Method and device for estimating the noise generation of a complex apparatus, in particular an inspection machine

Abstract

The invention relates to a method for estimating the noise generation of a complex apparatus, in particular an inspection machine, which has at least two noise-producing components (104, 106, 108, 114, 116, 118), wherein a total value of a physical variable is determined, which total value describes the noise generation of the complex apparatus (100), in particular a total value of the sound power or of the sound pressure. According to the invention, for each of the at least two noise-producing components (104, 106, 108, 114, 116, 118), at least one component value of the physical variable is provided, said component value describing the noise generation of the particular noise-producing component (104, 106, 108, 114, 116, 118), and the total value for the complex apparatus (100) is determined from component values for the at least two noise-producing components (104, 106, 108, 114, 116, 118). The invention also relates to a device for carrying out or implementing the method and to a complex apparatus having a device of this type.

Description

[0001] Method and device for estimating the noise generation of a complex device, in particular an inspection machine

[0002] The invention relates to a method for estimating the noise development of a complex device, in particular an inspection machine, having the features of the preamble of patent claim 1. Furthermore, the invention relates to a device for carrying out the method according to patent claim 12 and to a complex device having such a device according to claim 16.

[0003] Occupational health and safety requires compliance with specified safety standards. This includes protection against excessive noise exposure in the workplace. Various national and international regulations define noise limits and noise measurement methods for this purpose.

[0004] It should be noted at this point that the term "noise" will be used in the following instead of the term "noise," which is primarily used to describe sounds perceived as unpleasant. This is because health impairments, such as hearing damage, occur regardless of whether the respective sound is perceived as pleasant or unpleasant.

[0005] Most measurement methods for recording the noise generated by a device require a high level of metrological effort. For example, if the noise generated by a larger device, such as an inspection machine, is to be assessed, the noise generated must be measured at 10 or more measuring locations in the vicinity of the device, depending on the regulations to be observed and any prescribed measuring procedure. In most cases, the measurement result, which is generated by linking the measured values ​​at the measuring locations, must be determined as a "two-value number", which consists, on the one hand, of an absolute value of a quantity characterising the noise generated by the device and, on the other hand, of a value characterising the measurement uncertainty. Such noise measurements must be carried out either in special, soundproof laboratories orrooms or they can only be carried out when the environment is quiet enough, for example at night or at times when no disturbing noise is generated in the environment.

[0006] Certain regulations require the assessment of a device's noise emissions at different times or in different phases of its development and life cycle. For example, it may be necessary to determine the noise emissions of a complex device comprising multiple noise-generating components during the development phase or after the complex device has been assembled in the manufacturing plant.

[0007] These requirements make it clear that carrying out the measurements to determine a value or a two-value number to characterise the noise development of a complex machine involves a correspondingly high level of effort.

[0008] The invention is therefore based on the object of creating a method for estimating the noise generation of a complex device, in particular an inspection machine, and a device that enables the noise generation of a complex device comprising several noise-generating components to be estimated as simply and as inexpensively as possible. Furthermore, the invention is based on the object of creating a complex device with such a device.

[0009] The invention solves this problem with the features of patent claims 1 and 12 and 16. Further embodiments of the invention emerge from the respective dependent claims.

[0010] The invention is based on the finding that a total value of a quantity characterizing the noise generation of a complex device can be estimated using component values ​​for a physical quantity, each of which characterizes the noise generation of the respective noise-generating components. This can be done, in particular, using a total value for the sound power and / or the sound pressure or corresponding level values ​​(i.e., by specifying a value for the logarithm of the value for the sound power or the sound pressure referred to a standard value multiplied by 10).

[0011] The complex device may, for example, be an inspection machine comprising several conveyor belts, ejector devices (for example ejector devices comprising blowing nozzles) and, if appropriate, other noise-generating components.

[0012] As a physical quantity that describes the noise generated by a complex device or its noise-generating components, sound power and / or sound pressure can be used. The sound power Pak is an acoustic quantity that describes the sound energy emitted by a sound source per unit of time. Sound power is usually expressed on a logarithmic scale as the sound power level L. w specified, where:

[0013] L w = lO log^ dB, "o with the reference value Po=1O standardized for airborne sound -12W. The sound power or sound power level can also be determined from sound pressure measurements according to DIN EN ISO 3746:2011-03. The starting point for this is the measurement of the sound pressure levels at specified positions on an enveloping surface. This type of measurement of the sound power or sound power level is an emission measurement, in which the total sound energy emitted by the device is measured.

[0014] Furthermore, the sound pressure level L can be used as a parameter characterising the noise development of a complex device. p used in a specific location, such as the workplace. This represents a measure of the sound pressure level generated by the machine at that location, excluding the influence of the room (which can cause reflections, for example) and the influence of extraneous noise. The sound pressure level L presults from the logarithmic ratio of the squares of the sound pressure p and the reference value po=2 1O' 5 Pa according to: 2 ö

[0015] L„ = 10 log - 7 dB = 20 log - dB Po Po

[0016] This is an immission measurement in which the influence of a sound source on a specific location is determined, in particular by measuring the sound pressure at the location in question.

[0017] According to the invention, a method is provided in which the noise development of a complex device having two or more noise-generating components can be estimated by providing, for each noise-generating component, a component value of the variable describing the noise development of the respective component. The total value of the variable characterizing the noise development of the complex device is determined according to the invention from the component values ​​for the plurality of noise-generating components. At this point, it should be mentioned that a complex device can of course also comprise noise-generating components that are not used for the method according to the invention. The phrase "each noise-generating component" is therefore to be understood as "each relevant noise-generating component to be taken into account within the meaning of the invention).

[0018] If the sound power of a complex device is to be determined, i.e., the sound energy emitted per unit of time through a closed enveloping surface surrounding the device, this can be done by summing the sound power levels measured or determined individually for each of the noise-generating components (especially in a state detached from the complex device). This only represents an estimate of the sound power, since, for example, absorption of the sound power generated by the components by other components or parts of the complex device and influences of the assembly of the components within the complex device (e.g., changes in the resonance conditions of the components) are neglected.

