Dosing device with a pressure monitoring unit and method for operating a dosing device with a pressure monitoring unit

Abstract

The invention is based on a dosing device for dosing liquid and / or pasty products, in particular foodstuffs, with at least one dosing unit (12) comprising at least one dosing pump (14) having at least one suction side (16) and at least one pressure side (18), and with at least one pressure monitoring unit (20) for detecting at least one pressure parameter.It is proposed that the pressure monitoring unit (20) is arranged along a conveying direction (22) of the dosing pump (14), in particular completely, on the suction side (16) of the dosing pump (14).

Description

Prior ArtThe invention relates to a dosing device for dosing liquid and / or pasty products, in particular foods, having at least one dosing unit which comprises at least one dosing pump which has at least one suction side and at least one pressure side, and having at least one pressure monitoring unit for detecting at least one pressure characteristic variable.The product diversity is very high, particularly in the food sector, and many different products are processed by means of the same filling line, sometimes also in very different filling quantities. The products also vary from batch to batch (partly depending on the season) and frequently also within a batch. This may result in changes in product properties that may contribute to pressure fluctuations within the filling process, which may negatively affect filling and longevity of the filling line.The products and sealing systems react in part sensitively to pressure changes, which is manifested in the case of seals and associated counter-running surfaces in metering devices by high wear. In the case of products which are to be filled by means of the metering devices, pressure changes can also lead to damage to the product to be filled or to inaccurate filling amounts.For example, DE 10 2005 044 796 A1 discloses a metering device having at least one metering unit for metering liquid and / or pasty products, in particular adhesives or sealants, which comprises at least one metering pump, and having at least one pressure monitoring unit, wherein the pressure monitoring unit is arranged along a conveying direction of the metering pump at least partially on a suction side and partially on a pressure side of the metering pump, specifically in that the pressure monitoring unit comprises a pressure sensor arranged in the region of a product inlet of the metering pump and a further pressure sensor arranged in the region of a product outlet of the metering pump. By arranging the pressure sensors at a product inlet and at a product outlet of the metering pump, it is only possible to reliably detect a pressure fluctuation occurring within the metering pump. A detection of pressure fluctuations upstream of the metering pump, which can be caused, for example, by a change in a product property of a product to be metered and which can be used to determine a pressure difference before the product enters the metering pump, is not provided in the known metering device or cannot be carried out reliably. In addition, the metering device known from DE 10 2005 044 796 A1 is not provided for use in the food industry.The object of the invention is in particular to provide a generic metering device and a generic method for operating a metering device with improved properties with regard to process safety and monitoring to minimize wear and thus reduce maintenance effort. The object is achieved according to the invention by the features of claims 1 and 8, while advantageous embodiments and developments of the invention can be gathered from the dependent claims.Disclosure of the InventionThe invention is based on a dosing device for dosing liquid and / or pasty products, in particular foods, having at least one dosing unit which comprises at least one dosing pump which has at least one suction side and at least one pressure side, and having at least one pressure monitoring unit for detecting at least one pressure characteristic variable.It is proposed that the pressure monitoring unit is arranged along a conveying direction of the metering pump, in particular completely, on the suction side of the metering pump. The embodiment of the dosing device according to the invention advantageously allows reliable dosing of liquid and / or pasty products. In particular, automated monitoring of a change in product properties of products to be dosed can be achieved. Furthermore, a parameter set counteracting the change in the product property of the product to be metered can advantageously be selected for controlling the metering pump, in particular automatically, or at least one warning can be output to an operator that another parameter set should be selected for controlling the metering pump. This advantageously makes it possible to counteract wear of the metering unit. Damage to the product to be metered can be advantageously counteracted by a delivery pressure that is too high, for example. An advantageous monitoring of a dose setting of the dosing unit can be made possible. Furthermore, an advantageous inline process control on the metering device can be made possible. Advantageously, an incorrect selection or incorrect setting of a parameter set for controlling the metering pump, which is carried out manually by an operator, can be detected at an early stage in order to be able to avoid damage resulting therefrom. It is advantageously possible to realize a metering device which has a low maintenance outlay and which can advantageously counteract high loads which contribute to wear.The metering device serves in particular for metering liquid and / or pasty products, wherein the metering device is provided in particular for dispensing the product in a defined quantity, in particular into a sales container provided for this purpose. The dosing device can in particular comprise one or more dosing units. The at least one metering unit is formed in particular by a cannon. The dosing unit serves in particular for