Fan unit for a ventilator

Abstract

Fan unit for a ventilator, comprising a housing with a suction connector which forms an inlet duct for the suction-side inflow of a fluid into the housing, a pressure connector which forms an outlet duct for the pressure-side outflow of the fluid from the housing, and a fan impeller mounted rotatably in the housing and being configured, by rotation, to suck in the fluid via the suction connector and to convey it through the inlet duct into the housing, and to eject the fluid again via the pressure connector and to convey it through the outlet duct out of the housing. The suction connector has at least one flow guiding element on its inner face which faces the inlet duct and defines an inlet duct nominal diameter, by which element an inlet duct internal diameter differing at least in sections from the inlet duct nominal diameter is set.

Claims

1. A fan unit for a ventilator, wherein the fan unit comprises a housing with a suction connector which forms an inlet duct for a suction-side inflow of a fluid into the housing, and a pressure connector which forms an outlet duct for a pressure-side outflow of the fluid from the housing, as well as a fan impeller which is mounted rotatably in the housing and is configured and arranged, by way of rotation, to suck in the fluid via the suction connector and to convey it through the inlet duct into the housing, and to eject the fluid again via the pressure connector and to convey it through the outlet duct out of the housing, the suction connector comprising at least one flow guiding element on its inner face which faces the inlet duct and defines an inlet duct nominal diameter (D.sub.N), the at least one flow guiding element setting an inlet duct internal diameter (D.sub.I) which differs at least in sections from the inlet duct nominal diameter (D.sub.N).

2. The fan unit of claim 1, wherein a diameter ratio of the inlet duct internal diameter D.sub.I to the inlet duct nominal diameter D.sub.N is from 1.05 to 1.6.

3. The fan unit of claim 1, wherein the at least one flow guiding element is a groove which is made in the inner face and increases the inlet duct internal diameter (D.sub.I) in comparison with the inlet duct nominal diameter (D.sub.N).

4. The fan unit of claim 1, wherein the at least one flow guiding element is a rib which projects from the inner face and reduces the inlet duct internal diameter (D.sub.I) in comparison with the inlet duct nominal diameter (D.sub.N).

5. The fan unit of claim 1, wherein a plurality of flow guiding elements including the at least one flow guiding element are arranged distributed equidistantly over a circumference of the inner face.

6. The fan unit of claim 1, wherein the at least one flow guiding element has an end side, said end side being rounded on a side which faces the inflowing fluid.

7. The fan unit of claim 1, wherein the at least one flow guiding element comprises two end sides, one end side that is on a side which faces the inflowing fluid being rounded or angular, and the other end side that is on a side which faces away from the inflowing fluid being rounded or angular.

8. The fan unit of claim 1, wherein the at least one flow guiding element has a symmetrical wing profile and/or is configured as a curved wing and/or is configured with notches over an axial length.

9. The fan unit of claim 1, wherein the at least one flow guiding element is configured with apertures/holes therein, with the result that an exchange flow from one flow duct to the next is produced and/or wherein the at least one flow guiding element tapers in the flow direction of the fluid (or vice versa).

10. The fan unit of claim 1, wherein the at least one flow guiding element has a width B, that is to say its extent in the tangential direction of the suction connector or its inner face.

11. The fan unit of claim 1, wherein the at least one flow guiding element has a width B with a course of the width B and/or has a width B ranging from 0.4 mm to 2.2 mm.

12. The fan unit of claim 11, wherein ribs extend in a radial direction as far as a center axis of the suction connector and are in contact with one another there.

13. The fan unit of claim 1, wherein the at least one flow guiding element extends in its longitudinal extent direction parallel to a center axis of the suction connector.

14. The fan unit of claim 1, wherein the at least one flow guiding element extends in its longitudinal extent direction at an angle in an inclined manner with respect to a center axis of the suction connector.

15. The fan unit of claim 14, wherein the angle is greater than 0 and less than or equal to 45.

16. The fan unit of claim 1, wherein the ratio between the inlet duct internal diameter (D.sub.I) and the inlet duct nominal diameter (D.sub.N) is from 0.6 to 1.4.

17. The fan unit of claim 1, wherein the fan unit is a radial fan unit.

18. The fan unit of claim 1, wherein a fan impeller comprises a plurality of blade elements, the blade elements being equipped at least partially with in each case one winglet which runs at least in sections on at least one axial longitudinal side of the blade element.

19. The fan unit of claim 18, wherein the winglet has an extent of from 1 to 20 of a circumference of the fan impeller and/or wherein the extent of the winglet increases from a radial inside of the fan impeller to a radial outside of the fan impeller.

