Method and device for monitoring a wear structure, in particular a sealing structure

Abstract

A method for monitoring a wear structure including at least one wear element in a machine for generating or processing a fibrous material web, includes providing a time at which the wear element became operational, providing a time at which a defined first wear level of the wear element was reached, providing at least one further characteristic variable, and predicting a remaining operating time of the wear element from the knowledge of the times, in particular from a time difference between the times, as well as from the at least one further characteristic variable, by using a computer system. A device for carrying out the method is also provided.

Claims

1. A sealing assembly, comprising: a device for monitoring a sealing structure including at least one sealing element for sealing at least one negative or positive pressure zone adjoining a surface moving in a direction of movement in a machine for producing or processing a fibrous web; at least one wear sensor associated with said at least one sealing element; a signal transmission device for transmitting a signal from said at least one wear sensor; and a computer system receiving the signal from said signal transmission device, said computer system being configured to carry out the following steps: providing a time z0 at which the sealing element became operational; providing a time z1 at which a defined first level of wear of the sealing element was reached; providing at least one further characteristic variable describing a machine speed, operating times of the machine, stoppage times of the machine, at least one of type or quantity of products being produced, or a contact pressure of the sealing element onto the moving surface; and predicting a remaining operating time of the sealing element from the times z0 and z1 and the at least one further characteristic variable.

2. The sealing assembly according to claim 1, wherein the computer system predicts the remaining operating time of the sealing element from a time difference between z0 and z1 and the at least one further characteristic variable.

3. The sealing assembly according to claim 1, wherein said at least one wear sensor includes a plurality of wear sensors.

4. The sealing assembly according to claim 1, wherein said at least one wear sensor includes at least one of a wear sensor indicating a level of wear of between 80% and 50% of a remaining wear or a wear sensor indicating a level of wear of between 20% and 10% of the remaining wear.

5. The sealing assembly according to claim 1, wherein said at least one wear sensor includes at least one optical fiber, an electrical conductor, a temperature sensor or a hose being filled with a medium, and said optical fiber, electrical conductor, temperature sensor or hose is destroyed with progressive wear of said sealing element.

6. The sealing assembly according to claim 1, wherein said computer system is configured to carry out the following steps: providing additional further characteristic variables in addition to the characteristic variable; and incorporating the further characteristic variables into the step of predicting the remaining operating time.

7. The sealing assembly according to claim 6, wherein said computer system is configured to carry out the following step: using at least one of the further characteristic variable K1 or one or more of the additional further characteristic variables to describe one or more aspects of an operating mode of the machine.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 shows, schematically, the essential components of the method according to the invention.

(2) FIG. 2 shows, schematically, a detail from a sealing strip in a device according to the invention.

(3) FIGS. 3 and 4 show, in a purely schematic illustration, an exemplary embodiment of a system for monitoring the state of a screen basket according to the further inventive idea.

DESCRIPTION OF THE INVENTION

(4) FIG. 1 shows, schematically, a sealing strip 1 which is in frictional contact with a moving surface 200. This sealing strip 1 can be used in a suction roll to seal off a suction or blowing zone with respect to the surroundings. However, it can also be in contact with a fabric, in particular a wire or a press felt, in order for example to seal off a suction box. The sealing strip 1 in FIG. 1 comprises a wear sensor 2. This sensor 2 generates a signal as soon as a defined level of wear of the sealing strip 1 is reached. FIG. 1 shows a sealing strip 1 comprising a sensor 2, but sealing strips 1 frequently comprise multiple wear sensors, preferably two or three. As a result, it is possible to define multiple levels of wear at which, when they are reached, the sealing strip 1 transmits a signal. Advantageously, one of the levels of wear can be defined between 80% and 50% remaining wear. The exact knowledge of reaching a comparatively early level of wear makes it possible to determine a first prediction of the remaining operating time of the sealing element 1 very early.

(5) Likewise, it may be advantageous if one of the levels of wear is defined between 20% and 10% remaining wear, preferably between 20% and 15% remaining wear. The exact knowledge of reaching a comparatively late level of wear permits a more accurate prediction of the remaining operating time of the sealing element 1. However, the sensors 2 can also be positioned such that they provide a signal at levels of wear other than those specified above, in particular also between 50% and 20% remaining wear. However, it is important for the method to know at what level of wear the respective sensor 2 transmits a signal. This is defined before the installation and the sensors are positioned appropriately.

