Impeller for a ventilation unit and ventilation unit comprising said impeller

Abstract

An impeller for a ventilation unit, especially for use in plants for the aerobic treatment of organic waste, is provided. The impeller comprises a housing, a pair of mutually facing plates received within the housing and provided centrall with a through-hole for a cylindrical hub, and a plurality of first radial blades arranged between the plates. The impeller further comprises second radial blades arranged on at least one plate, on its side facing the inner wall of the housing and extending from the cylindrical hub toward the periphery for creating an under-pressure zone in the central region of the impeller itself, at its hub. Thanks to this measure, condensate water deriving from the humidity of the air sucked/blown by the ventilation unit is prevented from leaking along the rotation shaft of the impeller, towards its motor and towards the outside environment.

Claims

1. An impeller for a ventilation unit, comprising a housing, a pair of solid disk-like plates, received within said housing arranged mutually facing and parallel at a certain distance from each other and provided centrally with a through-hole for a cylindrical hub, a plurality of first radial blades arranged between said plates and extending from the cylindrical hub, wherein on at least a first one of said plates, on its side opposite to a side facing a second one of said plates and facing an inner wall of said housing there are provided a plurality of second radial blades extending from said cylindrical hub towards a periphery of said at least a first one of said plates, said second radial blades cooperating, in use, with said inner wall of said housing for creating, at the cylindrical hub of said plates, a zone having a pressure lower than that in a peripheral zone of said plates.

2. The impeller according to claim 1, wherein said second radial blades extend perpendicularly to a surface of said at least a first one of said plates, between said at least a first one of said plates and said inner wall of said housing.

3. The impeller according to claim 1, wherein said first radial blades and said second radial blades are arranged equally spaced along a circumference of said at least a first one of said plates of said impeller.

4. The impeller according to claim 3, wherein said second radial blades are provided in a number equal to that of said first radial blades and are provided in an offset arrangement with respect to the latter along the circumference of said at least a first one of said plates of said impeller.

5. The impeller according to claim 1, wherein said first radial blades and said second radial blades have a curved profile that gives them a concave shape.

6. A ventilation unit, comprising: an impeller comprising a housing and a pair of solid disk-like plates received within said housing and arranged mutually facing and parallel at a certain distance from each other and provided centrally with a through-hole for a cylindrical hub, a plurality of first radial blades arranged between said plates and extending from said cylindrical hub; a rotation shaft connected to said cylindrical hub; and a motor for driving in rotation said rotation shaft, wherein on at least a first one of said plates of said impeller, on its side opposite to a side facing a second one of said plates and facing an inner wall of said housing there are provided a plurality of second radial blades extending from said cylindrical hub towards a periphery of said at least a first one of said plates, said second radial blades cooperating, in use, with the inner wall of said housing for creating, at said cylindrical hub of said plates, a zone having a pressure lower than that in a peripheral zone of said plates, whereby, when said motor drives in rotation said rotation shaft, a pressure inside said housing in a central region of said impeller is lower than a pressure inside of said housing in a peripheral region of said impeller.

7. The ventilation unit according to claim 6, wherein said second radial blades extend perpendicularly to a surface of said at least a first one of said plates, between said at least a first one of said plates and said inner wall of said housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Features and advantages of the present invention will become more apparent from the detailed description of a preferred embodiment of the impeller for ventilation unit and of the ventilation unit according to the present invention, provided by way of non-limiting example, with reference to the attached drawings, in which:

(2) FIG. 1 is a perspective view of an impeller according to the invention;

(3) FIG. 2 is a side view of the impeller of FIG. 1;

(4) FIG. 3a is a perspective view of a ventilation unit incorporating the impeller of FIGS. 1 and 2;

(5) FIG. 3b shows, in a sectional view, a detail of the ventilation unit of FIG. 3a;

(6) FIGS. 4a e 4b show schematically an exemplary application of the ventilation unit of FIG. 3a to a plant for the aerobic treatment of organic waste.

DESCRIPTION OF A PREFERRED EMBODIMENT

(7) With reference to FIGS. 1 and 2, the impeller for ventilation unit 1 according to the invention comprises a housing (not shown in FIGS. 1 and 2, but visible in FIGS. 3a, 3b) which houses at its inside a pair of solid disk-like plates 3a,3b, arranged mutually parallel and facing each other at a certain distance from each other.

(8) Centrally the plates 3a,3b have a through-hole for a cylindrical hub 5 provided for receiving the rotation shaft of the impeller 1.

(9) From the hub 5, a plurality of first radial blades 7 extend between the plates 3a,3b and are provided for moving the air flow to be sucked or blown by the ventilation unit.

(10) Preferably said first radial blades are not straight, but have a curved profile allowing to increase their efficiency, said curved profile being selected so that they present a concave surface to the air flow.

(11) According to the invention, at least a first one of the plates 3a,3b of the impeller 1 has, on its side opposite to the side facing the second of said plates 3b,3a, a plurality of second radial blades 9a extending from the hub 5 towards the periphery of said at least first plate 3a,3b.

