Method for gravimetric fill level measurement of a spinning preparation machine and spinning preparation machine

Abstract

The present invention relates to a spinning preparation machine (1) for processing fiber flakes (2), wherein the spinning preparation machine (1) can be supported on a stationary floor (3) via several support points (24), comprising: several adjacently arranged filling chutes (5), a feed channel (6) arranged above the filling chutes (5), which is connected on the inlet side to a central fiber flake inlet (9) and has a bottom opening (7) on the outlet side for each filling chute (5), a control unit (37), a weighing device (26) signal-connected to a control unit, which is arranged in the force flow between the filling chutes (5) and the stationary floor (3) and has several load cells (27) which are arranged at a subset of the support points (24), characterized in that the support points (24) provided with the load cells (27) lie on an imaginary connecting line (39),which is aligned parallel to a main axis (38) of the spinning preparation machine (1).

Description

[0001] The present invention relates to a spinning preparation machine that can be filled with fiber flakes, wherein the spinning preparation machine has several filling chutes arranged next to each other, a feeding channel arranged above the filling chutes, which is connected on the inlet side to a central fiber flake inlet and has a bottom opening on the outlet side for each filling chute, a discharge device arranged below the filling chutes, which is connected on the inlet side to the filling chutes and on the outlet side to a central fiber flake outlet, and a weighing device connected to a control unit via a signal.

[0002] From EP 3 587 631 A1, a spinning preparation machine for processing fiber flakes is known, the machine frame of which is supported at least four points on a foundation. At least one load cell for measuring the fill level of a storage container for fiber flakes in the spinning preparation machine is provided between the machine frame and the foundation.

[0003] US Patent 2004255429 discloses a fiber metering device for introducing fibers into concrete. The device has a frame to support the fiber dispensing device. Several load cells are mounted between the frame and a conveying housing of the fiber metering device, with two of the load cells located on a connecting line transverse to the axis of movement defined by the direction from a fiber inlet of the device to a fiber outlet of the device.

[0004] Using a spinning preparation machine mounted on load cells, the fill weight of the fiber flocks can be precisely determined based on the machine's empty weight. However, knowing the fill weight alone is not always sufficient to prevent individual feed hoppers from running empty in spinning preparation machines with multiple hoppers, as the fiber flocks can be distributed very unevenly across these hoppers. As soon as one of the feed hoppers runs empty, this disrupts the production of the spinning preparation machine.

[0005] The object of the present invention is to provide a spinning preparation machine that can be filled with fiber flakes, is simple in design and enables a simplified gravimetric level calculation of the spinning preparation machine.

[0006] To solve the problem, a spinning preparation machine for processing fiber flakes is proposed, wherein the spinning preparation machine can be supported on a stationary floor via several support points and comprises several adjacent filling chutes, a feed channel arranged above the filling chutes, which is connected at the inlet side to a central fiber flake inlet and has a bottom opening at the outlet side for each filling chute, a control unit, and a weighing device connected to a control unit via a signal, which is arranged in the force flow between the filling chutes and the stationary floor and has several load cells arranged at a subset of the support points. In the spinning preparation machine according to the invention, the support points equipped with the load cells lie on an imaginary connecting line that is aligned parallel to a main axis of the spinning preparation machine.

[0007] According to the invention, the support points equipped with the load cells are thus arranged only on one side of the machine along the main axis of the spinning preparation machine, which runs parallel to the longitudinal axis.

[0008] Experiments have shown that, over the long term, the flake material distributes itself uniformly in the filling chutes along an axis perpendicular to the main axis, so that a long-term symmetrical weight distribution across the clear frame span can be assumed, or indeed is already present. This simplifies the static calculation to a simply supported beam, which is a particularly easy element to calculate in statics, and whose support reactions can be determined without complex calculation methods. Accordingly, the spinning preparation machine according to the invention has the advantage that the support reactions resulting from the changing filling conditions during operation of the spinning preparation machine at the support points can be determined with minimal computational effort.

[0009] In one possible embodiment of the spinning preparation machine, several closing devices, adjustable by means of actuators, can be arranged in the feeding channel. The control unit can be configured to actuate the actuators for filling the filling chutes with fiber flakes in such a way that, due to the position of the closing devices, only one of the bottom openings is connected to the central fiber flake inlet at any given time. A discharge device, connected to the filling chutes on the inlet side and to a central fiber flake outlet on the outlet side, can be arranged below the filling chutes.

[0010] The closing devices can be designed as pivotable flaps, rotary valves, etc., which can be arranged in the feed channel. In particular, each closing device can be moved into at least two positions. In a closed position, the respective closing device blocks the corresponding bottom opening in the feed channel, so that the filling shaft adjoining the corresponding bottom opening cannot be filled. InIn the open position, the respective closing device releases the bottom opening associated with it, allowing filling of the connected filling chute. The feed channel is blocked downstream of the now-released bottom opening by the closing device in the open position. Due to this arrangement of the closing devices, the last bottom opening in the feed channel in the feeding direction does not require a closing device. In other words, it is sufficient if (n) closing devices are provided for (n) bottom openings. As a result, only one of the bottom openings can be connected to the central fiber flake inlet at any given time. Preferably, simultaneous filling of multiple filling chutes is not possible.

