EP3230501A1 - Method and device for loading an installation with fibres - Google Patents

Abstract

The invention relates to a method and a device for loading an installation with fibres, said installation being fed with fibre tufts, the latter being at least partially opened and fed to a pneumatic loading installation by means of a feeding device, said pneumatic loading installation guiding the fibres into the store of at least one fibre-processing machine, in particular a carding machine, separator or cleaner. The invention is characterized in that, by means of a control loop, into which the current pressure values, which are measured in the pneumatic loading installation, enter in a further-processed manner, and into which the mass flow of the further-processed fibres, which is measured at at least one fibre-processing machine, enters in a further-processed manner, the optimum operating point of the installation is determined by means of a control algorithm and a signal is sent to an actuator of the feeding device in order to control the quantity of fibre tufts.

Description

 Title: Method and device for feeding a plant with fibers

 description

The invention relates to a method and a device for feeding a system with fibers supplied to the fiber flakes, these at least partially dissolved and fed by means of a feeder to a pneumatic charging system, the fibers in the memory of at least one fiber-processing machine, in particular a card, carding, Opener or cleaner, conducts.

The flow of material within cleaning plants or spinning preparation plants is ensured by mechanical, electrical and pneumatic means. In the case of a pneumatic filling of a machine, the density and height of the filling can be determined via a selected target pressure. The uniformity of filling, i. adherence to the target pressure determines the uniformity of the material template. As a result, compliance with the production and quality of the product is affected.

The classic solution is based on a manual device of a controller or a regulator of the material-conveying machine to achieve a sufficient and constant filling of the following machine. Knowledge of the desired production, the basic material properties and the expected drive values are prerequisites for set-up operation. These steps and knowledge are necessary every time you change the production or the source material. In addition, due to variations in material properties, it may be necessary to make continual corrections to the Production time. The uniformity of the filling is essentially determined by the appropriate, manual choice of the operating point, ie the control parameters.

Variations of the material and / or the material properties (resolution, density, humidity, temperature), non-deterministic fluctuations in the discharge of cleaning machines, as well as changes in the production itself lead to fluctuations in the operating point of the material-conveying machine and thus to fluctuations in the filling the following machine. Fluctuations in the filling can lead to quality fluctuations of the product or production failures. Based on existing solutions, these fluctuations in the operating point of a machine or machine sequence can only be corrected by continuous manual intervention in the setting values.

In DE 10064655 B4, a pressure measuring device is installed in a pneumatic supply and distribution line upstream of the card, which conducts the differential pressure as an electrical signal to a controller. Via a control device, the differential pressure over time is used to generate a corrected pressure actual value, with which a drive of a flake conveyor is regulated. As a result of the slope of the curve of the pressure with respect to time, temporally increasing, constant or decreasing pressure values can be anticipated and thus the feed of the flakes can be adjusted accordingly.

A disadvantage of this method is that the adjustment of the control or regulation of the material-conveying machine to achieve a sufficient and constant filling of the following machine, such as a card, must be done manually.

It is the object of the invention to remedy the aforementioned disadvantages and to regulate the material flow in an automated and precise manner. The invention solves the problem by the teaching of claim 1 and 10; Further advantageous features of the invention are characterized by the subclaims.

According to the technical teaching of claim 1, the method for feeding a system with fibers, the fiber flakes supplied, these at least partially dissolved and fed by means of a feeder to a pneumatic charging system, the fibers in the memory of at least one fiber-processing machine, in particular a card, Carding, Öffner or cleaner, conducts, a control loop, in which the pressure-actual values, which are measured in the pneumatic charging system and further processed, and in the mass flow of the further processed fibers, which is measured on at least one fiber-processing machine and further processed, the Control loop determines the optimal operating point of the spinning preparation plant by means of a control algorithm and a signal is passed to an actuator of the feeder to control the amount of fiber flakes.

With these values or associated signals, the control circuit continuously determines the discharge quantity of the flake-feeding machine as a function of the setpoint and actual production of the fiber-processing machine. Variations of the material or material properties, production fluctuations and other disturbing factors (such as shutdowns of individual machines) are automatically compensated by the control loop.