(12) Preferably, the second radial blades 9a too are not straight but have a curved profile similar to that of the first radial blades 7.

(13) It will be evident that said second radial blades 9a extend between the corresponding plate of the impeller and the inner wall of the housing of the impeller itself.

(14) Consequently, thanks to the presence of the second radial blades 9a, when the impeller 1 is driven in rotation around its rotation shaft, a zone of under-pressure is created in the central portion of the plates 3a,3b of the impeller 1, at hub 5; in other words, in use, the pressure in the central region of the impeller 1 is lower than the pressure in the peripheral region of said impeller 1. By means of said under-pressure zone, the condensate water deriving from the humidity of air cannot reach the hub and leak along the rotation axis of the impeller.

(15) The presence of said second radial blades 9a thus allows to attain the object set forth above.

(16) As can be seen in FIG. 1, both the first radial blades 7 and the second radial blades 9a are preferably arranged equally spaced along the circumference of the impeller 1.

(17) In addition, the second radial blades 9a are preferably provided in a number equal to that of the first radial blades 7 and are provided in an offset arrangement with respect to the latter along the circumference of the impeller 1.

(18) Depending on the requirements, the second radial blades can be provided only on one of the plates 3a,3b, or on both plates 3a,3b, on the side opposite to the side facing the other plate 3b,3a, respectively.

(19) In FIG. 3a there is shown a ventilation unit 10 incorporating an impeller 1 according to the invention.

(20) In particular, in the illustrated embodiment said ventilation unit 10 is a ventilation unit with flow reversal allowing to alternately suck/blow air into a piping arrangement 12 without changing the rotation direction of the impeller 1.

(21) The ventilation unit 10 includes a first duct or suction duct 16a and a second duct or delivery duct 16b connected to the housing 14 of the impeller 1.

(22) In particular, in the illustrated embodiment said first duct or suction duct 16a and said second duct or delivery duct 16b connect said housing 14 to a deflecting unit 18.

(23) Thanks to the presence of suitable deflecting elements 20 driven by an actuator 22, said deflecting unit 18 is capable of selectively connecting said suction duct 16a and said delivery duct 16b to the outer environment or to the piping arrangement 12, so as to suck air from said piping arrangement and blow air into it in an alternate manner.

(24) FIG. 3b shows very schematically in a cross-sectional view the detail of the ventilation unit 10 concerning the connection of the rotation axis of said ventilation unit to the housing 14 of the impeller 1 according to the invention.

(25) As can be well seen in this Figure, the presence of the second radial blades 9a on the side of the plate 3a opposite to the other plate 3b and facing the inner wall of the housing 14 allows to create an under-pressure zone in the central region of the impeller 1, at hub 5, thus avoiding the risk of leakages of condensate water along the rotation axis 24 of the impeller 1, towards the motor of the impeller and towards the outer environment.

(26) It will therefore be evident to the person skilled in the art that the impeller 1 according to the invention allows to efficiently attain the aimed object.

(27) It will also be evident that what has been described above with reference to the embodiment shown has been provided only by way of example and that several modifications and variants are possible without departing from the scope of the invention as defined by the appended claims.

(28) In particular, the second radial blades 9a can be replaced with other equivalent means for creating, in the central region of the impeller 1 according to the invention, a zone with a pressure lower than that of the peripheral region of the impeller 1.

(29) As mentioned in advance above, said impeller is especially advantageous for being used in ventilation units employed in plants for the aerobic treatment of organic waste and the like.

(30) In this respect FIGS. 4a e 4b show an example of possible application of the invention to the aerobic treatment of organic waste.

(31) In such application a plurality of ventilation units 10 are connected on one part, through their respective piping arrangements 12, to a bio-oxidation area where the organic waste to be subjected to aerobic treatment is located, and on the other part to the outer environment, through a discharge piping arrangement 300 and a bio-filter 200 for filtering air before it is exhausted to the outer environment.

(32) The ventilation units 10 with flow reversal allow to alternately suck an air flow from the outer environment and blow it into the bio-oxidation area 100as indicated by the arrows F1 in FIG. 4aor to suck an air flow from the bio-oxidation area 100 and exhaust it to the outer environment through the discharge piping arrangement 300 and the bio-filter 200as indicated by the arrows F2 in FIG. 4b.

(33) In both cases, the use of impellers according to the invention in ventilation units 10 advantageously allows to prevent condensate water from leaking along the rotation shafts of said impellers towards their respective motors and towards the outer environment.

(34) This measure is especially convenient in the operation mode shown in FIG. 4b, as the air sucked from the bio-oxidation area 100 is particularly humid and charged with contaminants.

(35) The impeller according to the present invention can be made of different materials depending on its intended applications. For applications to the treatment of organic waste, it is preferably made of metal materials such as steel, or other materials suitable for withstanding chemical aggression by components that may be present especially in the contaminated air flow coming from the bio-oxidation area.