Method for operating a variable speed circulation pump and circulation pump for carrying out the method

Abstract

The present invention relates to a method for operating a variable speed circulation pump, in particular a heating circulation pump, in which a pump controller detects at least one physical pump operating variable by means of a sensor and compares it indirectly or directly with at least one stored reference value in order to evaluate the installation position of the pump.

Description

[Technical Field]

[0001] The present invention relates to a method for operating a variable speed circulation pump, particularly a heating circulation pump. [Background technology]

[0002] The acoustic characteristics of a heating circulation pump play an important role in the purchase decision. In the most unfavorable cases, excessive noise production by the pipeline system can be transmitted into the living space, which is perceived as an annoyance by the end user. Furthermore, excessive noise emissions from a circulation pump represent a significant competitive disadvantage.

[0003] The cause of excessively high noise levels during pump operation can be the pump itself or the selected installation variant of the pump in the heating circuit. For a typical circulation pump, several different installation variants are possible, allowing for greater flexibility in terms of the installation situation and spatial relationship. However, it is almost impossible for the installer to identify in advance which installation variant is optimal in terms of operating noise. In the most unfavorable case, the pump's operating vibrations coincide with the natural frequency of the system consisting of the pump and pipeline, resulting in a noticeable increase in noise emissions. In this case, the problem can be addressed by changing the installation variant. Summary of the Invention

[0004] In this context, automatic detection of non-optimal installation variants is desirable.It is therefore an object of the present invention to present a method for detecting non-preferred installation variants.

[0005] This object is achieved by a method according to the features of claim 1. Advantageous features of this method are the subject matter of the dependent claims.

[0006] According to the present invention, it is proposed to extend the pump controller with a suitable routine for detecting unfavorable installation variants for variable-speed circulation pumps, particularly heating circulation pumps, by detecting at least one physical operating variable of the pump via a sensor and comparing it directly or indirectly with at least one stored reference value. The results of the comparison can be used to evaluate the installation variant, particularly with regard to whether the installation variant is unfavorable in terms of noise emissions during operation of the pump. Circulation pumps are typically centrifugal pumps.

[0007] In this case, there is the possibility of a direct comparison, in which the measured physical operating quantities of the pump are directly compared with corresponding reference quantities. An indirect comparison encompasses embodiments in which the measured quantities are first subjected to further processing, and at least one quantity derived therefrom is compared with a suitable reference quantity.

[0008] Physical quantities that can characterize the pump's behavior, i.e., its noise emissions, are suitable as pump operating quantities. The introduction already pointed out the negative effects that can lead to unpredictable increases in noise emissions, particularly if the pump's operating vibrations coincide with the natural frequency of the system consisting of the pump and the pipeline. Therefore, physical quantities that allow assertions about the pump's operating vibrations are particularly suitable. Specific examples include determining acceleration values, in particular the acceleration of the conveyed medium and / or the acceleration of the driving pump impeller and / or the acceleration of the pump casing. Acceleration values should be captured as close as possible to the impeller. Acceleration values can be measured by an integrated acceleration sensor associated with the circulation pump, which is preferentially attached to the pump casing in the immediate vicinity of the impeller.

[0009] The measurement capture of the physical operating quantities of the pump being used may be continuous while the pump is operating, or may be limited to a definable measurement interval with repeated measurements at random or regular intervals.

[0010] If there is a deviation of the measured operating quantity of the pump from the corresponding assigned reference value, particularly if the deviation occurs by a definable amount, the pump controller may provide visual and / or acoustic cues to draw the end user's or installer's attention to the problematic nature of the installation variant, ideally in combination with the suggestion of a better alternative installation variant.

[0011] It is also conceivable that the captured values of the pump's operating quantity are first subjected to further processing. In particular, the vibration behavior of the physical operating quantity is considered to be ascertained based on the measured physical operating quantity of the pump. For this purpose, the pump's operating quantity needs to be captured over a certain period of time so that the vibration behavior of that quantity can ultimately be inferred. The vibration behavior is obtained from the time progression of the measured acceleration values, for example by means of a fast Fourier transform (FFT).

[0012] In this regard, it is also conceivable that at least one quantity characterizing the identified vibration behavior is compared with a suitable reference value of the characteristic quantity stored in the pump controller to evaluate the installation variant. To characterize the quantity, the amplitude and / or frequency of the identified vibrations are appropriately suggested. In this regard, it is particularly preferable to compare the vibration amplitude with a reference amplitude, and if the captured amplitude is greater than the reference amplitude by a specified amount, a signal is sent to the end user regarding a non-optimal installation variant.

[0013] According to a further preferred embodiment of the invention, the reference value can depend on the current operating point of the pump. The current operating point of the circulation pump is defined by the intersection of the pump's plant characteristic and its control characteristic. Since the noise generated by the pump is highly dependent on the selected operating point, an advantageous embodiment of the method proposes defining individual reference values assigned to multiple operating points and storing them in a ready state in the pump controller. The pump controller selects the appropriate reference value as a function of the currently adjusted operating point and compares the current measurement value with the selected reference value indirectly or directly.