[0011] The spinning preparation machine can, for example, be a fiber mixer designed as a shaft mixer. This can have several filling chutes arranged side by side or one behind the other in a feeding direction. The fiber flakes can be fed into the individual filling chutes via the feed channel running above the filling chutes. The fiber flakes can be transported pneumatically, for example, by means of one or more fans connected to the feed channel. A closing device, such as a flap, particularly a rotary valve, can be arranged in the feed channel for each filling chute, and these closing devices can be opened and closed via the control unit. For this purpose, each closing device can interact with the respective actuator, which can be coupled to the control unit.Furthermore, the spinning preparation machine can have a discharge device consisting of rollers on the underside of the feed hoppers to empty the hoppers. All feed hoppers can be emptied simultaneously. The discharge device can comprise the feed rollers and downstream discharge rollers in a manner known per se. A suction system, for example one operating with a fresh air supply, can be connected below the discharge device to transport the mixed fiber flakes to the next processing machine, in particular another spinning preparation machine.

[0012] In particular, the spinning preparation machine has at least three and preferably at least four support points for placement on a stationary floor. Specifically, the spinning preparation machine has a substructure and a machine frame, the machine frame being supported against the stationary floor by means of the substructure. To align the machine frame with the floor, the substructure may, in particular, have height-adjustable support feet. The filling chutes may be attached to the machine frame.

[0013] For reliable level measurement, the mass can be determined by gravimetric measurement using the weighing device, which preferably comprises several load cells. Due to the design of the spinning preparation machine, measuring the entire machine may be advantageous. While shaft-by-shaft measurement is also possible in principle when configured as a mixer, measuring the entire machine and calculating the individual shaft fill levels is preferred.

[0014] The load cells can, for example, be designed as shear beam load cells. In particular, the base body of such a load cell is designed as a spring element and is made of a metal that deforms under force and returns to its original state when the force is removed. This defined deformation can be registered via a strain gauge attached to the base body and converted into an electrical signal.

[0015] Furthermore, in their simplest form, load cells can also include strain gauges, which can be attached directly to load-bearing supports of the substructure of the spinning preparation machine. Filling or emptying the filling chutes creates a mechanical load on the substructure, which causes material deformation, for example in the support feet, and this deformation can be detected by the load cells.

[0016] According to one embodiment, the load cells can be arranged between the machine frame and the stationary floor.

[0017] According to a further embodiment, the spinning preparation machine can have a decoupling device with at least four support points for placement on a stationary floor, wherein the machine frame and the decoupling device are structurally separated from each other, and the load cells are arranged between the decoupling device and the machine frame.

[0018] To eliminate disturbances that could affect the measuring accuracy of the weighing device, pipes for feeding and extraction, such as a fiber flock inlet and / or outlet, through which the spinning preparation machine can be connected to upstream or downstream spinning preparation machines, can be decoupled. This prevents force bypass. This decoupling can be achieved, for example, using seals, flexible hose sections, and the like. A maintenance platform of the spinning preparation system, which may be permanently attached to the spinning preparation machine, can also be decoupled to prevent additional loads and vibrations on the weighing device when accessing the platform, and thus eliminate force bypass.

[0019] In one possible configuration, the spinning preparation machine can be configured to perform a gravimetric level measurement procedure that includes the following steps: 1) Measuring a change in weight force using the weighing device (26) in a defined time interval during a filling and / or emptying process; 2) Calculating a change in the filling weight of the filling chutes (5) by the control unit (37) from the change in weight force in the defined time interval; 3) Calculating the filling levels of the filling chutes (5) by the control unit (37), wherein the change in filling weight is distributed to the at least one filling chute (5) that was connected to the fiber flake inlet (9) in the defined time interval due to the positions of the closure devices (11).

[0020] A key advantage is that the control unit manages the actuators and therefore knows the positions of the shut-off devices. This allows the control unit to consider, when calculating fill levels, which of the filling chutes was connected to the fiber flake inlet and for how long during the defined time interval. The weighing device also provides the control unit with information about how the weight force changed during that time interval. Accordingly, the control unit can allocate the incoming quantity of fiber flakes, or their weight, proportionally to the individual filling chutes, taking into account the information from the shut-off device positions. In this way, the control unit can calculate the fill level of each individual filling chute.

[0021] During the filling process, material is fed into the hoppers, ensuring that at least one of them is filled with fiber flakes. The discharge mechanism remains stationary during this process, preventing any fiber flakes from being drawn from the hoppers. During the emptying process, no material is fed into the hoppers, and the discharge mechanism removes the fiber flakes from the hoppers. During both the filling and emptying process, material is fed into the hoppers, and the discharge mechanism removes fiber flakes from the hoppers.

[0022] The weighing device measures a weight force from which a total weight can be calculated. The total weight consists of an empty weight and a filled weight. Because the weighing device is positioned in the force path between the filling chutes and the stationary floor, the total weight does not necessarily correspond to the total mass of the spinning preparation machine.

[0023] In particular, the change in weight force corresponds to the difference between the weight force measured at a starting point of the time interval and the weight force measured at an end point of the time interval. The change in weight force thus has the same physical unit as weight force. The weighing device and / or the control unit can preferably convert or display the force value in kilograms. Similarly, the change in fill weight can correspond to the difference between the fill weight at the starting point of the time interval and the fill weight at the end point of the time interval. The change in fill weight thus has the same physical unit as fill weight, namely kilograms. The fill weight corresponds to the difference between the weight measured by the weighing device and the empty or tare weight, which may be stored in the control unit.The latter occurs when the filling chutes are empty, or rather, when there are no fiber flakes in the spinning preparation machine. The empty weight can be measured using the weighing device or stored as a preset value in the control unit.