the direct application of the product into a container provided for this purpose. The metering unit preferably comprises at least the metering pump for conveying the liquid and / or pasty products. The metering unit can also have a multiplicity of metering pumps which are preferably provided individually for conveying the liquid and / or pasty products. "Provided" is to be understood in particular as meaning specially configured, specially programmed, specially designed and / or specially equipped. The fact that an object is provided for a specific function is to be understood in particular to mean that the object fulfills and / or executes this specific function in at least one application state and / or operating state. The dosing unit preferably has at least one changeover valve for switching between suction and ejection. By means of the changeover valve, in particular a pumping direction of the metering pump can be changed. Suction can serve, for example, for temporarily stopping dispensing, for example, in the event of a container change. Furthermore, a dripping can be avoided as a result, for example. The metering pump and / or the changeover valve is / are in particular servo-controlled. Alternatively, drives without servo drives that supply a constant force, such as pneumatic drives or the like, would also be conceivable. Alternatively or additionally, the evaluation of data from an entire production and, derived therefrom, the finding of optimum parameters for a recipe would also be conceivable. For example, a parameter can be continuously adapted depending on environmental and / or process conditions.The metering pump / s is / are preferably connected to a tank unit of the metering device via an, in particular individual, feed line of the metering device. The tank unit comprises in particular at least one tank element in which the liquid / n or pasty / n product / s can be arranged. It is also conceivable for the tank unit to comprise a plurality of tank elements, wherein different products can be arranged in the individual tank elements, which products can be conveyed into containers by means of the metering pump / s, in order in particular to enable a so-called sorted filling (ABAB or ABCD). Alternatively or additionally, a plurality of tank elements and / or a series connection of a plurality of metering devices is also conceivable for multilayer products or products with different components, in order to produce, for example, a puddle with a cream hood, which is filled in a cup, or the like. It is conceivable that each metering pump is assigned a single tank element of the tank unit, that each metering pump is assigned a plurality of tank elements, or that all metering pumps are assigned a single tank element. Further configurations, distributions and / or fluidic connections of the tank unit and of the metering unit, which appear expedient to a person skilled in the art, are likewise conceivable. Preferably, a product to be metered is filled by means of the metering pump from the tank element into a sales container in a manner already known to a person skilled in the art. A conveying direction of the metering pump, along which the product can be conveyed by means of the metering pump, preferably extends, starting from the tank element, via the feed line in the direction of the metering pump as far as the suction side, in particular as far as a product inlet of the metering pump, and further from the suction side to the pressure side, in particular as far as a metering nozzle of the metering unit or as far as a product outlet of the metering pump, via which the product can be filled into a sales container, in particular a cup.Preferably, the pressure monitoring unit is arranged along the conveying direction of the metering pump in its entirety on the suction side of the metering pump. The pressure monitoring unit is preferably arranged in its entirety upstream of the metering unit along the conveying direction of the metering pump. Preferably, in particular all, components and / or assemblies of the pressure monitoring unit are arranged along the conveying direction of the metering pump on the suction side of the metering pump. The pressure side of the metering pump is preferably free of components and / or assemblies of the pressure monitoring unit along the conveying direction of the metering pump. Preferably, no components and / or assemblies of the pressure monitoring unit are arranged after the dosing unit. Preferably, a region of the metering pump between the suction side and the pressure side is free of components and / or assemblies of the pressure monitoring unit. Preferably, in particular all, pressure sensors of the pressure monitoring unit are arranged along the conveying direction of the metering pump, in or on fluidic lines and / or receiving containers of the metering device, which are connected to the metering pump in fluidic terms on the suction side of the metering pump. Preferably, in particular all, pressure sensors of the pressure monitoring unit are arranged upstream of the metering unit along the conveying direction of the metering pump. The pressure characteristic variable / s, which can / are detected by means of the pressure monitoring unit, is / are preferably an, in particular maximum, differential pressure and / or a static pressure of the product to be metered in at least one line and / or in at least one receiving container of the metering unit, in particular in a region upstream of the metering pump. The pressure monitoring unit is preferably provided for detecting an, in particular maximum, differential pressure and / or a static pressure of the product to be metered upstream of the metering unit, in particular upstream of the metering pump. The pressure monitoring unit is preferably provided for detecting the pressure characteristic variable / s, in particular exclusively, before the product to be metered enters the metering pump. The pressure characteristic / s can / can be detected by means of the pressure monitoring unit at different times and / or at different positions