Method for determining a fluid delivery parameter

Abstract

The invention relates to a method for determining a fluid conveying parameter, a fluid conveying device, particularly for determining a volumetric flow, comprising the steps of Determining excitation information for mechanical excitation of at least one fluid conveying element of the fluid conveying device in at least one spatial direction by at least one first sensor means, Providing operating information, comprising at least a value of an operating variable of the fluid conveying device by means of a providing means, Analyzing the information provided and determined, Determining a fluid conveying parameter, particularly a volumetric flow, of the fluid conveying device based on the analyzed information.

Claims

1. A method for determining a fluid conveying parameter of a fluid conveying device, comprising the steps of: determining excitation information for a mechanical excitation of at least one fluid conveying element of the fluid conveying device in at least one spatial direction by at least one first sensor; providing operating information including at least a value of an operating variable of the fluid conveying device; accessing a memory storing at least one characteristic field for one or more operating variables of the fluid conveying device; analyzing the excitation information and the operating information to determine a current working point of the fluid conveying device; determining the fluid conveying parameter of the fluid conveying device based on the analyzed information, wherein the fluid conveying parameter comprises a volumetric flow.

2. The method of claim 1, wherein the mechanical excitation comprises one or more oscillations of the fluid conveying element.

3. The method of claim 2, wherein the step of determining excitation information comprises determining at least one of an amplitude and a change in amplitude of the mechanical excitation.

4. The method of claim 1, wherein the step of determining excitation information comprises determining an amplitude or a change in amplitude of the mechanical excitation.

5. The method of claim 1, further comprising the step of evaluating the operating information before analyzing the excitation information using a stored and/or predetermined field for operating information.

6. The method of claim 1, wherein the fluid conveying device comprises a fan and the fluid conveying element comprises an impeller of the fan.

7. The method of claim 1, wherein the operating information comprises performance information of the fluid conveying device.

8. The method of claim 7, wherein the performance information comprises one or more of current, voltage, power consumption and rotational speed.

9. The method of claim 1, wherein the excitation information is determined as a function of time.

10. The method of claim 9, wherein the operating information is provided as a function of time.

11. The method of claim 10, further comprising the step of preparing the excitation information and the operating information using a fast Fourier transformation, prior to analyzing the excitation information and the operating information.

12. A device for determining a fluid conveying parameter of a fluid conveying device, comprising: a sensor for determining mechanical excitation information for at least one fluid conveying element of the fluid conveying device in at least one spatial direction, a provider for providing operating information, the operating information including at least a value of an operating variable of the fluid conveying device, a computing unit configured to analyze the mechanical excitation information and the operating information to determine a current working point of the fluid conveying device and configured to determine a fluid conveying parameter of the fluid conveying device based on the analyzed information, wherein the fluid conveying parameter comprises a volumetric flow, and wherein the computing unit comprises a memory configured to store at least one characteristic field for one or more operating variables of the fluid conveying device.

13. The device of claim 12, further comprising a closed-loop control unit which is configured to provide control signals for the fluid conveying device based on the fluid conveying parameter.

14. The device of claim 12, wherein the sensor comprises an oscillation sensor and/or the provider is configured to provide operating information of a controller.

15. A fluid conveying system, comprising a fluid conveying device having at least one fluid conveying element, and a device for determining a fluid conveying parameter of the fluid conveying device according to claim 12.

16. The fluid conveying system of claim 15, wherein the fluid conveying device comprises a fan and the fluid conveying element comprises an impeller.

Description

(1) Preferred designs and embodiments of the invention are shown in the drawings and will be explained in the description below, wherein like reference symbols refer to like or similar or functionally identical components or elements.

(2) Wherein

(3) FIG. 1 schematically shows a method according to an embodiment of the present invention;

(4) FIG. 2 shows a characteristic field of a radial fan according to an embodiment of the present invention, and

(5) FIG. 3 shows oscillation characteristics for various working points for the radial fan according to FIG. 2.

(6) FIG. 1 schematically shows a method according to an embodiment of the present invention.

