US-12624978-B2 - Method for determining a mass flow and conveying and measuring device

Abstract

A method for determining a mass flow of bulk material in a conveyor line includes providing a conveyor line, continuously receiving bulk material, transporting the bulk material on the conveyor line, and discharging the bulk material at an end point of the conveyor line. The conveyor line includes an array of weighing cells having a plurality of weighing cells successive in a direction of transport.

Inventors

• Marius Thiel

Assignees

• CiTEX Holding GmbH

Dates

Publication Date

20260512

Application Date

20230512

Priority Date

20220513

Claims (20)

1. 1 . Method for determining a mass flow of bulk material in a conveyor line, including the following steps: providing a conveyor line including an array of weighing cells consisting of a plurality of weighing cells successive in a direction of transport (ST 1 ), continuously receiving bulk material, transporting the bulk material on the conveyor line in the direction of transport across the plurality of weighing cells, discharging the bulk material at an end point of the conveyor line (ST 2 ), putting out measuring values of the individual weighing cells as a function of time (ST 3 ), evaluating with comparisons of measuring values as a function of time and a position of the weighing cells in the direction of transport, wherein a structure or sequence of measuring values of spatially successive measuring values of a first measurement at a first point in time (t 0 ) is compared with at least one structure or sequence of measuring values of spatially successive measuring values of a second measurement at a second point in time, and a distance value of the two structures or sequences of measuring values is determined from the comparison, and determining a mass flow from the distance value and the time difference between the first point in time and the second point in time (ST 5 ).
2. 2 . Method according to claim 1 , characterized in that distance values of the weighing cells in the direction of transport in relation to one another are included in the determination.
3. 3 . Method according to claim 1 , characterized in that first a transport velocity is determined from the distance value and the time difference and subsequently the mass flow is determined from the transport velocity and the measuring values.
4. 4 . Method according to claim 1 , characterized in that a one-dimensional or multi-dimensional matrix of measuring values is created for each of at least two points in time, creating at least two matrixes, and from the at least two matrixes a pattern recognition and/or a correlation, is carried out to determine matches in the structures or sequences of measuring values.
5. 5 . Method according to claim 1 , characterized in that the array of weighing cells is designed as a one- or multi-dimensional matrix consisting of weighing cells arranged successively in the direction of transport.
6. 6 . Method according to claim 1 , characterized in that the conveyor line is selected from the following group: a belt conveyor, a screw feeder, a vibration conveyor, a deflector plate conveyor, a cellular wheel conveyor.
7. 7 . Method for regulating a mass flow, wherein using a method according to claim 1 a bulk material is transported from the bulk material feed provided at the starting point to a receiving or processing means provided at the end point and measured, and the mass flow on the conveyor line is determined, and the bulk material feed and/or the receiving or processing means is controlled and regulated depending on the determined mass flow.
8. 8 . Method according to claim 7 , characterized in that the bulk material feed is controlled depending on the determined mass flow in such a manner that a prescribed mass flow is adjusted.
9. 9 . Method according to claim 7 , characterized in that the receiving or processing means is controlled depending on the determined mass flow, whose transport velocity or production speed is regulated depending on the mass flow.
10. 10 . Method according to claim 7 , characterized in that the following is fed in as bulk material: a plastics material and/or rubber material, and one or more additives, where the mass flow of the plastics material and/or rubber material and/or the mass flow of the one or more additives is measured and regulated.
11. 11 . Method for determining a mass flow of bulk material in a conveyor line, including the following steps: providing a conveyor line including an array of weighing cells consisting of a plurality of weighing cells successive in a direction of transport (ST 1 ), continuously receiving bulk material, transporting the bulk material on the conveyor line in the direction of transport across the plurality of weighing cells, discharging the bulk material at an end point of the conveyor line (ST 2 ), putting out measuring values of the individual weighing cells as a function of time (ST 3 ), evaluating with comparisons of measuring values as a function of time and a position of the weighing cells in the direction of transport, wherein a one-dimensional or multi-dimensional matrix of measuring values is created for each of at least two points in time, creating at least two matrixes, and from the at least two matrixes a pattern recognition and/or a correlation, is carried out to determine matches in the structures or sequences of measuring values, and wherein with one time difference in each case, the autocorrelation is carried out with different distance values, and the correct distance value is recognized in the autocorrelation with a highest significance, and determining a mass flow from the evaluation (ST 5 ).
12. 12 . Method according to claim 11 , characterized in that distance values of the weighing cells in the direction of transport in relation to one another are included in the determination.
13. 13 . Method according to claim 11 , characterized in that the array of weighing cells is designed as a one- or multi-dimensional matrix consisting of weighing cells arranged successively in the direction of transport.
14. 14 . Method for determining a mass flow of bulk material in a conveyor line, including the following steps: providing a conveyor line including an array of weighing cells consisting of a plurality of weighing cells successive in a direction of transport (ST 1 ), wherein the conveyor line is selected from the following group: a belt conveyor, a screw feeder, a vibration conveyor, a deflector plate conveyor, a cellular wheel conveyor, continuously receiving bulk material, transporting the bulk material on the conveyor line in the direction of transport across the plurality of weighing cells, discharging the bulk material at an end point of the conveyor line (ST 2 ), putting out measuring values of the individual weighing cells as a function of time (ST 3 ), evaluating with comparisons of measuring values as a function of time and a position of the weighing cells in the direction of transport, and determining a mass flow from the evaluation (ST 5 ), wherein a deflector plate conveyor is utilized as the conveyor line; the weighing cells are provided immediately below the deflector plate and/or integrated therein, measuring values of a front weighing cell are used to determine a particle mass of the impinging material, and slippage characteristics are determined as transport velocity from subsequent weighing cells.
15. 15 . Transporting and measuring device for transporting and measuring a mass flow of bulk material, the transporting and measuring device comprising: a conveyor line adapted to transport bulk material as a mass flow (W) from at least one starting point in a direction of transport up to an end point, an array of weighing cells consisting of a plurality of weighing cells, arranged successively in the direction of transport, each detecting a mass load, and outputting measuring values as a function of time, and an evaluation device adapted to evaluate the measuring values as a function of time and a position of the weighing cells in the direction of transport, wherein the evaluation device is designed to compare the structure or sequence of measuring values of spatially successive measuring values of a first measurement at a first point in time with at least one structure or sequence of measuring values of a second first measurement at a second point in time, and to determine a distance value or spatial offset of the two structures or sequence of measuring values from the comparison.
16. 16 . Transporting and measuring device according to claim 15 , characterized in that the conveyor line is designed as a belt conveyor including a conveyor belt under which or integrated in which the plurality of weighing cells is arranged.
17. 17 . Transporting and measuring device according to claim 15 , characterized in that it is designed as a screw feeder including a screw conveyor, the weighing cells being provided in a lower floor area and distributed in areas successive in the circumferential direction.
18. 18 . Transporting and measuring device according to claim 15 , characterized in that at least some of the weighing cells are designed as an element from the group consisting of piezo sensors and/or wire strain gauges, and wherein at least some of the weighing cells are further designed as a coating or part of a coating including individual weighing cells.
19. 19 . Transporting and measuring device according to claim 15 , characterized in that a transmission of the measuring values and/or of energy from and to the weighing cells is provided to be wireless and/or by means of passive transponders.
20. 20 . Transporting and measuring device according to claim 15 , characterized in that the plurality of weighing cells is arranged as a one-dimensional line array or multi-dimensional matrix, including weighing cells successive in the direction of transport.

