Sound emission device

Abstract

Sound emission device comprising a sound-emitting component (1), characterized in that the sound-emitting component (1) is arranged in a gas-filled, gas-tight envelope (2) wherein the gas has a speed of sound at least 10% greater than air.

Description

[0001] The invention relates to a sound emission device according to the preamble of claim 1.

[0002] A sound emission device of the type mentioned above is known from document EP 3 182 726 A1. This sound emission device consists (among other things) of a sound-emitting component. In the following, a sound emission device is particularly preferably understood to mean one in which the sound-emitting component is designed as part of a heat pump circuit, i.e., a component such as a compressor, an expansion device, a heat exchanger, or a pipe of the heat pump circuit.

[0003] The invention is based on the object of improving such a sound emission device. In particular, the low-frequency sound emission or radiation of such a sound emission device is to be reduced.

[0004] This object is achieved with a sound emission device of the type mentioned at the outset by the features listed in the characterising part of claim 1.

[0005] According to the invention, it is therefore provided that the sound-emitting component is arranged in a shell filled with a gas and sealed gas-tight to the outside, wherein the gas has a speed of sound that is at least 10% higher than that of air, in particular at a temperature in the range of 5°C to 30°C, particularly preferably at a temperature of 20°C.

[0006] In other words, the sound emission device according to the invention is characterized in that it, or at least its sound-emitting component, is encapsulated in a gas-filled enclosure, wherein the gas used is a gas with a speed of sound that differs significantly from that of air. This, as corresponding laboratory tests have shown, results in both the level (both inside and outside the enclosure) and the frequency spectrum of the sound emission (inside the enclosure) being specifically variable or alterable, particularly in the range above 400 Hz (below 400 Hz, the effectiveness is reduced due to structure-borne sound). As will be explained in more detail below, it is preferably provided that helium is used as the gas for filling the enclosure.

[0007] For the sake of completeness, it should be noted that the speed of sound multiplied by the density of the gas results in the so-called acoustic characteristic impedance (see also https: / / de.wikipedia.org / w / index.php?title=Schallkennimpedanz& oldid=230378957), ie ultimately the inventive requirement can also be defined accordingly via the acoustic characteristic impedance.

[0008] Other advantageous developments of the sound emission device according to the invention result from the dependent claims.

[0009] The sound emission device according to the invention, including its advantageous developments according to the dependent claims, is explained in more detail below with reference to the drawing of a preferred embodiment.

[0010] It shows schematically Fig.1 the sound emission device according to the invention with a sound emitting component arranged in a shell filled with a gas.

[0011] The sound emission device illustrated in the single figure comprises a sound-emitting component 1. It is preferably provided that the sound-emitting component 1 is designed as part of a heat pump circuit (not separately illustrated), in particular as a compressor, of a heat pump. Furthermore, it is particularly preferably provided that the sound-emitting component 1 is designed to conduct a refrigerant, preferably propane (also called R290). Furthermore, it is preferably provided that the heat pump circuit, in particular its heat exchanger, is fluidically connected to a heating circuit via elastic hoses, in particular EPDM hoses.

[0012] What is essential for the sound emission device according to the invention is that the sound-emitting component 1 is arranged, and thus encapsulated, in a shell 2 filled with a gas and sealed gas-tight to the outside. The gas has a speed of sound that is at least 10% higher than air (in this case 343 m / s), particularly at a temperature in the range from 5°C to 30°C, particularly preferably at a temperature of 20°C. It is particularly preferably provided that the gas has a speed of sound that is at least 25%, particularly preferably 200% higher than air, particularly at a temperature in the range from 5°C to 30°C, particularly preferably at a temperature of 20°C. The noble gas helium, which has a speed of sound of 981 m / s at 20°C, is very particularly preferably provided as the gas.This approach results in a higher absorption effect and thus greater sound reduction, especially because the sound waves pass through the absorption material much more frequently due to the higher speed of sound.

[0013] Furthermore, it is preferably provided that, in order to influence the (above-mentioned) acoustic characteristic impedance of the gas, this (i.e., the gas), in particular at a temperature in the range of 5°C to 30°C, particularly preferably at a temperature of 20°C, has a density that is at least 10% greater than the air surrounding the casing 2. Said density can be influenced accordingly via the gas filling quantity or the pressure of the gas in the casing 2. Particularly preferably, the acoustic characteristic impedance of the gas in the casing 2 is lower than that of the surrounding air.

[0014] Furthermore, it is particularly preferred that the outwardly gas-tight casing 2 be designed either as a bubble shaped by the gas or as a solid housing. Thus, the casing 2 can be designed either as an inflated balloon or as a dimensionally stable, appropriately sealed (with respect to the gas used) housing, particularly preferably with a stiffened base plate.