In an advantageous embodiment, it is provided that the signal for regulating the supply device is fed back into the control loop and there again passes through the control algorithm. The control loop adapts continuously due to the return of at least one signal for a manipulated variable to the optimum operating point and "learns" the production and the effects of the changes due to variations in material properties. In addition, the non-deterministic linearity deviations of the material-conveying machine are processed and compensated in the control loop. This always takes place without manual intervention and automatically leads to compliance with the targets and a constant filling of the following machine.

In a preferred embodiment, the stored control algorithm for starting up the spinning preparation plant starts from a constant mass flow of supplied fiber flakes. This results in a suitable, automated starting value estimation, which additionally reduces the initial learning phase to a minimum.

The operating point of a machine or plant for fiber processing is continuously and automatically determined by the control algorithm which adapts to the working conditions. The device according to the invention for feeding a system with fibers according to claim 10, the fiber flakes at least partially dissolved and fed by means of a feeder to a pneumatic charging system, the fibers in the memory of at least one fiber-processing machine, in particular a card, carding, NC or Cleaner, directs. The invention is characterized in that by means of at least one controller, which is part of a control loop, in which the actual pressure values, which are measured in the pneumatic charging system and further processed, and in the mass flow of the further processed fibers, the at least one fiber-processing machine measured and further processed, the optimum operating point of the system determined by means of a control algorithm and a signal is passed to an actuator of the feeder for controlling the amount of fiber flakes. According to the device of the invention, the control loop is formed by a total of three controllers X1, X2 and X3, which have different functions. The controllers X1 and X3 are functionally disconnected from the controller X2, as there is no feedback from the controller X2 to the controllers X1 and X3. From the signals to the mass flow of the processed fibers and from the processed pressure signal from the pneumatic charging system, the controller X2 continuously determines the discharge quantity of the flake-feeding machine and regulates the associated actuator via the signal z, with which the drive for the fiber feed and thus for the supplied mass flow is regulated. The fact that the signal z is returned to the controller X2 back and there runs through the control algorithm again, the control loop is optimized even without manual intervention.

The assumption of small fluctuations with a known and constant mass flow of supplied fibers allows a fast start-up of the plant to the optimum operating point of the fiber-processing machines.

The invention will be described by way of example with reference to the accompanying drawings; in these shows

1 shows a schematic view of a spinning preparation plant with a block diagram of the device according to the invention;

FIG. 2 is a functional diagram of a prior art spinning preparation apparatus; FIG.

3 shows a functional diagram of a system according to the invention when the system is started up;

Fig. 4 is a functional diagram of the system according to the invention in operation.

In the spinning preparation plant according to FIG. 1, the fiber material F is fed to a cleaner 1 by a bale opener, not shown, via a mixer (not shown). From the last roll of the cleaner 1, the opened and cleaned fibers or fiber flakes are conveyed pneumatically via a pipe 2, a dedusting machine 3, a fan 4 into a pneumatic supply and distribution line 5, to which a flock feeder 6 with at least one card 7 is connected are.

The flock feeder 6 has an upper reserve shaft 6a and a lower feeder shaft 6b, between which a flake conveyor may be arranged in the form of a slow-speed pick roller 6c and a high-speed opening roller 6d. The feed roller 6c can cooperate, for example, with a collecting trough, not shown over the width of the flock feeder 6. The indentation tray may be associated with an inductive position transducer, which are connected via a computer to a controller. As a result, changes in the mass of the conveyed fiber material are detected and converted into electrical signals.

In order to determine the amount of fiber produced, at the output of each card 7, an unillustrated sliver funnel or an alternative device can be arranged, which are arranged downstream, for example, two take-off rolls. The sliver funnel or the alternative device have a sensor 14, with which the amount of fiber produced can be determined and forwards the corresponding signals for the mass flow rh1 to the controllers X1 and X2.

This can be done, for example, by a spring loaded tongue, which is rotatable about a hinge. The tongue works together with an inductive position transducer, which is connected to a controller X1 and X2. In this way, the amount of fiber produced, that is the mass flow rh1, can be determined via the strip thickness as a function of the strip speed.

In practical implementation, the signal for the mass flow rh1 enters the card control, which forwards this value or an associated signal to the controllers X1 and X2.