[0019] A similar approach can, of course, also be used in the case where the influence of the sound power emitted by the complex device at a specific location is to be measured. In this case, however, the distance of the respective measurement location from the complex device, in particular from each of the noise-generating components, must be taken into account. For example, one can assume, as an approximation, that the sound pressure decreases inversely proportional to the distance from the sound source.

[0020] In this approximation, both in the case of determining the sound power and in the case of determining the sound pressure at a specific measuring location, the influence of the noise-generating components and the influence of other (non-noise-generating) components of the complex device are of course not taken into account, in particular their damping properties and also their resonance properties, which can lead to the generation of noise, in particular vibration noise, even in the case of non-noise-generating components.

[0021] Nevertheless, the method according to the invention makes it possible to obtain at least an estimate of a quantity characterising the noise generation, such as the sound power or the sound power level or the sound pressure or the sound pressure level at a given measuring location, even before the components of a complex device are assembled.

[0022] If a specified limit for the total value is exceeded, a warning signal can be generated. Additional or alternative actions can be performed. For example, other components or component types can be selected to implement the complex device, or operating parameters can be changed.

[0023] In any case, according to the invention, at least one component value for the respective acoustic quantity is provided for each noise-generating component. This provision can be achieved by measuring the relevant component value for each specific noise-generating component. As already explained above, the measurement can be carried out, in particular, independently of the other components of the complex device. This can already occur during production of the component. According to a further embodiment, instead of determining such a measured component value for each specific component, a type component value can be used. Such a type component value can be determined, for example, by determining a measured component value for a predetermined plurality of identically constructed noise-generating components and averaging the relevant plurality of measured component values.The latter approach is particularly suitable in cases where the identical noise-generating components exhibit a relatively small scatter with regard to the acoustic quantity characterizing the noise generation.

[0024] According to one embodiment of the invention, the measured component values ​​or the type component values ​​can be assigned to the respective component or component type, or stored in a database in such a way that they can be assigned. For example, a serial number, a type designation, or any other characteristic of a noise-generating component or a type of noise-generating component can be used as an assignment feature. However, the assignment can also be made in another way, for example, through the order or another arrangement of the relevant values ​​in the database.

[0025] However, the component values ​​(measurement component values ​​or type component values) can of course also be stored in the respective component or provided on or in a readable, preferably machine-readable, manner. An evaluation unit can read the component values ​​from the memory. A suitable scanning device can be used to read the at least one component value provided on or in the component.

[0026] A noise-generating component can have one or more operating states, with each operating state being assigned at least one component value or at least one component value of an operating state being determined from one or more component values ​​of other operating states, for example by extrapolation, interpolation, or other calculation rules. Each operating state of a component can be defined by values ​​for one or more operating variables or operating parameters. For example, an operating state for a specific conveyor belt or a specific conveyor belt type can be defined by a component value that results for a specific drive speed. In this case, the component value depends in particular on the geometry and nature of the conveyor belt, the nature of the drive motor, and the drive speed.

[0027] The complex device can have one or more operating states, and for each of these operating states, an overall value can be determined. At least one operating state of each of the noise-generating components is assigned to each operating state of the complex device. Thus, for each operating state of the complex device, an overall value can be determined from the component values ​​for the respectively assigned operating states of the noise-generating components.

[0028] This method can also be used to estimate the noise generated by the complex device in each operating state, depending on one or more planned operating states of the complex device. If it turns out that the noise generated is too high in one or more operating states, this operating state can either be avoided or excluded, or the complex machine can be implemented with one or more other components or component types in such a way that this modified complex device has a total value that does not exceed a specified limit in every operating state.

[0029] According to one embodiment of the invention, the maximum overall value across all (fundamentally possible) operating states can be used to describe or characterize the noise generation of the complex device. A design change, in particular the use of one or more other noise-generating components or component types, can be implemented if a predetermined limit for the overall value is exceeded. Alternatively, of course, those (fundamentally possible) operating states for which the maximum overall value is exceeded can also be avoided.According to a further embodiment, the method according to the invention can be applied during the operation of the complex device, wherein the total value is determined for a current operating state or for a planned changed operating state and wherein an action is triggered, in particular a signal is generated, when the determined total value exceeds a predetermined limit value.

[0030] This allows an estimate of the total value to be made even when a current operating state of the complex device is present (e.g., after a change in an operating state has already occurred) or before a change in an operating state of the complex device, which results from the respective operating states of the noise-generating components. If the current or new total value exceeds a specified limit, a warning signal can be generated or another action can be triggered. For example, an intended change in the operating state, such as a change in the speed of a conveyor belt, can be prevented.

[0031] In general, the method for determining a total value from the component values ​​can be carried out by a separate unit, which can be implemented as an external unit or integrated into the complex device, or by a control unit or evaluation unit of the complex device. Implementation can be achieved, for example, by means of a calculation unit, i.e., a combination of software and hardware.

[0032] According to a further embodiment, if a predefined limit value (which may already be lower than a limit value specified by a standard) for the total value is exceeded, an action can be triggered, in particular replacing one or more noise-generating components with noise-generating components whose component values ​​result in a total value of the complex device that is equal to or lower than the predefined limit value, or recommending or prescribing the performance of a standard-compliant metrological determination of the actual (not merely estimated) total value. The latter is particularly suitable if a metrological determination of the total value involves significantly less effort than replacing one or more components, or if no components are available that would result in a lower total value.The metrological determination may result in the total value being lower than the estimated value determined using the method. In this case, no further action is required.

[0033] As already explained above, in practice the sound power level L w as the noise emission of a component or complex device. In this case, the total sound power value can be determined by summing the component sound power values. If the sound power is specified as a sound power level, the logarithmic scale must be taken into account. The prerequisite for the admissibility of summing the power levels is the incoherence of the individual sound sources.

[0034] Especially for intermittently operated noise-generating components, it is advisable to use a time-averaged value of the sound power or sound power level (in the case of an emission measurement) or a time-averaged value of the sound pressure or sound pressure level (in the case of an immission measurement). For example, a corresponding mean value can be determined over a measurement interval of 60 seconds. This mean value will vary significantly depending on the frequency of operation of the component per unit of time.

[0035] It should be mentioned at this point that the sound power or sound pressure can of course also be subjected to a frequency weighting, for example an A-weighting or C-weighting.