[0024] The mass of the fiber flakes is thus used to calculate the fill level. Compared to, for example, height measurement, which can be carried out using light barriers installed in the filling chutes, this offers the following advantages: direct comparability with other information from tests or measuring systems in the spinning mill (for example, bale weight displayed for the bale opener); independence from material compression in the filling chutes by compressed air or filling weight; independence from changing material properties, such as packing density; and independence from material distribution in the filling chute. The fill levels can be expressed in kilograms. Therefore, the fill level of the respective filling chute can indicate the quantity of fiber flakes in that chute in kilograms.This is advantageous because it allows for the simple specification of a minimum value, i.e., a minimum fill level, and / or a maximum value, i.e., a maximum fill level. This is particularly beneficial when the spinning preparation machine is to process different materials consecutively, for example, first cotton fiber flakes and, after a material change, fiber flakes made of blended fibers, which may also include recycled fibers. The values ​​can be stored in the control unit or set or changed by an operator of the spinning preparation machine.

[0025] Furthermore, it may be provided that the aforementioned process steps 1) - 3) are repeated during the filling and / or emptying process. In particular, process steps 1) - 3) are repeated continuously. This ensures that the current fill levels are always known. The time interval can be, for example, 1 second, 2 seconds, 3 seconds, 4 seconds, 5 seconds, or even more than 5 seconds or less than 1 second. Preferably, the time interval lies in a range between 1 second and 10 seconds.

[0026] To further optimize the calculation of fill levels, the discharge device can be configured to have a pair of feed rollers per filling chute. The control unit takes the feed roller rotational speed of these pairs into account when calculating the fill levels. This allows for the precise determination of the weight of fiber flakes exiting the filling chutes within a given time interval. The incoming weight for each time interval can be determined by calculating the difference between the change in fill weight and the outgoing weight. This increases the accuracy of the calculated fill level values. The control unit also monitors the status of the feed rollers. This provides information on whether the feed rollers are rotating or stationary. If the feed rollers are rotating, the filling chutes are emptied. If the feed rollers are stationary, no fiber flakes are discharged from the filling chutes.Preferably, the feed rollers are coupled to a common drive. Two feed rollers can be arranged in each filling chute. Alternatively, each filling chute can have its own individual drive, which powers the feed rollers of that chute. Preferably, the rollers of the feed roller pairs are driven at the same speed. In this way, the fiber flakes are taken from all filling chutes simultaneously, ensuring better mixing of the fiber flakes in the mixing channel. Furthermore, the drive train that powers all feed roller pairs is simpler to implement. However, it is also possible for each feed roller pair to be driven individually.

[0027] Specifically, the control unit calculates the production of the spinning preparation machine based on the change in weight force, measured by the weighing device during a time window when no material is being fed into the feed hoppers. This calculation is based on the feed roller speed. The production figure indicates the weight of the fiber flock output per unit of time from the spinning preparation machine. Production is typically expressed in kilograms per hour.

[0028] InTests have shown that production remains constant at fill levels where the individual filling chutes are filled between approximately 30 percent and 100 percent of their maximum capacity. Using the method for calculating the fill levels of the individual filling chutes, the chutes can therefore be filled precisely. This prevents the individual chutes from running dry or the fill level from falling below the predefined minimum value, which could be, for example, 40 percent of the maximum capacity.

[0029] To optimize the control of the overall process in spinning preparation, the total fill level of the spinning preparation machine can be used, for example, to calculate maintenance windows together with the carding mass flow rate, to determine changeover times between lines, and to offer added value / safety for the customer. In particular, the total fill level corresponds to the fill weight. This is especially advantageous when the spinning preparation machine is designed as a mixer, particularly a shaft mixer.

[0030] Further information obtained from the spinning preparation machine or available to the control unit, which can be used for further optimization of the fill level measurement, could include, for example, pressure values ​​from pressure measurements. The limit state, which signifies 100% filling of the respective filling chute, can be determined via the measured differential pressure between the feed and the extraction point and can be verified by light barrier signals from photoelectric sensors, light sensors, etc., installed in the filling chutes.

[0031] Preferred embodiments are explained below with reference to the drawing figures. In With reference to the description of the figures, the same reference symbols can be used in the individual figures to refer to similar or technically equivalent elements. This shows: Figure 1 is a longitudinal sectional view of a spinning preparation machine according to a first embodiment of the present invention; Figure 2 is a Figure 1 Figure II (circled) in enlarged view; Figure 3 is a top view of the spinning preparation machine with a weighing system according to one embodiment; and Figure 4 is a top view of the spinning preparation machine with the weighing system according to a further embodiment; Figure 5 is a flowchart for a method for gravimetric level measurement of the spinning preparation machine; and Figure 6 is a longitudinal sectional view of a spinning preparation machine according to a second embodiment of the present invention.

[0032] In the Figure 1 A spinning preparation machine 1 for processing fiber flakes 2 according to a first embodiment is shown, which is designed as a shaft mixer and can be integrated into a cleaning line of a spinning mill in a manner known per se.

[0033] To illustrate the orientation of the spinning preparation machine 1 in space, the following is shown in the Figure 1 A longitudinal direction X, a transverse direction Y, and a vertical direction Z are drawn, defined in terms of a Cartesian coordinate system assigned to the spinning preparation machine 1 and indicated by corresponding arrows. Terms such as "below," "below," "above," or "above" represent spatial information with respect to the vertical direction Z. The spinning preparation machine 1 can be set up on a fixed base 3, which lies in a horizontal plane spanned by the longitudinal direction X and the transverse direction Y.