In a wall of the supply and distribution line 5, a pressure sensor 8 is mounted, which is in communication with a transducer 9. In this case, the measured actual pressure values p1 are converted into electrical signals x and entered into a controller 10, for example a computer. In the controller 10, an electrical signal y for a corrected pressure actual value is generated by differentiating the differential pressure over time. This signal y with the corrected pressure actual value is fed back to an electronic controller X3. Via an input device 12, a pressure setpoint can be entered as a reference variable in the controller 10 and in the controller X3. The difference between reference variable and controlled variable is given as signal v in the controller X2.

By measuring the actual pressure values p1 in the supply and distribution line 5 and the mass flow rh1 of the discharged sliver on the carding machine 7 and the comparison with the reference variables, the control circuit determines the feed rate and thus the mass flow rh2 supplied to fibers in the cleaner.

So that the control loop always finds the optimum operating point for the spinning preparation plant without manual readjustment of fiber qualities or material fluctuations during removal of the fiber bales, the invention provides at least two controllers X1 and X2, wherein the controller X1 is functionally separated from controller X2, since no feedback from controller X2 takes place at X1. Regulator X1 uses the card control to request the desired target production and compare it with the current actual production. The control deviation between the target production and the actual production enters the controller X2 as signal u.

The controller X2 can be designed as a PI controller, assuming low fluctuations from a known mass flow rh2 to fibers F, and determines the optimum value for the card production via a computer on the basis of the current card production rh1. The controller X2 thus starts from a constant fiber feed rh2 (start value estimation), which may in fact be subject to wide fluctuations in order to determine the optimum operating point for the current card production with a mass flow rh1. With this start value estimation by the controller X2, the startup of the system can be accelerated to the actual optimum operating point. The output value for the constant fiber feed is the optimal (stored) operating point from the last operation of the system. By assuming a constant fiber feed rh2 of the controller X2, reaches the control loop in a very short time, an approximation to the optimum operating point of the card 7

In addition to the value from the signal u, the controller X2 continues to process the signal v for the difference between the reference variable and the controlled variable from the controller X3. As an additional value, the current card production rh1 minus the disturbance variable S1 for the variable degree of purification in the controller X2 is processed.

From these three signals u, v and rh1, the controller X2 continuously determines the discharge quantity of the flake-feeding machine with the mass flow rh2. The associated signal z controls the actuator drive 20 for the conveyor belt and the feed rollers a, 1b, whereby the amount of fibers F can increase or decrease. Via the input device 13, the speed for the actuator drive 20 can be limited to limit the maximum impact production for technological reasons. At the same time, the signal z for controlling the actuator drive 20 is fed back into the controller X2 and there indirectly compared with the signal u and optimized taking into account the further signals v and rh1. Within the controller X2, the signal z is processed together with the signal from the current fiber or mass flow rh1 and the resulting result is processed with the result from the signals rh1, u and v processed together to form a new value or signal z. The order of the signals processed in the controller X2 is an essential basis for the control algorithm. The feedback of the already evaluated signal z ensures a new pass through the control algorithm with a new value for the signal z, whereby a differentiating behavior arises.

By returning the signal z and the indirect comparison with the signal u, the spinning preparation plant can work very continuously without fluctuations. The feedback of the signal z ensures a fast match to the current optimal operating point, which allows the loop to self-optimize and therefore be referred to as "self-learning".

A further improvement can be achieved by an upcoming can change or a card stop or a restart of the card as a signal w in the controller X2 is fed from the controls or the cards to take into account an upcoming production fluctuation, which is characterized by more or less fibers with possibly a pressure change in the supply and distribution line 5 makes noticeable.

With the number of cards 7, the supply and distribution line 5 is longer, whereby the material running times increase, and thus the pressure in the supply and distribution line 5 is subject to greater fluctuations. To take this into account, the material delay can be determined in the controller 10 as the signal t and entered into the controller X2. This makes it possible to watch pressure fluctuations due to the slope of the pressure curve over the material life before, and to compensate for the or the fans 4 and / or the actuator drive 20.