in the line and / or in the receiving container before entry of the product to be metered into the metering pump. It is advantageously possible to infer a change in product properties of the product to be dosed, in particular since the pressure characteristic / s of the product to be dosed changes, for example, by a friction between the moving product and contact surfaces of the line and / or of the receiving container, wherein this friction can be influenced, for example, by a flow speed of the product to be dosed, by the density of the product to be dosed, by piece components present in the product to be dosed, such as lumps, fruit pieces or the like, and / or further factors. In particular in the area of seals, it is expedient to have a low overpressure in order to advantageously realize a secure pressing of the seals against corresponding counter surfaces.It is furthermore proposed that the pressure monitoring unit has at least one pressure sensor which is arranged in the vicinity of a product inlet of the metering pump arranged on the suction side of the metering pump, and at least one further pressure sensor which is arranged upstream of the pressure sensor along a conveying direction of the metering pump. A "close range" is preferably to be understood as a range which has a maximum extent of in particular less than 500 mm, preferably of less than 250 mm and particularly preferably of less than 100 mm. The pressure sensor preferably has a maximum distance relative to the product inlet of the metering pump, which is in particular less than 300 mm, preferably less than 150 mm and particularly preferably less than 75 mm. Most preferably, the pressure sensor is arranged directly at the product inlet of the metering pump. The pressure sensor is preferably arranged spaced apart along the conveying direction of the metering pump relative to the further pressure sensor. In particular, the pressure sensor is arranged along the conveying direction of the metering pump downstream of the further pressure sensor. The pressure sensor preferably has a maximum distance relative to the further pressure sensor, which is in particular less than 3,000 mm, preferably less than 2,000 mm and particularly preferably less than 750 mm. The pressure sensor and the further pressure sensor can have an identical design or can have different designs. The pressure sensor and / or the further pressure sensor can be designed as a piezoresistive pressure sensor, as a piezoelectric pressure sensor, as a capacitive pressure sensor or as another pressure sensor that appears expedient to a person skilled in the art. The pressure sensor and the further pressure sensor are preferably designed as so-called pressure measurement transducers (also known as pressure measurement transducers or pressure transmitters), which are connected via an analog or digital output to a computing unit of the dosing device in a transmission-related manner. The configuration according to the invention advantageously allows automated monitoring of a change in product properties of products to be metered. Advantageously, a monitoring of a change in product properties, which could lead to a high closure of the metering pump and / or which could lead to an impairment of a filling of the product to be metered, can be reliably detected. Furthermore, a parameter set counteracting the change in the product property of the product to be metered can advantageously be selected for controlling the metering pump, in particular automatically, or at least one warning can be output to an operator that another parameter set should be selected for controlling the metering pump. This advantageously makes it possible to counteract wear of the metering unit. Damage to the product to be metered can be advantageously counteracted by a delivery pressure that is too high, for example. Furthermore, an advantageous inline process control on the metering device can be made possible.It is furthermore proposed that the metering device comprises at least one, in particular the already aforementioned, tank unit which is connected to the metering pump in terms of fluid communication on the suction side of the metering pump, wherein the pressure monitoring unit has at least one, in particular the further, pressure sensor which is arranged on at least one tank element of the tank unit. The tank unit, in particular the tank element, is preferably fluidically connected to the metering pump, in particular to the product inlet of the metering pump, via the feed line on the suction side of the metering pump. The tank element is preferably designed as a supply container. It is conceivable that the dosing device, in particular in addition to the pressure monitoring unit, comprises a pressure regulating unit for regulating a pressure in the tank element. The pressure sensor and the further pressure sensor are preferably arranged in a region between a filler neck of the tank element and the product inlet of the metering pump. The tank element can preferably be filled with liquid and / or pasty products via the filler neck. The configuration according to the invention advantageously allows reliable monitoring of a change in product properties which could lead to high closure of the metering pump and / or which could lead to impairment of filling of the product to be metered. Damage to the product to be metered can be advantageously counteracted by a delivery pressure that is too high, for example. Furthermore, an advantageous inline process control on the metering device can be made possible.It is furthermore proposed that the, in particular further, pressure sensor of the pressure monitoring unit is arranged in a product receiving space of the tank element, in particular on an upper side of the product receiving space. The further pressure sensor is preferably arranged on an inner side of the tank element, which is opposite an outlet opening of the tank element. The outlet opening is preferably connected fluidically to the feed line. However, it is also conceivable for the further pressure sensor to be arranged at another