20. The fan unit of claim 1, wherein a fan impeller is equipped with at least one disk on only one axial side, and the disk is arranged only on that axial side which lies opposite an axial side, equipped with the winglets, of the fan impeller.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features and advantages of the invention result from the following description of exemplary embodiments of the invention which are not to be understood to be restrictive, which invention will be described in greater detail in the following text with reference to the drawing, in which, diagrammatically:

(2) FIG. 1 shows an exploded view of one exemplary embodiment of the fan unit according to the invention,

(3) FIG. 2 shows a perspective partial view of the fan unit from FIG. 1,

(4) FIG. 3 shows a perspective partial view of a further embodiment of a fan unit according to the invention,

(5) FIGS. 4(a)-(c) show a perspective detailed view of a suction connector of the fan unit from FIG. 2, a perspective detailed view of a suction connector of a further exemplary embodiment of a fan unit according to the invention, and a perspective detailed view of a suction connector of a further exemplary embodiment of a fan unit according to the invention,

(6) FIG. 5 shows a cross-sectional view through the suction connector of the fan unit from FIG. 2,

(7) FIG. 6 shows a pressure diagram which illustrates a comparison of the fan unit from FIG. 2 with a fan unit in accordance with the prior art,

(8) FIG. 7 shows a perspective view of one exemplary embodiment of a fan unit, and

(9) FIG. 8 shows a perspective view of a fan impeller.

(10) In the different figures, parts which are equivalent with regard to their function are always provided with the same designations, with the result that they are also as a rule described only once.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

(11) FIG. 1 is an exploded view in a perspective illustration of one exemplary embodiment of the fan unit 1 according to the invention. The fan unit 1 can particularly preferably be used in a ventilator (not shown in further detail) for the ventilation of persons. As can be seen in FIG. 1, the illustrated fan unit 1 comprises a housing 2 with a suction connector 3 which forms an inlet duct 4 for the suction-side inflow of a fluid, in particular a breathing gas, into the housing 2. Furthermore, the fan unit 1 or the housing 2 comprises a pressure connector 5 which forms an outlet duct 6 for the pressure-side outflow of the fluid from the housing 2. Furthermore, it can be gathered from FIG. 1 that the fan unit 1 comprises a fan impeller 7 which is mounted rotatably in the housing 2 and, by way of rotation, sucks the fluid in via the suction connector 3 and conveys it through the inlet duct 4 into the housing 2 and subsequently ejects the fluid again via the pressure connector 5 and conveys it through the outlet duct 6 out of the housing. To this end, the fan impeller 7 is received substantially completely in the housing 2. In the case of the exemplary embodiment of the fan unit 1 shown in FIG. 1, the rotation is brought about via a drive motor 8, in particular an electric motor 8, which is not absolutely necessary, however. In addition, the electric motor 8 can likewise be received substantially completely in the housing 2 or can be arranged merely partially or else completely outside the housing 2 and can be connected in a driving manner to the fan impeller 7. As can be gathered from FIG. 1, moreover, the fan unit 1 is a radial fan unit, that is to say the fan impeller 7 is arranged in the housing 2 in such a way that the fluid is sucked in via the suction connector 3 in the axial direction of the fan impeller 7 and is ejected in the radial direction. In the case of the fan unit 1 which is shown in FIG. 1, the axial direction of the fan impeller 7 coincides with the center axis 9 of the fan unit 1 or the suction connector 3, without being restricted thereto, however.

(12) Furthermore, it can be gathered from FIG. 1 that the suction connector 3 has at least one flow guiding element 10, in the present case a plurality of flow guiding elements 10 on its inner face which faces the inlet duct 4 and sets or determines an inlet duct nominal diameter D.sub.N (see FIG. 5). In the case of the fan unit 1 which is shown in FIG. 1, the flow guiding elements 10 are configured as grooves. The flow guiding elements 10 or grooves 10 set an inlet duct internal diameter D.sub.I which differs from the inlet duct nominal diameter D.sub.N, that is to say is greater in the present case than the inlet duct nominal diameter D.sub.N. The plurality of grooves 10 are arranged distributed equidistantly over the circumference of the inner face of the suction connector 3, as can be seen clearly in FIG. 1.

(13) FIG. 2 shows a perspective partial view of the fan unit 1 with the housing 2 from FIG. 1.