[0036] If the sound pressure or the sound pressure level is to be used in an immission measurement to describe the noise generation of the components or the complex device, the position of the measuring point in relation to the noise-generating component must also be taken into account when determining a component value.

[0037] In this case, it is advisable to provide one or more component values ​​for each of the at least two noise-generating components, which describe the noise generation of the noise-generating component at different predetermined measurement locations in the vicinity of the noise-generating component. This also allows for non-isotropic radiation characteristics to be taken into account. The overall value of the complex device can then be determined at a predetermined spatial position relative to the complex device, in particular at an operator's workstation, using this one or more component values ​​and taking into account the spatial position of the noise-generating components in the complex device.The noise-generating components will generally not be isotropic (in particular, point-like) sound sources, which always generate the same sound pressure or sound pressure level at a measuring location at a certain distance from the point-like sound source, regardless of direction, but will exhibit a direction-dependent sound pressure. In this case, when determining the total value, the distance of the measuring location from the noise-generating component (or a reference point of the components, e.g., their center of mass or geometric center) must first be determined. Then, the sound pressure or sound pressure level generated by each noise-generating component at the measuring location must be calculated.

[0038] Sound pressure level can be determined. This can be done from the plurality of component values, which represent the noise generation of the noise-generating component at a predetermined measuring point in the

[0039] Describe the environment of the noise-generating component. In particular, a component value can first be determined at a measurement location in relation to the respective noise-generating component, for example by interpolation, which lies on the connecting line between the location of interest at which the sound pressure of the complex device is to be determined and the respective noise-generating component (or the respective reference point). The sound pressure at the location of interest can then be determined taking into account the distance of the location of interest from the noise-generating component (or the respective reference point) and the distance of the respective measurement location from the noise-generating component (or the respective reference point). It should be noted that the sound pressure decreases inversely proportional to the distance from the sound source (or the reference point), i.e. according to the 1 / r law.In this case, too, adding the component values ​​to a total value is only permissible if the individual sound sources are incoherent. However, this is usually the case.

[0040] A device for determining the total value according to the method described above comprises one or more storage devices in which the component values ​​of the noise-generating components or information for assigning corresponding component values ​​to the noise-generating components are stored, and an evaluation unit which is designed to access the one or more storage devices and to determine the total value of the noise generation of the complex device.

[0041] The entire device for determining the total value can be designed separately or integrated into the complex device, e.g., a control unit of the complex device. Of course, only the evaluation unit can also be integrated into the complex device.

[0042] According to one embodiment, the evaluation unit can be configured to acquire information characterizing the current or a possible (including future) operating state of the noise-generating components. This enables the evaluation unit to determine the overall value for the complex device using component values ​​for the respective operating state of the noise-generating components.

[0043] According to a further embodiment, each noise-generating component can have a memory device in which one or more component values ​​for one or more operating states of the respective noise-generating component or information for assigning one or more component values ​​for one or more operating states of the respective noise-generating component to the latter are stored, for example a serial number or a type designation.

[0044] The relevant component values ​​can be stored in a central storage device of the device for determining the total value itself or in a central external storage device to which the device for carrying out the method, in particular the evaluation unit, has access.

[0045] The complex device can, for example, be designed as an inspection machine, which preferably comprises one or more electric motor-driven conveyor belts and one or more ejector devices.

[0046] The evaluation unit of the complex device can be designed in such a way that, when determining the total value, currently set operating parameters, for example the transport speed of conveyor belts, the number, type, operating pressure or the frequency and actuation duration of ejector blow nozzles, as well as the quality of the production process at the location where the device is used, for example the current ejection rate for defective products in a production line in which the complex device is integrated, are taken into account.The quality of the production process ultimately determines the operating state of the noise-generating components, for example the ejector devices (the frequency of activation and the duration of the active state influence the noise generation if the component value is determined by averaging the physical quantity describing the noise generation), and thus the operating state and the overall value of the complex device.

[0047] This makes it possible for the first time to easily obtain an estimate for the noise generation of a complex device depending on the actual operation of the complex device at the respective location, ie depending on the determined, averaged or assumed frequency of actuation of ejectors for sorting out defective products in a real or assumed production line.

[0048] A noise-generating component, which is particularly suitable for a complex device according to the present invention, but can also be used in conjunction with other complex devices or methods, can have a memory device in which one or more component values ​​for one or more operating states of the respective noise-generating component or information for assigning one or more component values ​​for one or more operating states of the respective noise-generating component to the latter are stored, for example a serial number or a type designation. This makes it possible to read out the stored values ​​and from them to estimate the noise development of the complex device into which the noise-generating component is integrated, together with other noise-generating components.As already described above, the noise-generating component can be any device, for example a conveyor belt, an ejector comprising one or more blowing nozzles, or a pusher.

[0049] According to an embodiment of the invention, which can also be used independently of the method described above, a simplified method is used for determining one or more component values ​​of a quantity (in particular the sound power or the sound pressure) which describes the noise development of a noise-generating component, compared to the methods commonly used, as defined in standards or other regulations.

[0050] For this purpose, the component in question is positioned on a carrier plate or other base, in particular fastened in the same way or in a similar way as is done during assembly of the component in a complex device. The component positioned on the carrier plate or base is covered with a protective hood, which is preferably designed to be soundproof. This prevents ambient noise from spreading inside the protective hood. The protective hood and the base form a closed measuring chamber in which the noise-generating component is housed. The measuring chamber can be relatively small compared to the component. For example, the measuring chamber can have only twice to five times the volume of the component.The minimum distance from any point on the outer perimeter of the component to the inner wall of the cover can also be small, for example, a minimum value of 5 cm, 20 cm, or 40 cm. The cover can also have a sound-absorbing coating or sound-absorbing structures on its inner walls to prevent or at least dampen reflections.

[0051] One or more sound sensors, particularly microphones, can be installed in the measurement chamber. These serve to measure the sound pressure at the respective measurement location, i.e., at the position of the respective sound sensor. The sound sensors can be arranged and attached to the inner wall of the cover.