[0014] Ideally, one or more suitable reference values are generated in advance during pump development. For this purpose, a reference pump is used in different installation variants in the test environment. For each installation variant, reference quantities are measured and saved for different operating points. The reference value of the installation variant that represents the lowest noise emission in the test rig is then selected as the final reference value.

[0015] In addition to the method according to the invention, the object is also achieved by a circulation pump, in particular a heating circulation pump, which is provided with a variable speed pump drive and a pump controller suitable for carrying out the method according to the invention. The circulation pump thus has the same advantages and properties as those already described in detail above with reference to the method according to the invention, and therefore will not be repeated. The circulation pump is typically a centrifugal pump.

[0016] According to an advantageous practical embodiment, the pump may preferentially include at least one acceleration sensor, further sensors allowing indirect capture of acceleration values are also conceivable.

[0017] Further advantages and features of the present invention are explained in more detail below with reference to specific embodiments. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2 is a schematic diagram showing the installation state of a circulation pump. [Figure 2] FIG. 10 is a signal diagram of captured acceleration values. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention describes a method for detecting undesirable installation variants of a heating circulation pump 10. The method is implemented in a pump controller and presupposes that the pump 10 is equipped with an acceleration sensor 11 that captures the acceleration of the pump casing as close as possible to the pump impeller. The pump structure is shown diagrammatically in Figure 1.

[0020] 1 also shows a schematic mounting of a circulating pump 10 to a building wall 1. The mounting location is represented herein as a spring / damper system 12. The type of mounting affects the stiffness and damper parameters, which in turn change the natural frequency and associated amplitude.

[0021] The actual realization of the process is based on two preparatory steps. In the first preparatory step, the optimal installation variant is defined. For this purpose, during the development phase, different installation variants are operated in a test environment and in each instance the vibration behavior and acoustics are captured at several operating points.

[0022] In a second preparatory step, one of the variants is evaluated as optimal based on the measurement data. In this variant, the characteristic values detected by the acceleration sensor 11 are stored in a matrix to describe the vibration state (e.g., amplitude, frequency) at several operating points. The vibration state, i.e., the amplitude / frequency diagram of the vibration behavior, is obtained from the time progression of the measured acceleration values by means of a fast Fourier transform.

[0023] This data is then stored in the pump controller's local memory. The method according to the present invention is then implemented while the pump is in operation. Using the acceleration sensor 11, the pump 10 captures the acceleration of the pump casing over time. Using a fast Fourier transform, characteristic vibration values are determined and compared with previously determined optimal reference values. If the vibration amplitude during this process is significantly greater than the previously determined optimal amplitude, the pump 10 detects this and notifies the user. The user can use this information to optimize the installation variant of the pump 10, if necessary.

[0024] An example of the vibration behavior of different installation variants is shown in Figure 2. Figure 2 shows the frequency / amplitude diagrams ascertained by FFT from the signal progression of the accelerometer 11 for two different installation variants. Installation variant 2 shows clearly lower vibration amplitudes at certain frequencies than installation variant 1. Here, it is possible to identify the influence of the stiffness and damping parameters of the respective installation variants (according to Figure 1) shown in Figure 1 on the frequency response of the measurements captured by the accelerometer during operation.

Claims

1. A method for operating a heating circulation pump, comprising: The pump controller captures the acceleration of the vibration of the heating circulation pump by at least one acceleration sensor provided on the heating circulation pump while the heating circulation pump is installed at the installation position and the heating circulation pump is operating, in order to evaluate the installation position of the heating circulation pump; the pump controller indirectly compares the acceleration of the vibration captured by the acceleration sensor with at least one reference value stored in the controller, the reference value being a feature for evaluating the installation position that was set before the heating circulation pump was installed at the installation position; The pump controller calculates a vibration behavior of the heating circulation pump from the acceleration measured at a predetermined time of the heating circulation pump by a fast Fourier transform; The vibration behavior is compared with the reference value, and if there is a deviation of the vibration behavior from the reference value, a visual or acoustic cue is issued by the pump controller to draw the user's attention to a non-optimal installation position.

2. 2. The method of claim 1, wherein the acceleration of the heating circulation pump is captured continuously or periodically or within a definable measurement interval.

3. 2. The method of claim 1, wherein the quantities characterizing the vibration behavior include the amplitude and / or frequency of the vibrations.

4. the reference value includes a vibration amplitude value comparable to the amplitude of the vibration; 4. The method of claim 3, wherein the amplitude of the vibration is compared to the vibration amplitude value, and the signaling occurs if the amplitude is greater than the vibration amplitude value by a specified amount.

5. A heating circulation pump comprising a variable speed pump drive and a pump controller for carrying out the method according to any one of claims 1 to 4, including at least one acceleration sensor.

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