[0034] The spinning preparation machine 1 has a flake storage unit 4, which is divided into several, here by way of example, six filling chutes 5 (5.1, 5.2, 5.3, 5.4, 5.5, 5.6) arranged side by side or one behind the other in a feeding direction A. The feeding or transport direction of the fiber air stream is shown in the Figure 1 indicated by arrow A. The filling shafts 5 are spatially separated from each other by perforated partition walls 33.

[0035] Above the filling chutes 5, a feeding device is arranged with a feeding channel 6 and closing elements 11 (11.1, 11.2, 11.3, 11.4, 11.5) located in the feeding channel 6. The filling chutes 5 are connected to the feeding channel 6, which runs above them and has a bottom opening 7 (7.1, 7.2, 7.3, 7.4, 7.5, 7.6) in each filling chute 5 for filling the chutes 5 with fiber flakes 2. An inlet 8 of the feeding channel 6 is flow-conductingly connected to a central fiber flake inlet 9, which is tubular in design and can itself be connected at its inlet end to an upstream spinning preparation machine (not shown). The fiber flakes 2 are pneumatically transported through the fiber flake inlet 9 by means of a fan 10 through the inlet 8 into the feed channel 6.

[0036] In the feed direction A, between the inlet 8 and the bottom openings 7, a recirculation flap 41 is arranged in the feed channel 6, which, in its open position, provides a flow-conducting connection between the inlet 8 and a recirculation channel 40. In the open position, the recirculation flap 41 is pivoted into the feed channel 6 and blocks it downstream of the recirculation flap 41. Figure 1The recirculation damper 41 is shown in its closed position, in which it blocks the recirculation duct 40 and opens the feed duct 6. The recirculation damper 41 can be moved from the open to the closed position, and vice versa, by means of an actuator. When material is required, the recirculation damper 41 is in its closed position to allow the filling chutes 5 to be fed with the fiber flakes 2. When there is no material requirement, the recirculation damper 41 is moved to its open position, in which the transport air, which then does not carry any fiber flakes, is directed past the filling chutes 5 via the recirculation duct 40.

[0037] The positions of the closing elements 11 arranged in the feed channel 6 are adjustable by means of actuators 36. The actuators 36 can be pneumatic, although alternatives such as electromechanical or hydraulic actuators are also possible. Furthermore, the spinning preparation machine 1 has a control unit 37 configured to control the actuators 36 for the targeted filling of the filling chutes 5 with the fiber flakes 2 such that, due to the positions of the closing elements 11, only one of the bottom openings 7 is connected to the central fiber flake inlet 9 at any given time. For the six filling chutes 5, only five closing elements 11 are required due to the arrangement of the closing elements 11.Furthermore, the control unit 37 is configured to actuate the actuator of the recirculation flap 41 in order to move the recirculation flap 41 to its closed position when material is requested, so that the fiber flakes 2 can flow through the inlet 8 towards the respective released bottom opening 7. Each of the closing elements 11 can be moved into two positions by means of the associated actuator 36, namely into its open position and into its closed position, as described in detail below.

[0038] Specifically, at the bottom openings 7.1, 7.2, 7.3, 7.4, 7.5 of the first five filling shafts 5.1, 5.2, 5.3, 5.4, 5.5 in the feed direction A, one of the closing devices 11.1, 11.2, 11.3, 11.4, 11.5 is arranged in each of the following: Figure 1It is shown that, based on a given material requirement, the fiber flakes 2 are transported by means of the transport air A flowing in the feed direction A through the fiber flake inlet 9 into the feed channel 6. The recirculation flap 41, which is in its closed position, blocks the recirculation channel 40 and opens the feed channel 6. The first closing element 11.1 in the feed direction A is in its open position, so that the fiber flakes 2 flowing into the feed channel 6 through the inlet 8 flow through the first bottom opening 7.1 into the first filling chute 5.1. The first closing element 11.1 is pivoted into the feed channel 6 in its open position such that the feed channel 6 is blocked downstream of the first bottom opening 7.1 by the first closing element 11.1. This means that the fiber flakes 2 can only be transported into the first filling chute 5.1.

[0039] When the second filling chute 5.2 is to be filled, the first closing device 11.1 is moved to its closed position, in which it blocks the first bottom opening 7.1 and opens the feed channel 6 downstream of the first bottom opening 7.1. The second closing device 11.2 is then moved to its open position, in which the fiber flakes 2 flowing into the feed channel 6 through the inlet 8 flow into the second filling chute 5.2 through the second bottom opening 7.2, and the feed channel 6 downstream of the second bottom opening 7.2 is now blocked by the second closing device 11.2. The filling of the other filling chutes 5.3, 5.4, and 5.5 is carried out in an analogous manner.

[0040] Only at the last bottom opening 7.6 is none of the closing devices 11 provided. When the last filling shaft 5.6 is to be filled, the closing devices 11.1, 11.2, 11.3, 11.4, 11.5 at the upstream bottom openings 7.1, 7.2, 7.3, 7.4, 7.5 must be moved to their closed positions, in which the upstream bottom openings 7.1, 7.2, 7.3, 7.4, 7.5 are closed and the feed channel 6 is opened.

[0041] At a lower end of the flake storage unit 4, a discharge device 34 is provided, which has a metering device 12 for each filling chute 5 in order to empty the respective filling chute 5 in a controlled manner. Each metering device 12 has a pair of feed rollers 35 with two feed rollers 13, 14 and may further include an opening roller 15 arranged below the pair of feed rollers 35. All feed rollers 13, 14 can be driven by a common drive and preferably rotate at the same input roller speed. In particular, the fiber flakes 2 are simultaneously removed from the filling chutes 5 via the discharge device 34.