position that appears expedient to a person skilled in the art, in particular within the tank element. By means of the configuration according to the invention, pressure characteristics can be detected particularly reliably in a vicinity of the metering pump, which pressure characteristics can be used in a meaningful manner for monitoring a change in product properties. It is advantageously possible to reliably detect a monitoring of a change in product properties which could lead to high wear of the metering pump and / or which could lead to an impairment of a filling of the product to be metered. Damage to the product to be metered can be advantageously counteracted by a delivery pressure that is too high, for example. Furthermore, an advantageous inline process control on the metering device can be made possible.It is further proposed that the, in particular further, pressure sensor of the pressure monitoring unit is arranged above a filling opening, which opens into the product receiving space, of a filling connector, in particular of the already previously mentioned, of the tank element. The configuration according to the invention advantageously makes it possible to have little influence on a detection of pressure parameters by a filling process of the tank element. A reliable detection of pressure parameters can advantageously be realized.It is furthermore proposed that the metering device comprises at least one arithmetic unit, in particular the arithmetic unit already mentioned above, for controlling or regulating an operation of the metering unit, wherein the arithmetic unit determines a maximum differential pressure and / or a static pressure as a function of detected pressure characteristics of the pressure monitoring unit, by means of which a change in product properties of the product to be metered can be determined by the arithmetic unit in order to initiate a warning message output and / or to change at least one operating parameter for controlling the metering pump. The warning message output can be an acoustic, a visual and / or a haptic output. The metering device preferably comprises at least one output unit for outputting the warning message output. A "computing unit" is to be understood in particular as a unit having an information input, an information processing and an information output. The computing unit advantageously has at least one processor, a memory, input and output means, further electrical components, an operating program, control routines, control routines and / or calculation routines. The components of the computing unit are preferably arranged on a common printed circuit board and / or advantageously arranged in a common housing. The arithmetic unit also serves in particular for controlling and / or regulating the changeover valve and / or the metering pump. The arithmetic unit serves in particular as a servo regulator. By means of the configuration according to the invention, advantageously reliable monitoring of a change in product properties can be provided. Furthermore, incorrect parameterization can advantageously be avoided. In particular, an advantageously reliable operation of the dosing device can be made possible. Furthermore, a parameter set counteracting the change in the product property of the product to be metered can advantageously be selected for controlling the metering pump, in particular automatically, or at least one warning can be output to an operator that another parameter set should be selected for controlling the metering pump. This advantageously makes it possible to counteract wear of the metering unit. Damage to the product to be metered can be advantageously counteracted by a delivery pressure that is too high, for example. An advantageous monitoring of a dose setting of the dosing unit can be made possible. Furthermore, an advantageous inline process control on the metering device can be made possible.Furthermore, a production plant, in particular a filling plant, with at least one metering device according to the invention is proposed. The production plant can comprise further devices and / or units that appear expedient to a person skilled in the art and that can be used for handling products, in particular food. The production plant is preferably provided for the production, filling, packaging and / or outer packaging of foods. In addition to the metering device, the production system can have a multiplicity of further devices and / or units which a person skilled in the art deems to be expedient, such as, for example, a forming device for packaging, a cutting device, a filling device, a sterilisation device, a closure device, a repacking device, a container feed device or the like. By means of the configuration according to the invention, a production system with a process-safe metering of liquid and / or pasty products can advantageously be made possible. Automated monitoring of a change in product properties of products to be dosed can advantageously be achieved. Furthermore, an advantageous inline process control on the metering device can be made possible. Advantageously, an incorrect selection or incorrect setting of a parameter set for controlling the metering pump, which is carried out manually by an operator, can be detected at an early stage in order to be able to avoid damage resulting therefrom.The invention furthermore relates to a method for operating a dosing device, in particular a dosing device according to the invention. It is proposed that in at least one method step, pressure characteristics are recorded in the dosing device by means of a pressure monitoring unit of the dosing device, which is arranged, in particular completely, on a suction side of at least one dosing pump of a dosing unit of the dosing device, in order to determine changes in product properties of products to be dosed. By means of the configuration according to the invention, automated monitoring of a change in product properties of products to be dosed can advantageously be achieved. An advantageous monitoring of a dose setting of the dosing unit can be made