DEVICE AND METHOD FOR ACTIVELY REDUCING PRESSURE VARIATIONS IN A HYDRODYNAMIC SYSTEM

Abstract

The invention relates to a device for active reduction of pressure fluctuations in a hydrodynamic system comprising a pump, a pressure fluctuation generator and at least one pressure sensor, and a controller unit. The controller unit is adapted to control the pressure fluctuation generator and to receive a pressure fluctuation signal from the pressure sensor. Furthermore, the present invention relates to a corresponding method and a pressure fluctuation generator for a corresponding device.

Claims

1-10. (canceled)

11. A device for active reduction of pressure fluctuations in a hydrodynamic system comprising: a pump, a pressure fluctuation generator, at least one pressure sensor and a controller unit, wherein the controller unit is adapted to control the pressure fluctuation generator and receive a pressure fluctuation signal from the pressure sensor, wherein the rotational speed of the pump can be captured and is receivable by the controller unit, wherein the controller unit is adapted to to generate a reference signal from the rotational speed of the pump, generate a control signal from the reference signal by means of an adaptive filter, and to control the pressure fluctuation generator with the control signal, wherein the controller unit is adapted to continuously optimize the adaptive filter to minimize the pressure fluctuation signal.

12. The device according to claim 11, wherein the pump comprises a constant number of blades, wherein the controller unit is adapted to generate a reference signal comprising a first amplitude peak at a first frequency corresponding to the rotational speed multiplied by the number of blades.

13. The device according to claim 12, wherein the controller unit is adapted to generate a reference signal comprising, in addition to the first amplitude peak at the first frequency, at least one further amplitude peak at a further frequency, wherein the at least one further frequency corresponds to an integer multiple of the first frequency.

14. A pressure fluctuation generator for generating pressure fluctuations in a hydrodynamic system, comprising: an oscillator and an actuator, wherein the oscillator comprises a source area facing a pressure compartment of the hydrodynamic system and to which a static pressure of the hydrodynamic system is applied, wherein the oscillator is connected to the actuator, wherein the actuator is adapted to oscillate the source area by means of a control signal to apply pressure fluctuations to the hydrodynamic system, wherein the pressure fluctuation generator comprises a back pressure chamber separated from the pressure compartment of the hydrodynamic system and from the ambient pressure, and the oscillator faces the back pressure chamber at backside of the source area, wherein the back pressure chamber is gas-filled and a back pressure is present in the back pressure chamber which is matched to the static pressure in the pressure compartment.

15. The pressure fluctuation generator according to claim 14, wherein the oscillator is a piston.

16. The pressure fluctuation generator according to claim 14, wherein the oscillator is a diaphragm.

17. The pressure fluctuation generator according to claim 14, wherein the actuator is a Lorentz actuator.

18. The pressure fluctuation generator according to claim 14, wherein the actuator is a piezoelectric actuator.

19. A method for active reduction of pressure fluctuations in a hydrodynamic system by means of a device according to claim 11, wherein the controller unit receives a pressure fluctuation signal from the pressure sensor, wherein the rotational speed of the pump is captured and received by the controller unit, wherein the controller unit generates a reference signal from the rotational speed of the pump, wherein the controller unit generates a control signal from the reference signal by means of an adaptive filter, and controls the pressure fluctuation generator with the control signal, wherein the controller unit continuously optimizes the adaptive filter to minimize the pressure fluctuation signal.

20. The method according to claim 19, comprising the use of a pressure fluctuation generator for generating pressure fluctuations in a hydrodynamic system, comprising: an oscillator and an actuator, wherein the oscillator comprises a source area facing a pressure compartment of the hydrodynamic system and to which a static pressure of the hydrodynamic system is applied, wherein the oscillator is connected to the actuator, wherein the actuator is adapted to oscillate the source area by means of a control signal to apply pressure fluctuations to the hydrodynamic system, wherein the pressure fluctuation generator comprises a back pressure chamber separated from the pressure compartment of the hydrodynamic system and from the ambient pressure, and the oscillator faces the back pressure chamber at backside of the source area, wherein the back pressure chamber is gas-filled and a back pressure is present in the back pressure chamber which is matched to the static pressure in the pressure compartment; wherein a respective pressure sensor measures the static pressure in the hydrodynamic system and in the back pressure chamber, wherein the controller unit controls at least one valve connected to the back pressure chamber and adjusts the back pressure in the back pressure chamber to the static pressure in the hydrodynamic system.