(14) For comparison purposes with the fan unit 1 from FIG. 2, FIG. 3 shows a perspective partial view of a further exemplary embodiment of the fan unit 20 according to the invention. In contrast to the fan unit 1 from FIG. 2, in the case of a suction connector 21 of the fan unit 20, a plurality of flow guiding elements 22 are configured as ribs 22 which project from the inner face of the suction connector 21. In the case of the exemplary embodiment of the fan unit 20 shown in FIG. 3, a total of four ribs 22 of this type are shown, without being restricted to said number. The flow guiding elements 22 or ribs 22 set an inlet duct internal diameter D.sub.I which differs from the inlet duct nominal diameter D.sub.N, that is to say which is smaller in the case of the present fan unit 20 than the inlet duct nominal diameter D.sub.N. The (in the present case, four) ribs 22 are arranged distributed equidistantly over the circumference of the inner face of the suction connector 21, as can be seen clearly in FIG. 3. Since the ribs 22 of the fan unit 20 do not extend in the radial direction as far as the center axis 9 of the suction connector 21 and accordingly are not in contact with one another there, the inlet duct internal diameter D.sub.I which is set by way of the ribs 22 of the fan unit 20 is greater than zero.

(15) FIG. 4 shows a perspective detailed view (a) of the suction connector 3 of the fan unit 1 from FIG. 2 and, furthermore, shows a perspective detailed view (b) of a suction connector 23 of a further exemplary embodiment of a fan unit according to the invention (not shown here in further detail) and a perspective detailed view (c) of a suction connector 24 of a further exemplary embodiment of a fan unit (likewise not shown in greater detail) according to the invention. The fan units which are not shown in the present case and in each case comprise the suction connectors 23 and 24 can be of identical construction to the fan unit 1 from FIG. 1 apart from the respective suction connectors 23 and 24.

(16) In the case of the suction connector 3 of the fan unit 1, it can be seen clearly in FIG. 4(a) that the flow guiding elements 10 which are configured as grooves extend in their respective longitudinal extent directions parallel to the center axis 9 of the suction connector 3, that is to say accordingly run in an axially parallel manner. This refinement has proven to be particularly efficient with regard to as great a pressure increase as possible for the fluid which flows in the inlet duct 4. The flow guiding elements can have a straight course in their respective longitudinal extent directions.

(17) Although the suction connector 23 from FIG. 4(b) likewise comprises flow guiding elements 25 which are configured as grooves, they do not run in their longitudinal extent directions in an axially parallel manner with respect to the center axis 9, but rather are inclined at an angle with respect to the center axis 9 of the suction connector 23. The angle of inclination of the grooves 25 with respect to the course of the center axis 9 is preferably more than 0 (0 corresponds to the axially parallel orientation) and less than or equal to 45. The flow guiding elements can have a curved or bent course in their respective longitudinal extent directions. The flowing fluid can experience a boost or swirl as a result of the curved or bent course of the flow guiding elements.

(18) In the case of the suction connector 24 in FIG. 4(c), the flow guiding elements 26 which are once again configured as grooves are likewise oriented inclined at an angle with respect to the center axis 9, but are inclined precisely in the opposite direction in comparison with the grooves 25 of the suction connector from FIG. 4(b). In this refinement, a preferred angle of inclination can accordingly be defined as an angle between less than 0 and greater than or equal to 45.

(19) FIG. 5 shows a cross-sectional view through the suction connector 3 of the fan unit 1 from FIG. 2. The inlet duct nominal diameter D.sub.N which is defined by way of the inner face of the suction connector 3 can be seen clearly in FIG. 5. The flow guiding elements 10 which are introduced into the inner face in the form of grooves set an inlet duct internal diameter D.sub.I which, in the case of the suction connector 10 of the fan unit 1 from FIG. 2, is greater than the inlet duct nominal diameter D.sub.N and is delimited by way of the groove bottom of the respective groove 10. Furthermore, in the cross-sectional view of FIG. 5, a width B of one of the flow guiding elements 10, that is to say its extent in the tangential direction of the suction connector 3 which is of hollow-cylindrical configuration in the present case or of its inner face, is specified. In the case of the exemplary embodiment which is shown, the width B of the flow guiding element 10 is a groove width B of the grooves 10. It is to be understood that the width of the flow guiding element 22 can also be understood as a web width or a rib width in the case of the fan unit 20 which is shown in FIG. 3. Accordingly, the flow element width is generally the extent direction of the respective flow guiding elements 10, 22, 25, 26 in the tangential direction of the respective suction connectors 3, 21, 23 and 24.