possible. Furthermore, an advantageous inline process control on the metering device can be made possible.It is furthermore proposed that in at least one method step of the method according to the invention, a maximum differential pressure and / or a static pressure are / are determined from the detected pressure characteristics of the pressure monitoring unit by means of at least one arithmetic unit of the metering device. The embodiment of the dosing device according to the invention advantageously allows reliable dosing of liquid and / or pasty products. Damage to the product to be metered can be advantageously counteracted by a delivery pressure that is too high, for example.It is also proposed that in at least one method step of the method according to the invention, a change in product properties of the product to be metered is inferred by the arithmetic unit as a function of a deviation of the determined maximum differential pressure and / or the determined static pressure from predefined limit values, wherein a warning message output is initiated by the arithmetic unit and / or at least one operating parameter for actuating the metering pump is / is changed by the arithmetic unit. By means of the configuration according to the invention, it is advantageously possible to select a parameter set for actuating the metering pump, in particular automatically, which set counteracts the change in the product property of the product to be metered, or to output at least one warning to an operator that another parameter set should be selected for actuating the metering pump.The metering device according to the invention, the production plant according to the invention and / or the method according to the invention are / is not intended to be limited to the application and embodiment described above. In particular, the metering device according to the invention, the production plant according to the invention and / or the method according to the invention can / can have a number which differs from a number of individual elements, components and units and method steps mentioned herein in order to fulfil a mode of operation described herein. In addition, in the value ranges specified in this disclosure, values lying within the stated limits should also be considered as disclosed and usable as desired.DRAWINGSFurther advantages are evident from the following description of the drawings. The drawings illustrate an embodiment of the invention. The drawings, specification and claims contain numerous features in combination. The skilled person will expediently also consider the features individually and summarize them to form meaningful further combinations.The following are shown: FIG. 1 shows a production plant with at least one metering device according to the invention in a schematic illustration, FIG. 2 shows a detail view of the metering device according to the invention in a schematic illustration, FIG. 3 shows a partial sectional view of the metering device according to the invention with a pressure monitoring unit in a schematic illustration, and FIG. 4 shows a flow diagram of a method according to the invention for operating a metering device in a schematic illustrationDESCRIPTION OF THE EMBODIMENTFIG. 1 shows a production plant 40 with at least one metering device 10 for metering liquid or pasty products, in particular food. The production plant 40 is preferably designed as a filling plant. The production plant 40 is preferably provided for the production and / or processing of products, in particular food. The production plant 40 can be designed, for example, as a food packaging machine, as a food filling machine, as a food production machine, as a combination of the aforementioned machines or the like. The production plant 40 can have further devices and / or units which appear expedient to a person skilled in the art and which are used for the production and / or processing of products, in particular foods, such as, for example, a sterilization device, a filling device, a closure device, a repacking device, a container feed device or the like.FIG. 2 shows a detailed view of the dosing device 10 for dosing liquid or pasty products, in particular food, into containers (not shown in detail here), in particular into cup-shaped containers. The dosing device 10 comprises at least one dosing unit 12, preferably a plurality of dosing units 12. In a description of a single one of the dosing units 12 listed herein, this description preferably relates to all dosing units 12. The metering pump 14 comprises at least one suction side 16 and at least one pressure side 18. Furthermore, the dosing device 10 preferably comprises a computing unit 38. The computing unit 38 is provided at least for controlling and / or regulating the dosing unit 12.In the exemplary embodiment described here, the dosing device 10 comprises, for example, eight dosing units 12. However, it is also conceivable for the dosing device 10 to comprise a different number of dosing units 12 that appears expedient to a person skilled in the art, in particular a number that is useful for a specific field of application of the dosing device 10. The dosing units 12, in particular aligned with one another, are preferably arranged in a row on a base element 50 of the dosing device 10 (cf. FIG. 2 ). The dosing units 12 are preferably fixed to the base element 50 by means of a form-fit and / or force-fit connection, such as for example by means of a screw connection, a clamping connection, a latching connection or the like, in particular individually fixed to the base element 50. The base element 50 preferably comprises at least one aperture for passing through metering nozzles 52 of the metering units 12 (cf. FIG. 3 ). The metering nozzles 52 of the metering unit 12 are preferably fixed on the metering unit 12 so as to be replaceable individually. In the exemplary embodiment shown here, the base element 50 has a plurality of individual apertures, wherein each individual aperture is assigned an individual metering nozzle 52 of an individual metering unit 12. However, it is