[0042] Furthermore, an extraction system, for example one operating with a fresh air supply L, can be connected below the extraction device 34 to transport the mixed fiber flakes 2 to the next processing machine, in particular another spinning preparation machine (not shown) in the cleaning line. For this purpose, a mixing channel 16 can be connected below the metering devices 12, extending longitudinally X across the filling chutes 5, in order to transport the extracted flake material 2 pneumatically via an outlet 17 through a flow-conducting flake discharge 18 to a subsequent spinning preparation machine (not shown) in the cleaning line. The flake discharge 18 can be supported on the stationary floor 3 by a pipe bracket 32.

[0043] Furthermore, the spinning preparation machine 1 has a machine frame 19 to which the flake storage unit 4 with the filling chutes 5, the feed channel 6 arranged thereon, and the discharge device 34, as well as the mixing channel 16, are attached. A machine housing 20 can also be attached to the machine frame 19. The machine frame 19 is supported on the stationary floor 3 by several, here by way of example, four support points 24. In order to align the machine frame 19 with respect to the floor 3, a support foot 25, in particular height-adjustable, is provided at each of the support points 24.

[0044] For gravimetric level measurement, the spinning preparation machine 1 has a weighing device 26 connected to the control unit 37 via a signal, in order to be able to calculate the fill weight of fiber flakes 2 via changes in the measured weight force during operation of the spinning preparation machine 1.

[0045] The weighing device 26 has several load cells 27. The load cells 27 can be arranged at all or at least a subset of the support points 24 between the machine frame 19 and the stationary floor 3. To avoid stresses in the machine frame 19 due to thermal expansion and the associated measurement errors, it is advantageous if the supports allow horizontal displacement, for example by means of damping elements 28.

[0046] The load cells 27 can be arranged directly in the machine frame 19, as is particularly the case in the Figure 2This is evident. This allows them to be integrated into the existing machine structure. The load cells 27 can be arranged between the machine frame 19 and the support feet 25, which are particularly height-adjustable. Accordingly, the machine frame 19 is supported on the support feet 25 via the load cells 27. As shown in the example, the load cells 27 can be attached to an inner surface of a frame profile of the machine frame 19 facing away from the stationary floor 3. Each load cell 27 can be attached to the machine frame 19 at an end facing away from the point of application of the support foot 25. The load cells 27 can, for example, be shear beam load cells. Alternatives are possible, so that the load cell 27 can, for example, be designed as a compression load cell, a bending beam load cell, a double shear beam load cell, or as simple strain gauges. The load cells 27 can be attached to any of the support points 24.Accordingly, the spinning preparation machine 1, when configured with six of the filling chutes 5, can, for example, have four of the load cells 27, and when configured with ten of the filling chutes 5, can, for example, have six of the load cells 27.

[0047] Instead of being integrated into the machine frame 19, the load cells 27 can also be arranged directly on the stationary floor 3 and the support feet 25 can stand on the load cells 27.

[0048] In the Figure 3 Figure 1 shows an embodiment of the spinning preparation machine 1 in which the load cells 27 are provided at all of the support points 24 (here four). To create a defined four-point support and thus enable, for example, calculations based on force and moment equilibria, it is advantageous to provide spring elements at the support points 24, for example, the damping elements 28.

[0049] In the Figure 4 is one to Figure 3An alternative embodiment of the spinning preparation machine 1 is shown, in which the load cells 27 are not arranged at all support points 24, but only at a subset of the support points 24.1, 24.2. The support points 24.1, 24.2 equipped with the load cells 27 are arranged only on one side of the machine along a main axis 38 of the spinning preparation machine 1, which runs parallel to the longitudinal axis X. In particular, the support points 24.1, 24.2 equipped with the load cells 27 lie on an imaginary connecting line 39, which is aligned parallel to the main axis 38. Therefore, no load cells 27 are arranged at the remaining support points 24.3, 24.4, which are located on the other side of the machine.Experiments have shown that the flake material 2 distributes itself uniformly in the filling chutes 5 along the transverse axis Y over the long term, so that a long-term symmetrical weight distribution across the clear span of the frame can be assumed, or indeed is present. This simplifies the static calculation to a simply supported beam, which is a particularly easy element to calculate in statics, and whose support reactions can be determined without complex calculation methods. As a result, the support reactions that arise at the support points 24.1, 24.2, 24.3, and 24.4 due to the changing filling conditions during operation of the spinning preparation machine 1 can be determined with minimal computational effort.In the case of the spinning preparation machine 1, designed as a shaft mixer with the six filling chutes 5 shown here as an example, two of the load cells 27 are sufficient for weight determination. These load cells are arranged on the same side of the machine and on the imaginary connecting line 39, looking along the main axis 38. In the case of the spinning preparation machine 1, designed as a shaft mixer with, for example, ten of the filling chutes 5, three load cells 27 can be provided due to the greater extent along the machine axis, i.e., the machine length. These load cells are also arranged on the same side of the machine and on the imaginary connecting line 39.