(20) It has emerged, that in the case of a configuration of the flow guiding elements as grooves as in the case of the grooves 10 of the fan unit 1 which are oriented in an axially parallel manner, a maximum pressure gain or pressure rise in the inlet duct 4 can be achieved at a constant rotational speed of the fan impeller 7 in comparison with conventional suction connectors without flow guiding elements if a total of 13 axially parallel grooves 10 which are arranged distributed equidistantly along the inner circumference of the inner face of the suction connector 3 are provided in each case with a width B of from 0.3 to 2.1 mm, preferably from 0.5 to 1.5 mm, for example also from 0.8 to 1.2 mm. According to the invention, the width B is also always adapted in proportion to the number of grooves or ribs. According to the invention, the relation of the overall width B of the ribs (for example, eight 1 mm ribs) to the free diameter of the inflow duct is 8 mm to 16 mm, and the ratio of the inflow duct area to the area blocked by way of the ribs is preferably in the range from 1.1 to 1.6, for example also from 1.2 to 1.4 or approximately 1.2.

(21) The diameter ratio of the inlet duct internal diameter D.sub.I to the inlet duct nominal diameter D.sub.N is from 1.05 to 1.6, preferably from 1.1 to 1.4, particularly preferably from 1.2 to 1.3.

(22) In the case of flow guiding elements which are configured as ribs, such as, for example, in the case of the fan unit 20 which is shown in FIG. 3, a maximum pressure gain can be achieved in the inlet duct 4 by way of a total of eight ribs 22 which are arranged distributed equidistantly in the circumferential direction along the inner face of the suction connector 21.

(23) In general, the ribs 22 might have any conceivable shape.

(24) The end side 22a of the ribs is rounded, for example, on the side which faces the inflowing fluid.

(25) The ribs can be angular and/or rounded at the inlet and outlet of the fluid.

(26) The ribs can taper from the inlet toward the outlet of the fluid (or vice versa) and can therefore have a profile of the width B.

(27) The ribs can have a symmetrical wing profile.

(28) The ribs can be configured as a curved wing.

(29) The ribs can be configured with notches over the axial running length.

(30) The ribs can be configured with apertures/holes in the ribs, with the result that an exchange flow from one rib flow duct to the next is produced.

(31) FIG. 6 illustrates a pressure diagram which shows a comparison of the fan unit 1 from FIG. 2 with a fan unit according to the prior art, the fan unit 1 comprising (as described above and as shown in FIG. 5) 13 axially parallel grooves 10 which are arranged distributed uniformly on the inner face of the suction connector 3 as flow guiding elements.

(32) The pressure p/p.sub.opt which is standardized to an optimum operating point of the fan unit (not shown herein) according to the prior art, that is to say a fan unit with a suction connector without flow guiding elements in the sense of the invention, is plotted along the ordinate of the pressure diagram, and the volumetric flow Q/Q.sub.opt which is standardized to an optimum operating point of the fan unit according to the prior art is plotted along the abscissa. A pressure curve of the conventional fan unit according to the prior art is drawn as a dashed curve 27 in the pressure diagram, and a pressure curve of the fan unit 1 in accordance with an exemplary embodiment of the invention disclosed herein is drawn as a solid curve 28.

(33) It can be seen clearly in FIG. 6 that, at Q/Q.sub.opt=1.0, the optimum pressure p/p.sub.opt (likewise equal to 1.0) of the conventional fan unit (curve 27) is reached. In contrast, the curve 28 of the fan unit 1 in accordance with the exemplary embodiment of the invention described herein, reaches a considerably higher pressure at the same volumetric flow (=same rotational speed of the fan impeller 7), accordingly p/p.sub.opt>1.0, in the present case approximately p/p.sub.opt=1.1. In this way, a pressure increase of the fluid at the same rotational speed of the fan impeller 7 can be achieved solely by way of the provision of the flow guiding elements 10 in the inlet duct 4.

(34) The fan unit according to the invention disclosed herein is not restricted to the embodiments disclosed herein, but rather also comprises identically acting further embodiments which result from technically appropriate further combinations of the features of the fan unit which are described herein. In particular, the features and combinations of features which are mentioned in the general description and the description of the figures and/or are shown alone in the figures can be used not only in the respective combinations specified explicitly herein, but rather also in other combinations or on their own, without departing from the scope of the present invention.

(35) In one preferred embodiment, the fan unit according to the invention is used for operating ventilators for the ventilation of persons, for example persons with insufficient or suspended spontaneous respiration, by a fluid, in particular a breathing gas, being conveyed by means of the fan unit, that is to say being sucked in on the suction side and being discharged again on the pressure side at a predefined pressure, and subsequently being fed to the person using the ventilator.

(36) FIG. 7 shows, in the case of flow guiding elements which are configured as ribs, such as for example in accordance with the fan unit 20 which is shown in FIG. 3, that a maximum pressure gain can be achieved in the inlet duct 4 by way of a total of 2-30 ribs 22 which are arranged distributed equidistantly in the circumferential direction along the inner face of the suction connector 21.