also conceivable for the base element 50 to have an, in particular central, aperture, to which a plurality of, in particular all, metering nozzles 52 of the metering unit 12 are assigned, in particular through which all metering nozzles 52 of the metering units 12 extend. The metering nozzles 52 of the metering unit 12 can all have an identical configuration or be configured differently. The metering nozzles 52 are preferably designed to be individually replaceable. The metering nozzles 52 can be designed as a flat valve nozzle, as a screw slide nozzle, as a rotary slide nozzle or as another metering nozzle 52 that appears expedient to a person skilled in the art. The base element 50 is preferably arranged on, in particular fixed to, the dosing units 12 on a side of the dosing units 12 facing the dosing nozzles 44 of the dosing units 12.The dosing device 10 preferably comprises at least one tank unit 30, which has at least one tank element 32, in which the liquid / n or pasty / n product / s can be arranged. A mixer unit is preferably arranged on the tank unit 30 in a manner already known to a person skilled in the art. The dosing units 12 are preferably individually connected to the tank element 32 via, in particular individual, feed lines 54 of the dosing device 10. It is also conceivable for the tank unit 30 to comprise a plurality of tank elements 32, wherein different products can be arranged in the individual tank elements 32, which products can be conveyed by means of the metering units 12 into containers in order to enable multi-layer products or products with different components, such as a puddle with a cream hood, which is filled in a cup, or the like. In an embodiment of the tank unit 30 with a plurality of tank elements 32, a single tank element 32 is preferably assigned to each metering unit 12 of the tank unit 30. Furthermore, it is also conceivable that the metering units 12 can be supplied individually or jointly with products via a pipeline system of the production plant 40 and the products are stored in remote silos or the like. Further embodiments and / or distributions of the tank unit 30 and of the dosing units 12 that appear expedient to a person skilled in the art are likewise conceivable.Furthermore, the dosing device 10 has a drive unit 56. The drive unit 56 preferably comprises a plurality of drives for driving the dosing units 12. The drives are preferably designed as servo drives. In the exemplary embodiment shown in the figures, the drive unit 56 comprises four drives, wherein two drives are provided for a piston drive of the metering units 12, in particular of the metering pumps 14 of the metering units 12, and two drives are provided for a valve drive of the metering units 12, in particular of the changeover valves 58 of the metering units 12. However, it is also conceivable for the drive unit 56 to each comprise an individual drive per piston and per switching valve 58. The drive unit 56 preferably comprises one clutch element per drive, wherein the respective clutch element connects four drive elements, in particular drive shafts, of the metering units 12 to one another. Preferably, four piston drive shafts of the dosing units 12 per drive and four valve drive shafts of the dosing units 12 per drive are connected to one another in a drive-related manner via one of the coupling elements in each case. However, it is also conceivable for an individual drive of the drive unit 56 to be provided per piston drive shaft and per valve drive shaft in order to realize an individual drive of the respective piston drive shaft and the respective valve drive shaft. The valve drive shafts are each provided to move a valve rod of one of the switching valves 58, in particular axially. The piston drive shafts are each provided for axially moving a piston rod of one of the metering pumps 14.The dosing device 10 further comprises at least one pressure monitoring unit 20 for detecting at least one pressure characteristic variable. The pressure monitoring unit 20 is arranged along a conveying direction 22 of the metering pump 14, in particular completely, on the suction side 16 of the metering pump 14 (cf. FIG. 3 ). Preferably, the pressure monitoring unit 20 is arranged along the conveying direction 22 of the metering pump 14 in its entirety on the suction side 16 of the metering pump 14. The pressure monitoring unit 20 is arranged along the conveying direction 22 of the metering pump 14 in its entirety preferably upstream of the metering unit 12. Preferably, in particular all, components and / or assemblies of the pressure monitoring unit 20 are arranged along the conveying direction 22 of the metering pump 14 on the suction side 16 of the metering pump 14. The pressure side 18 of the metering pump 14 is preferably free of components and / or assemblies of the pressure monitoring unit 20 along the conveying direction 22 of the metering pump 14. Preferably, a region of the metering pump 14 between the suction side 16 and the pressure side 18 is free of components and / or assemblies of the pressure monitoring unit 20. Preferably, in particular all, pressure sensors 24, 28 of the pressure monitoring unit 20 are arranged upstream of the metering unit 12 along the conveying direction 22 of the metering pump 12. The pressure characteristic variable / s, which can / are detected by means of the pressure monitoring unit 20, is / are preferably a, in particular maximum, differential pressure and / or a static pressure of the product to be metered in at least one line and / or in at least one receiving container of the metering unit 12, in particular in a region upstream of the metering pump 14. The pressure monitoring unit 20 is preferably provided for detecting the pressure characteristic variable / s, in particular exclusively, before the product to be metered enters the metering pump 14. The pressure characteristic / s can / can be detected by means of the pressure monitoring unit 20 at different times and / or at different positions in the line and / or in the receiving container before the product to be metered