Description

This application claims priority under 35 U.S.C. § 119 to German Application No. 10 2022 112 046.5, filed May 13, 2022, which is expressly incorporated by reference herein. The invention relates to a method of determining a mass flow as well as a transporting and measuring device. Further, a control method is created. Conveyor lines serve generally for transporting granulated bulk material, for example, pellets, granulate, flakes or grains and are utilized, for example, in a production plant, for example, an extruder, to transport the bulk material continuously from a bulk material feeder towards the processing unit. The granulated bulk material will generally be distributed unevenly across the conveyor line. In part, it will already be received by the bulk material feeder in a discontinuous intermittent manner and forms uneven accumulations of material on the conveyor line. Hereby, the bulk material will tend to agglutinate, also depending on its material characteristics and, for example, on temperature and humidity. However, many applications require exact information on the mass flow, in particular, in a bulk material feed towards a processing unit. Moreover, in some conveyor lines the transport velocity of the material is not known precisely, for example, in the case of vibration feeders, deflector plates, and screw conveyors. In the case of belt conveyors, the actual belt velocity will depend on slippage on the deflection rollers which, in turn, will depend on, e.g., on the tension of the elastic conveyor belt and the load inflicted by the mass. For measuring a fed-in mass flux, gravimetric weighing devices are known, wherein a transporting device is weighed together with the material contained therein so that a measured value is received continuously as a function of time and the mass flux can be determined. The precision of such systems is limited, however. Further, it is known to measure the mass flux in an air flow allowing, in particular, for the detection of the flow velocity, however, without precisely detecting the mass flux conveyed hereby. Conveyor belt weighing devices allow dynamic measuring of a feed rated on a conveyor belt, wherein the weight on the belt can be determined by a weighing cell as a function of time so that a mass flux can be determined. The document DE3540165A1 describes a method and a device for fine metering of bulk materials, wherein a flow of granulated material is detected via weighing cells. The citations EP0533968A1 and DE102005053352A1, too, describe measuring systems, wherein the weight of transported masses is detected via weighing cells. The document DE4414715A1 shows a method for determining the feed rate of a belt scales and a device for executing the method. Hereby, at least two weighing cells are provided at a pre-determined distance, whose weighing signal trajectories are evaluated, where the belt velocity and the distance of the weighing cells are taking into consideration, to put out an error signal. The citation DD229908A1 shows a device for determining a mass flux, where, for one thing, a conveyor belt velocity is determined from signals of mass sensitive sensors by means of a correlation algorithm and, for another, the value of the mass density on the conveyor belt is determined by averaging. The mass throughput is determined by multiplicative linking of conveyor belt velocity and mass density. Furthermore, the sensor monitor each other so as to indicate any failure. In the document DE10103854A1 a measuring device for determining a continuous mass flux of granulated materials is described, consisting of two modular spiral chute parts each resting on three weighing cells. Each spiral chute part consists of a downwards angled spiral onto which a continuous mass flux is supplied. Upon passing of a flux of granulated materials, both the spiral load as well as the flow velocity are determined using the weighing cell signals, and the transport rate and/or the feed rate is calculated from this. The citation DE69226204T2 shows a device for weighing continuous flowing, grainy or pulverized material, wherein the mass flux of the material is determined as a function of measurements of forces exerted on an inclined first plate which lies essentially straight in the direction of flow and onto which the flowing material flows slidingly, where force measuring means support and measure the plate. Thus, the invention is based on the object of creating a method and a transporting and measuring device allowing for a precise determination of a mass flow. This task is solved by a method and a transporting and measuring device according to the independent claims. The sub-claims specify preferred further developments. Moreover, a control method is created utilizing the method. The method for determining a mass flow according to the invention may be carried out, in particular, in the transporting and measuring device according to the invention. Thus, the mass flow on the conve