Description

[0043] The invention is explained below with reference to preferred embodiments with reference to the accompanying figures. Thereby shows

[0044] FIG. 1 a schematic illustration of a device for active reduction of pressure fluctuations in a hydrodynamic system; and

[0045] FIG. 2 a pressure fluctuation generator.

[0046] FIG. 1 shows an embodiment of a device 1 for active reduction of pressure fluctuations in a hydrodynamic system in a schematic illustration. Hydrodynamic systems can be open or closed, wherein only the zone between a pump 2 and a hydrodynamic component 9 is shown in the schematic illustration of FIG. 1. Therefore, the hydrodynamic system of the embodiment, in which the device 1 for active reduction of pressure fluctuations is integrated, can be either an open or a closed hydrodynamic system. The hydrodynamic component 9 may be one or more hydraulic elements, such as valves, hydraulic actuators, heating bodies, thermostats, etc., which are connected to the pump 2 via pipes 3. The pump 2 generates a static pressure in the hydrodynamic system as well as, depending on the hydrodynamic component 9, a volume flow with a flow direction 8. The hydrodynamic system can be, for example, the heating circuit of a residential building.

[0047] Pressure fluctuations are introduced into a hydrodynamic system, in particular by a pump 2, which propagate in the hydrodynamic system and excite the structure, in particular the pipes 3, to vibrate. Among other things, this can lead to undesirable acoustic emissions.

[0048] The device 1 for active reduction of pressure fluctuations comprises a pressure fluctuation generator 10, which selectively introduces pressure fluctuations into the hydrodynamic system to destructively interfere with the existing pressure fluctuations generated by the pump 2 and/or the hydrodynamic component 9.

[0049] The pressure fluctuation generator 10 is therefore hydraulically or hydrodynamically connected to the hydrodynamic system, which in the embodiment of FIG. 1 is done by means of a Y-shaped connecting piece 16.

[0050] Downstream of the connecting piece 16, a pressure sensor 4 is arranged on the pipe 3, which can capture the pressure fluctuations and thus temporally resolve the pressure in the pipe 3 of the hydrodynamic system accordingly. The pressure fluctuations are transmitted from the pressure sensor 4 as a pressure fluctuation signal 6 to a controller unit 5.

[0051] The controller unit 5 receives the rotational speed of the pump 2, which is captured by means of a rotational speed sensor. In this embodiment, the pump 2 comprises a number of blades of seven and an assumed rotational speed of 1450 revolutions per minute. The controller unit 5 captures the rotational speed, multiplies the rotational speed by the set number of blades and generates from this a sinusoidal reference signal with 169.2 Hz, which corresponds to the first blade passing frequency. Phase position and amplitude of the sinusoidal reference signal can have preset values in the controller unit 5.

[0052] In this advantageous embodiment, in addition to the first blade passing frequency, the second and third blade passing frequencies are also taken into account in the reference signal. Accordingly, further sinusoidal oscillations at 338.4 Hz and 676.8 Hz are modulated into the reference signal. Phase position and amplitude of the higher reference signal can have preset values in the controller unit 5, wherein the amplitude for the second and third blade passing frequency in the reference signal is preferably lower than the amplitude of the first blade passing frequency.

[0053] An adaptive finite impulse response filter is implemented in the controller unit 5, which filters the reference signal. The filtered reference signal is fed as a control signal 7 to a pressure fluctuation generator 10, which is controlled accordingly.

[0054] The pressure fluctuation generator 10 generates pressure fluctuations or pressure pulses which, starting from the source area 13, see also FIG. 2, propagate in the pressure compartment 14 along the wall of the pipe 3 and interfere in the connecting piece 16 with the pressure fluctuations in the hydrodynamic system, in particular with the pressure fluctuations induced by the pump 2.