(37) In general, the ribs 22 might assume any conceivable shape.

(38) The end side 22a of the ribs is rounded, for example, on the side which faces the inflowing fluid.

(39) The ribs can be angular and/or rounded at the inlet and outlet of the fluid.

(40) The ribs can taper from the inlet toward the outlet of the fluid (or vice versa) and can therefore have a profile of the width B.

(41) The ribs can have a symmetrical wing profile.

(42) The ribs can be configured as a curved wing.

(43) The ribs can be configured with notches over the axial running length.

(44) The ribs can be configured with apertures/holes in the ribs, with the result that an exchange flow from one rib flow duct to the next is produced.

(45) The comments on FIG. 7 can likewise be applied to grooves.

(46) In general, the flow guiding elements might assume any conceivable shape.

(47) The end side 22a of the flow guiding elements is rounded, for example, on the side which faces the inflowing fluid.

(48) The flow guiding elements can be angular and/or rounded at the inlet and outlet of the fluid.

(49) The flow guiding elements can taper from the inlet toward the outlet of the fluid (or vice versa) and can therefore have a profile of the width B.

(50) The flow guiding elements can have a symmetrical wing profile.

(51) The flow guiding elements can be configured as a curved wing.

(52) The flow guiding elements can be configured with notches over the axial running length.

(53) The flow guiding elements can be configured with apertures/holes in the flow guiding elements, with the result that an exchange flow from one flow duct to the next is produced.

(54) FIG. 8 shows a fan impeller 7 in a perspective view. Here, the fan impeller 7 is equipped with a plurality of blade elements 29, a disk 32 which is configured as a carrying disk 33, and a hub 37 for connection to a drive shaft. Here, the blade elements 29 are fastened to the carrying disk 33 and preferably also to the hub 37, and, for example, are connected to them in one piece. The fan impeller 7 can also be configured without disks 32 and, in particular, without carrying disk 33, for example as a star fan impeller.

(55) The preferred rotational direction of the fan impeller 7 is illustrated here by way of an arrow. The blade elements 29 have a suction side 38 and a pressure side 39. The orientation shown here of the suction side 38 and the pressure side 39 results for the rotational direction shown here of the fan impeller 7.

(56) In order to effectively and reliably prevent the exchange flow from the side space and from the pressure side 39 to the suction side 38 in the direction of the side space or an axial side, the fan impeller 7 is equipped with winglets 31. Here, each blade element 29 is equipped with a winglet 31. The winglets 31 run in each case along an axial longitudinal side 30 of the blade element 29. In the refinement of the invention shown here, the winglets 31 point in the direction of the suction side 38 of the respective blade element 29. An advantageous pressure increase and also a considerable increase in the degree of efficiency could be observed for a fan impeller 7 of this type.

(57) The fan impeller 7 shown here is integrated, for example, into the fan unit 1 in such a way that intake is carried out axially and ejection is carried out radially. Here, the intake side lies on the axial side 36 with the winglets 31.

(58) In the refinement shown here, the fan impeller 7 is equipped with the disk 32 only on one axial side 34. Here, the disk 32 which is configured as a carrying disk 33 is arranged on that axial side 34 of the fan impeller 7 which lies opposite that axial side 36 of the fan impeller 7 which is equipped with the winglets 31.

(59) In one development, a disk 32 which is not shown here in greater detail and is configured as a cover disk 35 can also be provided. Here, the cover disk 35 can be arranged in addition to the carrying disk 33 on the axial side 36 or can replace the carrying disk 33.

LIST OF REFERENCE NUMERALS

(60) 1 Fan unit 2 Housing 3 Suction connector 4 Inlet duct 5 Pressure connector 6 Outlet duct 7 Fan impeller 8 Drive motor 9 Center axis 10 Flow guiding element/groove 20 Fan unit 21 Suction connector 22 Flow guiding element/rib 23 Suction connector 24 Suction connector 25 Flow guiding element/groove 26 Flow guiding element/groove 27 Pressure curve of a fan unit according to the prior art 28 Pressure curve of 1 29 Blade element 30 Longitudinal side 31 Winglet 32 Disk 33 Carrying disk 34 Side 35 Cover disk 36 Side 37 Hub 38 Suction side 39 Pressure side B Width of a flow guiding element D.sub.I Inlet duct internal diameter D.sub.N Inlet duct nominal diameter p Pressure p.sub.opt Pressure at an optimum operating point of a fan unit according to the prior art Q Volumetric flow Q.sub.opt Volumetric flow at an optimum operating point of a fan unit according to the prior art