[0052] From the one or more measured values ​​recorded by the one or more sound sensors, one or more component values ​​are determined for the quantity describing the respective component, which would result if the measurement had been determined according to a specified specification. For example, in the simplest case, the sound pressure can be measured over a specified time interval using a single microphone provided in the measuring room, and from this an average sound pressure can be determined. Using a single correction factor (in this case a single one), an average sound power can then be determined from the thus determined average sound pressure. This average sound power would result if the sound power had been determined according to a specified specification (hereinafter referred to as the "standard value").

[0053] For example, two different methods are often used to determine sound power: measuring the sound pressure level and determining the sound intensity on an enveloping surface. The values ​​determined in this way characterize the sound emission of a sound source (e.g., a noise-generating component) regardless of the ambient conditions on site.

[0054] The DIN EN ISO 3740 series of standards (DIN EN ISO 3741, 3742, 3743, 3744, 3745, 3746, and 3747) is based on the measurement of sound pressure levels on an enveloping surface or in a diffuse sound field. This method allows the determination of the sound power levels of machines, devices, and assemblies in various environments.

[0055] The DIN EN ISO 9614 series of standards (DIN EN ISO 9614-1, 9614-2, and 9614-3) is based on the measurement of sound intensity. This method involves determining the sound power levels of machines, devices, and assemblies using a sound intensity probe. This method is also applicable in various environments.

[0056] To determine the correction factor, the component in question can be subjected to either the simplified measurement described above or one of the two complex standardized procedures described above. Once the correction factor has been determined, it can also be used to measure other—at least other similar—components.

[0057] Of course, the simplified method according to the invention can also be used to acquire measured values ​​at several different positions within the measuring space. These can then be used to determine a standard value using a suitable correction rule. This can be done, for example, by calculating an average or a total value and determining a standard value using a correction factor. Instead of a total value, a weighted total value can also be used using weighted addition (i.e., each measured value is multiplied by a predetermined weight value, and the weighted measured values ​​are added together to form a weighted total value).

[0058] The invention is explained in more detail below with reference to exemplary embodiments shown in the drawing.

[0059] Fig. 1 is a perspective view of a sorting device with several noise-generating components; and

[0060] Fig. 2 is a perspective view illustrating the principle of measuring the sound power of a noise-generating device using an enveloping surface in the form of a hemispherical surface; Fig. 3 is a perspective view illustrating the principle of measuring the sound power of a noise-generating device using an enveloping surface in the form of a cuboid surface;

[0061] Fig. 4 is a perspective view of a simple device for measuring the sound power or sound pressure of a noise-generating component; and

[0062] Fig. 5 a table with sound pressure levels (l_Ae q ; t eq =60s) for three different types of blow nozzles with different actuation times.

[0063] The sorting device 100 shown in Fig. 1 comprises two belt conveyors 102, 104, each having a conveyor belt 106, 108, which are each driven by an electric motor drive 110, 112 such that products (not shown in detail) are transported in the direction of arrow A on the respective upper runs of the conveyor belts 106, 108. Furthermore, the sorting device comprises two pushers (pushing devices), with a first pusher 114 arranged on the belt conveyor 102 and a second pusher 116 arranged on the belt conveyor 104. The pushers 114, 116 are designed as so-called short-stroke pushers, ie they each comprise an adjustment device with which a pusher head 114c, 116c of the respective pusher 114, 116 can be positioned in a starting position in the direction transverse to the conveying direction of the respective belt conveyor 102, 104.This starting position can be selected depending on the size and / or position of the products transported on the conveyor belts 106, 108. For this purpose, each of the short-stroke pushers 114, 116 has two supports 114a, 114b and 116a, 116b, respectively, by means of which the respective pusher head 114c, 116c is displaceably guided relative to a stationary base body 114d, 116d and can be locked in the selected starting position. In Fig. 1, the short-stroke pusher 114 is shown in a maximally retracted starting position and the short-stroke pusher 116 in a maximally advanced starting position. This merely serves to visualize the maximum possible adjustment range available for setting the starting position. The actual pusher movement also occurs transversely to the transport direction A of the belt conveyors 102, 104 in the direction of the arrows B in Fig. 1.For this purpose, each of the pushers 114, 116 comprises a pusher plate 114e, 116e, which is enclosed by the respective pusher head 114c, 116c. Each pusher plate 114e, 116e can be moved in the direction of the arrow by a predetermined maximum distance in the direction of arrows B in Fig. 1 by means of a drive (not shown) provided in the pusher head 114c, 116c, which can be designed, for example, as a piston-cylinder unit. This movement occurs so quickly that a product located in front of the respective pusher plate 114e, 116e at the relevant moment is pushed in the direction B by the respective conveyor belt 106, 108.

[0064] The short-stroke pushers 114, 116 shown in Fig. 1 have the special feature that the supports 114a and 116a are each simultaneously designed as two blow nozzles 118. These blow nozzles 118 can be pressurized with compressed air to generate an air flow that is also directed in direction B. This also allows products that are conveyed on the respective conveyor belt 106, 108 in the direction of arrow A to be blown by the respective belt conveyor 102, 104. These blow nozzles 118 can also be controlled to generate a continuous air flow, which serves to remove all products that are conveyed from the respective belt conveyor during a total time in which the continuous air flow is maintained (clearing at the start of production).

[0065] Thus, the sorting device shown in Fig. 1 has a whole series of noise sources. The electric motor drives 110, 112 and the conveyor belts 106, 108 of the belt conveyors 102, 104 generate noise that is primarily determined by the drive speed of the drives 110, 112 and the rotational speed of the conveyor belts 106, 108, respectively. The rotational speed of the conveyor belts 106, 108 influences the noise generated by the corresponding deflection rollers 102a, 104a and the rotational edges 102b, 104b (knife edge), over which the respective conveyor belt is dragged. Further sources of noise are the blowing nozzles 118 and the movement of the pusher plates 114e, 116e or the respective drives in the respective pusher head 114c, 116c. Of course, the pushing of the products down from the conveyor belts 106, 108 also generates noise.In this case, a baffle plate (not shown) can also be provided next to the respective belt conveyor 102, 104, so that the products pushed or blown by the respective conveyor belt 106, 108 impact the respective baffle plate and subsequently fall into a container (not shown). This, of course, also generates noise.