enters the metering pump 14. It is advantageously possible to infer a change in product properties of the product to be dosed, in particular since the pressure characteristic / s of the product to be dosed changes, for example, by a friction between the moving product and contact surfaces of the line and / or of the receiving container, wherein this friction can be influenced, for example, by a flow speed of the product to be dosed, by the density of the product to be dosed, by piece components present in the product to be dosed, such as lumps, fruit pieces or the like, and / or further factors. In particular in the area of seals, it is expedient to have a low overpressure in order to advantageously realize a secure pressing of the seals against corresponding counter surfaces.The pressure monitoring unit 20 preferably comprises at least one pressure sensor 24, which is arranged in the vicinity of a product inlet 26 of the metering pump 14 arranged on the suction side 16 of the metering pump 14, and at least one further pressure sensor 28, which is arranged upstream of the pressure sensor 24 along the conveying direction 22 of the metering pump 14 (cf. FIG. 3 ). The pressure sensor 24 preferably has a maximum distance relative to the product inlet 26 of the metering pump 14, which is in particular less than 300 mm, preferably less than 150 mm and particularly preferably less than 75 mm. The pressure sensor 24 is arranged along the conveying direction 22 of the metering pump 14 preferably spaced apart relative to the further pressure sensor 28. In particular, the pressure sensor 24 is arranged along the conveying direction 22 of the metering pump 14 downstream of the further pressure sensor 28. Pressure sensor 24 preferably has a maximum distance relative to further pressure sensor 28, which is in particular less than 3,000 mm, preferably less than 2,000 mm, and particularly preferably less than 750 mm. The pressure sensor 24 and the further pressure sensor 28 can have an identical design or can have different designs. The pressure sensor 24 and / or the further pressure sensor 28 can be designed as a piezoresistive pressure sensor, as a piezoelectric pressure sensor 24, 28, as a capacitive pressure sensor 24, 28 or as another pressure sensor 24, 28 that appears expedient to a person skilled in the art. The pressure sensor 24 and the further pressure sensor 28 are preferably designed as so-called pressure measurement transducers (also known as pressure measurement transducers or pressure transmitters), which are connected via an analog or digital output to the computing unit 38 of the dosing device 10.The metering device 10 preferably comprises at least the tank unit 30, which is fluidically connected to the metering pump 14 on the suction side 16 of the metering pump 14, wherein the pressure monitoring unit 20 has at least one, in particular the further, pressure sensor 28, which is arranged on the at least one tank element 32 of the tank unit 30 (cf. FIG. 3 ). The tank unit 30, in particular the tank element 32, is preferably connected in terms of fluid communication via the feed line 54 on the suction side 16 of the metering pump 14 to the metering pump 14, in particular to the product inlet 26 of the metering pump 14. The tank element 32 is preferably designed as a supply container. It is conceivable that the dosing device 10, in particular in addition to the pressure monitoring unit 20, comprises a pressure regulating unit (not shown in detail here) for regulating a pressure in the tank element 32. The pressure sensor 24 and the further pressure sensor 28 are preferably arranged in a region between a filler neck 36 of the tank element 32 and the product inlet 26 of the metering pump 14, as seen from the flow point of view. The tank element 14 can preferably be filled with liquid and / or pasty products via the filler neck 36 in a manner already known to a person skilled in the art.Preferably, the, in particular further, pressure sensor 28 of the pressure monitoring unit 20 is arranged in a product receiving space 34 of the tank element 32, in particular on an upper side of the product receiving space 34 (cf. FIG. 3 ). The further pressure sensor 28 is preferably arranged on an inner side of the tank element 32, which is opposite an outlet opening of the tank element 32. The outlet opening of the tank element 32 is preferably connected fluidically to the feed line 54. The, in particular further, pressure sensor 28 of the pressure monitoring unit 20 is preferably arranged above a filling opening of the filler neck 36 of the tank element 32, in particular in the product receiving space 34, which opening opens into the product receiving space 34. However, it is also conceivable for the further pressure sensor 28 to be arranged at another position that appears expedient to a person skilled in the art, in particular within the tank element 32.The metering device 10 preferably comprises the at least one arithmetic unit 38 for controlling or regulating an operation of the metering unit 12, wherein the arithmetic unit 38 determines a maximum differential pressure and / or a static pressure as a function of detected pressure characteristics of the pressure monitoring unit 20, by means of which a change in product properties of the product to be metered can be determined by the arithmetic unit 38 in order to initiate a warning message output and / or to change at least one operating parameter for controlling the metering pump 14. The warning message output can be an acoustic, a visual and / or a haptic output. The metering device preferably comprises at least one output unit (not shown in detail here) for outputting the warning message output. In particular, automated monitoring of a change in product properties of products to be dosed can be achieved. Furthermore, a parameter set counteracting the change in the product property of the product to be metered can be selected for controlling the metering pump 14, in particular automatically by means of the arithmetic unit 38, or at least one warning can be output to an operator that