(6) The sensor signal is transmitted to a computer system via a signal line 5. The transmission can be carried out in a cable-bound or cable-free manner, for example via WLAN, Bluetooth or similar suitable signal lines 5. In the example shown in FIG. 1, one or more further characteristic variables are additionally transferred to the computer system 3. These characteristic variables are transmitted here by the control system 6 of the machine and can describe operating states of the machine, such as, for example, machine speeds, operating times of the machine, the stoppage times of the machine, the type and/or quantity of the products produced, or the contact pressure of the sealing element onto the moving surface. These characteristic variables can be transmitted to the computer system 3 continuously or at specific discrete times.

(7) On the basis of the time z0 at which the sealing strip 1 was installed and the time z1 at which a specific level of wear was reached, together with the further characteristic variables from the control system 6, the computer system 3 calculates a prediction for the remaining operating time of the sealing strip 1. The time z1 is transmitted here by means of a signal from the sensor 2 in the sealing strip 1. If more than one sensor 2 is installed, if appropriate signals are transmitted to the computer system 3 at further times z2, z3, z4 . . . , by which means the prediction can be improved by renewed calculation.

(8) The sensors usually supply a signal to the computer system 3 only at the discrete times z1, z2, z3, z4 . . . . At the times in between, the computer system updates the remaining running time continuously by using the characteristic variables from the control system and the current time.

(9) The computer system 3 usually has a display device 4, on which the remaining operating time can be displayed.

(10) FIG. 1 shows the computer system 3 and the control system 6 as physically separated objects which are connected to each other by means of a cable-bound or cable-less signal line 5a. However, it is also possible for the two computer systems to be implemented in one unit. In this case, the calculation of the prediction of the remaining operating time can be carried out on a computing unit of the control system 6. The remaining operating time can then be displayed, for example, on one or more monitors in a control room of the machine.

(11) In the system shown in FIG. 1, the computer system 3 is additionally connected to a further computer system 7 via a signal line 5b. This can be an electronic procurement system 7. Once the remaining operating time of the sealing strip 1 reaches a previously defined threshold value, a signal can then be transmitted to the procurement system 7 in order to trigger a timely purchase of a new sealing strip 1 or the like. Alternatively or additionally, when another or the same threshold value is reached, a signal can also be transmitted to a further computer system 7 which plans or administers the planning of maintenance work on the machine.

(12) FIG. 2 shows a detail of a sealing strip 1 for a device according to the invention. The sealing strip 1 has a certain maximum wear volume 30 in the direction of wear V. Once this volume 30 has been removed by the frictional contact of the sealing strip 1 with the moving surface 200 or by other effects, the sealing strip 1 can no longer fulfill its function and it is even possible for damage to occur to the moving surface 200, for example the suction roll shell or the fabric. The remaining operating time of the sealing strip 1 is therefore the time interval until the maximum wear volume has been removed completely over the length L of the sealing strip 1, at least at one location. In the sealing strip shown in FIG. 2, three wear sensors 2a, 2b, 2c are provided. They can each be implemented as a hose which is filled with a medium, for example air or water. However, other types of wear sensors 2a, 2b, 2c are also imaginable, such as, for example, optical sensors (optical fibers) or electrical conductors. The first sensor 2a can be positioned, for example, such that it outputs a signal as soon as only a level of wear between 80% and 50% of the maximum wear volume 30 is still available. The third sensor 2c can be positioned, for example, such that it outputs a signal as soon as only a level of wear between 20% and 10% of the maximum wear volume 30 is still available. The second sensor 2b can be positioned between the two others and, for example, output a signal as soon as only a level of wear between 40% and 30% of the maximum wear volume 30 is still available. These values are to be understood as exemplary and can also be considerably different, depending on situation and installation position.

(13) It is advantageous that the last sensor 2c is positioned such that, at the time of the sensor signal or reaching the appropriate level of wear, sufficient operating time of the sealing element 1 still remains that sufficient time is left for planned and controlled maintenance or replacement of the sealing elementpreferably within the context of a routine stoppage of the machine.