[0066] As already explained above, there is often a requirement to determine the total noise generated by such a complex device, at least when the complex device is fully manufactured or is being put into operation. For this purpose, manufacturers are regularly required to specify the sound power or sound power level for such complex devices. However, measuring the sound power of a large, complex device is correspondingly complex.

[0067] As already explained above, it may also be necessary to specify sound pressure instead of or in addition to sound power. In this case, however, it is necessary to define the position in relation to the noise-generating device at which the sound pressure is to be specified.

[0068] It should be noted at this point that the terms ‘sound power’ and ‘sound pressure’ are used below regardless of whether the values ​​in question are given as level values ​​(‘sound power level’ or ‘sound level’ or ‘sound pressure level’), i.e. on a logarithmic scale.

[0069] If, during a measurement of the respective sound quantity in the case of a complex device that has already been manufactured or possibly even already been installed at a customer's site, it turns out that specified limit values ​​have been exceeded, the effort required to modify the device so that the limit values ​​are complied with is usually very great, if not impossible.

[0070] Furthermore, in complex devices with a plurality of noise-generating components, the noise generation often depends on the operating state of the complex device. The operating state of the complex device is determined by the operating states of the individual noise-generating components, or vice versa, i.e., the operating states of the individual noise-generating components determine the operating state of the complex device. For example, the operating state of the complex device in the form of the sorting device 100 according to Fig. 1 depends on whether and in which operating state one or both of the short-stroke pushers 114, 116 are active. The purely mechanical movement of the pusher plate 114e, 116e will cause less noise than the blow nozzles 118.

[0071] Often, the value of the physical quantity chosen to describe noise generation (especially sound power and sound pressure) is not only subjected to a frequency weighting or determined with a corresponding load, but also given as a time average. For this purpose, a measurement is taken over a specified time interval, for example, 60 seconds. The respective quantity is integrated over this time interval and then divided by the length of the time interval.

[0072] To evaluate the noise development of intermittently operated noise-generating devices, for example a pusher, the sound level (= sound power level) L averaged over a time interval of 60 seconds can be used. eq If this sound power level is determined with the frequency weighting A, the symbol LA is often used. eq used.

[0073] In an inspection device comprising a sorting device according to Fig. 1, the frequency of activation of the ejector devices, i.e., the pushers or blow nozzles, will depend on the rate of products identified as defective by the inspection device and subsequently removed from the product stream by the inspection device by appropriately controlling the sorting device. Generally speaking, the operating state of a complex device can also depend on the product quality or other parameters that influence the operating state of the complex device during its operation. Of course, the complex device can also be part of an entire production line.

[0074] Conversely, the operating state can be controlled automatically or through operator intervention depending on the noise level. If the method for estimating the noise level of a complex device detects during operation that the noise level exceeds a predetermined limit, a signal, such as an operator call signal, can be generated accordingly, or the operating state of the complex device or even of an entire production line can be changed so that the limit is maintained. For example, the production speed can be reduced. At a lower production speed, various noise-generating components, such as motor drives, conveyor belts, and the like, will generate less noise.

[0075] The invention thus also provides, as described below, the possibility of estimating the noise development at any time during the conception, construction, provision of the components for the realization of the complex device or assembly of the device as well as during the operation of the complex device.

[0076] Instead of measuring the noise generation of a fully manufactured device or a complex device installed for operation at a customer's site, the invention starts at an earlier point in time. If specific noise-generating components are required for a complex device, the noise generation is determined in advance for each specific component or even for each component type. This can be done using conventional measurement methods. The physical quantity used to describe the noise generation can also be selected in a conventional manner.

[0077] Depending on this, the noise generation of the complex device is estimated by superimposing the noise generation of the individual components. When using sound power as a physical parameter to describe noise generation, this can be achieved by simply adding the individual sound power levels of the relevant noise-generating components. This neglects the fact that the noise-generating components may behave differently in terms of noise generation after being installed in or assembled into a complex device than when measured as individual components. In particular, the absorption of sound power by other components is naturally neglected.

[0078] If the sound power is specified as a sound power level, it must of course be taken into account that the sound power values ​​cannot be simply added together. Rather, the level values ​​must ultimately be delogarithmized for the addition. The addition of n level values ​​is carried out according to the equation where the individual level values ​​are denoted by Lj.

[0079] If sound pressure is used as a physical quantity to describe noise generation instead of sound power, it is necessary to specify at which position in relation to the complex device the sound pressure is to be determined.

[0080] In a simple case, the sound pressure for the individual noise-generating components can then be determined at a specific distance, for example, at a distance of 1 m. Furthermore, in such a case, it can be approximately assumed that the sound pressure has a constant value at this distance, regardless of direction. The distance can be determined from a specific point within the noise-generating component. To determine such a sound pressure value, the sound pressure can of course also be measured at several different positions at a distance of 1 m, and an average value can then be calculated from these values, which is then used for the further process.

[0081] The individual sound pressure values ​​of the noise-generating components determined in this way can then be used to estimate the sound pressure of the complex device at a specific position in relation to the complex device. For example, the distance of each component (starting from the point used to determine the sound pressure of the respective component) from the position at which the sound pressure for the complex device is to be determined or estimated can be determined. The sound pressure generated at this distance from the noise-generating component in question can then be calculated from the value previously determined for the respective component by taking the changed distance into account. In this case, it can be used to take into account the fact that sound pressure is inversely proportional to distance. For example, doubling the distance results in half the sound pressure value.

[0082] It would also be conceivable to measure the sound pressure directionally for each noise-generating component or each type of noise-generating component and to take this directionality into account when determining the sound pressure for the complex device.

[0083] In the sorting device 100 according to Fig. 1, the value for the physical quantity describing the noise generation of the individual components can thus already be taken into account during the development of the sorting device 100. This is because the individual noise-generating components, in particular the belt conveyors 102, 104 (with the respective electric motor drives 110, 112, the deflection rollers 102a, 104a, the peripheral edge 102b, 104b designed as a knife edge), the pushers 114, 116, and the blow nozzles 118, are in many cases standard components that can be used in the development of complex devices.

[0084] Thus, the noise development for each such specific noise-generating component can be determined in advance. As already mentioned above, the noise development can also be determined for a specific component type, using a predetermined number of identical components and averaging the values ​​determined for these components.