For reasons of clarity, only one card 7 has been shown in FIG. Usually, several cards are connected to the distribution line 5, all of which are fed by the fiber processing plant (mixer, cleaner 1, dedusting machine 3), each carding machine 7 having its own flock feeder 6. Instead of cards, the control loop can also be used for any other fiber-processing machine or installation, such as web-forming machines or for spinning preparation systems for filling fiber memories.

The algorithm for the control loop is such that variations of the material or the material properties, as well as production fluctuations and the other disturbing factors such as Example, the shutdown of individual machines by a feedback of at least one signal (controller X2) are automatically compensated by the control loop. The control loop adapts continuously to the optimum operating point and "learns" the production and the effects of the changes due to variations in the material properties, and the non-deterministic linearity deviations of the material-conveying machine are learned and compensated this always without manual intervention and leads automatically to a compliance with the optimum operating point for the cards and a constant filling of the feed shafts. A suitable, automated start value estimation (controller X2) reduces the startup phase to a minimum. It is no longer necessary to program the loop with fiber data. Only the damping of the control loop due to the dead time with a larger pipe length, for example, when enlarging the supply and distribution line 5 due to other cards, must be set. As input values, only the pressure setpoint in the input device 12 and the maximum speed in the input device 13 are required. Material-specific data is no longer needed because the control loop automatically searches for and adapts to the optimum operating point.

Although this is not explicitly disclosed in the exemplary embodiment, the control loop can also process further disturbance variables such as, for example, the degree of soiling of the fiber flakes, strip breakage on the card or fluctuating moisture of the fiber flakes.

The regulators X1, X2 and X3 are preferably housed in a common assembly and need not be executed as separate components. The graphs in FIGS. 2 to 4 show the time in seconds on the abscissa. The left ordinate indicates the pressure in Pascal in the supply and distribution line 5, simultaneously the speed in% and the production in kg / h. The right ordinate displays an abstract dimensionless rule value.

Figure 2 shows a classic solution according to the prior art, in which a controller with manual operating point and fixed rule calculation is used. The target speed of the conveyor belt and the feed rollers 1a, 1b, the target production and the control value calculation are manually specified. Fluctuations in material properties with constant production can only be compensated by manual adjustment of the operating point.

Momentary fluctuations in current production (X-axis: 50-79 seconds and 90-115 seconds) can not be compensated for safely. This leads to significant fluctuations in the pressure curve (1100 Pa to 1450 Pa), which deviates greatly from the target pressure of 1250 Pa. This in turn leads to complete stops in the delivery (control value 0) of the feed machine (the drives for the feed belt and the feed rollers 1a, 1 b stand still) and thus to disturbances in the density of the filling of the following machines, such as the cards.

The first-time learning phase is shown in FIG. 3, in which the target production is automatically optimized and starts up in stages, since the cards are switched on one after the other. At the same time, the actual pressure in the supply and distribution line 5 drops and approaches the target pressure after about 220 seconds. The actual production is congruent with the target production after approx. 300 seconds. With the start-up or switching on the cards also gradually increases the actual speed of the drive for the conveyor belt or for the feed rollers 1a, 1b. A subsequent startup of the system is even shorter, because the last optimal Operating point is stored in the controller X2 and serves as a starting level for the start.

FIG. 4 shows the continuous adaptation of the optimum operating point. Fluctuations in material properties at constant production (see the left part of the diagram) are compensated by means of the "learning function" (feedback of at least one signal.) In the middle and in the right part of the diagram, production fluctuations are compensated in the same way. Due to the feedback of at least one signal into the control loop, all adjustments can be compensated automatically, without manual intervention and without fluctuations in the filling or production losses After a brief fluctuation, the actual pressure has approached the target pressure, and a stop in the supply of the feed machine and thus a considerable fluctuation in the filling of the following machine can be completely prevented and thus a uniform density and height in the filling, for example ka shafts are reached.