[0015] Furthermore, it is preferably provided that an optionally electrical or fluidic line of the sound-emitting component 1 is guided through a wall of the casing 2 in a lower region. Especially when using helium, this provision has the advantage that the gas accumulating at the top of the casing 2—because it is lighter than air—is not lost through the sealing point(s) around the line(s). Expressed somewhat more generally, in this context, it is further preferably provided that a casing sealing device (not separately shown) is arranged in a lower region of the casing 2.

[0016] In the event that, for example, the temperature of the sound-emitting component 1 should change during operation of the sound emission device, a gas pressure equalization chamber 3 which can be optionally connected or is connected to the casing 2 is also provided to compensate for possible volume changes of the gas within the casing 2.

[0017] In the event that the casing 2 should, for example, exhibit an unwanted leak, an additional reservoir 4 filled with gas and connectable to the casing 2 is provided for any necessary refilling of the casing 2. Furthermore, a sensor device 5 is preferably provided for detecting a loss of gas from the casing 2. Furthermore, an actuating device 6 is also provided, which is connected to the additional reservoir 4 and the sensor device 5 and preferably automatically compensates for any gas loss that may occur, in particular, optionally during the service life of the device or during a maintenance interval.

[0018] With specific reference to a heat pump, the solution according to the invention can finally be explained as follows: As a result of the low-frequency tonal sound radiation from compressors, a so-called modal sound field forms within a typical heat pump casing, i.e., within the shell 2, in a specific frequency range, which has a sound-amplifying effect. These are standing waves within the shell 2, the frequency range of which depends on the dimensions of the shell 2 and the speed of sound of the gas. Within the shell 2, a certain internal sound level develops, the propagation of which is reduced by the airborne sound insulation of the shell 2. The sound insulation of such a single-shell shell increases with increasing mass and frequency.

[0019] The inventive solution is characterized by changing the gas within the shell, thereby influencing both the sound radiation and the characteristics of the modal sound field, as well as the airborne sound insulation. Of particular technical interest here are the aforementioned media properties of the speed of sound and the characteristic sound impedance (product of the speed of sound and density). Increasing the speed of sound has a particularly beneficial effect, as it shifts the airborne sound radiation and the modal sound field into a higher frequency range. In addition, sound insulation is also increased without the need for additional measures. The detuning of the speed of sound can be achieved using various gases.As explained above, the inert gas helium is of particular technical interest, particularly because it causes a massive increase in the speed of sound and also fulfils a safety function, namely the prevention of a potentially explosive atmosphere in the event of propane escaping from the refrigerant circuit (leakage). List of reference symbols 1 sound-emitting component 2 Cover 3 Gas pressure equalization chamber 4 Additional reservoir 5 Sensor device 6 Actuating device QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 3 182 726 A1

[0002] Cited non-patent literature

[0000] https: / / de.wikipedia.org / w / index.php?title=Sound impedance& oldid=230378957

[0007]

Claims

[1] Acoustic emission device comprising a sound-emitting component (1), characterized by that the sound-emitting component (1) is arranged in a gas-filled casing (2) which is sealed gas-tight to the outside, the gas having a sound speed at least 10% higher than air. [2] Acoustic emission device according to claim 1, characterized by that the gas has a density at least 10% greater than the air in the vicinity of the envelope (2). [3] Acoustic emission device according to claim 1 or 2, characterized by that the sound-emitting component (1) is designed as part of a heat pump circuit of a heat pump. [4] Acoustic emission device according to one of claims 1 to 3, characterized by that the outwardly gas-tight envelope (2) is designed either as a bubble shaped by the gas or as a solid housing. [5] Acoustic emission device according to one of claims 1 to 4, characterized by that an optionally electrical or fluidic line of the sound-emitting component (1) is guided at a lower region through a wall of the casing (2). [6] Acoustic emission device according to one of claims 1 to 5, characterized by that a gas pressure compensation chamber (3) is provided which can be optionally connected or is connected to the casing (2) to compensate for possible volume changes of the gas within the casing (2). [7] Acoustic emission device according to one of claims 1 to 6, characterized by that an additional reservoir (4) filled with the gas and connectable to the casing (2) is provided for any necessary refilling of the casing (2). [8] Acoustic emission device according to one of claims 1 to 7, characterized by that a sensor device (5) is provided for detecting a loss of gas from the casing (2). [9] Acoustic emission device according to one of claims 1 to 8, characterized by that helium is intended as the gas. [10] Acoustic emission device according to one of claims 1 to 9, characterized by that the sound-emitting component (1) is designed to carry a refrigerant, preferably propane.

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