[0085] It is also possible to determine these values ​​for a variety of different noise-generating components and store them in a database or in a memory provided for the respective noise-generating component. This allows corresponding values ​​for the noise generation to be determined and stored for a variety of different noise-generating components, for example, for a variety of belt conveyors with different belt lengths, belt widths, belt thicknesses, belt materials, or the like.

[0086] The noise development can also be determined for different operating states of the relevant noise-generating components, for example for different drive speeds of the belt conveyors 102, 104, for different operating pressures of the blowing nozzles 118, for different frequencies of activation of the blowing nozzles within a predetermined time period, for example within 60 seconds, and / or for different activation durations of the blowing nozzles (instead, the total activation time of the blowing nozzle within a predetermined time period can also be used).

[0087] In this way, the noise generation of a complex device can be estimated during the design or construction phase. If, for example, a designer determines that the fully designed complex device exceeds a specified limit when applying the noise estimation method, appropriate measures can be taken. For example, one or more noise-generating components can be replaced with other components for which a lower value (component value) for the relevant physical quantity describing the noise generation has been determined or stored. As already mentioned, this can be an identical or similar (fulfilling the same technical purpose) but quieter example of the same component type, or an example of a different component type.For example, a different type of blowing nozzle can be used which also fulfills the required functionality but is less noisy.

[0088] According to a first alternative, the limit value can be selected in such a way that if it is exceeded, there is a high probability (for example, greater than 80%, 90%, 95% or 99%) that a permissible (not necessarily the same) limit value will be exceeded even if the noise emission of the complex device is measured correctly (in accordance with the standards).

[0089] According to a second alternative, the limit value can be set such that, if it is undershot, it is ensured with a very high probability (for example, greater than 80%, 90%, 95%, or 99%) that even with a correct measurement of the noise generation of the complex device, a permissible (not necessarily the same) limit value will not be undershot or exceeded. In this case, a further, higher limit value can also be set, selected in accordance with the first alternative above. If the method produces a value that is greater than the lower limit value and less than (or equal to) the higher limit value, this can be interpreted as meaning that there is a sufficient probability that the noise generation of the complex device could still be acceptable if a correct measurement is carried out.

[0090] The implementation of a correct (i.e., standard-compliant) measurement of sound power is briefly explained below with reference to Figs. 2 and 3. The figures show two different methods, which can be selected as needed. Since the implementation of a correct measurement of a physical quantity for describing the noise generation of a device, in particular sound power and sound pressure, does not represent an isolated core of the present invention, it will only be briefly discussed below.

[0091] As already explained above, the sound power or the sound power level is a measure of the total sound power emitted by a sound source. To measure the sound power, an envelope is used which is spanned around the sound source. A reflecting surface R is assumed to be below the sound source. This is shown hatched in Fig. 3. The (imaginary) envelope in the measuring method according to Fig. 2 is hemispherical. A predetermined number of measuring points are defined on this hemisphere. In the variant shown in Fig. 2, three measuring points M1, M2 and M3 were defined which are positioned on the envelope surface H1. The hemispherical envelope surface H1 has a predetermined radius which must be chosen large enough to ensure that the measurement is taken in the far field of the sound source V. The center orthe center of the hemispherical envelope H1 is the origin of the Cartesian coordinate system shown in Fig. 2 with the axes x, y, z.

[0092] From the measured values ​​at the measuring points M1, M2, M3, taking into account the size of the envelope H1, the total sound power emitted by the envelope H1 can be determined.

[0093] Since the measurement is carried out using microphones as sensors that record the sound pressure, the following procedure can be used to determine the sound power:

[0094] First, it is assumed that the device to be measured can be measured under free-field conditions, ie the sound can propagate unhindered and there is no significant external noise influence.

[0095] In this case, the sound power level Lw can be calculated from the average sound pressure level L pon a measuring surface enclosing the machine and the measuring surface area S (of the microphone) according to the following formula: L w = L p + 10 ■ log

[0096] The summand Ls is also referred to as the measuring area measure.

[0097] Another variant for determining the sound power or sound power level is shown in Fig. 3. Here, a cuboid reference surface H2 is used, on which a total of five measuring points M1 to M5 are provided, each centrally located on each of the cuboid measuring surfaces (except for the reflecting floor surface). The distance of the measuring points from the respective surface of the sound source represented as the reference cuboid can be chosen to be constant, for example, 1 m.

[0098] A disadvantage of these methods, however, is their relatively high space requirements. Although the method according to the invention already reduces the space requirements because the entire complex device as a sound source no longer needs to be measured, but only the individual noise-generating components, the measurement methods used previously still require a relatively high amount of space.

[0099] To further reduce the space requirement and to facilitate the implementation of the method, the following method is proposed, which will now be explained with reference to Fig. 4.

[0100] Fig. 4 shows a measuring device 200 for simplified sound power measurement. The measuring device 200 comprises a base body 202, on which a support device 204 is provided, which serves to fix the respective test object. A belt conveyor 206 is shown as the test object in Fig. 4. On the surface or upper side 202a of the base body 202, six measuring positions M1 to M6 are provided, each of which has a measuring microphone 208 arranged thereon. The measuring device 200 further comprises a cover 210, the inner wall of which, together with the upper side 202a of the base body 202, defines a measuring space for the test object, in the illustrated case the belt conveyor 206. The cover 210 and the base body 202 are preferably designed to provide the greatest possible sound insulation.

[0101] The measuring device 200 can further be configured such that an evaluation unit (not shown in detail) is accommodated in the base body 202. Of course, the evaluation unit can also be located outside the base body. In any case, the signals from the measuring microphones 208 are fed to the evaluation unit. The evaluation unit uses the measurement signals to determine the desired value, for example the sound power level. Since the measuring microphones 208 record the sound pressure at the respective measurement location, the evaluation unit is configured such that it determines a value for the sound power or the sound power level using the relevant sound pressure values ​​at the measurement positions. To do this, the evaluation unit can, for example, determine the average sound pressure and, from this, for example, using a suitable correction factor, the sound power.Instead of a simple correction factor (which can also be dependent on the mean value of the measured power), any correction quantity or correction function can be used. The goal of the correction is to approximate the sound power determined in this way as closely as possible to the sound power determined using conventional measurement methods (see the above comments on Figs. 2 and 3).