[0050] To prevent vibrations from distorting the measurement results obtained with the weighing device 26, and to minimize the introduction of vibration-induced disturbances into the gravimetric level measurement, a vibration-damping element, in this case a flexible hose element 29, is arranged between the machine housing 20 and the fiber flake inlet 9. This element provides a flow-conducting connection between the fiber flake inlet 9 and the inlet 8 into the feed channel 6. Similarly, another vibration-damping element, in this case a further flexible hose element 31, is arranged between the machine housing 20 and the fiber flake outlet 18. This element provides a flow-conducting connection between the mixing channel 16 or the outlet 17 and the fiber flake outlet 18.A platform 30, on which the fan 10 is arranged, can be placed at its bottom end on a vibration-damping element (not shown) for vibration damping. This also prevents a force bypass that would lead to an incorrect, namely too low, weight force being measured by the weighing device 26.

[0051] In the Figure 5 A method for gravimetric level measurement of the spinning preparation machine 1, which can be filled with fiber flakes 2, is simplified and illustrated by a flowchart. Possible embodiments are described below, in which not only information on the positions of the closure devices 11, or the state of the flaps, but also other optional information from the spinning preparation machine 1 is incorporated into the level measurement.

[0052] After starting the process (step 50), the control unit 37 determines the operating mode of the spinning preparation machine 1 in step 51. The operating mode can be manually specified by the user. The spinning preparation machine 1 can, for example, be operated in three different operating modes: filling mode (step 60), empty mode (step 70), and automatic mode (step 80).

[0053] In the filling mode 60, a filling process takes place in which at least one of the filling chutes 2 is filled with the fiber flakes 2 and the discharge device 34 is stationary. The filling mode 60 can be used, for example, to fill the spinning preparation machine 1 with the fiber flakes 2 to produce an initial supply.

[0054] Specifically, in step 61 of the filling operation 60, the control unit 37 queries whether there is a material request. This information can be provided by a higher-level controller, such as a line commander. Furthermore, a material sensor could also be located in the fiber flake inlet 9. As an additional value, the status of the feed rollers 13, 14 can be queried; these should then be switched off. From the weight force (total weight) measured by the weighing device 26 at the beginning of a defined time interval (starting point; t = 0 seconds), minus a predefined empty or tare weight, the fill weight of fiber flakes 2 in the flake storage can be calculated.From the weight force measured at the end of the defined time interval (endpoint; example: t = 5 seconds), the control unit 37 calculates, after subtracting the weight force measured at the starting point, the mass difference resulting from the filling of the filling chutes 5 during the defined time interval. The defined time interval can be, for example, one to five seconds, although longer or shorter intervals are also possible. During operation of the spinning preparation machine 1, the measurement of the change in weight force within the defined time interval is preferably repeated continuously; that is, it always starts again from the beginning, in order to be able to repeatedly calculate the change in filling weight and, based on this, the fill levels of the filling chutes 5. Due to the control of the closure devices 11 described above, only one of the filling chutes 5 can be filled at a time.Thus, in step 62, the control unit 37 can determine which filling chute 5 was open for how long during the defined time interval and which filling chute 5 was therefore filled with the fiber flakes 2. Since only one of the filling chutes 5 can be filled at any given time, the corresponding portion of the measured weight difference can be attributed to the respective filling chute 5.

[0055] In the empty mode 70, an emptying process takes place in which no fiber flakes 2 are fed into the machine and the discharge device 34 removes the fiber flakes 2 from the filling chutes 5. The empty mode 70 can be used, for example, to remove residual quantities of fiber flakes 2 from the spinning preparation machine 1 and, in particular, from the filling chutes 5 during a material change. In other words, no material is requested during the empty mode 70; that is, no fiber flakes 2 enter the feeding channel 6 via the fiber flake inlet 9, and the filling chutes 5 are simply emptied.

[0056] Specifically, in step 71 of the empty operation 70, the control unit 37 queries the status of the feed rollers 13, 14, in particular whether the feed rollers 13, 14 are rotating and at what rotational speed they are driven. In step 72, the control unit 37 calculates the fill levels of the filling chutes 5. For this purpose, the control unit 37 calculates the change in fill weight within the defined time interval, as already described in the example of the filling operation 60. From the change in weight force detected by the weighing device 26, the mass difference is calculated, which is consequently a negative weight difference in the empty operation 70. Because the discharge device 34 simultaneously removes the fiber flakes 2 from all filling chutes 5, the mass difference can be distributed evenly across all filling chutes 5. In other words, the fill level in all filling chutes 5 decreases by the same amount.Due to the identical design of the feed rollers 13 and 14, which are coupled to a common drive, they rotate at the same speed. If, however, the feed rollers 13 and 14 in each filling chute 5 are equipped with their own individual drive, it is possible to determine whether each filling chute 5 is emptying. During empty operation, the filling chutes 5 are thus emptied, with partial or complete emptying of the filling chutes 5 being possible.

[0057] Whenever the filling chutes 5 are not being fed and the fiber flakes 2 are being removed from the filling chutes 5 via the discharge device 34, i.e., during the emptying process only, the control unit 37 can calculate the production of the spinning preparation machine 1 as a function of the feed roller speed during such a time interval. Based on this, the control unit 37 can derive the production for other speeds. For this purpose, for example, speed-dependent production curves can be stored in the control unit 37.

[0058] In the automatic operation mode 80, which is usually present during the operation of the spinning preparation machine 1, the following cases can be distinguished or occur: Filling process (see Filling operation 60); emptying process (see Emptying operation 70); or simultaneous filling and emptying process (see Filling and Emptying operation 60, 70).