another parameter set should be selected for controlling the metering pump 14. This advantageously makes it possible to counteract wear of the metering unit. An incorrect selection or incorrect setting of a parameter set for controlling the metering pump 14 manually carried out by an operator can be detected at an early stage in order to be able to avoid damage resulting therefrom.FIG. 4 shows a schematic flow diagram of a method 42 for operating the dosing device 10. pressure characteristics in the dosing device 10 are preferably recorded in at least one method step 44 of the method 42 by means of the pressure monitoring unit 20 of the dosing device 10 arranged, in particular completely, on the suction side 16 of the dosing pump 14 of the dosing device 12 of the dosing device 10 for determining changes in product properties of products to be dosed. Preferably, in at least one, in particular further method step 46 of the method 42, a maximum differential pressure and / or a static pressure are / is determined by means of the at least one arithmetic unit 38 of the dosing device 10 from the detected pressure characteristics of the pressure monitoring unit 20. Preferably, in at least one, in particular further, method step 48 of method 42, a change in product properties of the product to be metered is inferred by computing unit 38 as a function of a deviation of the determined maximum differential pressure and / or the determined static pressure from predefined limit values, wherein a warning message output is initiated by computing unit 38 and / or at least one operating parameter for actuating metering pump 14 is / is changed. The method 42 for operating the dosing device 10 can have further method steps that appear expedient to a person skilled in the art. In addition, possible method steps that can be derived from the description of FIGS. 1 to 3 are also to be considered as disclosed for the method 42.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2005 044 796 A1

[0004]

Claims

Metering device for metering liquid and / or pasty products, in particular foods, having at least one metering unit (12) which comprises at least one metering pump (14) which has at least one suction side (16) and at least one pressure side (18), and having at least one pressure monitoring unit (20) for detecting at least one pressure characteristic variable, characterized in that the pressure monitoring unit (20) is arranged, in particular completely, on the suction side (16) of the metering pump (14) along a conveying direction (22) of the metering pump (14).The metering device according to claim 1, characterized in that the pressure monitoring unit (20) comprises at least one pressure sensor (24), which is arranged in the vicinity of a product inlet (26) of the metering pump (14) arranged on the suction side (16) of the metering pump (14), and at least one further pressure sensor (28), which is arranged in front of the pressure sensor (24) along the conveying direction (22) of the metering pump (14).The metering device according to claim 1 or 2, characterized byat least one tank unit (30) which is fluidically connected to the metering pump (14) on the suction side (16) of the metering pump (14), wherein the pressure monitoring unit (20) has at least one, in particular the further, pressure sensor (28) which is arranged on at least one tank element (32) of the tank unit (30).The dosing device according to claim 3, characterized in that the, in particular further, pressure sensor (28) of the pressure monitoring unit (20) is arranged in a product receiving space (34) of the tank element (32), in particular on an upper side of the product receiving space (34).Metering device according to Claim 4, characterized in that the, in particular further, pressure sensor (28) of the pressure monitoring unit (20) is arranged above a filling opening, which opens into the product receiving space (34), of a filling connection piece (36) of the tank element (32).Metering device according to one of the preceding claims, characterized byat least one arithmetic unit (38) for controlling or regulating an operation of the metering unit (12), wherein the arithmetic unit (38) determines a maximum differential pressure and / or a static pressure as a function of detected pressure characteristics of the pressure monitoring unit (20), by means of which a change in product properties of the product to be metered can be determined by the arithmetic unit (38) in order to initiate a warning message output and / or to change at least one operating parameter for controlling the metering pump (14).Production plant, in particular filling plant, having at least one metering device according to one of the preceding claims.Method for operating a dosing device, in particular a dosing device according to one of Claims 1 to 6, characterized in that, in at least one method step (44), pressure characteristics are recorded in the dosing device by means of a pressure monitoring unit (20) of the dosing device, which is arranged, in particular completely, on a suction side (16) of at least one dosing pump (14) of a dosing unit (12) of the dosing device, in order to determine changes in product properties of products to be dosed.Method according to Claim 8, characterized in that, in at least one method step (46), a maximum differential pressure and / or a static pressure are / are determined from the recorded pressure characteristics of the pressure monitoring unit (20) by means of at least one arithmetic unit (38) of the metering device.Method according to Claim 9, characterized in that, in at least one method step (48), a change in product properties of the product to be metered is deduced by the arithmetic unit (38) as a function of a deviation of the determined maximum differential pressure and / or of the determined static pressure from predefined limit values, wherein a warning message output is initiated by the arithmetic unit (38) and / or at least one operating parameter for actuating the metering pump (14) is / is changed.

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