[0102] The measuring device 200 according to Fig. 4 can also perform additional measuring functions. For example, the device can be designed as a measuring station for detecting vibrations. For this purpose, sensors (not shown) for detecting vibrations (for example, acceleration sensors) can be provided in the base body 202 or in an upper plate (not shown in detail) of the base body 202, or also in the support device 204. The test object, for example in the form of the belt conveyor 206 shown, can thus perform multiple measurements to determine the physical properties of the test object.

[0103] The table shown in Fig. 5 shows the sound pressure levels LA measured with this measuring device for three different blowing nozzles eq, i.e., the A-frequency-weighted sound pressure level, averaged over a time interval of 60 seconds. The nozzles differ in their geometry, particularly in their length and diameter, through which the air stream is discharged. The sound pressure level was determined for a specified total duration of the compressed air bursts (this can be realized by a single compressed air burst or by multiple compressed air bursts) during the measurement interval of 60 seconds.

[0104] In a sorting device as described above with reference to Fig. 1, such different total durations of the compressed air bursts can result from different ejection rates. This example impressively illustrates the range within which the sound power or sound power level can vary when the operating state of a sound-generating component—in this case, the operating state of a blowing nozzle—changes, whereby the change in the operating state depends on the control of the respective component or also the control (and thus the operating state) of the complex device comprising the respective sound-generating component. These measurement results show that the measuring device 200 delivers at least internally consistent results. If, for example, the total duration of the compressed air bursts is doubled, an expected increase in the sound power level of approximately 3 dB is also measured.If the time period is increased by a factor of 100, the sound power level increases by approximately 20 dB.

[0105] The values ​​presented in the table in Fig. 5 are classified into three groups: a first group with values ​​greater than 80 dB, which already exceeds a frequently used limit (of 80 dB); a second group with values ​​between 70 dB and 80 dB; and a third group with values ​​less than 70 dB. The first group always exceeds the limit of 80 dB, even if the blowing nozzle in question were installed as the only noise-generating component in a complex device and operated with corresponding total durations for the compressed air bursts.In the second group, a standardized re-measurement is indicated if the blowing nozzle in question is the only component included in a complex device, and in the third group, it can be assumed with a high degree of certainty that a standardized re-measurement is not required if it is the only noise-generating component in a complex device. If several noise-generating components are included in a complex device, a total value can first be determined using the method according to the invention (if necessary for the relevant possible operating modes) and checked to see whether this total value is fundamentally acceptable (Group 3), requires a standardized re-measurement (Group 2), or would in any case lead to an exceedance and must therefore be avoided if possible, because in such a case every operator must take noise protection measures, such as wearing ear protection (Group 1).

[0106] This demonstrates that this simplified measurement method or setup is sufficient to carry out the method described above for estimating the noise generation of a complex device with sufficiently accurate results. However, as already described above, the system described above can also be applied if a known measurement method is used instead of the simplified measurement method.

[0107] As already mentioned above, the method according to the invention can be carried out both during the design, construction, and assembly phases, as well as during the operation of a complex device, even integrated into an entire production line. This can be done either by an operator using the necessary data for the individual noise-generating components and information about their operating states, or automatically, using a suitable evaluation device that has access to the relevant data and information.

[0108] This is illustrated schematically in Fig. 1. Information about the operating state of the device, in particular about its speed, is supplied to an evaluation device 120 from the motor drives 110 and 112 of the belt conveyors 102 and 104. Furthermore, values ​​for the relevant physical quantity describing the noise generation of the relevant component can be stored in the motor drives or in storage units not shown in detail, naturally also depending on possible operating states. Furthermore, corresponding data and information can also be supplied to the evaluation unit 120 from the pushers 114, 116.The evaluation unit 20 can then estimate the noise development of the entire complex device by calculating a corresponding total value from these data, which describe the noise generation of the relevant noise-generating component (depending on the respective operating state).

[0109] The evaluation device 120 can of course also transmit this total value to a higher-level data processing unit or display it by means of a display unit (continuously or on request).

[0110] The evaluation unit 120 can also be configured such that, before changing the operating state of the complex device 100 (which is defined by the individual operating states of the respective noise-generating components), it checks whether the operating state resulting from the change leads to noise generation that exceeds a predetermined limit. For this purpose, the evaluation unit 120 determines the expected total value of the relevant physical quantity, for example, the expected sound power level. If the predetermined limit is exceeded by the total value thus determined, a signal, for example, an operator call signal, can be generated, or the change in the operating state can be blocked.

[0111] Finally, it should be noted that the method according to the invention can be applied to any complex device, regardless of its design and the type and design of the noise-generating components it contains. This applies in particular to stationary tools and production machines, e.g., those located in a production hall.

[0112] List of reference symbols

[0113] 100 sorting device

[0114] 102 belt conveyors

[0115] 102a pulley

[0116] 104 belt conveyors

[0117] 104a pulley

[0118] 106 Conveyor belt

[0119] 108 Conveyor belt

[0120] 110 electric motor drive

[0121] 112 electric motor drive

[0122] 114 Pushers

[0123] 114a carrier

[0124] 114b carrier

[0125] 114c pusher head

[0126] 114d base body

[0127] 114e pusher plate

[0128] 116 pushers

[0129] 116a carrier

[0130] 116a carrier

[0131] 116b carrier

[0132] 116c pusher head

[0133] 116d base body

[0134] 116e pusher plate

[0135] 118 Blow nozzle

[0136] 120 Evaluation device

[0137] 200 measuring device

[0138] 202 basic body

[0139] 202a Top of the base body 202

[0140] 204 Carrier device

[0141] 206 belt conveyors

[0142] 208 measuring microphone

[0143] 210 Cover A Arrow direction

[0144] H1 Envelope

[0145] H2 envelope

[0146] Mi measuring point (1 <i<n; n ist ganze natürliche Zahl)

[0147] R reflecting (ground) surface

[0148] V Sound source

Claims

Patent claims 1. Method for estimating the noise development of a complex device, in particular an inspection machine, which has at least two noise-generating components (104, 106, 108, 114, 116, 118), (a) wherein a total value of a physical quantity is determined which describes the noise development of the complex device (100), in particular a total value for the sound power and / or the sound pressure, characterized in that (b) that for each of the at least two noise-generating components (104, 106, 108, 114, 116, 118), at least one component value of the physical quantity is provided, which describes the noise development of the respective noise-generating component (104, 106, 108, 114, 116, 118), and (c) that the total value for the complex device (100) is determined from component values ​​for the at least two noise-generating components (104, 106, 108, 114, 116, 118).