[0059] In step 81 of automatic operation 80, the control unit 37 queries the status of the feed rollers 13, 14. If the feed rollers 13, 14 are driven to rotate, the filling chutes 5 are emptied. In step 82, it is also checked whether a material request exists. If a material request exists, filling begins. The actual material flow through the fiber flake inlet 9 into the feed channel 6 can optionally be confirmed by additional sensors in the pipeline, for example, in the fiber flake inlet 9. It is possible that a material request exists in filling mode, but no flake material 2 is currently being delivered from the upstream spinning preparation machine. During this time, weight changes measured by the weighing device 26 could indicate malfunctions.

[0060] During fully automatic emptying (emptying process), the production of the spinning preparation machine 1 is regularly determined by the control unit 37 as a function of the feed roller speed. This is advantageously carried out whenever the filling chutes 5 are as full as possible, i.e., at least 50 percent full. This can be determined, for example, by differential pressure measurements and / or light barriers. Based on the change in the total weight, the production for the respective fiber material 2 can be determined as a function of the feed roller speed.

[0061] During simultaneous filling and emptying, in addition to information on the positions of the closure elements 11, the mass difference measured by the weighing device 26, and the status of the feed rollers 13, 14, the weight distribution between the load cells 27 measured by the weighing device 26 can also be used. This results from the varying filling of the filling chutes 5 along the machine length. The signal from each individual load cell 27 is used separately. During simultaneous filling and emptying in automatic mode, the previously determined production can be used as a function of the feed roller speed. Together with the change in the total weight, the mass of the fed fiber flakes 2 can be determined.

[0062] The mass difference measured by the weighing device 26 during automatic operation in the recurring time interval, which can be, for example, 5 seconds, and which results from the change in the fill weight, is taken into account in step 83 when calculating the fill levels of the filling chutes 5 by the control unit 37, depending on the positions of the closing devices 11 in the respective time interval. The production of the spinning preparation machine 1 is also taken into account, since the fiber flakes 2 are removed via the take-off device 34. Due to the control of the closing devices 11 described above, only one of the filling chutes 5 can be filled at a time. Thus, in step 83, the control unit 37 can determine which of the filling chutes 5 was open for how long in the defined time interval and into which of the filling chutes 5 the fiber flakes 2 were therefore delivered.Since only one of the filling shafts 5 can be filled at any given time, the corresponding proportion of the weight difference measured in the time interval can be attributed to the respective filling shaft 5.

[0063] In step 90, the calculated fill levels of the filling shafts 5 are output, for example on a display at the spinning preparation machine 1 and / or via a data interface for remote displays, for example a portable or stationary terminal device.

[0064] Example sequence of automatic operation 80: Steps 81 and 82 result in no fiber flakes 2 being fed via the fiber flake inlet 9 and the feed rollers 13, 14 rotating. The filling chutes 5 are thus emptied (emptying process). Within the defined time interval, the weight force with which the weighing device 26, in particular the load cells 27, is loaded is measured at the starting point t = 0 and at the end point, here by way of example, after 5 seconds. If all of the support points 24 are equipped with the load cells 27, as in the Figure 3 As shown, the sum of all measured weight forces yields the weight value (total weight). If the load cells 27 are only arranged on one side of the machine, i.e., only half of the support points 24 are equipped with the load cells 27, as shown in the Figure 4As shown, the sum of all measured weight forces multiplied by a factor of 2 yields the weight value (total weight). The filled weight is obtained by subtracting the empty weight from the total weight value. Filling weight 1 at time t = 0 yields m = 100 kilograms [kg] Filling weight 2 at time t = 5 seconds [s] yields m = 99 kg Calculated production: 720 kilograms per hour [kg / h] at current input roller speed, which can, for example, correspond to 70 percent of the maximum input roller speed.

[0065] In the subsequent automatic operation 80, material is fed in; that is, the fiber flakes 2 are fed into the feed channel 6 via the fiber flake inlet 9. In step 83, depending on the position of the closure elements 6, the measured mass difference, i.e., the change in fill weight, can now be distributed to the individual filling chutes 5. The filling chutes 5 are then emptied; that is, the feed rollers 13, 14 are driven to rotate. Thus, the filling chutes 5 are filled and emptied simultaneously (filling and emptying process). In the recurring, defined time interval, the weight force with which the weighing device 26, in particular the load cells 27, is loaded is measured at the start point t = 0 and at the end point, here for example, after 5 seconds, and from this, as described above, the fill weight at the start and end points is calculated. Fill weight 1 at time t = 0 yields m = 100 kg. Fill weight 2 at time t = 5 s yields m = 101 kg. Input roller speed unchanged at roller speed 70 percent results in a production of 720 kg / h (value for the production from the emptying process). Calculation of the change in fill weight: 101 kg − 100 g + 720 kg 3600 s ∗ 5 s = 2 kg In In step 83, the mass difference (change in fill weight) is distributed among the filling chutes 5.1, 5.2, 5.3, 5.4, and 5.5 to calculate the fill levels. For this purpose, the added mass of, in this case, 2 kilograms is assigned to the filling chute 5 that, within the defined time interval, was connected to the central fiber flake inlet 9 based on the position of the closing devices 11. Calculated individual chute fill levels can be regularly checked against pressure signals and / or light barriers as reference points and corrected if necessary.

[0066] In the Figure 6A spinning preparation machine 1 according to a second embodiment is shown, which largely corresponds to the embodiment described above, so that reference is made to the above description regarding the similarities. The difference lies in the design of the substructure on which the machine frame 19 is supported.