[0055] The resulting pressure fluctuations are in turn captured by the pressure sensor 4 and transmitted to the controller unit 5 as a pressure fluctuation signal 6, thus providing feedback on the action of the pressure fluctuation generator 10. A continuous minimization process is performed in the controller unit 5, which minimizes the pressure fluctuation signal 6 as a target variable by varying the filter parameters of the digital adaptive FIR filter in the controller unit 5. Consequently, the filter parameters are varied according to the minimization process after a time interval has elapsed and the result is evaluated as the pressure fluctuation signal 6. Furthermore, the continuous optimization of the adaptive filter enables adaptation to the changes in the hydrodynamic system in which the device 1 is used for active reduction of pressure fluctuations. The changes in the filtering behavior of the adaptive filter is used, among other things, to adjust the phase and amplitude of the counter-pressure or pressure fluctuations generated by the pressure fluctuation generator 10. In possible alternative embodiments, the filter parameters may be fixed after an optimization phase.

[0056] Changes in or to the hydrodynamic system have a direct effect on the operational behavior of the pump 2 and thus on the pressure fluctuations it generates. Changes are, for example, the connection and disconnection of serial or parallel pipe lines with the hydrodynamic components 9 (e.g. heating bodies on or off) as well as their targeted throttling by adjusting the valve position. As a result of the changing system behavior of the hydrodynamic system, a permanent identification of the circuit and adaptation of the control parameters in the controller unit 5 for the actuator 12 is particularly advantageous, which is achieved by the adaptive filter and the optimization process.

[0057] Furthermore, in possible embodiments, further pressure sensors 4′ can optionally be used along a section of the pipe 3, which determine the direction of superimposed, counterpropagating pressure waves in the controller unit 5, so that the propagation directions of the pressure fluctuation components can be separated in a signal processor of the controller unit 5.

[0058] FIG. 2 shows an embodiment of a pressure fluctuation generator 10, which is also used in the embodiment of the device for active reduction of pressure fluctuations of FIG. 1.

[0059] The pressure fluctuation generator 10 comprises an oscillator 11 in the form of a piston or piston radiator, the end face of which, as a source area 13 in a connection pipe, points into the pressure compartment 14 in which the static pressure of the hydrodynamic system is applied. The connecting pipe leads into a y-shaped connecting piece 16, which can be inserted into the pipes 3 of a hydrodynamic system. The oscillator 11 is driven by an actuator 12, which in this embodiment is a Lorentz actuator and performs a control of the oscillator 11 by the control signal 7 using the Lorentz force. In possible embodiments, a transmission element may be used when a Lorentz actuator is used as an actuator 12.

[0060] The pressure fluctuation generator 10 comprises a back pressure chamber 15, which causes a static back pressure on the back side of the source area 13 exposed to the pressure compartment 14 and thus to the static pressure of the hydrodynamic system. The back pressure in the back pressure chamber thus balances the static pressure of the hydrodynamic system. In this way, the oscillator 11 can effectively generate pressure fluctuations and the actuator 12 is not loaded by a force of static pressure on the source area 13. The back pressure chamber 15 is filled with gas, preferably nitrogen, for ease of compression and expansion as the oscillator 11 displaces.

[0061] In this advantageous embodiment, the back pressure in the back pressure chamber 15 is adjusted to the static pressure of the hydrodynamic system or the static pressure in the pressure compartment 14, wherein the static pressure can be captured by means of a pressure sensor 4 and/or 4′ and can be tracked by the controller unit 5 by actuating corresponding valves, not shown. Accordingly, a piston emitter may, for example, be a cylinder in which a displaceable piston is mounted in a force-neutral manner as an oscillator 11 and is driven in a defined manner, for example, by means of a piezo element and/or a Lorenz actuator as an actuator 12.

[0062] When a piezo element is used as actuator 12, in possible embodiments a transmission element may be provided which operates according to the principle of the hydraulic transmission ratio.