2. Method according to claim 1, characterized in that the at least one component value for the respective noise-generating component (104, 106, 108, 114, 116, 118) is determined by metrological determination of a measured component value for the relevant noise-generating component (104, 106, 108, 114, 116, 118) or by determining a type component value for the relevant type of noise-generating component (104, 106, 108, 114, 116, 118), in particular by determining an average value for a predetermined number of identical or comparable noise-generating components (104, 106, 108, 114, 116, 118).

3. Method according to claim 1 or 2, characterized in that the component values ​​are provided in a database, each assigned or assignable to the respective component (104, 106, 108, 114, 116, 118).

4. Method according to claim 1 or 2, characterized in that the at least one component value is stored in the relevant component (104, 106, 108, 114, 116, 118) and is provided in a readable or readable manner, preferably machine-readable, on or in the component (104, 106, 108, 114, 116, 118).

5. Method according to one of the preceding claims, characterized in that a noise-generating component (104, 106, 108, 114, 116, 118) has one or more operating states, wherein at least one component value is assigned to each operating state or selected operating states or at least one component value of an operating state is determined from one or more component values ​​of further operating states.

6. Method according to one of the preceding claims, characterized in that the complex device (100) has one or more operating states and that each of these operating states is assigned a total value and that each operating state of the complex device (100) is assigned at least one operating state of each of the noise-generating components (104, 106, 108, 114, 116, 118), wherein for each operating state of the complex device (100) a total value is determined or can be determined from the component values ​​for the respectively assigned operating states of the noise-generating components (104, 106, 108, 114, 116, 118).

7. Method according to claim 6, characterized in that the maximum total value, seen over all operating states, is determined and used to describe the noise development of the complex device (100).

8. Method according to one of claims 6 or 7, characterized in that it is applied during the operation of the complex device (100), wherein the total value is determined for a current operating state or for a planned changed operating state and wherein an action is triggered, in particular a signal is generated, when the determined total value exceeds a predetermined limit value.

9. Method according to one of the preceding claims, characterized in that when a predetermined limit value for the total value is exceeded, an action is triggered, in particular generating a warning signal or replacing one or more noise-generating components (104, 106, 108, 114, 116, 118) with noise-generating components (104, 106, 108, 114, 116, 118) whose component values ​​lead to a total value of the complex device (100) which is equal to or lower than the predetermined limit value, or recommending or prescribing the implementation of a metrological determination of the total value.

10. Method according to one of the preceding claims, characterized in that it is applied at predetermined times or after reaching predetermined phases in the course of the conception, the construction, the provision of the components for the realization of the complex device (100) or the assembly of the complex device (100). 11 . Method according to one of the preceding claims, characterized in that for the at least two noise-generating components (104, 106, 108, 114, 116, 118) one or more component values ​​are provided, which describe the noise development of the noise-generating component (104, 106, 108, 114, 116, 118) at different predetermined measuring locations in the environment of the noise-generating component (104, 106, 108, 114, 116, 118), and in that the total value of the complex device (100) at a predetermined spatial position in relation to the complex device, in particular at a workstation of an operator, using these one or more component values ​​and taking into account the spatial Position of the noise-generating components in the complex device (100) is determined.

12. Device for determining the total value according to the method according to one of the preceding claims, with one or more storage devices in which the component values ​​of the noise-generating components (104, 106, 108, 114, 116, 118) or information for assigning corresponding component values ​​to the noise-generating components (104, 106, 108, 114, 116, 118) are stored, and with an evaluation unit, preferably provided in the complex device (100), which is designed to access the one or more storage devices and to determine the total value of the noise development of the complex device (100) according to one of the preceding claims.

13. Device according to claim 12, characterized in that the evaluation unit is designed to acquire information which characterizes the current or a possible operating state of the noise-generating components (104, 106, 108, 114, 116, 118), and in that the evaluation unit determines the overall value for the complex device (100) using component values ​​for the respective operating state of the noise-generating components (104, 106, 108, 114, 116, 118).

14. Device according to one of claims 12 or 13, characterized in that one or more noise-generating components (104, 106, 108, 114, 116, 118) have a memory device in which one or more component values ​​for one or more operating states of the relevant noise-generating component (104, 106, 108, 114, 116, 118) or information for assigning one or more component values ​​for one or more operating states of the relevant noise-generating component (104, 106, 108, 114, 116, 118) to the latter are stored, for example a serial number or a type designation.

15. Device according to one of claims 12 to 14, characterized in that a central storage device is provided in which measurement component values ​​or type component values ​​for one or more operating states for the noise-generating components (104, 106, 108, 114, 116, 118) are stored.

16. Complex device, in particular an inspection machine, with a device according to one of claims 12 to 15.

17. Complex device according to claim 16, characterized in that the evaluation unit (120) takes into account one or more currently set operating parameters, for example the transport speed of conveyor belts, number, type, operating pressure or actuation duration of ejector blow nozzles, as well as the quality of the production process at the location of use of the device, for example the current ejection rate for defective products, or combinations of these operating parameters and / or parameters describing the quality, when determining the overall value.

18. Noise-generating component, in particular for a complex device according to one of claims 16 or 17, characterized in that the noise-generating component has a storage device in which one or more component values ​​for one or more operating states of the relevant noise-generating component (104, 106, 108, 114, 116, 118) or information for assigning one or more component values ​​for one or more operating states of the relevant noise-generating component (104, 106, 108, 114, 116, 118) to the latter are stored, for example a serial number or a type designation, wherein the one or more component values ​​are values ​​for a physical quantity, in particular for the sound power and / or the sound pressure, which describe the noise development of the noise-generating component.

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