[0067] Below the machine frame 19, a decoupling device 21 is arranged, which serves as a base for a machine superstructure 22 comprising the machine frame 19, the flake storage unit 4 with the filling chutes 5 and the feed channel 6, and the machine housing 20. The machine frame 19, and in a further embodiment the entire machine superstructure 22, is / are supported or erected on the decoupling device 21 at a distance from the stationary floor 3.The decoupling device 21 can, for example, be designed as a self-contained intermediate frame 23, which, by way of example, has four support points 24 for placement on the stationary floor 3. It is understood that for a larger or heavier spinning preparation machine, additional support points 24 may be added, or that for a smaller spinning preparation machine, three support points 24 can generally ensure secure support. Each of the support points 24 is provided with a support foot 25, which is particularly height-adjustable, to align the decoupling device 21 with the floor 3.

[0068] The weighing device 26 for gravimetric level measurement of the flake storage 4 is arranged between the intermediate frame 23 and the machine frame 19. It is positioned in the force flow between the filling chutes 5 and the stationary base 3. Specifically, as shown here, the weighing device 26 can have several load cells 27 on which the weight of the machine superstructure 22 rests. Damping elements 28 can be arranged between the load cells 27 and the decoupling device 21, exemplified here by the intermediate frame 23. To prevent vibrations of the fan 10 from distorting the measurement results obtained with the weighing device 26, the platform 30 for the fan 10 can be supported on the decoupling device 21. The pipe support 32 for the fiber flake discharge 18 can be supported on the intermediate frame 23. Reference sign 1 Spinning preparation machine 70 Empty operation 2 fiber flakes 71 Step 3 Floor 72 Step 4 Flake storage 80 Automatic operation 5 Filling shaft 90 output 6 Feed channel 7 floor opening 8 inlet 9 Fiber flake inlet A Feeding or transport direction 10 fan L Fresh air supply 11 Closure device X Longitudinal direction 12 Dosing device Y transverse direction 13 feed roller Z Upward direction 14 feed roller 15 Opening roller 16 Mixing channel 17 Outlet 18 Flake discharge 19 machine frame 20 Machine housing 21 decoupling device 22 Machine construction 23 Intermediate frame 24 Support point 25 support leg 26 Weighing device 27 Load cells 28 Damping element 29 Hose element 30 platform 31 Hose element 32 Pipe bracket 33 partition 34 Extraction device 35 Infeed roller pair 36 actuator 37 Control unit 38 Main axis 39 connecting line 50 start 51 Step 60 Filling operation 61 Step 62 Step

Claims

1. Spinning preparation machine (1) for processing fiber flakes (2), wherein the spinning preparation machine (1) can be supported on a stationary floor (3) via several support points (24), comprising: several adjacent filling chutes (5), a feed channel (6) arranged above the filling chutes (5), which is connected on the inlet side to a central fiber flake inlet (9) and has a bottom opening (7) on the outlet side for each filling chute (5), a control unit (37), a weighing device (26) connected to a control unit by signal, which is arranged in the force flow between the filling chutes (5) and the stationary floor (3) and has several load cells (27) which are arranged at a subset of the support points (24), characterized by thatthe support points (24) equipped with the load cells (27) lie on an imaginary connecting line (39) which is aligned parallel to a main axis (38) of the spinning preparation machine (1).

2. Spinning preparation machine (1) according to claim 1, characterized by that several closure elements (11), which are adjustable by means of actuators (36), are arranged in the feed channel (6) and that the control unit (37) is configured to control the actuators (36) for filling the filling chutes (5) with the fiber flakes (2) in such a way that, due to the positioning positions of the closing elements (11), only one of the bottom openings (7) is connected to the central fiber flake inlet (9) at any given time, and that a discharge device (34) which is connected on the inlet side to the filling chutes (5) and on the outlet side to a central fiber flake discharge (18) is arranged below the filling chutes (5).

3. Spinning preparation machine (1) according to one of claims 1 or 2, characterized by that the spinning preparation machine (1) has a machine frame (19) to which the filling chutes (5) are attached.

4. Spinning preparation machine (1) according to claim 3, characterized by that the load cells (27) are arranged between the machine frame (19) and the stationary floor (3).

5. Spinning preparation machine (1) according to claim 3, characterized by that The spinning preparation machine (1) has a decoupling device (21) with at least four support points (24) for setting up on the stationary floor (3), wherein the machine frame (19) and the decoupling device (21) are structurally separated from each other, and the load cells (27) are arranged between the decoupling device (21) and the machine frame (19).

6. Spinning preparation machine according to one of claims 2 to 5, characterized by that The spinning preparation machine (1) is configured to perform the following gravimetric level measurement procedure: 4) measuring a change in weight force using the weighing device (26) in a defined time interval during a filling and / or emptying process; 5) calculating a change in the filling weight of the filling chutes (5) by the control unit (37) from the change in weight force in the defined time interval; 6) calculating the filling levels of the filling chutes (5) by the control unit (37), whereby the change in filling weight is distributed to the at least one filling chute (5) that was connected to the fiber flock inlet (9) in the defined time interval due to the positions of the closing devices (11).

7. Spinning preparation machine according to claim 6, characterized by that In this process, process steps 1) - 3) are repeated during the filling and / or emptying process.

8. Spinning preparation machine according to claim 6 or 7, characterized by that The discharge device (34) has a feed roller pair (35) for each filling chute (5), wherein the control unit (37) takes into account a feed roller rotation speed of the feed roller pairs (35) for calculating the fill levels.

9. Spinning preparation machine according to claim 8, characterized by that The control unit (37) calculates the production of the spinning preparation machine (1) as a function of the feed roller speed from the change in the weight force, which is measured by means of the weighing device (26) in a time window in which no feeding of the filling chutes (5) takes place.

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