reference numeral

1 cleaner

 1a, 1 b feed rollers

2 pipe

 3 dedusting machine

4 fans

 5 supply and distribution line

6 flock feeders

6a reserve shaft

 6b feeder

 6c feed roller

 6d opening roller

 7 cards

8 pressure sensor

 9 transducers

 10 control

 12 input device

13 input device 14 sensor

 20 actuator drive

F fiber material

p1 pressure feedback

t signal

u signal

v signal

w signal

x signal

y signal z signal rh1 mass flow card rh2 mass flow fiber flakes

S1 disturbance

regulator

 regulator

 regulator

Claims

claims 1. A method for feeding a plant with fibers supplied to the fiber flakes, these at least partially dissolved and fed by means of a feeder to a pneumatic charging system, which directs the fibers into the memory of at least one fiber-processing machine, in particular a carding, carding, Öffner or cleaner , characterized in that by means of a control loop, in which the actual pressure values, which are measured in the pneumatic charging system and further processed, and in which the mass flow of the further processed fibers, which is measured at at least one fiber processing machine and further processed, the optimum operating point of Plant determined by a control algorithm and a signal is passed to an actuator of the feeder for controlling the amount of fiber flakes. 2. The method according to claim 1, characterized in that in the  Control loop, the mass flow of the processed fibers, the pressure difference between the control and controlled variable, and the control deviation between the target and actual production of the mass flow of the further processed fibers. 3. The method according to claim 1 or 2, characterized in that the signal for controlling the feeding device fed back into the control loop and there again passes through the control algorithm. 4. The method according to any one of the preceding claims, characterized in that the actual pressure values, which are measured in the pneumatic charging system, by a differentiation over time in a corrected pressure feedback value is converted and the resulting difference with a pressure setpoint in the control loop flows. Method according to one of the preceding claims, characterized in that the control algorithm for starting up the spinning preparation plant emanates from a constant mass flow of supplied fiber flakes. Method according to one of the preceding claims, characterized in that planned or unplanned fluctuating production quantities of at least one fiber-processing machine are processed in the control loop. Method according to one of the preceding claims, characterized in that fluctuations in the pneumatic charging system are incorporated by the determined fiber life in the control loop. Method according to one of the preceding claims, characterized in that the maximum amount of the fed fiber flakes is manually adjustable. Method according to one of the preceding claims, characterized in that the target pressure in the pneumatic charging system is manually adjustable. Device for feeding a system with fibers supplied to the fiber flakes, these at least partially dissolved and fed by means of a feeder to a pneumatic charging system, which directs the fibers into the memory of at least one fiber-processing machine, in particular a card, carding, opener or cleaner, characterized in that by means of a regulator (X2), which is part of a control loop, in which the actual pressure values (p1), which are measured in the pneumatic charging system and further processed, and in the mass flow (rh1) of the further processed fibers, the measured and processed on at least one fiber-processing machine, the optimum operating point of the system determined by means of a control algorithm and a signal (z) to an actuator of the feeder for controlling the amount of fiber flakes (rh2) is passed. 11. The device according to claim 10, characterized in that in the controller (X2) a signal to the mass flow (rh1) of the further processed fibers, a signal (v) to the pressure difference between the control and controlled variable, and a signal (u) to the deviation between Target and actual production of the Mass flow (rh1) of the further processed fibers. 12. The apparatus of claim 10 or 11, characterized in that the signal (z) for controlling the manipulated variable to the feeder in the controller (X2) returned and there again passes through the control algorithm. 13. Device according to one of the preceding claims 10 to 12, characterized in that the actual pressure values (p1), which are measured in the pneumatic charging system, converted by a differentiation over time into a corrected pressure actual value (y), in a controller (X3) with a Pressure setpoint compared and the resulting difference as a signal (v) flows into the control loop. 14. Device according to one of the preceding claims 10 to 13, characterized in that planned or unplanned fluctuating production quantities of at least one fiber-processing machine as signal (w) into the controller (X2). 15. Device according to one of the preceding claims 10 to 14, characterized in that the fiber life measured in the pneumatic charging system and as a signal (t) in the controller (X2) flows. 16. Device according to one of the preceding claims 10 to  15, characterized in that the supply device as a conveyor belt and / or feed roller (1 a, 1 b) is formed, which are driven by a variable drive, wherein the maximum speed of the drive (20) is manually adjustable. 17. Device according to one of the preceding claims 10 to 16, characterized in that the pneumatic charging system is designed at least as a supply and distribution line (5), the target pressure is manually adjustable.