(14) In the drawing, FIG. 3 shows, in a purely schematic illustration, an exemplary embodiment of a system 10 for monitoring the state of a screen basket 12 of a screen for treating a fibrous suspension according to the further inventive idea.

(15) According to FIG. 4, the system 10 comprises a cable-free identification unit 14 assigned to the screen basket 12 arranged in a housing 24 of the screen, and an external, in particular mobile, reading unit 16 for the non-contact reading of technical data 18 relating to the screen basket 12 from the identification unit 14 and for producing a connection to an external database 20 containing further data relating to the screen.

(16) The reading unit 16 can comprise a display for reproducing further data relating to the screen and retrieved from the external database.

(17) The identification unit 14 can comprise at least one RFID chip. In this case, it comprises at least one RFID chip assigned to the screen basket 12 of the screen.

(18) According to an exemplary embodiment of the system according to the further inventive idea, the identification unit 14 can comprise both an RFID chip assigned to the screen basket 12 of the screen and an RFID chip assigned to the housing 24 of the screen, wherein the RFID chip assigned to the screen basket 12 can be coupled via software coupling to the RFID chip assigned to the housing 24, and the RFID chip assigned to the housing 24 can be read via the reading unit 16.

(19) According to an alternative exemplary embodiment of the system 10, the RFID chip assigned to the screen basket 12 of the screen can also be readable directly via the reading unit 16.

(20) In particular in the case in which the RFID chip assigned to the screen basket 12 of the screen is readable directly via the reading unit 16, the RFID chip assigned to the screen basket 12 of the screen is expediently arranged in the region of the opening of the screen that can be closed via a cover.

(21) The RFID chip assigned to the screen basket 12 of the screen can in particular be arranged on or in an end ring 22 of the screen basket 12 that is adjacent to the opening of the screen that can be closed by a cover. In the present case, the RFID chip assigned to the screen basket 12 of the screen is accordingly arranged on or in the upper end ring 22 of the screen basket 12.

(22) The RFID chip assigned to the screen basket 12 of the screen can be arranged, for example, on the upper side of the end ring 22, facing the opening of the screen, or else on the radial inner side of the end ring 22.

(23) However, also conceivable, for example, is an embodiment in which the RFID chip assigned to the screen basket 12 of the screen is accommodated so as to be countersunk in the end ring 22. The RFID chip accommodated so as to be countersunk in the end ring 22 of the screen basket 12 can be provided with a covering consisting in particular of plastic and preferably of Teflon. By using such a covering, account is taken of the fact that the screen basket 12 is generally reconditioned, i.e. chromium-plated and electro-polished.

(24) The further data relating to the screen can be stored together with the technical data relating to the screen basket 12 in the external database 20. Via the technical data 18 read from the identification unit 14 of a respective screen basket 12, the relevant further data contained in the external database 20 can thus be assigned to the screen basket 12.

(25) The further data relating to the screen that can be retrieved from the external database 20 via the reading unit 16 can in particular comprise production data of the screen basket 12, service life data of the screen basket 12, operating data of the screen and/or the like. The production data of the screen basket 12 comprises, for example, data relating to the design, the material, the size or the like of the screen basket 12. The service life data of the screen basket 12 can comprise, for example, data relating to the reconditioning of the screen basket 12, storage times and so on. The operating data of the screen comprises, for example, data relating to the running time, the flow/pressure at the end ring/outlet of the screen, data relating to the rotational speed of the screen basket 12 and/or the like. The relevant information can in particular be supplied by the machine control system of the screen.

(26) Such a system can also be monitored by means of the method according to the invention. As a result, a prediction of the remaining operating time of the wear element 12, that is to say of the screen basket 12, is supplied. This information can be used, for example, for optimizing the stoppage planning.

(27) In addition, the system 10 according to the further inventive idea, for example, can comprise data-processing means integrated in the reading device 16 and/or in the external database 20, in order, on the basis of the service life of previous screen baskets, the entire throughput previously treated by the screen basket 12, the rotational speed of the screen basket 12, the energy balance between the end ring and the outlets of the screen and/or the like, to determine the level of wear of the screen basket 12 and therefore the next change date for the screen basket 12.