(7) FIG. 1 provides oscillation information 4a and performance information 4b and matches it with a characteristic field 3b, starting from a rotational speed information 4c, for example of an impeller of a fan. The information 4a, 4b, 4c is then used to determine a characteristic line 3a, from which the volumetric flow 2 can be derived. In detail, for example, a characteristic line 3a is selected from the known characteristic field 3b of a radial fan depending on the rotational speed 4c, which is known in a motor electronics. Information about the performance 4b of the radial fan and along with it the rotational speed demand of the impeller of the radial fan is known from a control device of the radial fan. This information, in conjunction with the selected characteristic line 3a, is used based on the known impeller-specific correlation of oscillation excitation (oscillation information 4a) and volumetric flow to determine the current working point. The volumetric flow information determined in this manner can subsequently be used for closed-loop control of a constant volumetric flow, for example.

(8) FIG. 2 shows a characteristic field of a radial fan according to an embodiment of the present invention.

(9) In detail, FIG. 2 shows the characteristic field of a radial fan with backward curved blades. The performance 11 of the radial fan is plotted over the volumetric flow 10 for various rotational speeds n.sub.1, n.sub.2, . . . . The characteristic line (n.sub.1, n.sub.2, . . . ) drops on both sides starting from the respective maximum load point, that is towards lower or higher volumetric flows. If the respective motor or fan output is known, this results in two working points AP1 and AP2 which cannot be distinguished with respect to volumetric flow. The difference is due, among other things, to the system resistance and thus to the installation situation of the radial fan.

(10) FIG. 3 shows oscillation characteristics for various working points of the radial fan according to FIG. 2.

(11) In detail, FIG. 3 now shows the oscillation state present at the working points AP1 and AP2 mentioned in FIG. 2. This state results from the interaction of impeller and volumetric flow, which represents an exciting mass. When analyzing the oscillation information, a characteristic of the oscillation as a function of the individual impeller geometry is obtained, which correlates with the volumetric throughput of the impeller of the radial fan. For example, as shown in FIG. 3a, the time-dependent signal 13 of the oscillation sensor can be analyzed for the two working points AP1, AP2 with respect to its amplitude or signal variation 15. The signals 13, more precisely their variation, are clearly different for the two working points AP1, AP2. Alternatively, as shown in FIG. 3b, a signal analysis can be performed to identify characteristic frequency ranges 14 having signal peaks 16 for the two working points AP1, AP2. The oscillation characteristic can then be correlated with the respective volumetric flow.

(12) In summary, at least one of the embodiments of the present invention allows or provides one of the following features and/or at least one of the following advantages: A fan having a means for determining its operating state with respect to its output and rotational speed as well as a sensor for analyzing its mechanical oscillation behavior. A combination of performance data such as current, voltage, or other operational variables and information on mechanical excitation, such as oscillation amplitudes, oscillation rates, or a characteristic in the form of an oscillation spectrum for creating a defined operating point with respect to volumetric flow or pressure difference, taking into account known characteristic fields of the fan regarding speed-dependent output and volumetric flow. Currents, output, etc. can be used by a control device on the basis of signals of an oscillation sensor, particularly measured path changes x, y, z or, after their analysis using, for example, fast Fourier transformation or another signal evaluation method and using other known variables, to map a mass or volumetric flow. Determining a volumetric flow within the fan motor or its control/regulating device without additional measuring equipment, particularly volumetric flow, pressure or the like. Potential output of the information to a customer, for example, the volumetric flow as a user-side output parameter. The option of internal utilization in a controller for closed-loop control of the fan and/or for obtaining other operation-specific parameters, e.g. for its service life calculation.

(13) Although the present invention was described with reference to preferred embodiments, it is not limited to these and can be modified in manifold ways.

LIST OF REFERENCE SYMBOLS

(14) 2, 10 volumetric flow 3a characteristic line 3b characteristic field 4a oscillation information 4b performance information 4c rotational speed AP1, AP2 working point 11 output 12 time 13 path/elongation 14 frequency 15 difference max/min elongation 16 peaks