advantageously, the vanes of the group of the internal vanes 20, 21, 22 ... of the second group are similarly supported on said wall "P" in such a way that the vanes of both groups are joined together and can rotate in synchrony.

Still with reference to Figures 2, 3 and 4, in order to avoid the damage of the vortices on the internal blades, advantageously the latter have a shape that is not flat but curved, that is, with the associated concavities Cl, C2, C3, etc., directed in the direction of rotation. In addition and preferably the free ends of the vanes of each group are connected by a respective reinforcing ring 7, 8. The propeller according to the invention is formed in this way. The mode of operation of this propeller will now be clear: in fact the air that is sucked into the cavity between the two groups of blades is formed outwardly by the external blades according to the known mechanical principles, while the air sucked into Inside the inner vanes, it is naturally blown outwards, that is to say, into said cavity, with a certain given speed that is added to the speed imparted by the external vanes through which it passes immediately afterwards, basically the operation similar to that of a double-stage propeller is presented, in which at least part of the sucked air is submits to the series action of the blades of the two groups. Obviously the flow of said air blown from the internal vanes also helps the movement of air sucked directly from the outside towards said cavity, this favoring the overall efficiency of the propeller. It can also be considered that the blown air outside the group of the internal blades is slightly decreased by the air sucked directly from the outside towards said cavity; however, the overall effect is an improvement in the efficiency of the propeller, as shown by Fig. 7, which shows two graphs illustrating the flow velocity of a propeller with and without the invention, graph A showing the pressure and the consumption of a propeller without the invention and the graph B showing the corresponding parameters of the same propeller to which the group of internal blades according to the invention has been added. With reference to Fig. 4, it has also been observed that in certain embodiments and in certain operating conditions, for example when the propeller must always operate in the same direction of rotation, or, as it occurs more frequently in a clothes drying machine, in a main direction of rotation, the efficiency of the propeller is further increased if the internal vanes are provided with an orientation that is not radial, but are inclined to a given angle "i" with respect to the radial plane passing through the latter, and in particular if said internal blades are inclined in such a way that, taking as a reference the direction of rotation "S" of the helix, the outer edges 45, 46, 47 of each internal blade are furthermore located later than the respective internal edges 45A, 46A, 47A, obviously in relation to the planes pl, p2, p3 passing through said respective blades. However, it is more generally possible to contemplate propellers that are operated in an alternate manner and for identical periods in each direction of rotation; in this case it is obviously advantageous if the blades of the propeller also do not have preferential shapes, but on the contrary, as shown by way of example in Fig. 6, all the internal blades are flat and are placed radially.

Claims (7)

1. - - CLAIMS 1. Clothes drying machine or combined laundry and laundry machine comprising a rotor containing the clothes to be dried, at least a first helix capable of blowing a first flow of drying air through said rotor, optionally a condenser within which said flow of drying air is passed through and an associated cooling air duct which transports a second flow of fresh air through said condenser, said second flow being operated by a second propeller associated with said air duct , characterized in that at least one of said helices is formed by means of a first group of external blades and a second group of internal blades rotating with respect to a common axis, because the blades of the first group of blades are distributed on a first form cylindrical, and because the vanes of the second group of vanes are placed along a second cylindrical shape which is different from the first cylindrical shape and is ocan within said first cylindrical shape.
2. 2. Machine according to the claim 1, characterized in that a base of the cylinder that is defined by the first group of vanes is at least partially closed by a wall.
3. Machine according to claim 2, characterized in that the vanes of the second group of vanes arranged internally are fixed at one of their ends to said wall.
4. Machine according to any of the preceding claims, characterized in that said blades of said first group are radial with respect to said common axis.
5. Machine according to claim 4, characterized in that said vanes of the second group of internal vanes are oriented in a non-radial direction with respect to said common axis and have a given inclination with respect to the respective radial planes passing through they.
6. Machine according to claim 5, characterized in that said given inclination is such that the outer edges of the respective internal blades are located later than the respective internal edges.
7. 7. Machine according to any of the preceding claims, characterized in that said internal blades have a concave surface directed in the direction of rotation of said propeller. /